Laboratory and field measurements of dry deposition of sulfur dioxide onto Chinese loess surfaces

Laboratory and field measurements were conducted to examine dry deposition of SO2 onto Chinese loess surfaces using native soil sampled in the loess plateau, China. The field tests were employed in Beijing and Lanzhou, China, by directly measuring the dry deposition of SO2 on soil, which uses soil put on a collector as an SO2 passive sampling medium. In the laboratory, a high rate of uptake to SO2 deposition for Chinese soil surfaces due to the highly alkalinity was found. The uptake of SO2 deposition was dependent on the pH soil and relative humidity. Furthermore, we evaluated some factors that affect the measurement precision: response of SO2 uptake, repeatability, recovery factor, and variability associated with the weight and the surface coverage on the collectors. As a result, it was shown that the measurement precision was primarily related to the ratio of the SO2 deposition amount relative to the sulfur content of the original soil. This result was consistent with the field observations. The laboratory and field results indicated an excellent agreement on the SO2 uptake inherent in the results from the soil surfaces in different regions.     

Non-protein energy overloading induces bacterial translocation during total parenteral nutrition in newborn rabbits

From a Maltese sample of the marine sponge Agelas oroides, five compounds: oroidin (1), 2-cyano-4,5-dibromopyrrole (2), 4,5-dibromopyrrole-2-carboxylic acid (3), 4,5-dibromopyrrole-2-carboxylic acid methyl ester (4), and 4 alpha-methyl-5 alpha-cholest-8-en-3 beta-ol (5) have been isolated. For compounds 1-5, completely assigned 1H- and 13C-NMR data are reported for the first time. For 2 a single crystal X-ray crystallographic analysis proved its structure unambiguously. The X-ray analysis of 2 indicated it to crystallise in an unexpected polar space group. Biological activity assessment of all isolates indicate 5 to have moderate antiplasmodial activity, as well as being cytotoxic, and 2 to be moderately cytotoxic towards several cancer cell lines.     

The generalized boundary element approach to Burgers' equation

The generalized boundary element method is presented for the numerical solution of Burgers' equation. The new method is based on the set of boundary integral equations derived for each subdomain by using the fundamental solution for the linearized differential operator of the equation. The resulting system of quasi-non-linear equations is solved implicitly with use of a simple iterative procedure. The adaptability and the accuracy of the proposed method are demonstrated by three examples and a comparison of the numerical results with the exact solution or other existing solutions is shown for the first example.     

Morphologic changes in hepatocyte nuclei of streptozotocin (SZ)-induced diabetic mice

Morphological examinations were carried out on hepatocyte nuclei of streptozotocin (SZ)-induced diabetic mice. The area of hepatocyte nuclei in diabetic mice was about two times larger than that in control mice, and the incidence of hepatocytes with intranuclear inclusions was 3.4 +/- 0.2% in diabetic mice and 0% in control mice, respectively. Although the incidence of binuclear hepatocytes was not significantly different between diabetic (14.5 +/- 4.6%) and control mice (16.4 +/- 4.4%), the morphology of the nuclei of binuclear hepatocytes was apparently different between diabetic and control mice. Namely, the nuclei of binuclear hepatocytes of control mice were round and identical in ultrastructural appearance, and they did not differ from those of mononuclear diploid hepatocytes. On the other hand, the nuclei of binuclear hepatocytes of diabetic mice were not identical in distribution pattern of chromatin granules, and they frequently varied in size and showed irregular contours.     

Effect of GaAs surface pretreatment on electrical properties of MBE-ZnSe/GaAs substrate interfaces

Interface properties of MBE-grown ZnSe/GaAs substrate systems formed on variously pretreated GaAs surfaces, which include standard chemically etched (5H₂SO₄:1H₂O₂: 1H₂O), (NH₄)₂S_x-, NH₄I-, and HF-pretreated surfaces, are investigated by capacitance-voltage (C-V) and deep level transient spectroscopy (DLTS) measurements. A HF-pretreated and annealed ZnSe/p-GaAs sample showed marked reduction of interface state density, N_ss, with N_ss,_min below 4 x 10¹¹cm^-2 eV^-1 near E_c- E_FS= 1.0 eV. The value is about one order of magnitude smaller than that of the standard chemically etched interface, and comparable to (NH₄)₂S_x- pretreated interface. Nevertheless, C-V characteristics of ZnSe/nGaAs samples, which were measured for the first time, indicate that interface Fermi level, E_FS, is not completely unpinned due to the interface states located above the midgap. A consistent result was obtained by DLTS method in determining E_FS position. The influence of N_ss distribution on vertical current conduction is also analyzed. It is found that U-shaped interface states with N_ss(E) > 1 x 10¹³ cm^-2 eV^-1 above the midgap may cause an excess voltage drop larger than a few volts at the interface.     

Ti-Containing Silsesquioxane Gels with Tunable Porosity: Preparation and Catalytic Activity for the Epoxidation of Cyclooctene by Aqueous Hydrogen Peroxide

Novel Ti-containing silsesquioxane gel catalysts were prepared by the hydrosilylative condensation of Ti-containing silsesquioxanes together with cubic silsesquioxanes and spherosilicates. The porosity of gels was controlled by changing the composition and the mixing order of the starting materials. Both porous and nonporous gels were found to act as excellent heterogeneous catalysts towards the selective epoxidation of cyclooctene by the use of aqueous hydrogen peroxide as an oxidant.     

Estimation of compound classes in coal hydrogenation liquids by thin-layer chromatography

Compound classes in coal liquids were investigated by thin-layer chromatography coupled with a flame ionization detector (t.l.c.-f.i.d.). Individual t.l.c. peaks for coal liquids were identified as paraffins, aromatics, polar compounds and more strongly polar compounds or asphaltenes in order of increasing R_f values by comparison with specific compounds separated previously by conventional liquid chromatography. Concentrations of compound classes for a series of samples obtained by varying the hydrogenation time were estimated and good agreement was found with the results obtained by the USBM-API 60 liquid chromatography procedure. By using the t.l.c.-f.i.d. method, the relation of distribution of compound classes to the reaction conditions of coal hydrogenation could be derived quantitatively with relative ease.     

Elastic basket switching

This paper proposes a new integrated switching system, ‘elastic basket switching’, for broadband and multimedia communications, including voice and high-speed data. In elastic basket switching (EBS), it is possible flexibly and efficiently to handle multimedia information by adaptively assigning communication resources according to communication requests and bandwidth of switched information. For continuous information, such as voice, EBS functions just as a circuit switching system, and for burst data it achieves high-efficiency bandwidth usage equivalent to a packet switching system by demand-assign type time-slot assignment. The detail of EBS and its application to a departmental system-orientated PBX are described. The traffic handling capability and details of the hardware structure are presented. The experimental system, including use of LSIs in the main parts of EBS is also described.