The Quiescent Cellular State is Arf/p53-Dependent and Associated with H2AX Downregulation and Genome Stability

Cancer is a disease associated with genomic instability and mutations. Excluding some tumors with specific chromosomal translocations, most cancers that develop at an advanced age are characterized by either chromosomal or microsatellite instability. However, it is still unclear how genomic instability and mutations are generated during the process of cellular transformation and how the development of genomic instability contributes to cellular transformation. Recent studies of cellular regulation and tetraploidy development have provided insights into the factors triggering cellular transformation and the regulatory mechanisms that protect chromosomes from genomic instability.     

基于PIC16F877的终端结点控制器的设计与实现

介绍了国际业余无线电联盟公布的分组无线网的AX.25协议,并对分组无线网的AX.25协议有限状态机模型进行了分析。提出了基于AX.25协议构成分组无线网的方案,给出了基于AX.25协议的终端结点控制器(TNC)的硬件和软件实现方法。结合终端结点控制器、收发设备和具有标准RS-232接口的计算机连接方案,说明了实现无线分组通信的方法。     

Evaluation of Calyculin A Effect on γH2AX/53BP1 Focus Formation and Apoptosis in Human Umbilical Cord Blood Lymphocytes

Dephosphorylation inhibitor calyculin A (cal A) has been reported to inhibit the disappearance of radiation-induced γH2AX DNA repair foci in human lymphocytes. However, other studies reported no change in the kinetics of γH2AX focus induction and loss in irradiated cells. While apoptosis might interplay with the kinetics of focus formation, it was not followed in irradiated cells along with DNA repair foci. Thus, to validate plausible explanations for significant variability in outputs of these studies, we evaluated the effect of cal A (1 and 10 nM) on γH2AX/53BP1 DNA repair foci and apoptosis in irradiated (1, 5, 10, and 100 cGy) human umbilical cord blood lymphocytes (UCBL) using automated fluorescence microscopy and annexin V-FITC/propidium iodide assay/γH2AX pan-staining, respectively. No effect of cal A on γH2AX and colocalized γH2AX/53BP1 foci induced by low doses (≤10 cGy) of γ-rays was observed. Moreover, 10 nM cal A treatment decreased the number of all types of DNA repair foci induced by 100 cGy irradiation. 10 nM cal A treatment induced apoptosis already at 2 h of treatment, independently from the delivered dose. Apoptosis was also detected in UCBL treated with lower cal A concentration, 1 nM, at longer cell incubation, 20 and 44 h. Our data suggest that apoptosis triggered by cal A in UCBL may underlie the failure of cal A to maintain radiation-induced γH2AX foci. All DSB molecular markers used in this study responded linearly to low-dose irradiation. Therefore, their combination may represent a strong biodosimetry tool for estimation of radiation response to low doses. Assessment of colocalized γH2AX/53BP1 improved the threshold of low dose detection.     

Release of phenolic flavour precursors during wort production: Influence of process parameters and grist composition on ferulic acid release during brewing

In this study, the effects of mashing variables such as mashing-in temperature, time and pH, mash thickness, grist coarseness and composition, and stirring regime on the release of ferulic acid were examined. Ferulic acid is a precursor for the formation of flavour-active volatile phenols and a potent natural antioxidant in beer. Given one barley malt variety, the multitude of choice in setting various process parameters and adding brewery adjuncts during brewhouse operations can give rise to worts with widely varying ferulic acid levels. A clear difference in temperature- and pH-dependence between the release of the water-extracted and the enzymatically hydrolyzed fraction was found. The T,t-dependencies of arabinoxylan-degrading enzyme activities were correlated with ferulic acid release during mashing. Results from laboratory-scale mashing experiments were validated with those from a pilot-scale (5 h) wort production process. Enhancing the enzymatic release of phenolic flavour precursors from bound forms during mashing can greatly enhance the phenolic aroma potential of wort. Optimising this precursor release during mashing may be a means for controlling final volatile phenol levels in beer.     

