The Adventures Of Huckleberry Finn Country Or Society Essays

The Adventures of Huckleberry Finn: Country or Society E.M. Forster makes a bold statement when he declares that he would rather betray his country than betray his friend. Forster takes a very moral stand on the issue and states that a friendship is often more important than a government's actions or society's beliefs. His opinion regarding the value of friendship is a common theme shared by many authors throughout history, including Mark Twain, and Alexandre Dumas. Mark Twain's classic novel, The Adventures of Huckleberry Finn, describes a young boy torn between what he feels his country and society expect of him and what his heart tells him is right. Society believes that slaves should be treated as property; Huck, who had befriended a runaway slave, sees Jim as a person, not property. In the end, Huck Finn decides that he would rather disobey society's teachings about slavery, than betray his friend by returning him to his previous condition of servitude. Further reiterating Forster's conception of the proper order of one's loyalty is a product of English folklore, Robin Hood. According to legend, Robin Hood robbed from the rich and gave to the poor in an effort to bring happiness to the peasants of Nottingham in an otherwise dreary time under the tyrannical rule of Prince John. A childhood friend of Robin, Maid Marion places her friendship with Robin Hood above loyalty to the crown. She has numerous opportunities to betray Robin Hood, but she does not. She sees the good he is doing for the land and the lone resistance he and his band of Merry Men provide against the evil Sheriff. Had she been loyal to her country, Robin Hood would have never been successful against the Sheriff of Nottingham and the citizens of her kingdom would have had to endure even greater injustices. Sharing many of the same principles Robin Hood embodies is Alexandre Dumas's The Three Musketeers. The famous trio of noblemen battle against the villainy of the Court of King Louis XIII. D'Artagnan, Athos, Porthos and Aramis fight to preserve the honor of their Queen, Anne of Austria, against the Cardinal Richelieu. Their famous motto " All for one and one for all!" illustrates the value they place on their friendship. Efforts to maintain their close ties of friendship help them in resisting an immoral government. Had they chosen to remain in adherence to the Cardinal's oppressive rule, they would have been unsuccessful in effecting change. The value of friendship has been a prevalent theme throughout both literature and history. Authors representing several eras have addressed the moral dilemma of friendship versus loyalty to one's country. Governmental leaders and their policies are transient; friendships last a lifetime.

Two Types of Diabetes

Two Types of Diabetes Free Online Research Papers Introduction Diabetes has almost become an epidemic in todays world. Diabetes is a disorder that affects the way your body uses food for energy. Whatever sugar we take is generally broken down into simple sugar called glucose in our body. This glucose circulates within the blood and enter into the cells with the help of insulin. Insulin is a hormone, made within the Beta-cells of Pancreas. Due to sedentary life style and genetic predisposition, the beta cells are not able to make enough insulin, which is a key for glucose to enter into the cells. The key is not there and the glucose keeps on circulating within the blood. This is called Diabetes. There are two main types. Type I Type II . There is another condition known as Pre-Diabetes. There are two main types of full-blown diabetes. People with Type 1 diabetes are completely unable to produce insulin. People with Type 2 diabetes can produce insulin, but their cells have become resistant to it. In either case, the glucose cant move into the cells and blood glucose levels can become high. When these levels remain high for long time, they can cause serious complications. Pre-Diabetes: Pre-diabetes is a condition in which the cells in your body are becoming resistant to insulin or your pancreas is not producing as much insulin as required. Your blood glucose levels are higher than normal, but not high enough to be called diabetes. This is also known as impaired fasting glucose or impaired glucose tolerance. Every individual who has a Diabetic father or mother must go for glucose tolerance test or GTT. This can help in diagnosing pre-diabetic condition. A diagnosis of pre-diabetes is a warning sign that diabetes will develop later. You can prevent the development of Type 2 diabetes by losing weight, making changes in your diet and exercising. Type 1 Diabetes In case of Type I (Insulin Dependent Diabetes) the person cant make any insulin. Type 1 most often occurs before age 30, but may strike at any age. This is typically caused by genetic disorder. The pancreas produces very little or no insulin anymore. Frequent insulin injections are needed for Type 1. However there are certain herbs like Salacia oblonga and Pterocarpus marsupium which are found to be useful even in Type I diabetes. Type 2 Diabetes People suffering from Type II diabetes are having enough insulin but the cells have become resistant to it. This type of Diabetes has become very common and is spreading like an epidemic everywhere around the world. The most important reason for the cells to become resistant to insulin is sedentary life style which is being followed by modern age people. 