01-09-2011 1.Antibiotic resistance is ancient in origin Since the discovery of antibiotics has being recent, no more than 70 years ago, antibiotic resistance seen in microbes should be a “modern phenomenon.”By extension, any microbes older than 70 years should be “highly susceptible to antibiotics,” and hence should never have shown antibiotic resistance.But a study published in Nature , rocks the very foundation of our understanding of antibiotic resistance. It provides sufficient evidence to prove that antibiotic resistance is a “natural phenomenon,” and existed in microbes predating antibiotic discovery by man. Earlier studies had estimated that origin of natural antibiotics dates back from 2 billion years to 40 million years ago. If natural antibiotics were that old, can antibiotic resistance be far behind? Antibiotic resistance seen in microbes (bacteria and fungi) should not be a surprise as they produce antibiotics naturally. “Roughly 80 per cent of antibiotics currently in the market are derived either directly or indirectly (e.g. by modification of naturally occurring structures) from bacteria that are found in the environment, mostly the soil,” What makes the findings all the more surprising is that all the genes extracted from nearly 30,000-year-old microbes reveal the presence of resistance to many commonly used antibiotics — tetracycline, beta-lactam, glycopeptides and even vancomycin. In clinical settings, vancomycin resistance was first seen in pathogenic bacteria (enterococci) only in the late 1980s! If bacteria already had antibiotic resistance towards drugs like tetracycline, Vancomycin, beta- lactum etc used today, why did it take some time for antibiotic resistance to show up in clinical settings? “We need to differentiate resistance in pathogenic bacteria here from [benign] environmental bacteria that do not usually cause disease,” . “Pathogens are generally quite antibiotic sensitive unless they acquire resistance genes from other sources. “The evidence suggests that environmental bacteria are the reservoir for these genes. THE study demonstrates that these benign bacteria have expressed these genes for millennia.” The widespread prevalence of antibiotic resistance seen today “is inconsistent with a hypothesis of contemporary emergence,”“instead it suggests a richer natural history of resistance.” So what is the role of clinically formed resistance? “The clinical (and other use) of antibiotics provides the selective pressure to select for resistance genes that may be mobilised from environmental bacteria,”. What needs to be done If this is indeed true and correct, then there is an overwhelming need to have in place a more responsible planning and management mechanism of existing antibiotics and newer ones. “we need two things: 1) more drug candidates, and 2) better use of existing antibiotics e.g. reduced use in agriculture, and tight controls in medicine.” 2. “Underground ‘river' is fed all along its course:” Hamza Valiya M. Hamza has discovered a 6,000 km-long underground ‘river' in Brazil at a depth of 4 km. Hestarted his career in 1966 as a Senior Scientific Assistant at the National Geophysical Research Institute (NGRI) in Hyderabad, and is currently Head of the Geothermal Laboratory of the National Observatory, Rio de Janeiro, Brazil.
The 6,000-km Hamza river flows under the Amazon, an India connect to the world's longest river. And Valiya Mannathal Hamza, the Brazil-based scientist from Kerala who helped in the discovery of the underground river with his student, says he is thrilled their research has attracted such attention.
The Indian-origin professor at the National Observatory, Rio de Janeiro, has just been bestowed the rare honour of having the underground river flowing under the Amazon being named after him.Brazilian scientists, who discovered the existence of the underground river last week, took the decision to name it after Hamza, in a tribute to his four-decade work in the region. The discovery was made possible thanks to research work performed at 241 wells that an oil company drilled in the Amazon region in the 1970s while prospecting for crude, according to the study.The subterranean river runs at a depth of about 4,000 metres along a course similar to that of the Amazon. The flow is just three percent of that of the Amazon river, which has its headwaters in the Peruvian jungle, empties into the Atlantic in northern Brazil and at 6,800 km is considered to be the world's longest river.
Hamza, who did his BSc in 1962 and MSc in 1964 from the University of Kerala in Thiruvananthapuram, moved to Canada to do his PhD in 1973. 3.Breakthrough in hydrogen fuel cells Hydrogen makes a great fuel because of it can easily be converted to electricity in a fuel cell and because it is carbon free. The downside of hydrogen is that, because it is a gas, it can only be stored in high pressure or cryogenic tanks. A team of University of Southern California scientists has developed a robust, efficient method of using hydrogen as a fuel source. In a vehicle with a tank full of hydrogen, “if you got into a wreck, you'd have a problem,” A possible solution is to store hydrogen in a safe chemical form. Earlier this year, figured out a way to release hydrogen from an innocuous chemical material — a nitrogen-boron complex, ammonia borane — that can be stored as a stable solid, says a University of Southern California. Now the team has developed a catalyst system that releases enough hydrogen from its storage in ammonia borane to make it usable as a fuel source. Moreover, the system is air-stable and re-usable, unlike other systems for hydrogen storage on boron and metal hydrides. The research was published this month in the Journal of the American Chemical Society . The system is sufficiently lightweight and efficient to have potential fuel applications ranging from motor-driven cycles to small aircraft. 4.Firing lasers to make rain? Researchers have used a powerful laser to produce water droplets in the air, a step that could ultimately help trigger rainfall. While nothing can produce a downpour from dry air, the technique, called laser-assisted water condensation, might allow some control over where and when rain falls if the atmosphere is sufficiently humid. Records from 133 hours of firings revealed that intense pulses of laser light created nitric acid particles in the air that behaved like atmospheric glue, binding water molecules together into droplets and preventing them from re-evaporating.
