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

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

Haqqani Network - Research Paper Example The Haqqani Network operates under the supervision of Maulvi Jalaluddin Haqqani, a highly dangerous fighter and anti-soviet resistance commander, and his son Sirajudin Haqqani, who now handles the important affairs of this enemy network. This group has been existing in Pakistan since Soviet era and is spread across Kabul (Clarke, R, 2011, p.105). The Haqqani Network is claimed to have been in alliance with many intelligence groups such as Central Intelligence Agency (CIA), Osama Bin Laden and Saudi Arabia’s Spy Service (Takashi, 2012, para.2). The Haqqani Network runs under the leadership of Haqqani family. Jalaluddin Haqqani and his sons now lead this insurgent group. Acording to Mazzetti, Shane & Rubin (2011) the Haqqani family is the Sopranos of the Afghanistan war, a family that made out its earnings and rose from the bottom through exercise of all kinds of illegal activities like trafficking, kidnapping, extortion, and so forth (para. 1). That being said, they are also reported to acquire protection money from the American reconstruction funding that was particularly aimed at construction of schools and roads in Afghanistan. With increasing network horizon and an enormously vast web of connections, this group has many top-tier leaders that operate different parts of the group secretly. That being said, the pioneer of the group, Jalaluddin Haqqani is considered a chief figure in the leadership of this network. Jalaluddin acted as a mujahedin leader in his fight against Soviet forces where he received significant help from the ISI and CIA (Bowman, 2009, p.26). The leader himself focused more upon his hometown Zadran, which is a central territory that connects nine tribally linked districts at the border of Paktika, Khost and Paktia province. Since the leader Jalaluddin has turned old and weak due to illnesses, most of the network’s responsibilities and activities have been transferred upon

Government Branches Essay Example for Free

Government Branches Essay Which branch of government do you think is the most powerful and why? I believe the most powerful branch of government is the Legislative Branch, because of the power it processes to keep checks and balance on the other two branches of government. There are two different houses in the legislative branch, the first is the house if representatives and the senate. The House of Representatives consists of 435 members elected from all 50 states, the District of Columbia, and the United States territories. The states population determines the number of members elected from each state. There are 6 non-voting members that represent the District of Columbia, the Commonwealth of Puerto Rico, and four other territories of the United States. The senate consists of 100 members, two from each state. Members of the house are up for election or reelection every two year as opposed to the senate, which is every six years. Together they form the congress of the United States of America. Article 1 Section 8 lists the powers of congress. Some of the more important ones include the necessary and proper clause, the commerce clause, power to tax, power to spend, coin money, and ability to borrow money, these powers give congress the ability to make laws, buy and sell goods, control a federal budget and even borrow money from foreign countries. The necessary and proper clause is one of the most powerful in the Constitution. It allows congress to make all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this constitution. This has been used for all types of federal actions including the New Deal, McCulloch v. Maryland, integration in the states and in the federal kidnapping act. The power to tax and spend also gives congress an important power to control the federal budget, which includes Medicare, Medicate, Social Security, infrastructure, government, agencies, and maybe the most important, the Defen se budget. The House of Representatives is also given the power to impeach the President, Vice President, and all civil Officers of the United States. â€Å"Impeachment is a formal process in which an official is accused of unlawful activity and the outcome of which, depending on the country, can lead to the removal of that official from office or other punishment.† There is a two-step process in order to impeach an official. First â€Å"The House Judiciary Committee decides whether or not to proceed with impeachment. If they do, The Chairman of the Judiciary Committee will propose a Resolution calling for the Judiciary Committee to begin a formal inquiry into the issue of impeachment. Based on their inquiry, the Judiciary Committee will send another Resolution to the full House stating that impeachment is warranted and why (the Articles of Impeachment), or that impeachment is not called for. The Full House will debate and vote on each Article of Impeachment. Should any one of the Articles of Impeachment be approved by a simple majority vote, the President will be impeached. However, being impeached is sort of like being indicted of a crime. There still has to be a trial, which is where the US Senate comes in. The Senate will meet in private session to debate a verdict. The Senate, in open session, will vote on a verdict. A 2/3rds vote of the Senate will result in a conviction.† The Legislative Branch is more powerful than both the Executive Branch and the Judicial Branch because when it come down to the President voting on a piece of legislature or appointing a supreme court judge, congress has the last say. After a bill is passed by congress it is sent to the President for his vote. If the President veto’s the bill congress is able with 2/3 vote able to overturn the Presidents decision. Under Article 2, Section 2, of the US Constitution provides that â€Å"the President may nominate members of the Supreme Court, but that appointment only occurs with the advice and consent of the Senate. This means the Senate conducts an investigation of the candidates qualifications and personal background, determines whether he or she would adequately fulfill the role of Justice, then votes whether to approve or disapprove the nomination.† In the end each branch is supposed to provide checks and balances for one another, but without the approval or money tha t congress controls, the Executive Branch and Judicial Branch would have a hard time operating. Sources http://www.whitehouse.gov/our-government/legislative-branch http://www.law.umkc.edu/faculty/projects/ftrials/conlaw/congpowers.htm http://usgovinfo.about.com/od/thepresidentandcabinet/a/impeachment.htm http://people.howstuffworks.com/supreme-court-appointment.htm/printable