95 percent of all diabetes cases are Type 2. What can be the reason? Its a lifestyle disease, triggered by obesity, a lack of exercise, increased age and to some degree, genetic predisposition. So the only way to prevent diabetes is to change the life style, which is the basic theory of Ayurveda to fight any disease. According to Ayurveda, Stress and life style is the reason for most of the illnesses including Type II diabetes. Factors for developing Type II diabetes and herbs for them As we know that there is no problem with the insulin production. It is there in the body in enough quantity, but the only problem is that it is not able to open the cells to make the glucose enter into them. All the glucose keep circulating within the blood. The cells become resistant to insulin. The reasons for Insulin resistance are 1. Obesity The number one risk factor for Type 2 diabetes is obesity. Nearly 40 % of the patients suffering from Type II diabetes are obese. Excessive fat interferes with bodys ability to use insulin properly. According to Ayurveda this is called Stroto-avarodh i.e. blocked channels. This blockage in the channels of passage of Insulin is reason for greater insulin resistance. Food and life style which cause blockage in the channels or Stroto-avarodh are curd, banana, heavy greasy diet, overeating, excess daytime sleep. There are herbs which are useful in clearing the blockages and opening up the micro channels. These remove excessive fat from within the body. Herbs like Katuki (Picrorrhiza kurro), Vidang (Embelia ribes), Amalvetas (Garcinia cambogia), Triphala are useful in Type II diabetes because they open up the channels and helps in reducing the insulin resistance. 2. Sedentary Lifestyle According to Charaka- an ancient Ayurvedic healer, lifestyle is damaging to health and bears responsibility for the growing obesity and diabetes. Inactivity and being overweight go hand in hand towards a diagnosis of Type 2. Muscle cells have more insulin receptors than fat cells, so a person can decrease insulin resistance by exercising. Sushruta another ancient Ayurveda surgeon explains by giving an analogy that who suffers from diabetes should walk at least 100 kilometers a day to keep his sugar level under control. This indicates that one must walking and being more active also lowers blood sugar levels by helping insulin to be more effective. 3. Unhealthy Eating Habits 90% of people who have been diagnosed with Type 2 diabetes are overweight. Unhealthy eating contributes largely to obesity. Too much fat, not enough fiber, and too many simple carbohydrates all contribute to a diagnosis of diabetes. Eating right is can turn the diagnosis around and reverse or prevent Type 2. 4. Family History and Genetics It appears that people who have family members who have been diagnosed with Type 2 diabetes are at a greater risk for developing it themselves. Indians have a higher than normal rate of Type 2 diabetes. Having a genetic disposition towards Type 2 is not a guarantee of a diagnosis. Lifestyle plays an important part in determining who gets diabetes. So it can be prevented if we go for changed life style to avoid diabetes. 5. Increased Age Its a very sad but true fact. The older we get, the risk of Type 2 diabetes is increased. Even if an elderly person is thin, he/she still may be predisposed to getting diabetes. As we age, the pancreas ages right along with us. It doesnt make enough insulin it did when we were younger. Also, as our cells age, they become more resistant to insulin as well. 6. Stress, High Blood Pressure and High Cholesterol The hormones are under the control of our thought and our attitude towards events in life. The stress hormone immediately releases pool of glucose, corticosteroid hormones in our blood. There is immediate release of adrenal hormones, causing blood pressure and constriction of arteries. Not only do they damage your heart vessels but they are two key components in Metabolic syndrome, a cluster of symptoms including obesity, a high fat diet, and lack of exercise. Having metabolic syndrome increases your risk of heart disease, stroke, and diabetes. HERBS FOR DIABETES- Following are the herbs, which have been extensively researched by modern