i am a student, want to some thing so cool!. Some thing inovative!. i want 2 show world what i am i am though hardworking person i think i dont use my intelegence when wanted. i have decided, i showed learn n do something for my progress from 2day so that one day i feel proved of myself.


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ARTTURI LLMARI VIRTANEN

ARTTURI LLMARI VIRTANEN Born 15 Jan 1895; died 11 Nov 1973. 
Finnish biochemist whose investigations directed toward improving the production and storage of protein-rich green fodder, vitally important to regions characterized by long, severe winters, brought him the Nobel Prize for Chemistry in 1945. The AIV method, named for his initials, was storing green fodder in an acid medium to prevent spoilage and retain nutritious nitrogenous material. He found that a mixture of hydrochloric and sulfuric acid was adequate as long as its strength was kept within certain precise limits (a pH of about four). In 1929, he found that cows fed such silage gave milk indistinguishable in taste from that of cows fed on normal fodder, while as rich in vitamins A and C.

R.B.BRAITHWAITE Born 15 Jan 1900; died 21 Apr 1990. 
Richard Bevan Braithwaite was a British philosopher, who trained in physics and mathematics, but turned to the philosophy of science. He examined the logical features common to all the sciences. Each science proceeds by inventing general principles from which are deduced the consequences to be tested by observation and experiment. Braithwaite was concerned with the impact of science on our beliefs about the world and the responses appropriate to that. He wrote on the statistical sciences, theories of belief and of probability, decision theory and games theory. He was interested in particular with the laws of probability as they apply to the physical and biological sciences.

JANUARY 15 - BIRTHS

EDWARD TELLERBorn 15 Jan 1908; died 9 Sep 2003  
Hungarian-born American nuclear physicist who participated in the production of the first atomic bomb (1945) and who led the development of the world's first thermonuclear weapon, the hydrogen bomb. After studying in Germany he left in 1933, going first to London and then to Washington, DC. He worked on the first atomic reactor, and later working on the first fission bombs during WW II at Los Alamos. Subsequently, he made a significant contribution to the development of the fusion bomb. His work led to the detonation of the first hydrogen bomb (1952). He is sometimes known as "the father of the H-bomb." Teller's unfavourable evidence in the Robert Oppenheimer security-clearance hearing lost him some respect amongst scientists.

Today In Science History, The people and events of today

2008 is the 50th anniversary of the first integrated circuit, demonstrated on 12 Sep 1958 by its inventor, Jack Kilby, to his supervisor at Texas Instruments.
2008 is the 100th anniversary of the first major Middle East oil strike made on 26 May 1908 at Masjid-i-Suleiman, Persia.
2008 is the 200th anniversaries of the first isolation of the elements barium, strontium, calcium and magnesium, by Humphry Davy in England.


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IBM in sales alliance with Japan's Ricoh: paper (Reuters)

IBM in sales alliance with Japan's Ricoh: paper (Reuters) Reuters - IBM and Japanese office equipment maker Ricoh Co Ltd (7752.T) will start sharing each other's sales network this year and promote their servers and printers together, the Nikkei business daily said on Thursday.

Lecture I Cardiovascular System

Lecture I 
Cardiovascular System
HeartThe heart (Latin cor) is a hollow, muscular organ that pumps blood through the blood vessels by repeated, rhythmic contractions. The term cardiac means "related to the heart", from the Greek kardia for "heart".


 
StructureIn the human body, the heart is normally situated slightly to the left of the middle of the thorax, underneath the sternum (breastbone). It is enclosed by a sac known as the pericardium and is surrounded by the lungs. In normal adults, its mass is 250-350 g, but extremely diseased hearts can be up to 1000 g in mass. It consists of four chambers, the two upper atria (singular: atrium) and the two lower ventricles.


