Conjugation of the Spanish Verb Reír

The written accent on its final syllable makes reà ­r (to laugh) an unusual verb. But it is  still regularly conjugated in terms of pronunciation, although not spelling. Sonreà ­r (to smile) is conjugated in the same  way as reà ­r. So is freà ­r (to fry) with one exception—freà ­r has two past participles, freà ­do and frito. The latter is far more common. Two of the forms below, rio and riais, used to be spelled with an accent: rià ³ and rià ¡is, respectively. But the Royal Spanish Academy eliminated the accents marks, which did not affect pronunciation, during a spelling overhaul in 2010. You may still see the accented forms in use. Irregular forms are shown below in boldface. Translations are given as a guide and in real life may vary with context. Infinitive of Reà ­r reà ­r (to laugh) Gerund of Reà ­r riendo (laughing) Participle of Reà ­r reà ­do (laughed) Present Indicative of Reà ­r yo rà ­o, tà º rà ­es, usted/à ©l/ella rà ­e, nosotros/as reà ­mos, vosotros/as reà ­s, ustedes/ellos/ellas rà ­en (I laugh, you laugh, he laughs, etc.) Preterite of Reà ­r yo reà ­, tà º reà ­ste, usted/à ©l/ella rio, nosotros/as reà ­mos, vosotros/as reà ­steis, ustedes/ellos/ellas rieron (I laughed, you laughed, she laughs, etc.) Imperfect Indicative of Reà ­r yo reà ­a, tà º reà ­as, usted/à ©l/ella reà ­a, nosotros/as reà ­amos, vosotros/as reà ­ais, ustedes/ellos/ellas reà ­an (I used to laugh, you used to laugh, he used to laugh, etc.) Future Indicative of Reà ­r yo reirà ©, tà º reirà ¡s, usted/à ©l/ella reirà ¡, nosotros/as reiremos, vosotros/as reirà ©is, ustedes/ellos/ellas reirà ¡n (I will laugh, you will laugh, he will laugh, etc.) Conditional of Reà ­r yo reirà ­a, tà º reirà ­as, usted/à ©l/ella reirà ­a, nosotros/as reirà ­amos, vosotros/as reirà ­ais, ustedes/ellos/ellas reirà ­an (I would laugh, you would laugh, she would laugh, etc.) Present Subjunctive of Reà ­r que yo rà ­a, que tà º rà ­as, que usted/à ©l/ella rà ­a, que nosotros/as riamos, que vosotros/as riais, que ustedes/ellos/ellas rà ­an (that I laugh, that you laugh, that she laugh, etc.) Imperfect Subjunctive of Reà ­r que yo riera (riese), que tà º rieras (rieses), que usted/à ©l/ella riera (riese), que nosotros/as rià ©ramos (rià ©semos), que vosotros/as rierais (rieseis), que ustedes/ellos/ellas rieran (riesen) (that I laughed, that you laughed, that he laughed, etc.) Imperative of Reà ­r rà ­e (tà º), no rà ­as (tà º), rà ­a (usted), riamos (nosotros/as), reà ­d (vosotros/as), no riais (vosotros/as), rà ­an (ustedes) (laugh, dont laugh, laugh, lets laugh, etc.) Compound Tenses of Reà ­r The perfect tenses are made by using the appropriate form of haber and the past participle, reà ­do. The progressive tenses use estar with the gerund, riendo. Attaching Pronouns to the Reflexive Form, Reà ­rse The reflexive form, reà ­rse, is usually used with little difference in meaning from the nonreflexive form. When the pronoun is attached to the verb—which occurs only with the infinitive, the gerund, and the imperative mood—a change in the accent for reason of pronunciation is needed only for the gerund (also called the present participle). Thus the correct form for the gerund of reà ­rse is rià ©ndose; note the accent on the e of the stem. Conjugated forms of the gerund are rià ©ndome, rià ©ndote, rià ©ndonos, and rià ©ndoos. The pronoun can simply be added for the imperative forms. Thus the reflexive form of rà ­e is rà ­ete. Sample Sentences Showing Conjugation Si rà ­es, yo reirà © contigo. (If you laugh, I will laugh with you. Present indicative, future.) En fin, rà ­e como nunca ha reà ­do en su vida. (Finally, he is smiling as he has never smiled in his life. Present indicative, present perfect.) Siempre nos hemos reà ­do con vosotros y nunca de vosotros. (We have always smiled with you and never at you. Present perfect.) No estamos rià ©ndonos de nadie. (We arent laughing at anybody. Present progressive.) Sonrio despuà ©s de unos segundos de incomodidad. (She laughed after a few seconds of discomfort. Preterite.) Quiero que riamos juntos. (I want us to laugh together.  Present subjunctive.) En las fotos tomadas ante del siglo XIX, las personas casi nunca sonreà ­an. (In photos taken before the 19th century, people are almost never smiling.  Imperfect.) Para hacer cebolla frita en conserva, yo la freirà ­a a fuego lento hasta que estuviera transparente. (To make fried onions for canning, I would fry them on a low flame until theyre transparent. (Past participle used as an adjective, conditional.)  ¡Sonrà ­e incluso si duele! (Smile even if it hurts! Imperative.)