parameters by various research scholars. They have also been described in ancient Ayurvedic texts as herbal solution for diabetes. These are 1. Saptrangi Salacia oblonga 2. Vizaysaar Pterocarpus marsupium 3. Gurmaar Gymnema sylvestrae 4. Jamun Syzigium cumini 5. Bilva Leaves- Leaves of Aegle marmelos 6. Karela Momordica charanatia 7. Methi Trigonella foenum graecum 8. Neem Azadirachta indica 9. Tulsi Ocimum sanctum 10. Daruhaldi Berberis aristata 11. Haridra Curcuma longa 12. Sadabahar- Vinca rosea 13. Amla Emblica officinalis 1. Saptrangi Salacia oblonga This is a wonderful remedy for diabetes. It is a tree whose bark is effective in controlling diabetes. It is extensively studied in the western herbal schools, but in Ayurveda it is being used since ages. The herb have been found to have diabetes controlling properties. 2. Vizaysaar Pterocarpus marsupium This is a big tree whose bark is very useful for diabetes. The bark of the tree is made into a wooden glass and the glass is termed as The miracle cure for diabetes. Some water is kept in the wooden glass overnight and is consumed early morning by diabetes patients. The color of the water changes to brown and glass is changed after around 1 month when the water color does not change. Diabetes support contains extract of bark of this miracle tree. 3. Gurmaar- Gymnema sylvestrae- In Hindi language, Gur means Sugar and Maar mean Kill. Gurmaar means The sugar killer. It is a twine that is known since ages in Ayurveda for its sugar controlling properties. Recent studies show that it contains Gymnemic acid molecules responsible for its anti-diabetic action. They bind with glucose molecules in the intestines and inhibit their entry into the blood stream. Thus it is effective in controlling sugar levels. 4. Jamun Syzigium cumini- It is a popular fruit tree growing wild in plains of India. The seeds of this tree are dried up and then a powder is made of them. The powder of the seeds of Jamun fruit is very effective in controlling sugar levels. It is astringent in taste which is opposite to sweet. Anything astringent in taste is useful for diseases caused by excessive sweetness like obesity and diabetes. 5. Bilva Aegle marmelos- This tree has three leaves together on its branches. Any tree who has combination of three leaves is considered in Ayurveda as divine and seat of Lord Brahma, Vishnu and Mahesh. The leaves are offered every Mondays in Shiva temples. This fruit of this tree is useful in irritable bowel syndrome. The leaves of Bilva are excellent for diabetes. The leaves are dried and powder is made and mixed with other herbs for better results. 6. Karela Momordica charanatia- The juice of this fruit is a miracle in treating and preventing diabetes and its complications. 30 ml of Karela juice every morning empty stomach is recommended for best results. It can be taken along with Amla juice for better results, as Amla is rich in natural vitamin C and is also effective in diabetes. Karela contains natural chromium and other micronutrients, whereas Amla is also rich in natural anti-oxidants like vitamin C and others. 7. Methi- Trigonella-foenum-graecum- Since ages Fenugreek is being used as a medicine in India, Egypt, Middle east and other ancient civilizations. Fenugreek has excellent properties to bring sugar levels as well as cholesterol levels under control. The seed powder of Methi is used to lower down sugar levels. It can be mixed with herbs described above. 8. Neem Azadirachta indica- Azadirachtin, Nimbin and Nimbidin are effective alkaloids found in neem. They act not only as blood purifiers but also controls sugar level very effectively. Neem is also useful in many skin diseases like eczema, psoriasis, rashes. The skin diseases associated with diabetes also respond to this herb quickly. It also helps in clearing away the blocked channels and maintains the flow of bile from within the liver and improves liver function. 9.Tulsi Ocimum sanctum- It is popularly known as The Holy Basil is a sacred plant according to Hindu mythology. People in India worship this plant as it has tremendous medicinal properties. Regular use of leaves of this plant controls blood sugar levels very effectively. It is also useful in many types of cancers, viral and bacterial infections, sore throat, cough and cold etc. 10.Daruhaldi Berberis aristata- This is a rhizome growing mainly in South India. The roots of this herb are taken out and grinded well. The herb powder stimulates pancreas to pump more insulin into blood. It also helps in preventing insulin resistance among cells. It acts as a channel opener for glucose into the cells. This also purifies the blood. 11.Haridra- Curcuma longa- This is very popular herb and is commonly called Turmeric. Turmeric powder is an effective anti-allergic, anti-cancer, anti-inflammatory and one of the best natural anti-diabetic. It works in the same way as Berberis aristata. It helps in purifying the blood, channel opener, helps in reducing the insulin resistance and thus making the way for glucose into the cells. 