Enhancing capacitive deionization performance and cyclic stability of nitrogen-doped activated carbon by the electro-oxidation of anode materials

Electrode materials with high desalination capacity and long-term cyclic stability are the focus of capacitive deionization(CDI) community. Understanding the causes of performance decay in traditional carbons is crucial to design a high-performance material. Based on this, here, nitrogen-doped activated carbon(NAC) was prepared by pyrolyzing the blend of activated carbon powder(ACP) and melamine for the positive electrode of asymmetric CDI. By comparing the indicators changes such as conductivity, salt adsorption capacity, pH, and charge efficiency of the symmetrical ACP-ACP device to the asymmetric ACP-NAC device under different CDI cycles, as well as the changes of the electrochemical properties of anode and cathode materials after long-term operation, the reasons for the decline of the stability of the CDI performance were revealed. It was found that the carboxyl functional groups generated by the electro-oxidation of anode carbon materials make the anode zero-charge potential(E_(pzc)) shift positively,which results in the uneven distribution of potential windows of CDI units and affects the adsorption capacity. Furthermore, by understanding the electron density on C atoms surrounding the N atoms, we attribute the increased cyclic stability to the enhanced negativity of the charge of carbon atoms adjacent to quaternary-N and pyridinic-oxide-N.

Recent Progress of Surface Passivation Molecules for Perovskite Solar Cell Applications

Due to the solution processable nature,the prepared perovskite films are polycrystalline with considerable number of defects.These defects,especially defects at interface accelerate the carrier recombination and reduce the carrier collection.Besides,the surface defects also affect the long-term stability of the perovskite solar cells(PVSCs).To solve this problem,surface passivation molecules are introduced at selective interface(the interface between perovskite and carrier selective layer).This review summarizes recent progress of small molecules used in PVSCs.Firstly,different types of defect states in perovskite films are introduced and their effects on device performance are discussed.Subsequently,surface passivation molecules are divided into four categories,and the interaction between the functional groups of the surface passivation molecules and selective defect states in perovskite films are highlighted.Finally,we look into the prospects and challenges in design noble small molecules for PVSCs applications.

Life-history dependent relationships between plasma alkaline phosphatase activity and body condition in male Eurasian Tree Sparrows

Background: In temperate-breeding birds, individuals must adjust their physiological states from one life-history stage to another in response to changing conditions to maximize ecological fitness. Previous evidences have shown that body mass, size-corrected mass(SCM), and hematocrit(Hct) could be used as estimates of the energetic state of individuals to illustrate life-history trade-offs and individual quality in field physiology. Plasma alkaline phosphatase(ALP) plays critical roles in regulating the metabolism of energy but very limited information is known on its link with body mass or Hct.Methods: We determined the changes of plasma ALP levels in both early breeding and wintering stages of male Eurasian Tree Sparrows(Passer montanus), and examined the relationships between ALP and body mass, SCM, and Hct of the birds.Results: Our study showed that(1) in male Eurasian Tree Sparrows, body mass did not vary with life-history stage but plasma ALP activity significantly increased in the wintering stage compared to the breeding stage;(2) ALP activity was not correlated with individual body mass but was positively correlated with individual SCM and Hct. Such positive correlations, however, only occurred in the wintering but not in the breeding stages.Conclusions: Our results suggest that plasma ALP activities in free-living birds can be used as one of the indicators o body condition or nutritional status for analyzing individual variation in the wintering but not in the breeding stages. The life-history dependent relationships between plasma ALP activity and body condition may contribute to our better understanding of the trade-off between individual survival and reproduction in free-living animals.

Data Discrimination in Fault-Prone Sensor Networks

While sensor networks have been used in various applications because of the automatic sensing capability and ad-hoc organization of sensor nodes, the fault-prone characteristic of sensor networks has challenged the event detection and the anomaly detection which, to some extent, have neglected the importance of discriminating events and errors. Considering data uncertainty, in this article, we present the problem of data discrimination in fault-prone sensor networks, analyze the similarities and the differences between events and errors, and design a multi-level systematic discrimination framework. In each step, the framework filters erroneous data from the raw data and marks potential event samples for the next-step processing. The raw data set D is finally partitioned into three subsets, Devent, Derror and Dordinary. Both the scenario-based simulations and the experiments on real-sensed data are carried out. The statistical results of various discrimination metrics demonstrate high distinction ratio as well as the robustness in different cases of the network.