Exploring the Pros and Cons of Bioplastics Essay - 644 Words

Plastics are one of the most versatile of all material and we use them in everyday items such as cars, pens, planes, toothbrushes and the list goes on. But there is a problem, plastics are synthetic and take very long to decompose in landfills so we can’t get rid of them easily. Well, now there is a lot of hype about bio plastics; plastics that are made using corn, potato or other annually renewable sources which are compostable biodegradable (Glen 2009). Bio-plastics are commonly portrayed as environmentally friendly in terms of the time it take to decompose but there are many more cons to bio-plastics than pros. The cons that outweigh the short decomposing time scale are methane emissions, recycling problems and food price inflation.†¦show more content†¦Furthermore, the bio-plastics create problems for recycling facilities, adding to the plastic problem. Some studies show that bioplastics will contaminate petro plastic recycling if the concentration is higher than 0.1% (1000 ppm) and the recycled material will be useless (About bioplastics 2010). Once the production and use of bioplastics increases, it will be very hard to actually control the concentration of bioplastics in recycling units as it looks the same as petro plastic to consumers (Bioplastics and biodegradable plastics 2010). Therefore, if bioplastics are used on a bigger scale than, it will undermine the current recycling efforts. The only solution to this will be to totally replace petro-plastics with bioplastics but, methane emissions are certainly a big risk. Another, risk is the inflation of food prices if bioplastics are used on a larger scale. As discussed earlier, bioplastics are made using corn starch, potatoes and pea startch and the bioplastics industry is growing every year. The more this industry grows the more demand it will create for these foods. It will be almost like we are farming to grow plastics. Some experts speculate that, by 2014, almost a quarter of US gra in production will be turned over to biofuels and bioplastics production, potentially causing a significant rise in food prices (Michael Good 2010). There is already not enough food to go around due to the rising

New Respiratory Poses Potential Threat to Humans Free Essays

There are a lot of new bacteria and viruses being discovered almost every day. Some of them are new strains of previous species while some are entirely new species that have yet to be studied and usually cause no harm to humans. However, when the Adenovirus, the causative agent of the common cold, which is not a lethal illness to most people, mutates into a new form and mysteriously kills a lot of people, this is a cause for alarm. We will write a custom essay sample on New Respiratory Poses Potential Threat to Humans or any similar topic only for you Order Now In this connection, according to an article written by Associated Press and was published in Quad City Times, a mutated form of the Adenovirus has killed 10 people across the United States in last 18 months. In addition, the new form, which is called Ad14, has caused 140 illnesses in states such as Washington, Texas, Oregon, and New York. The virus was first reported last year in New York City, where it killed a 12-day old girl. Based on the article, the Centers for Disease Control and Prevention (CDC) was puzzled by the new strain of the Adenovirus, which has only more than 50 variants. However, they emphasized that there was no need to be alarmed as the mutated virus does not pose a serious threat to humans. Moreover, the CDC is also working on a vaccine for the virus which they hope to release in 2009. What fascinated me most about the article is the fact that the Adenovirus, which usually causes mild forms of sicknesses, has mutated into a new and possibly, deadly form. Being a student taking up microbiology, I believe that this discovery of a mutated variant of a virus means that it is possible for other viruses, and even bacteria to mutate into a more lethal and more dangerous form. It is possible that the virus was exposed to certain factors which altered its nutritional requirements and as a result, made it evolve like in the case of certain bacteria such as E. coli. References. Quad City Times. (November 16, 2007).   New respiratory bug has killed 10 people. Retrieved December 2, 2007, from http://qctimes.com/articles/2007/11/16//news/local/doc473e0d1de7e4d991086475.txt How to cite New Respiratory Poses Potential Threat to Humans, Essay examples

