潜艇水动力尾迹与热尾迹耦合作用的数值模拟

采用FLUENT中的VOF(Volume of Fluid Model)模型,对潜艇在海水有无温度梯度、有无螺旋桨转动和排放冷却水的情况下进行数值模拟,得到了潜艇在不同情况下冷却水的浮升规律,并分析了海面和其它截面的温度分布.计算结果表明:在温度均匀的海水中,潜艇静止悬浮比运动时热尾流浮升效果明显,且运动时螺旋桨的转动可加快热尾流的浮升;温度分层海水中,螺旋桨的转动作用可以把海水下层的冷水搅动翻滚至上层从而加剧了海面冷尾迹的形成.     

平板表面温度工程建模研究

为在红外动态战场仿真中实现目标表面温度场的快速计算,需建立平板表面温度工程计算模型.综合考虑外部环境因素及目标内部因素,并利用数学推导及取值分析,获得平板表面温度与外在及内在因素的理论简化表达式.通过控制变量法分析各主要因素对平板表面温度变化速率的影响,并对其进行数学拟合,进而建立了平板表面温度的工程模型.通过与实测数据及商用软件模拟数据的对比,校验了该工程模型的可靠性.结果表明,该工程模型具有快速计算但不失准确性的特点,对目标表面温度场的实时计算具有重要工程应用价值.     

乳酸链球菌素抑菌机理及在食品保鲜中的研究进展

乳酸链球菌素（Nisin）是由乳酸乳球菌乳酸亚种的某些菌株代谢过程中合成的一种天然生物防腐剂,具有良好的抑菌性,可以有效地抑制革兰氏阳性菌（金黄色葡萄球菌、枯草芽孢杆菌、单增李斯特菌、小球菌等）,尤其是细菌芽孢的生长。且因为摄入后可快速被人体中的蛋白酶消化分解为各种氨基酸不会对人体产生毒害作用,因此被广泛的用于食品保鲜领域。本文主要综述了乳酸链球菌素的抑菌机理及其近10年来在食品保鲜领域中的应用,其中着重讨论了在果蔬保鲜中的应用,最后分析了乳酸链球菌素未来的发展方向,以期为乳酸链球菌素在食品保鲜中的进一步研究和应用提供理论参考。     

Completely Chemically Synthesized Long DNA Can be Transcribed in Human Cells

Chemical ligation reaction of DNA is useful for the construction of long functional DNA using oligonucleotide fragments that are prepared by solid phase chemical synthesis. However, the unnatural linkage structure formed by the ligation reaction generally impairs the biological function of the resulting ligated DNA. We achieved the complete chemical synthesis of 78 and 258 bp synthetic DNAs via multiple chemical ligation reactions with phosphorothioate and haloacyl-modified DNA fragments. The latter synthetic DNA, coding shRNA for luciferase genes with a designed truncated SV promoter sequence, successfully induced the expected gene silencing effect in HeLa cells.     

Blood–Nerve Barrier (BNB) Pathology in Diabetic Peripheral Neuropathy and In Vitro Human BNB Model

In diabetic peripheral neuropathy (DPN), metabolic disorder by hyperglycemia progresses in peripheral nerves. In addition to the direct damage to peripheral neural axons, the homeostatic mechanism of peripheral nerves is disrupted by dysfunction of the blood–nerve barrier (BNB) and Schwann cells. The disruption of the BNB, which is a crucial factor in DPN development and exacerbation, causes axonal degeneration via various pathways. Although many reports revealed that hyperglycemia and other important factors, such as dyslipidemia-induced dysfunction of Schwann cells, contributed to DPN, the molecular mechanisms underlying BNB disruption have not been sufficiently elucidated, mainly because of the lack of in vitro studies owing to difficulties in establishing human cell lines from vascular endothelial cells and pericytes that form the BNB. We have developed, for the first time, temperature-sensitive immortalized cell lines of vascular endothelial cells and pericytes originating from the BNB of human sciatic nerves, and we have elucidated the disruption to the BNB mainly in response to advanced glycation end products in DPN. Recently, we succeeded in developing an in vitro BNB model to reflect the anatomical characteristics of the BNB using cell sheet engineering, and we established immortalized cell lines originating from the human BNB. In this article, we review the pathologic evidence of the pathology of DPN in terms of BNB disruption, and we introduce the current in vitro BNB models.     

