寒门子弟的高等教育经历研究——寒门幸运儿和双重贫困生的异质性视角

寒门子弟的高等教育经历表现话题长期存在二元对立的观点。本研究追溯高中教育经历,并分析其与高等教育环境间的连续性,丰富寒门背景对大学生综合表现的影响机制,以示范性普通高中机会获得将寒门子弟区分为寒门幸运儿和双重贫困生两类群体,同时与非寒门子弟在大学期间的学业成就、人际交往和毕业预期去向等高等教育经历方面进行全面比较。结果显示,寒门幸运儿和双重贫困生的学业成绩排名均显著优于非寒门大学生;寒门幸运儿有着不亚于非寒门大学生的人际交往表现,能尽快适应融入高校生活,而双重贫困生对人际交往更可能感到不适应,人际交往能力水平也更低;寒门幸运儿与非寒门大学生的毕业规划类似,即毕业后更可能继续深造,而双重贫困生则更可能直接就业。本研究的结论验证了寒门大学生内部的异质性,并肯定了通过家庭之外的文化资本补偿对寒门子弟突破家庭资本劣势的重要意义。

High efficiency and broad bandwidth terahertz vortex beam generation based on ultra-thin transmission Pancharatnam-Berry metasurfaces

The terahertz(THz)vortex beam generators are designed and theoretically investigated based on single-layer ultra-thin transmission metasurfaces.Noncontinuous phase changes of metasurfaces are obtained by utilizing Pancharatnam-Berry phase elements,which possess different rotation angles and are arranged on two concentric rings centered on the origin.The circularly polarized incident THz beam could be turned into a cross-polarization transmission wave,and the orbital angular momentum(OAM)varies in value by lh.The l values change from±1 to±5,and the maximal cross-polarization conversion efficiency that could be achieved is 23%,which nearly reaches the theoretical limit of a single-layer structure.The frequency range of the designed vortex generator is from 1.2 THz to 1.9 THz,and the generated THz vortex beam could keep a high fidelity in the operating bandwidth.The propagation behavior of the emerged THz vortex beam is analyzed in detail.Our work offers a novel way of designing ultra-thin and single-layer vortex beam generators,which have low process complexity,high conversion efficiency and broad bandwidth.

TAZ促进胃癌中血管生成及相关机制的研究

目的:探究Hippo通路关键效应分子TAZ在胃癌组织中的表达及其在胃癌血管生成中的作用。方法:通过免疫组织化学法分析150例胃癌组织标本中TAZ和β-catenin的表达情况;将TAZ过表达质粒及干扰质粒通过慢病毒分别转染至胃癌细胞系MGC803和MKN28中,通过细胞功能实验检测内皮细胞成管、增殖及迁移能力;使用Western blot法检测转染后的胃癌细胞中TAZ及β-catenin的表达情况;采用酶联免疫吸附试验(ELISA)检测TAZ转染后血管内皮生长因子(vascular endothelial growth factor,VEGF)蛋白表达的变化。结果:免疫组织化学法结果显示150例胃癌组织中,TAZ阳性表达64例(阳性率43%),主要定位于细胞核,其表达与肿瘤分级、TNM分期、转移及微血管密度(microvessel density,MVD)有关(P<0.05)。此外,在TAZ阳性组中β-catenin阳性表达率为67.2%,明显高于TAZ阴性组,TAZ的表达与β-catenin呈正相关。在MKN28细胞系中上调TAZ的表达,与HUVEC细胞共培养后增强了内皮细胞增殖及管道形成能力,此外还通过促进β-catenin的表达,增强了内皮细胞的迁移能力;相反,在MGC803细胞系中下调TAZ的表达,与HUVEC共培养后减弱了内皮细胞增殖和管道形成能力,此外还通过降低β-catenin的表达,抑制了内皮细胞的迁移能力。结论:胃癌细胞TAZ的高表达可能通过促进β-catenin和VEGF的表达,进而增强胃癌血管生成能力。

