Characteristics and Influencing Factors of Microplastics in Snow in the Inner Mongolia Plateau, China

Microplastics(MPs;<5 mm)have become one of the most prominent global environmental pollution problems.MPs can spread to high altitudes through atmospheric transport and can be deposited by rainfall or snowfall,potentially threatening the structure and function of natural ecosystems.MPs in terrestrial and aquatic ecosystems alter the growth and functional characteristics of organisms.However,little attention has been given to the possible harm associated with MPs deposited in snow,particularly in the context of global climate warming.MPs collected from surface snow in the Inner Mongolia Plateau,China,were used for quantitative analysis and identification.The results showed that MPs were easily detected,and the related concentration was approximately(68±10)–(199±22)MPsL1 in snow samples.Fibers were the most common morphology,the polymer composition was largely varied,and the abundance and composition of MPs were linked to human activity to a great extent.High-throughput sequencing results showed that the composition and abundance of microorganisms also differed in snow samples from areas with different MP pollution characteristics,indicating a considerable difference in microbial functional diversity.MPs may have an interference effect on the individual growth and functional expression of microorganisms in snow.In addition,the results showed that functional living areas(e.g.,landfills and suburban areas)in cities play an important role in the properties of MPs.For instance,the highest abundance of MPs was found in thermal power plants,whereas the abundance of polymers per sample was significantly lower in the suburban area.The MP contaminants hidden in snow can alter microbial structure and function and are therefore a potential threat to ecosystem health.

气驱油油气混相过程的界面传质特性及其分子机制

油气混相过程的界面传质特性对气驱提高原油采收率技术非常重要。本文针对吉林某油田的实际油组分,采用分子动力学模拟研究了气驱油过程,分析了不同气体和驱替压力下油气两相的状态变化以及界面特性,获得不同驱替气体的最小混相压力(MMP)。结果表明,随着驱替气体压力的升高,气相的密度逐渐增大,油相膨胀密度降低,气相与油相的混合程度增强,油气两相界面厚度增加,界面张力随之减小。同时发现,驱替相中二氧化碳浓度越高,在同等气体压力下,油气界面更厚,油气混合程度更高。纯CO_(2)驱油得到的MMP远远小于纯N;驱油,当这两种气体摩尔比为1:1混合时MMP介于两种纯气体之间,说明要达到同样的驱油效果二氧化碳需要的压力更小。最后,本文从分子微观作用力角度解释了驱替气体不同时影响油气混相程度的机制,通过分子平均作用势曲线发现油相分子对CO_(2)的吸引力要大于N;分子,因此CO_(2)分子更容易与油相混合,驱替效果更明显。

控制线结对降低切口缝线排异反应的初步观察

目的:探讨降低切口缝线排异反应的有效方法。方法:2012年6月至2013年12月间麦氏切口阑尾切除术140例,随机等分为新式缝合组和对照两组,新式缝合组采用控制线结措施,术后随访6个月,观察两组间线结排异反应发生情况。结果:两组在手术时间、住院时间等指标上无统计学差异,新式缝合组无残留线结,差异有统计学意义(P <0.05),未发生线结排异反应,对照组发生4例,差异有统计学意义(P <0.05)。结论:控制线结是降低切口线结排异反应发生简单、有效的方法。

聚乙二醇-氧化亚铜微胶囊防污涂料的制备及性能

采用葡萄糖还原-单凝聚法合成了聚乙二醇-氧化亚铜(PEG-Cu2O)微胶囊,并用透射电镜和红外光谱对微胶囊的结构组成和包覆效果进行了验证。以合成的微胶囊为防污剂,聚氨酯/环氧树脂(PU/EP)共混树脂为基体制备防污涂料试样,并对涂料试样的涂层硬度、抗冲击性、拉伸强度、剪切强度、吸水性能及释放性能等进行了测试。探究了防污剂的种类和用量对防污涂料性能的影响,结果发现与使用普通Cu2O作为防污剂的涂料试样相比,使用PEG-Cu2O微胶囊的涂料试样涂层硬度、抗冲击性、拉伸强度、剪切强度、吸水率和缓释效果等性能均有了较大幅度的提升和改善;但当PEG-Cu2O用量增加至40 phr时,微胶囊对防污涂料性能的改善效果有一定程度的减弱;综合考虑涂料试样的各种性能,确定PEG-Cu2O用量以20 phr为宜。对遴选的优异配方涂料进行浅海挂板防污试验,结果发现,用量为20 phr的微胶囊涂料达到了与商品防污涂料基本相当的防污效果。