 
A septum divides the right atrium and ventricle from the left atrium and ventricle, preventing blood from passing between them. Valves between the atria and ventricles (atrioventricular valves) maintain coordinated unidirectional flow of blood from the atria to the ventricles.
The function of the right side of the heart (see right heart) is to collect deoxygenated blood from the body and pump it into the lungs so that carbon dioxide can be dropped off and oxygen picked up. This happens through a process called diffusion. The left side (see left heart) collects oxygenated blood from the lungs and pumps it out to the body. On both sides, the lower ventricles are thicker than the upper atria.
Oxygen-depleted or deoxygenated blood from the body enters the right atrium through two great veins, the superior vena cava, which drains the upper part of the body and the inferior vena cava that drains the lower part. The blood then passes through the tricuspid valve to the right ventricle. The right ventricle pumps the deoxygenated blood to the lungs, through the pulmonary artery. In the lungs gaseous exchange takes places and the blood releases carbon dioxide into the lung cavity and picks up oxygen. The oxygenated blood then flows through pulmonary veins to the left atrium. From the left atrium this newly oxygenated blood passes through the mitral valve to enter the left ventricle. The left ventricle then pumps the blood through the aorta to the entire body. Even the lungs take some of the blood supply from the aorta via bronchial arteries.
The left ventricle is much more muscular (1.3 - 1.5 cm thick) than the right (0.3 - 0.5 cm thick) as it has to pump blood around the entire body, which involves exerting a considerable force to overcome the vascular pressure. As the right ventricle needs to pump blood only to the lungs, it requires less muscle.
Even though the ventricles lie below the atria, the two vessels through which the blood exits the heart (the pulmonary artery and the aorta) leave the heart at its top side.
The contractile nature of the heart is due to the presence of cardiac muscle in its wall, which can work continuously without fatigue. The heart wall is made of three distinct layers. The first is the outer epicardium, which is composed of a layer of flattened epithelial cells and connective tissue. Beneath this is a much thicker myocardium made up of cardiac muscle. The endocardium is a further layer of flattened epithelial cells and connective tissue which lines the chambers of the heart.
The blood supply to the heart itself is supplied by the left and right coronary arteries, which branch off from the aorta.
The cardiac cycleThe function of the heart is to pump blood around the body. Every single beat of the heart involves a sequence of events known as the cardiac cycle, which consists of three major stages: atrial systole, ventricular systole and complete cardiac diastole. The atrial systole consists of the contraction of the atria and the corresponding influx of blood into the ventricles. Once the blood has fully left the atria, the atrioventricular valves, which are situated between the atria and ventricular chambers, close. This prevents any backflow into the atria. It is the closing of the valves that produces the familiar beating sounds of the heart, commonly referred to as the "lub-dub" sound.
 

 

The ventricular systole consists of the contraction of the ventricles and flow of blood into the circulatory system. Again, once all the blood empties from the ventricles, the pulmonary and aortic semilunar valves close. Finally complete cardiac diastole involves relaxation of the atria and ventricles in preparation for refilling with circulating blood.
Regulation of the cardiac cycleCardiac muscle is self-exciting. This is in contrast with skeletal muscle, which requires either conscious or reflex nervous stimuli. The heart's rhythmic contractions occur spontaneously, although the frequency or heart rate can be changed by nervous or hormonal influences such as exercise or the perception of danger.
The rhythmic sequence of contractions is coordinated by the sinoatrial and atrioventricular nodes. The sinoatrial node, often known as the cardiac pacemaker, is located in the upper wall of the right atrium and is responsible for the wave of electrical stimulation (See action potential) that initiates atria contraction. Once the wave reaches the atrioventricular node, situated in the lower right atrium, it is conducted through the bundles of His and causes contraction of the ventricles. The time taken for the wave to reach this node from the sinoatrial nerve creates a delay between contraction of the two chambers and ensures that each contraction is coordinated simultaneously throughout all of the heart. In the event of severe pathology, the Purkinje fibers can also act as a pacemaker; this is usually not the case because their rate of spontaneous firing is considerably lower than that of the other pacemakers and hence is overridden.
Other physiological functionsThe heart also secretes ANF (atrial natriuretic factor), a powerful peptide hormone, that affects the blood vessels, the adrenal glands, the kidneys and the regulatory regions of the brain to regulate blood pressure and volume.
Diseases and treatmentsThe study of diseases of the heart is known as cardiology. Important diseases of the heart include:
Coronary heart disease is the lack of oxygen supply to the heart muscle; it can cause severe pain and discomfort known as Angina. A heart attack occurs when heart muscle cells die because blood circulation to a part of the heart is interrupted. Congestive heart failure is the gradual loss of pumping power of the heart. Endocarditis and myocarditis are inflammations of the heart. Cardiac arrhythmia is an irregularity in the heartbeat. It is sometimes treated by implanting an artificial pacemaker Congenital heart defects. If a coronary artery is blocked or narrowed, the problem spot can be bypassed with coronary artery bypass surgery or it can be widened with angioplasty.
Beta-blockers are drugs that lower the heart rate and blood pressure and reduce the heart's oxygen requirements. Nitroglycerin and other compounds that give off nitric oxide are used to treat heart disease as they cause the dilation of coronary vessels.
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