教师培训能缩小城乡学生的学业差距吗?——来自CEPS基线数据的经验证据

基于中国教育追踪调查基线数据,探究教师培训与城乡学生成绩的关系及对城乡学生成绩差距的影响。结果表明:第一,城乡学生间存在显著的学业成绩差距,且高分位点上、语言类学科中差距更大。第二,无条件分位数回归结果显示,教师培训能够提高城市不同学业水平和农村中等及以上学业水平学生的成绩,但无法提高农村中等偏下学业水平学生的成绩;此外,教师培训的影响效应在城市地区整体明显高于农村地区。第三,不同分位点的Oaxaca-Blinder分解发现,教师培训的禀赋效应和系数效应都是造成学生成绩城乡差距的重要原因,但是二者的相对大小因年级和学业成绩分布的位置差异而有所不同。因此,增加农村教师的培训机会、提高农村教师的培训质量、改善农村学生的资源转换率对于缩小学生成绩的城乡差距有着重要的现实意义。

Advancement in separation materials for blood purification therapy

Blood purification refers to the extra corporeal therapies of removing potentially toxic substances, in which blood is circulated through an adsorption system loading separation materials. High-efficient inexpensive separation materials are critical to success. In this review, separation materials such as polymers and nanomaterials are summarized and compared. Combining the advantages of the adsorptive membranes and nanomaterials, organic–inorganic hybrid/blend membranes have been developed explosively. These hybrid/blend membranes have both the characteristics of high permeability, easy fabrication, good biocompatibility of adsorptive membranes, and characteristics of fast adsorption rate and high adsorption capacity of nanomaterials. The preparation and modification methodology of the separation materials is reviewed. For affinity separation materials, the relationship of ligand chemistry, ligand density and pores of the matrix is discussed. This paper also summarizes some interesting applications in separation materials for removal of bilirubin, endotoxin, toxic metal ions, cytokine, etc.

Correlation between X-ray cross-complementing group 1 polymorphisms and the onset risk of glioma A meta-analysis

OBJECTIVE： To evaluate the association of X-ray cross-complementing group 1 （XRCC1） Arg399GIn, Arg194Trp and Arg280His polymorphisms with the risk of glioma. DATA SOURCES： A systematic literature search of papers published from January 2000 to August 2012 in PubMed, Embase, China National Knowledge Infrastructure database, and Wanfang da- tabase was performed. The key words used were ＂glioma＂, ＂polymorphism＂, and ＂XRCC1 or X-ray repair cross-complementing group 1＂. References cited in the retrieved articles were screened manually to identify additional eligible studies. STUDY SELECTION： Studies were identified according to the following inclusion criteria： case-control design was based on unrelated individuals; and genotype frequency was available to estimate an odds ratio （OR） and 95% confidence interval （CI）. Meta-analysis was performed for the selected studies after strict screening. Dominant and recessive genetic models were used and the relationship between homozygous mutant genotype frequencies and mutant gene frequency and glioma incidence was investigated. We chose the fixed or random effect model according to the heterogeneity to calculate OR and 95%CI, and sensitivity analyses were conducted. Publication bias was examined using the inverted funnel plot and the Egger＇s test using Stata 12.0 software. MAIN OUTCOME MEASURES： Association of XRCC1 Arg399GIn, Arg194Trp, and Arg280His polymorphisms with the risk of glioma, and subgroup analyses were performed according to differ- ent ethnicities of the subjects.RESULTS： Twelve articles were included in the meta-analysis. Eleven of the articles were concerned with the Arg399GIn polymorphism and glioma onset risk. Significantly increased glioma risks were found only in the dominant model （Gin/Gin ＋ GIn/Arg versus Arg/Arg： OR = 1.26, 95%CI= 1.03-1.54, P = 0.02）. In the subgroup analysis by ethnicity, significantly increased risk was found in Asian subjects in the recessive （OR = 1.46, 95%CI= 1.04-2.45, P = 0.03） and dominant models （OR = 1.40, 95%CI= 1.10-1.78, P = 0.007）, and homozygote contrast （OR = 1.69, 95%CI= 1.17-2.45, P = 0.005）, but not in Caucasian sub- jects. For association of the Arg194Trp （eight studies） and Arg280His （four studies） polymorphisms with glioma risk, the meta-analysis did not reveal a significant effect in the allele contrast, the recessive genetic model, the dominant genetic model, or homozygote contrast. CONCLUSION： The XRCC1 Arg399GIn polymorphism may be a biomarker of glioma susceptibility, espe- cially in Asian populations. The Arg194Trp and Arg280His polymorphisms were not associated with overall glioma risk.