防穴蚀微胶囊/环氧树脂涂料的制备及涂层结构

以甲基丙烯酸甲酯(BMA)、甲基丙烯酸丁酯(MMA)的共聚物为壁材、聚丙烯酰胺(PAM)水溶液为芯材,采用原位聚合法合成防穴蚀微胶囊,并将其加入环氧树脂中制成防穴蚀涂料。探究了硬度、附着力、抗冲击性、拉伸强度、最大吸水率等涂层力学性能的影响因素;采用磁致伸缩振动实验研究了涂料防穴蚀性能。结果表明,随着微胶囊用量及涂层厚度的增加,涂层防穴蚀性能提升但力学性能呈下降趋势。在此基础上,设计了一种新型结构涂层,即从涂层内部到表面,微胶囊含量由0%递增至5%,对比微胶囊均匀分布的涂层结构,新型涂层结构在力学性能和防穴蚀效果上均有显著提升。

伊贝沙坦治疗轻、中度原发性高血压临床观察

目的 观察伊贝沙坦治疗轻、中度原发性高血压病人的疗效及耐受性。方法 用伊贝沙坦治疗 186例轻、中度原发性高压病人 12周。结果 病人于服药第 2、4、6、8、12周时 ,显效率分别为 4 0 3%、4 7 3%、5 4 4 %、6 3 2 %、71 1% ;有效率分别为 12 3%、17 3%、2 0 9%、2 2 6 %、2 3 3%。总有效率分别为 5 2 6 % ,6 4 6 % ,75 3% ,85 8% ,94 4 %。单用伊贝沙坦治疗 ,收缩压、舒张压、平均血压于第2周便开始明显下降 ,此后 ,随治疗时间的延长 ,血压不断下降 ,降压治疗的最大效应发生在第 12周。整个治疗过程无严重副作用发生。结论 伊贝沙坦治疗轻、中度原发性高血压病人安全有效 ,其疗效在不同年龄及不同体重指数的病人之间无明显差别。

The optimal timing for delayed percutaneous coronary intervention in patients with ST-segment elevation myocardial infarction presenting beyond 12 hours after symptoms onset

Objective To evaluate the impact of the timing of delayed PCI on the outcomes of patients with STEMI missing out on early reperfusion therapy within 12 h after symptom onset and ascertain the eligible time window to perform delayed PCI.Methods Among 28,061 patients registered in China Acute Myocardial Infarction(CAMI)registry,a total of 3,048 stable patients with STEMI who did not underwent any early reperfusion therapy within 12 hours after symptom onset and received delayed PCI at recovery stage were finally enrolled.

Preliminary Study of Oxidative Stress in Human Hepatocellular Carcinoma and Adjacent Normal Liver Tissues

OBJECTIVE The antioxidative system in human hepatocellular carcinoma was investigated. METHODS The activities of cytosolic catalase (CAT), superoxide dismu-tase, glutathione peroxidase (GSH-Px), glutathione S-tranferase and levels of reduced glutathione, total protein thiols and malondialdehyde were assayed in 10 cases of hepatocellular carcinoma and adjacent normal liver. RESULTS Hepatoma tissues showed higher activities of CAT, GSH -Px and lower content of total antioxidative capacity compared to adjacent normal liver tissue (P<0.05). CONCLUSION These findings suggest that the antioxidative defense-related enzymes and antioxidants are largely regulated in hepatoma cells. However, the mechanism which is not clear requires further investigation.

Zr-MOFs loaded on polyurethane foam by polydopamine for enhanced dye adsorption

Zirconium-based metal-organic frameworks(Zr-MOFs)have attracted widespread attention due to their high specific surface area,high porosity,abundant metal active sites and excellent hydrothermal stability.However,Zr-MOFs materials are mostly powdery in nature and thus difficult to separate from aqueous media,which limits their application in wastewater treatment.In this study,PDA/Zr-MOFs/PU foam was constructed by growing Zr-MOFs nanoparticles on a dopamine-modified polyurethane foam substrate by in-situ hydrothermal synthesis as an adsorbent for removing dyes from wastewater.The results demonstrated that the polydopamine coating improves the dispersion of the Zr-MOFs nanoparticles on the substrate and enhances the interaction between the Zr-MOFs nanoparticles and the PU foam substrate.As a result,compared with Zr-MOFs/PU foam,the prepared PDA/ZrMOFs/PU foam exhibits higher adsorption capacity for crystal violet(CV)(63.38 mg/g)and rhodamine B(RB)(67.73 mg/g),with maximum adsorption efficiencies of CV and RB of 98.4%(pH=11)and 93.5%(pH=7),respectively,at a concentration of 10 mg/L.The PDA/Zr-MOFs/PU foam can simultaneously remove CV and RB from the mixed solution.Moreover,the PDA/ZrMOFs/PU foam still exhibits high stability and reusability after five cycles.

