CST2003智能数字压力校验仪电源适配器原理检修及完善

本文简要介绍CST2003智能数字压力校验仪电源适配器输原理与典型故障维修,并根据实际情况提出完善措施。     

用全耗尽绝缘硅互补型金属氧化物半导体集成技术实现ー种激光测距电路

在对薄膜全耗尽绝缘硅互补型金属氧化物半导体( SOICMOS)结构进行模拟和测试基础上，采用薄膜全耗尽绝缘硅(SOI)结构，并在工艺中利用优质栅氧化、Ti硅化物、轻掺杂漏(LDD)结构等关键技术实现了一种高速低功耗SOI CMOS激光测距集成电路。测试结果表明：1.2μm器件101级环振单门延迟为252 ps，总延迟为54.2 ns．电路静态功耗约为3mW，动态功耗为15 mW.     

Full range voltage-controlled ring oscillator in 0.18μm CMOS for low-voltage operation

A new differential delay cell with a complementary current control to increase the control voltage range as well as the operation frequency is proposed for low-voltage operation. The new differential delay cell is employed in a four-stage voltage-controlled ring oscillator (VCRO). The VCRO is implemented using 0.18 m 1P6M CMOS process and 1.8 V supply voltage. Measured results show that a wide operation frequency range from 5.36 to 3.03 GHz is achieved for the full range control voltage from 0 to 1.8 V. Measured phase noise is 107 dBc/Hz at 1 MHz offset from the 5.22 GHz centre frequency.     

Time-Course Changes of Steroidogenic Gene Expression and Steroidogenesis of Rat Leydig Cells after Acute Immobilization Stress

Leydig cells secrete testosterone, which is essential for male fertility and reproductive health. Stress increases the secretion of glucocorticoid (corticosterone, CORT; in rats), which decreases circulating testosterone levels in part through a direct action by binding to the glucocorticoid receptors (NR3C1) in Leydig cells. The intratesticular CORT level is dependent on oxidative inactivation of glucocorticoid by 11β-hydroxysteroid dehydrogenase 1 (HSD11B1) in Leydig cells. In the present study, we investigated the time-course changes of steroidogenic gene expression levels after acute immobilization stress in rats. The plasma CORT levels were significantly increased 0.5, 1, 3 and 6 h after immobilization stress, while plasma testosterone levels were significantly reduced 3 and 6 h, after stress and luteinizing hormone (LH) did not change. Immobilization stress caused the down-regulation of Scarb1, Star and Cyp17a1 expression levels in the rat testis starting at the first hour of stress, ahead of the significant decreases of plasma testosterone levels. Other mRNA levels, including Cyp11a1, Hsd3b1 and Hsd17b3, began to decline after 3 h. Hsd11b1 and Nos2 mRNA levels did not change during the course of stress. Administration of glucocorticoid antagonist RU486 significantly restored plasma testosterone levels. In conclusion, Scarb1, Star and Cyp17a1 expression levels are more sensitive to acute stress, and acute immobilization stress causes the decline of the steroidogenic pathway via elevating the levels of glucocorticoid, which binds to NR3C1 in Leydig cells to inhibit steroidogenic gene expression.     

智慧教育背景下大学生学习环境重构研究

传统的线下教学和线上教学都存在部分弊病,为避免单场所教学的弱势,结合这两个教学平台的优点,本研究试图基于班杜拉的社会学习理论,探究智慧教育背景下如何重构大学生的学习环境,从而提升教学效果,为智慧教育的进一步发展探明方向。     

Cartilage Oligomeric Matrix Protein Gene Multilayers Inhibit Osteogenic Differentiation and Promote Chondrogenic Differentiation of Mesenchymal Stem Cells