12.Sadabahar- Vinca rosea- It is always flowering plant, growing almost in every house in India. It is known as periwinkle in English. The plant contains very precious alkaloids vincristine and vinblastine which are used in allopathic medicine as anti-cancer injections. The herb leaves are very useful in controlling the diabetes. The herb leaves are mixed with other herbs described above to get good results. 13. Amla Emblica officinalis Amla is worlds richest natural source of vitamin C and is natures super anti-oxidant. One amla contains 30 times more vitamin C than an orange. It prevents ageing and therefore delayes the onset of complications of diabetes. Amla powder, Amla juice can be consumed regularly to get the benefits in diabetes and other diseases. Research Papers on Two Types of DiabetesGenetic EngineeringPersonal Experience with Teen PregnancyThree Concepts of PsychodynamicBionic Assembly System: A New Concept of SelfEffects of Television Violence on ChildrenResearch Process Part OneAnalysis Of A Cosmetics AdvertisementLifes What IfsDefinition of Export QuotasThe Relationship Between Delinquency and Drug Use

Rotation Essay Example | Topics and Well Written Essays - 250 words

Rotation - Essay Example In this respect, we learned the important aspects as students when looking through the x-ray. We usually looked for small cavity or calculus, but we needed to look at the big picture because the lesion could happen around in the oral tissue might be missed. Essentially, this lesson will be useful in my next evaluation of an x-ray patient. Moreover, interpretation of the lesion is essential in accurate documentation that others can understand. In this case, we have to describe correctly the interpretation of trauma, pulpal lesions, and periapiacal lesions as viewed on a dental image. The main lesson here was not to interpret the kind of lesion because the doctor already has a license. Besides, we went to the second floor to have hands on experience on digital panoramic and cephalometric imaging systems. She explained the most significant part about the panoramic in the sense that it had no film involved. The technique was to have a good x-ray on the patient and therefore previous rest was necessary for it to be correct. The patients must bite on the notch of the bite-block then before placing their tongues against the roof of the mouth. In addition, light must be positioned at the mid sagittal plane and perpendicular to the mid nose and the second light angle position at the canine. I was able to take two x-rays on the patients and in the process, noticed that the rotation was a great improvement on my knowledge and clinical skills. In this regard, I look forward to the next

Sexism Essay Example | Topics and Well Written Essays - 1750 words

Sexism - Essay Example Gender would be considered as a social construction. The opportunities and treatment that face people would largely be presented in reference to such a person’s sex, hence a form of discrimination referred to as sexism. Benatar defines sexism as economic and cultural structures that create and propagate rigid. and elaborate sex-marking and sex-announcing patterns that cause division of the species based on sex into subordinates and dominators. Sexism would thus be considered as systemic where the system favours those with overall power. It is basically the wrongful discrimination of a person on the basis of such a person’s sex. The wrongfulness of this discrimination could be out of individual beliefs about a particular sex or because such a discrimination would unjustly harm the discriminated persons. The dominance of one sex in any society would imply that there is a sex that is being oppressed. Benatar (12) introduces first sexism in reference to cases where girls ha ve been victimised. These girls and women have been killed due to their female sex in places where there is strong preference for sons, referred to as female infanticide. Widows would also be forced to end their lives in the name of rituals such as the India’s sati. Neglect could also cause deaths of girls and women especially in times of short food supplies in communities where sons would be prioritised as girls would be left to die out of malnutrition. Many millions of girls have been deprived of education as the boys on the other hand would be provided with education. Even in places where girls would be allowed to access primary education, the ladder tilts to favour the boys in higher education. In Saudi Arabia, women have been prohibited from riding motorcycles or bicycles or driving vehicles. Sexism through language Language has perpetuated male dominance through