Hydrogenation of nitro compounds with supported platinum catalyst in supercritical carbon dioxide

Hydrogenation of a series of substituted nitro compounds such as 2-,3-,4-nitroanisole, 2-,3-,4-nitrotoluene, 2,4-dinitrobenzene and 2,4-dinitrotoluene has been studied in supercritical carbon dioxide, scCO₂ (two phases), and ethanol (three phases) with a 5 wt.% carbon supported platinum catalyst. The solubility of these compounds in scCO₂ has also been examined in the presence and absence of hydrogen. The solubility of those nitro compounds increases with increasing CO₂ pressure but decreases with the presence of hydrogen. The solubility is in the order of nitrotoluene > nitroanisole > dinitrotoluene, dinitrobenzene. Although the total conversion obtained with hydrogenation in scCO₂ is similar to that in ethanol, the selectivity to amino products is higher in the former reaction medium, indicating that scCO₂ is an ideal medium for the production of amino compounds with hydrogenation of nitro substrates using conventional supported metal catalysts.     

Phorbol ester stimulates PAF synthesisvia the activation of protein kinase C in rat leukocytes

When rat pleural mononuclear leukocytes were stimulated with 1 μM phorbol myristate acetate (PMA), platelet-activating factor (PAF)-like activity was detected in the supernatant and the cellular fractions of the incubation mixture, as measured by rabbit platelet aggregation. C₁₆PAF activity peaked at 30 min in both fractions. Acetyltransferase activity in the microsomal fraction of the stimulated cells also increased rapidly and showed a peak at 10 min. A protein kinase C inhibitor, staurosporine, and an inhibitor of phospholipase A₂,p-bromophenacylbromide, inhibited stimulated PAF formation in both fractions. Staurosporine also inhibited PMA induced acetyltransferase activity. The data suggest that PMA stimulates PAF synthesis by the remodeling pathway in rat pleural cells through activation of both phospholipase A₂ and acetyltransferase, and that the acetyltransferase, in turn, may be activated through activation of protein kinase C. Based on a paper presented at the Third International Conference on Platelet-Activating Factor and Structurally Related Alkyl Ether Lipids, Tokyo, Japan, May 1989.     

Relationship between pulse sequences and signal intensity of joint fluid in the gradient-echo MR imaging

Platelet-activating factor (PAF) is a proinflammatory phospholipid mediator implicated in necrotizing enterocolitis. Regulation of PAF-acetylhydrolase (AH), the enzyme degrading PAF, is poorly understood. In this study we found that administration of a dose of PAF (1.5 microg/kg, i.v.), which does not cause gross intestinal injury, increased plasma and intestinal PAF-AH in the rat. Cycloheximide (CHX, 5 mg/kg, i.v.) reduced the activity of plasma (but not intestinal tissue) AH in control, as well as in PAF-injected rats, and aggravated systemic inflammation and tissue injury in the latter. The intestinal necrosis induced by PAF and CHX was ameliorated by posttreatment with WEB2170 (a PAF antagonist), indicating a role of endogenous PAF in mediating injury. Both WEB2170 and anti-TNF antibody reduced PAF-induced AH activity in intestinal tissue, but not in the plasma. Allopurinol largely prevented the injury induced by PAF and CHX, but had no effect on the up-regulation of AH. We conclude: 1) de novo protein synthesis is required to maintain physiologic AH level in the plasma; 2) PAF up-regulates plasma and intestinal AH activity; 3) CHX enhances the injurious effect of PAF; 4) endogenous PAF and TNF also play a role in the up-regulation of intestinal AH; the former probably mediating the intestinal injury by PAF; and 5) reactive oxygen species may mediate the injurious effect of PAF plus CHX, but do not contribute to the regulation of AH by PAF.     

Effect of impurity on dissolution behavior of simulated molybdenum cermet fuels

The effects of impurity Zr on dissolution behavior into nitric acid of sintered Mo pellets were investigated using simulated fuels to accumulate basic data and knowledge concerning the matrix of Mo-cermet fuels. Mo pellets containing 1– 10 mol% Zr were prepared by conventional powder metallurgical route. After characterization tests using optical microscopy (OM), X-ray diffraction and secondary electron microscopy-energy dispersive X-ray spectrometry (EDX), the sintered pellets were subjected to dissolution tests by nitric acid. The apparent dissolution rate of Mo pellets containing impurity Zr was found to be followed by the first-order chemical reaction form, which is generally known as a simple chemical reaction. The rate of dissolution of sintered Mo-cermet fuels by nitric acid was found to decrease with the increase of the amount of impurity Zr.     