Marketing Management Segmentation Reflects Effective

Question: Discuss about the Marketing Management for Segmentation Reflects Effective. Answer: Introduction: Segmentation reflects effective division of the entire population into several groups as per the specific characteristics (McDonald, 2012). Now, McDonalds is presently conducting business in the entire world market for achieving sustainable growth in the market. For that reason, McDonalds have included different types of segmentation strategy for penetrating the global market in an appropriate way. McDonalds have included geographical segmentation, as it will allow the organization to develop specific penetration plan for each region. Moreover, McDonalds have utilized demographical segmentation based on the gender, age and occupation for enhancing the loyalty level of the customers in an appropriate way. Furthermore, McDonalds also have focused on the behavioural segmentation perspective for including the factors like personality, social class, degree of loyalty and user status in an effective manner. In addition, McDonalds have included psychological segmentation strategy for utiliz ing the cultural and lifestyle characteristics of the customers in an appropriate way. Target market strategy of McDonalds: Targeting reflects selection of specific group from the segmented groups for enhancing the sales volume in a major way. Many studies have highlighted the fact that proper utilization of target market strategy is necessary for fulfilling the entire business objectives. For that reason, McDonalds target market strategy is primarily focused on the teenagers, kids or families for achieving their desired sales volume. McDonalds have targeted kids from the age group between 8-25 years for creating desired impact on the market (Crawford, 2015). On the other hand, McDonalds also have targeted entire families for developing strong brand in the market. References: Crawford, A. (2015). McDonald's: A Case Study in Glocalization. Journal of Global Business Issues, 9(1), 11. McDonald, M. (2012). Market Segmentation. John Wiley Sons, Ltd.

Does Social Media Influence Activism and Revolution on the World Stage

klha essays

klha essays Software Giant to Outline Case for Consumer The European Commission has recently sued Microsoft for a number of so called anti-trust violations. Microsoft has now delivered an argument against the accusations explaining and defending their actions, as well as sighting their problems with the fact that the Commission seems to be making law simply to restrict Microsofts privileges. Microsoft argues that these accusations and proposed restrictions are more to help rival companies than to restrain its assumed monopoly. One major argument is that Microsoft ties in its Media Player to the typical Windows operating system. The Commission contends that Microsoft is preventing consumers from choosing their own media player. Microsoft explains that people do not want Windows without the Windows Media Player and that there is no evidence that alleged tie has restricted consumer choice. Yet, the Commission maintains that if the Media Player becomes dominant, any company that intends to sell content in audio or video form will have to ma ke sure it is in WMP format. Microsoft will essentially be able to charge a toll for each transaction. The trial, which will take place in European Courts, could take anywhere from a few months to five or six years. Microsoft Corporation may not officially be a pure monopoly, but it certainly has many of the characteristics. For one, the Windows operating system has become a standardized product, preventing any competition from entering the market. Factors such as this one in a market are known as barriers to entry and are a clear sign of a monopoly. Also, Microsoft is a price maker, which means that they can somewhat control the price of a specific product, in this case an operating system (Windows, etc), by changing its market supply. Essentially the only way for Microsoft to increase their sales of Windows OS is to lower the price. This shows that marginal revenue ...

How have anthropologists responded to colonialism in different Essay

How have anthropologists responded to colonialism in different historical moments - Essay Example In regards to this, anthropologists have been intrigued to study response of certain areas to colonialism at different times in the history (Serena & Warms, 2010). Colonial era binds modern anthropology practices and origin. However, the eighteenth age of European enlightenment was the cause of the colonialism that characterized the nineteenth century. The anthropologists were intrigued to articulate passive subjects in an essentially manner because of the industrial revolution in the 19th century and its romantic retrenchment. Approaches to colonialism are either in view of ideology and symbols environment and economy, and biology. Moreover, science and rationalism were some of the impetus to the anthropologist’s movement. Anthropologists provided the basic information that was fundamental in governing of the colonial government possessions in the first half of the twentieth century. In regard to this point of view, the anthropologists’ demanded for financial support f or their projects from the colonial governments. Since colonialism was destined to occur with or without the support of the anthropologists, their emergence was therefore not meant to support the colonialists (Serena & Warms, 2010). ... Cultural changes are not static, therefore, the end decline in colonialism did not imply an end to, foreign influence, foreign intervention, or forced cultural change. Modernization advances to development have been contributed by anthropologists because they were drawn into it by their own desire to support and the needs of the government. This is attributed to the training of the development of development anthropologists as intermediaries between the recipients of aids and the organizations. Their contribution in colonialism is associated to their capability and comprehension to provide well-argued appraisal and analysis. The following case studies shows the contribution of anthropologists in the colonial era in West Africa on monetary transition and Aboriginals population in north Australia (Serena & Warms, 2010). French colonialists’ administration unsuccessful failed in their attempts to substitute West African Volta region, currently known as Burkina Faso, local monetar y form of cowry shells with its francs for about a half a century (Sahir, 2004). This was based on the stiff opposition that was staged by the local government. Cowries gained vitality despite the prohibition from the colonial governments because the emerging urban market in the Volta region had accepted them as a medium of exchange. Conflicts that were generated by the monetary policy and the colonial system gave birth to the practical difficulties that acted as an impetus to the local government to implement measures to boot the use of their local currency. Before the arrival of the French in the Volta region, commerce was characterized by traders commuting with their goods on their donkeys or heads from one