There are still many challenges to acquire the optimal integration of biomedical materials with the surrounding tissues. Gene coatings on the surface of biomaterials may offer an effective approach to solve the problem. In order to investigate the gene multilayers mediated differentiation of mesenchymal stem cells (MSCs), gene functionalized films of hyaluronic acid (HA) and lipid-DNA complex (LDc) encoding cartilage oligomeric matrix protein (COMP) were constructed in this study via the layer-by-layer self-assembly technique. Characterizations of the HA/DNA multilayered films indicated the successful build-up process. Cells could be directly transfected by gene films and a higher expression could be obtained with the increasing bilayer number. The multilayered films were stable for a long period and DNA could be easily released in an enzymatic condition. Real-time polymerase chain reaction (RT-PCR) assay presented significantly higher (p < 0.01) COMP expression of MSCs cultured with HA/COMP multilayered films. Compared with control groups, the osteogenic gene expression levels of MSCs with HA/COMP multilayered films were down-regulated while the chondrogenic gene expression levels were up-regulated. Similarly, the alkaline phosphatase (ALP) staining and Alizarin red S staining of MSCs with HA/COMP films were weakened while the alcian blue staining was enhanced. These results demonstrated that HA/COMP multilayered films could inhibit osteogenic differentiation and promote chondrogenic differentiation of MSCs, which might provide new insight for physiological ligament-bone healing.     

Resveratrol Partially Prevents Rotenone-Induced Neurotoxicity in Dopaminergic SH-SY5Y Cells through Induction of Heme Oxygenase-1 Dependent Autophagy

Parkinson disease (PD) is a complex neurodegenerative disorder characterized by a progressive loss of dopaminergic neurons. Mitochondrial dysfunction, oxidative stress or protein misfolding and aggregation may underlie this process. Autophagy is an intracellular catabolic mechanism responsible for protein degradation and recycling of damaged proteins and cytoplasmic organelles. Autophagic dysfunction may hasten the progression of neuronal degeneration. In this study, resveratrol promoted autophagic flux and protected dopaminergic neurons against rotenone-induced apoptosis. In an in vivo PD model, rotenone induced loss of dopaminergic neurons, increased oxidation of mitochondrial proteins and promoted autophagic vesicle development in brain tissue. The natural phytoalexin resveratrol prevented rotenone-induced neuronal apoptosis in vitro, and this pro-survival effect was abolished by an autophagic inhibitor. Although both rotenone and resveratrol promoted LC3-II accumulation, autophagic flux was inhibited by rotenone and augmented by resveratrol. Further, rotenone reduced heme oxygenase-1 (HO-1) expression, whereas resveratrol increased HO-1 expression. Pharmacological inhibition of HO-1 abolished resveratrol-mediated autophagy and neuroprotection. Notably, the effects of a pharmacological inducer of HO-1 were similar to those of resveratrol, and protected against rotenone-induced cell death in an autophagy-dependent manner, validating the hypothesis of HO-1 dependent autophagy in preventing neuronal death in the in vitro PD model. Collectively, our findings suggest that resveratrol induces HO-1 expression and prevents dopaminergic cell death by regulating autophagic flux; thus protecting against rotenone-induced neuronal apoptosis.     

基于SOI材料的兵器微电子技术应用分析

随着集成技术进入亚微米阶段,传统的硅基集成电路由于存在闩锁等不利因素,使其应用受到了限制。而基于SOI材料的微电子技术是能突破硅材料与硅集成电路限制的新技术,是国际半导体的前沿技术之一,是发展兵器装备用元器件的又一关键材料技术。介绍了SOI材料结构技术用于微电子器件的优势、SOI结构及基于SOI结构材料的兵器微电子技术应用,展望了SOI技术的发展前景。     

魅力畅想曲 3款特色橱柜鉴赏

大自然总是可以给人带来无穷的力量，艾度维ONICE橱柜以清新舒适为最大特色，橡木贴面门板纹理自然，洋溢着令人沉醉的大自然的气息，为闷热的夏季带来几分宁静，简洁内敛的设计风格，宽敞的厨房空间，让人仿佛置身于大自然的怀抱中，