Costimulatory activity of dendritic cells Essay Example | Topics and Well Written Essays - 750 words

Costimulatory activity of dendritic cells - Essay Example T cell activation is a highly regulated event involving complex receptor-ligand interactions, ultimately leading to downstream signaling events (Annu Rev Immunol. 2002). Optimal activation of naà ¯ve T cells requires at least two signals, antigen recognition and co-stimulation (Bretscher and Cohn 1970).The first signal requires engagement of an antigen receptor by foreign antigen. Professional antigen presenting cells (APCs) such as dentritic cells, macrophages and B-lymphocytes play a major role in this. They present different sets of antigens and serve to activate T cells at different points during immune response. These cells on encountering foreign antigens such as bacteria, engulf and destroy them. The major histocompatible cell (MHC) present in the APCs binds to a piece of this antigen and displays the antigen to the cell surface. This MHC molecule that displays the antigen is recognized by a compatible T cell receptor (TCR). Thus, these APCs communicate with a T cell (Underst anding Autoimmune Diseases. How Does the Immune System Work? 2007).For a T cell to respond to a foreign antigen on the MHC, a second signal is required. (P.Anton van der Merwe.2000).This second signal or co-stimulation is an antigen-independent signal required for sustained cell proliferation, effector/memory cell generation and prevention of energy or apoptosis. APC participation is required in the second signaling also. In addition to antigen presentation, these cells provide co stimulatory signals. ... Provide the co-stimulatory signal necessary for T cell activation. When a naive T cell binds to its specific peptide: MHC complex, the CD28 on the T cell's surface binds to the B7 molecules on the APC (Fig.1). These two signals together lead to the production of several cytokines. Fig.1: T cell activation by two-signal pathway. [Online] Available at http://www.clinsci.org. Dendritic cells are the most effective stimulators of T cell activation. They continuously express high levels of co stimulatory B7 (Fig 2). Upon recognition of infectious particles, these cells migrate through the lymphatics to the nearest lymph node. In the follicles of the lymph node, they come into close contact with the nave T cells where it begins expression of the B7 molecules. Once the T cells are activated, they will leave the lymph node and travel to the sites of inflammation. Macropohages, in the absence of infection, express low levels of MHC II and almost no co stimulators (B7). In the case of infection, however macrophages poses certain types of receptors that recognize differential carbohydrate patterns on foreign cells. They also have receptors for specific bacterial products such as lippolysaccharide endotoxin. When these molecules bind with their ligands, they stimulate the macrophages to up regulate MHC II and B& providing these cells with strong antigen presenting properties. They also start to secrete cytokines that aid in their functions. It is at this point that antigen presentation by MHC II will activate T cells. Macrophage Dendritic Cell B cell MHC-II Expression Low levels. Induced by Bacteria and/or Cytokines Always Expressed. Always Expressed. Inducible upon

History Essay Example | Topics and Well Written Essays - 250 words - 35

History - Essay Example It is for this notion alone that the memorial is more commonly known today as the Memorial to the Murdered Jews of Europe. The integration of the subterranean museum to the memorial is a good idea to give the whole structure a more relative association to the Holocaust. In a way this could serve as a cohesive rationalization that the visual abstract from the ideological meaning. This thought of commemoration is the entire reason behind all the controversies, praises and criticisms, behind Peter Eisenman’s work. The opinion of Prof. Norman Finkelstein is quite understandable from his perspective as and his viewpoint of the whole scenario as an industry. This is quite an entangled revisionist theory that sees all that happened under a very different life than all that is contained in most history books pertaining to World War II. Finkelstein opinion of a Holocaust Memorial in Washington DC is not without its merit. The whole endeavour seems futile as there is, in my view, no direct correlation that sufficiently necessitates it. This does, to a certain extent, instigates the exploitation of the Holo caust and the emotions it

