نتایج جستجو برای: deuterium depleted water
تعداد نتایج: 580450 فیلتر نتایج به سال:
The deuterium-to-hydrogen ratio (D/H) in water found in the coma of Jupiter family comet (JFC) 67P/ Churyumov–Gerasimenko was reported to be (5.3±0.7)×10, the highest among comets and three times the value for other JFCs with an ocean-like ratio. This discrepancy suggests the diverse origins of JFCs and clouds the issue of the origin of Earth’s oceanic water. Here we demonstrate that Eley–R...
EBAL PROCEDURES are available for determination of deuterium in water by mass spectrometry. In the method of Solomon (1), water and deuterium oxide are reduced with hot zinc, and lative concentrations of deuterium and hydrogen are measured. ber of investigators have utilized this procedure in precise and ive studies (2-5). Other indirect methods were mentioned by burn et at. (6) in a study in w...
Much information on ionic solvation in electrolyte solutions has been inferred from macroscopic thermodynamic and transport properties and from spectroscopy. These ion-water interactions can now be probed directly and unambiguously by neutron diffraction. Such measurements have been done with neodymium trichloride solutions in heavy water that are identical in every respect except the isotopic ...
Deuterium-depleted water (DDW) is a new promising agent in cancer therapy. The efficiency of the method is based on the discovery, that cancer cells are extremely sensitive to depletion of deuterium (D) and might cause necrosis of the tumour. The purpose of this study was to show the efficacy of D-depletion in prostate cancer (PC) patients. In the double blind, four-month-long, randomized Phase...
Hydrogen isotope ratios in lipids derived frommangroves have the potential to be used for paleohydrologic reconstructions and could serve as a much needed tool for establishing past climate variability in the tropics. We assessed the effect of salinity on the apparent fractionation factor, aa, between mangrove derived n-alkanes and their source water for Avicennia marina (gray mangrove) specime...
Deuterium dilution for the measurement of total body water (TBW) has been conducted using varying protocols for equilibration. We measured TBW from deuterium dilution in urine samples in twenty-eight subjects using three protocols: (1) early morning dosage without breakfast, measuring deuterium in a second voiding at 4 h and 6 h; (2) early morning dosage with breakfast with the same measurement...
ISIDORE S. EDELMAN, M.D. TO DATE, deuterium oxide (D20) has been the most satisfactory and accurate tracer substance for body water: its diffusion characteristics have been thoroughly studied, and its reliability as a tracer for body water by the dilution technic has been established.' 2 However, the technical difficulty of deuterium analysis by the falling drop method and the labor and expense...
Pd-catalyzed intramolecular asymmetric carbopalladation of N-aryl acrylamides followed by reduction of C(sp3 )-Pd intermediate using diboron-water as a hydride source afforded enantioenriched 3,3-disubstituted oxindoles in high yields and enantioselectivities. When heavy water was used as a deuterium donor in combination with bis(catecholato)diboron (Cat2 B2 ), deuterium was incorporated into t...
Human cholesterogenesis is measurable as the rate of incorporation of deuterium derived from deuterium oxide (D2O) within the body water pool into plasma or erythrocyte cholesterol pools. Oral D2O equilibrates across body water, thus enabling extracellular sampling of pools (such as urine) to serve as accurate indicators of intracellular deuterium enrichments at the point of synthesis. Required...
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