微量元素硒治疗肝病138例的探讨

用西维尔(硒酵母片)治疗了肝病138例，对其疗效进行了观察和探讨。结果表明，硒对各种肝炎、肝肿大者疗效显著；对已患肝癌或肝硬化者疗效不明显。     

Ferromagnetically coupled Shastry-Sutherland quantum spin singlets in (CuCl)LaNb₂O₇

A thorough crystal structure determination at very low temperature of (CuCl)LaNb?O?, originally proposed as a spin-1/2 square-lattice antiferromagnet, is reported thanks to the use of single-crystal x-ray diffraction and powder neutron diffraction. State-of-the-art calculations (maximum entropy method) reveal that (CuCl)LaNb?O? is orthorhombic with Pbam symmetry. First-principles calculations demonstrate that the dominant magnetic interactions are antiferromagnetic between fourth nearest neighbors with a Cu-Cl-Cl-Cu exchange path, which lead to the formation of spin singlets. The two strongest interactions between the singlets are ferromagnetic, which makes (CuCl)LaNb?O? the first system of ferromagnetically coupled Shastry-Sutherland quantum spin singlets.     

Crystal structure oftrans-carbonylchlorobis-(tricyclohexylphosphine)iridium(I),trans-Ir(CO)Cl-[P(cyclo-C6H11)3]2, a disordered species

The title compound crystallizes in the centrosymmetric triclinic space group (C ₁ ^l ; No.2) witha=9.9143(10) Å,b=10.2616(11) Å,c=10.7715(10) Å, =113.887(8)°, =109.197(8)°, =90.699(9)°,V=932.78(17) ų andZ=1. A total of 4869 data were collected and merged to a set of 2450 independent reflections; the structure was solved and refined toR=1.42% andwR=1.94%. The molecule lies on a site of symmetry and is disordered, with obvious scrambling of carbonyl and chloride ligands. Resulting bond lengths include Ir–P=2.339(1) Å, Ir–Cl=2.398(4) Å and Ir–CO=1.808(15) Å.     

On the Møller Energy Associated with Black Holes

In this paper, we consider both Einstein's theory of general relativity and the teleparallel gravity (the tetrad theory of gravitation) analogs of the energy-momentum definition of Møller in order to explicitly evaluate the energy distribution (due to matter and fields including gravity) associated with a general black hole model which includes several well-known black holes. To calculate the special cases of energy distribution, here we consider eight different types of black hole models such as anti-de Sitter Cmetric with spherical topology, charged regular black hole, conformal scalar dyon black hole, dyadosphere of a charged black hole, regular black hole, charged topological black hole, charged massless black hole with a scalar field, and the Schwarzschild-de Sitter space-time. Our teleparallel gravitational result is also independent of the teleparallel dimensionless coupling constant, which means that it is valid not only in teleparallel equivalent of general relativity but also in any teleparallel model. This paper also sustains (a) the importance of the energy-momentum definitions in the evaluation of the energy distribution of a given spacetime and (b) the viewpoint of Lessner that the Møller energy-momentum complex is the powerful concept to calculate energy distribution in a given space-time.     

Energy of a Charged Wormhole

The Møller energy(due to matter and fields including gravity) distribution of the traversable Lorentzian wormhole space-time by the scalar field or electric charged is studied in two different approaches of gravity such as general relativity and tele-parallel gravity. The results are found exactly the same in these different approximations. The energy found in tele-parallel gravity is also independent of the tele-parallel dimensionless coupling constant, which means that it is valid in any tele-parallel model. Our results sustains that (a) the importance of the energy-momentum definitions in the evaluation of the energy distribution of a given space-time and (b) the viewpoint of Lassner that the Møller energy-momentum complex is a powerful concept of energy and momentum.     

Applying an alternative mathematics pedagogy for students with weak mathematics: meta-analysis of alternative pedagogies

Student mathematics performance and the need for work-ready graduates to be mathematics-competent is a core issue for many universities. While both student and teacher are responsible for learning outcomes, there is a need to explicitly acknowledge the weak mathematics foundation of many university students. A systematic literature review was undertaken of identified innovations and/or interventions that may lead to improvement in student outcomes for university mathematics-based units of study. The review revealed the importance of understanding the foundations of student performance in higher education mathematics learning, especially in first year. Pre-university mathematics skills were identified as significant in student retention and mathematics success at university, and a specific focus on student pre-university mathematics skill level was found to be more effective in providing help, rather than simply focusing on a particular at-risk group. Diagnostics tools were found to be important in identifying (1) student background and (2) appropriate intervention. The studies highlighted the importance of appropriate and validated interventions in mathematics teaching and learning, and the need to improve the learning model for mathematics-based subjects, communication and technology innovations.     

Validated LC‐MS/MS assay for the quantitative determination of vardenafil in human plasma and its application to a pharmacokinetic study

A sensitive high‐performance liquid chromatography–tandem mass spectrometric (HPLC‐MS/MS) assay has been developed for the quantitative analysis of vardenafil in human plasma. Vardenafil and the internal standard, alprazolam, were extracted from 0.2 mL aliquots of alkalinized plasma by a single solvent extraction into hexane : dichloromethane. Reversed‐phase chromatographic separation was affected by gradient elution with mobile phases consisting of 10 mM ammonium formate pH 7.0 (solvent A) and methanol (100%, solvent B), delivered at a flow rate of 0.4 mL/min. The analytes were detected by using an electrospray ion source on a 4000 QTrap triple quadrupole mass spectrometer operating in positive ionization mode. The mass transitions were m/z 489.3 → 312.2 for vardenafil and m/z 309.2 → 281.0 for alprazolam. The assay was linear over the concentration range of 0.2–100 ng/mL, with correlation coefficients ≥0.995. The intra‐ and inter‐day precision was less than 5.4% in terms of relative standard deviation and the accuracy was within 12.7% in terms of relative error. The lower limit of quantitation was set at 0.2 ng/mL. The high sensitivity and acceptable performance of the assay allowed its application to the analysis of plasma samples obtained following the oral administration of vardenafil to healthy male volunteers in a pharmacokinetic study. Copyright © 2009 John Wiley & Sons, Ltd.     

Synthesis of Pure O,O,S-Trialkyl Phosphorodithioates

Abstract

Esters of phosphorodithioic acid are of importance in pesticide formulations¹ and as oil additives.² The widely used method of preparation is to reflux the alkali metal salt of dialkyl phosphorodithioic acid with an alkyl bromide in alcoholic solution,³ i.e.