Understanding lab tests Essay Example | Topics and Well Written Essays - 1500 words

Understanding lab tests - Essay Example Every Year nearly 1.5 million individuals in the U.S. suffer a heart attack (Acute Myocardial Infarction) and of these approximately 500,000 die. Ischemic Heart Disease is the principal cause of death in the U.S."This can be achieved by adding cardiac biomarkers in the artillery. ECG is the primary diagnostic tool which is nearly 100% specific but sensitivity is only63-82%. Gold standard of investigation for detecting Acute Myocardial Infarction is CK-MB; Cardiac specific Troponin can be added to this for better results. Coronary artery disease to a major degree is due to atheroma and its complications mainly thrombosis. Elevated LDL cholesterol is the single contributor of atherosclerosis LDLc, gets deposited in subendothilial layer of intima of the artery. This deposited LDLc can be removed from the site by HDL. But when triglycerides increases it is associated with decrease in HDL, this decrease in HDL cannot effectively remove LDL, thus helping atherosclerosis.LDLc as such cannot initiate inflammatory response. It needs to be oxidized, which is .brought about by free oxygen radicals. The rise in oxidized LDL in sub -endothelial layer increases the oxidized LDL in the blood and is a highly sensitive index of atherosclerosis. Oxidized LDL causes release of Vascular Cell Adhesion Molecule from endothelial cells. This causes adhesion of monocytes to endothelial layer. Oxidized LDL also causes release of Monocyte Chemo Attractant Protein1 (MCP1) which facilitates entry of monocytes into sub endothelia l tissue. Here they converted into macrophages .They absorb cholesterol to form foam cells. The oxidized LDL also gets absorbed on to the surface receptors of the scavenger cells. These foam cells accumulate beneath the sub -endothelial layer of the arteries to form fatty streaks. The foam cells then liberate some factors which cause migration and proliferation of smooth muscle cells; these surround the foam cells and induce formation of collagen. The foam cells eventually die off liberating cholesterol in the cavity. Thus atheroma has a central core of cholesterol with a fibrous cap. http://images.medscape.com/pi/editorial/cmecircle/2002/2036/figure-2-large.jpg The free oxygen radicals cause endothelial dysfunction by inactivating released nitric oxide and inhibiting nitric oxide synthesis. The endothelial dysfunction contributes to atherosclerosis since normal endothelium releases nitric oxide which in turn inhibits VCAM. Diabetes, smoking, hyper tension, hyper homocysteinemia and increased LDL cholesterol all contribute to oxidative stress. Thus atherosclerotic artery disease begins with a fatty streak on the blood vessel surface which may enlarge to form fatty plaque. The subsequent narrowing of the arteries may eventually lead to disruption of the plaque and to thrombus formation with further reduction of blood flow, thus paving the way for acute myocardial infarction. Complete obstruction of blood results in myocardial necrosis within 20 minutes with maximum irreversible injury occurring within 6 hours. So the restoration of blood flow to the damaged myocardium within two hours but not later than 6 hours can salvage it. http://labs.ansci.uiuc.edu/meatscience/Library/309%20lipid%20transport.gif http://medtech.hcu.ac.th/pic/lipid.jpg Lipid profile Lipid profile is a group of tests to find out the level of LDL, VLDL, HDL, Triglycerides, Total Cholesterol, and T.Cholesterol / HDL ratio. This is used alone or in combination with other risk factors like age, gender, BP, smoking in Framingham score or along with other biomarkers in predicting the risk of a/c Myocardial Infarction. This is a simple blood test .Patient is advised to come on empty stomach

A piece of writing of Graphene Essay Example | Topics and Well Written Essays - 1500 words

A piece of writing of Graphene - Essay Example The interesting thing about graphene is that it has huge power along with adequate electrical conductivity and elasticity. Graphene is actually a significantly huge aromatic molecule. Graphite can get its crystalline form by combining a number of sheets of graphene together. Graphene is regarded as the most fundamental structural component of a few carbon allotropes. For example, graphene lays the basis of graphite, fullerenes, charcoal, etc. The discovery of graphene has immense significance as various new possibilities of research in the area of physics have opened up. Researches in graphene have also helped in opening up huge scopes of its application in high-tech fields. Graphene is considered to be one of the most potential and adaptable components that have ever discovered in the area of physics. (Geim; 2009; Sakamoto 2009). The production of Graphene: Graphene can be separated from graphite as an isolated plane of carbon atoms. People now know that a minute portion of graphene sheet can be produced by abrading graphite. For example, one can get a tiny piece of graphene sheet when one draws a line on paper with a pencil. (Geim; 2009). During the year of 2008, the production of graphene used to be done by exfoliation. This graphene produced through such exfoliation was considered to be one of the most costly components in this world as this component which so small that can be placed on a tiny portion of the cross section of human hair did costs around as much as $1000 in 2008. Since, 2008, the process of exfoliation has been increased and various companies are now selling graphene in huge amount. Researchers have also discovered cheaper version of graphene (Segal, 2009). For example, Korean researchers have produced cheap graphene through the process of transfer of nickel. Graphene can, in fact, be produced by employing different types of methods. Some of the production processes of graphene are listed below: Producing Graphene through Drawing Method: The drawing method is actually a modified version of exfoliation method. Earlier, in this method, a solid tape was used to repetitively divide crystals of graphite into more thin prices to form graphene. The extremely thin flakes of Graphene then used to be dissolved in liquid acetone and after a few steps they were to be sedimented. Over time, the technique of drawing graphene from graphite has been simplified. Particularly, major modification has been done in the step of disposition. Instead of making graphene floating in acetone, the scientists have started to use the method of dry disposition of flakes. (Geim and Novoselov, 2007) Production through heating silicon carbide: Another popular process of producing graphene is heating silicon carbide at a high temperature in order to reduce it to graphene. In this process silicon carbide is heated at more that 1100 degree centigrade. In this method, the dimension of the graphene produced depends on the dimension of the silicon wafer. The face of the silicon wafer which is utilized for the formation of graphene, has significant capacity to influence the density and the level of mobility of graphene. If graphene is produced using this method, then a number of properties of graphene can clearly be visualized. For example, in the graphene produced through heating silicon carbide a kind of feeble anti-localization of the component can be