Effective Training †Expectancy Theory Essay Example for Free

Effective Training – Expectancy Theory Essay Expectancy theory maintains that people will make an effort to achieve a standard of performance if they perceive that it will be rewarded by a desirable outcome (Wilson, 1999), giving more effort will result in better performance, these probable organizational rewards are valued by the employee, and better job performance will result to organizational rewards which includes an increase in benefits or salary. Desirable outcome is essentially a product of individual circumstances and perceptions and is therefore a subject to change. According to Wilson, at one time, lifelong employment and security of tenure at an equitable level of remuneration may have been the driving force for many employees. Those who have suffered the effect s of downsizing and redundancy are now likely to view the world in different manner, where jobs offering short term and reasonably remunerated employment prospects are more attractive than no job at all, and similarly, those in employment and those seeking employment are likely to have a positive view of work offering the prospect of development of differentiated and transferrable skills, as an investment in their future employability (Wilson, 1999). If one of the managers will say that he doesn’t have time for this theory stuff and he wants real-world training that will help him in his job, I will tell him first that, outsourcing, downsizing, delayering, and casualisation of jobs are all fashionable but these trends affect employees’ explicit or implicit relationships with their employer, and similarly, reduced career oppurtunities, shorter tenure, the need for transferrable skills to assist employability, and increased used of fixed term contracts weaken the traditional ties of loyalty to their company’s destiny psychologically as well as formally (Wilson, 1999). I will tell him that he should do anything which will encourage his employees to trust their organization or company because it is important to earn employees’ trust and loyalty to the company to achieve better productivity.

