External or Internal Disaster in Organization

Distinctive Business is influenced by interior and outer elements. These angles have huge impacts in transit business associations are working. One of these is the alleged debacles in an organization.Disasters might be considered as outer if the powers occurs from the outside condition of the association, similar to globalization, worldwide money related emergency, mechanical changes and others while web catastrophes are those that occurs inside the association like inability to offer quality assistance, powerlessness to showcase the items and administration well, failure to deal with dangers which influences the general execution of the organization.Primarily, the objective of this paper is to think about an interior fiasco from one of the most dubious associations in the market, I. . the instance of Enron. Interior Disaster Aforementioned, one of the most discussed issues and debacles in the business is the inspecting just as bookkeeping disappointment of Enron. It is considered as the biggest liquidation and stock breakdown (Fox 2003). Before the organization confronted this issue, Enron has been considered as a significant American vitality industry. The occasions or fiascos that came about to the liquidation and breakdown began well before anybody had presumed misrepresentation and inconsistencies at the industry.In this catastrophe, two names have been noted: Arthur Andersen and Enron. One of the calamities that tested the organization is the failure of the administration to envision the bad behaviors of Arthur Andersen. The fiascos are focused in examining perspectives not long before Enron sought financial protection. For instance in 1996, Andersen’s review report with respect to Waste Management funds were found to be insignificant and physically bogus that outcomes in swelling of Income of the organization by over $1 billion in the center time of the 1990s.On the other hand, in 1997, it has been discovered by the SEC that Sunbean has utilized b ookkeeping stunts to make bogus benefits and deals and Andersen’s job in this catastrophe is that he closed down these budgetary reports occasion after an industry accomplice hailed them. In this, the organization confronted serious calamity of joining forces or recruiting a reviewing and counseling enterprises which is doubtful and reckless. In spite of the fact that the organization has not known, Enron still has a few intends to forestall such issue.However, the activity of the organization with regards to their money related review has been feeble that it prompts their significant chapter 11. To have the option to tackle this sort of fiasco, Enron the executives has given calamity designs by recognizing the root f the issue. Subsequent to knowing the issue about Arthur Andersen, the administration promptly looks for outsider help to clear the issue by making Andersen pay for the outrages and oddities he has done.On one hand, another calamity looked by the organization is in accordance with the wasteful and key dynamic methodology and furthermore having uncertain and unclear firm financial and practice points. Despite the fact that Enron has some administration plan, the organization has not had the option to execute this arrangement well. For example, The CEO of Enron had different item designs which required major money related help; the association during that period was likewise experiencing serious debacles in their universal businesses.In expansion, it was not until Enron was monetarily flimsy did the organization begins to accomplish something. To determine this sort of debacle, the association actualized various methodologies. Nonetheless, the methodology of the organization just went from one significant calamity of misfortune to the next. In view of the disappointment of the administration of the association to have key dynamic, this lead to serious fiasco of speculations and organizations, the organization’s development eased back d own . Therefore a greater amount of its ineptitudes and disappointments had developed progressively evident (Zellner et al. 2001).Bankruptcy and different bodies of evidence against the organization had come about to their insolvency. What's more, different representatives of the association had lost their school reserves, life investment funds, and benefits alongside the breakdown of the organization. Thus, it tends to be said that the administration of Enron must have the option to have key dynamic for the future to constantly continue the quality of the organization. So as to tackle this fiasco, the association has had the option to start a legitimate and key dynamic of the company.Herein, the company’s choice ought to be made deliberately by distinguishing first the upsides and downsides of the choice that they made. The administration makes sure that everyone ought to consent to the choice so further clash or dangers inside the organization would not emerge. Great dynami c can be ascribed as one of the imperative factors that will assist the business with achieving its center crucial goal. This option is useful such that it can make the organization progressively serious and make due in the advertising condition. ConclusionThere are numerous exercises that can be gained from the instance of Enron and Arthur Andersen. It tends to be presumed that, in view of the instance of Enron, it is significant that each person in the business field should realize how to oversee or to deal with debacles, explicitly inside fiascos all together for the business to make progress and to have the option to oversaw it successfully. For our situation, it is significant that the exercises gained from Enron and Arthur Andersen outrage should fill in as illumination in making a productive hazard the board manual

Americas Violence Fixation Essay examples -- Media Violent Crime Essa

America's Violence Fixation Perhaps the most concerning issue today is brutality. It is going on all over the place, in the family units, out in the city, even in our schools. When we watch the news and see these demonstrations of savagery, we hear the fault be put to a certain something: amusement. Motion pictures and computer games are as far as anyone knows causing youthful individuals to carry on forcefully in the public eye, and possibly convincing them to slaughter. Some even accept that video rental stores ought to have approaches, such as continually requiring an ID, and that some TV projects, motion pictures, and games extol firearms and viciousness, just as the weapons themselves (center4policy.org). Valid, a few movies do depict murder and savagery as reasonable; movies, for example, Blade, in which the title character murdered vampires with an end goal to secure humankind, or The Matrix, where the primary characters utilized brutality to liberate humankind from a counterfeit knowledge. Computer games likewise have a lot of savagery in them too. The primary thought of Grand Theft Auto, one of the more mainstream video games, is to surpass a city, regardless of whether it implies utilizing viciousness. Players are permitted a different exhibit of weapons from play clubs to assault rifles to help them in missions. Appraisals are put on games, this specific one is appraised M for Develop. Retail locations are to check ID of clients all together for them to buy such games. Notwithstanding, that doesn't prevent kids from obtaining the games from others, or in any event, having clueless guardians purchasing them. The inquiry, be that as it may, is: Is amusement actually the reason for savagery? I have been influenced by and by the media's case that diversion causes savagery. One morning on the news program Good Morning... ...at certain individuals can't help contradicting a few structures and parts of amusement is splendidly fine; not every person will concur with some of it. Attempting to topple what the majority appreciate is a totally extraordinary issue. As a race, we overlook the right to speak freely of discourse; one voice consistently must be stronger than the other. By and by, as far as Terrific Theft Auto, Pokemon, and Harry Potter, individuals buy these on the grounds that they appreciate them, they are engaged by them, why not simply let them do their thing? I assume those who blame these live such perfect, healthy lives. The base line is: there are things that are well known, individuals will get them, be engaged, have, fun, and it will pass. Let them appreciate it. Sources http://www.pegmusic.com/savagery in-amer.html http://www.center4policy.org/violencec.html http://www.davekopel.com/Media/Irmassag.htm

Roller Coaster Phobia

Roller Coaster Phobia Phobias Types Print Why a Fear of Roller Coasters Is a Complicated Combination Phobia By Lisa Fritscher Lisa Fritscher is a freelance writer and editor with a deep interest in phobias and other mental health topics. Learn about our editorial policy Lisa Fritscher Medically reviewed by Medically reviewed by Daniel B. Block, MD on November 25, 2019 twitter linkedin Daniel B. Block, MD, is an award-winning, board-certified psychiatrist who operates a private practice in Pennsylvania. Learn about our Medical Review Board Daniel B. Block, MD Updated on January 24, 2020  Minoru Kuriyama / Getty Images More in Phobias Types Causes Symptoms and Diagnosis Treatment For many people, an essential part of any theme park vacation is the roller coasters; others suffer roller coaster phobia. If you suffer from roller coaster phobia, you may wonder how to get through your next theme park vacation. What Is Roller Coaster Phobia? To understand roller coaster phobia, it is necessary to first understand roller coasters. The original precursor to the roller coaster was the Russian Ice Slide, invented during the 17th century in Russia. Riders climbed a set of wooden stairs, slid down a 50-degree slope on a sheet of ice several inches thick, and then climbed up another set of stairs. The slides were so popular, it is rumored that Catherine the Great had a few installed on her property. It is uncertain who built the first wheeled roller coaster, although historians tend to lean toward the French. It is known that by 1817, two simple wooden coasters, with wheels that locked to the tracks, had been installed in French parks. Today, roller coasters may be created from either wood or steel. They use a combination of elements that may include chain lift hills, powered launches, steep inclines, and banked curves, as well as several types of loops including corkscrews, and even special effects, to invoke certain physical and emotional feelings. Roller coasters are intentionally designed to be scary, appealing to the same part of the brain that enjoys haunted houses and other Halloween events. We seem to be hardwired to enjoy activities that cause fear, provided that we know that we are actually safe. This phenomenon is demonstrated repeatedly in extreme sports, horror movies, and the multibillion-dollar Halloween industry. Understanding Phobias If our brains are hardwired to enjoy controlled fear, then why do so many people seem to suffer from roller coaster phobia? To answer that question, it is important to understand the basic psychology of fear as it relates to phobias. One aspect of anxiety disorders is the fear of fear. While most people are afraid only when confronted by a fear-inducing situation, those with anxiety disorders tend to worry that they will become afraid. They see fear as something negative, which must be avoided at all costs. A phobia occurs when the normal fear response becomes twisted. Objects or situations that are not inherently dangerous become the focus of fear. Although phobia sufferers know that their reactions are irrational, they are unable to control them. The Components of Roller Coaster Phobia Roller coaster phobia appears to actually be based on several other phobias, any of which can be enough to trigger a fear of coasters. Acrophobia: The fear of heights is a generalized phobia that may cover any experience of being up high. Severity varies dramatically between sufferers, ranging from fear only above a certain height to the inability to even climb a stepladder. Acrophobia is sometimes confused with vertigo, a medical condition that can cause dizziness or a spinning sensation (at any height). Roller coasters tend to be tall, with long drops, making them challenging for those with a fear of heights.Illygnophobia: The fear of vertigo may be related to the fear of heights. However, those with illygnophobia are not afraid to be up high. Instead, they are afraid that looking down might cause dizziness and vertigo. Although the difference is subtle, it is important. Those with illygnophobia may be afraid even on coasters that do not go very high, as they worry that the banked curves and other features may lead to dizziness.Claustrophobia: By design, roller coaster seats are small and tight, and the restraints fit extremely snugly. This is necessary for safety  but can trigger claustrophobia. Those who are uncomfortable with enclosed spaces often find that the worst part of a coaster is being locked down with no escape.Social phobia: Some people do not fear the roller coaster itself, but instead worry that they will have an embarrassing reaction to the coaster. Roller coaster trains tend to be long and hold a number of people. Those with social phobia may worry that they will be judged for screaming, cringing, or otherwise reacting to the coaster’s movements. Particularly in teenagers, this fear may be enhanced if the fearful person’s friends will also ride.Mysophobia: On a roller coaster, it is impossible to maintain much distance between yourself and those around you. Those with mysophobia, or fear of germs, may worry about coming into contact with strangers. In addition, there is always the possibility that someone on the coaster will vomit or urinate, possibly exposing the phobic person to those bodily fluids.Emetophobia: The fear of vomiting is surprisingly common. Those who suffer from this fear may go to great lengths to avoid situations that they feel could cause an upset stomach. As roller coasters are designed to be unsettling, the physical sensations could cause someone with emetophobia to skip the ride. A fear of roller coasters is not necessarily a phobia at all. Instead, it may be a very real concern based on the individual’s medical history. Virtually all roller coasters, even those designed for children, carry standard health restrictions. The exact restrictions depend on the coaster’s forces, but common considerations include (though are not limited to): heart conditions, back or neck disorders, motion sickness, high blood pressure, and perhaps recent surgery or casts. If you fall into any of the restricted categories, then it is best to err on the side of caution and skip the ride, at least until you have the opportunity to talk to your doctor about your safety and health. Conquering Roller Coaster Phobia If you have determined that your roller coaster phobia is not based on a legitimate medical concern, then you may be interested in taking steps to minimize or overcome your fear. Fortunately, there are measures you can take to conquer your phobia and even learn to love roller coasters. Take a Class Some theme parks sponsor Coasterphobia classes on an irregular schedule. Others are sponsored by local groups such as coaster enthusiast associations. These classes tend to follow the basic tenets of other  group seminars, and often build towards actually riding a specific roller coaster. Do your homework before paying for a class, though, to be sure that you are comfortable with the format, leadership, and expectations. Take Baby Steps Systematic desensitization  is an extremely popular therapeutic technique. If you feel comfortable on a smaller roller coaster, such as a kiddie coaster, you may be able to apply this technique yourself. Begin with a coaster that you are completely comfortable  with so that you will have success. Ride that one a few times before stepping up to a slightly scarier version. If your phobia is not severe, you may be able to slowly convince yourself to ride even the biggest and scariest coasters. Take your time and never force yourself to do anything. Bring a Friend A well-chosen  support person  can help you slowly work through your fears. He or she can preview each coaster before you ride, letting you know exactly what to expect. Your support person can also provide a hand to hold and a shoulder to lean on. However, it is important to choose your support person carefully. A support person should never try to force or guilt-trip you into  riding  or become upset by your decisions. At the same time, he or she should not be overprotective or try to talk you out of riding whatever you choose. Seek Professional Help If your  roller coaster phobia  is severe, it is always best to consult with a  mental health professional.  Therapeutic techniques, combined with  medications  if required, can help you tame your fears and learn to enjoy roller coasters. This is especially recommended if your roller coaster phobia is based on another fear, such as claustrophobia or fear of heights.