The Portrait Of Dorian Grey | Analysis

The Portrait Of Dorian Grey | Analysis Dorian is soon to recognize of his deviance from social norms and decides to indulge himself in everlasting pleasure. Eternal youth, infinite passion, pleasures subtle or secret, wild joys and wilder sins he was to have all these things (Wilde, page 106). Seeing as age will not have any toll on his appearance, Dorian is able to pamper himself with pleasures of the flesh perpetually. As Dorian Grays soul grows ugly, the world will never view him as ugly because his portrait will not allow it; hence the addition this creates to Dorian Grays Hedonism. Awareness/Soul It held the secret of his life, and told his story (Wilde, page 92). Dorian, now in addition to Basil, both claim that the portrait of Dorian Gray is a portal and reflection of both of their souls, and because of this they wish upon no one to have any sort of viewing access to the picture. The mistake Dorian makes with Sibyl is the first sign of the ugliness of his soul; the lad cannot bare to lay eyes on the portrait for it will judge him as a person and he just does not want to view that much of reality. The picture, changed or unchanged, would be to him the visible emblem of conscience (Wilde, page 92). Dorian allows his portrait to act as his conscience; in view of the fact that it tells him if his soul if good or bad, looking at this piece of art works as constant reminder of the should bring goodness and not evil. The decision of returning to his love Sibyl Vane would probably not be made without the paintings reminder of his wrongdoing. He was hasty to do the right thing and return to Sibyl the proposal of marriage regardless of the pain she has brought upon him; he had no tolerance for the thought of his soul decaying with ugliness. In Dorians attempt at goodness, he had failed; Sibyls death brought death upon possible marriage between the two, and if Dorian played on his wisdom, he would realize the portrait realized this before he did. Despite the tragedy of this death, Dorian took this as a blessed opportunity to explore and unleash his youth and beauty that he has been privileged to. The lad grasps the fact that he can please his wants and remain beautiful regardless; the corruption of his soul has a direct correlation to the ignorance of his conscience. Dorians realization of the fact that old age will affect everyone except him, as well as the reality that the suffering of his soul will not be apparent in his outer appearance rewards him with a sense of blissful delight. Beauty There is a direct correlation of character and beauty when the two are intertwined to show the changes in the picture; The quivering, ardent sunlight showed him the lines of cruelty round the mouth as clearly as if he had been looking into a mirror after he had done some dreadful thing (Wilde, page 91), we see that cruelty and diminishing beauty have been a result of Dorians careless actions. Dorians character and actions are shown in the face of the portrait, hence Wildes reference to the portrait as a mirror. This portrait would be to him the most magical of mirrors. As it had revealed to him his own body, so it would reveal to him his own soul (Wilde, pg. 107). The driving force behind Dorians want to be good is merely the conserve of his beauty. A feeling of pain crept over him as he thought of the desecration that was in store for the fair face on the canvas (Wilde, page 106). Dorian Gray is very cautious with his choice of words; he never stated that he did not want his soul to corrupt, rather be is more concerned with his looks so he states he does not want to be hideous. The biggest fright imposed on this character is that he is terrified that people will soon see his evil. Applicable Connections Taking an inside look at Freuds psychoanalytic theories containing the id, ego and superego, allow us as the reader to better understand and interpret the protagonists three elements of the psyche. Superego (Conscience) According to Freud, the superego is guided by the sense of right and wrong; failure to accordingly directly results in a feeling of remorse or guilt. The superego acts like a communication device to the conscious part of ones mind, sharing its intentions with the ego. Dorian Grays conscience served as a reminder that from a moral standpoint, his living was bad. Wilde creates an emphasis on bad living and how it correlates negatively with the physical appearance of ones face. It is apparent that Dorian shows constant disregard to the indicators of his conscience. By choosing to ignore them, Dorian Gray flips Freuds concept of the superego by a full 180 degrees. Mr. Grays conscience is indeed present and well, but its customary impulses in relation to the conscious mind have been transmitted to the portrait that Bail painted. This is exactly what permits Dorian to plunge into his corrupt immorality. Id (Unconscious) Although the id acts behinds the scenes of the conscious mind, the influence it carries is just as great. This is the part of the human psyche that stores ones desires and acts on the pleasure seeking principle. The sense of his own beauty came to him like a revelation. He had never felt it before (Wilde, page 27). Dorian Gray recognizes his beauty but it was only through the compliments and flattery of Basil Hallward that he was able to do so. His narcissism led him to the master-puppet relationship with Lord Henry. This hunt for pleasure would never have existed without Lord Henry who is the controlled of Dorian Grays strings. The portrait of Dorian Gray itself takes on all the sins of the protagonist, leaving no reason for him to regard his conscience and therefore resulting in no need for the repression of the unconscious. The pleasure seeking urge is left freely for Dorian to spoil his hedonistic self with. Ego (Consciousness) The ego loves to be in the spotlight of both the superego and the id seeing as the two are constantly fighting which intuition should be followed by the ego. The ego is also considered to be an innate knowledge of the state of ones soul. It is evident that Dorians conscious plays a larger than normal role on his mind. It is because of Basils portrait of Dorian that the young lad is able to act upon each and every single notion that travels through his mind. What the worm was to the corpse his sins would be to the painted image on the canvas. They mar its beauty, and eat away its grace. They would defile it, and make it shameful (138). The existence of this portrait calls for no need of a filter when gazing at his soul and eavesdropping on his unconscious. There is no longer a duty of ignorance by Dorians consciousness in terms of his hedonistic id. The only communication Dorians conscience has with his soul is through the painting therefore this does not phase him. The combat between the superego and id over the ego is not presence when it comes to Dorian. Not only is Dorian mindful of the shady and dusty corners of his soul, as well as all parts of his psyche, he seems to also find ecstasy in it all. The need of the consciousness to communicate with the conscience is no longer essential since his painting does so for him; all that is left for him to do is absorb it as another perk of his life. Due to the fact that the relation between the conscience, the unconscious, and the consciousness is lead astray, Dorian is given all the more reason to treat his soul in the same way as Lord Henry regards him, a manipulative study.

