Electrochemical Characterization of Bovine Serum Albumin Adsorption - Free Essay Example

Sample details Pages: 3 Words: 926 Downloads: 10 Date added: 2019/03/18 Category Analytics Essay Level High school Tags: Characterization Essay Did you like this example? Blood-material interactions are critical for the performance and biocompatibility of biomedical devices implanted in thousands of patients every day. When an implant is introduced into the body, protein adsorption and activation of complement proteins occur on the foreign surface [1-3] and a series of interactions happen [4], firstly, water molecules reach the surface of the implant and build a water shell around it on a time scale that is of the order of nanoseconds. The interaction of the water molecules with the surface of the implant is dependent on the surface properties of the kind of material the implant is made of. Don’t waste time! Our writers will create an original "Electrochemical Characterization of Bovine Serum Albumin Adsorption" essay for you Create order This property also determines which proteins and other molecules will adhere following the formation of the hydration shell. Secondly, from a few seconds to hours after implantation, the implant becomes covered in an adsorbed layer of proteins primarily present in the extracellular matrix. Thirdly, cells eventually reach the surface interacting through the protein covering; thus cell-surface interactions can be described as the interaction between cells and surface-bound proteins. This stage occurs from as early as minutes or up to days after implantation [4]. As the time after material implantation increases from a few hours to several days, adhesion and migration followed by differentiation of cells occur. This third stage is influenced by biological molecules (extracellular matrix proteins, cell membrane proteins and cytoskeleton proteins); the biophysical environment and the evolving material physicochemical characteristics at the surface (chemistry, nano and micro-topographies); and the released soluble products from the material and its micro-structure (porosity) [5, 6]. The fourth and final stage in the useful life of the implant, which can last from a few days (biodegradable suture) up to several decades (total hip replacement), is the continuing development of the early implant stages. Adverse responses (clots or fibrous capsule formation, for example) and implant failure can occur â€Å" processes that can result from material degradation or mineralization [4]. Thus, the initial protein adsorption onto a biomaterial surface plays a key role in how the body responds to an implanted biomaterial. Surface modifications are often intentionally made to the surface of implants in order to improve their functionality and biocompatibility. The future development of improved biomaterials and novel coating techniques looks towards promoting fast healing and integration to prevent implant failure. Protein adsorption is crucial in cell adhesion for tissue regeneration, even though frequent biofouling is seen as an undesirable process in some applications. Protein adsorption on biomaterial surface is therefore of interest for bioengineering research Human serum albumin (HSA), a globular protein, is the most abundant component of many biofluids, serving as the transport of various metabolites and the regulation of the osmotic pressure [7, 8]. Bovine serum albumin (BSA) is used for protein adsorption studies since its structure is similar to the HSA structure [9], with nearly the same isoelectric point [10, 11] and molecular weight [10] and also because of its low-cost. Albumin is important in biomedical applications as it has been identified on implants ex vivo [12, 13]. There are a few studies available in the literature on protein adsorption on nickel-titanium materials (nitinol) [14]. One of these, by Shabalovskaya on polished, chemically-etched, heat treated and electropolished nickel-titanium surfaces [15], suggested that the amount of albumin adsorbed should be proportional to the nickel surface content of the alloy. Michiardi et al. have established a correlation between protein adsorption and surface energy on oxidized nickel-titanium surfaces [16]. Moreover, Clarke et al. found that the surface roughness and hydrophobicity appeared to have no effect on albumin adsorption [17]. Herein, we coated nickel-titanium with two phenolic compounds: pyrogallol and tannic acid, a coating procedure previously developed by Messersmith et al. on different surfaces such as gold, titanium dioxide, stainless steel, and polytetrafluoroethylene [18]. Nickel-titanium has been coated here with phenolic compounds because these bio-inspired compounds have anti-inflammatory properties â€Å" they are anti-proliferative agents for normal re-endothelialisation, nontoxic to mammalian cells [18, 19]. Polyphenols are also able to scavenge reactive oxygen species likely to oxidatively damage endothelial cells. In the presence of a metal, phenolic compounds are capable of forming metal ion complexes producing chelate ions; and on a surface, they build thin adherent films that induce minor changes in surface roughness [18, 19]. In this study, BSA adsorption on phenolic coated nickel-titanium has been investigated by different electrochemical tests. Firstly, the open circuit potential analysis (OCP), this type of measurement provides information about the natural corrosion behavior of the system undisturbed by any external voltage or current source and, therefore, in the absence of induced corrosion effects [20]. The corrosion potentials (EOCP) reflect the composite results of electrochemical reactions taking place at the surface/solution interface. Therefore, the variation in the corrosion potential, with immersion time, can be employed to study the electrochemical processes. Secondly, electrochemical impedance spectroscopy (EIS) â€Å" EIS is a non-destructive sensitive technique enabling the detection of any changes occurring at the electrode/electrolyte interface by the study of the impedance of an electrochemical system considered as a function of the frequency of an applied AC wave [20]. The Nyquist p lots and Bode diagrams from spectra analyses allow understanding the processes that occur at the metal/electrolyte boundary before, during and after protein adsorption on an electrode surface by applying the equivalent electrical circuit approach. Additionally, the electron transfer-initiated chemical reactions at the interface surface / protein were assessed by cyclic voltammetry. Nickel ion release has also been studied to investigate the possible diffusion of ions on the adsorbed protein layer. The objective of this paper was to study the protein interaction on phenolic coated nickel-titanium surface and simulate its adsorption in a physiological environment. This information is of clinical importance for future implantable biomedical devices to minimize ailing and failing implants.