Ebay Research Paper Example | Topics and Well Written Essays - 2000 words

Ebay - Research Paper Example The sellers have the choice of accepting bids for their products. They can also use the Buy It Now option that provides the buyers with the opportunity to buy the product at a fixed price right away. Bidding in the online auction system starts at a price established by the seller and remains on the eBay for some days so that the buyers can place their bids. At the end of the listing, the buyer who has the maximum number of bids wins. On the other hand, when the Buy It Now option is used, the first buyer who is volunteering to pay the price established by the seller receives the item. The online auction website was established in the year 1995 as the AuctionWeb. Pierre Omidyar, an Iranian computer programmer born in France founded AuctionWeb on 3 September 1995 in San Jose, California (â€Å"The history of†). The first employee was recruited by eBay in the year 1996. eBay entered its first deal of third-party licensing in November 1996 with Electronic Travel Auction. It made use of the SmartMarket Technology to sell travel products and tickets of planes. In January 1997, over 2000000 auctions were hosted by eBay in comparison to 250000 that were hosted during the year 1996. In September 1997, the company’s name was officially changed from AuctionWeb to eBay after it received $6.7m from Benchmark Capital. â€Å"To save money, Omidyar linked the new Web site with an existing site he had created for his consulting and technology business, Echo Bay Technology Group. The Web address for that business was ebay.com† (Gitlin). The number of eBay†™s employees increased to 20 by March 1998 along with a population of half a million users. Its revenues in the US reached $4.7m (â€Å"The history of†). In 21 September 1998, eBay went floated over the stock exchange that resulted in the making of the founders of the company, billionaires. On the very first day of trading, the price of target shares of eBay increased from $18 to $53.50. eBay

Far Horizon's case study Essay Example | Topics and Well Written Essays - 2500 words

Far Horizon's case study - Essay Example Lastly, it should be aware of the income level of its target market, so that it can appropriately price the goods and services that it will offer, to match the market's willingness to purchase. Far Horizon has to make a product strategy that is very sensitive to its customers unique needs, as well as one that is innovative and quality-driven. The customers for this type of service are very scrutinizing, in a way that each set of customers have very unique needs, which might not be the same which the next set of customers. Far Horizon must therefore avoid the scenario where it will commoditize its products, in a way that it provides the same type of service to its different customers. Instead, the company must allow for a certain level of customization, for each accommodation package that the customers will demand, and it must make its service cater to the needs of its customers (and not the other way around). Another factor that will affect its product strategy is the generic type of service that this industry provides. Far Horizon can capitalize on this, by making its services more unique, to rouse more interest from its present customer base and to uniquely distinguish itself from competitors and similar companies. Along with customization, unique new features and creative add-ons will make Far Horizon, as a brand, stand-out from the rest of the competition. For example, the company may be bold enough to try hosting themed team-building events for corporate customers, or they may also try to hold festivals and cultural shows (in cooperation with the state) to coincide with a related conference or convention. Lastly, Far Horizon has to focus on consistently delivering quality-driven service to all of its customers. The high-level of customization and innovation will bring in a good bulk of the customers, but quality-driven service will retain the good customers, and will make them spread the news about Far Horizon's services to other potential customers. The innovative and customized features that the company can offer will be meaningless if quality is not stressed. Therefore, for Far Horizon to be a market leader in this service industry, it also has to be the market leader in delivering quality service to all of its customers. Place Strategy The most obvious factor that would affect Far Horizon's place strategy is its proximity to highways, airports or other transportation hubs. More and more customers would want to avail of Far Horizon's services, if the place was immediately accessible from public highways and airports. Another factor that can affect the company's place strategy is the scenic view that surrounds the place. While the company should focus on delivering customized and innovative quality service, it can also factor in the scenic surroundings around the place, to further enhance the company's image. Lastly, the overall attractiveness of the city or state of location affects the image that the company will project to its customers. If the city or state is known to maintain a high level of crime and theft, for example, then customers will still not be attracted to avail of Far Horizon's services. On the other hand, if the city or state has a good reputation among business and socio-civic organizations, then more customers will