Rapid erasing of wettability patterns based on TiO2-PDMS composite films

TiO₂-polydimethylsiloxane (TiO₂-PDMS) composite films are prepared using the sol–gel method from a Ti(OBu)₄–benzoylacetone solution containing PDMS. The prepared films are cured by irradiation with ultraviolet (UV) light. Structural changes in the films after UV irradiation are confirmed by UV–vis absorption experiments, which show that an absorption band characteristic of the benzoylacetonate chelate rings disappears. This finding is ascribed to structural changes associated with the dissociation of the chelate rings. The IR spectra of the thin films exhibit a broad absorption band after UV irradiation, indicating that a Ti–O–Ti network forms in the thin film. Contact angles are measured for the TiO₂-PDMS thin films, showing wettability conversion from hydrophobic to superhydrophilic states by irradiation with oxygen plasma for 1 s. This phenomenon is explained by XPS experiments which reveal that the number of carbon atoms decreases, whereas the number of oxygen atoms increases on the surface of the TiO₂-PDMS composite films. Finally, hydrophobic–superhydrophilic patterns are fabricated based on a patterned TiO₂-PDMS composite film. The film displays a rapid change to superhydrophilicity over the whole film surface upon plasma irradiation for 1 s, which means that the wettability patterns are rapidly erasable.     

Origin of electron mobility enhancement in (1 1 1)-oriented InGaAs channel metal-insulator-semiconductor field-effect-transistors

Electrical and physical characteristics of the Al₂O₃/InGaAs interfaces with (1 1 1)A and (1 0 0) orientations were investigated in an attempt to understand the origin of electron mobility enhancement in the (1 1 1)A-channel metal-insulator-semiconductor field-effect-transistor. The (1 1 1)A interface has less As atoms of high oxidation states as probed by X-ray photoelectron spectroscopy. The electrical measurements showed that energy distribution of the interface traps for the (1 1 1)A interface is shifted toward the conduction band as compared to that for the (1 0 0) interface. Laterally-compressed cross-section transmission electron microscopy images showed that the characteristic lengths of the interface roughness are different between the (1 1 1)A and (1 0 0) interfaces. The contributions of the Coulomb and roughness scattering mechanisms are discussed based on the experimental results.     

Learning of symbiotic phenomena between agents by using neural networks

Recently, numerous attempts have been made by researchers to understand the essence of complex phenomena (complex systems). In this paper, we consider biological systems in nature as being among the most complex systems. The purpose of this paper is to propose a method of realizing symbiotic phenomena such as mutual benefit, competition, and exploitation more generally than the Lotka–Volterra equation by using neural networks. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 140(1): 77–88, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.1172 Copyright © 2002 Scripta Technica     

Cutting plane methods for Lagrangian relaxation‐based unit commitment algorithm

In this paper, we study cutting plane methods for a Lagrangian relaxation‐based unit commitment algorithm. In the algorithm, nondifferentiable optimization methods can be applied to optimize the dual function, and a subgradient method which needs parameter tuning and has some drawbacks such as computational inefficiency and oscillating behavior is commonly used. The cutting plane method and the central cutting plane method are applied to the algorithm and implemented using reoptimization techniques. A numerical example shows that both methods are accelerated by the reoptimization techniques and have good convergence without parameter tuning. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(3): 17–29, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10066     

Subtype-specific differences in subcellular localization and chlorethylclonidine inactivation of alpha1-adrenoceptors

Chlorethylclonidine (CEC) inactivation has been used as one criterion to subclassify the alpha1-adrenoceptors (AR); however, the extent of CEC inactivation can vary depending on the CEC treatment. By constructing the FLAG-tagged (N-terminus) and green fluorescent protein (GFP)-fused (C-terminus) alpha1-ARs, we have determined the relationship between CEC sensitivity and the cellular localization of alpha1-AR subtypes using COS-7 cells. In GFP-expressing cells, flow cytometry analysis with anti-FLAG N-terminus antibody detected strong fluorescent signals in most of alpha1B-AR-expressing cells, but low signals in alpha1A-AR-expressing cells. Further examination with confocal microscopy showed that fluorescent signals densely localized intra-cellularly in alpha1A-AR-expressing cells, while most of alpha1B-AR localized on the cell surface. Furthermore, radioligand binding studies with [125I]HEAT showed that CEC (10 microM) treatment of intact cells inactivated approximately 30-40% of alpha1A-AR and >90% of alpha1B-AR, while the CEC treatment of membrane preparations resulted in >80% decrease in the alpha1A-AR density and >90% of alpha1B-AR density, respectively. The results showed that the hydrophilic alkylating agent CEC inactivated only alpha1-AR on the cell surface irrespective of its subtype, and that the subtype-specific sorting is a major determinant for CEC inactivation of alpha1-AR. Subtype-specific cellular localization suggests a new class of functional properties that may explain the signal and functional diversity of homologous alpha1-AR (as well as other G protein-coupled receptors) subtypes.