Non-Destructive Detection and Evaluation of Heavy Metal Pollution in Tailings Reservoir

Heavy metal pollution is a negative effect generated in the process of utilizing non-ferrous mineral. Studies about heavy metal migration detection are very important. A new method for rapid detection of heavy metal migration based on ground penetrating radar (GPR) was provided. Comparative tests were studied from field to lab with GPR and X-ray fluorescence analysis (XRF). A tailings reservoir in the Xiangjiang River basin at Hunan Province was taken as experimental site. The downward transfer rule of heavy metal migration was confirmed through tests on systematically arranged survey lines and sampling points in tailings site. Results showed: 1) Through GPR image recognition, tailings reservoir had 3 layers. Reclaimed soil layer (the first layer) and tailings layer (the second layer) had a clear interface. However, tailings layer (the second layer) and subsoil layer (the third layer) had an obscure interface on radar images. It was concluded that heavy metal component had migrated downwards. 2) Chemical component analysis verified image recognition conclusions. Concentrations of As, Cd and Pb were significantly out of limit, while concentration of Cr was under limit according to analysis results on samples from different depths. 3) Pollution degree was evaluated. Downward migration was the main form of heavy metal migration in tailings site, upward migration occurred through adsorption at the same time.

Impact of the Mining Rights Allocation Process on the Sustainable Development of the Copper Mining Industry in Zambia

The limited character of minerals must be recognized in the development of mining activities, as well as the necessity to form bonds that allow mining advantages to be enjoyed long after natural resources have been consumed. Because mining activities have the potential to affect a wide variety of environmental entities and are of interest to a large range of stakeholder groups, the sector has a lot of room to improve its sustainability. According to studies, the economic advantages of copper mining operations in Zambia are not allocated equally among stakeholders in the process of granting mining rights to potential investors. This paper examines how the existing system of granting mining rights in Zambia impacts the distribution of economic gains among copper mining project stakeholders.

c-Fos expression within the L_5 spinal cord dorsal horn after spinal nerve ligation in rats Is intraplantar administration of glutamate different from intrathecal administration?

BACKGROUND： Injection of glutamate （Glu） in normal animals can cause neuronal c-Fos expression; however, whether Glu can induce spinal neuronal c-Fos expression in pain models is unclear. OBJECTIVE： To examine the effects of intraplantar and intrathecal injection of Glu on c-Fos expression in the L5 spinal cord dorsal horn Ⅰ/Ⅱ and Ⅲ/Ⅳ layers after spinal nerve ligation, and to study the effects of the N-methyI-D-aspartic acid （NMDA） receptor antagonist, D-2-amino-5-phosphonopentanoate （D-AP5）, and a selective group I mGluR antagonist, 7-hydroyiminocyclo propan[a]chromen-lacarboxylic acid ethyl ester （cpccoEt）. DESIGN, TIME AND SETTING： A randomized, controlled animal study was performed at the Department of Pharmacology, Oral Anatomy, and Neurobiology, Osaka University Graduate School of Dentistry, from December 2005 to December 2006. MATERIALS： Glu （5 μmol）, D-AP5 （50 nmot） and cpccoEt （250 nmol） were provided by Wako Pure Chemical Industries, Osaka, Japan, and diluted in saline （50 μL）. The pH of all solutions was adjusted to 7.4. METHODS： Twelve rats were randomly divided into sham operation （n = 6） and spinal nerve ligation （SNL; n = 6） groups for behavioral assessments of neuropathic pain after ligation surgery of the left L5-6 nerve segment. Another 60 rats were randomly divided into sham operation, SNL, saline-intraplantar, saline-intrathecal, Glu-intraplantar, Glu-intrathecal, D-AP5-intrathecal, Glu-D-AP5-intrathecal, cpccoEt-intrathecal, and Glu-cpccoEt-intrathecal groups, with 6 rats in each group. All groups except sham operation group received a similar SNL. On day 14, rats received a 50-μL injection of saline, Glu, D-AP5, and/or cpccoEt into the left intraplantar or intrathecal L5-4 segments. MAIN OUTCOME MEASURES： The number of c-Fos positive neurons in both Ⅰ/Ⅱ and Ⅲ/Ⅳ spinal layers at L6 was observed using immunohistochemistry 2 hours after administration. RESULTS： （1） SNL increased the level of c-Fos expression in two sides of the spinal cord, particularly on Ⅲ/Ⅳ spinal layers of the ligated side. （2） Intraplantar or intrathecal administration of saline significantly increased the c-Fos labeled neurons in Ⅰ/Ⅱ spinal layers of the ligated side, compared with SNL alone （P 〈 0.01）. （3） Intraplantar Glu （5 μmol） increased the number of c-Fos positive neurons in Ⅰ/Ⅱ spinal layers compared with intraplantar saline （P〈 0.01）. （4） The number of c-Fos neurons in Ⅰ/Ⅱ spinal layers on both the ipsilateral and contralateral side after intraplantar Glu was lower than intrathecal Glu （P〈 0.01）, with a 3-fold higher induction by intrathecal Glu. （5） Co-administration of D-AP5 or cpccoEt reduced the effects of intrathecal Glu （P 〈 0.01）. CONCLUSION： Intrathecal Glu increases c-Fos expression more than intraplantar Glu. Antagonists of NMDA and group I mGluRs block this effect.