Animal Farm By George Orwell - 1433 Words

Samantha Taddei Mrs. Mantineo English I Honors May 29, 2017 Animals Farm Research Paper â€Å"All animals are equal, but some animals are more equal than others.† George Orwell’s novella Animal Farm. Orwell’s goal in writing Animal Farm was to illustrate the 1917 Russian Revolution, and depict a government more tyrannical and oppressive than the one it overthrew. The characters and the events in Animal Farm mirror the Russian Revolution. For example, in the novella Manor Farm is a representation of Russia. Whereas animals like Old Major, Napoleon, and Snowball stand for the important figures of that time. Farmer Jones is who is in charge and runs Manor farm. He is the embodiment of Tsar Nicholas II, who was at the time the ruler of†¦show more content†¦As well, Old Major and Marx’s ideas for animalism and communism got altered and changed by others shortly after their deaths. Just as Marx, Old Major is also believed to share similarities with Vladimir Lenin. Old Major is responsible for converting Manor Farm into Animal Farm, as Lenin was responsible for changing Russia into the U.S.S.R. Vladimir Lenin also founded the Bolshevik Party. The Bolsheviks were able to gain power as a result of taking advantage of the social and political situations going on in the country at the time. This resembles to how the animals were able to gain power by banding together to overthrow farmer Jones. After Old Major had died of old age, Snowball and Napoleon both rose to power. They were the Stalin and Trotsky of Animal Farm. They both had vital parts on the farm, but with both having different beliefs on how to rule, they disagreed constantly. Snowball wanted to carry out what Old Major had started, and wanted to spread Animalism all over the world. Unlike Snowball, Napoleon didn t want to follow the rules and ideas of Old Major. A huge resemblance between Animal Farm and the Russian Revolution are Napoleon and Snowball’s plans about the windmill. Snowball wants to use the windmill to generate electricity in which would free the animals from the struggle of hard labor on the farm. This resembles to how Trotsky wanted to spread communism all over the world. Rather than Stalin, who only wanted it to stayShow MoreRelatedAnimal Farm And George Orwell By George Orwell1034 Words   |  5 Pages Eric Arthur Blair, under the pseudonym of George Orwell, composed many novels in his lifetime that were considered both politically rebellious and socially incorrect. Working on the dream since childhood, Orwell would finally gain notoriety as an author with his 1945 novel Animal Farm, which drew on personal experiences and deeply rooted fear to satirically critique Russian communism during its expansion. Noticing the impact he made, he next took to writing the novel 1984, which similarly criticizedRead MoreAnimal Farm By George Orwell1397 Words   |  6 PagesAn important quote by the influential author of Animal Farm, George Orwell, is, â€Å"Every line of serious work that I have written since 1936 has been written, directly or indirectly, against totalitarianism.† George Orwell, a Democratic Socialist, wrote the book Animal Farm as an attack on the Communist country of Russia (â€Å"The Political Ideas of George Orwell,† worldsocialism.org). He had a very strong disliking of Communism and the Socialist party of Russia. However, he insisted on finding the truthRead MoreAnimal Farm, By George Orwell1545 Words   |  7 Pagesallow because an this elite institution of people often use this gear to dominate and oppress society. In George Orwell’s story, Animal Farm, Orwell demonstrates that education is a powerful weapon and is a device that can be used to at least one’s benefit. Living in a world where strength is a straightforward to benefit, the pigs quick use education to govern the relaxation of the animals on the farm to serve themselves worked to their advantage. This story in shows the underlying message that   firstRead MoreAnimal Farm by George Orwell1100 Words   |  4 PagesIntroduction: Widely acknowledged as a powerful allegory, the 1945 novella Animal Farm, conceived from the satirical mind of acclaimed author George Orwell, is a harrowing fable of a fictional dystopia that critiques the socialist philosophy of Stalin in terms of his leadership of the Soviet Union. Tired of their servitude to man, a group of farm animals revolt and establish their own society, only to be betrayed into worse servitude by their leaders, the pigs, whose initial virtuous intentionsRead MoreAnimal Farm By George Orwell1538 Words   |  7 PagesMecca Animal Farm The Russian Revolution in 1917 shows how a desperate society can be turned into a military superpower filled with terror and chaos. George