79 research outputs found
Resolving the strange behavior of extraterrestrial potassium in the upper atmosphere
It has been known since the 1960s that the layers of Na and K atoms, which occur between 80 and 105 km in the Earth's atmosphere as a result of meteoric ablation, exhibit completely different seasonal behavior. In the extratropics Na varies annually, with a pronounced wintertime maximum and summertime minimum. However, K varies semiannually with a small summertime maximum and minima at the equinoxes. This contrasting behavior has never been satisfactorily explained. Here we use a combination of electronic structure and chemical kinetic rate theory to determine two key differences in the chemistries of K and Na. First, the neutralization of K+ ions is only favored at low temperatures during summer. Second, cycling between K and its major neutral reservoir KHCO3 is essentially temperature independent. A whole atmosphere model incorporating this new chemistry, together with a meteor input function, now correctly predicts the seasonal behavior of the K layer
Anticoagulant, Antiherpetic and Antibacterial Activities of Sulphated Polysaccharide from Indian Medicinal Plant Tridax procumbens L. (Asteraceae)
A human-like H1N2 influenza virus detected during an outbreak of acute respiratory disease in swine in Brazil
ISU FLUture: a veterinary diagnostic laboratory web-based platform to monitor the temporal genetic patterns of Influenza A virus in swine
Intraoperative adjuncts in surgery for primary hyperparathyroidism
PURPOSE: This paper is a review of the evidence base to produce recommendations for the use of intraoperative parathyroid hormone (PTH), radioguided parathyroidectomy (RGP), methylene blue (MB), frozen section, and intraoperative neuromonitoring during surgery for primary hyperparathyroidism (PHPT). MATERIALS AND METHODS: A Medline keyword search of English-language articles led to the production of a draft document, subsequently revised by committee, containing levels of evidence and the grading of recommendations as proposed by the Agency for Healthcare Research and Quality. RESULTS: Literature review provides the basis for clear recommendations on the use of intraoperative PTH at surgery for PHPT. There is little evidence to support the use of RGP, MB, routine frozen section, and intraoperative neuromonitoring
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