Hadoop-based secure storage solution for big data in cloud computing environment

In order to address the problems of the single encryption algorithm,such as low encryption efficiency and unreliable metadata for static data storage of big data platforms in the cloud computing environment,we propose a Hadoop based big data secure storage scheme.Firstly,in order to disperse the NameNode service from a single server to multiple servers,we combine HDFS federation and HDFS high-availability mechanisms,and use the Zookeeper distributed coordination mechanism to coordinate each node to achieve dual-channel storage.Then,we improve the ECC encryption algorithm for the encryption of ordinary data,and adopt a homomorphic encryption algorithm to encrypt data that needs to be calculated.To accelerate the encryption,we adopt the dualthread encryption mode.Finally,the HDFS control module is designed to combine the encryption algorithm with the storage model.Experimental results show that the proposed solution solves the problem of a single point of failure of metadata,performs well in terms of metadata reliability,and can realize the fault tolerance of the server.The improved encryption algorithm integrates the dual-channel storage mode,and the encryption storage efficiency improves by 27.6% on average.

基于网络药理学和分子对接技术研究四鲜汤治疗急性白血病的作用机制

目的:利用网络药理学和分子对接技术对四鲜汤治疗急性白血病(AcuteLeukemia,AL)的作用机制进行研究。方法:通过中药系统药理学数据库与分析平台(Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform,TCMSP)、中药分子机制生物信息学分析工具(Bioinformatics Analysis Tool for Molecular Mechanism of Traditional Chinese Medicine,BATMAN—TCM)和中医药百科全书数据库(Encyclopedia of Traditional Chinese Medicine,ETCM)检索并获取鲜药复方四鲜汤组方中药(生地、白茅根、小蓟、蒲公英)的化学成分,建立鲜药复方-四鲜汤的天然药物活性化学成分数据集;检索人类基因数据库(Human Gene Data Base,Gencards)、人类疾病相关基因和变异的信息的数据库(Database of Gene-Disease Associations,DisGeNET)、在线生物信息学和化学信息学数据库(Database for Drug and Drug Target Info,DrugBank)、人类疾病数据库(Human Disease Database,MalaCards)以获得AL疾病相关靶点,建立疾病靶点数据库。获取药物以及疾病的交集靶点后,在线画出两者共同靶点venn图;利用String11.5平台构建药物疾病蛋白互作网络;利用cytoscape3.8.2软件构建“药物—疾病—靶点—信号通路”网络,获取相关靶点网络拓扑参数。结果:经TcMSp\BAT-MAN—TcM和ETcM三个数据库检索,获得四鲜汤活性成分30个,相关靶点677个;通过Gencards、DrugBank、MalaCards和DisGeNET四个数据库获得12110个AL疾病潜在靶点;通过R4.2.2平台的ClusterProfiler软件包获得生物功能富集(Gene Ontology,GO)信息条目1011条,其中生物过程(Biological Process,BP)467条,分子功能(Molecular Function,MF)236条,细胞组分(Cellular Component,CC)308条;获得富集的京都基因与基因组百科全书(Kyoto Encyclopedia of Genesand Genomes,KEGG)信号通路220条,主要涉及化学致癌受体激活、脂质与动脉粥样硬化、流体剪切力与动脉粥样硬化、前列腺癌、AGE-RAGE信号通路在糖尿病并发症中的作用等;网络拓扑分析发现,四鲜汤治疗AL疾病作用的主要活性成分有γ-氨基丁酸、腺嘌呤核苷、槲皮素、东莨菪碱和蒲公英萜醇等化合物。结论:四鲜汤治疗AL是一种多成分多靶点多信号通路的共同调节过程,网络药理学为阐明四鲜汤治疗AL的作用机理提供了坚实的研究基础。