Within seconds, these grew into stable drops a few thousandths of a millimetre in diameter: too small to fall as rain, but large enough to encourage the scientists to press on with the work. “We have not yet generated raindrops — they are too small and too light to fall as rain. To get rain, we will need particles a hundred times the size, so they are heavy enough to fall,” said Jerome Kasparian, a physicist at the University of Geneva. A report on the tests appears in the journal Nature Communications . With improvements, shooting lasers into the sky could either help trigger or prevent showers. One possibility might be to create water droplets in air masses drifting towards mountains. The air would cool as it rose over these, causing the water droplets to grow and eventually fall. An alternative might be to stave off an immediate downpour by creating so many tiny droplets in the air that none grew large enough to fall. “Maybe one day this could be a way to attenuate the monsoon or reduce flooding in certain areas,”. 5.Bio fertilizers for tree cultivation Excessive use of chemical fertilizers has generated several environmental problems. To overcome these, bio fertilizers can be used as they are natural, beneficial, eco friendly and user friendly. They are considered important in growth improvement and establishment of forest tree seedlings as the media used to raise seedlings in nursery as well as planting sites are generally low in nutrients and beneficial microbial populations. It is very essential to improve the seedling health and quality planting stock of every forest tree species at the nursery level for successful establishment in the field. The following group of bacteria and fungi are major bio fertilizers being used in tree cultivation. Arbuscular mycorrhizal (AM) fungi are symbiotic associations between tree roots and soil fungi that play a key role in nutrient cycling in the ecosystem and also protect plants against environmental stress. Nitrogen fixing bacteria Some bacteria are capable of nitrogen fixation from the atmospheric Nitrogen pool. The major types of N2 fixing bacteria are Azospirillum, Rhizobium , and Frankia . Azospirillum is free living in soils so that it can be cultured and produced in artificial medium only. It can be used at the rate of 5 gm / tree seedlings of all tree crops. Rhizobium is host specific nitrogen fixing bacteria normally associated with leguminous trees. About 5g of rhizobium /tree seedlings of leguminous tree crops is required for nitrogen fixation and growth improvement. Phosphate solubilising Most of the Indian soils are deficient in phosphorus and its requirement is met by the addition of phosphate fertilizers in the form of aluminium phosphate or iron phosphate. But these fertilizers are becoming costly and may have adverse effect on forest trees. Hence, phosphate solubilising bacteria have to be used. PSB also can be used at the rate of 5gm to all tree seedlings and are capable of solubilising 50-60 per cent of rock phosphorus in the soil. Care should be taken while using biofertilizers. They should not be mixed with chemical fungicides or insecticides and are to be used with prolonged shelf life forms. 6.Hydrogen fuel from sunlight Scientists have determined that an inexpensive semiconductor material can be ‘tweaked' to generate hydrogen from water using sunlight.
Using state-of-the-art theoretical computations, the University of Kentucky-University of Louisville team demonstrated that an alloy formed by a 2 per cent substitution of antimony (Sb) in gallium nitride (GaN) has the right electrical properties to enable solar light energy to split water molecules into hydrogen and oxygen, a process known as photoelectrochemical (PEC) water splitting. When the alloy is immersed in water and exposed to sunlight, the chemical bond between the hydrogen and oxygen molecules in water is broken. The hydrogen can then be collected. 7.Leucine saves muscle, burns fat of climbers At high altitudes, fat and muscle loss occurs not only when climbing, but also at rest. Research on Mt. Everest climbers shows that an amino acid, leucine, may help climbers burn fat while keeping their muscle tissue intact. 8.New views of Saturn's moon Hyperion snapped NASA's Cassini spacecraft captured new views of Saturn's moon Hyperion during its encounter with a cratered body recently. This was Cassini's second closest encounter. 9.plan to acquire Howitzers hits a roadblock Indian Army's plans to acquire Ultra Light Howitzers (ULH) for its artillery units has again hit a hurdle with Defence Ministry seeking a legal opinion before going ahead with the deal in view of an order passed by the Delhi High Court in May this year.
Defence Ministry has asked Law Ministry's opinion as one of the companies involved in the deal, Singapore Technologies, was not allowed to take part in defence contracts by the government after it was named in a CBI FIR in the Ordnance Factory scam a few years ago. 10.ISRO to build powerful communication satellites The Indian Space Research Organisation (ISRO) plans to build a new class of powerful communication satellites that packs more capacity and new technologies, its Chairman K Radhakrishnan said.
This kind of spacecraft would handle larger amount of power and accommodate more number of transponders in the same satellite, ISRO planned to incorporate new technologies in them and get into higher bands. "Today, we are at Ku band. We want to get into Ka band and even higher band.
This is one of the priorities (in the coming five-year plan (which starts in April next year)", Radhakrishnan, who is also Chairman of Space Commission and Secretary in the Department of Space, said. "In remote sensing (satellite field), we have to get into environmental studies and climate change studies. This is one requirement, new requirement (in the next five-year plan)," he said.
PREPARATION AU COLOSCANNER A L’AIR Les jours qui précèdent l’examen : - Se procurer auprès de votre pharmacien les produits nécessaires à la préparation de votre - Suivre les instructions de la préparation colique (ci-jointe). Le jour de l’examen : - Le matin, restez à jeun : ne pas boire, ni manger, ni fumer. - N’oubliez pas la lettre de votre médecin, vos an
Einleitung Bisphosphonate wurden erstmals 1865 syn-thetisiert [1] und bei zahlreichen industriellenProzessen z. B. als Wasserenthärter oderAntikorrosiva angewendet. Nach den grund-legenden Arbeiten von Fleisch [2, 3] zurknochenmineralisierenden und osteotropenWirkung der Substanzen erfolgte ihre Ent-wicklung zur Therapie metabolischer Kno-chenerkrankungen. Die Indikati