trivialising, ignoring and sexualising women. The use of he in cases of unspecified sex and the generic term mankind in reference to humanity are some example in English that enhance sexism. Additionally, promiscuity would usually be applied to women only. Towards the end of the 20th Century, gender neutral language had been promoted and has been largely attributed to feminism rise. This language avoids gender specific titles and other usage considered to be sexist. Supporters argue that gender specific title and pronouns exhibits systemic bias that excludes people based on their gender. Their proponents however argue that promoting gender neutral language would lead to grammatical distortion of meaning. Other languages around the world, in contrast to the western Indo-European languages had gender specific pronouns arise recently in the early 20th Century. Turkish is one of the examples. Colonialism saw most cultures revolutionise in an attempt to be modernised or westernised through addition of gender specific pronouns. As a result, about a century ago, these gender neutral pronouns beca me gender specific. Sexism in mass communication media Mass media, including movies, newspapers, television and magazines widely reflect what the society assumes about gender. Movies, particularly pornography objectifies gender by depicting scenes where women would be coerced, humiliated, dominated or even sexually assaulted. It entails psychological, physical or economic coercion of the women folk to perform and model in such movies. But with the modern rise in feminism, magazines have largely been concerned with the achievements of women. Despite this, various magazines still define women in reference to men behind them. Eitzen and Baca-Zinn (268) document studies which have shown that

Voting behavior Essay Example | Topics and Well Written Essays - 1500 words

Voting behavior - Essay Example The choice of a certain candidate therefore seemed to reflect the people’s behavior, the state of the country and the specific concerns that the candidates had for the citizens. The paper will use various tables in order to describe the voting behavior among various people. Demographics affects how people vote because it has a direct reflection on what attitudes people hold to various issues, abortion being one of them. This has been supported by the election’s literature that suggests that thing like abortion and gayness receive attention when choosing a leader. Table six communicates largely on the voting behavior of voters to various candidates based on their attitudes towards abortion. From the table, it is clear that those people who supported abortion voted in large numbers for Obama as compared to McCain which was 78% and 20% respectively. On the other hand, the people who opposed abortion voted largely for McCain, 54% as compared to Obama who had 45%. Obama still received higher votes in those people who supported abortion for reasons such as rape and clear need but the difference was not much. The other candidates received minor votes ranging from 1-2%. This voting behavior has a clear suggestion on the candidate, their position on the variable and also the demographics of those people that voted. There is a clear suggestion from the table that Obama was also in support of abortion while McCain s against the whole issue of abortion. There is no way the people who supported abortion could support Obama or vice versa if he was not of the idea himself. In terms of demographics, there is a clear indication that those who supported Obama most in this variable are women as compared to men. This is because the issues of abortion are of concern to women because they directly affect them in reference to men. Another clear suggestion is that the population in support consists of younger people who are

Kinesin Moves by an Asymmetric Hand-Over-Hand Mechanism

Kinesin Moves by an Asymmetric Hand-Over-Hand Mechanism Introduction This review discusses the motion of kinesin, a double headed motor protein. A study was conducted to determine which of two motion patterns is the one which describes the movement of this protein: the inchworm model, or the hand-over-hand model. What is Kinesin? Kinesin is a protein in a class of motor proteins which are powered by the hydrolysis of ATP – the molecule responsible for transporting chemical energy for metabolism [1]. Kinesin transports large cargo about cells by walking along microtubules, hydrolysing one molecule of ATP per step [2]. It has been proposed than the force of the protein binding to the microtubule propels the cargo along [3]. Kinesin moves to the â€Å"plus† end of the microtubule, meaning it transports the cargo from the centre to the edge of the cell [4]. There is evidence that some kinesins have a role in mitosis (cell division), by separating microtubules or depolymerising them [5]. The Models The inchworm model describes motion with one â€Å"arm† of the protein moving forward, followed by the other, with the first arm always in the lead. There are two types of inchworm motion, symmetric and asymmetric, which are shown in the image below. The symmetric model takes smaller steps, so only one arm moves at a time. Asymmetric motion takes a single step, at the middle of which both arms move. In the hand-over-hand model, alternating arms move forward over each other. In the symmetric case, the molecule rotates in the same direction every time, but in the asymmetric case the molecule rotates in alternating directions. These models are shown in the image below. Main Results The papers main result shows that the kinesin protein moves using an asymmetric hand-over-hand mechanism. To reach this verdict, a variety of single molecule experiments were performed. They established that the individual kinesin dimers make discrete steps at random intervals along the microtubule, and may take as many as one hundred 8 nm steps before releasing. The movement is processive, meaning that the protein can make many consecutive steps without releasing the substrate (the molecule on which it acts – here, the microtubule). This motion exists even when external forces up to several pN are applied, which indicates part of the protein stays attached at all times. The active part of kinesin is composed of a dimer, with two identical heavy chains, each with a â€Å"head† attached to a common stalk. These chains join to a short â€Å"neck† composed of single polypeptide chains. The heavy chains are coiled round each other to allow the rotation necessary for the hand-over-hand model. This rotation is about the neck, but the motion of the heads turning would continue winding, summing until the heavy chains would join into a common stalk, preventing independent rotation. A study was conducted [6] showing that no significant rotation occurs of the stalk during the stepping motion. For a symmetric model, a large rotation (about 180 degrees) was expected in the hand-over-hand models. The basis for the definition of â€Å"symmetric† here was in three dimensions: the structure of the kinesin and microtubule must be identical at the start and end of each ATP hydrolytic cycle, except for the two heads having swapped places [6]. An example of this is simply the dimer rotating half a revolution about an axis perpendicular to the microtubule each step [7], hence the prediction for a rotation of 180 degrees. However this was ruled out, and an inchworm model was proposed. In this, only one of the heads is active in hydrolysis, but the possibility of an asymmetric hand-over-hand motion remained. This would mean that the head and neck move in such a way that the overall rotation of the stalk is suppressed, instead alternating between two distinct structures [8]. How They Were Obtained The step motion of individual native and recombinant (formed in the lab by combining genetic material from multiple sources) kinesin molecules was measured, using optical force-clamp apparatus. This technique uses light from a tightly focussed laser to trap small, polarisable particles in a potential well near the focal point [9]. It was found that the intrinsic stepping rates alternated between two different values for each step, meaning the molecules â€Å"limped†. The difference in steps implies there was an alternation in underlying molecular configurations, meaning the motion could not be fully symmetric (such as the inchworm and symmetric hand-over-hand motions should be). The discovery of the limp, along with other nano-mechanical properties, means the protein moves with an asymmetric hand-over-hand motion. Single molecules of kinesin were attached to microscopic beads, serving as markers for position and as handles for external forces. An optical trap was then used to capture the individual beads that diffused whilst carrying the kinesin, which were placed near the microtubules. This was while kinesin bound and moved. The motion was then tracked using nanometer level precision. A feedback-controlled force lamp was used to apply a constant backwards load during the motion, in order to reduce the Brownian fluctuations and improve the spatiotemporal resolution. It also allowed for the kinesin to move further, taking more steps, in order to show statistical significance. The Results A derivative of Drosophila melanogaster kinesin (DmK401) was shown to have an obvious limp, with large time differences in the steps despite the stochastic nature (and ensuing variability). Statistical analysis showed significant differences in the average step times for both slow and fast steps. The durations of the steps were then calculated as Ï„slow = 136  ± 6 ms and Ï„fast = 24  ± 1 ms. The limp factor, L, can then be calculated as the ratio of the mean duration of the slow stepping time to the mean duration of the fast stepping time. The distribution showed significant limping for the majority of molecules, but there was wide variation in the results. 