Fast Cycle Structure Detection for Power Grids Based on Graph Computing

The cycle structure in a power grid may lower the stability of the network;thus,it is of great significance to accu-rately and timely detect cycles in power grid networks.However,detecting possible cycles in a large-scale network can be highly time consuming and computationally intensive.In addition,since the power grid's topology changes over time,cycles can appear and disappear,and it can be difficult to monitor them in real time.In traditional computing systems,cycle detection requires considerable computational resources,making real-time cycle detection in large-scale power grids an impossible task.Graph computing has shown excellent performance in many areas and has solved many practical graph-related problems,such as power flow calculation and state estimation.In this article,a cycle detection method,the Paton method,is implemented and optimized on a graph computing platform.Two cases are used to test its performance in an actual power grid topology scenario.The results show that the graph computing-based Paton method reduces the time consumption by at least 60%compared to that of other methods.

腾冲嗜热厌氧菌丙氨酸消旋酶底物通道氨基酸位点的功能

【目的】通过定点突变探究腾冲嗜热厌氧菌MB4中生物合成型丙氨酸消旋酶Tt Alr底物通道内氨基酸位点A172和S173的功能。【方法】利用定点突变PCR技术构建突变体,通过亲和层析法纯化酶蛋白,采用D-氨基酸氧化酶偶联法检测各突变蛋白的活性及其稳定性。【结果】通过定点突变PCR成功得到8个突变体,酶学特性分析发现,A172位点突变为丝氨酸(S)后酶蛋白的相对活性有所提升,但含有该位点突变的酶蛋白稳定性均大幅下降;S173位点突变为天门冬氨酸(D)后导致突变体蛋白的最适反应温度提升了15°C,半衰期大幅延长,但相对活性明显下降。【结论】丙氨酸消旋酶Tt Alr底物通道内A172和S173位点均是影响酶蛋白催化活性和稳定性的关键位点。

橡椀单宁对Q235碳钢在0.5 mol/L HCl溶液中的缓蚀作用研究

采用失重实验、极化曲线、电化学阻抗、扫描电镜及分子模拟等方法,研究了橡椀单宁对Q235碳钢在0.5mol/L HCl溶液中的缓蚀性能,并探讨了其缓蚀机理。结果表明,当橡椀单宁浓度为6g/L,橡椀单宁对Q235碳钢的缓蚀率可达96.46%。电化学实验研究表明,加入橡椀单宁后,腐蚀电流减小接近1个数量级,电荷转移电阻增大近7倍。扫描电镜观察可见,橡椀单宁在碳钢表面形成一层保护膜。吸附热力学分析表明,橡椀单宁在碳钢表面发生物理和化学混合型吸附作用,且符合Langmuir等温吸附方程。分子模拟研究表明,橡椀单宁以平面的形式稳定吸附在碳钢表面。

Analyzing and forecasting CO2 emission reduction in China＇s steel industry

Recent measures of carbon dioxide emissions from the steel industry of China have indicated a high rate of total CO2 emissions from the industry, even compared to the rest of the world. So, CO2 emission reduction in China＇s steel industry was analyzed, coupling the whole process and scenarios analysis. First, assuming that all available advanced technologies are almost adopted, this study puts forward some key potential-sectors and explores an optimal technical route for reducing CO2 emissions from the Chinese steel industry based on whole process analysis. The results show that in the stages of coking, sintering, and iron making, greater potential for reducing emissions would be fulfilled by taking some technological measures. If only would above well-developed technolo- gies be fulfill, the CO2 emissions from 5 industry production stages would be reduced substantially, and CO2 emissions per ton of steel could be decreased to 1.24 （ton/ton-steel） by 2020. At the same time, the scenarios analysis indicates that if mature carbon-reducing technol- ogies are adopted, and if the difference between steel output growth rate and the GDP growth rate could be controlled below 3%, CO2 emissions from China＇s steel industry would approach the goal of reducing CO2 emissions per GDP unit by 40%-45% of the 2005 level by 2020. This indicates that the focus of carbon dioxide emissions reduction in China lies in policy adjustments in order to enhance technological application, and lies in reasonably controlling the pace of growth of GDP and steel output.