The History of Global Climate Change Essay - 1390 Words

Earth has experienced many episodes of dramatic climate changes with different periods in earth history. There have been periods during which the entire planet has been covered in ice and at another time it has been scorchingly hot and dry. In this regards, earth has experienced at least three major periods of long- term frigid climate and ice ages interspersed with periods of warm climate. The last glacial period which current glaciers are the result of it, occurring during the last years of Pleistocene, from approximately 110,000 to 10,000 years age (Clayton, 1997). Indeed, glaciers present sensitive indicators of climate change and global warming and by estimating and monitoring the dynamic evolution of these ice masses, several†¦show more content†¦Remote sensing has become a very valuable tool for documenting the response of glacier to changing climate (Bamber and Kwok, 2003; Kuhn, 2007; Pellikka, 2007; Solomon et al, 2007) because the rugged terrain, inaccessibility an d legendary poor weather of glacier areas has resulted in relatively few field- based studies. Indeed, in order to use glaciers and their changes as indicators of climate change, or as an early warning signal for sea level rise, remote sensing is the only tool to provide glacier change information from all the continents and from a large number of glaciers and ice sheets. On the other hands, because space borne and airborne remote sensing data provide superior cost- effective and area effective data and methods for monitoring the glaciers and their changes, part of this monitoring can be carried out by it. Glacier topography is one of the most important parameter to monitor as it is a key to glacier volume and glacier mass balance studies using the geodetic method. Topography of glacier can be mapped using various data types such as terrestrial photography, aerial photography, digital camera data, airborne radar data, satellite radar data (SAR), very high resolution satellite imager y and laser scanner data. By means of interferometric processing DEM could be retrieved by Synthetic aperture radar images withShow MoreRelatedClimate Change : A Changing For A Brighter Future1485 Words   |  6 PagesClimate Change: A Changing For A Brighter Future About 4.543 billion years ago, planet earth was created. As the years went on, the earth was starting to support life. Anything from bacterias, insects, animals and humans were starting to prosper and this was becoming a problem for the earth. As the earth was starting to support new forms of live, many of it resources were being used up and as a result, problems were arising. Problems such as is there enough water, food and resources were questionsRead MoreThe Climate Crisis And Its Effects On The Environment1428 Words   |  6 PagesThe climate crisis is a defining struggle of our age bringing political, economic, religious, and environmental tensions and conflicts to surface. At this moment in history a great transitional worldview needs to take place, but is depressingly out of reach, and humankind seems woefully unprepared/interested to confront monumental challenges and change. The climate change crisis directly affects planetary boundaries, ecological cycles, and limitati ons on a domestic and international level. It isRead MoreClimate Change : Global Warming875 Words   |  4 PagesThroughout the earth’s history, global climate patterns have fluctuated, with these climate patterns going through glacial retreat and advance (NASA 2014). Currently the earth is experiencing a retreat, this significant trend single handily points to human influence being the dominant cause of the observed temperature rise in global climate patterns since the mid-century (NASA 2014). The warming of global climate systems is undisputable supported by unprecedented observations, based upon direct measurementsRead MoreClimate Change And Global Warming1433 Words   |  6 Pagescentury. Little changes in the average temperature of the Earth can result into big and possibly to dangerous shifts in climate and weather. Rising temperatures around the world have been accompanied by differences in weather and climate. A lot of places have already seen changes in rainfall wh ich resulted in an increase in floods, droughts, or intense rain, as well as more continual and dangerous heat waves. The Earth’s oceans and glaciers have also experienced some great changes - oceans are warmingRead MoreGlobal Warming Is The Rise1536 Words   |  7 PagesGlobal warming is the rise in the earth’s average atmospheric temperature. When sunlight heats the ground surface, it releases most of the solar energy it has absorbed as infrared radiation. Then what is known as the â€Å"greenhouse effect† occurs, this is where the gases in the atmosphere absorb the re-radiated infrared radiation and the escape of these gases being released into space is prevented. As long as the composition of greenhouse gases in the atmosphere does not change, the heat in the atmosphereRead MoreThe Threat of Global Warming May Lead to Global Cooling Essay1631 Words   |  7 Pagesaccurate definition of global warming it can be roughly defined as a rise in average global te mperature according to Laurence Pringle’s book Global Warming Assessing the Greenhouse Threat (19). Global Warming Assessing the Greenhouse Threat also bring up that the average temperature data that scientist are using only goes back to 1860 giving scientists today only 150 years of temperature data. Also, with this current warming, even with humans contributing to the rising average global temperature, scientistRead MoreClimate Change is a Natural Phenomenon1556 Words   |  7 Pages Climate change has been an extremely controversial topic in recent history and continues to create much debate today. Many questions concerning climate change’s origins and its potential affect on the globe are not fully understood and remain unanswered. What is climate change? Is climate change happening? Is it a natural cycle of the world or are there other catalysts involved such as human activity? What proof is there? What data correlations show climate change is accelerated by humansRead More Political History of Global Warming Essay1101 Words   |  5 PagesPolitical History of Global Warming There is a lot of ambiguity surrounding the theory of global warming and the proper political response to it. At the very center of the scientific debate on the variability of global climate is to what extent human activities influence climate change. Another unforeseeable is whether the potential impacts of climate change will be harmful or beneficial for humans, managed agriculture, and natural ecosystems. Some question the authority with which currentRead MoreHuman And Natural Climate Change1485 Words   |  6 Pageswondered what could possibly be causing the change in our temperature? This essay delves into the meaning of climate change along with the human and natural processes that alter the globes atmospheric temperatures over a long period of time. It includes various mechanisms and feedbacks, the history of climatic change, human roles/impacts, as well as my own position on the subject. Natural Climate Change The focus of this section is to explore natural climate change- which occurs without any human influenceRead MoreThe Rationalization Of Global Warming1333 Words   |  6 PagesRationalization of Global Warming Global Warming is one of the most recent discussions within the scientific community and throughout its path towards acceptance scientist in agreeance with the model have to provide evidence of support for their claim. Kuhn’s process of discovery states that normal science is only thrown into a paradigm shift when a crisis emerges within the paradigm and the discoveries within the crisis lead to a revolution towards a new normal science. Within the scientific community

Differences Between Imperialism And Imperialism - 1618 Words

Sovereignty- The supreme authoritative rule over a country that is usually self-governing and reserves the right to be independent instead of interfering in other countries affairs. Contrariwise, no other power, individual, government, or entity may have the jurisdiction to supercede said sovereign power. Imperialism- A powerful nation or entity that transcends their authority upon other countries and states that are not as strong in an effort to take control. The idea of imperialism originates from the belief that if the stronger nations around the globe have the ability and the resources to counterbalance the issues of other countries then they should use those capabilities to take control and stablise them. The†¦show more content†¦In this particular cartoon, it depicts him with a giant bag of money labeled â€Å"Millions for a canal† while grabbing Columbia around the neck which appears to be indicative of a sense of greedy entitlement towards the panama canal and that he will take drastic measures to attain his personal goals of the betterment of the United States. Roosevelt also has the appearance as a very determined person and an intense credence of imperialism which is explained in writing in Roosevelt s Case for Supporting the Panamanian Revolution, 1903 and The Roosevelt Corollary, 1904 . In the documents mentioned above and the cartoon, he feels an acute need to intervene in the province of other nations not conducting themselves properly and, in the event that they do not, to act with imperialistic beliefs with aggressive reforms. Yes from my perspective it would be an accurate representation of the events that precipitated in Panama. For one, President Rooseve lt was very aggressive how he went about the action and how controversial the action was when he approached congress with it. He clearly intruded upon Colombia’s sovereignty. In fact, American Passages had this to say about it, â€Å"Roosevelt’s infringement on Colombian sovereignty produced hard feelings in Latin America..† (468). The Panama Canal movement caused bitter dissension in the government and he faced a lot of opposition. Many felt that he wasShow MoreRelatedDifference Between Formal And Informal Imperialism1721 Words   |  7 PagesDIFFERENCE BETWEEN FORMAL AND INFORMAL IMPERIALISM Name University Course Tutor Date Difference between formal and informal imperialism Throughout the history of the world, different kingdoms have been competing to expand their territories. In most cases, the expansion of theses territories has been at the expense of weaker territories that are incapable of fighting back effectively owing to different barriers . For example, the Mongols expanded their territory in less than a hundred yearsRead MoreDifferences Between Nationalism And Imperialism2099 Words   |  9 PagesKayla Melo J. Cormier CPW 4U1 Wednesday, October 29, 2014 Nationalism and Imperialism Whether it’s nationalism and/or imperialism we are affected by these angles all through out our lifetime, there are benefits to both nationalism and imperialism such that each can favorably support their nations respectively. These two features can be very powerful forces that can bring a nation together in its greatest time of need but may be able to subjugate another nation. By definition, nationalism is a patrioticRead MoreDifferences Between 16th and 19th Century Imperialism1896 Words   |  8 PagesThe Differences Between 16th and 19th Century Imperialism and their Effects on the World Today. Name: Mr. Big Student #: C10539956 Course: INS 201 Professor: Dr. Ventricle 1. What is ‘imperialism’? How did 19th-century colonialism, empire building, high imperialism differ from those of earlier times: in particular from the colonialism of early- modern mercantilism (16th to18th centuries)? ------------------------------------------------- ------------------------------------------------- -------------------------------------------------Read MoreImperialism and Colonialism Essay541 Words   |  3 PagesImperialism Imperialism is the policy or practice of a country extending its control over a foreign country’s land, economic life, or political system. The ruling country usually does this through conquest, and the native people of the nation being taken over are often suppressed. If a nation takes over the government of another territory militarily or through political means, then this is called direct imperialism. Indirect imperialism is when a region is self-governing but another country takesRead MoreA Passage to India: Imperialism1677 Words   |  7 PagesDiscuss Forster’s portrayal of Imperialism in the novel a passage to India A passage to India by E.M.Forster is a novel which deals largely with the political, economic and social takeover of India by the British Crown. The novel deals widely with colonialism and more specifically, imperialism. Forster presents the theme in question through the lives and minds of the characters from both the Indians and the English people. There is no subjective undertone to the novel and we see clearly how eachRead MoreCompare and Contrast the Influence and Consequence of European Imperialism on Africa and China During the 19th Century.748 Words   |  3 Pagesconsequence of European Imperialism on Africa and China during the 19th century. Imperialism is when one country dominates the cultural, economic, and political life of a nation weaker than itself. In the 19th century, Europe was the nation that was dominating both China and Africa. There were quite a few similarities in the way that European imperialism was changing these nations. One important similarity was that both the nations had resisted against British imperialism at one point. HoweverRead MoreImperialism In South Africa Essay1299 Words   |  6 PagesNasrallah, a political figure for Lebanon, â€Å"So long as there is imperialism in the world, a permanent peace is impossible†. Throughout history the countries that have experienced imperialism from other countries have seen how it brings only conflicts and not peace. Africa has been one of the largest places to experience imperialism. Imperialism has affected Africa in many ways for a long time. However, one specific example of how imperialism brought anguish to people is the country of South Afr ica. AnRead MoreThe Holocaust And Western Imperialism And The Holocaust1271 Words   |  6 Pagesatrocities. This has to be done since normal individuals cannot justify to themselves that they are immoral. Both western imperialism and the Holocaust had their atrocities justified by the illusion of progress. Even though numerous millions of people were slaughtered in these campaigns, many of the people doing the killing, believed that it was for the greater good. Western imperialism used the notion of bettering the native population and expansion in order to justify their mass killings. On the otherRead MoreEssay on Colonialism and Imperialism - The White Mans Burden1602 Words   |  7 PagesImperialism: The White Mans Burden      Ã‚  Ã‚  Ã‚   In one of his most famous poems, Rudyard Kipling said, Take up the white mans burden! (146). He was only one of many who believed in the virtues of imperialism in the late nineteenth and the early twentieth centuries. During that period, imperialism was on the rise, and Africa was being swallowed up by competing European nations. The imperialists had many arguments supporting imperialism. They said it was beneficial and, in some cases, essentialRead MoreGlobalization: Western Imperialism by Another Name Essay934 Words   |  4 Pages In our modern society the distance between individual nations is becoming smaller and gradually less important. As international trade and investment grow, the economies of these nations are becoming more integrated. This phenomenon has been labelled as globalisation. On the surface, globalisation seems like the most favourable path for the evolution of society, yet it can be argued that eventually the economy will be controlled by a few major organisations, remaining