Geometry And Mathematics In The Renaissance

Geometry And Mathematics In The Renaissance Renaissance is one of the historical ages that truly had an impact on the modern civilization in terms of development in education, design and many other fields and also it did not ignore presenting out the most important figures during this age which had the same impact on modern civilization. This period of age started from the 14th century and ended on the 17th century starting in Florence in Italy and ending to the rest of Europe. Filippo Brunelleschi was one of its most important figures, shortly, the Renaissance style started to spread across Italian cities and some other countries like France, Germany, England, Russia and other parts of Europe at different dates and with varying degrees of impact. This paper will be discussing the impact of Renaissance on the development of mathematics and geometry in the modern age, its relation and the important figures that truly had an impact on this period. It will also discuss the important drawings and buildings that got affected by suc h innovations in this period of time. Renaissance is one of the periods that had an impact on mathematic and geometry due to the brilliant figures that have been in this period of time which will be discussed in this paragraph. First of all, Geometry is simply a branch of mathematics that is concerned with shapes, size, position of figure, and properties of a space like for example, a square have a property of the flat equal-distance lines from all sides that gives it, its shape and the same goes for the other shapes like rectangle, hexagon, circle etcà ¢Ã¢â€š ¬Ã‚ ¦Mathematics in general is the study of any types of structure, a space like a house, any designs etc., changes in velocity of an object, in general, anything that has to do with equations and calculations is categorized under mathematics. The most important figures that appeared in this period of age and had a true impact on Geometric and mathematics are Filippo Brunelleschi dating from 1377 1446 he is the inventor of the mathematics of perspective in painti ng. Paolo dal Pozzo Toscanelli dating from 1397-1482 creating a huge sundial and making astronomical calculations and also giving a higher accuracy in calculating latitude at the sea and luca pacioli who wrote a number of theories and developed the geometrical proportions. (Fletcher, 2000-11) Renaissance buildings heavily relied on the use of geometry and the mathematics in their design which heavily impacted other modern designs till now. Renaissance type of buildings relied on curves, arches, triangle, circles and squares, which are the main elements of geometry, also needs to be defines as buildings like churches, castles and much more relied on those basic elements and developed it into arches, domes, rectangular segments inside and outside the buildings as many floor plans could describe it. Renaissance building construction and how it was affected by such basic elements of geometry. The Renaissance great thinkers took the human being as a model for the universe being the perfect being made by god and used it in geometry and mathematics. This idea was developed by simply drawing this perfect figure which is the Vitruvian man standing in a square figure stretching his arms and legs forming a perfect circle around him. Based on these ideas, Leonardo made his own drawings based on the use of human proportions and the Vitruviuss theory. In the renaissance age, it was their aim to put such ideas developed into practice in real buildings .What was done is that he blended the use of circles and squares much in his general layout of his plan and in the plan itself he divided it further into spaces through the use of columns plus having the advantage of supporting the roof and as for the circular part, he used it to act as a domes which was one of the most important figures in th is period of time which gives the building its texture and unique style. In this drawing, Leonardo made some adjustments to the Vitruvius measurement of the human figure which was inspired by his own studies and observation. Finally after adjustments and his own studies, he created the perfect image of the human figure with the best proportions. Leonardo had the belief that god was the perfect geometer and the one who created the universe based on proportions and numbers, he believed that the human body was one of his perfect creation, based on Leonardos thought, he drawn the Vitruvian man stretching his own legs and arms to form a perfect revolving circle around him and a square. However, in order to make this work, he had to place the circle centered but the center on the square is a bit lower. Through adjustments and researches of his own measurements based on studies of life models, the Vitruvian figure is not recognized as an ideal image and proportion of the human body. Proportion is not only to be found in numbers and measures, but also in sounds, weights, intervals of time, and in every active force in existence. stated by Leonardo da Vinci (University of the Arts). The development of mathematics and calculations in the renaissance period is for sure one of the most important matters in this age. During the Renaissance, mathematicians and artists wrapped their arms around the questions of perspective, infinity, symbolic algebra and quartic equations, producing treatises on these subjects and offering fresh insights into the field of mathematics. The 15th through 17th centuries saw mathematical innovations in European countries like France and Italy, the impact of which extends to this day. These calculations were divided into different categories such as: Analysis vs. synthesis where the Renaissance saw the advancement of symbolic algebra. In his Artem Analyticem Isogoge of 1591, Franà §ois Vià ©te took the ideas of Ancient Greeks Euclid, Diophantus and Pappus and sought to explain and clarify them through systematic algebraic notation. In doing so he could explain the concepts of analysis and synthesis. Analysis, or an assumption of something that is looked for and the arriving at something admitted to be true through its consequences, was to be distinguished from synthesis, which is an assumption of something that is admitted (conceded) and the arriving at something admitted to be true through its consequences. Moreover, he applied rules for calculating species Vià ©te further established rules for species, as opposed to numerical calculations. His first rule stipulates to add a magnitude to a magnitude, or to add only homogeneous magnitudes, such as apples to apples; his third and fourth rules instruct to multiply and divide magnitudes, respectively, which will result in heterogeneous kinds. For example, a side multiplied by a side is a plane, not another side. Expressed through species, operators and units, equations could now be handled more easily. Also, in the development of equations, cubic and quartic was main ingredients Two breakthroughs during the Renaissance in mathematics involved the solving of both cubic and quartic equations, which had beguiled mathematicians before and during the Renaissance. Although the work was not his own, Girolamo Cardano is credited with giving general solutions to both types of equations in the form of radicals. Previously, equations of the second degree were solved in this manner, but not cubic or higher equations. He published these findings in his work, Artis Magnae, in 1545. Finally, the imaginary and complex numbers, another advance for mathematics during the Renaissance period was the acknowledgment of the validity of imaginary or complex numbers. Cardano, in solving cubic equations, came upon the appearance of negative numbers under the radical sign. Predecessors either brushed these aside or were not able to solve such numbers. Cardano, although he incorporated these numbers in his calculations, admitted that he did not fully understand them. Nonetheless, his work with these new numbers brought mathematics to a higher level of abstraction. After knowing the impact of mathematics and geometry in this period of time, renaissance did also impact modern age building design even though this period of age is so old but till nowadays it still impact us not in the design of the faà §ade but in certain designs. We can see how did the Renaissance influenced architecture and its design all around us. The Use of symmetry, columns, and balance of windows in modern architecture, whether at a bank or courthouse, or even in an expensive home, all point to the influences of Renaissance architecture on modern buildings. Hence to effectively study the influence of Renaissance architecture on more modern architecture one should begin by more closely examining the elements and impact of Renaissance architecture and how those elements have been incorporated into architecture today. Renaissance architecture followed the Gothic period of architecture, which gave us the cathedral at Notre Dame, and was succeeded by the Baroque period, which i s marked by highly ornate architectural designs and furnishings, and is often associated with the King Louis of France. The Renaissance period strongly emphasized the following elements: Geometry which relied on having buildings, windows, and doors in square and rectangular shapes. Proportion, balance was critical in the Renaissance, and elements of the structure needed to be designed in proportion to other elements of the building. Symmetry relied on the use of geometric figures came an emphasis on symmetry and clean lines. Regularity which means that there is a little about the Renaissance style that is random or impulsive. A building must have recurring themes and elements. To accomplish these design goals, the Renaissance style employs many recurring elements, including: Columns, Pilasters, Lintels, Arches and arcades, Domes, Symmetrical windows and doors and finally Niches with sculptures. Each of these elements is used in proportion and with much attention given to order and balance. Influence of the renaissance period came strongly in the 18th and early 19th centuries, which still many of these buildings still stand till today. Even later, in the 20th century, architects are reverting back to Renaissance designs when building grand homes much like the palaces found in Renaissance Italy and France. Various aspects of modern architecture find their roots in the Renaissance style. The features can include: Cube-shaped structure, Symmetrical faà §ade, Smooth stone walls, made from finely-cut stone or with smooth stucco, Low-pitched roof, Roof topped with balustrade, Wide eaves with large brackets, Horizontal stone banding between floors, Segmental pediments, Ornately-carved stone window trim varying in design at each story, Smaller square windows on top floor and Quoins (large stone blocks at the corners). (What Influence Has Renaissance Architecture had on More Modern Architecture, 2011) We could also see many of these elements every day, all around you. Nowadays, designers do seek to blend the use of columns and style that dated 600 years old to use it till now . Finally, to sum up, Renaissance time period showed a great improvement in the geometric and its use in the buildings as described in the paper and also the mathematical calculations used and how they were innovated and the name of the scientists who developed it. Moreover, we truly see the impact of geometry and proportions of space applied in their designs and how they made use of the basic elements such as circle, square, line etcà ¢Ã¢â€š ¬Ã‚ ¦which later on impacted the modern age designs