Sustained Activation of TNFα-Induced DNA Damage Response in Newly Differentiated Adipocytes

The response to DNA damage is the mechanism that allows the interaction between stress signals, inflammatory secretions, DNA repair, and maintenance of cell and tissue homeostasis. Adipocyte dysfunction is the cellular trigger for various disease states such as insulin resistance, diabetes, and obesity, among many others. Previously, our group demonstrated that adipogenesis per se, from mesenchymal/stromal stem cells derived from human adipose tissue (hASCs), involves an accumulation of DNA damage and a gradual loss of the repair capacity of oxidative DNA damage. Therefore, our objective was to identify whether healthy adipocytes differentiated for the first time from hASCs, when receiving inflammatory signals induced with TNFα, were able to persistently activate the DNA Damage Response and thus trigger adipocyte dysfunction. We found that TNFα at similar levels circulating in obese humans induce a sustained response to DNA damage response as part of the Senescence-Associated Secretory Phenotype. This mechanism shows the impact of inflammatory environment early affect adipocyte function, independently of aging.     

In Vitro Evaluation of No-Carrier-Added Radiolabeled Cisplatin ([189, 191Pt]cisplatin) Emitting Auger Electrons

Due to their short-range (2–500 nm), Auger electrons (Auger e⁻) have the potential to induce nano-scale physiochemical damage to biomolecules. Although DNA is the primary target of Auger e⁻, it remains challenging to maximize the interaction between Auger e⁻ and DNA. To assess the DNA-damaging effect of Auger e⁻ released as close as possible to DNA without chemical damage, we radio-synthesized no-carrier-added (n.c.a.) [^{189, 191}Pt]cisplatin and evaluated both its in vitro properties and DNA-damaging effect. Cellular uptake, intracellular distribution, and DNA binding were investigated, and DNA double-strand breaks (DSBs) were evaluated by immunofluorescence staining of γH2AX and gel electrophoresis of plasmid DNA. Approximately 20% of intracellular radio-Pt was in a nucleus, and about 2% of intra-nucleus radio-Pt bound to DNA, although uptake of n.c.a. radio-cisplatin was low (0.6% incubated dose after 25-h incubation), resulting in the frequency of cells with γH2AX foci was low (1%). Nevertheless, some cells treated with radio-cisplatin had γH2AX aggregates unlike non-radioactive cisplatin. These findings suggest n.c.a. radio-cisplatin binding to DNA causes severe DSBs by the release of Auger e⁻ very close to DNA without chemical damage by carriers. Efficient radio-drug delivery to DNA is necessary for successful clinical application of Auger e⁻.     

基于AX88796B的网络接口设计与实现

介绍了一种基于AX88796B的网络接口设计。详细介绍了该网络芯片的硬件结构和功能特性。创新完成了AX88796B与DSP处理器TMS320C6722连接的硬件设计和软件驱动设计。涉及的关键技术主要有AX88796B的本地总线连接、物理层网络驱动的设计、网络报文的发送、网络报文的接收,以及协议层软件的开发。系统完成后与其他网络设备连接,经测试,网络通信稳定可靠,在100Mb／s的速度,负荷超过90％的情况下,没有丢包和错包出现,可以满足大数据量、高速通信的要求。     

基于ZigBee技术的温湿度监测网络设计与实现

无线传感器网络是当前信息领域中研究的热点之一,可用于特殊环境实现信号的采集、处理和发送。文中介绍了一种基于ZigBee技术的温、湿度监测网络的设计与实现,以CC2430单片机和数字式温、湿度传感器SHT10设计出了温、湿度传感器节点,以AT91R4008微控制器、AX88796以太网控制器芯片和CC2430单片机设计出了ZigBee无线网关。温湿度传感器节点通过射频收发器将数据发送到ZigBee无线网关。ZigBee无线网关通过以太网网络将数据传输给监测中心主机。该系统具有低功耗、高可靠性、易组网及稳定性好等优势,可广泛应用于工业环境温、湿度监测。