Linguistic Relativity Hypothesis Free Essays

There are around 5000 languages in use today, and each is quite different from many of the others. Many thinkers have urged that large differences in language lead to large differences in experience and thought. They hold that each language embodies a worldview, which speakers of different languages think about the world in quite different ways. We will write a custom essay sample on Linguistic Relativity Hypothesis or any similar topic only for you Order Now At first I didn’t really understood what was being said, and I was really against it, but after asking myself, really? Knowing a different amount of words to describe things would allow us to better understand and communicate, interesting than as we started the color activity it became clear to me. Then immediately I started making connections to friends of mines form other foreign countries. Sometimes we have difficulties explain things to each other, things that are often the same, but because of where he’s from and the way their communication methods (Grammar, metaphors, Pragmatics, Semantics, Lexicon) are structured makes it difficult, to understand him being I’m form a different part of the world, meaning a different form of communication method, with a different set of rules. Form what I have read and understand the most important discussions of the linguistic relativity hypothesis have focused on grammar and lexicon which seem to be the most valid in my opinion. Why? I’m guessing it have something to do with the way we talk, and the influence it have on a lot of how much we understand, based on our vocabulary choices and makeup. For example a typical word order may vary in English; the common order is subject, verb, and object. In Japanese it is subject, object, and verb, and in Latin several different spin (word order). Languages can differ in whether they make a distinction between intransitive verbs and adjectives; there are many subtler sorts of grammatical difference as well. Grammar here does not mean the grammar we learned in grammar school, but the syntactic structure of a language; in the sense that grammar contains a set of rules that can generate all and only the sentences of a given language. How to cite Linguistic Relativity Hypothesis, Essay examples

Napoleon Bonaparte free essay sample

Napoleon Bonaparte was a military and political leader of France who made significant mistakes leading him to his downfall. Napoleon was a man obsessed with power and wealth. He was well known for his genius abilities of leading a full army, and winning impossible battles. Napoleon felt confident and believed he was more powerful than ever. But every single one of his accomplishments led him to wanting more, which is when everything began to go wrong. He made choices that were no good to France and it’s citizens. Napoleon’s three main errors will be explained in the following essay. Bonaparte’s first great mistake was indeed the Continental System. The continental system was a foreign policy. It was basically a strict restriction against British trade. Napoleon’s reason to such bizarreness was to attempt an invasion on the UK, and to defeat the Royal Navy at sea. He did not accomplish these attempts. We will write a custom essay sample on Napoleon Bonaparte or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page Napoleon then had the European nation under his full control, this only led to a very large debt. Eventually, Napoleon’s embargo failed miserably. The effect of this was very bad. Food imports in Britain dropped, and mainly the price of foods increased. This forced the Britain’s to begin smuggling with Continental Europe. But, even so, the continental system was not only affecting Europe and Britain, it was affecting many other nations, and France was on the list. Many industries that relied oversea markets began to decline, as well as buildings, and rope making. Profits were lost and no good was being done anywhere around. Napoleon caused much damaged to many, giving him the bad reputation that he began to gain, and mainly, his way on toward his downfall. Another well known mistake led to no good for the French as well. Napoleon did not learn from his first error, so he decided to take over and invade Russia. This was his most well known mistake. On 1812, the Russian defeated the French army that marked a hard hit to Napoleon’s ambition of invasion. The loss of the French was mainly because of an unintelligent move by Bonaparte. Bonaparte decided to move with his troops at a very wrong time, and the weather basically got the best of them. Napoleon realized that the weather was not good for them too late. Once they backed down, winter became their great major effect. He lost about 30,000 of his troops, and all because of the extremely low temperatures that led to diseases, and abandonment. Bad luck was what this basically was for Napoleon. This all influenced their great loss. The Russians managed to defeat the undefeated and invincible military genius that Napoleon was, and all for the smallest wrong move. Napoleon was replaced by Louis the 18th after this incident. He was banished to Elba, an island in the Mediterranean sea. Napoleon did not give up so easily. He managed to escape Elba, and yet make the last mistake he needed to literally complete his fall. Napoleon was so captivated by his failures that he decided to prove others wrong, that he can be that military genius everyone knew about. But, all did not go so well. Napoleon governed what was known as the Hundred Days War. This war led them to a place called Waterloo, where the definite battle of the campaign took place. After three days in Waterloo, Napoleon decided he couldn’t go any longer. He had never given up before, but he realized he had nothing. He was an outlaw, and many were against him. His troops were growing smaller and smaller, as attacks kept on coming in, and there was no sense in victory for him. This is when Napoleon Bonaparte finally decided to surrender himself to the British Captain Frederick Maitland. Napoleon was then exiled to the island of Saint Helena where he later died on May of 1821. His mistake was, the fact that he still went back to fight, when he could have just surrendered in the first place. Bonaparte was indeed a great man, and he still had the reputation of the great Military genius, but his force did not let him be the good man he once was. Bonaparte committed many mistakes that simply shouldn’t have happened. These three major mistakes are just three in a variety of small others. Ambition and obsession never leads to any good. Napoleon had to learn that the hard way. Napoleon Bonaparte free essay sample A Military Genius Carlos Sahagun Cordova High School Franklin Per. 3 January 31, 2013 Sahagun 2 Napoleon Bonaparte Napoleon Bonaparte I chose Napoleon Bonaparte because he is one of the greatest military leaders that has ever lived. As a child, Napoleon excelled in military school and was always ahead of the game. At an early age of 10, Napoleon was accepted into the French Military School of Aristocrats. From there on he came to be one of the most successful and brilliant military leaders of all time. Sahagun 3 Napoleon Bonaparte Napoleon Bonaparte: A Military Genius Napoleon Bonaparte was born on August 14 of 1769 in the Corsican city of Ajaccio. He was the fourth child out of eleven. Napoleon’s father was a member of a well known, noble family. Napoleon began his military education at a young age of ten in 1779. He started his educational career at the French Military School of Aristocrats. He then transferred to the College of Brienne. We will write a custom essay sample on Napoleon Bonaparte or any similar topic specifically for you Do Not WasteYour Time HIRE WRITER Only 13.90 / page A more difficult, sophisticated school. While studying at the College of Brienne, he was made fun of for his lower social class and the disability of not being able to speak French very well and his small body. They called him â€Å"little corporal†. Although he had to live with unsupporting peers every day, he was always above everyone. When French officials saw his talent, he was promoted and turned into a Second Lieutenant for the French army in 1785. In 1792, he was in a power struggle between the opposing forces of Pasquale Paoli. This was a struggle for the independence of Corsica. When Paoli was successful, he forced Napoleon and his family to go back to France. As a result of defeat, Napoleon started his new military career in France. He unknowingly started the French Revolution when he defeated the British at the battle of Toulan and regained control of Corsica again. He then moved into Paris and overthrew King Louis the 16th. Soon after, Napoleon was winning battle after battle Sahagun 4 Napoleon Bonaparte against Prussian, Russian, English, Austrian, and Swiss armies. Napoleon was later named first consul, or leader of the government. Soon after he was named Emperor of France. As emperor, Napoleon improved living conditions in France significantly. He established a Bank of France, redesigned education, and created a new legal system known as the Code Napoleon. By 1802, Napoleon was given the political position of First Consul for life. In 1805, the British destroyed the French in a naval battle known as â€Å"The Battle of Trafalgar†. That was the beginning of Napoleon’s fall from power. When the British destroyed the French they lost many battleships to England. As an act to regain control, Napoleon introduced the Continental System. A blockade that was set around the borders of what he controlled. His intentions were to stop all trade with England and weaken England financially. It was a terrible failure. Almost every trading post ignored their orders and kept trade going. In Spain in 1808, the Peninsular War broke out when Spain denied Napoleon’s brother Joseph as king. At the same time, Russia broke peace with Napoleon after breaking the Continental System’s rules. As a result Napoleon decided to invade Russia and attempt to  take control of it. This was Napoleon’s worst mistake. Lack of supplies, disease, and cold weather killed 500,000 of Napoleon’s men. When he returned to Paris, Britain, Prussia, Austria, and Sweden formed a coalition against him and defeated him. He got exiled to the island of Elba. Meanwhile in France, King Louis the 16th’s brother, King Louis the 17th, was called to the Sahagun 5 Napoleon Bonaparte throne. When Napoleon found out what was happening in France he escaped from the island of Elba and landed in southern France. With an army of 1,500 soldiers he marched to Paris gaining more men as he went along. As word flew across France, Britain and Prussia found out and they formed another coalition against Napoleon. At the Battle of Waterloo, Napoleon was defeated once again and forced to step down a second time. He was then exiled to the small island of St. Helena in the southern part of the Atlantic Ocean. There he spent the rest of his life until he died of cancer on May 5th of 1821. Napoleon Bonaparte is classified as the best military leader of all time by many historians. No matter what the circumstances were every time, he never gave up. He was always ready for battle and never afraid of anything. Napoleon was a great military leader, politician, and last but most definitely not least, a great person. He lived in the hearts of the French who believed in him, and he now lives in all the hearts of the French who adore all his efforts that brought France their independence. Sahagun 6 Napoleon Bonaparte References Napoleon Bonaparte Biography. (2013). Advameg, Inc. Retrieved from http://www. notablebiographies. com/Mo-Ni/Napoleon-Bonaparte. html