philisophical paper -- essays research papers

As Christians today we are faced with many ethical issues living in our society. Every time we turn on the TV to watch the news, pick up a newspaper and read the headlines, or read a magazine about world issues we can see situations happening in this world that challenge our morals and ethics. It is our duty as Christians to know what we believe and where we stand so we can back up our beliefs and try to interact with this world as morally correct as possible. There are some situations that we have no control over that appear ethically wrong to us and there is not much we can do if anything at all. At the same time there are things that we can do to try and reach people in some situations. It is our job to know the difference and stand up where we can but not force our own morals and ethical principles on everyone we come in contact with.   Ã‚  Ã‚  Ã‚  Ã‚  One issue that is very prevalent in the world today and all through out the history or the earth is the issue or war and combatancy. Now as Christians we know the bible says, â€Å"Thou shall not kill,† but is this issue really that simple? If we just took that stance and said that as Christians we shouldn’t go to war then our country and the world we live in would suffer. Let me get something straight right now before I go into this topic, I do not like war; I think it is an ugly thing, and I wish there would not be any more wars on this earth for the rest of its existence. But the fact of the matter is that there is war, there always was war and there will always be war until the second coming of Jesus Christ. War has become a way of life, it was not God’s original plan, but because of the entrance of sin into our universe, war was created. The first war we know of was a war in heaven between Satan and his angles and Jesus and His angels. Al l throughout the old testament we see the Israelites, God’s people, lead by God, going to war to obtain the land that God had promised to them. War is real and has become a necessity.   Ã‚  Ã‚  Ã‚  Ã‚  Just because war is here does not mean that it is an ok thing to do. War came about as a result of sin; with the beginning of sin there was the beginning of war. War has become a necessary means to get by in a sinful world. To protect the peace and the free way of living that we enjoy here in America, sometimes, we must go to war. As members of socie... ...o many people told them when they were growing up that they shouldn’t do it. You see, it’s not so much that they like it but they were just told not to do these things, so they did them. We have to inform people and let them make their own decisions; we cannot just force our opinions on them, and that never works. This is the same for all of our views as Christians. It does not just stop with health but it extends into our entire way of life. We must live our lives as examples for all to see.   Ã‚  Ã‚  Ã‚  Ã‚  As you see in all these issues we, as Christians, must take stands on what we believe is right, but we should not force our opinions and beliefs on others. This is what everything boils down to. God gave us the gift of choice, and this is something he gave everyone. As Christians we are called to try to lead people to God and his work not to force them. If they want to come to him that is a personal decision, all we can do is help them along, not push them. The best way to help someone is to show him or her by example. If we set good examples for other people in all the ways mentioned in this paper then we can begin to reach other people and help them to change.

