368 research outputs found

    America\u27s Maritime Boundary with the Soviet Union

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    During last year’s Washington Summit meetings between President Bush and Soviet President Gorbachev, a historic agreement was signed by which, for the first time, the United States and the Soviet Union registered their mutual accord on a maritime boundary. 1 This new agreement was signed on 1 June 1990 by Secretary of State Baker and Soviet Foreign Minister Shevardnadze, and both signatories have been fully applying its provisions since 15June 1990

    America\u27s Maritime Boundary with the Soviet Union

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    During last year’s Washington Summit meetings between President Bush and Soviet President Gorbachev, a historic agreement was signed by which, for the first time, the United States and the Soviet Union registered their mutual accord on a maritime boundary. 1 This new agreement was signed on 1 June 1990 by Secretary of State Baker and Soviet Foreign Minister Shevardnadze, and both signatories have been fully applying its provisions since 15June 1990

    Military-to-Military Arrangements for the Prevention of U.S.-Russian Conflict

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    An important aspect of conflict prevention, avoidance, and resolution in the international security area is illustrated by several military-to-military arrangements originally worked out between the United States and the Soviet Union (and now in force with Russia) to deal with disputes of an operational nature—those which, if not resolved, might lead to actual conflict

    Regional Enforcement Action under the United Nations Charter and Constraints upon States Not Members

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    Book Review

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    Reaction Energetics and ¹³C Fractionation of Alanine Transamination in the Aqueous and Gas Phases

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    The alanine transaminase (ALT) enzyme catalyzes the transfer of an amino group from alanine to α-ketoglutarate to produce pyruvate and glutamate. Isotope fractionation factors (IFFs) for the reaction ⁺H₃NCH(CH₃)COO⁻ + ⁻OOCCH₂CH₂C(O)COO⁻ ↔ CH₃C(O)COO⁻ + ⁻H₃NCH(CH₂CH₂COO⁻)COO⁻ (zwitterionic neutral alanine + doubly deprotonated α-ketoglutarate ↔ pyruvate + zwitterionic glutamate anion) were calculated from the partition functions of explicitly and implicitly solvated molecules at 298 K. Calculations were done for alanine (non-charge separated, zwitterion, deprotonated,), pyruvic acid (neutral, deprotonated), glutamic acid (non-charge separated, zwitterion, deprotonated, doubly deprotonated), and α-ketoglutaric acid (neutral, deprotonated, doubly deprotonated). The computational results, calculated from gas phase and aqueous optimized clusters with explicit H₂O molecules at the MP₂/aug-cc-pVDZ and MP₂/aug-cc-pVDZ/COSMO levels, respectively, predict that substitution of ¹³C at the C2 position of alanine and pyruvic acid and their various forms leads to the C2 position of pyruvic acid/pyruvate being enriched in ¹³C/¹²C ratio by 9 ‰. Simpler approaches that estimate the IFFs based solely on changes in the zero-point energies (ZPEs) are consistent with the higher-level model. ZPE-based IFFs calculated for simple analogues formaldehyde and methylamine (analogous to the C₂ positions of pyruvate and alanine, respectively) predict a ¹³C enrichment in formaldehyde of 7 to 8 ‰ at the MP₂/aug-cc-pVDZ and aug-cc-pVTZ levels. A simple predictive model using canonical functional group frequencies and reduced masses for ¹³C exchange between R₂C=O and R₂CH-NH₂ predicted enrichment in R₂C=O that is too large by a factor of two, but is qualitatively accurate compared with the more sophisticated models. Our models are all in agreement with the expectation that pyruvate and formaldehyde will be preferentially enriched in ¹³C due to the strength of their >C=O bond relative to that of the ≡C-NH₂ in alanine and methylamine. ¹³C/¹²C substitution is also modeled at the methyl and carboxylic acid sites of alanine and pyruvic acid, respectively

    One and Two Dimensional Pulsed Electron Paramagnetic Resonance Studies of in vivo Vanadyl Coordination in Rat Kidney

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    The biological fate of a chelated vanadium source is investigated by/n vivo spectroscopic methods to elucidate the chemical form in which the metal ion is accumulated. A pulsed electron paramagnetic resonance study of vanadyl ions in kidney tissue, taken from rats previously treated with bis(ethylmaltolato)oxovanadium(IV) (BEOV) in drinking water, is presented. A combined approach using stimulated echo (3-pulse) electron spin echo envelope modulation (ESEEM) and the two dimensional 4-pulse hyperfine sublevel correlation (HYSCORE) spectroscopies has shown that at least some of the VO2+ ions are involved in the coordination with nitrogen-containing ligands. From the experimental spectra, a 4N hyperfine coupling constant of 4.9 MHz and a quadrupole coupling constant of 0.6 + 0.04 MHz were determined, consistent with amine coordination of the vanadyl ions. Study of VO-histidine model complexes allowed for a determination of the percentage of nitrogen-coordinated VO2+ ions in the tissue sample that is found nitrogen-coordinated. By taking into account the bidentate nature of histidine coordination to VO2+ ions, a more accurate determination of this value is reported. The biological fate of chelated versus free (i.e. salts) vanadyl ion sources has been deduced by comparison to earlier reports. In contrast to its superior pharmacological efficacy over VOSO4, BEOV shares a remarkably similar biological fate after uptake into kidney tissue

    Understanding Primary Care Physician Perspectives On the Diagnosis and Management of Non-Alcoholic Fatty Liver Disease: a Qualitative Study

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    Primary care physicians (PCPs) are well suited to manage patients with non-alcoholic fatty liver disease (NAFLD), but the limited, existing research suggests inadequate knowledge about the natural history, diagnostic methods, and management of NAFLD. The purpose of this qualitative study is to further understand the knowledge and practices for the diagnosis and management of NAFLD among PCPs. We conducted in-depth interviews with PCPs in the Greater Houston area, addressing current clinical practices used for diagnosing and managing NAFLD, as well as the perceptions of the PCPs regarding the burden of NAFLD on patients. We recorded interviews, transcribed them, coded transcripts, and identified patterns and themes. The interviewed PCPs (n = 16) were from internal or family medicine, with a range of experience (1.5-30 years). We found variations in NAFLD diagnosis and management across practices and by insurance status. Patients with abnormal liver imaging who had insurance or were within a safety-net healthcare system were referred by PCPs to specialists. Uninsured patients with persistently elevated liver enzymes received lifestyle recommendations from PCPs without confirmatory imaging or specialist referral. The role of PCPs in NAFLD management varied, with some helping patients set dietary and physical activity goals while others provided only general recommendations and/or referred patients to a dietitian. The diagnosis and management of NAFLD vary widely among PCPs and may be impacted by patients\u27 insurance status and clinic-specific practices. The increasing burden of NAFLD in the U.S. medical system highlights the need for more PCPs involvement in managing NAFLD
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