Black Death In 14th Century Europe History Essay

Black Death In 14th Century Europe History Essay The plague that we know today as the Black Death was actually a combination of two plagues. The Bubonic plague, the most common and significant of the two, was transmitted to humans by black rats infested with fleas. These fleas carried in them the lethal bacterium Yersinia pestis. The other less common, yet more deadly plague was the Pneumatic plague. This plague occurred when the bacterium spread to the lungs, resulting in severe coughing and easier communication to other humans. The ease with which these plagues were spread led to the infection of a considerably large number of Europeans. The Black Death was a time of great sorrow for most Europeans of the 14th century. During the 14th century, most people did not know where the plague came from. Most saw the plague as a punishment from God for mankinds sins. Today, we know that the plague came from East Asia. The plague came from the trade routes to Europe from some mysterious fountainhead of disease in the East.  [1]  This fountainhead was actually the Mongols. The flea-infected rats carrying the deadly bacterium accompanied the Mongols into central and northwestern China and Central Asia.  [2]  Traders from these regions took the rats with them to the island of Caffa in 1346; the disease quickly spread to Sicily and Italy. The Black Death pushed into southern France and Spain the following year. In 1348, the plague moved over the rest of France and into Germany. By 1349, the plague had moved into England, Scandinavia and northern Europe. In 1351, most of Europe was suffering from the effects of the plague. One of the most significant effects that the Black Death had on Europe was its lethality. From 1347 to 1351, the European population declined by 25 to 50 percent  [3]  The population of Europe at this time is estimated to have been about 75 million people; that is roughly 19 to 38 million people. The cities, whether they were large or small, were especially hit hard by the plague, with a mortality rate near 50 percent. Giovanni Boccaccio later described the plague as it swept over his city (Florence, Italy): No physicians council, no virtue of medicine whatsoever seemed to have an effect or profit against this sickness it spread no less rapidly than fire will spread to dry or oily things that lie close at hand.  [4]  Even the small farming villages suffered a mortality rate of 20 to 30 percent. Sheep and cattle want wandering over fields and through crops, and there was no one to go and drive or gather them.  [5]  The loss of life was so extreme in some areas that they r everted to waste land.  [6]   The Black Death sparked an economic dislocation that swept across Europe. This economical dislocation affected both the nobles and the peasants of Europe. As a result of the declining population, the number of laborers, or peasants, decreased drastically. This labor shortage caused a notable rise in the cost of labor. Although this was beneficial to the peasants, the labor shortage effectively lowered the standards of living for many aristocrats. The income of the landlords went down as their tenants decreased in number; their overhead kept going up.  [7]  The landlords did not like this, of course, and put forth efforts to lower peasants status back down while trying to increase their own status. In 1351, the English Parliament passed the Statute of Laborers, which attempted to limit wages to preplague levels and forbid the mobility of peasants as well. Although such laws proved largely unworkable, they did keep waged from rising as high as they might have in a free market.  [ 8]  This, along with new taxes, further strained the relationship between the aristocracy and the peasants. The aristocrats declining status paired with the peasants increasing status led to a social upheaval. As peasants became wealthier and gained more social status, they began to question the superiority of the nobles. This inevitably led to revolts. In the revolt known as the Jacquerie, French peasants rose up against the nobility because the nobility of France, knights and squires, were disgracing and betraying the realm.  [9]  They argued that it would be a good thing if they were all destroyed.  [10]  Landlords in England spurred a revolt by the issuance of a poll tax on adult peasants. The peasants refused to pay the poll tax and staged an uprising against the aristocracy. The revolt was initially successful as the rebels burned down the manor houses of aristocrats, lawyers, and government officials and murdered several important officials, including the archbishop of Canterbury.  [11]   The Black Death had a few lasting effects on Western Europe. One of the most important effects it had on Western Europe was its devastation of the European population. The European population thus did not begin to recover until around 1500 and took several generations after that to reattain thirteenth-century levels.  [12]  The social upheaval caused by the Black Death also shaped the future of Western Europe.Nevertheless, the rural and urban revolts of the fourteenth century ushered in an age of social conflict that characterized much of later European history.  [13]  The Black Death effectively altered the course of history for Western Europe and quite possibly the whole world.

Blindness and Sight in Oedipus the King - Lack of Vision :: Oedipus the King Oedipus Rex