63% of records showed L > 4, and the average was L = 6.45  ± 0.31. Some motors took many runs and had consistently higher limp factors than others, but the distribution was broad and the populations could not be separated of limping and non-limping molecules. Other kinesin molecules, such as the native squid kinesin, showed almost no evidence of limping – the same calculations were applied as to DmK401, and the times were calculated to be Ï„slow = 90  ± 4 ms and Ï„fast = 54  ± 2 ms. The difference is much smaller than that for DmK401. The limp distribution was also found to be narrower, with the average limp factor being L = 2.23  ± 0.14, only slightly higher than the estimated value for a non-limping molecule, L ~ 1.8. The test was then done with kinesin derivates of Drosophila which had increasing stalk lengths. Longer stalks mean the motors are less likely to limp. The largest stalk tested was that of DmK871, and this had a limp factor of L = 2.16  ± 0.17, which was indistinguishable from native squid kinesin. There was also a correlation between an increasing limp factor (therefore shorter stalks) and an increase in characteristic lifetime of the slow step time, whereas the fast step remained invariant. This suggests the limping comes from one head alone, and the other is indifferent. A bacterial expression of a derivative of human kinesin (HsK413) also limped, with limp factor = 2.98  ± 0.25, much greater than the native squid kinesin, but still less than DmK401 and DmK448. Rarely, squid kinesin molecules seemed to limp, making outliers – some of which limped consistently. Discussion As both native and bacterially expressed dimers from different species can limp, this behaviour may be a result of a common mechanism describing how all kinesin molecules move. The alternation between short and long step times during limping reflects an alternation between the intrinsic rate (the rate with which the population increases) and the time it takes to leave each phase where neither head is moving. This implies the structure of the kinesin-microtubule complex is different at the end of sequential steps. The mechanism describing the movement of kinesin must therefore be asymmetric, meaning the molecular configuration switches after each step. Symmetric mechanisms, by definition, cannot account for switching – inchworm models will not limp without additional (asymmetric) features, nor will symmetric hand-over-hand models. The detail of how kinesin motors move is not well known or understood, so we cannot look at how limping could relate to the structure of the motion, but there are some suggestions based on the asymmetric hand-over-hand mechanism. Limping could be caused by misalignment of the stalk coils, meaning the necks would be different lengths, hence the head with a shorter neck would need extra time to find the next binding site using a diffusional search and overall slowing the kinetics. Another option is that there could be over- or under-winding of the coils from hand-over-hand motion, causing torsional asymmetry. The energy required to coil or uncoil the stalk would be reduced, changing the equilibrium and the rate with which the head moves forward. Whilst there is no immediate explanation for the effect whereby the shorter stalks result in longer slow stepping times, it may be incorporated into later studies with further assumptions. However, these experiments have shown that more approaches are needed for single-molecule experiments to answer these questions. Despite the exact mechanism not being known, the experiments do show that the kinesin motors limp, and making the asymmetric hand-over-hand mechanism the most likely. Why is this Significant? This is a breakthrough in the field, as more detail can now be found on how biological motors move. By establishing how kinesin moves, other motors can be analysed to find their mechanisms for movement, and this helps to further our understanding of biology. The same experiment can be done with other proteins, or more experiments can be done with kinesin to better understand certain factors – for example, why the slow stepping times correlate to shorter stalks, or why limping appears to come from one head only. What Other Work has Been Done? Whilst many similar experiments have been conducted, this has improved the knowledge of kinesins movement by showing that the inchworm model does not apply. It has opened up avenues for either looking deeper into kinesins movement, or for finding the mechanisms for other motors. The experimental method used was also new, and was different from the previous study by Hua, Chung and Gelles [6], which was researching something