Thursday, June 21, 2012
Scientists, including an Indian researcher, have found a previously unknown stem cell which is the real culprit behind heart attacks, a landmark finding which, they say, could revolutionise treatments for the cardiac disease. Until now, it has been thought that vascular health problems were triggered by smooth muscle cells, but a team at the University of California in Berkeley identified a previously unknown stem cell, which causes the arteries to harden when it multiplies. The groundbreaking work is set to completely change how heart attacks and strokes are treated, dramatically cutting the number of deaths, the researchers said. “For the first time, we are showing evidence that vascular diseases are actually a kind of stem cell disease,” said Professor Song Li, who led the research. “This work should revolutionise therapies for vascular diseases because we now know that stem cells rather than smooth muscle cells are the correct therapeutic target,” Prof. Li was quoted as saying by the Daily Mail. “This is groundbreaking and provocative work, as it challenges existing dogma,” added his colleague Dr. Deepak Srivastava. Heart attacks are the most common reason for people to need emergency treatment. More than 150,000 people a year have a stroke. Strokes occur when the blood supply to part of the brain is cut off, while heart attacks happen when the supply of blood to the heart is blocked, usually by a blood clot. According to the researchers, who detailed their findings in the journal Nature Communications, the newly discovered vascular stem cells are multipotent — or capable of changing into various cell types, including smooth muscle, nerve, cartilage, bone and fat cells — explaining why previous studies misidentified the cells involved in vessel clogs. “In the later stages of vascular disease, the soft vessels become hardened and more brittle,” said Prof Li. “Previously, there was controversy about how soft tissue would become hard. The ability of stem cells to form bone or cartilage could explain this calcification of the blood vessels,” Prof. Li added.
at 2:32 AM posted by SCIENCE NEWS
If you have turned into a heavy tea drinker influenced by the health benefits boasted by recent studies, you need to rethink, as a new long-term research has claimed seven cups or more of the beverage a day could raise the risk of prostate cancer in men. The warning comes from University of Glasgow researchers who tracked more than 6,000 men for four decades and found that those who drank seven or more cups of tea daily had a 50 per cent higher risk of contracting the disease than men who took three or fewer. Their findings, published in the journal Nutrition and Cancer, counter the previous research, which have suggested that tea-drinking lowers the risk of cancer, as well as heart disease, diabetes and Parkinson’s disease. In the new study, which was began in 1970, participants aged between 21 and 75 were asked to complete a questionnaire about their usual consumption of tea, coffee and alcohol as well as their smoking habits and general health. They also had to attend a screening examination. Just under a quarter of the over 6,000 men were heavy tea drinkers, consuming seven or more cups a day. Of them, 6.4 per cent developed prostate cancer over the next 37 years. The researchers also found that the subjects who drank the most tea were often teetotal and led healthy lifestyles. As a result, they may have been at a lower risk of death from “competing causes”, effectively giving them more time to develop prostate cancer, they said. “Most previous studies have shown either no relationship with prostate cancer for black tea, or some preventive effect of green tea,” lead study author Kashif Shafique was quoted as saying by the Daily Mail. “We don’t know whether tea itself is a risk factor or if tea-drinkers are generally healthier and live to an older age, when prostate cancer is more common anyway,” Dr Shafique said. “However, we did adjust for these differences in our analysis and still found that men who drank the most tea were at greater risk of prostate cancer,”he added. Past research has found health benefits from flavonoids antioxidant compounds in tea that are thought to control inflammation, reduce excess blood clotting and limit narrowing of the arteries. Of seven previous studies on black tea and prostate cancer, four found a potentially protective effect while the remainder found no effect either way. Dr Kate Holmes, head of research at The Prostate Cancer Charity, said: “Whilst it does appear that those who drank seven or more cups of tea each day had an increased risk of developing prostate cancer, this did not take into consideration family history or any other dietary elements other than tea, coffee and alcohol intake.