Graphene Oxide (GO) as Antimicrobial Property

Graphene Oxide (GO) as Antimicrobial Property Over the past several years scientists have studied graphene materials (graphene, graphene oxide and reduced graphene oxide) for its antimicrobial properties and its future application in the biomedical field. To date, the exact mechanism for why graphene and its derivatives have antibacterial properties has not been fully understood due to experimental design variables. Scientists have agreed that oxidative stress, phospholipid extraction, and nanoknives all play an important role in the antibacterial properties of graphene materials. There are several techniques such as scanning electron microscopy, transmission electron spectroscopy, and mass spectroscopy that have been used to monitor change in morphology and cell death after exposure to graphene and its derivatives. Through these techniques scientist have been able to confirm that graphene materials are able to promote cellular death in both gram-positive and gram-negative bacteria, leading to its promising future also in pharma ceuticals. Graphene is a two-dimensional hexagonal structure, consisting of a basal plane (along the surface) and lateral edges, that are made up of sp2 hybridized carbons which form a conjugated à Ã¢â€š ¬ system. This à Ã¢â€š ¬-conjugated system makes graphene very hydrophobic and able to interact with the hydrophobic cell membranes of bacteria. Graphene oxide (GO) is most commonly prepared using the Hummers method, which consists of a multi-step synthesis. First the graphite material is oxidized to form graphite oxide and then this is exfoliated via sonication to form a single layer of material called GO. Through the oxidation process oxygenated functional groups are introduced into the basal surfaces and lateral edges of GO. On the basal surface of GO, the functional groups of epoxides and hydroxyl groups are present, whereas, the larger groups such as carboxyl and carbonyl groups form along the lateral edges. It is important to note that with the introduction of the oxygenat ed functional groups, the basal plane and lateral edges will need to adopt sp3 hybridized carbons, which results in the formation of defect regions where the à Ã¢â€š ¬-conjugated system is broken. The presence of these defects will be explored in more detail below as these areas are critical in the antibacterial properties of GO. In the literature, GO and other graphene materials have demonstrated through both physical and chemical mechanisms they have the ability to reduce bacterial cell count of both gram-negative and gram-positive bacteria1. Several pivotal studies have been conducted in order to determine the key mechanism behind the antibacterial properties of GO. Nada et.al studied the antibacterial mechanisms using Raman spectroscopy2, Zhang et.al studied the antibacterial activity using mass spectroscopy3, and Yusong et.al examined the effects of extraction of phospholipids from E-coli by graphene nanosheets4.These studies have led to the development of several mechanisms including the cutting of the membrane wall by the sharp edges of the defect sites (nanoknives), phospholipid extraction and oxidative stress. The various experiments to date regardless of experimental design demonstrated that it is not a single mechanism that is responsible for the antibacterial properties of GO but rather a combinat ion of several mechanisms that can contribute to the overall antibacterial properties. Ultimately, it is the breakdown in the cell membrane that causes intracellular leakage of vital proteins, nucleic acids, and cytoplasmic material that results in the loss of reproduction and cell death. The cutting mechanism also referred to in the literature as nanoknives is one of the most important mechanisms that lead to the antibacterial properties of GO. The sharp lateral edges of GO are able to penetrate into the cell membranes inner and outer layer. This leads to the loss of cell membrane integrity and leakage of intracellular materials such as the cytoplasm, nucleic acids, proteins and amino acids. Nada et al used a variety of techniques, such as Raman spectroscopy and scanning electron microscopy (SEM) to observe the cellular changes (deformation or loss of cell membrane integrity) of bacteria, such as E Coli when exposed to varying concentrations of GO material. Raman spectroscopy was used to determine how E.coli reacts to an increasing concentration of GO. From the research done by Nada and team the bands with the greatest change were those of adenine (a nucleic acid) (729cm-1), the S-S stretching vibrations (490cm-1) of the disulphide bonds (found on the surface of the cell) and the amide group (found in proteins) bending vibration at 610cm-1.2 The intensity of each of these bands increased with the increase in GO concentration. This positively confirms that GO had penetrated into the cell membrane, causing the loss integrity and allowing the intracellular material such as adenine and other proteins to leak from the cell. Once this material was leaked from the cell, its vib rational absorption increase the signal in the Raman spectrum intensified. The examined the effects of GO on E. coli using SEM was used to observe the morphological changes in cells after exposure to GO. Figure 1 below, shows the morphological effects on E. coli with increasing GO concentration2. Image A represents the control of E. coli cells. In image B, E. coli was treated with low concentration of GO causing morphological changes seen by the distortion (flattening or squishing) of the rod shape. As the concentration of the GO treatment increases the sharp edges of the GO material are able to penetrate into the cell membrane (as seen in the red arrow in image c) and lead to a loss of cell membrane integrity resulting in the leakage of the intracellular material. 2 This effect was not isolated to only gram-negative bacteria but also gram-positive bacteria as well, in which the thickness of the cell membrane is different however similar results were observed. Therefore, the thickne ss of the cell membrane does not play a critical role in the nano-knife cutting mechanism as GO was able to penetrate both the inner and outer cell membrane walls. The size of the GO also plays a key role in the cutting ability of GO due to the changes in the basal plane and lateral edges. A study lead by Perreault examined how altering the size of GO changed the cell viability of E. coli. GO sheets were altered by varying the sonication time and power in order to obtain GO sizes ranging from 0.65  µm2 down to 0.01  µm2.5 Using live/dead fluorescence staining it was determined that there was no change in cell viability (%living) when the bacteria was not in contact with GO as shown in the control of figure 2.5 The green dots represents the number of colony forming units (CFU) alive and the red dots are dead CFUs. The smaller sheet size of 0.01  µm2 has significantly lower cell viability (30%) when compared to the 0.65  µm2 sheet (73%).5 This phenomenon