similar. Hua, Chung and Gelles looked at the rotations in the movement of kinesin, with the null hypothesis of a symmetric hand-over-hand mechanism. This was done by immobilizing a derivative of Drosophila, and measuring the different orientations of the microtubules as it moved. Their findings were consistent with the inchworm model, which is why it was proposed initially. Conclusion The kinesin mechanism is now better understood than before, with more information gained in explaining the mechanism. This has presented more factors for consideration and created new questions to answer: the opportunity for further research is huge. Future experiments could consider different proteins movements, or look deeper into the kinesin mechanism. The discovery is significant as it has not only given more insight into biological motors, but revealed ample possibilities for more experiments in the field. Acknowledgement This review was written primarily based on the work of â€Å"Asbury, C L et al. 2003. Kinesin Moes by an Asymmetric Hand-Over-Hand Mechanism. Science. 302(2130).†, with all numerical values and the majority of content based on the paper, unless otherwise stated. References [1] Knowles, JR. 1980. Enzyme-catalyzed phosphoryl transfer reactions. Annual Revue of Biochemistry. 49, pp.877–919. [2] Schnitzer MJ. 1997. Kinesin hydrolyses one ATP per 8-nm step. Nature. 388(6640), pp.386–390. [3] Mather, WH and Fox RF. 2006. Kinesins biased stepping mechanism: amplification of neck linker zippering. Biophysical Journal. 91(7), pp.2416–26. [4] Ambrose, JC, et al. 2005. A minus-end-directed kinesin with plus-end tracking protein activity is involved in spindle morphogenesis. Molecular Biology of the Cell . 16(4) pp.1584–92. [5] Goshima, G and Vale, RD. 2005. Cell cycle-dependent dynamics and regulation of mitotic kinesins in Drosophila S2 cells. Molecular Biology of the Cell. 16(8) pp.3896–907. [6] Hua, W, Chung J, and Gelles, J. 2002. Science. 295, p.844. [7] Howard, J. 1996. Annual Revue of Physiology. 58, p.703. [8] Hoenger, A et al. 2000. Journal of Molecular Biology. 297, p.1087. [9] Greenleaf, W J et al 2005. Physical Revue Letters. 95, 208102.

Reading: An Essential Part of Life Essay -- Informative, Personal Exp

Reading is a pleasurable activity yet an essential part of life, as it is important for survival in the modern world. As Rohal Dahl quoted ‘ Books ... if you are going to be anything, they are vital in life’ (www.stlwritersguild.org 13/11/10). Children should be encouraged to read from a very young age, as the ability to read allows them to access information, develop into fluent speakers and allows them to be creative writers. A study carried out by Eckhoff (1983) on second graders demonstrates this as he examined writing of two different groups: one who read a highly simplified textbook whilst the other read a text containing many literature forms, results showed children who were exposed to various literary forms, seemed better able in using different literary forms in their writing compared to those who were presented with simplified texts (www.vtaide.com 4/11/10). Reading has played an important role in my life, especially through the early stages of my intellectual development. One of the first books presented to me were the hardback picture word books. These books had names of everyday objects together with its picture allowing me to recognise the items around the house. Rhymes such as: Old MacDonald, Twinkle Twinkle Little Star, Jack and Jill together with many others were also a part of this reading journey. My mum particularly liked reciting them to me, whilst I began to be engrossed in the lovely pictures of my nursery rhymes book. I also enjoyed the musical atmosphere they used to create, which as time went by allowed me to easily grasp the words, allowing me to recite the rhymes for myself. As Carl Sagan quoted ‘One of the greatest gifts adults can give to their offspring and to their society is to read to children’... ...y goes on Stephy and Callum begin to grow closer together and fall in love however the racial segregation between both of the races stands as a major problem together with the birth of their child Rose. As the story goes on Rose grew up and soon began to find out about her heritage which leads her in to more danger. Malorie Blackman is quite a creative writer, as she began to twist racial history. In this series she made the black more superior whilst making the whites inferior. In conclusion I begin to notice a drastic change in my reading pattern, as during my early years I began to read various fiction books however this pattern has changed and I now begin to engage in books which reflect the realities of life and the present world, in which we live in. I look forward into expanding this reading journey and enhancing my current knowledge through reading.