More You Should Know about Hercules

More You Should Know about Hercules What You Should Know About Hercules | More You Should Know About Hercules | 12 Labors Hercules (Greek: Heracles/Herakles) Basics: Hercules was Apollo and Dionysus half-brother through their father Zeus. Disguised as Amphitryon, Zeus paid a conjugal visit to Amphitryons wife, Hercules mother, the Mycenaean princess Alcmene. Hercules and his twin, mortal, half-brother Iphicles, son of Alcmene and the real Amphitryon, were in their cradle when a pair of snakes visited them. Hercules happily strangled the snakes, possibly sent by Hera or Amphitryon. This inaugurated an extraordinary career that included the well-known 12 labors Hercules performed for his cousin Eurystheus. Here are more of Hercules feats with which you should be familiar. Education Hercules was talented in many areas. Castor of the Dioscuri taught him to fence, Autolycus taught him to wrestle, King Eurytus of Oechalia in Thessaly taught him archery, and Orpheus brother Linus, son of Apollo or Urania, taught him to play the lyre. [Apollodorus.] Cadmus is usually attributed with introducing letters into Greece, but Linus taught Hercules, and the not very academically inclined Hercules broke a chair over Linus head and killed him. Elsewhere, Cadmus is credited with killing Linus for the honor of introducing writing to Greece. [Source: Kerenyi, Heroes of the Greeks] Hercules and the Daughters of Thespius King Thespius had 50 daughters and wanted Hercules to impregnate them all. Hercules, who went hunting with King Thespius each day, was unaware that each nights woman was different (although he may not have cared), and so he impregnated 49 or 50 of them. The women gave birth to 51 sons who are said to have colonized Sardinia. Hercules and the Minyans or How He Acquired His First Wife The Minyans were exacting a heavy tribute from Thebes the usually cited birthplace of the hero while it was ruled by King Creon. Hercules encountered the Minyan ambassadors en route to Thebes and cut off their ears and noses, made them wear their bits as necklaces, and sent them back home. The Minyans sent retaliatory a military force, but Hercules defeated it and freed Thebes from the tribute. Creon rewarded him with his daughter, Megara, for his wife. The Augean Stables Reprised, With Dishonor King Augeas had refused to pay Hercules for cleaning his stables during the 12 Labors, so Hercules led a force against Augeas and his twin nephews. Hercules contracted a disease and asked for a truce, but the twins knew it was too good an opportunity to miss. They continued to try to annihilate Hercules forces. When the Isthmian Games were about to begin, the twins set out for them, but by this time, Hercules was on the mend. After dishonorably attacking and killing them, Hercules went to Elis where he installed Augeas son, Phyleus, on the throne in place of his treacherous father. More Hercules Dishonor Madness Euripides tragedy Hercules Furens is one of the sources for the madness of Hercules. The story, like most of those involving Hercules, has confusing and contradictory details, but in essence, Hercules, returning from the Underworld in some confusion, mistook his own sons, ones he had with Creons daughter Megara, for those of Eurystheus. Hercules killed them and would have continued his murderous rampage had Athena not lifted the (Hera-sent) madness or ate. Many consider the 12 Labors Hercules performed for Eurystheus his atonement. Hercules may have married Megara to his nephew Iolaus before leaving Thebes forever. Hercules Fight With Apollo Iphitus was the son of Apollos grandson Eurytus, who was the father of the beautiful Iole. In Book 21 of the Odyssey, Odysseus obtains the bow of Apollo when he helps in the hunt for Eurytus mares. Another part of the story is that when Iphitus came to Hercules looking for the missing dozen mares, Hercules welcomed him as a guest, but then hurled him to his death from a tower. This was another dishonorable murder for which Hercules needed to atone. The provocation may have been that Eurytus denied him the prize of his daughter, Iole, that Hercules had won in a bow-shooting contest. Possibly in search of atonement, Hercules arrived at the sanctuary of Apollo at Delphi, where as a murderer he was denied sanctuary. Hercules took the opportunity to steal the tripod and cauldron of Apollos priestess. Apollo came after him and was joined by his sister, Artemis. On Hercules side, Athena joined the fight. It took Zeus and his thunderbolts to put an end to the fighting, but Hercules still hadnt made atonement for his act of murder. Apollo, Asclepius, and Admetus On a related note, Apollo and Hercules both confronted Laomedon, an early king of Troy who refused to pay either Apollo or Hercules. Hercules and Omphale For atonement, Hercules was to endure a similar term to the one Apollo had served with Admetus. Hermes sold Hercules as a slave to the Lydian queen Omphale. In addition to getting her pregnant and tales of transvestism, the story of the Cercopes and the Black-bottomed Hercules comes from this period. Omphale (or Hermes) also set Hercules to work for a treacherous robber named Syleus. With wanton vandalism, Hercules demolished the thiefs property, killed him, and married his daughter, Xenodike. Hercules Last Mortal Wife Deianeira The final phase of Hercules mortal life involves his wife Deianeira, daughter of Dionysus (or King Oineus) and Althaia. Exchange and the Maiden When Hercules was taking his bride home, the centaur Nessus was to ferry her across the Euenos River. The details are varied, but Hercules shot Nessus with poisoned arrows when he heard the screaming of his bride being ravaged by the centaur. The centaur persuaded Deianeira to fill her water jug with blood from his wound, assuring her it would be a potent love potion when next Hercules eye started to wander. Instead of being a love potion, it was a potent poison. When Deianeira thought Hercules was losing interest, preferring Iole to herself, she sent him a robe drenched in the centaurs blood. As soon as Hercules put it on his skin burned intolerably. Poisoned Clothing Hercules wanted to die  but was having trouble finding someone to set his funeral pyre alight so he could self-immolate. Finally, Philoctetes or his father agreed and received Hercules bow and arrows as a thanks offering. These turned out to be essential weapons required by the Greeks to win the Trojan War. As Hercules burned, he was taken to the gods and goddesses where he gained full immortality and Heras daughter Hebe for his final wife. Philoctetes - The Difficult PatientBulfinch: Hercules - Hebe and GanymedeDeath of Hercules

The best references to give on a job application

The best references to give on a job application Your job references aren’t just warm bodies who can verify that you’re â€Å"the best employee ever, and a totally great fit for [insert job here].† If done thoughtfully, your references can help you create a specific â€Å"hire me because I have these skills† narrative, or support the one you’ve set up in your cover letter, resume, and interview. The groundwork for these references should be done ahead of time, before you even think about applying for a job. That way, they’re ready to go when you need them- and won’t be taken by surprise when someone calls them for a reference. So who should be included on your list of professional references?Your current bossThis is complicated if you’re looking for jobs on the down-low, but if it’s an open concept that you’re leaving your current job and looking for a new one, your current manager is the best bet. He or she knows you as you are right now and can speak to recent accomplishments. Before you offer up your current boss, though, it’s important to know roughly what they’ll say. If there are any concerns or uneasiness about that, then leave them off the list.Your current colleaguesThis can be a great alternative if you don’t want your current boss to know you’re actively seeking another job. A trusted colleague (one who can keep a secret) who works closely with you can be an excellent reference to have, since they know you in a day-to-day professional capacity. Ask him or her to talk about specific projects and what you’re like as a team member.Your former supervisorAn old boss can be useful because they can give the hiring manager a sense of what you’re like as an employee, but the risk here is that their professional information about you may be a little out of date. And as with referring your current boss, it’s important to know roughly what they’re going to say. If you think they might w ant to talk about some of your less-than-stellar moments, then think twice about including them.Your teachers or advisorsThis isn’t all that helpful if you’ve been in the workforce for a while, but if you’re a recent grad or just starting out, professors or advisors can tell the company about your skills and personality.Once you’ve decided who your go-to references are for this job application, be sure to give them a heads-up that they may be contacted. Also give them information about the job itself and what you’re hoping they’ll emphasize in their chat with the new company. There’s only so much you can stage-manage what this person will say, but giving them a template of sorts helps them prepare and find the most useful information to share about you. It takes some of the onus off of them to figure out what they’re supposed to talk about.It’s also important to make sure your references are targeted to the job you want. If you’re applying for a marketing job, your old boss at your summer restaurant job might not be the most useful person to help you get this new gig. The more thought and preparation you put into your reference list, the better and more focused information they’ll be able to provide.

To investigate how iPhone maker Apple competes across the Smartphone Dissertation

To investigate how iPhone maker Apple competes across the Smartphone market - Dissertation Example The marketing of the iPhone was done in tandem with the branding that Apple had in place, providing a platform from which to launch the revolutionary product. This study will look at the ways in which the market has been cornered by the product and what ways the perception of the product affects its popularity. Through the use of the grounding theory, a primary study has been made with a participant group of fifty users of Smartphones. Through the information provided by the questionnaire, the popularity of the iPhone has been examined and the ways in which it was successfully marketed has been explored. Table of Contents Abstract Table of Contents Chapter One: Introduction 1.1 The Marketing and Demand for the iPhone 1.2 Challenges presented by the iPhone within the Market 1.3 Research Objectives 1.3.1 To evaluate the effectiveness of the marketing strategy used by Apple 1.3.2 To investigate the quality and usability of product by Apple 1.3.3 To determine the outcome of customer sati sfaction with the Apple iPhone 1.4 Research Questions 1.4 Overview of Chapters Chapter Two Literature Review 2.1 Introduction 2.2 Smartphone Technology 2.3 The iPhone Release 2.4 Marketing Strategy 2.5 Competition in the UK Market 2.6 Chapter Summary Chapter Three: Methodology 3.1 Overall Research Plan 3.2 Research Design 3.3 Population and Sampling Size 3.3.1 Population 3.3.2 Sampling 3.4 Data Collection 3.4.1 Primary Data 3.4.1.1 Data Collection Methods 3.4.1.2 Pilot Study 3.4.1.3 Data Collection Time Table 3.4.2 Secondary Data 3.5 Data Analysis 3.6 Research Limitations 3.7 Chapter Summary Chapter Four: Data and Analysis 4.1 Introduction 4.2 Profile of the Respondents 4.3 Findings 4.4 Analysis Chapter Five: Conclusion and Recommendations 5.1 Introduction 5.2 Theoretical Implications 5.3 Managerial Implications 5.4 Limitations of the Study 5.5 Future Direction of Research 5.6 Summary References Appendix 1 Appendix 2 The iPhone: A study on the marketing strategies and the perception s of consumers about the Apple iPhone Chapter One: Introduction 1.1 The Marketing and Demand for the iPhone In the last decade, the creation of Smartphone technology has revolutionized the communications business. One of the initial products that was brought out into the public was the Apple iPhone. This product created a sensation that has yet to be rivaled by any other communications product to date. It hit the market with such force that it was sold out quickly and was on backorder for months after its release. The deal that Steve Jobs made with AT&T meant that only one wireless provider would have the product, thus creating a demand for AT&T service, but creating a necessity for other manufacturers to rush to mimic the product so other providers could carry the same type of communication advantages. In the UK, the iPhone can be used with a number of providers. According to the Apple website, prepaid service with Vodafone and Orange is available, along with service on monthly pla ns from O2, Orange, T-Mobile, Three, and Vodaphone (Apple 2011). The iPhone is the most used form of Smartphone technology within the UK. Through this study, the iPhone will be researched in order to discover why this phone has this depth of popularity and how the marketing has contributed to its large market share. 1.2 Challenges presented by the iPhone within the Market The iPhone is a revolution in the communications industry, creating an elite consumer who has a product that is in high

An American childhood by Annie dillard Essay Example | Topics and Well Written Essays - 500 words

An American childhood by Annie dillard - Essay Example eams through her mention of her father who painfully decided to give up his personal dreams to protect his family from the dangers of what would come from the talk of the people. Her adoration of the man with principles he stood for may not have been directly pointed out but they were clearly expressed as the writer saw through the eyes of a child. She spoke about her mother in a childlike manner, telling the story just how it happened, without sugar-coating rather in a child’s innocence; she placed her mother in the rightful pedestal. The story is a craftily written piece of art which engages the readers, making alive the actions, people and places mentioned. Probably the greatest ingredient used in the story that really grips the readers to stick their noses on the book until the end, is the honesty and innocence of the child in the grown-up Annie. Along with this, she made alive the story with her wit as she used professional means of story telling like figures of speech. Alliteration was used, with the repetition of sounds as the story is told, to put emphasis on some parts of the story, drawing attention from the reader for one to meditate more on it or analyze the meaning of which. An example for this is the line, â€Å"There was no messiness in her, no roughness for things to cling to, only a charming and charmed innocence that seemed then to protect her, an innocence I needed but couldn’t muster†. She used metaphors as well bringing life to some things she mentioned in the story as she viewed them during her childhood. She made the icebox motor talk in the line; â€Å"You are living†, the icebox motor said. In an interesting manner, her childhood imaginations were drawn before the eyes of her readers and this simply made the story more enjoyable. Even the figurative languages the author used in her story showed the genius in her as she realized as a child the essence of the stories he read or heard to the facts she observed. Metaphorically, the child