is explained by the fact that as the size of the GO material is decreased the amount of defects in the sp2 hybridized carbons of the basal plane and edges increases. T he defects are caused by either the addition of oxygen groups or shrinkage in size that destroys a portion of the basal plane. This effect creates additional sharp edges in both the lateral edges and basal plane leading to more nanoknives that are capable of cutting through the cell membrane. This allows for increase areas of interaction with the bacterial. This was also confirmed using SEM where larger sheet sizes (0.65 µm2) showed very little deformation and almost normal cell structure whereas smaller sheets (0.01  µm2) appeared to be flattened and deformed leading to a compromised cell structure5. It is interesting to note that the amount of surface defects also plays a critical role in the formation of reactive oxygen species (ROS) that will create oxidative stress to the cell membrane and additional loss of membrane integrity. Therefore, it is impossible to determine if only the physiochemical mechanism of cutting is the single mechanism that impacts cell viabili ty or multiple mechanisms do. In reality, with smaller GO size the loss of cell membrane integrity and intracellular leakage can be attributed to both the nano-knife effect and oxidative stress due to the increase in defects. This mechanism also has been shown to work in combination with other mechanisms such phospholipid extraction in which after cutting into the cell membrane the phospholipids are better able to be extracted by GO. This effect is due to hydrophobic attraction between the phospholipid tails and the à Ã¢â€š ¬-conjugated sp2 carbons of the basal plane. This will be discussed in further details in the later sections. GO is highly hydrophobic due to the à Ã¢â€š ¬-conjugation of the basal surface which allows it to interact with the phospholipid layer of the bacterial cell membrane. The oxygenated groups on GO provides a hydrophilic portion of the compound that is able to interact with the polar heads of the phospholipids. Yusong et al performed a detailed experiment on this and showed that extraction of the phospholipid molecules via hydrophobic interactions causes cell membrane deformation and collapse.5 There are two main mechanisms for the extraction of the phospholipids depending on the size of the GO material. With larger GO materials, the nanosheet will lie along the cell membrane causing a disruption of the phospholipid membrane; allow the GO material to embed itself into the lipophilic portions of the membrane1. For smaller GO materials, the sheet will lie perpendicular to the membrane and penetrate through the cell membrane (either partially or completely) via the nano-knife mechanism. This further supports the theory that it is not a single mechanism that allows for the antibacterial properties but a combination of several. The extraction of phospholipids occurs in several steps (see Figure 3). The first step involves a slight shifting of phospholipids due to the docking of the GO nanosheet as described by Yuesong (Image a).4 Next the phospholipid head will begin to break through the cell membrane and climb up the GO sheet (image b). This climbing effect is observed as result of the strong attractive forces between the hydrophobic regions of the basal plane and the hydrophobic tails of the phospholipids. This extraction process will continue until the GO material is covered completely with phospholipids with several layers of phospholipids climbing at the same time (image d). The phospholipids will evenly spread over the surface in such a way that the hydrophobic tails will align with the hydrophobic regions of the basal surface and the polar heads will align with the oxygenated functional groups of GO (images e and f).4 The loss of the phospholipids from the cell membrane causes a loss in membrane dens ity which weakens the cell membrane. Due to the loss of density and the penetration of the GO into the cell, cell membrane integrity is lost resulting in the leakage intracellular fluids. This effect can be seen with the aid of TEM as morphological changes are easily identified using this method of analysis (see figure 4)4. Image A represents the initial state in which no morphological changes have occurred when E-coli was treated with GO.4 Over time as the phospholipid extraction occurs, the cell membrane density will decrease as shown in images b and c seen by the Type B arrows. The last step in the process is when cell integrity is lost and the intracellular material begins to leak. This effect is also observed in the images d-f where the cells are transparent due to loss of the cytoplasm4. This confirms that the phospholipid extraction occurs with the aid of the nanoknives leading to loss in cell viability. Another group of scientist lead by Zhangs used mass spectroscopy to map the metabolites of E-coli before and after exposure to GO.3 A typical mass spectrum of E-coli without GO treatment is shown Figure 5a. The most important peaks are at m/z 306 which corresponds to glutathione (GHS), which is an antioxidant commonly found in E. coli, and the membrane phospholipids phosphatidylethanolamine (PE) and phosphatidylglycerol (PG), at approximately m/z 600-8003. As the concentration of GO increased the overall intensities of the GSH, PE and PG all decreased (see fig 5b). This aligns with the previous studies of Yusong in which the extraction of the phospholipids leads to a decrease in cell membrane density. This was clearly observed by the decrease in signal intensities of both PE and PG. In the mass spec results obtain by Zhangs team there was also a decrease in GSH intensity. GSH is a critical antioxidant found in E. coli and will act as a scavenger for any free oxygen radicals that may be present in the bacterias environment. GSH prevents the oxidative breakdown of the phospholipid membrane that can also lead to a loss of cell membrane integrity and intracellular leakage. This finding confirms the previous hypothesis that there are many mechanisms running in parallel that ultimately attribute to the overall antibacterial properties of GO. In this very example, the nano-knives are able to cut into the phospholipid membrane and start the chain reaction of phospholipid extraction. This extraction causes a decrease in phospholipid density which in parallel with the cutting of the membrane by the nanoknives and oxidative stress leads to a loss in cell membrane integrity. This loss in cell membrane integrity leads to a loss of intracellular material such cytoplasmic mate rial, nucleic acids and proteins.. As demonstrated by the mass spectrum results obtained by Zhang et al, oxidative stress occurs when there is a decrease in antioxidant concentration (such as GSH)3. The consumption of GSH occurs in the presence of reactive oxygen species (ROS) which are typically composed of hydrogen peroxide (H2O2), superoxide anions (O2*), hydroxyl radical (OH*) or singlet molecular oxygen species(1O2)1. When