Identification and genetic characterization of Contracaecum sp.(Nematoda:Anisakidae)from China

Contracaecum species are economically important fish-borne larval nematodes with zoonotic significance.In June 2019,more than 100 piscivorous birds died in their habitats close to the Wild Duck Lake,located in Yanqing,northwest of Beijing,China.Post-mortem examination of Black Night Herons(Nycticorax)revealed the presence of numerous anisakid nematodes in the proventriculus.Recovered nematodes were identified as Contracaecum sp.based on morphological description.Phylogenetic analysis of the mitochondrial(mt)genome and the ITS gene showed that sequences of Contracaecum sp.Beijing isolates were grouped into a new individual cluster.Furthermore,the parasite was successfully isolated from fresh dead birds,feces of piscivorous birds,and fish and prevalence ranged from 8.0%to 81.8%.Consequently,our study demonstrated Contracaecum sp.infections in different sources from China,which might constitute a threat to wildlife,aquaculture,and public health.

Application of microneedle-based vaccines in biosecurity

Countries must have strong early warning,detection,and response capabilities in the face of the risks and challenges posed by major infectious diseases and bioterrorism threats.Vaccination is one of the most effective means for countries to maintain biosecurity and respond to bioterrorism attacks.Microneedles are emerging as a potential vaccine delivery method with minimal pain,no bleeding,and the ability to be self-administered,doing away with the need for professional health care workers.This last advantage,particularly if combined with room temperature preservation,could have an important role in improving national biosecurity through large-scale,rapid deployment of a biological vaccine.In this review,we summarized the research status of microneedles,including the types,materials,and production technologies of microneedles.Recent progress regarding microneedles in the field of biosecurity is introduced and challenges in its future application are discussed.

A photoactivatable and phenylboronic acid-functionalized nanoassembly for combating multidrug-resistant gram-negative bacteria and their biofilms

Background:Multidrug-resistant(MDR)gram-negative bacteria-related infectious diseases have caused an increase in the public health burden and mortality.Moreover,the formation of biofilms makes these bacteria difficult to control.Therefore,developing novel interventions to combat MDR gram-negative bacteria and their biofilms-related infections are urgently needed.The purpose of this study was to develop a multifunctional nanoassembly(IRNB)based on IR-780 and N,N-di-sec-butyl-N,N-dinitroso-1,4-phenylenediamine(BNN6)for synergistic effect on the infected wounds and subcutaneous abscesses caused by gram-negative bacteria.Methods:The characterization and bacteria-targeting ability of IRNB were investigated.The bac-tericidal efficacy of IRNB against gram-negative bacteria and their biofilms was demonstrated by crystal violet staining assay,plate counting method and live/dead staining in vitro.The antibacterial efficiency of IRNB was examined on a subcutaneous abscess and cutaneous infected wound model in vivo.A cell counting kit-8 assay,Calcein/PI cytotoxicity assay,hemolysis assay and intravenous injection assay were performed to detect the biocompatibility of IRNB in vitro and in vivo.Results:Herein,we successfully developed a multifunctional nanoassembly IRNB based on IR-780 and BNN6 for synergistic photothermal therapy(PTT),photodynamic therapy(PDT)and nitric oxide(NO)effect triggered by an 808 nm laser.This nanoassembly could accumulate specifically at the infected sites of MDR gram-negative bacteria and their biofilms via the covalent coupling effect.Upon irradiation with an 808 nm laser,IRNB was activated and produced both reactive oxygen species(ROS)and hyperthermia.The local hyperthermia could induce NO generation,which further reacted with ROS to generate ONOO−,leading to the enhancement of bactericidal efficacy.Furthermore,NO and ONOO−could disrupt the cell membrane,which converts bacteria to an extremely susceptible state and further enhances the photothermal effect.In this study,IRNB showed a superior photothermal-photodynamic-chemo(NO)synergistic therapeutic effect on the infected wounds and subcutaneous abscesses caused by gram-negative bacteria.This resulted in effective control of associated infections,relief of inflammation,promotion of re-epithelization and collagen deposition,and regulation of angiogenesis during wound healing.Moreover,IRNB exhibited excellent biocompatibility,both in vitro and in vivo.Conclusions:The present research suggests that IRNB can be considered a promising alternative for treating infections caused by MDR gram-negative bacteria and their biofilms.