Purification of metallurgical silicon up to solar grade

A new production process of solar-grade silicon (SOG-Si) for small demand which is made from metallurgical-grade silicon (MG-Si) is proposed here, based on the findings of silicon refining stage in NEDO (New Energy and Industrial Technology Development Organization) Direct Reduction Process. SOG-Si trially produced was made into a multicrystalline cell through NEDO Project and the conversion efficiency was max. 10.9%.     

Interaction between opiate subtypes and serotonin in suppressing noxiously evoked activity of WDR neurons

The present study examined interactions between mu and delta opiate subtypes and serotonin. Noxious activity evoked by radiant heat (51 degrees C, 8 sec) was extracellularly recorded from single discriminated wide dynamic range (WDR) neurons in decerebrate spinally transected cats. DAGO (mu selective opioid agonist) 1 microgram or DPDPE (delta selective opioid agonist) 30 micrograms was combined with serotonin (n = 6 each) 250 micrograms. The dose of each drug by itself when administered intrathecally produced no suppression of noxiously evoked activity. Although the combination of DAGO and serotonin produced no significant suppression of noxiously evoked activity, DPDPE and serotonin produced significant suppression to 72.8 +/- 8.0 % (mean +/- SEM) of control values (P < 0.01). Intravenously administered naloxone 0.1 mg reversed the suppression produced by the DPDPE-serotonin combination. Our results suggest that combinations of serotonin and delta selective opiates may be more effective in suppressing noxiously evoked activity than combinations with mu selective opiates.     

An approximation to the steady state probabilities of a multi-echelon repair model for a series system

A multi-echelon repair system is often employed for the repair of a complex device. There have been many papers on a multi-echelon repair system. Most of them, however, treat the case that i) the repair system has one central repair station(two-echelon repair model), ii)the device is a single item system. The purpose of this paper is to extend a two-echelon repair model with single item systems to a multi-echelon repair model with multi-item systems. This extension makes the repair model more realistic. Then an approximation method to obtain the steady state probabilities of the repair model is presented. This method obtains the probabilities rapidly and accurately. The reliability measure considered in this model is the system availability. It is obtained as a byproduct of the steady state probabilities.     

CIS3 and JAB have different regulatory roles in interleukin-6 mediated differentiation and STAT3 activation in M1 leukemia cells

We have reported JAK-signaling modulators, CIS1 (cytokine-inducible SH2 protein-1), CIS3 and JAB (JAK2 binding protein), which are structurally related. In M1 myeloid leukemia cells, CIS3 was induced by neither interleukin 6 (IL6) nor interferon gamma (IFNgamma), while JAB was induced strongly by IFNgamma and slightly by IL6 and leukemia inhibitory factor (ILF). Forced expression of CIS3 and JAB in M1 cells prevented IL6- or LIF-induced growth arrest and differentiation, even when their expression levels were comparable to endogenous ones in several cell lines such as HEL, UT-7, IFNgamma-treated M1, and CTLL2 cells. Pretreatment of parental M1 cells with IFNgamma but not IFNbeta resulted in suppression of LIF-induced STAT3 activation and differentiation, further supporting that physiological level of JAB is sufficient to inhibit LIF-signaling. However, unlike JAB, CIS3 did not inhibit IFNgamma-induced growth arrest, suggesting a difference in cytokine specificity between CIS3 and JAB. CIS3 inhibited STAT3 activation with slower kinetics than JAB and allowed rapid c-fos induction and partial FcgammaRI expression in response to IL6. In 293 cells, CIS3 as well as JAB bound to JAK2 tyrosine kinase domain (JH1), and inhibited its kinase activity, however, the effect of CIS3 on tyrosine kinase activity was weaker than that of JAB, indicating that CIS3 possesses lower affinity to JAK kinases than JAB. These findings suggest that CIS3 is a weaker inhibitor than JAB against JAK signaling, and JAB and CIS3 possess different regulatory roles in cytokine signaling.