Combinatorial metabolic engineering of Saccharomyces cerevisiae for improved production of 7-dehydrocholesterol

7-Dehydrocholesterol(7-DHC),a key pharmaceutical intermediate in the production of vitamin D3,has a wide range of applications.To explore fermentative synthesis of 7-DHC,a 7-DHC-producing Saccharomyces cerevisiae strain was constructed by blocking the competitive pathway,eliminating rate-limiting steps,altering global reg-ulation,and pathway compartmentalization.After blocking the competitive pathway by disrupting ERG5 and ERG6 and introducing DHCR24 from Gallus gallus,S.cerevisiae produced 139.72 mg/L(17.04 mg/g dry cell weight,hereafter abbreviated as DCW)7-DHC.Subsequent alteration of global regulation by deleting ROX1 and overexpressing UPC2-1 increased 7-DHC production to 217.68 mg/L(37.56 mg/g DCW).To remove the accu-mulated squalene,the post-squalene pathway was strengthened by co-overexpression of PGAL1-driven ERG11 and PGAL10-driven ERG1,which improved 7-DHC titer and yield to 281.73 mg/L and 46.78 mg/g DCW,respectively,and reduced squalene content by 90.12%.We surmised that the sterol precursors in the plasma membrane and peroxisomes may not be accessible to the pathway enzymes,thus we re-localized DHCR24p and Erg2p-GGGGS-Erg3p to the plasma membrane and peroxisomes,boosting 7-DHC production to 357.53 mg/L(63.12 mg/g DCW).Iron supplementation further increased 7-DHC production to 370.68 mg/L in shake flasks and 1.56 g/L in fed-batch fermentation.This study demonstrates the power of global regulation and subcellular relocalization of key enzymes to improve 7-DHC synthesis in yeast.

Investigation on the radioactivity levels of seawater,sediments,and biota in Daya Bay,China

Objective:To investigate the radioactivity levels of seawater,sediments,and biota in the Daya Bay sea area,China,in order to establish the radioactivity baseline values,and provide basic data for the assessment of potential radiological risks that might result from the application of nuclear technology or human activities.Methods:Samples of seawater,sediments,and biota were collected from the Daya Bay sea area and analyzed.Their radioactivity baseline data were then compared with information from other regions in China and around the world reported in related literature.Results:For the seawater samples,the activity concentrations of natural radionuclide ^(40)K were 9.9-10.4 Bq/L,while ^(238)U,226Ra,^(210)Pb,^(137)Cs,and ^(110)Ag^(m) were below the minimum detectable activity(MDA).Regarding the sediment samples,the activity concentrations of ^(238)U,^(228)Ra,^(226)Ra,^(210)Pb,^(40)K,and ^(137)Cs were 38.1-40.4,49.1-53.7,32.6-38.6,59-95,590-650,and 0.48-0.88 Bq/(kg dry weight),respectively,while ^(110)Agm was below the MDA.For the marine shrimps in the biota samples,the activity concentrations of ^(228)Ra,^(226)Ra,^(40)K,and ^(137)Cs were 1.14-2.75,0.17-0.43,63-76,and 0.038-0.045 Bq/(kg wet weight),respectively,while ^(238)U,^(210)Pb,and ^(110)Agm were all below the MDA.Furthermore,for the marine fishes in the biota samples,the activity concentrations of ^(228)Ra,^(226)Ra,^(210)Pb,^(40)K,and ^(137)Cs were 2.1-19.7,0.32-3.78,<2.2-2.8,59-70,and<0.007-0.026 Bq/(kg wet weight),respectively,while ^(238)U and ^(110)Ag^(m) were all below the MDA.^(228)Ra was found to be concentrated in Osteomugil ophuyseni with 19.7 Bq/(kg wet weight).Conclusions:The radioactivity levels of seawater and marine sediments in the Daya Bay sea area are within the range of the normal background values.Osteomugil ophuyseni exhibited higher concentrations of ^(228)Ra than other species in this study,while the other species in the biota show no significant difference in the radioactivity levels from data in relevant literature.

Recent advances in F-containing iodate nonlinear optical materials

Metal iodates containing I(Ⅴ)with lone electron pairs in an asymmetric coordination geometry exhibit excellent second-harmonic generation(SHG)responses,wide transmission range and large band gaps.During the past ten years,metal iodates have been widely studied,and introducing large electronegative fluorine atoms into metal iodates has also attracted much attention.These F-containing iodates are different from pure iodates in terms of composition,symmetry and transmittance.Especially because oxide-fluoride heterolepic anion groups can exhibit interesting structure-directing properties,e.g.trans-and cis-directing properties,these F-containing iodates also have better structure designability.Therefore,in this review,we will review the research progress of F-containing iodates and address the effect of structure-directing properties of oxide-fluoride anions on the crystal structures of F-containing iodates.Since the valence of the central cations will greatly affect the distortions and configurations of the oxide-fluoride anion groups,these F-containing iodates will be classified and introduced according to the different valences of the central cations.