Orwell uses his book, Animal Farm, to parallel this period of time in history. This book is an allegory of fascism and communism and the negative outcomes. The animals begin with great unity, working toward a common goal. The government then becomes corrupted by the temptations of power. George Orwell uses the characters in Animal Farm to showRead MoreAnimal Farm By George Orwell944 Words   |  4 Pageslegs(Orwell 132). He carried a whip in his trotter(Orwell 133). In the novel Animal Farm by George Orwell, animals have the ability to talk and form their own ethos, Animalism. Animal Farm is an intriguing allegory by George Orwell, who is also the author of 1984, includes many enjoyable elements. More knowledge of the author, his use of allegorical elements, themes, symbols, and the significance in the real world, allows the reader to get more ou t of this glance into the future. George OrwellRead MoreAnimal Farm by George Orwell1175 Words   |  5 PagesAn enthusiastic participant in the Spanish civil war in 1936, George Orwell had a great understanding of the political world and made his strong opinions known through his enlightening literary works, many of which are still read in our modern era. Inspired by the 1917 Russian Revolution and the failed society it resulted in, Animal Farm by George Orwell is an encapsulating tale that epitomises how a free utopian society so idealistic can never be accomplished. The novella exemplifies how influencesRead MoreAnimal Farm, By George Orwell876 Words   |  4 Pagesrebellious animals think no man means freedom and happiness, but they need to think again. The animals of Manor Farm rebel against the farm owner, Mr. Jones, and name it Animal Farm. The animals create Animalism, with seven commandments. As everything seems going well, two of the animals get into a rivalry, and things start changing. Food starts di sappearing and commandments are changed, and the power begins to shift. Father of dystopian genre, George Orwell writes an interesting allegory, Animal FarmRead MoreAnimal Farm, By George Orwell1089 Words   |  5 PagesIn George Orwell’s â€Å"Animal Farm†, the pigs as the farm leaders, use unknown language, invoke scare tactics and create specific laws, thereby enabling them to control other animals, to suit their greedy desires, and to perform actions outside their realm of power. Because of the pigs’ use of broad language, and the implementation of these tactics they are able to get away with avoiding laws, and are able to convince other animals into believing untrue stories that are beneficial to the pigs. The firstRead MoreAnimal Farm By George Orwell999 Words   |  4 PagesAnimal Farm Essay George Gurdjieff was an influential spiritual teacher in the early twentieth century. He references in the following quote that when one is uneducated he will always remain a slave. â€Å"Without self knowledge, without understanding the working and functions of his machine, man cannot be free, he cannot govern himself and he will always remain a slave.† (Gurdjieff) This ties in with how the animals are treated in George Orwell’s Animal Farm. Animal Farm is a novella about animals who

Death of a Salesman4 Essay Example For Students

Death of a Salesman4 Essay Willie Lowman is a character that most anyone can identify with. He hastwo sides to his life; On one side he creates an image of beingsuccessful, well liked, and bold. On the other side he feels old,unsuccessful, defeated and disliked. He maintains the successful imageto comfort his wife and friends. This veil of success becomes thinnerand thinner until he lingers between fantasy and reality of the cruelworld, often changing back and forth in the course of a conversation. The core of Willie^s slow painful demise into nothingness is based uponhis beliefs. Willie thinks that success is not what you know, but whohe knows and how well he is liked. These beliefs he instills in hissons, who find themselves adrift and meaningless just like theirfather. In addition Willie sees the world changing, and his owninability to change with it, will seal his fate. He misses the openland and the smell of flowers in the summer, the pollution and highrise apartments add to Wil! lies dismal existence. An example ofWillies shift from fantasy to reality is during his conversation withhis wife about the Chevy. He thinks the car is fantastic, the best everbuilt. Later he and his wife discuss some bills that were paid, andwhen told about the bill to get the Chevy^s carburetor fixed, he saysthat they ought to prohibit the manufacture of the car. Willie Lowman is finding himself less and less capable. He dreams ofmaking it big and has visions of Uncle Ben who gives him advice on howto get rich, but never the kind of