Broadband and high efficiency terahertz metasurfaces for anomalous refraction and vortex beam generation

The applications of metasurfaces are currently a highly active research field due to their extraordinary ability to manipulate electromagnetic waves. The ultra-thin characteristics of metasurfaces allow the miniaturization and integration of metasurface devices. However, these devices work typically under a low efficiency and narrow bandwidth condition. In this work, we design eight multilayered unit cells with similar amplitudes and a phase interval of π/4, which convert the polarization states of the terahertz(THz) waves between two orthogonal directions. The average cross-polarized transmission amplitudes of these cells are all around 0.9 in an ultra-broad frequency range from 0.5 THz to 1.4 THz. Furthermore,unit cells are used to construct both an ultra-thin anomalous refraction metalens and a vortex phase plate. Our simulation results show that the anomalous refraction for the transmitted linear polarization component is comparable to the theoretical prediction, and the maximum error is determined to be below 4.8%. The vortex phase plate can also generate an ideal terahertz vortex beam with a mode purity of 90% and more. The distributions of longitudinal electric field, intensity, and phase illustrate that the generated vortex beam has excellent propagation characteristics and a weak divergence. Simulations of the two types of metasurface devices, based on the eight unit cells, exhibit very high efficiencies in a wide bandwidth. Our research will assist in the improvement in the practical applications of metasurfaces. It also provides a reference for the design of high efficiency and broadband devices that are applied to other frequency ranges.

NSUN2-mediated mRNA m^(5)C Modification Regulates the Progression of Hepatocellular Carcinoma

RNA modifications affect many biological processes and physiological diseases.The 5-methylcytosine(m^(5)C)modification regulates the progression of multiple tumors.However,its characteristics and functions in hepatocellular carcinoma(HCC)remain largely unknown.Here,we found that HCC tissues had a higher m^(5)C methylation level than the adjacent normal tissues.Transcriptome analysis revealed that the hypermethylated genes mainly participated in the phosphokinase signaling pathways,such as the Ras and PI3K-Akt pathways.The m^(5)C methyltransferase NSUN2 was highly expressed in HCC tissues.Interestingly,the expression of many genes was positively correlated with the expression of NSUN2,including GRB2,RNF115,AATF,ADAM15,RTN3,and HDGF.Real-time PCR assays further revealed that the expression of the mRNAs of GRB2,RNF115,and AATF decreased significantly with the down-regulation of NSUN2 expression in HCC cells.Furthermore,NSUN2 could regulate the cellular sensitivity of HCC cells to sorafenib via modulating the Ras signaling pathway.Moreover,knocking down NSUN2 caused cell cycle arrest.Taken together,our study demonstrates the vital role of NSUN2 in the progression of HCC.

A Visionary Show

Seduction. Distinction. Relax. Pulsation. These are the 'style universes' on display at Première Vision, heralded as 'The World’s Premiere Fabric Show.' Started more than 35 years ago by 15 French weavers, Première Vision has expanded beyond

Research on Problems and Strategies of"Learning"from the Perspective of Physical Education Curriculum

Using literature review,questionnaire survey,mathematical statistics and other research methods,combined with the previous research results of the research team,systematically sort out the problems of"learning"in the"learning,training,competition,and use"physical education curriculum,and how to solve the problems.The strategic research of the Chinese Academy of Sciences aims to promote the scientificization of"learning"in the teaching of physical education courses,thereby improving the quality and efficiency of physical education courses.

