Mesh, gravity and load effects on finite element simulations of blast loaded reinforced concrete structures

The behavior and design of reinforced concrete blast resistant structures are supported by intensive numerical simulations, and the effects of various parameters on the results is of great interest. Finite element simulations were performed in the nonlinear dynamic domain with modified concrete and steel constitutive models. Ten different cases were implemented, each with different reinforcement details. In addition, each case included both a coarse mesh and a fine mesh to determine the effects of mesh resolution on the numerical simulations. Gravity and loading conditions were altered to investigate their influences on the results. Deformations and stress distributions in both the concrete and steel were examined to determine the composite structural behavior and the extent of predicted damage for the various cases. The observations from these analyses highlighted relationships between the simulation parameters and the corresponding outcome. Conclusions and recommendations are presented that could assist in the development of efficient numerical simulations in this general area.     

Involvement of polyamines in the protection of taurine against the cytotoxicity of hydrazine or carbon tetrachloride in isolated rat hepatocytes

Taurine (2-aminoethanesulfonic acid) is known to protect hepatocyte injury induced by hydrazine or carbon tetrachloride. We investigated whether cellular polyamines are involved in the protective mechanism of taurine in the hepatocyte injury caused by hydrazine or carbon tetrachloride. The agents decreased cellular polyamine concentrations, but the treatment with taurine prevented this decrease. The protection of taurine against hepatic injury was not observed in hepatocytes treated with alpha-difluoromethylornithine (DFMO), an irreversible inhibitor of ornithine decarboxylase which is a key enzyme in polyamine biosynthesis. The protection of taurine was recovered by the addition of polyamines to DFMO-treated hepatocytes. These results suggest that cellular polyamines play an important role in the protection of taurine in hydrazine or carbon tetrachloride-induced hepatocyte injury.     

The repetitive activation of extracellular signal-regulated kinase is required for renal regeneration in rat

In this study, we investigated the activation of p42 extracellular signal-regulated kinase (ERK2) during renal regeneration after HgCl2-induced acute renal failure (ARF) in rat. ERK2 activation was observed at 5 and 29 hr after HgCl2 injection, respectively. The tyrosine phosphorylation of hepatocyte growth factor receptor (c-MET) occurred between 2.5 and 5 hr after the treatment. On the other hand, the phosphorylation of epidermal growth factor receptor (EGFR) was transiently observed at 29 hr after the injection. The peak of ornithine decarboxylase activity as a marker of G1 phase was at 10 hr, and subsequently the labeling index of proliferating cell nuclear antigen as a marker of S phase increased at 53 hr. These results indicate that the repetitive activation of ERK2 related to the phosphorylation of c-MET and EGFR is required for the renal regeneration in HgCl2-induced ARF of rat.     

Magnetic-field-induced non-linear effects of Josephson coupled superconductor Bi2Sr2CaCu2O8+δ

The dc current-voltage (I-V) relation along the c-axis of single crystalline Bi₂Sr₂CaCu₂O_8+δ has been measured in magnetic fields parallel and perpendicular to the c-axis. In zero field a clear and sharp jump with large hysteresis in theI-V curve was observed, indicative of the dc-Josephson effect. In magnetic field below a characteristic fieldB ^*≈0.4 T (at T=0 K) parallel to the c-axis the magnetic field suppresses the hysteresis and reduces the critical currentI _c drastically, whereas aboveB ^* theI-V curve becomes broad and featureless behavior. The characteristic field scaleB ^* can be interpreted as an energy scale of the Josephson coupling between superconducting layers in Bi₂Sr₂CaCu₂O_8+δ and is argued with emphasis on the correlation length of pancake vortices in this system.     

IDR digital modem terminal equipment

This paper describes NEC's latest IDR digital modulator and demodulator equipment, and the IDR digital modem terminal configuration with its associated 1:N redundancy switch-over and monitor and control units, to comply with the current INTELSAT specification IESS-308 (Rev. 4).     

