An Energy-Efficient MAC Protocol for WSNs: Game-Theoretic Constraint Optimization with Multiple Objectives

In WSNs, energy conservation is the primary goal, while throughput and delay are less important. This re-sults in a tradeoff between performance (e.g., throughput, delay, jitter, and packet-loss-rate) and energy con-sumption. In this paper, the problem of energy-efficient MAC protocols in WSNs is modeled as a game-theoretic constraint optimization with multiple objectives. After introducing incompletely cooperative game theory, based on the estimated game state (e.g., the number of competing nodes), each node independ-ently implements the optimal equilibrium strategy under the given constraints (e.g., the used energy and QoS requirements). Moreover, a simplified game-theoretic constraint optimization scheme (G-ConOpt) is pre-sented in this paper, which is easy to be implemented in current WSNs. Simulation results show that G-ConOpt can increase system performance while still maintaining reasonable energy consumption.

Seroepidemiology and genetic characterization of hepatitis E virus in western Yunnan Province

Objective:To investigate the seroepidemiology and genetic characterization of hepatitis E virus(HEV) in western Yunnan Province.Methods:Questionnaire survey was conducted among1638 residents in western Yunnan Province using stratified sampling method.Enzyme-linked immunosorbent assay was used to detect serum anti-HEV IgG and IgM.HEV RNA was extracted from patients with serum anti-HEV IgM positive.The open reading flame 2(ORF2) of HEV that was amplified by nested RT-PCR was sequenced and compared with standard HEV genotypes 1-4.Results:Serum anti-HEV positive was found in 13.929(228/1638) residents.The HEV infection rate in males was significantly higher than that in females with a ratio of 1.47(P<0.01).20-30 and30-40 years old young men showed the highest incidence.20.57%and 20.78%.respectively.While10-20 and 20-30 years old young women exhibited the highest infection rate,11.85%and 15.60%,respectively.According to occupation,the highest HEV infection rate was observed in farmers(20.35%) and migrants(16.50%).We isolated 10 individual HEV isolates from 31 patients with serum anti-HEV IgM positive.Homology analysis and phylogenetic analysis indicated that these10 HEV isolates belonged to HEV genotype 4 with the homology of 78.65%-94.71%.Conclusions:The HEV infection rate is high in western Yunnan Province.HEV genotype 4 is the leading cause of HEV infection and young farmers and migrants are the main infected population.

考虑牵引网线路参数频变的相模变换矩阵计算

针对现有的相模变换矩阵不能满足线路参数随频率变化的牵引网多导线系统的解耦计算,本文提出了一种适用于该情形的相模变换矩阵的计算方法,即根据特征向量和特征值的数学关系并利用LM(levenberg-marquardt)算法来实现特征向量的近似迭代,结果表明可以保证相模变换矩阵在频域内的平滑连续性,综合对比其他相模变换矩阵的计算方法得出的相速度,证明了该方法的可行性和准确性。

PtAu bimetallic nanocatalyst for selective hydrogenation of alkenes over aryl halides

Herein,we present a new strategy that for the first time achieved chemo- and enantio-selective hydrogenation of alkenes over arylhalides.Key to the success is that instead of using external poisons,we use the composition of the bimetallic nanocrystal catalysts to control chemoselectivity (hydrogenation of C=C bonds without cleavage of Ar-X bonds).We further show that this system combined with surface modifying chiral ligands can control the enantioselectivity.Thus,after synthesizing and screening a series of easily accessible MxAuy (M = Pd,Pt;x,y= 1,3,5) bimetallic nanocrystals (9-10 nm) supported on activated carbon,we identified that PtiAui/C is a recyclable and generally applicable catalyst for the chemoselective hydrogenation of alkenes without cleaving aryl halogen bonds.Furthermore,cinchonidine modified Pt,Aui/C is shown to be capable of enantioselective hydrogenation,as illustrated by the rapid and enantio-enriched synthesis of RIP1 inhibitor analogue 7-Br-O-Necl.

A midgut transcriptional regulatory loop favors an insect host to withstand a bacterial pathogen

Mounting evidence suggests that insect hormones associated with growth and development also participate in pathogen defense.We have discovered a previously undescribed midgut transcriptional control pathway that modulates the availability of 20-hydroxyecdysone(20E)in a worldwide insect pest(Plutella xylostella),allowing it to defeat the major virulence factor of an insect pathogen Bacillus thuringiensis(Bt).A reduction of the transcriptional inhibitor(PxDfd)increases the expression of a midgut microRNA(miR-8545),which in turn represses the expression of a newly identified ecdysteroid-degrading glucose dehydrogenase(PxGLD).Downregulation of PxGLD reduces 20E degradation to increase 20E titer and concurrently triggers a transcriptional negative feedback loop to mitigate 20E overproduction.The moderately elevated 20E titer in the midgut activates a MAPK signaling pathway to increase Bt tolerance/resistance.These findings deepen our understanding of the functions attributed to these classical insect hormones and help inform potential future strategies that can be employed to control insect pests.

幽门螺旋杆菌重组抗原表位肽C-CagAL构建及其多克隆抗体特异性分析

[目的]制备幽门螺旋杆菌重组抗原表位肽C-CagAL,并分析其多克隆抗血清的特异性。[方法]用分子克隆技术构建重组表达质粒pETC-CagAL,将其转入大肠杆菌中表达,利用Ni-Agarose亲和层析纯化目的蛋白C-CagAL;免疫BALB/c小鼠,制备抗C-CagAL多克隆抗血清,通过ELISA方法分析抗血清的特异性。[结果]DNAstar等软件表明C-CagAL具有较好的抗原性,Linker易形成转角或β-折叠,为柔性结构;重组抗原C-CagAL经大肠杆菌表达,约56kDa,占菌体总蛋白的19.82%,经Ni-Agarose亲和层析纯化,获得纯度为97.5%的重组抗原C-CagAL;抗C-CagAL多克隆抗血清能够特异性识别CagA和CagL。[结论]获得了一种能够激发抗CagA和CagL特异性抗体的重组抗原表位肽C-CagAL,为进一步研究其预防幽门螺旋杆菌感染的免疫效果奠定了基础。