The Musings ofa Free Spirit

Dominic Johnson-Hill has never been one to follow rules. At an age most teenagers enter college and start on the path to adulthood, Johnson-Hill left his native Britain to travel the world. For three years he moved

Zinc-finger protein 382 antagonises CDC25A and ZEB1 signaling pathway in breast cancer

Our previous studies found that Zinc-finger protein 382(ZNF382)played as a tumor suppressor gene in esophageal and gastric cancers,and a positive correlation between the high expression of ZNF382 and better outcome in breast cancer patients.However,the biological roles and mechanisms of ZNF382 in breast cancer remains unclear.We detected ZNF382 expression by reverse-transcription PCR(RT-PCR)and real-time quantitative PCR(qRT-PCR)in breast cancer cells and tissues,and explored the impacts and mechanisms of ectopic ZNF382 expression in breast cancer cells in vitro and in vivo,respectively.Our results revealed that ZNF382 was significantly down-regulated in breast cancer tissues compared with adjacent non-cancer tissues.Restoration of ZNF382 expression in silenced breast cancer cells not only inhibited tumor cell colony formation,viability,migration and invasion,and epithelial-mesenchymal-transition(EMT),but also induced apoptosis and G0/G1 arrest.In conclusion,ZNF382 could induce G0/G1 cell cycle arrest through inhibiting CDC25A signaling,and,inhibit cell migration,invasion and EMT by antagonizing ZEB1 signaling in breast cancer cells.

多氯联苯促进毛白杨不定根分化的效应

多氯联苯是一种典型的持久性有机污染物。研究表明多氯联苯具有毒物兴奋效应,但其影响植物生长发育的机制尚不清楚。以毛白杨(Populous tomentosa)组培苗为材料,探讨3mg·L^-1Aroclor1254对不定根分化、植物激素水平、与生长素相关的P009g125900、P006g142600和P002g2227003因表达、与细胞分裂素相关的P005g2489和P005g2376基因表达的影响。结果显示,Aroclor1254可促进毛白杨组培苗不定根分化,缩短不定根初根时间与分化率达100%的时间,提高不定根数目:在不定根诱导期,用Aroclor1254单独诱导,IAA/(ZR+dhZR)比值与阳性对照无显著差异,P006g142600、P002g222700、P009g125900、P005g2489和P005g2376基因表达变化趋势与IBA单独诱导下各基因表达变化趋势一致。为验证Aroclor1254是否具有生长素效应,以玉米(Zea mays)和转生长素报告基因DR5::GUS的拟南芥(Arabidopsis thaliana)为材料,观察Aroclor1254对胚芽鞘生长及DR5::GUS基因表达的影响。结果显示,一定浓度的Aroclor1254对胚芽鞘的生长无显著影响,但可诱导生长素报告基因表达。以上结果表明,多氯联苯类化合物Aroclor1254虽不属于植物生长调节剂,但具有毒物兴奋效应,在一定浓度下具有类似生长素的生物学活性。

分层教学对职业学校学生学业成绩的影响——基于国内42项实验研究的元分析

分层教学广泛应用于职业教育中,但其实践效果一直存在争议。本研究采用元分析方法,梳理并分析国内职业学校分层教学实践的26篇学位论文所提取出的42项实验研究的数据,揭示了在职业教育中实施分层教学的有效性。研究发现:分层教学对学生成绩的整体平均效应值为0.64,在职业学校实施分层教学能够显著提升学生的学业成绩;分层教学对学生成绩的影响受学科和教学周期的调节作用,分层教学在语言类学科、理科类学科和技术类学科中效果依次减弱,而教学的积极效果随着教学周期的增加而增强;在中等、高等职业学校实施分层教学均能显著提高学生成绩,但学段对教学效果的调节作用不显著。总之,在职业学校实施分层教学能够显著提升学生的学业成绩,并且具有长期效应。职业学校实施分层教学有助于扭转职业教育当前的发展局面,有助于满足社会对多样化人才培养的需要,也有助于推动职业教育的高质量发展。因此,建议从教学标准、教学方案、实践探索和学业成果评定出发,形成职业学校分层教学的实践方案。在未来研究中,我们将进行多个维度的效果分析,并进行学科分层教学设计的实证研究。

Neutrophil-derived heparin binding protein triggers vascular leakage and synergizes with myeloperoxidase at the early stage of severe burns(With video)