Hydrogels for Wound Healing Applications

Hydrogels for Wound Healing Applications Abstract This chapter discusses about the hydrogels both natural and synthetic that can be used for wound healing applications. Also it discusses briefly about the various novel techniques that have been developed recently. Keywords: Hydrogels; Chitosan, Antimicrobial; Grafting; Blending; Wound dressing; Wound healing; Gene therapy, Stem cell therapy, Skin Engineering, pH and Thermosensitive polymers. 1 Introduction Healthcare is an essential aspect of human survival. So many biopolymers have generated interest in a number of biomedical applications. Wound management is one such area where management of cuts, ulcers, and sores needs dressings which help in promoting rapid wound healing in order to obtain both functional and cosmetic results. [45] There are different kinds of wound management products: staples or sutures, dressings or bandages, surgical sealants and adhesives, skin substitutes, and other biomaterials. [51] Human skin provides an effective barrier to microbial penetration and subsequent infection. However, once the wound has been developed in this barrier, the infection chances increases. In case of chronic wounds, the colonization and infection potential increases as the result of the presence of avascular eschar which provides an environment for the uninhibited growth of microorganisms. [89] The rate of infection is related to the type of wound, general wound care, and local health of the patient. [88, 90] For avoiding infection, good clinical practices are needed. The management of chronic wounds is a very costly practice and it also places an enormous drain on healthcare resources; studies have calculated the cost of wounds to the NHS to be about  £1bn a year. [166] So for lowering this cost such wound management products are needed that are more economical and effective. Out of all the above wound management products, here in this chapter we will discuss more about the wound dressings that will provide an optimal healing environment to the wound. A dressing is an adjunct used by a person for application to a wound in order to promote healing and/or prevent further harm. It is designed to be in direct contact with the wound, so it is different from the bandage in the manner that bandages are normally used to hold dressing in place. A wound is a break in the epithelial integrity of the skin and may be accompanied by disruption of the structure and function of underlying normal tissue. Wounds can be divided into four categories based on their appearance and stage of healing: Necrotic, sloughing, granulating and epithelializing wounds. [87] Wounds cause discomfort and are more prone to infection and other troublesome complications. [75] Some diseases like diabetes, ischaemia and conditions like malnourishment, ageing, local infection, local tissue damage due to burn leads to delay in wound healing. Infection is a major complication of burn injury and is responsible for 50-75% of hospital deaths. [76] Human skin has one of the greatest capacities to regenerate itself amongst all of the tissues in our body. It constantly replaces old cells with new cells, enabling it to repair itself when damaged. Wound healing is a complex-physiologic process, which consists of three overlapping phases: inflammatory, proliferative and remodeling phases. The normal healing response begins the moment the tissue is injured. As the blood components spill into the site of injury, the platelets come into contact with exposed collagen and other elements of the extracellular matrix. This contact triggers the platelets to release clotting factors as well as essential growth factors. During the inflammation process, neutrophils are the first leukocytes which come at the site of injury to rid it from bacterial contamination. Then, the monocytes and their conversion to macrophages initiate tissue repair by releasing a number of biologically active substances and growth factors that are necessary for the initi ation of tissue formation process. In the third process, fibroblasts proliferate and migrate into the wound space and started the deposition of the loose extracellular matrix. Endothelial cells grow into a wound simultaneously with fibroblasts and undergo angiogenesis. Finally, tissue remodeling takes place to reconstruct the basement membrane by the differentiation of keratinocytes as well as the formation of follicle cells. [43, 49, 50] A scar is an essential part of this natural healing process following any type of damage to the skin. This can occur after a surgical incision or the healing of a wound. As your body makes an effort to close an open wound and protect itself from infection, it replaces injured skin tissue with rapidly generated scar tissue. Scarring is slight when the damaged outer layer of skin is healed by rebuilt tissue. When we damage the thick layer of tissue beneath the skin, rebuilding is more complicated. Our bodies lay down collagen fibers (a protein which is naturally produced by the body) and this usually results in a highly obvious scar. A permanent reminder of the injury is left behind. So, a dressing that can induce scarless healing is needed. Historically, a dressing was usually a piece of material, sometimes cloth, but the use of cobwebs, dung, leaves and honey has also been described. However, modern dressings include gauzes, semipermeable films, low adherent dressings, gels, foams, hydrocolloids, alginates, hydrogels and polysaccharide pastes. Wound dressings are passive, active or interactive. Passive dressings simply provide cover while active or interactive dressings are capable of modifying the physiology of the wound environment. Interactive dressings include hydrocolloids, hydrogels, alginates, foam dressings and antimicrobial dressings. [17, 20, 85] Traditionally dry wound dressings are considered to be good for healing wounds i.e. the wound should be covered with gauze or left open. But it has been observed by Winter [191] that when wound is left open to air without any dressing, a scab i.e. a dry covering covers the wound and decreases the rate of epithelialization. On the other hand, if moist dressing is used in place of dry dressings scab will not form and rate of healing increases as moist dressings provide low oxygen tension which helps in wound healing, these dressings not only keep cells viable which enables them to release growth factors while maintaining contact between them and the healing tissues, but may also modulate or stimulate their proliferation, these dressings decrease the pain at rest, during ambulation and during dressing changes also moist environment allows rapid and efficient delivery of any added antimicrobial agent thus prevent the wound from infection. So, the dressings that create and maintain a mois t environment, however, are now considered to provide the optimal conditions for wound healing. 2 Requirements of an ideal wound care system These characteristics should be present in the ideal wound care system (a) it should be capable of maintaining a high humidity at the wound site, (b) it should be non-toxic, (c) non-allergenic, (d) it can be removed without causing trauma to the wound, (e) it should pe impermeable to bacteria, (f) Thermally insulating, (g) it should be soft to touch, (h) it should allow proper gaseous exchange, (i) it should be free from particulate and toxic product, (j) promote tissue reconstruction processes and (k) it should be cost effective. [20, 165, 177] Out of all the dressings hydrocolloids, alginates and hydrogels each one has its own advantages and limitations but hydrogels are best and have all the characteristics that are needed in an ideal wound dressing. All the above mentioned characteristics can be achieved in hydrogel wound dressings. 3 Hydrogels for Wound Healing Applications Hydrogels are natural or synthetic cross-linked polymers used in a variety of medical and biomedical applications. Hydrogels consist of a matrix of insoluble polymers with up to 96% water content enabling them to donate water molecules to the wound surface and to maintain a moist environment at the wound bed. They are used in the construction of contact lenses, drug-delivery vehicles, wound dressings and as physiological electrodes or sensors. [17] Examples of hydrogel include Aquaform, Intrasite, GranuGel, Nu-Gel, Purilon, Sterigel. These also have the ability to absorb a degree of wound exudate. They transmit moisture vapour and oxygen, but their bacterial and fluid permeability is dependent on the type of secondary dressing used. [20] Hydrogels swell or shrink in aqueous solutions due to the association, dissociation and binding of various ions to polymer chains. These systems may swell in water until an equilibrium state is reached and retain their original shape. The interactions responsible for water sorption by hydrogels include the process of hydration, which is connected to the presence of such chemical groups as -OH, -COOH, -CONH2, -CONH-, and -SO3H and the existence of capillary areas and differences in osmotic pressure. The forces that make hydrogel dissolution impossible are presence of covalent bonds between individual polymer chains, hydrophobic and electrostatic interactions. [46] These are hydrophilic polymer networks which may absorb from 10-20% (an arbitrary lower limit) up to thousands of times their dry weight in water. These may be chemically stable or they may degrade and dissolve. They are called ‘reversible, or ‘physical gels when the networks are held together by molecular entanglements, and/or secondary forces including ionic, H-bonding or hydrophobic forces. [13, 14, 15] Hydrogels are called ‘permanent or ‘chemicalgels when they are covalently-crosslinked networks as shown in 1. Hydrogels can be made by irradiation, freeze-thawing or chemical methods. Out of all the methods, irradiation is considered as a suitable tool for the formation of hydrogels as in this method there is easy control of processing, no need of adding initiators or cross-linkers which are harmful, and have the possibility of formation and sterilization in one step. But as everything has its own advantages and disadvantages this method also has a disadvantage which is hydrogels formed by this method have poor mechanical strength. Nowadays, Freeze thawing technique is generally used to prepare hydrogels having good strength, stability and no crosslinkers and initiators. But the main disadvantage is that the prepared hydrogels have opaque appearance and limited swelling and thermal stability. [120] In comparison to the traditional gauze therapy the application of a hydrogel seems to significantly stimulate wound healing. [11] Various natural and synthetic polymers having good biocompatibility are used to develop hydrogel wound dressing. These polymers include natural polymers such as alginate, chitosan, gelatin and collagen and synthetic polymers such as polyurethane, poly(ethylene glycol), polycaprolactone, poly vinyl pyrrolidone, poly(lactide-co-glycolide), polyacrylonitrile , poly(amino acid), etc. Table 1 below shows different hydrophilic polymers used to synthesize hydrogel matrices. Table 1 Hydrophilic polymers used to synthesize hydrogel matrices. [13] Hydrogels may be classified as homopolymer hydrogels, copolymer hydrogels, multipolymer hydrogels, and interpenetrating polymeric hydrogels. Homopolymer hydrogels are crosslinked networks of one type of hydrophilic monomer unit, whereas copolymer hydrogels are produced by the crosslinking of two comonomer units, one of which must be hydrophilic. Multipolymer hydrogels are produced by the crosslinking of more than three monomers. Finally, interpenetrating polymeric hydrogels are produced by the swelling of a first network in a monomer and the reaction of the latter to form a second intermeshing network structure. [46, 47] Also, it has been shown that the blending of a natural polymer with a synthetic polymer seems to be a good method for obtaining materials having required mechanical and thermal properties in comparison to pure components. It is also a simple method by which suitable shapes such as films, sponges and hydrogels can be obtained easily to realize a variety of biomedical devices. 2 shows healing is faster with the hydrogel dressing than with the gauze dressing. Wound area covered by hydrogel decreases faster with increasing healing period. On the contrary, the wound covered by gauze dressing reduces by only half a percent even after 14 days. [192] 3.1 Natural Hydrogels Natural polymers, such as chitin, chitosan, alginate, collagen, elastin, genipin, gelatin, cellulose etc. have been used for dressing wounds because they play an important role in the healing process. [47] Chitosan is a partially deacetylated form of chitin. Chitin as BeschitinÃ’, Unitika, is also commercially available as dressing in Japan. [28] But as far as chitosan is concerned it is biocompatible, biodegradable, haemostatic, fungistatic [54] and non-toxic and can be successfully used as gels, films, fibres etc. This polymer also show antibacterial properties and possess good wound healing properties. [60, 61, 62] It has many applications as wound dressing, drug delivery device and as scaffold for tissue engineering. [63, 64] Some of the examples of wound dressings are given below which use chitosan as one of the biomaterial. Asymmetric chitosan membranes have been developed by using immersion-precipitation phase-inversion method. [123, 124, 125] These asymmetric chitosan membranes are homogeneous and have porous structure. This membrane was prepared by preheating casted chitosan solution in oven for different time periods for dry phase separation and then immersed in to coagulant tank for wet phase separation and were subsequently freeze-dried. The skin layer acts as the rate controlling barrier for the release of drug and the porous layer provide mechanical support to the skin layer. The water vapor transmission rate, gas permeability, PBS solution absorption, in-vitro degradation, cell culture, bacterial penetration and wound healing test of this dressing were carried out. These membranes are effective in controlling evaporative water loss, showed excellent oxygen permeability and also antibacterial in nature. These are also found to be an urgent hemostat. In another study, silver sulphadiazine was inc orporated as an antimicrobial agent to this asymmetric dressing. The release behaviour of both silver and sulphadiazine ions were studied and found to be significantly different from one another. Silver ions displayed a slow release behavior while sulphadiazine ions exhibited burst effect on first day of the drug release and then slowly tapered off. It is because of the interaction of silver with amino group of chitosan leading to its slow release throughout whereas, as the sulphadiazine ions were free to diffuse through the membrane to reach the wound site thus they showed a burst release. The membranes were further found effective against P. aerugniosa and S. aureus. In one of the papers, novel wound dressings were formed that composed of chitosan film and Minocycline Hydrochloride (MH) and commercial polyurethane film (Tegaderm) as a backing. It is also a useful formulation for the treatment of severe burn wounds. Water vapor and oxygen can permeate the Tegaderm film but water cannot. The tegaderm film support the polymer membrane. [126] In