Nanoindentation Study on Mechanical Properties of Nano-SiO2/Dental Resin Composites

The micro/nano-scale indentation tests were performed to explore the performance of bisphenol-α-glycidyl methacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) dental resin composites. The effect of the filling content of nano-SiO2 particles on the mechanical properties of the dental composites was studied as well. The experimental results showed that the incorporation of the nano-SiO2 particles at low concentrations (up to 10 wt.%) can apparently increase the hardness and elastic modulus of the dental rein composites. The plasticity index indicates a best elastic recovery capability at a proper amount (4 wt.%) of the nanoparticles. Combined with the infrared spectrum, the mechanical enhancement mechanisms of the dental resin composites were analyzed.

紫外引发聚合联合原位氧化聚合制备光热响应性软体驱动水凝胶

针对高等学校高分子科学实验教学项目缺乏时代创新性的现状,提出了将两种聚合策略联用的手段,制备具有光控响应特性的聚合物基软体驱动水凝胶材料,并对其光热驱动行为进行表征,以拓展学生对高分子材料在仿生智能应用领域的认知。本实验首先利用紫外引发聚合的方法制备具有温度响应特性的聚N-异丙基丙烯酰胺(PNIPAM)水凝胶,并进一步联合导电聚合物的原位氧化聚合策略,在PNIPAM水凝胶的内部原位生长具有光热效应的导电聚合物材料,从而制备得到具有光热响应特性的软体驱动复合水凝胶材料,并最终通过近红外光照射的方式,探究所制备光热驱动水凝胶的智能响应驱动性能。本实验立足于当代前沿研究热点,内容既涵盖利用基础聚合方法制备高分子材料,又包含功能性聚合物材料的性能表征,不仅可以夯实学生对高分子聚合方法的理解,还可以拓展学生对功能性高分子材料研究前沿的认知,将有利于提高学生的培养质量。

Exploring the Path of Cultivating College Students’ Personal Morality in Ideological and Political Theory Courses

Based on the demand of social development for people with both ability and political integrity,it has been acknowledged that some college students have a problem,where their personal morality does not match their professional knowledge.In short,these students have rich and profound professional knowledge,but their personal morality is lacking.Therefore,the attention to such a problem is called for.This paper analyzes the path of cultivating college students’personal morality in ideological and political theory courses in the new era,combs and expounds the occurrence mechanism between college students’personal morality and ideological and political theory courses in the new era,improves the effectiveness of moral cultivation in ideological and political theory courses from four dimensions-teaching materials,teachers,teaching methods,and evaluation,as well as gives full play to the moral cultivation function of ideological and political theory courses in colleges and universities.