the antioxidants (such as GSH) are depleted the ROS compounds will then cause oxidation of key lipids in the cell membrane, proteins or even nucleic acids. The formation of the ROS compounds occurs due to the very nature of GO. When graphite is oxidized to form graphite oxide, the basal plane obtains additional defects as the result of the loss of à Ã¢â€š ¬-conjugation. This loss of à Ã¢â€š ¬-conjugation occurs due to the introduction of the oxygenated functional groups such as epoxides and hydroxyl groups which creates sp3 hybridized carbons. The introduction of the sp3 carbons alters the planer geometry of the basal plane by introducing tetrahedral carbons, creating defects in the lateral edges and basal plane. Additional defects can also be introduced as mentioned in the previous section when the size of the GO material is decreased. As the size of the sheets decreases the ability of the GO to stay as a perfect hexagonal structure also diminishes as the structure gets distorted to accommodate the smaller size. The process of oxidative stress begins with the formation of ROS compounds. Oxygen is absorbed to the surface of the basal plane or lateral edges at the defects sites to form surface oxides. These surface oxides release ROS species in the presence of antioxidants as a result of a redox reaction. In the presence of GSH (an antioxidant found in E. coli), the surface oxides found on GO are reduced by an electron transfer from GSH. Another GSH molecule will then donate a proton to the ROS species, causing its reduction and subsequent release of a water molecule.5 The deprotonated GSH molecule will then react with another GSH molecule to form glutathione disulphide. If GSH is not available, the ROS species will then oxidize the lipids in the cell membrane to form as a lipid peroxide radical causing oxidative stress to the cell membrane. This oxidative stress will continue down the cell membrane until the lipid peroxide radical encounters an antioxidant bound to the cell membrane such as V itamin E. It is important to keep in mind that with an increased amount of free oxygen radicals the extent of oxidative stress increases and the overall cell integrity decreases. As mentioned earlier, the size and shape of the GO plays a key role in determine the extent of the oxidative stress. As the size of the GO material decreases from 0.065 to 0.01 µm2 the amount of surface defects increases. Again this is due to the loss of the conjugation and destruction of the basal plane. With the smaller GO material the presence of additional defects allows for the formation of many more surface oxides that can later be reduced to form ROS compounds. These ROS compounds then will continue to deplete the antioxidants and lead to further lipid peroxidation. This effect will continue until enough oxidative stress exists to cause the membrane to collapse and bacterial death to occur. Perreault and team demonstrated this effect when they examined through Raman spectroscopy and cell viability testing that the size of the GO material plays a critical role in the ability of the material to induce oxidative stress. Figure 6 shows that as the size of the sheet decreases, the amount of disorder due to the defects (D band) increases. Therefore there is a direct correlation to number of defects and the ability of GO to form ROS species that interact with GSH. This is further confirmed with the graph in figure 6a which shows the %loss of GSH decreases with the increase in GO size. Therefore it not only the nanoknives that that are influenced by the size of GO but also oxidative stress due to the adsorbed oxygen and ROS formation. As demonstrated through the various studies conducted by Nada et al, Zhang et.al, and Yusong et al the key antibacterial mechanisms of GO are cutting via nanoknives, phospholipid extraction and oxidative stress that contribute to the overall antibacterial properties of GO. The research to date indicates it is not a single mechanism that creates the antibacterial properties of GO but a combination of all factors. How much antibacterial is dependent on the physical size of GO plays and the number of defects in the basal surface and lateral edges. As the size of GO decreases a larger degree of surface defects forms. These defects play two important roles in the antimicrobial properties of GO. First, an increase in surface defects creates an increase in the number of sharp edges that causes a loss of cellular membrane integrity. Directly, the cell membrane is compromised by the penetration of the nano-knives resulting in intracellular leakage of the cytoplasm, amino acids, proteins and n ucleic acids, Indirectly, once the nano-knives cut into the cell membrane it becomes embedded through attractive force between the hydrophobic tails of the cell membranes phospholipids and basal plane promotes phospholipid extraction. This extraction causes a decrease in cell membrane density which further breaks down the membrane causing additional intracellular leakage of key nucleic acids, cytoplasm and proteins. Lastly, the increase in surface defects of the basal plane increases the presence of reactive oxygen species. These species will react with any antioxidant present in the bacterial cell depleting their levels. Once depleted or reduced, the ROS will cause oxidation of the cell membrane lipids leading to a chain reaction of oxidative stress through the cell membrane. This also will lead to a loss of cell membrane integrity and intracellular leakage of key proteins and nucleic acids responsible for cell growth and replication. Without this material the bacteria cell will di e leading to the antibacterial properties observed in GO. With the development of drug resistant bacteria, new and inventive ways to treat bacterial infections need to be explored. GO with its unique chemical and physical properties show much promise as the next antibacterial treatment. Additional studies need to be conducted to determine the cytotoxicity of GO in animals and humans in order to development new treatment therapies. Zou,X.; Zhang, L.; Wang, Z., Luo, Y. Mechanisms of the Antimicrobial Activities of Graphene Materials. J. Am. Chem. Soc. 2016, 138, 2064-2077 Nada, S.S; Yi, D.K; Kim, K. Study of antibacterial mechanisms of graphene oxide using Raman spectroscopy. Sci. Rep. 2016, 6, 28443; doi: 10.103,srep28443 Zhang, N.; Hou, j.; Chen, S.; Xiong, C.; Liu, H.; Jin, Y.; Wang, J.; He, Q.; Zhao, R.; Nie, Z.. Rapidly probing antibacterial activity of Graphene oxide by Mass Spectrometry-based metabolite fingerprinting Sci. Rep. 2016, 6, 28045; doi: 10.1038,srep28085 Yusong, T.; Lv, M.; Xiu; Huynh, T.; Zhang, M.; Castelli, M.; Liu, Z.; Huang, Q.; Fan, C.; Fang, H.; Zhou, R. Destructive extraction of phospholipids from Escherichia coli membranes by graphene nanosheets. Nat. Nanotechnol. 2013, 8, 594-601, doi:10.1038/nnano.2013.125 Perreault, F.; Fonseca de Faria, A.; Nejati, S.; Elimelech, M. Antimicrobial Properties of Graphene Oxide Nanosheets: Why Size Matters. ACS Nano. 2015, 7, 7226-7236

