炎症反应在NAFLD发病中的作用研究进展

非酒精性脂肪性肝病（NAFLD）是临床上最为常见的的肝病之一,炎症反应贯穿了NAFLD整个病变过程,其发病机制尚未完全阐明。目前认为胰岛素抵抗（IR）、氧化应激以及内质网应激（ERS）在NAFLD发病中起着重要作用。就炎症反应通过参与IR、氧化应激和ERS影响NAFLD进展作一综述。     

FPGA原型验证平台信令协议仿真测试系统设计

通过定义一套基于PC串口的数据链路协议来实现在PC端对FPGA原型验证系统的通信及信令协议的仿真测试,详细说明了自定义的用户通信协议和串口通信方式;实现了FPGA原型验证平台上信令协议的测试系统;提出了信令系统的具体测试实例和结果分析。该通信协议和测试系统在实际工作中取得了令人满意的效果。     

一种针对乒乓移动节点的QoS快速无缝切换机制

本文在分层移动IPv6框架下对节点的乒乓式移动进行了研究,提出了一种与分层框架相吻合的快速无缝切换机制.该机制通过设置资源预留激活标记和离线倒计时,有效地减少了QoS切换信令并降低了切换时延,从而降低了网络传输负担和用户服务中断概率.移动节点可根据自身移动特性设置适当的离线倒计时间隔,以使多个邻近区域内的资源预留能 获得更好的性价比.     

ATM LAN实现技术的研究

ＡＴＭ ＬＡＮ是目前高速避域网的一个重要发展方向。文中在介绍了ＡＴＭ ＬＡＮ实现的主要技术途径及自行开发研制的ＧａＴＭ系统设计方案之后对ＡＴＭ ＬＡＮ实现的关键技术及存在的问题进行了深入的讨论。     

无线Ad Hoc网络支持QoS的研究进展与展望

无线ad hoc网络的应用环境以及与Internet的互连要求它必须提供一定的服务质量(QoS)保证,然而,无线信道固有的特点及节点移动造成网络拓扑的频繁变化,使得在无线ad hoc网络中支持QoS面临许多新的挑战.从无线ad hoc网络的QoS体系结构、QoS路由、QoS信令、支持业务区分和资源预留的介质访问控制协议这4个方面出发,对近年来国内外在该方向取得的研究成果作了全面的概括总结和比较分析,系统阐述了在无线ad hoc网络中支持QoS的问题,指出了亟待解决的问题和今后的研究方向.     

三峡枢纽梯级调度交换网的组建

三峡枢纽梯级调度交换网由3种机型、6套交换机、10多部调度台，多种信令接口方式组成。担负着国调至三峡梯调，三峡梯调至三峡左岸电站，三峡梯调至葛洲坝大江电厂和二江电厂，三峡船闸至枢纽等有关单位的调度通信。文中以组网方式及信令接口为主，介绍三峡枢纽梯级调度交换网的特点及信令接口。     

Efficient Total Chemical Synthesis of 13C=18O Isotopomers of Human Insulin for Isotope‐Edited FTIR

Isotope‐edited two‐dimensional Fourier transform infrared spectroscopy (2 D FTIR) can potentially provide a unique probe of protein structure and dynamics. However, general methods for the site‐specific incorporation of stable ¹³C=¹⁸O labels into the polypeptide backbone of the protein molecule have not yet been established. Here we describe, as a prototype for the incorporation of specific arrays of isotope labels, the total chemical synthesis—via a key ester insulin intermediate—of 97 % enriched [(1‐¹³C=¹⁸O)Phe^B24] human insulin: stable‐isotope labeled at a single backbone amide carbonyl. The amino acid sequence as well as the positions of the disulfide bonds and the correctly folded structure were unambiguously confirmed by the X‐ray crystal structure of the synthetic protein molecule. In vitro assays of the isotope labeled [(1‐¹³C=¹⁸O)Phe^B24] human insulin showed that it had full insulin receptor binding activity. Linear and 2 D IR spectra revealed a distinct red‐shifted amide I carbonyl band peak at 1595 cm^?1 resulting from the (1‐¹³C=¹⁸O)Phe^B24 backbone label. This work illustrates the utility of chemical synthesis to enable the application of advanced physical methods for the elucidation of the molecular basis of protein function.     

The PKR/P38/RIPK1 Signaling Pathway as a Therapeutic Target in Alzheimer’s Disease

Neuropathological lesions in Alzheimer’s disease (AD) include amyloid plaques formed by the accumulation of amyloid peptides, neurofibrillary tangles made of hyperphosphorylated tau protein, synaptic and neuronal degenerations, and neuroinflammation. The cause of AD is unknown, but according to the amyloid hypothesis, amyloid oligomers could lead to the activation of kinases such as eukaryotic translation initiation factor 2-alpha kinase 2 (PKR), p38, and receptor-interacting serine/threonine-protein kinase 1 (RIPK1), which all belong to the same stress-activated pathway. Many toxic kinase activations have been described in AD patients and in experimental models. A p38 mitogen-activated protein kinase inhibitor was recently tested in clinical trials but with unsuccessful results. The complex PKR/P38/RIPK1 (PKR/dual specificity mitogen-activated protein kinase kinase 6 (MKK6)/P38/MAP kinase-activated protein kinase 2 (MK2)/RIPK1) is highly activated in AD brains and in the brains of AD transgenic animals. To delineate the implication of this pathway in AD, we carried out a search on PubMed including PKR/MKK6/p38/MK2/RIPK1, Alzheimer, and therapeutics. The involvement of this signaling pathway in the genesis of AD lesions, including Aβ accumulations and tau phosphorylation as well as cognitive decline, is demonstrated by the reports described in this review. A future combination strategy with kinase inhibitors should be envisaged to modulate the consequences for neurons and other brain cells linked to the abnormal activation of this pathway.     

Optimal homeostasis necessitates bistable control

Bistability is a fundamental phenomenon in nature. In biology, a number of fine properties of bistability have been identified. However, these properties are only consequences of bistability at the physiological level, which do not explain why it had to emerge during evolution. Using optimal homeostasis as the first principle, I find that bistability emerges as an indispensable control mechanism. It is the only solution to a dilemma in glucose homeostasis: high insulin efficiency is required to confer rapidness in plasma glucose clearance, whereas an insulin sparing state is required to guarantee the brain''s safety during fasting. The optimality consideration renders a clear correspondence between the molecular and physiological levels. This new perspective can illuminate studies on the twin epidemics of obesity and diabetes and the corresponding intervening strategies. For example, overnutrition and sedentary lifestyle may represent sudden environmental changes that cause the lose of optimality, which may contribute to the marked rise of obesity and diabetes in our generation. Because this bistability result is independent of the parameters of the mathematical model (for which the result is quite general), some other biological systems may also use bistability to control homeostasis.     

Thermo‐ and pH‐responsive microgels for controlled release of insulin

Microgel particles were prepared, made of hydroxypropylcellulose‐graft‐(acrylic acid) (HPC‐g‐AA) and acrylic acid(AA). The particles undergo reversible volume phase transitions in response to both pH and temperature changes while keeping the inherent properties of PAA and HPC‐g‐AA. Dynamic light scattering measurements reveal that the average hydrodynamic radius and hydrodynamic radius distributions of the microgel particles depend on temperature and pH. The microgels exhibit excellent pH sensitivity and a higher swelling ratio at higher pH in aqueous solution. In vitro release study shows that the amount of insulin released from the microgels is less at pH = 1.2 than at pH = 6.8. The results indicate that the resultant microgels seem to be of great potential for intelligent oral drug delivery. Copyright © 2012 Society of Chemical Industry