at 2:31 AM posted by SCIENCE NEWS
Heated bulk metallic objects turning red should be differentiated from some metals showing different colours when burnt either as vapours in a flame or as fine powder particles, wafers, shavings ex: magnesium fine powder/tape used in sparklers generating lot of brilliant yellow flashes. The former is described by the process of incandescence while the latter can be described using several intra-atomic electronic transitions. Basically incandescence is a process of generating glow-light associated with heating. The popular examples being burning of wood and a glow from a conventional tungsten lamp. In the lamp, electric current passing through the metallic tungsten filament encounters resistance for the flow of electrons which causes lot of Joule heating appearing as glow-light of the filament. A bulk metallic object when heated reaches high temperature and starts glowing. For any hot body, the colour of the glow can be used as a measure of its body temperature, known by the term correlated colour temperature (T) given in relation to black body radiation with the latter being the perfect emitter. It should be borne in mind that the colour temperature is more a measure of glow/emission colour which can be related to that of the black body when its temperature is raised to that indicated temperature. The correlated colour temperature (T) of a hot body and the colour of the glow — emission wavelength λ (lambda) bear inverse relation through a law known as Wien’s displacement law. That is warm colours (yellow/red) having longer wavelengths have lower colour temperature T, while cool colours ( towards blue) show higher T As an example, a yellow glow from a tungsten lamp or burning of candle show colour temperatures T in the range of 2,500-3,500 K, degree Kelvin while a blue light or /sky has a colour temperature of 10,000 K. Obviously, even a red colour emission from a heated metallic object calls for a very high temperature ( approximately 2,000 deg C) which is closer to /surpassing melting points of most of the common metals available. Turning to explain the absence of cool colour glow from heated metals (that is shifting towards blue emission) calls for still higher colour temperatures which are many times higher than the melting points of metals. But further raising the temperature would readily render the most of metals vaporized /unstable.
at 2:26 AM posted by SCIENCE NEWS
In Kerala, even though 60 per cent of the milk requirement is met by procurement from other states like Tamil Nadu, Karnataka and Maharashtra, cattle rearing is fast declining due to high cost of production, labour shortage and shrinking land. Heavy dependence on other states for raw materials pushes up the cost of concentrate feeds. “Dry straw (hay) used to feed cattle has become scarce due to decline in area under rice cultivation. It becomes a dire necessity for dairy farmers to start growing green fodder (grass) if they desire to run their unit profitably,” says Dr.S. Prabhu Kumar, Zonal Project Director, ICAR, Zonal Project Directorate, Bangalore. Grow own fodder And he adds that mere distribution of milch animals by the Government is of no use to farmers. Along with the animals they must be also made aware of the importance of growing their own fodder for the animals. Buying several commercial feeds available in the markets today is not profitable for a small farmer and is sure to burn a hole in their pocket, according to him. Take the case of the Koipuram Milk society established on the banks of river Pampa nearly 20 years back by one Mr. Gopalakrishnan Nair to prevent dairy farmers from being exploited by middlemen who were not providing timely price for the milk supplied. During peak production time farmers used to get only Rs.2.40 per litre of milk while the market price was Rs. 6 per litre. The society was initially started with 400 members and 1,500 litres of milk was sent daily to the milk marketing federation of Kerala for further processing and sales. The price was fixed by the society. Cultivated acreage Since 1995 the society encouraged fodder production for its members and introduced different fodder grasses like Congo Signal, Gunnie grass, Hybrid Napier like CO1, CO2 and CO3 in the area. By 2009, 150 hectares in the region were brought under different types of fodder cultivation. “We brought four cuttings of CO4 Hybrid Napier grass from Tamil Nadu Agriculture University Coimbatore, and multiplied it in our KVK farm. “Today our farmers are selling this fodder to several private farms in Kollam, Allapuzha, Kottayam and Idukki Districts. On an average 800-1,200 Kg of green fodder is being sold today by the farmers of this society,” says Dr. C. P. Robert, Programme Co-ordinator, CARD-KVK (Christian agency for rural development- Krishi Vigyan Kendra), Pathanamthitta district, Kerala. CARD KVK has been in the forefront of fodder promotion in the Pathanamthitta district and has been conducting many trials to identify suitable forage varieties for the district. Dairy farmers are given training on scientific fodder management practices as and when the need arises. Feeding ratio “Feeding one bundle (15Kg) of CO4 grass has been found to increase milk yield by almost 200 ml per cow. Seeing this superior growth characteristic, farmers are replanting CO4 variety today and it has almost replaced the previous CO3 variety,” says Dr.Robert. Till date several lakh cuttings of this grass have been sold to different agriculture project areas in Kerala. Marketing Farmers are selling this fodder for Rs1.30 a kg and are able to harvest 7-8 cuttings a year (the cuttings may vary with the availability of water). Many are able to get an average yield of 270 tonnes per hectare and earn Rs. 15,000 as net profit annually. The society also generates 300 days of employment through this activity a year, according to Dr. Robert. For more details contact Dr. C. P. Robert, Programme Co-ordinator, CARD-Krishi Vigyan Kendra-Pathanamthitta District, Kolabhagam Post Office, Tiruvalla(Via), Pathanamthitta Dist, Kerala, email: email@example.com, Phones:0469- 2662094 and 2661821, mobile:09447139300.
at 2:24 AM posted by SCIENCE NEWS
Researchers from the University of Bristol and other institutions have found the “first unequivocal” chemical evidence of dairying practices by Saharan people about 5,000 years ago — at a time when the region was in a humid phase and had plenty of plant cover. The story so far Researching the earliest evidence of dairying has so far been confined to Europe, Near East and Eurasia. This is the first time an attempt is made to study African samples. The results are published today (June 21) in Nature. Till date evidence of domestication of cattle, sheep and goats came from faunal samples. But faunal remains have been “highly fragmentary and poorly preserved.” Reconstructing evidence of herding has therefore been difficult. Even indirect evidence of dairying is “missing.” Of course, rock paintings and engravings have provided some compelling indirect evidence. The researchers therefore turned to molecular and isotope analysis of absorbed food residues found on potsherds to know the details. The rationale is simple: analysing food residues is a sure way of understanding diet and subsistence practices of humans a few thousand years ago. Making the study possible has been the exemplary preservation of absorbed organic residues, particularly lipids, on potsherds. This is unlike in the case of European sites where only 40 per cent of potsherds provided any evidence of lipids, and that to at very low concentrations. “This remarkable preservation [in the case of African samples] is likely to be related to the extremely arid conditions prevailing in the region” in the last hundreds of years. The researchers used carbon 13 isotopic ratios to study the major alkanoic acids of milk fat. The lipids belonged to three categories — “high abundance” of C16:0 and C18:0 (lipid numbers) fatty acids derived from degraded animals fats. There were carbon isotopes (C13 to C18) which are demonstrative of “bacterial origin” and diagnostic of “ruminant animal fats.” In the second category, the carbon isotopes found were diagnostic of plant oils and a certain kind of wax of vascular plants. The third type of residue indicates the “drying reaction of plant oils,” and reflects either “processing of both plant and animal products in the same vessel or the multiuse of the vessels.” Of the three types, only those indicative of degraded animal fats were taken up for detailed analysis. Compared with present day animal fats, about 50 per cent of lipid samples recovered from the potsherds fall within or on the edge of isotopic range of dairy fats. About 33 per cent fall within the isotope range for ruminant adipose fats. “The unambiguous conclusion is that the appearance of dairy fats correlates with the abundant presence of cattle bones in the cave deposits, suggesting a full pastoral economy,” they write. They also found unequivocal evidence for “extensive processing of dairying products” in pottery in the Libyan Sahara between 5,200-3,800 years ago. This confirms that “milk played an important part in the diet of these prehistoric pastoral people.” This is quite surprising considering the fact that these people were able to consume milk despite suffering from lactose intolerance. The study thus provides a window to the “evolutionary context for the emergence of lactase persistence in Africa.”
at 2:21 AM posted by SCIENCE NEWS