腹膜后肿瘤切除术后胃排空障碍的危险因素分析

目的:探讨腹膜后肿瘤切除术后出现功能性胃排空障碍(functional delayed gastric emptying,FDGE)的危险因素。方法:回顾性分析2017年9月至2022年12月于北京大学国际医院行腹膜后肿瘤切除术后出现FDGE的患者67例(观察组),选择同期836例未出现FDGE的腹膜后肿瘤切除术患者作为对照组,调查和对比两组患者的病史及临床诊治资料,观察腹膜后肿瘤切除术后影响FDGE发生的危险因素。结果:全部患者总体术后FDGE发生率为(7.42%)。观察组存在不良精神因素(37.31%)、术前消化道梗阻(41.79%)、术后腹腔并发症(79.10%)、糖尿病(29.86%)的比例高于对照组,同时在年龄(61.85±6.11)岁、出血量(1011.94±507.30)mL方面高于对照组,差异具有统计学意义(P<0.05)。观察组术前白蛋白水平(38.22±3.75)g/L、术后白蛋白水平(30.22±3.36)g/L低于对照组,差异具有统计学意义(P<0.05)。危险因素分析显示,高龄、糖尿病、术前消化道梗阻、术中出血量、围手术期白蛋白水平、术后腹腔并发症、不良精神因素是术后发生FDGE的影响因素。结论:导致腹膜后肿瘤切除术后胃排空障碍的影响因素种类众多,应予以准确评估,制定合理、详细的预防和诊疗计划。

Designing interstitial boron-doped tunnel-type vanadium dioxide cathode for enhancing zinc ion storage capability

Chemical doping is a powerful method to intrinsically tailor the electrochemical properties of electrode materials.Here,an interstitial boron-doped tunnel-type VO_(2)(B)is constructed via a facile hydrothermal method.Various analysis techniques demonstrate that boron resides in the interstitial site of VO_(2)(B)and such interstitial doping can boost the zinc storage kinetics and structural stability of VO_(2)(B)cathode during cycling.Interestingly,we found that the boron doping level has a saturation limit peculiarity as proved by the quantitative analysis.Notably,the 2 at.%boron-doped VO_(2)(B)shows enhanced zinc ion storage performance with a high storage capacity of 281.7 mAh g^(-1) at 0.1 A g^(-1),excellent rate performance of 142.2 mAh g^(-1) at 20 A g^(-1),and long cycle stability up to 1000 cycles with the capacity retention of 133.3 mAh g^(-1) at 5 A g^(-1).Additionally,the successful preparation of the boron-doped tunneltype α-MnO_(2) further indicates that the interstitial boron doping approach is a general strategy,which supplies a new chance to design other types of functional electrode materials for multivalence batteries.

Detection of heavy metals in water samples by laser-induced breakdown spectroscopy combined with annular groove graphite flakes

The use of laser-induced breakdown spectroscopy(LIBS) for the analysis of heavy metals in water samples is investigated. Some factors such as splashing, surface ripples, extinction of emitted intensity, and a shorter plasma lifetime will influence the results if the water sample is directly measured. In order to avoid these disadvantages and the ‘coffee-ring effect', hydrophilic graphite flakes with annular grooves were used for the first time to enrich and concentrate heavy metals in water samples before being analyzed by LIBS. The proposed method and procedure have been evaluated to concentrate and analyze cadmium, chromium, copper, nickel, lead,and zinc in a water sample. The correlation coefficients were all above 0.99. The detection limits of 0.029, 0.087, 0.012, 0.083, 0.125, and 0.049 mgl^(-1) for Cd, Cr, Cu, Ni, Pb, and Zn,respectively, were obtained in samples prepared in a laboratory. With this structure, the heavy metals homogeneously distribute in the annular groove and the relative standard deviations are all below 6%. This method is very convenient and suitable for online in situ analysis of heavy metals.

Studies on Extracting Microcystin-Lr from Microcystis Aeruginosa by Water Bath

Different temperatures of water bath was used to extract the intracellular microcystin-LR(MC-LR) of Microcystis aeruginosa. Researching the extraction efficiency under the suitable temperature, so that it could find out the best temperature and time for extracting MC-LR from Microcystis aeruginosa cells. Five equal Microcystis aeruginosa was used to find out the best temperature, extracting at 60℃, 70℃, 80℃, 90℃ and 100℃ for 15 minutes, respectively. Results showed that the content of MC-LR extracted with the water under 100℃ was the highest. But meanwhile, the type and the content of impurities was the highest, too. In addition, another six equal Microcystis aeruginosa was extract with the water under 100℃ for 5min, 10 min, 15 min, 20 min, 25 min and 30 min respectively. It was proved that 20 minutes was enough for extracting MC-LR from Microcystis aeruginosa, no long time was needed.