one of the studies, a silver nanocrystalline chitosan (SNC) wound dressing composed of nano-silver and chitosan was constructed by self-assembly and nanotechnology and used for treating deep partial-thickness wounds. In this, sterility and pyrogen testing were performed to ensure biosafety. These dressings promote wound healing and combat infection, and also decrease the risk of silver absorption in comparison with silver sulphadiazine (SSD) dressings. [127] There is also one more method of forming wound dressing composed of chitosan i.e. the formation of polyelectrolyte complex of gum kondagogu (GKG) and chitosan. This complex is formed by the electrostatic interaction between carboxyl group of gum and amine group of chitosan. This method is more advantageous as it avoids the use of organic solvents, chemical crosslinking agents and thus reduces the toxicity and undesirable side effects. In this, diclofenac sodium is used as model drug. The diclofenac loaded complex of gum kondagogu/ chitosan shows drug release which changes with change in pH. The drug release was higher at pH 6.8 as compared to pH 1.2, due to higher swelling of complex at higher pH. This holds a great potential as a natural polymer based delivery device for controlled delivery of drugs like diclofenac sodium for two reasons: (i) to reduce dosing frequency and (ii) lower the gastric toxicity. [152] Semi-interpenetrating polymer networks (SIPNs) composed of chitosan (CS) and poloxamer were prepared in order to improve the mechanical strength of CS. The WVTR was found to be 2508.2 ±65.7 gm−2 day−1, i.e. these can maintain a moist environment at wound site which enhance epithelial cell migration. Also, the in vitro assessment of SIPNs showed proper biodegradation and low cytotoxicity and in vivo is carried out on experimental full thickness wounds in a mouse model and found that the wounds covered with these were completely filled with new epithelium without any significant adverse reactions after 3 weeks. In one of the papers, a kind of surgical wound dressing, the chitosan-gelatin sponge wound dressing (CGSWD) having good antibacterial property is prepared. The in vitro test showed that the antibacterial effect of CGSWD on E. coli K88 is better than that of penicillin, and the effect on S. aureus is also better than that of cefradine. [137] One more wound dressing consists of two separate layers were prepared in which the upper layer is a swellable hydrogel material which can absorb exudates and also serve as mechanical and microbial barrier while lower layer is a chitosan acetate foam incorporated with the anti-microbial agent chlorherxidine gluconate. [183] The antimicrobial activity is checked by the Bauer-Kirby Disk Diffusion Test, inhibition zones can be clearly seen around the discs of chitosan acetate foams incorporated with chlorhexidine gluconate, in culture plates inoculated with either Gram-negative or positive bacteria showing that the dressing is antimicrobial in nature. Blending is a convenient and effective method to improve physical and mechanical properties of hydrogels. So modification of chitosan is done by blending with other polymers like cellulose. [178] In this, E. coli and S. aureus were used as the test bacteria to examine the antibacterial properties of chitosan, cellulose and chitosan/cellulose blends. The numbers of colony of these bacteria formed on the test membranes are shown in s 5 and 6. It was noted that the numbers of colony of all test bacteria formed on the chitosan/cellulose blend membranes were decreased with the increase of chitosan concentration. These blends are more effective against E. coli than that of S. aureus, as indicated by the lower colony unit. Thus these dressings are suitable to use as an antimicrobial wound dressing. Chitosan due to its structural properties has the ability to heal wounds without scar formation. [198] Since chitosan is composed of D-glucosamine, which is also the component present in the disaccharide subunits of hyaluronic acid, chitosan tries to structurally mimic hyaluronic acid and exerts similar effects. [197] It has been known that the fetal wound healing takes place without fibrosis or scar formation due to the presence of hyaluronic acid. [199] In one of the studies, Chitosan as a semi-permeable biological dressing maintains a moist environment and prevent the wound site from dehydration and contamination. In addition, digital colour separation analysis of donor site scars demonstrated an earlier return to normal skin colour at chitosan-treated areas as shown in 7. [196] Collagen is also a biopolymer that is used as a polymer for making wound dressing and drug delivery devices as it is biocompatible and biocompatibility of a material applied to wound tissue is a prerequisite for optimal wound environment and facilitation of the healing processes. A new collagen dressing with gentamycin or amikacin was prepared in one of the research work and these follow the basic requirement of antibacterial bandages. The dressing is composed of two collagen biomaterials—membrane and sponge—both possessing good tissue biocompatibility. These dressing released antibiotics slowly and show the antibacterial treatment in experimentally infected superficial wounds in mice. Thus, it can be used for the treatment of infected wounds in humans. [26] As discussed previously that both chitosan and collagen are excellent materials that can be used as wound dressing materials. So it has been seen that if both are used simultaneously then what will be the effect. It is found that the wound dressings composed of chitosan crosslinked collagen sponge (CCCS) enhance the diabetic wound healing. Collagen crosslinked with chitosan showed several advantages required for wound dressing, including the uniform and porous ultrastructure, less water imbibition, small interval porosity, and high resistance to collagenase digestion and slow release of FGF from CCCS/FGF. [138] Following moist healing concept, alginates which are able to absorb exudates from wound have become one of the most important materials for wound management. [52, 53, 54, 55, 56] In this particular field, the properties of alginate fibers are unparalleled in many respects. Alginate based products form a gel and effective in removing out of the wound on the contrary to traditional cotton and viscose fibres, which can entrap in the wound developing discomfort during dressing removal. [55] Also, the alginate fibres are non-toxic, non-carcinogenic, non-allergic, haemostatic, biocompatible, of reasonable strength, capable of being sterilized and easily processable. Sorbsanâ„ ¢ was first commercialized in 1981 and after that there were many dressings launched. The alginate fibers can be converted into wound dressings by using a number of textile processes. Because of its simplicity and also the high absorbency of the product, nonwoven is the main form of alginate wound dressings. [19] The antimicrobial action of alginate dressing can be seen as in 8 which shows the antimicrobial action of silver containing alginate fibers against E. Coli. There was 100% reduction in bacteria count within 5 hr after the fibers were placed in contact with solutions containing the bacteria. Sorbsan alginate fibers showed some antimicrobial activity while AquacelTM (made of carboxymethyl cellulose), does not show any antimicrobial effect. [18] Gelatin widely found in nature and is the major constituent of skin, bones, and connective tissue. Gelatin can easily be obtained by a controlled hydrolysis of the fibrous insoluble protein, collagen. [195] This is also used in number of biomedical applications like wound dressings. Hydrogel wound dressing from gelatin, oxidized alginate and borax were prepared and the composite matrix promotes wound healing because of alginate, has haemostatic effect of gelatin and is antiseptic because of borax. The water vapour transmission rate (WVTR) of the hydrogel was calculated and found to be 2686 ±124 g/m2/day indicating that this hydrogel can maintain a proper fluid balance at the wound site which helps in cell migration. 2 shows the loss of water vapour with time through the hydrogel when placed in a moisture rich environment. [119] Genipin has been used to crosslink chitosan membranes to control swelling ratio and mechanical properties. It increased its ultimate tensile strength but significantly reduced its strain-at-fracture and swelling ratio. It had significantly less cytotoxicity for human fibroblasts and slower degradation rate compared to the glutaraldehyde-crosslinked membrane. This genipin crosslinked chitosan membrane can be successfully used as a wound dressing. [132] Bacterial cellulose is a natural polymer consisting of microfibrils containing glucan chains bound together by hydrogen bonds. Bacterial cellulose with chitosan combines properties such as bioactivity, biocompatibility, and biodegradability of the two biopolymers and form an ideal material for dressing wounds. [66, 67] These are antibacterial and scar preventive in nature too. Since natural polymers have been considered limited in their applications for wound-dressing materials as their low mechanical properties and shortage of processing. So we move towards the synthetic polymers that can be used for wound healing applications. 3.2 Synthetic Hydrogels Synthetic polymers are also being used successfully in biomedical applications as one of the materials because of their wide range of mechanical properties, suitability for easily forming into a variety of different shapes, and low production costs. In an ideal dressing both the characteristics i.e. antimicrobial ability and moist healing environment should be present, so in order to prevent the wound from dehydration and bacterial penetration a new dressing composed of polyurethane is designed in such a way that the upper layer of the dressing is microporous (pore size Polyvinyl pyrrolidone (PVP) is one of the most widely used synthetic polymers in medicine because of its solubility in water and its extremely low cytotoxicity. Hydrogels prepared by radiation crosslinking of an aqueous solution of polyvinyl pyrrolidone (PVP) have been used as wound dressing. [21] These are biocompatible, reduces pain, easily replacable, permeable to oxygen, maintain moist environment at the wound site. Polyvinyl alcohol (PVA) is a well-known polymer because it is biocompatible and have required mechanical properties and polyethylene oxide (PEO) is a hydrophilic semicrystalline polyether which is biocompatible, non toxic, non polar, non antigenic and non immunogenic and is highly desirable in most biomedical applications requiring contact with physiological fluids. A hydrogel composed of PEO for wound dressing is prepared and PVA is added to give toughness to the hydrogel by electron beam irradiation and found that these hydrogels showed satisfactory properties for wound dressing that has been evaluated by creating wound on the back of the marmots. [157] The hydrogel gives a wet environment to wounds which causes faster healing compared with the gauze dressing with a dry environment. The weight of the hydrogel increases quickly at the earlier stages, up to 4 days, due to absorption of effusion produced from the wound as shown in Table 2. After that, the production of effusion from the wound ceases and the weight of the hydrogel decreases due to evaporation of the water in the hydrogel. This means that the healing of wound proceeds smoothly with time. The hydrogel can be peeled off easily from the wound at the time of removal. Table 2 Absorption of effusion from wound of dressing during healing. [157] The toughness of PEO hydrogel is improved by the addition of PVA and tensile strength is measured and found that as shown in 10 and 11, the tensile strength and elongation decrease with increasing dose because of the increase of crosslinking. Various synthetic polymers as discussed above are used for wound dressing applications. But the major problem with these materials is their biocompatibility characteristics are often unsatisfactory and their interaction with living tissues is a major problem. So a combination of both natural and synthetic polymers is the better option to make a hydrogel having biocompatibility and desired mechanical strength. 3.3 Blended hydrogels Since both the natural and synthetic polymers have their own advantages and disadvantages so a combination of natural and synthetic polymers can endow the optimal properties necessary for wound repair. [47] The combination of natural and synthetic polymers is used in the biomedical, bioengineering and biotechnology field nowadays because of their great potential. A blended hydrogel composed of polyvinyl alcohol/polyvinyl pyrrolidone and charcoal were prepared by single ‘‘freezing and thawing or two-step ‘‘freezing and thawing and ÃŽ ³-ray irradiation and applied as wound dressing. It is found that the absorption of S. aureus and P. aeruginosa by charcoal/PVA/PVP hydrogels was larger than those by PVA/PVP hydrogels, this is due to the absorption and attachment capability of bacteria by charcoal, this can be shown in 12 given below. [22] The most classical way of fabricating a CS based wound dressing has been to design an asymmetric composite structure. In this method, the Cotton fabric was coated with chitosan (CS) and polyethylene glycol (PEG) followed by freeze-drying. The outer dense layer helps in preventing the microbial passage across the dressing and provides a rate controlling barrier for water vapor permeation, while the inner porous layer provides a high surface area for the exudates absorption. For the absorption of wound exudates porosity is the prime requirement in a dressing. It has been found that these dressings have the porosity 54-70% and the pore size was in the range of 75-120 µm. [45] The increase in the PEG content in the blend composition led to an enhanced destabilization of pores, leading to an increase in the pore size with elongated morphology. There seems to be phase separation between the two components which is an important factor for the observed behavior of the porous structure. Cot ton fabric has been used as the support layer for the CS-PEG layer and leads to very thin and light weight structures. The structure of the dressing has been designed in such a way that it leads to the high porosity of the bulk structure. The thickness of CS coating plays an important role in the development of the porosity on the surface. The influence of the CS thickness on the surface morphology is presented in 13 given below. PEG addition to CS makes significant alteration in the surface morphology of this CS-PEG/cotton membrane (freeze-dried), henceforth known as CPC membrane. There is a distinct trend in the loss of inherent elongated porous structure in membranes and formation of the partially collapsed porosity takes place due to the PEG addition. This suggests that a very limited interaction between CS and PEG exists which is reflected in the observed surface morphology. It has been observed that higher the amount of PEG, the higher is the pore destabilization leading to larger pores. This is evident from the morphology of the CPC membrane at 50% PEG-20 content as shown in 14.45 On the above matrix, the addition of PVP and drug followed by coating on the cotton fabric and freeze drying of the coated matrix is also done. It has been found that the drug Hydrogels for Wound Healing Applications Hydrogels for Wound Healing Applications Abstract This chapter discusses about the hydrogels both natural and synthetic that can be used for wound healing applications. Also it discusses briefly about the various novel techniques that have been developed recently. Keywords: Hydrogels; Chitosan, Antimicrobial; Grafting; Blending; Wound dressing; Wound healing; Gene therapy, Stem cell therapy, Skin Engineering, pH and Thermosensitive polymers. 