Blindness in Oedipus the King People can be â€Å"blinded† to the truth. The answer to their question or solution to their problem may have been obvious. Yet, they could not "see" the answer. They were blinded to the truth. Associations have been made between being blind and enlightened. A blind person is said to have powers to see invisible things. They "see" into the future. The blind may not have physical sight, but they have another kind of vision. In Sophocles' King Oedipus, Teiresias, the blind prophet, presents the truth to King Oedipus and Jocasta. Oedipus has been blinded to the truth his whole life. When he does find the truth, he loses his physical vision. Because of the truth, Oedipus blinds himself. Jocasta was blind to the true identity of Oedipus. Even when she found out the truth, she refused to accept it. In this case, those who are blind ultimately do have a higher vision - the truth. Kind Oedipus started life with a prophecy that he would kill his father and marry his mother. In an attempt to avoid this fate, his parents, Laius and Jocasta, sent him into the mountains to die. However, a shepherd saved Oedipus. This shepherd gave Oedipus to Polybus and Merope. When Oedipus learned of his prophecy, he fled his home, thinking these people were his real parents. On his flight, he met Laius. He ended up killing Laius. He continued on, answered a riddle of the evil Sphinx, and ended up king of Thebes. With this kingdom, Oedipus married Jocasta. He had lived out the prophecy without even knowing he had. Thebes fell onto bad times, and a prophet put the blame on a polluter of the lands. Oedipus called on Teiresias, and Teiresias informed him that the polluter was the King. As Oedipus searched further and further, he discovered that he was the polluter and that the prophecy had come true. When Oedipus finally discovered the truth, he was so distressed that he ran pins int o his eyes, blinding himself. He had been blinded to the truth for so long. Oedipus was blind in more then one way. He was blind to the truth about his own life. Oedipus had no idea that his real parents were Laius and Jocasta. He was so blind that he got mad at anyone who was foolish enough to suggest such an idea. Blindness and Sight in Oedipus the King - Lack of Vision :: Oedipus the King Oedipus Rex Blindness in Oedipus the King People can be â€Å"blinded† to the truth. The answer to their question or solution to their problem may have been obvious. Yet, they could not "see" the answer. They were blinded to the truth. Associations have been made between being blind and enlightened. A blind person is said to have powers to see invisible things. They "see" into the future. The blind may not have physical sight, but they have another kind of vision. In Sophocles' King Oedipus, Teiresias, the blind prophet, presents the truth to King Oedipus and Jocasta. Oedipus has been blinded to the truth his whole life. When he does find the truth, he loses his physical vision. Because of the truth, Oedipus blinds himself. Jocasta was blind to the true identity of Oedipus. Even when she found out the truth, she refused to accept it. In this case, those who are blind ultimately do have a higher vision - the truth. Kind Oedipus started life with a prophecy that he would kill his father and marry his mother. In an attempt to avoid this fate, his parents, Laius and Jocasta, sent him into the mountains to die. However, a shepherd saved Oedipus. This shepherd gave Oedipus to Polybus and Merope. When Oedipus learned of his prophecy, he fled his home, thinking these people were his real parents. On his