Re effects in model Ni-based superalloys investigated with first-principles calculations and atom probe tomography

The phase partition and site preference of Re atoms in a ternary Ni-Al-Re model alloy,including the electronic structure of different Re configurations,are investigated with first-principles calculations and atom probe tomography.The Re distribution of single,nearest neighbor(NN),next-nearest neighbor(NNN),and cluster configurations are respectively designed in the models withγandγphases.The results show that the Re atoms tend to enteringγphase and the Re atoms prefer to occupy the Al sites inγphase.The Re cluster with a combination of NN and NNN Re-Re pair configuration is not preferred than the isolated Re atom in the Ni-based superalloys,and the configuration with isolated Re atom is more preferred in the system.Especially,the electronic states are analyzed and the energetic parameters are calculated.The electronic structure analyses show there exists strong Ni-Re electronic interaction and it is mainly contributed by the d-d hybridization.The characteristic features of the electronic states of the Re doping effects are also given.It is also found that Re atoms prefer the Al sites inγside at the interface.The density of states at or near the Fermi level and the d-d hybridizations of NN Ni-Re are found to be important in the systems.

Spin transport in epitaxial Fe3O4/GaAs lateral structured devices

Research in the spintronics community has been intensively stimulated by the proposal of the spin field-effect transistor(SFET),which has the potential for combining the data storage and process in a single device.Here we report the spin dependent transport on a Fe_(3)O_(4)/GaAs based lateral structured device.Parallel and antiparallel states of two Fe_(3)O_(4) electrodes are achieved.A clear MR loop shows the perfect butterfly shape at room temperature,of which the intensity decreases with the reducing current,showing the strong bias dependence.Understanding the spin-dependent transport properties in this architecture has strong implication in further development of the spintronic devices for room-temperature SFETs.

The fabrication,characterization and functionalization in molecular electronics

Developments in advanced manufacturing have promoted the miniaturization of semiconductor electronic devices to a near-atomic scale,which continuously follows the‘top-down’construction method.However,huge challenges have been encountered with the exponentially increased cost and inevitably prominent quantum effects.Molecular electronics is a highly interdisciplinary subject that studies the quantum behavior of electrons tunneling in molecules.It aims to assemble electronic devices in a‘bottom-up’manner on this scale through a single molecule,thereby shedding light on the future design of logic circuits with new operating principles.The core technologies in this field are based on the rapid development of precise fabrication at a molecular scale,regulation at a quantum scale,and related applications of the basic electronic component of the‘electrode-molecule-electrode junction’.Therefore,the quantum charge transport properties of the molecule can be controlled to pave the way for the bottom-up construction of single-molecule devices.The review firstly focuses on the collection and classification of the construction methods for molecular junctions.Thereafter,various characterization and regulation methods for molecular junctions are discussed,followed by the properties based on tunneling theory at the quantum scale of the corresponding molecular electronic devices.Finally,a summary and perspective are given to discuss further challenges and opportunities for the future design of electronic devices.

第四届国际差分吸收光谱环境研究与监测学术研讨会论文摘要集

由中国科学院安徽光学精密机械研究所承办，中国科学院、德国海德堡大学、大气组分变化欧洲卓越网络TROPOSAT－2（AT－2）项目指导委员会、安徽省光学学会协办的“第四届国际DOAS环境研究与监测学术研讨会”（the Fourth DOAS International Workshop for Environmental Researchand Monitoring）于2008年3月30日－4月3日在合肥召开。

Study on the Concentration Inversion of NO &NO2 Gas from the Vehicle Exhaust Based on Weighted PLS

It becomes a key technology to measure the concentration of the vehicle exhaust components with the absorption spectra. But because of the overlap of gas absorption bands, how to separate the absorption information of each component gas from the mixed absorption spectra has become the key point to restrict the precision of the optical detection method. In this paper, the ex-perimental platform for the absorption spectrum of vehicle exhaust components has been established. Based on the ultraviolet absorption spectra measured with the platform of exhaust gas NO & NO2, the concentration regression model for the two components has been established with weighted partial least squares regression (WPLS). Finally the each spectral characteristic information of NO & NO2 gas has been separated and the concentration of each corresponding component has been reversed successfully.