1 Introduction Healthcare is an essential aspect of human survival. So many biopolymers have generated interest in a number of biomedical applications. Wound management is one such area where management of cuts, ulcers, and sores needs dressings which help in promoting rapid wound healing in order to obtain both functional and cosmetic results. [45] There are different kinds of wound management products: staples or sutures, dressings or bandages, surgical sealants and adhesives, skin substitutes, and other biomaterials. [51] Human skin provides an effective barrier to microbial penetration and subsequent infection. However, once the wound has been developed in this barrier, the infection chances increases. In case of chronic wounds, the colonization and infection potential increases as the result of the presence of avascular eschar which provides an environment for the uninhibited growth of microorganisms. [89] The rate of infection is related to the type of wound, general wound care, and local health of the patient. [88, 90] For avoiding infection, good clinical practices are needed. The management of chronic wounds is a very costly practice and it also places an enormous drain on healthcare resources; studies have calculated the cost of wounds to the NHS to be about  £1bn a year. [166] So for lowering this cost such wound management products are needed that are more economical and effective. Out of all the above wound management products, here in this chapter we will discuss more about the wound dressings that will provide an optimal healing environment to the wound. A dressing is an adjunct used by a person for application to a wound in order to promote healing and/or prevent further harm. It is designed to be in direct contact with the wound, so it is different from the bandage in the manner that bandages are normally used to hold dressing in place. A wound is a break in the epithelial integrity of the skin and may be accompanied by disruption of the structure and function of underlying normal tissue. Wounds can be divided into four categories based on their appearance and stage of healing: Necrotic, sloughing, granulating and epithelializing wounds. [87] Wounds cause discomfort and are more prone to infection and other troublesome complications. [75] Some diseases like diabetes, ischaemia and conditions like malnourishment, ageing, local infection, local tissue damage due to burn leads to delay in wound healing. Infection is a major complication of burn injury and is responsible for 50-75% of hospital deaths. [76] Human skin has one of the greatest capacities to regenerate itself amongst all of the tissues in our body. It constantly replaces old cells with new cells, enabling it to repair itself when damaged. Wound healing is a complex-physiologic process, which consists of three overlapping phases: inflammatory, proliferative and remodeling phases. The normal healing response begins the moment the tissue is injured. As the blood components spill into the site of injury, the platelets come into contact with exposed collagen and other elements of the extracellular matrix. This contact triggers the platelets to release clotting factors as well as essential growth factors. During the inflammation process, neutrophils are the first leukocytes which come at the site of injury to rid it from bacterial contamination. Then, the monocytes and their conversion to macrophages initiate tissue repair by releasing a number of biologically active substances and growth factors that are necessary for the initi ation of tissue formation process. In the third process, fibroblasts proliferate and migrate into the wound space and started the deposition of the loose extracellular matrix. Endothelial cells grow into a wound simultaneously with fibroblasts and undergo angiogenesis. Finally, tissue remodeling takes place to reconstruct the basement membrane by the differentiation of keratinocytes as well as the formation of follicle cells. [43, 49, 50] A scar is an essential part of this natural healing process following any type of damage to the skin. This can occur after a surgical incision or the healing of a wound. As your body makes an effort to close an open wound and protect itself from infection, it replaces injured skin tissue with rapidly generated scar tissue. Scarring is slight when the damaged outer layer of skin is healed by rebuilt tissue. When we damage the thick layer of tissue beneath the skin, rebuilding is more complicated. Our bodies lay down collagen fibers (a protein which is naturally produced by the body) and this usually results in a highly obvious scar. A permanent reminder of the injury is left behind. So, a dressing that can induce scarless healing is needed. Historically, a dressing was usually a piece of material, sometimes cloth, but the use of cobwebs, dung, leaves and honey has also been described. However, modern dressings include gauzes, semipermeable films, low adherent dressings, gels, foams, hydrocolloids, alginates, hydrogels and polysaccharide pastes. Wound dressings are passive, active or interactive. Passive dressings simply provide cover while active or interactive dressings are capable of modifying the physiology of the wound environment. Interactive dressings include hydrocolloids, hydrogels, alginates, foam dressings and antimicrobial dressings. [17, 20, 85] Traditionally dry wound dressings are considered to be good for healing wounds i.e. the wound should be covered with gauze or left open. But it has been observed by Winter [191] that when wound is left open to air without any dressing, a scab i.e. a dry covering covers the wound and decreases the rate of epithelialization. On the other hand, if moist dressing is used in place of dry dressings scab will not form and rate of healing increases as moist dressings provide low oxygen tension which helps in wound healing, these dressings not only keep cells viable which enables them to release growth factors while maintaining contact between them and the healing tissues, but may also modulate or stimulate their proliferation, these dressings decrease the pain at rest, during ambulation and during dressing changes also moist environment allows rapid and efficient delivery of any added antimicrobial agent thus prevent the wound from infection. So, the dressings that create and maintain a mois t environment, however, are now considered to provide the optimal conditions for wound healing. 2 Requirements of an ideal wound care system These characteristics should be present in the ideal wound care system (a) it should be capable of maintaining a high humidity at the wound site, (b) it should be non-toxic, (c) non-allergenic, (d) it can be removed without causing trauma to the wound, (e) it should pe impermeable to bacteria, (f) Thermally insulating, (g) it should be soft to touch, (h) it should allow proper gaseous exchange, (i) it should be free from particulate and toxic product, (j) promote tissue reconstruction processes and (k) it should be cost effective. [20, 165, 177] Out of all the dressings hydrocolloids, alginates and hydrogels each one has its own advantages and limitations but hydrogels are best and have all the characteristics that are needed in an ideal wound dressing. All the above mentioned characteristics can be achieved in hydrogel wound dressings. 3 Hydrogels for Wound Healing Applications Hydrogels are natural or synthetic cross-linked polymers used in a variety of medical and biomedical applications. Hydrogels consist of a matrix of insoluble polymers with up to 96% water content enabling them to donate water molecules to the wound surface and to maintain a moist environment at the wound bed. They are used in the construction of contact lenses, drug-delivery vehicles, wound dressings and as physiological electrodes or sensors. [17] Examples of hydrogel include Aquaform, Intrasite, GranuGel, Nu-Gel, Purilon, Sterigel. These also have the ability to absorb a degree of wound exudate. They transmit moisture vapour and oxygen, but their bacterial and fluid permeability is dependent on the type of secondary dressing used. [20] Hydrogels swell or shrink in aqueous solutions due to the association, dissociation and binding of various ions to polymer chains. These systems may swell in water until an equilibrium state is reached and retain their original shape. The interactions responsible for water sorption by hydrogels include the process of hydration, which is connected to the presence of such chemical groups as -OH, -COOH, -CONH2, -CONH-, and -SO3H and the existence of capillary areas and differences in osmotic pressure. The forces that make hydrogel dissolution impossible are presence of covalent bonds between individual polymer chains, hydrophobic and electrostatic interactions. [46] These are hydrophilic polymer networks which may absorb from 10-20% (an arbitrary lower limit) up to thousands of times their dry weight in water. These may be chemically stable or they may degrade and dissolve. They are called ‘reversible, or ‘physical gels when the networks are held together by molecular entanglements, and/or secondary forces including ionic, H-bonding or hydrophobic forces. [13, 14, 15] Hydrogels are called ‘permanent or ‘chemicalgels when they are covalently-crosslinked networks as shown in 1. Hydrogels can be made by irradiation, freeze-thawing or chemical methods. Out of all the methods, irradiation is considered as a suitable tool for the formation of hydrogels as in this method there is easy control of processing, no need of adding initiators or cross-linkers which are harmful, and have the possibility of formation and sterilization in one step. But as everything has its own advantages and disadvantages this method also has a disadvantage which is hydrogels formed by this method have poor mechanical strength. Nowadays, Freeze thawing technique is generally used to prepare hydrogels having good strength, stability and no crosslinkers and initiators. But the main disadvantage is that the prepared hydrogels have opaque appearance and limited swelling and thermal stability. [120] In comparison to the traditional gauze therapy the application of a hydrogel seems to significantly stimulate wound healing. [11] Various natural and synthetic polymers having good biocompatibility are used to develop hydrogel wound dressing. These polymers include natural polymers such as alginate, chitosan, gelatin and collagen and synthetic polymers such as polyurethane, poly(ethylene glycol), polycaprolactone, poly vinyl pyrrolidone, poly(lactide-co-glycolide), polyacrylonitrile , poly(amino acid), etc. Table 1 below shows different hydrophilic polymers used to synthesize hydrogel matrices. Table 1 Hydrophilic polymers used to synthesize hydrogel matrices. [13] Hydrogels may be classified as homopolymer hydrogels, copolymer hydrogels, multipolymer hydrogels, and interpenetrating polymeric hydrogels. Homopolymer hydrogels are crosslinked networks of one type of hydrophilic monomer unit, whereas copolymer hydrogels are produced by the crosslinking of two comonomer units, one of which must be hydrophilic. Multipolymer hydrogels are produced by the crosslinking of more than three monomers. Finally, interpenetrating polymeric hydrogels are produced by the swelling of a first network in a monomer and the reaction of the latter to form a second intermeshing network structure. [46, 47] Also, it has been shown that the blending of a natural polymer with a synthetic polymer seems to be a good method for obtaining materials having required mechanical and thermal properties in comparison to pure components. It is also a simple method by which suitable shapes such as films, sponges and hydrogels can be obtained easily to realize a variety of biomedical devices. 2 shows healing is faster with the hydrogel dressing than with the gauze dressing. Wound area covered by hydrogel decreases faster with increasing healing period. On the contrary, the wound covered by gauze dressing reduces by only half a percent even after 14 days. [192] 3.1 Natural Hydrogels Natural polymers, such as chitin, chitosan, alginate, collagen, elastin, genipin, gelatin, cellulose etc. have been used for dressing wounds because they play an important role in the healing process. [47] Chitosan is a partially deacetylated form of chitin. Chitin as BeschitinÃ’, Unitika, is also commercially available as dressing in Japan. [28] But as far as chitosan is concerned it is biocompatible, biodegradable, haemostatic, fungistatic [54] and non-toxic and can be successfully used as gels, films, fibres etc. This polymer also show antibacterial properties and possess good wound healing properties. [60, 61, 62] It has many applications as wound dressing, drug delivery device and as scaffold for tissue engineering. [63, 64] Some of the examples of wound dressings are given below which use chitosan as one of the biomaterial. Asymmetric chitosan membranes have been developed by using immersion-precipitation phase-inversion method. [123, 124, 125] These asymmetric chitosan membranes are homogeneous and have porous structure. This membrane was prepared by preheating casted chitosan solution in oven for different time periods for dry phase separation and then immersed in to coagulant tank for wet phase separation and were subsequently freeze-dried. The skin layer acts as the rate controlling barrier for the release of drug and the porous layer provide mechanical support to the skin layer. The water vapor transmission rate, gas permeability, PBS solution absorption, in-vitro degradation, cell culture, bacterial penetration and wound healing test of this dressing were carried out. These membranes are effective in controlling evaporative water loss, showed excellent oxygen permeability and also antibacterial in nature. These are also found to be an urgent hemostat. In another study, silver sulphadiazine was inc orporated as an antimicrobial agent to this asymmetric dressing. The release behaviour of both silver and sulphadiazine ions were studied and found to be significantly different from one another. Silver ions displayed a slow release behavior while sulphadiazine ions exhibited burst effect on first day of the drug release and then slowly tapered off. It is because of the interaction of silver with amino group of chitosan leading to its slow release throughout whereas, as the sulphadiazine ions were free to diffuse through the membrane to reach the wound site thus they showed a burst release. The membranes were further found effective against P. aerugniosa and S. aureus. In one of the papers, novel wound dressings were formed that composed of chitosan film and Minocycline Hydrochloride (MH) and commercial polyurethane film (Tegaderm) as a backing. It is also a useful formulation for the treatment of severe burn wounds. Water vapor and oxygen can permeate the Tegaderm film but water cannot. The tegaderm film support the polymer membrane. [126] In