The Revolutionary Visions of William Blake Essay -- church, society, lo

Between the late 18th century and early 19th century catholic religion was based off of the old testament in the Bible. During this time there was also a revolt against the aristocratic social and political norms of the Age of Enlightenment. While in this period, people began to rise against and question the way their lives were being ran by others, who supposedly had power which was derived from God himself. Yet at this time peoplesuch as William Blake found ways to spread the message of the unjust treatment the people would receive from hypocritical clergyman.As a youngman Blake only attened school long enough to learn to read and write, and left aroung the aage of ten. Blake grew up in the Moravian Church (protestant), and found religion to be an early/everlasting part of his life.Blake became a poet and artist, using his mediums lorg express his views on certain .Because of Blakes view that the Church of England was a major oppressor of the natural joys in which society can and should have, many viewed his work as too radical for the time period.Blake utilizes recurrent themes within his poetry; such as â€Å"The Garden of Love†,†Chimney Sweeper (Innocence)†,†Chimney Sweeper (Experience)†, and â€Å"London†, as a method of spreading his views of current religious establishments and their effects on the society which breeds them (at the time, and somewhat today). (Tolson 373,375) In the Garden of Love,a narrator goes on an adventure to a place where he once knew happiness. This place is now overran with religious figures, whom place restrictions on this place of joy.Till the point that the joy is taken away from this place, and the narrator. Blake uses this poem to show that the pursuit of happyness was being hindered by those wit... ...ossession. Going even further joy is an emotion, and to have it means to internalize the feeling of joy. By that logic Blake internalizes Jesus. Works Cited Altizer, T. J. J. (2009), THE REVOLUTIONARY VISION OF WILLIAM BLAKE. Journal of Religious Ethics, 37: 33–38. doi: 10.1111/j.1467-9795.2008.00374.x Cervo, Nathan A. "Blake's THE GARDEN OF LOVE." Explicator 59.3 (2001): 121. Academic Search Premier. Web. 2 May 2014. Lambert Jr., Stephen. "Blake's London." Explicator 53.3 (1995): 141. Academic Search Premier. Web. 2 May 2014. Roberts, J. and Rowland, C. (2010) William Blake, in The Blackwell Companion to the Bible in English Literature (eds R. Lemon, E. Mason, J. Roberts and C. Rowland), Wiley-Blackwell, Oxford, UK. doi: 10.1002/9781444324174.ch26 Tolson, Jay. "Blake: A Biography." The Wilson Quarterly 20.3 (1996): 96. Biography in Context. Web. 2 May 2014.