Recent advances,challenges,and perspectives on carbon capture

Carbon capture,utilization and storage(CCUS)technologies play an essential role in achieving Net Zero Emissions targets.Considering the lack of timely reviews on the recent advancements in promising CCUS technologies,it is crucial to provide a prompt review of the CCUS advances to understand the current research gaps pertained to its industrial application.To that end,this review first summarized the developmental history of CCUS technologies and the current large-scale demonstrations.Then,based on a visually bibliometric analysis,the carbon capture remains a hotspot in the CCUS development.Noting that the materials applied in the carbon capture process determines its performance.As a result,the state-of-the-art carbon capture materials and emerging capture technologies were comprehensively summarized and discussed.Gaps between state-of-art carbon capture process and its ideal counterpart are analyzed,and insights into the research needs such as material design,process optimization,environmental impact,and technical and economic assessments are provided.

Mechanical sensor PDLIM5 promotes the osteogenesis of human adipose-derived stem cells through microfilament alterations

Bone regeneration is a multifaceted,abstract,and wellcoordinated physiological progression of bone formation that participates in continuous regeneration and remodeling throughout life.However,when it comes to complex clinical situations requiring extensive bone regeneration,such as massive bone defects caused by injuries,infection,or tumor removal,traditional methods do not often yield good treatment strategies or protocols due to their limitations.

Needs and challenges of optical atmospheric monitoring on the background of carbon neutrality in China

The achievement of the targets of coordinated control of PM2.5 and O3 and the carbon peaking and carbon neutrality depend on the development of pollution and greenhouse gas monitoring technologies.Optical monitoring technology,based on its technical characteristics of high scalability,high sensitivity and wide-targets detection,has obvious advantages in pollution/greenhouse gases monitoring and has become an important direction in the development of environmental monitoring technology.At present,a system of environmental optical monitoring technology with differential optical absorption spectroscopy(DOAS),cavity ring-down spectroscopy(CRDS),light detection and ranging(LIDAR),laser heterodyne spectroscopy(LHS),tunable diode laser absorption spectroscopy(TDLAS),fourier transform infrared spectroscopy(FTIR)and fluorescence assay by gas expansion(FAGE)as the main body has been established.However,with the promotion of“reduction of pollution and carbon emissions”strategy,there have been significant changes in the sources of pollution/greenhouse gases,emission components and emission concentrations,which have put forward new and higher requirements for the development of monitoring technologies.In the future,we should pay more attention to the development of new optical monitoring techniques and the construction of stereoscopic monitoring system,the interdisciplinarity(among mathematics,physics,chemistry and biology,etc.),and the monitoring of greenhouse gases and research on atmospheric chemistry.

高度近视与青光眼的相关性

高度近视是原发性开角型青光眼重要的危险因素之一,但二者之间的相互作用关系尚未完全明确,且二者间的关联为早期诊治带来了困难。笔者从流行病学、遗传因素、结构特点和临床诊断等方面对高度近视与原发性开角型青光眼之间的联系进行述评,以期进一步加深对二者之间关联的认识,为临床早期诊断和治疗提供理论依据。

可相变的纳米析出相诱发亚稳低温钢的高延展性

纳米析出相在所有合金中都被用作额外的增强相,但大多数情况,特别是在低温环境下,纳米析出相的引入会严重降低材料的塑性和可加工性.这一强塑性倒置问题仍然亟待解决.基于此,本文发现了一种可相变的纳米析出相(TNP),通过其在变形过程的相变行为在亚稳基体中诱发了以微带和孪晶马氏体为主的多阶段变形机制.与不含TNP的低温钢相比,可持续的两阶段加工硬化能力使其在77 K下的屈服强度和均匀伸长率都能分别提高30%和65%.微带和析出相之间的交互作用不仅使微观结构得到动态细化,也将孪晶马氏体推迟至应变后期发生.此外,这一相变行为也可以缓解界面的错配应变,阻碍孪晶生长并获得更均匀的变形.这一研究结果证明了析出诱发塑性的创新机制,可为在极端环境下析出强化的应用提供新的方向.

环境空气质量基准和标准制定方法及其对我国的启示

我国已经在大气污染治理方面取得了显著成效,空气质量明显改善,积累了先进的空气污染治理经验.现阶段,我国应逐步开启对环境空气质量基准的研究.本文详细介绍了国际上主要的三大类环境空气质量基准和标准的制定原则与方法,分别基于人体健康、植被暴露以及土壤/水体生态系统化学指标;汇总比较了国际上较常采用的一系列评价指标.在此基础上,对我国上述三方面的本土化基础研究进行综述,分析了我国开展环境空气质量基准研究的原则性路径,包括工作初期和完善体系的预期架构,指出工作初期制定基准的工作可以适当从简,但在工作基础逐渐丰富后,应当逐步细化的工作原则.此外,本文还对国内外环境空气标准的制定策略中采纳基准的情况进行了简要的比较和梳理,结合我国环境空气达标现状、管理体系和工作基础,面向“美丽中国”和“健康中国”的宏伟目标,提出在科学构建环境空气质量评估体系的过程中,既要考虑我国本土人群健康与生态独特的安全红线,又要注意基准向标准转化过程可能带来的管理难点,从而确保环境空气污染防治攻坚战稳步推进并取得胜利.