Three-dimensionally ordered, ultrathin graphitic-carbon frameworks with cage-like mesoporosity for highly stable Li-S batteries

Mesoporous carbons have been widely utilized as the sulfur host for lithium-sulfur （Li-S） batteries. The ability to engineer the porosity, wall thickness, and graphitization degree of the carbon host is essential for addressing issues that hamper commercialization of Li-S batteries, such as fast capacity decay and poor high-rate performance. In this work, highly ordered, ultrathin mesoporous graphitic-carbon frameworks （MGFs） having unique cage-like mesoporosity, derived from self-assembled Fe304 nanoparticle superlattices, are demonstrated to be an excellent host for encapsulating sulfur. The resulting S@MGFs exhibit high specific capacity （1,446 mAh.g-1 at 0.15 C）, good rate capability （430 mAh.g-1 at 6 C）, and exceptional cycling stability （-0.049% capacity decay per cycle at 1 C） when used as Li-S cathodes. The superior electrochemical performance of the S@MGFs is attributed to the many unique and advantageous structural features of MGFs. In addition to the interconnected, ultrathin graphitic-carbon framework that ensures rapid electron and lithium-ion transport, the microporous openings between adjacent mesopores efficiently suppress the diffusion of polysulfides, leading to improved capacity retention even at high current densities.

Immunomodulatory and Antiviral Therapy Improved Functional Cure Rate in CHB Patients with High HBsAg Level Experienced NA

Background and Aims:A functional cure,or hepatitis B virus(HBV)surface antigen(HBsAg)loss,is difficult to achieve in patients with hepatitis B virus e antigen(HBeAg)-positive chronic hepatitis B.The HBV vaccine and granulocyte-macrophage colony-stimulating factor(GM-CSF)have been reported to help reduce HBsAg levels and promote HBsAg loss.In this prospective randomized trial,we evaluated HBsAg loss in patients receiving pegylated interferon α2b(PEGIFN-α2b)and tenofovir disoproxil fumarate(TDF),with and without GM-CSF and HBV vaccination.Methods:A total of 287 patients with HBeAg positive chronic hepati-tis B and seroconversion after nucleot(s)ide analog treat-ment were assigned randomly to three treatment groups for 48 weeks,TDF alone(control),PEGIFN-α2b+TDF,and PEGIFN-α2b+TDF+GM-CSF+HBV vaccine.The prima-ry endpoints were the proportions of patients with HBsAg loss and seroconversion at 48 and 72 weeks.Resu/ts:The cumulative HBsAg loss rates in the control,PEGIFN-α2b+TDF,and PEGIFN-α2b+TDF+GM-CSF+HBV vaccine groups at week 48 were 0.0%,28.3%,and 41.1%,respec-tively.The cumulative HBsAg seroconversion rates in these groups at week 48 were 0.0%,21.7%,and 33.9%,respec-tively.Multivariate regression analysis showed that GM-CSF use plus HBV vaccination was significantly associated with HBsAg loss(p=0.017)and seroconversion(p=0.030).Con-clusions:In patients with HBeAg-positive chronic hepatitis B and seroconversion after nucleot(s)ide analog treatment,immunomodulatory/antiviral treatment regimens effective-ly improved HBsAg loss,and the regimen including GM-CSF and HBV vaccination was most effective.

Designed synthesis of ordered mesoporous graphene spheres from colloidal nanocrystals and their application as a platform for high-performance lithium-ion battery composite electrodes

Three-dimensional （3D） graphene has recently attracted enormous attention for electrochemical energy storage applications. However, current methods suffer from an inability to simultaneously control and engineer the porosity and morphology of the graphene frameworks. Here, we report the designed synthesis of ordered mesoporous graphene spheres （OMGSs） by transformation of self-assembled Fe3O4 nanocrystal superlattices. The resultant OMGSs have an ultrathin framework comprising few-layered graphene, with highly ordered and interconnected mesoporosity and a high surface area. These advantageous structural and textural features, in combination with the excellent electrical conductivity of the graphitic frameworks, render the OMGSs an ideal and general platform for creating hybrid materials that are well suited for use as composite electrodes in lithium-ion batteries （LIBs）. As a proof-of-concept demonstration, SnO2 and GeO2 nanoparticles are incorporated into the OMGSs to afford SnO2@OMGSs and GeO2@OMGSs, respectively, both of which exhibit outstanding lithium storage properties when used as LIB anodes.

局部平稳时间序列时变单指标变系数模型及统计推断

本文基于局部平稳时间序列数据的特征提出一个新的半参数模型—时变单指标变系数模型.本文采用二步估计的思想给出模型中参数和非参数系数函数的估计方法,并研究这些估计量的渐近性质,包括相合性和渐近正态性.进一步,为了判别模型中的连接函数是否具有时变性质,本文提出一种假设检验方法,构造相应的检验统计量并证明它的渐近性质.最后,通过模拟和实例展示本文所提估计和检验方法是有效和切实可行的.