Background:Burn shock caused by vascular leakage is one of the main causes of high mortality in severe burn injury.However,the pathophysiological mechanism of vascular leakage is still unclear.The purpose of this study was to explore the molecular mechanism of vascular leakage in the early stage of severe burn and provide a new target for the treatment of severe burns.Methods:Neutrophils were isolated from human peripheral blood by magnetic beads sorting.ELISA was used to detect neutrophil-derived granule proteins and glycocalyx injury products in plasma.The vascular leakage and neutrophil movement were assessed by in vivo laser confocal imaging in mice,and high-quality video were provided.Adhesion-related molecules were investigated by qRT-PCR.The damage to glycocalyx of mice vascular endothelial cellswas observed by transmission electron microscope and scanning electron microscope.Proteomic analysis,flow cytometry and immunofluorescence were used to further study the relationship between human peripheral blood neutrophil-derived hypochlorite(HOCl)and CD44 of human vascular endothelial cells.Results:In this study,we found that rapidly increasing activated neutrophils secrete heparin binding protein(HBP)andmyeloperoxidase(MPO)after severe burn injury.Increased HBP triggers vascular leakage with synergy of MPO,results in systemic edema and burn shock.Furthermore,we found that the MPO catalytic product HOCl but not MPO triggers CD44 extracellular domain shedding from vascular endothelial cells to damage the glycocalyx.Damage to the glycocalyx results in firm adhesion of neutrophils and increases vascular leakage.However,MPO inhibitors partially protect the glycocalyx of vascular endothelial cells.The combination of HBP and MPO inhibitors markedly reduces vascular leakage and systemic edema in the early stage of severe burns.Conclusions:Taken together,these data reveal that neutrophil-derived HBP and MPO play an important synergies role in triggering vascular leakage at the early stage of severe burns.Targeted intervention in these two biomolecules may introduce new strategies for helping to reduce large amount of fluid loss and subsequent burn shock.

Effects of cowpea(Vigna unguiculata) root mucilage on microbial community response and capacity for phenanthrene remediation

Biodegradation of polycyclic aromatic hydrocarbons（PAHs） is normally limited by their low solubility and poor bioavailability. Prior research suggests that biosurfactants are synthesized as intermediates during the production of mucilage at the root tip. To date the effects of mucilage on PAH degradation and microbial community response have not been directly examined. To address this question, our research compared 3 cowpea breeding lines（Vigna unguiculata） that differed in mucilage production for their effects on phenanthrene（PHE） degradation in soil. The High Performance Liquid Chromatography results indicated that the highest PHE degradation rate was achieved in soils planted with mucilage producing cowpea line C1, inoculated with Bradyrhizobium, leading to 91.6% PHE disappearance in 5 weeks. In root printing tests, strings treated with mucilage and bacteria produced larger clearing zones than those produced on mucilage treated strings with no bacteria or bacteria inoculated strings. Experiments with14C-PHE and purified mucilage in soil slurry confirmed that the root mucilage significantly enhanced PHE mineralization（82.7%）, which is 12% more than the control treatment without mucilage. The profiles of the PHE degraders generated by Denaturing gradient gel electrophoresis suggested that cowpea C1, producing a high amount of root mucilage, selectively enriched the PHE degrading bacteria population in rhizosphere. These findings indicate that root mucilage may play a significant role in enhancing PHE degradation and suggests that differences in mucilage production may be an important criterion for selection of the best plant species for use in phytoremediation of PAH contaminated soils.

Visible-Light-Promoted[3+2]Cycloaddition of 2H-Azirines with Quinones:Access to Substituted Benzo[f]isoindole-4,9-diones

A visible-light-promoteded[3+2]cycloaddition reaction of 2H-azirines with quinones has been developed under mild reaction con-ditions.The reaction provides a general and efficient strategy for the synthesis of the benzo[f]isoindole-4,9-diones scaffold via a tandem[3+2]cyclization/oxidative aromatization with molecular oxygen.Furthermore,preliminary studies for photocatalytic prop-erties show that the benzo[f]isoindole-4,9-diones 3 can be used as photocatalysts in several organic transformations.