Haze observations by simultaneous lidar and WPS in Beijing before and during APEC, 2014

We present combined Mie lidar, ozone lidar and wide-range particle spectrometer observations which were carried out in Beijing, north China during two periods—one haze period before the Asia-Pacific Economic Cooperation(APEC) meeting and one moderate pollution period during the meeting in 2014. High extinction coefficient, moderate ozone concentration and variable particle number concentration were obtained throughout the first haze observation period. The mean extinction coefficients in the two pollution periods were 0.52 and 0.23 km?1, respectively, at 532 nm. The ozone concentration during the first haze phase was more various with a higher average value of 49 ppb compared with that in the second pollution observations(32 ppb). Compared with the same metrological condition occurring at the end of October, the sharply decreased aerosol extinction coefficient and ozone concentration show the effectiveness of the emission-cutting measures implemented during APEC in November. The comparison of aerosols and ozone in different heights indicate different pollution sources and the complicated ozone process of generation and disappearance. The correlation between the scattering coefficient and particle number concentrations of various diameter depended on the ambient humidity. Especially the particle number concentration(500 nm–1 ?m) contributed most to PM2.5 concentration. The four-day back trajectories from a Hybrid Single-particle Lagrangian Integrated Trajectory(HYSPLIT) model indicate that the air masses in the lower boundary layer before and during APEC were advected from the densely populated south regions of China and the long pollution transportation passing through northern China.

Variation of temporal and spatial patterns of NO_2 in Beijing using OMI and mobile DOAS

Control policies such as "odd-and-even license plate rule" were implemented by the Chinese government to restrict traffic and suspend factory production in Beijing and neighboring cities during the Asia-Pacific Economic Cooperation summit. We use ozone monitoring instrument(OMI), mobile differential optical absorption spectroscopy(DOAS), and multi-axis differential optical absorption spectroscopy(MAX-DOAS) to measure the variation of the spatial and temporal patterns of NO2 column densities from October 24, 2014 to November 22, 2014. It is found that the NO2 column densities during the episode of control policies are significantly lower than those during other periods, and the emission flux of NO2 calculated by mobile DOAS is also lower than the results from other periods. Some daily low NO2 column densities occur with the northwest wind direction. We then compare the relationship between OMI and mobile DOAS NO2 column density observations, and the results of mobile DOAS are approximately 2.7 times larger than the OMI values. The largest discrepancy occurs in the northern part of Beijing city. In other parts, the two instruments have a better correlation coefficient(R2) of 0.61. The low NO2 column densities that occur during the episode of control policies are affected by the control policies as well as meteorological conditions.

Modes of genetic adaptations underlying functional innovations in the rumen

The rumen is the hallmark organ of ruminants and hosts a diverse ecosystem of microorganisms that facilitates efficient digestion of plant fibers.We analyzed 897 transcriptomes from three Cetartiodactyla lineages:ruminants,camels and cetaceans,as well as data from ruminant comparative genomics and functional assays to explore the genetic basis of rumen functional innovations.We identified genes with relatively high expression in the rumen,of which many appeared to be recruited from other tissues.These genes show functional enrichment in ketone body metabolism,regulation of microbial community,and epithelium absorption,which are the most prominent biological processes involved in rumen innovations.Several modes of genetic change underlying rumen functional innovations were uncovered,including coding mutations,genes newly evolved,and changes of regulatory elements.We validated that the key ketogenesis rate-limiting gene(HMGCS2)with five ruminant-specific mutations was under positive selection and exhibits higher synthesis activity than those of other mammals.Two newly evolved genes(LYZ1 and DEFB1)are resistant to Gram-positive bacteria and thereby may regulate microbial community equilibrium.Furthermore,we confirmed that the changes of regulatory elements accounted for the majority of rumen gene recruitment.These results greatly improve our understanding of rumen evolution and organ evo-devo in general.