Highly hydrogenated dietary soybean oil modifies the responses to polychlorinated biphenyls in rats

The effects of dietary highly hydrogenated soybean oil (HSO) upon the changes caused by dietary polychlorinated biphenyls (PCBs) were examined in rats. Six groups of rats were fed the following diets for 30 d: a 20% soybean oil-containing diet (control diet), a diet in which a half of soybean oil was substituted with HSO (HSO-A diet), a diet in which cellulose powder was replaced with HSO (HSO-B diet) and these diets supplemented with 100 ppm PCBs (control+PCBs, HSO-A+PCBs and HSO-B+PCBs diets). Hepatic concentration of PCBs and relative liver weight were markedly decreased in rats fed with the HSO-A+PCBs diet compared with those fed with the other diets containing PCBs. Liver lipids and liver cholesterol were considerably decreased with a reciprocal increase in fecal sterol excretion by rats fed the HSO-A+PCBs and the HSO-B+PCBs diets compared with those fed with the control+PCBs diet. The fatty acid composition in hepatic phospholipids showed an independent increase of the saturated fatty acid content induced by dietary HSO and PCBs. Dietary PCBs also caused decreases in the amounts of monounsaturated and n-3 polyunsaturated fatty acids. These results suggest that dietary HSO prevents accumulation of PCBs in the liver and promotes the excretion of lipids stimulated by PCBs, accompanied by a change in fatty acid metabolism.     

Distribution of burst error lengths in Rayleigh fading radio channels

A method for measuring burst errors which occur in v.h.f. or u.h.f. digital land mobile radio channels is described. Then it is noted that the cumulative distribution of burst error lengths in a Rayleigh fading channel is approximately governed by the log-normal distribution.     

Structure-activity relationships among substituted N-benzoyl derivatives of phenylalanine and its analogs in a microbial antitumor prescreen I: Derivatives of o-fluoro-DL-phenylalanine

Twelve derivatives of 0-fluoro-dl-phenylalanine containing fluorine, chlorine, methoxy, and nitro radicals in various positions of the aromatic ring of the benzoyl group were prepared and tested in a Lactobacillus casei system. It was found that most substitutions in the benzoyl phenyl ring resulted in a compound exhibiting greater growth-inhibiting activity than the nonsubstituted benzoyl-o-fluorophenylalanine. The greatest activity was observed in the ortho-substituted fluoro compound and the meta- and para-substituted chloro and nitro compounds. With the methoxy group, the position of substitution appeared unimportant, since all three methoxy isomers exhibited essentially equal inhibition. Nitro substitution in the ortho position had a protective effect in that the product was less active than the unsubstituted benzoyl-o-fluoro-dl-phenylalanine.     

Synthesis of eel-calcitonin and (asu1,7)-eel-calcitonin: contribution of the disulfide bond to the hormonal activity

Eel-calcitonin and its [asu1,7]-analog, deamino-dicarba-analog, were synthesized by the conventional solution method. The natural-type product showed 4300 MRC U/mg in the hypocalcemic potency which was comparable to that of the natural hormone isolated from eel. Hormonal activity of the Asu-analog was also as high as 3400 MRC U/mg.     

Quantitative and easy estimation of a crystal bending effect using low-order CBED patterns

The quantitative measurement of a crystal bending effect is performed using low-order zone-axis convergent beam electron diffraction (CBED) patterns. Although the accuracy of the present method is inferior to that of the method of using split higher order Laue zone lines, this method enables us to estimate the crystal bending effect at a region very close to the interface and to easily judge whether the crystal bending effect results in a tensile bend or a compressive bend. As an application of the present method, the crystal bending effect at a region close to the SiGe/Si interface was measured. It was found that the crystal bending effect is due to a thin-foil relaxation of almost 0.3 degrees at a region that is approximately 10 nm away from the interface.