flight, he met Laius. He ended up killing Laius. He continued on, answered a riddle of the evil Sphinx, and ended up king of Thebes. With this kingdom, Oedipus married Jocasta. He had lived out the prophecy without even knowing he had. Thebes fell onto bad times, and a prophet put the blame on a polluter of the lands. Oedipus called on Teiresias, and Teiresias informed him that the polluter was the King. As Oedipus searched further and further, he discovered that he was the polluter and that the prophecy had come true. When Oedipus finally discovered the truth, he was so distressed that he ran pins int o his eyes, blinding himself. He had been blinded to the truth for so long. Oedipus was blind in more then one way. He was blind to the truth about his own life. Oedipus had no idea that his real parents were Laius and Jocasta. He was so blind that he got mad at anyone who was foolish enough to suggest such an idea.

Evaluation of Police Officer Candidates Essay -- Selection of Law Enf

Workforce selection practices have become more prominent over the years, particularly with law enforcement recruitments. This enhanced use of process selection allows for more advanced methods of assessing police officers. One reason for this extreme emphasis on selection systems is the elimination of unqualified police recruit applicants, thus ensuring that monetary resources are not wasted on the ill-equipped (Cochrane., Tett., & Vandecreek, 2003). Several factors impact the potential success or failure of police recruits, including tertiary studies; efficient communication skills; previous moral and ethical behaviour and psychological adequacy of recruits. However, just two of the four selection criteria including tertiary studies, and personality suitability will be analysed and evaluated in this literary review. Higher educated police officers are better equipped to serve in today’s complex and challenging environment through greater awareness of social and cultural / ethnic community issues; promoting a more professional image of law enforcement, as well as exemplifying themselves as ‘problem solvers’ rather than ‘reactive agents’(Trfymowych, 2007, pg. 419). Likewise, psychological and personality suitability of employees allows for police officers to screen out psychopathology as well as Identify individuals who match some ‘ideal’ profile of high performing police. Therefore, this review aims to determine whether or not the selected criteria reviewed are valid for use in a police recruit selection process through a detailed evaluation of each criteria. As the role of a police officer is becoming more complex in the 21st century with the advances in social and technological developments, the need for tertiary studi... ...). Psychological testing and the selection of police officers. Criminal Justice and Behaviour, 30 (5), 511-537. Dempsey, J., & Forst, L. (2009). An Introduction to Policing. Cengage Learning, Canada. Metchik,E. (1999). Police Quarterly. An analysis of the â€Å"Screening Out â€Å" Model of Police Officer Selection, 2 (1), 79-95. Smith, M., & Segal, J. (2008). Healing Emotional and Psychological Trauma. In HelpGuide. Web 23 Apr. 2015. http://www.helpguide.org/mental/emotional_psychological_trauma.htm Trofymowych, D. (2007). Police Education Past and Present: Perceptions of Australian Police Managers and Academics. Flinders Journal of Law Reform, 8 (10), 419-433. Vrana, S., & Lauterbach, L. (1994). Prevalence of Traumatic Events and Post-Traumtic Psychological Symptoms in a Nonclinical Sample of College Students. Journal of Traumatic Stress, 7 (2), 289-302.