advice Willie wants to hear. Willieis concerned about his image. He is a great showman who can brag andflaunt like the best of them, and as witness to the hard truth of hisfailure he continues to weave fairy tales and live in fantasy. Williewants his sons to be better off and more successful than him, but hehas already corrupted them, and they too claim achievements well beyondreality. Biff comes to the reality of his position in life in theopening of the play. He knows he is not cut out for the business world. Biff prefers to move back to Texas and work on a farm. Although herealizes working on the farm won^t make him successful, he knows thatit^s his calling in life. Happy who is fairly stable and comfortable inhis work, prefers to continue with the charade, and the deception so aslong as it! makes life easier for him. Although his sons will not besuccessful, I think Willie Lowman did the best he could. Willie is notto blame for his sons disappointments, although he has delayed theirsuccess by giving them false ideas about success. The family situation is that of the standard dysfunctional family. Themother is upset by her sons because they have no respect for Willie andshow no concern for his decline. Willie loves his wife, but oftenmistreats her, cuts he off in mid conversation and belittles her. Biffbegins to hate his father because of the constant pressure to succeed,along with his fathers adultery and abuse of his mother. However Biffstill cares very deeply for his father deep down inside. Willie^sfavorite son is Biff; however Biff is also a continual source ofdisappointment for his father because of his inability to asserthimself in the business world. Happy is most like his father in the waythat he much prefers fantasy over reality. Happy is willing to continuewith pretending everything is all right so as long as it makes lifeeasier. The conflict is Willie versus nature. Nature being theenvironment and Willies inability to change and conform to it^s dynamicand changing nature. The characters in this play are easily understoodbecause of their similarity to most people who find themselves washedup in this game called life. People watching the play can easilyidentify with these characters who represent the average working classfamily. Nobody wins in the end because it^s real life. The father killshimself, hoping that the insurance money will send his family on theirway to success; and in actuality the insurance money from his deathwill heal no wounds, or right any wrongs. .u902061797b95a56e4c7b1271f447bdf8 , .u902061797b95a56e4c7b1271f447bdf8 .postImageUrl , .u902061797b95a56e4c7b1271f447bdf8 .centered-text-area { min-height: 80px; position: relative; } .u902061797b95a56e4c7b1271f447bdf8 , .u902061797b95a56e4c7b1271f447bdf8:hover , .u902061797b95a56e4c7b1271f447bdf8:visited , .u902061797b95a56e4c7b1271f447bdf8:active { border:0!important; } .u902061797b95a56e4c7b1271f447bdf8 .clearfix:after { content: ""; display: table; clear: both; } .u902061797b95a56e4c7b1271f447bdf8 { display: block; transition: background-color 250ms; webkit-transition: background-color 250ms; width: 100%; opacity: 1; transition: opacity 250ms; webkit-transition: opacity 250ms; background-color: #95A5A6; } .u902061797b95a56e4c7b1271f447bdf8:active , .u902061797b95a56e4c7b1271f447bdf8:hover { opacity: 1; transition: opacity 250ms; webkit-transition: opacity 250ms; background-color: #2C3E50; } .u902061797b95a56e4c7b1271f447bdf8 .centered-text-area { width: 100%; position: relative ; } .u902061797b95a56e4c7b1271f447bdf8 .ctaText { border-bottom: 0 solid #fff; color: #2980B9; font-size: 16px; font-weight: bold; margin: 0; padding: 0; text-decoration: underline; } .u902061797b95a56e4c7b1271f447bdf8 .postTitle { color: #FFFFFF; font-size: 16px; font-weight: 600; margin: 0; padding: 0; width: 100%; } .u902061797b95a56e4c7b1271f447bdf8 .ctaButton { background-color: #7F8C8D!important; color: #2980B9; border: none; border-radius: 3px; box-shadow: none; font-size: 14px; font-weight: bold; line-height: 26px; moz-border-radius: 3px; text-align: center; text-decoration: none; text-shadow: none; width: 80px; min-height: 80px; background: url(https://artscolumbia.org/wp-content/plugins/intelly-related-posts/assets/images/simple-arrow.png)no-repeat; position: absolute; right: 0; top: 0; } .u902061797b95a56e4c7b1271f447bdf8:hover .ctaButton { background-color: #34495E!important; } .u902061797b95a56e4c7b1271f447bdf8 .centered-text { display: table; height: 80px; padding-left : 18px; top: 0; } .u902061797b95a56e4c7b1271f447bdf8 .u902061797b95a56e4c7b1271f447bdf8-content { display: table-cell; margin: 0; padding: 0; padding-right: 108px; position: relative; vertical-align: middle; width: 100%; } .u902061797b95a56e4c7b1271f447bdf8:after { content: ""; display: block; clear: both; } READ: The Hobbit Essay ThesisBibliography:

Running Head NOISE CONTROL; RADON AND UV-RADIATIO Essays - Health

Running Head: NOISE CONTROL; RADON AND UV-RADIATION TUI UNIVERSITY Timothy N. Tarrant Module 5: BHE 314 Environmental Health and Safety Dr. Rania Sabty-Daily 15 September 2008 Abstract The first purpose of this paper is to discuss the public health effects that may result in a community exposed to noise produced by a night club and to describe the restrictions you would I would recommend the city requires the new nightclub meets before granting an approval. The following scenario will be used: I have been notified that there is a case before City Council to approve a new nightclub in my neighborhood. The club owners have a reputation for being insensitive to those who live nearby in the community. The second purpose of this paper is to identify potential human health risks associated with living in a home where radon gas levels may be high. Additionally, I will identify methods available to test for radon gas in the home and list corrective/remediation measures that can be taken to reduce radon levels in the home. The following scenario will be used: Radon gas emits Alpha particles which may cause lung cancer if inhaled by an individual. Friends of yours are purchasing a new home in an area where you understand that radon gas may be common. NOISE CONTROL Almost everyone is familiar with water and air pollution and the environmental concerns associated with them. However, noise pollution is also of concern as our cities continue to grow at an alarming rate. It seams as if whenever you venture out into the public you are forced to endure a variety of community noises. Have you ever sat down to enjoy dinner or a movie and have been interrupted by the sound of a loud train or plane? Well, these deep rumblings are similar to the sounds that will be produced by the nightclub that wants to operate within our community. "Some types of indoor concerts and discotheques can produce extremely high sound pressure levels. Associated noise problems outdoors result from customers arriving and leaving. Outdoor concerts, fireworks and various types of festivals can also produce intense noise. The general problem of access to festivals and leisure activity sites often adds to road traffic noise problems. Severe hearing impairment may also arise from intense sound produced as music in headphones or from children's toys." (WHO, 1999) Hearing impairment is the most often thought about health effect from noise pollution; however, there is a variety of health effects on the human body associated with increased noise emissions that people don't think about. These effects include: stress, hypertension, changes in heart rate, hypercholesterolemia, and/or excessive secretion of hormones. Noise also disturbs sleep, upsets our mental health, and even poses a danger to childhood development. Arlene L. Bronzaft, a member of the New York's Council on the Environment, stated, "I get many calls related to noise and most assuredly these people are very much troubled by the noises, whether from a loud, noisy neighborhood bar or a neighbor who refuses to keep the stereo low. The anguish these people express clearly speaks to a "poorer stat of mind." (Bronzaft, 1996) People exposed to noise during the night often turn to the use of sedatives or sleeping pills to fall asleep. Individuals in the community that are especially prone to sleep disturbances from noises that may emanate from a nightclub include the elderly and shift workers. (WHO, 1999) My recommendations to the City Council would be to recommend approval of the license for the operation of the nightclub only if they comply with certain restrictions. First and foremost I would recommend that the club is designed to be soundproof to inside noise so that noise that escapes the club will be minimal to the community surroundings. Then, I would make it mandatory for the club to install limiters on all amplified systems to limit low frequency noise. Additionally, I would require that the club keep door to the entrance of the club closed unless patrons are actively entering or exiting the establishment and the club should provide 10 square feet of indoor waiting space for patrons waiting to gain access to the club. This will limit the amount of noise that actually escapes the club. "The Office of Occupational Health and Safety (OSHA) identifies 90 decibels (dB) based on an eight-hour time-weighted average (TWA) as the absolute "safe" level of noise exposure. This 90dB concentration is referred to as the OSHA Permissible Exposure Limit (PEL) for noise exposure. Any eight-hour TWA exceeding 90dB