one of the studies, a silver nanocrystalline chitosan (SNC) wound dressing composed of nano-silver and chitosan was constructed by self-assembly and nanotechnology and used for treating deep partial-thickness wounds. In this, sterility and pyrogen testing were performed to ensure biosafety. These dressings promote wound healing and combat infection, and also decrease the risk of silver absorption in comparison with silver sulphadiazine (SSD) dressings. [127] There is also one more method of forming wound dressing composed of chitosan i.e. the formation of polyelectrolyte complex of gum kondagogu (GKG) and chitosan. This complex is formed by the electrostatic interaction between carboxyl group of gum and amine group of chitosan. This method is more advantageous as it avoids the use of organic solvents, chemical crosslinking agents and thus reduces the toxicity and undesirable side effects. In this, diclofenac sodium is used as model drug. The diclofenac loaded complex of gum kondagogu/ chitosan shows drug release which changes with change in pH. The drug release was higher at pH 6.8 as compared to pH 1.2, due to higher swelling of complex at higher pH. This holds a great potential as a natural polymer based delivery device for controlled delivery of drugs like diclofenac sodium for two reasons: (i) to reduce dosing frequency and (ii) lower the gastric toxicity. [152] Semi-interpenetrating polymer networks (SIPNs) composed of chitosan (CS) and poloxamer were prepared in order to improve the mechanical strength of CS. The WVTR was found to be 2508.2 ±65.7 gm−2 day−1, i.e. these can maintain a moist environment at wound site which enhance epithelial cell migration. Also, the in vitro assessment of SIPNs showed proper biodegradation and low cytotoxicity and in vivo is carried out on experimental full thickness wounds in a mouse model and found that the wounds covered with these were completely filled with new epithelium without any significant adverse reactions after 3 weeks. In one of the papers, a kind of surgical wound dressing, the chitosan-gelatin sponge wound dressing (CGSWD) having good antibacterial property is prepared. The in vitro test showed that the antibacterial effect of CGSWD on E. coli K88 is better than that of penicillin, and the effect on S. aureus is also better than that of cefradine. [137] One more wound dressing consists of two separate layers were prepared in which the upper layer is a swellable hydrogel material which can absorb exudates and also serve as mechanical and microbial barrier while lower layer is a chitosan acetate foam incorporated with the anti-microbial agent chlorherxidine gluconate. [183] The antimicrobial activity is checked by the Bauer-Kirby Disk Diffusion Test, inhibition zones can be clearly seen around the discs of chitosan acetate foams incorporated with chlorhexidine gluconate, in culture plates inoculated with either Gram-negative or positive bacteria showing that the dressing is antimicrobial in nature. Blending is a convenient and effective method to improve physical and mechanical properties of hydrogels. So modification of chitosan is done by blending with other polymers like cellulose. [178] In this, E. coli and S. aureus were used as the test bacteria to examine the antibacterial properties of chitosan, cellulose and chitosan/cellulose blends. The numbers of colony of these bacteria formed on the test membranes are shown in s 5 and 6. It was noted that the numbers of colony of all test bacteria formed on the chitosan/cellulose blend membranes were decreased with the increase of chitosan concentration. These blends are more effective against E. coli than that of S. aureus, as indicated by the lower colony unit. Thus these dressings are suitable to use as an antimicrobial wound dressing. Chitosan due to its structural properties has the ability to heal wounds without scar formation. [198] Since chitosan is composed of D-glucosamine, which is also the component present in the disaccharide subunits of hyaluronic acid, chitosan tries to structurally mimic hyaluronic acid and exerts similar effects. [197] It has been known that the fetal wound healing takes place without fibrosis or scar formation due to the presence of hyaluronic acid. [199] In one of the studies, Chitosan as a semi-permeable biological dressing maintains a moist environment and prevent the wound site from dehydration and contamination. In addition, digital colour separation analysis of donor site scars demonstrated an earlier return to normal skin colour at chitosan-treated areas as shown in 7. [196] Collagen is also a biopolymer that is used as a polymer for making wound dressing and drug delivery devices as it is biocompatible and biocompatibility of a material applied to wound tissue is a prerequisite for optimal wound environment and facilitation of the healing processes. A new collagen dressing with gentamycin or amikacin was prepared in one of the research work and these follow the basic requirement of antibacterial bandages. The dressing is composed of two collagen biomaterials—membrane and sponge—both possessing good tissue biocompatibility. These dressing released antibiotics slowly and show the antibacterial treatment in experimentally infected superficial wounds in mice. Thus, it can be used for the treatment of infected wounds in humans. [26] As discussed previously that both chitosan and collagen are excellent materials that can be used as wound dressing materials. So it has been seen that if both are used simultaneously then what will be the effect. It is found that the wound dressings composed of chitosan crosslinked collagen sponge (CCCS) enhance the diabetic wound healing. Collagen crosslinked with chitosan showed several advantages required for wound dressing, including the uniform and porous ultrastructure, less water imbibition, small interval porosity, and high resistance to collagenase digestion and slow release of FGF from CCCS/FGF. [138] Following moist healing concept, alginates which are able to absorb exudates from wound have become one of the most important materials for wound management. [52, 53, 54, 55, 56] In this particular field, the properties of alginate fibers are unparalleled in many respects. Alginate based products form a gel and effective in removing out of the wound on the contrary to traditional cotton and viscose fibres, which can entrap in the wound developing discomfort during dressing removal. [55] Also, the alginate fibres are non-toxic, non-carcinogenic, non-allergic, haemostatic, biocompatible, of reasonable strength, capable of being sterilized and easily processable. Sorbsanâ„ ¢ was first commercialized in 1981 and after that there were many dressings launched. The alginate fibers can be converted into wound dressings by using a number of textile processes. Because of its simplicity and also the high absorbency of the product, nonwoven is the main form of alginate wound dressings. [19] The antimicrobial action of alginate dressing can be seen as in 8 which shows the antimicrobial action of silver containing alginate fibers against E. Coli. There was 100% reduction in bacteria count within 5 hr after the fibers were placed in contact with solutions containing the bacteria. Sorbsan alginate fibers showed some antimicrobial activity while AquacelTM (made of carboxymethyl cellulose), does not show any antimicrobial effect. [18] Gelatin widely found in nature and is the major constituent of skin, bones, and connective tissue. Gelatin can easily be obtained by a controlled hydrolysis of the fibrous insoluble protein, collagen. [195] This is also used in number of biomedical applications like wound dressings. Hydrogel wound dressing from gelatin, oxidized alginate and borax were prepared and the composite matrix promotes wound healing because of alginate, has haemostatic effect of gelatin and is antiseptic because of borax. The water vapour transmission rate (WVTR) of the hydrogel was calculated and found to be 2686 ±124 g/m2/day indicating that this hydrogel can maintain a proper fluid balance at the wound site which helps in cell migration. 2 shows the loss of water vapour with time through the hydrogel when placed in a moisture rich environment. [119] Genipin has been used to crosslink chitosan membranes to control swelling ratio and mechanical properties. It increased its ultimate tensile strength but significantly reduced its strain-at-fracture and swelling ratio. It had significantly less cytotoxicity for human fibroblasts and slower degradation rate compared to the glutaraldehyde-crosslinked membrane. This genipin crosslinked chitosan membrane can be successfully used as a wound dressing. [132] Bacterial cellulose is a natural polymer consisting of microfibrils containing glucan chains bound together by hydrogen bonds. Bacterial cellulose with chitosan combines properties such as bioactivity, biocompatibility, and biodegradability of the two biopolymers and form an ideal material for dressing wounds. [66, 67] These are antibacterial and scar preventive in nature too. Since natural polymers have been considered limited in their applications for wound-dressing materials as their low mechanical properties and shortage of processing. So we move towards the synthetic polymers that can be used for wound healing applications. 3.2 Synthetic Hydrogels Synthetic polymers are also being used successfully in biomedical applications as one of the materials because of their wide range of mechanical properties, suitability for easily forming into a variety of different shapes, and low production costs. In an ideal dressing both the characteristics i.e. antimicrobial ability and moist healing environment should be present, so in order to prevent the wound from dehydration and bacterial penetration a new dressing composed of polyurethane is designed in such a way that the upper layer of the dressing is microporous (pore size Polyvinyl pyrrolidone (PVP) is one of the most widely used synthetic polymers in medicine because of its solubility in water and its extremely low cytotoxicity. Hydrogels prepared by radiation crosslinking of an aqueous solution of polyvinyl pyrrolidone (PVP) have been used as wound dressing. [21] These are biocompatible, reduces pain, easily replacable, permeable to oxygen, maintain moist environment at the wound site. Polyvinyl alcohol (PVA) is a well-known polymer because it is biocompatible and have required mechanical properties and polyethylene oxide (PEO) is a hydrophilic semicrystalline polyether which is biocompatible, non toxic, non polar, non antigenic and non immunogenic and is highly desirable in most biomedical applications requiring contact with physiological fluids. A hydrogel composed of PEO for wound dressing is prepared and PVA is added to give toughness to the hydrogel by electron beam irradiation and found that these hydrogels showed satisfactory properties for wound dressing that has been evaluated by creating wound on the back of the marmots. [157] The hydrogel gives a wet environment to wounds which causes faster healing compared with the gauze dressing with a dry environment. The weight of the hydrogel increases quickly at the earlier stages, up to 4 days, due to absorption of effusion produced from the wound as shown in Table 2. After that, the production of effusion from the wound ceases and the weight of the hydrogel decreases due to evaporation of the water in the hydrogel. This means that the healing of wound proceeds smoothly with time. The hydrogel can be peeled off easily from the wound at the time of removal. Table 2 Absorption of effusion from wound of dressing during healing. [157] The toughness of PEO hydrogel is improved by the addition of PVA and tensile strength is measured and found that as shown in 10 and 11, the tensile strength and elongation decrease with increasing dose because of the increase of crosslinking. Various synthetic polymers as discussed above are used for wound dressing applications. But the major problem with these materials is their biocompatibility characteristics are often unsatisfactory and their interaction with living tissues is a major problem. So a combination of both natural and synthetic polymers is the better option to make a hydrogel having biocompatibility and desired mechanical strength. 3.3 Blended hydrogels Since both the natural and synthetic polymers have their own advantages and disadvantages so a combination of natural and synthetic polymers can endow the optimal properties necessary for wound repair. [47] The combination of natural and synthetic polymers is used in the biomedical, bioengineering and biotechnology field nowadays because of their great potential. A blended hydrogel composed of polyvinyl alcohol/polyvinyl pyrrolidone and charcoal were prepared by single ‘‘freezing and thawing or two-step ‘‘freezing and thawing and ÃŽ ³-ray irradiation and applied as wound dressing. It is found that the absorption of S. aureus and P. aeruginosa by charcoal/PVA/PVP hydrogels was larger than those by PVA/PVP hydrogels, this is due to the absorption and attachment capability of bacteria by charcoal, this can be shown in 12 given below. [22] The most classical way of fabricating a CS based wound dressing has been to design an asymmetric composite structure. In this method, the Cotton fabric was coated with chitosan (CS) and polyethylene glycol (PEG) followed by freeze-drying. The outer dense layer helps in preventing the microbial passage across the dressing and provides a rate controlling barrier for water vapor permeation, while the inner porous layer provides a high surface area for the exudates absorption. For the absorption of wound exudates porosity is the prime requirement in a dressing. It has been found that these dressings have the porosity 54-70% and the pore size was in the range of 75-120 µm. [45] The increase in the PEG content in the blend composition led to an enhanced destabilization of pores, leading to an increase in the pore size with elongated morphology. There seems to be phase separation between the two components which is an important factor for the observed behavior of the porous structure. Cot ton fabric has been used as the support layer for the CS-PEG layer and leads to very thin and light weight structures. The structure of the dressing has been designed in such a way that it leads to the high porosity of the bulk structure. The thickness of CS coating plays an important role in the development of the porosity on the surface. The influence of the CS thickness on the surface morphology is presented in 13 given below. PEG addition to CS makes significant alteration in the surface morphology of this CS-PEG/cotton membrane (freeze-dried), henceforth known as CPC membrane. There is a distinct trend in the loss of inherent elongated porous structure in membranes and formation of the partially collapsed porosity takes place due to the PEG addition. This suggests that a very limited interaction between CS and PEG exists which is reflected in the observed surface morphology. It has been observed that higher the amount of PEG, the higher is the pore destabilization leading to larger pores. This is evident from the morphology of the CPC membrane at 50% PEG-20 content as shown in 14.45 On the above matrix, the addition of PVP and drug followed by coating on the cotton fabric and freeze drying of the coated matrix is also done. It has been found that the drug