Ancient Egyptian Culture :: Egypt Ancient World Culture

Somewhere around 1375 years before the birth of Christ, an Egyptian pharaoh publicly changed his name. That change signalled a return to long-standing tradition, a hallmark of Egyptian culture that flourished for more than three thousand years peacefully in the rich Nile River valley. The king had been called Tutankhaton. The last portion of his name, aton, was the name for the sun-god, which, in the years before the king's reign, had achieved preeminence among the competing deities in Egyptian religious tradition. The king changed his name to the one by which he is known today -- TUTANKHAMEN or, more popularly, King Tut -- and ended the brief experiment in monotheism in favor of the older religion with its promise of an afterlife. And what an afterlife the pharaoh would have! Embalmed in order to endure the elements of disintegration, richly attired to attest to his fabulous earthly wealth, magnificently housed to remind all on-lookers of the towering greatness of the entombed human -- the pharaoh lived on in perpetual association with the stone structures that rose portentously out of the hot, barren sands of the desert so close to the life-giving, greening Nile. And the solemn bearing of these great structures reminds people today of the human hope for immortality and the way an entire culture fashioned a collective immortality in astonishing stone. Here was a culture that would persist, just as its pharaohs would live on in their silent palaces. More interesting, perhaps, is the collective underwriting of the PYRAMIDS. No fewer than 70,000 workers would have been needed to lug limestone blocks from desert miles away to the building sites. Yet there is little evidence that the pharaohs had to coerce their subjects to leave their fields and families in order to build a monument whose completion any single worker would certainly never see.

Lady Macbeth’s Confession letter to Macbeth Essay

I am very sorry to say that I cannot live with the murder on my mind. Whenever I am asleep I dream about his death and I dream that my hands are full of blood. I am afraid of dark and I sleep walk reliving the night King Duncan was murdered. I cannot cope with the change in our life. I wish our life could go back to normal all the excitements all the joy, happiness and when you have beaten the Repel Scottish Lords. All the rewards you got for winning the battles. Since you have met the witches you have changed a lot you don’t even have time for your wife who you use to call the â€Å"my dearest partner in greatness†. Why did you have to meet them witches because I think they are the one who ruined our sweet life. We were living so peacefully and happy since them three â€Å"evil weird sisters† told you that you can be future king if you kill Duncan. You wrote to me and told me about the evil witches predictions. I know I am the one to blame for forcing you into murdering King Duncan. If he didn’t visit us and stayed with us this never have happened. I looked so easy and made me think that I have got the best chance to get him killed and make you the king because I wanted you to be happy. Since he died my life gone so bad and miserable I think it’s the guiltiness and I cannot live with it no more so I have decided that I am going to suicide.