3,939 Views · 4 years ago
A paralyzed teenager will make the first kick at the 2014 World Cup before the opening match between Brazil v. Croatia. The exoskeleton, which is enabling the paralyzed teen to walk and kick a soccer ball, has been designed by Duke University supported by the Walk Again Project. This monumental step in technology will make for a very exciting first kick, and let's not forget that this teenager will be walking when prior knowledge told us that was impossible. What are your thoughts on the opening kick?
11,635 Views · 4 years ago
An appendectomy (sometimes called appendisectomy or appendicectomy (British English)) is the surgical removal of the vermiform appendix. This procedure is normally performed as an emergency procedure, when the patient is suffering from acute appendicitis. In the absence of surgical facilities, intravenous antibiotics are used to delay or prevent the onset of sepsis; it is now recognized that many cases will resolve when treated perioperatively. In some cases the appendicitis resolves completely; more often, an inflammatory mass forms around the appendix, causing transruptural flotation. This is a relative contraindication to surgery.
5,745 Views · 4 years ago
The purpose of an ELISA is to determine if a particular protein is present in a sample and if so, how much. There are two main variations on this method: you can determine how much antibody is in a sample, or you can determine how much protein is bound by an antibody. The distinction is whether you are trying to quantify an antibody or some other protein. In this example, we will use an ELISA to determine how much of a particular antibody is present in an individuals blood.
ELISAs are performed in 96-well plates which permits high throughput results. The bottom of each well is coated with a protein to which will bind the antibody you want to measure. Whole blood is allowed to clot and the cells are centrifuged out to obtain the clear serum with antibodies (called primary antibodies). The serum is incubated in a well, and each well contains a different serum (see figure below). A positive control serum and a negative control serum would be included among the 96 samples being tested.
11,383 Views · 4 years ago
Binding and Fusion: HIV begins its life cycle
when it binds to a CD4 receptor and one of two
co-receptors on the surface of a CD4+
Tlymphocyte. The virus then fuses with the host
cell. After fusion, the virus releases RNA, its
genetic material, into the host cell.
Reverse Transcription: An HIV enzyme
called reverse transcriptase converts the singlestranded HIV RNA to double-stranded HIV DNA.
Integration: The newly formed HIV DNA
enters the host cell's nucleus, where an HIV
enzyme called integrase "hides" the HIV DNA
within the host cell's own DNA. The integrated
HIV DNA is called provirus. The provirus may
remain inactive for several years, producing few or
no new copies of HIV
Transcription: When the host cell receives a
signal to become active, the provirus uses a host
enzyme called RNA polymerase to create copies of
the HIV genomic material, as well as shorter
strands of RNA called messenger RNA (mRNA).
The mRNA is used as a blueprint to make long
chains of HIV proteins.
Assembly: An HIV enzyme called protease cuts
the long chains of HIV proteins into smaller
individual proteins. As the smaller HIV proteins
come together with copies of HIV's RNA genetic
material, a new virus particle is assembled.
Budding: The newly assembled virus pushes out
("buds") from the host cell. During budding, the new
virus steals part of the cell's outer envelope. This
envelope, which acts as a covering, is studded with
protein/sugar combinations called HIV
glycoproteins. These HIV glycoproteins are
necessary for the virus to bind CD4 and coreceptors. The new copies of HIV can now move
on to infect other cells.
9,103 Views · 4 years ago
Human immunodeficiency virus infection / acquired immunodeficiency syndrome (HIV/AIDS) is a disease of the human immune system caused by the human immunodeficiency virus (HIV). During the initial infection a person may experience a brief period of influenza-like illness. This is typically followed by a prolonged period without symptoms. As the illness progresses it interferes more and more with the immune system, making people much more likely to get infections, including opportunistic infections, and tumors that do not usually affect people with working immune systems.
HIV is transmitted primarily via unprotected sexual intercourse (including anal and even oral sex), contaminated blood transfusions and hypodermic needles, and from mother to child during pregnancy, delivery, or breastfeeding. Some bodily fluids, such as saliva and tears, do not transmit HIV. Prevention of HIV infection, primarily through safe sex and needle-exchange programs, is a key strategy to control the spread of the disease. There is no cure or vaccine; however, antiretroviral treatment can slow the course of the disease and may lead to a near-normal life expectancy. While antiretroviral treatment reduces the risk of death and complications from the disease, these medications are expensive and may be associated with side effects.
Genetic research indicates that HIV originated in West-central Africa during the early twentieth century. AIDS was first recognized by the Centers for Disease Control and Prevention (CDC) in 1981 and its cause—HIV infection—was identified in the early part of the decade. Since its discovery, AIDS has caused nearly 30 million deaths (as of 2009). As of 2010, approximately 34 million people have contracted HIV globally. AIDS is considered a pandemic—a disease outbreak which is present over a large area and is actively spreading.
HIV/AIDS has had a great impact on society, both as an illness and as a source of discrimination. The disease also has significant economic impacts. There are many misconceptions about HIV/AIDS such as the belief that it can be transmitted by casual non-sexual contact. The disease has also become subject to many controversies involving religion.