3,488 research outputs found
Rapid chemical test for the identification of chromium-molybdenum steel
This note describes a simple, rapid, qualitative test which can be applied to solutions of drilling or chips for the identification of chromium-molybdenum steel. The test is based on the orange-red compound which is formed when thiocyanate and inequivalent molybdenum react. This test is much more reliable than the potassium ethylxanthate test which has been recommended for a like purpose. A list of the apparatus and reagents which are required, and a description of the procedure follows
Identification of Novel Methane-, Ethane-, and Propane-Oxidizing Bacteria at Marine Hydrocarbon Seeps by Stable Isotope Probing
Marine hydrocarbon seeps supply oil and gas to microorganisms in sediments and overlying water. We used stable isotope probing (SIP) to identify aerobic bacteria oxidizing gaseous hydrocarbons in surface sediment from the Coal Oil Point seep field located offshore of Santa Barbara, California. After incubating sediment with ^(13)C-labeled methane, ethane, or propane, we confirmed the incorporation of ^(13)C into fatty acids and DNA. Terminal restriction fragment length polymorphism (T-RFLP) analysis and sequencing of the 16S rRNA and particulate methane monooxygenase (pmoA) genes in ^(13)C-DNA revealed groups of microbes not previously thought to contribute to methane, ethane, or propane oxidation. First, ^(13)C methane was primarily assimilated by Gammaproteobacteria species from the family Methylococcaceae, Gammaproteobacteria related to Methylophaga, and Betaproteobacteria from the family Methylophilaceae. Species of the latter two genera have not been previously shown to oxidize methane and may have been cross-feeding on methanol, but species of both genera were heavily labeled after just 3 days. pmoA sequences were affiliated with species of Methylococcaceae, but most were not closely related to cultured methanotrophs. Second, ^(13)C ethane was consumed by members of a novel group of Methylococcaceae. Growth with ethane as the major carbon source has not previously been observed in members of the Methylococcaceae; a highly divergent pmoA-like gene detected in the ^(13)C-labeled DNA may encode an ethane monooxygenase. Third, ^(13)C propane was consumed by members of a group of unclassified Gammaproteobacteria species not previously linked to propane oxidation. This study identifies several bacterial lineages as participants in the oxidation of gaseous hydrocarbons in marine seeps and supports the idea of an alternate function for some pmoA-like genes
The effect of garlic supplementation on flow-mediated dilation after acute maximal exercise
Antioxidative compounds found in garlic may overcome exercise-induced oxidative stress (OS) and attenuate any associated decrease in endothelial function, perhaps leading to performance improvements in high intensity exercise. The purpose of the current study was to investigate whether or not a single dose garlic supplement induced positive changes to flow-mediated dilation (FMD), a measure of nitric oxide mediated endothelial function, in young, trained adults before and after maximal exercise. Maximal oxygen consumption (VO2max) was measured to determine if any changes in FMD were associated with performance improvements. A total of 11 trained participants (aged 20.64 ± 2.25 yrs) were included in the analysis. Participants were randomized to receive either the placebo, which contained 900 mg of all-purpose flour, or 900 mg of powdered garlic three hours prior to data collection. Flow-mediated dilation measurements were taken following 20 min rest (PRE), immediately following a treadmill VO2max test (IPE), and 1-hour post-exercise (1HR). All FMD measurements were taken in the right arm. This protocol was repeated with either the placebo or garlic supplement (depending upon randomization) at least two weeks after the initial test date. Although relative (garlic = 61.20 ± 6.44 ml•kg•min-1, placebo = 59.09 ± 6.96 ml•kg•min-1, p = 0.021) and absolute (garlic = 4.57 ± 0.61 L•min-1, placebo = 4.44 ± 0.52 L•min-1, p = 0.045) VO2max were higher in the garlic trial, no significant differences were found between PRE, IPE, or 1HR- FMD (PRE garlic: 0.068 mm ± 0.032 mm, PRE placebo: 0.071 mm ± 0.051 mm, IPE garlic: 0.091 mm ± 0.119 mm, IPE placebo: 0.071 mm ± 0.084 mm, 1HR garlic: 0.084 mm ± 0.097 mm, 1HR placebo: 0.108 mm ± 0.097 mm; p = 0.479). In addition, there were no significant differences found between PRE, IPE, and 1HR peak lumen diameter measurements (p = 0.524), or between PRE, IPE, and 1HR time to peak diameter measurements (p = 0.641). The results of the current study suggest that a single-dose garlic supplement improves VO2max in young, healthy subjects but that the improvements are not related to alterations in NO bioavailability as measured by FMD
Dynamics Explorer twin spacecraft under evaluation tests
The Dynamics Explorer A and B satellites designed to explore the interactive processes occuring between the magnetosphere and Earth's ionosphere, upper atmosphere, and plasmasphere are described. Effects of these interactions, satellite orbits, data collecting antennas, solar power systems, axes, configurations, and Earth based command, control and data display systems are mentioned
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