High performance lithium-sulfur batteries by facilely coating a conductive carbon nanotube or graphene layer

Lithium sulfur(Li-S) batteries are regarded as promising candidates for next-generation rechargeable batteries. However, the insulation characteristic of sulfur and severe polysulfide dissolution hindered their development. We presented a facile approach to fabricate Li-S batteries by coating commercial carbon nanotube or graphene slurries on normal sulfur cathode electrode to construct a dual-layer cathode electrode. The conductive CNT or graphene layer could not only improve the conductivity of sulfur cathode, but also suppress the polysulfide diffusion. The CNT@S cathode delivered a high reversible capacity of 740 mAh/g over 300 cycles at 1 C and 870 mAh/g over 100 cycles at 0.2 C. Furthermore, this strategy could be realized on the commercial product line of lithium-ion batteries, which made it possible to large-scale produce Li-S batteries.

A group adaptive elastic-net approach for variable selection in high-dimensional linear regression

In practice, predictors possess grouping structures spontaneously. Incorporation of such useful information can improve statistical modeling and inference. In addition, the high-dimensionality often leads to the collinearity problem. The elastic net is an ideal method which is inclined to reflect a grouping effect. In this paper, we consider the problem of group selection and estimation in the sparse linear regression model in which predictors can be grouped. We investigate a group adaptive elastic-net and derive oracle inequalities and model consistency for the cases where group number is larger than the sample size. Oracle property is addressed for the case of the fixed group number. We revise the locally approximated coordinate descent algorithm to make our computation. Simulation and real data studies indicate that the group adaptive elastic-net is an alternative and competitive method for model selection of high-dimensional problems for the cases of group number being larger than the sample size.

Free-space beam shaping and steering based on a silicon optical phased array

In this study,we present a method for free-space beam shaping and steering based on a silicon optical phased array,which addresses the theoretical limitation of traditional bulk optics.We theoretically analyze the beam propagation properties with changes in the applied phase.Different beam profiles can be shaped by varying the phase combination,while a high-order quasi-Bessel beam can be generated with a cubic change to the phase modulation.The simulated results are validated further experimentally,and they match one another well.Beam steering can be achieved with a field of view as large as 140°,which has potential benefits for practical applications.The presented method is expected to have broad application prospects for optical communications,free-space optical interconnects,and light detection and ranging.

Thermal and pH Dual Responsive Copolymer and Silver Nanoparticle Composite for Catalytic Application

N-Isopropylacrylamide and vinyl imidazole copolymer,P(NIPAM-co-VI),was synthesized by free radical emulsion polymerization.Then,the copolymer and silver nanoparticle composite,P(NIPAM-co-VI)-Ag,was pre-pared by in situ reduction of AgNO3 with NaBH4.Due to the coexistence of thermal-responsive PNIPAM and pH-responsive PVI,P(NIPAM-co-VI)and P(NIPAM-co-VI)-Ag exhibited both thermal and pH responsibility,their size would change while altering the temperature or pH of the circumvent.Their thermal and pH dual responsive properties were studied by dynamic light scattering(DLS).P(NIPAM-co-VI)-Ag could be stably dispersed in water at a pH range from 3.0 to 9.3,which is favorable to use P(NIPAM-co-VI)-Ag as a catalyst in the reduction reaction of p-nitrophenol.The reaction rate constant(kapp)increased with the decrease of pH or the increase of VI content in the copolymer.

Typical hemophagocytic syndrome associated with cytomegalovirus infection in an immunocompetent patient: a case report and literature review

Cytomegalovirus(CMV)infection is currently prevalent in populations throughout the world,and 56%-94%of the global population is seropositive for CMV.CMV infection mainly affects immunocompromised hosts.In these cases,it can cause significant symptoms,tissue-invasive disease,and many sequelae including death(Dioverti and Razonable,2016).The vast majority of healthy adults with CMV infection experience an asymptomatic course;when symptomatic,it manifests as a mononucleosis-like syndrome in approximately 10%of patients(Sridhar et al.,2018).