Microencapsulation of astiban acid for the treatment ofSchistosomiasis mansoni

Schistosomiasis is among the top five diseases in the world in terms of morbidity, affecting perhaps 200 million people in tropical and subtropical countries. Antischistosomal drugs are toxic and rapidly metabolized. Hence, they must be given in a number of spaced doses. In spite of this there are severe side effects leading to poor patient compliance. This is an ideal situation for the application of sustained drug release to avoid the toxic peak concentration of drug. This study was carried out using Astiban acid, an antimonial drug that is effective againstS. mansoni. Unfortunately, the drug is sufficiently soluble that 50 mg will dissolve in 100 mL water in less than a minute. To permit sustained release of intramuscularly injected drug, microcapsules of astiban acid in poly(d,l-lactic acid) were formed by coacervation. Release studies show that an appreciable fraction of the drug is available at the surface for rapid solution. After this surface drug dissolves, the remaining drug is released slowly with half-times of many hours. After the initial burst, the release of drug follows Higuchi’s equation up to approximately 80% release, with exponentially decreasing release rates thereafter.     

Protonic and Oxygen Conduction of Perovskites ATi0.95M0.05O3 - α (A = Ca,Sr, Ba; M = Mg,Sc) in Humid Air

Measurements of the total conduction (450-1030°C) and transport numbers for ions and protons (450-850°C) of titanates ATi_0.95M_0.05O_{3 -} (A = Ca, Sr, Ba; M = Mg, Sc) in humid air are performed. Partial conductions (ionic, protonic, oxygen, hole) and their effective energies of activation are determined. The results are discussed within a model of separate transport of proton and oxygen ion.     

An electron diffraction study of the molecular structure of gaseous allyl silane

The molecular structure of allyl silane has been studied by gas-phase electron diffraction. The experimental radial distribution curve has only four prominent peaks, resulting in serious resolution problems in the structure determination. A single conformer whose dimensions resemble those of related molecules fits the diffraction data. The torsion angle φ_siccc is102 ± 1°, measured from the conformation having Si-C and CC eclipsed.     

幼儿园与散居儿童微量元素差异的研究

测定了２８７例１－８岁的幼儿园儿童及散居儿童头发中Ｚｎ，Ｆｅ，Ｃｕ，Ｃａ，Ｍｎ和Ｐｂ的含量，并研究了两类儿童头发中上述元素含量的差异。结果表明，两类獐各元素间的相关性相似，各元素含量的平均值与其中位数相似，但散居儿童与幼儿园儿童相比，各元素含量的波动范围较大，有益元素铁和钙和平均值较低，且低于正常值的比例较高，而有害元素２铅依度平均则较高，超过允许值的比例也高，上述三种元素具有非常显著的差异。     

Substitution Coordination Approach for Selective Determination of Complex: Pontachrome Violet SW/Fe(III)/Cu(II) System

The Substitution Coordination for Selective Determination (SCSD) was proposed by studying the complexations of pontachrome violet SW (PCV) with Fe(III) and Cu(II) at pH 5.5. The up dated approach to the de termination of binding constants of a complex was established by the spectral correction technique (SCT). The substitution complexation Cu(II) + Fe(PCV) → Cu(PCV) + Fe(III) has been applied to the direct selective determination of copper traces by the SCT with a high sensitivity.     

SCF MO CI perturbation calculations of inner shell and valence shell vertical ionization potentials

A CI method for calculating inner and valence shell vertical ionization potentials is presented. It is based on ab initio SCF MO calculations for the neutral closedshell ground state followed by CI perturbation calculations for the ground and ion states including all spin and symmetry adapted singly and doubly excited configurations with respect to the main configurations of the state of interest. The state energy is computed by performing a CI calculation for a set of selected configurations, and then adding the contributions of the remaining configurations as estimated by second order Brillouin-Wigner perturbation theory. The use of the same set of MO's for all states together with the CI perturbation method makes the method rather rapid. The numerical results are, in spite of the limited Gaussian basis sets used, in good agreement with experiment.     

Semiempirical molecular orbital studies on the electronic structure of molecules in excited states: The INDO/2-VN— 1 potential model: Part I.

The performance of the V_N—1 potential model at the INDO/2 level of approximation in the calculation of transition energy, singlet—triplet splitting, change in molecular structure, inversion barrier and electron-density distribution in the excited electronic states of a few simple carbonyls is analysed. The method turns out to be reasonably successful in many ways.     

流动注射-氢化物发生原子吸收光谱法测定香烟接装纸中的痕量砷

将流动注射-氢化物发生和原子吸收光谱法有机的结合起来,探讨了流动注射-氢化物发生-原子吸收光谱法测定香烟接装纸中砷的最佳条件。样品经消解后,加入还原剂,使五价砷还原为三价,在盐酸介质中和硼氢化钾反应生成砷化氢,进入电热石英管原子化测定。检测结果相对标准偏差小于5%,加标回收率为96.7%~104%,方法检出限为0.18μg/L。     

Tetracyanonickelate compounds as sorptive materials and the substitution of their H2O content by D2O

The compounds NiNi(CN)₄·3,5H₂O and Ni(NH₃)₂Ni(CN)₄·H₂O have been studied to examine the possibility of substituting their H₂O or NH₃ content by D₂O. Contact with D₂O was performed after heating the compounds to several temperatures. Depending on the degree of decomposition of the original compounds different ranges of substitution were possible. In such manner the compounds NiNi(CN)₄·3,5D₂O, NiNi(CN)₄·5D₂O, Ni(NH₃)₂Ni(CN)₄·D₂O, and Ni(D₂O)₂Ni(CN)₄·D₂O were prepared and thermally they were less stable than the original ones. The substitution by D₂O is in agreement with the sorptive properties of the original tetracyanonickelate against different organic compounds using GC, since these could substitute the guest component and sometimes also the ligands during their decomposition.     

A pyrolytic carbon film electrode for voltammetry-III Application to anodic-stripping voltammetry

The potential applicability of a pyrolytic carbon film electrode in the differential-pulse anodic-stripping voltammetric determination of cadmium and lead in sea-water is demonstrated. The performance at the 10⁻¹⁰M level is compared with that of a satisfactory glassy-carbon electrode. The two types of electrode display comparable behaviour in anodic-stripping voltammetry, but the pyrolytic carbon film electrode needs less pretreatment.