Mount st. Helens ash from the 18 may 1980 eruption: chemical, physical, mineralogical, and biological properties     

Fruchter JS  Robertson DE  Evans JC  Olsen KB  Lepel EA  Laul JC  Abel KH  Sanders RW  Jackson PO  Wogman NS  Perkins RW  VAN Tuyl HH  Beauchamp RH  Shade JW  Daniel JL  Erikson RL  Sehmel GA  Lee RN  Robinson AV  Moss OR  Briant JK  Cannon WC 《Science (New York, N.Y.)》1980,209(4461):1116-1125

Samples of ash from the 18 May 1980 eruption of Mount St. Helens were collected from several locations in eastern Washington and Montana. The ash was subjected to a variety of analyses to determine its chemical, physical, mineralogical, and biological characteristics. Chemically, the ash samples were of dacitic composition. Particle size data showed bimodal distributions and differed considerably with location. However, all samples contained comparable amounts of particles less than 3.5 micrometers in diameter (respirable fraction). Mineralogically, the samples ranged from almost totally glassy to almost totally crystalline. Crystalline samples were dominated by plagioclase feldspar (andesine) and orthopyroxene (hypersthene), with smaller amounts of titanomagnetite and hornblende. All but one of the samples contained from less than 1 percent to 3 percent free crystalline silica (quartz, trydimite, or cristobalite) in both the bulk samples and 1 to 2 percent in the fractions smaller than 3.5 micrometers. The long-lived natural radionuclide content of the ash was comparable to that of crustal material; however, relatively large concentrations of short-lived radon daughters were present and polonium-210 content was inversely correlated with particle size. In vitro biological tests showed the ash to be nontoxic to alveolar macrophages, which are an important part of the lungs' natural clearance mechanism. On the basis of a substantial body of data that has shown a correlation between macrophage cytotoxicity and fibrogenicity of minerals, the ash is not predicted to be highly fibrogenic.  相似文献   

Response: space flight: manned versus unmanned     

VAN Allen JA 《Science (New York, N.Y.)》1986,233(4764):610-611

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Initial Analysis of OSTA-1 Ocean Color Experiment Imagery     

Kim HH  Hart WD  VAN DER Piepen H 《Science (New York, N.Y.)》1982,218(4576):1027-1031

Ocean images were obtained at three widely separated locations on the earth as part of NASA's ocean color experiment. Digital computer enhancement and band-ratioing techniques were applied to radiometrically corrected spectral data to emphasize patterns of chlorophyll distribution and, in one case, of bottom topography. The chlorophyll pattern in the Yellow Sea between China and Korea was evident in a scene produced from shuttle orbit 24. The effects of the discharge from the Yangtze and other rivers were also observed. Two scenes from orbits 30 and 32 revealed the movement of patches of plankton in the Gulf of Cádiz. Geometric corrections of these images permitted ocean current velocities in the vicinity to be deduced. The variability in water depth over the Grand Bahama Bank was estimated by using the blue-green channel of the instrument. The very clear water conditions in the area caused bottom-reflected sunlight to produce a sensor signal that was inversely related to the depth of the water.  相似文献   

Use of Trisodium Phosphate in Microscopical Technic     

VAN Cleave HJ  Ross JA 《Science (New York, N.Y.)》1947,106(2748):194

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Safety and tolerability of 3-week and 6-month dosing of Deramaxx^® (Deracoxib) chewable tablets in dogs     

E. S. ROBERTS  K. A. VAN LARE  B. R. MARABLE  & W. F. SALMINEN 《Journal of veterinary pharmacology and therapeutics》2009,32(4):329-337

Although non-steroidal anti-inflammatory drugs (NSAIDs) are effective in reducing pain and inflammation, these agents have adverse effects. Selective inhibitors of COX-2 are an alternative to traditional NSAIDs. Deramaxx^® [Novartis Animal Health US, Inc. (NAH), Greensboro, NC, USA] contains the selective COX-2 inhibitor, deracoxib, and is approved for the relief of pain and inflammation associated with orthopedic surgery and osteoarthritis in dogs. The safety of Deramaxx was evaluated in two target animal safety studies: 40 dogs (four dogs/sex/group) received 0, 4, 6, 8, or 10 mg/kg/day deracoxib once daily for 21 days; and 60 dogs (five dogs/sex/group) received 0, 2, 4, 6, 8, or 10 mg/kg/day deracoxib once daily for 6 months. There was a dose-dependent trend towards increased blood urea nitrogen (BUN) in treated dogs, however mean BUN values remained within the reference range at the labeled doses. In both trials, histopathology revealed focal renal tubular degeneration/regeneration in some dogs receiving ≥6 mg/kg/day deracoxib. Focal renal papillary necrosis was seen in one dog treated with 8 mg/kg/day and in three dogs receiving 10 mg/kg/day deracoxib on the 6-month study. No other parameters of renal function were adversely affected for either study. Results show that Deramaxx is safe and well-tolerated in dogs when administered as directed.  相似文献