Preface to Nonlinear Optical Crystals

Nonlinear optical(NLO)crystals are core materials in laser frequency-conversion technique,and the requirement on the laser wavelength varies from one application to another.Now,the commercial NLO crystals,e.g.,KDP,LBO,BBO,KTP,AgGaS_(2),ZnGeP_(2),et al.,have prevailed in ultraviolet(UV)/visible and near-/mid-infrared region for decades.

Preface to Nonlinear Optical Crystals

Nonlinear optical(NLO)crystals can efficiently convert the frequency of common solid-state laser with fixed or limited wavelengths.Since the first observation of second-harmonic generation(SHG)phenomenon in the early 1960s,they have played an increasing role in the fields of laser spectra,precision measurements,and quantum information,as well as industrial laser processing,and so on.However,it is still challenging to rationally design and synthesize new NLO crystals.

Strategies of minimally invasive treatment for intrahepatic and extrahepatic bile duct stones

Cholellthiasis is a kind of common and multiple diseases. In recent years, traolttonal laparommy has been challenged by a minimally invasive surgery. Through literature review, the therapeutic method, effect, and complications of minimally invasive treatment of intrahepatic and extrahepatic bile duct stones by combining our practical experience were summarized as follows. （1） For intrahepatic bile duct stones, the operation may be selected by laparoscopie liver resection, laparoscopic common bile duct exploration （LCBDE）, or percutaneous transhepatic cholangioscopy. （2） For concomitant gallstones and common bile duct stones, the surgical approach can be selected as follows： laparoscopic cholecystectomy （LC） combined with endoscopic sphincterotomy （EST） or endoscopic papillary balloon dilatation, LC plus laparoscopic transcystic common bile duct exploration, LC plus LCBDE, and T-tube drainage or primary suture. （3） For concomitant intrahepatic and extrahepatic bile duct stones, laparoscopic liver resection, choledochoscopy through the hepatic duct orifice on the hepatectomy cross section, LCBDE, EST, and percutaneous transhepatic cholangioscopic lithotripsy could be used. According to the abovementioned principle, the minimally invasive treatment approach combined with the surgical technique and equipment condition will be significant in improving the therapeutic effect and avoiding the postoperative complications or hidden dangers of intrahepatic and extrahepatic bile duct stones.

生物入侵对黄河流域生态系统的影响及对策

黄河流域健康的生态系统是沿黄地区生态保护和高质量发展的核心。然而,随着经济高速发展和人类活动增加,大量的外来生物传入并占据黄河流域生态位。这些外来生物在黄河流域的大肆扩繁给黄河流域本土生物和生态系统带来了严重威胁,甚至严重影响人类健康。因此,研究黄河流域的外来生物入侵问题,并提出保护对策,对于黄河流域生态保护和高质量发展具有重大意义。本文主要从黄河流经九省区(包含黄河流域)外来入侵生物的传入特征、传播途径、种群动态、成灾机制以及入侵生物对黄河流域重要生物资源和生态系统的影响等方面进行综述,并提出了防控黄河流域生物入侵、保护黄河流域健康的生态系统的措施和对策。

Ba4M（CO3）2（BO3）2（M=Ba,Sr）:在开放体系下通过高温溶液法合成两种硼酸-碳酸盐（英文）

本文中,我们成功合成了两种复合的硼酸-碳酸盐Ba4M(CO3)2(BO3)2 (M=Ba,Sr).这是第一例在开放体系下合成的硼酸-碳酸盐.它们的结构由单晶X射线衍射确定,结晶在相同的Pnma空间群.它们的晶体结构是由BaO8多面体(SrO8多面体)、孤立的BO3和CO3三角形组成的三维网络结构.详细的结构分析表明,共生长的[Ba3(BO3)2]/[Ba2Sr(BO3)2]和[BaCO3]层是有利于这两种硼酸-碳酸盐的合成的.此外,还研究了它们的合成、光谱性质和热行为.

增温对莲子草属入侵植物与本地同属植物化学物质组成和天敌昆虫的影响

气候变暖影响植物生长和生理活动,然而气候变暖如何改变入侵植物化学物质组成并间接影响其与植食性昆虫互作还少有报道。本研究以入侵植物空心莲子草(Alternanthera philoxeroides)及其本地同属植物莲子草(A.sessilis)为对象,探究增温对其叶片化学物质组成的影响并进一步检验这些变化如何影响两种植食性昆虫虾钳菜披龟甲(Cassida piperata)和斜纹夜蛾(Spodoptera litura)的生长发育。通过模拟增温实验,探究增温对空心莲子草和莲子草13个叶片化学物质的影响,并用其饲养两种植食性昆虫,测量它们的生长和发育时间。研究结果显示,增温显著改变了空心莲子草和莲子草叶化学物质组成;增温降低了空心莲子草叶片氮浓度,增加了莲子草叶片总黄酮和总酚浓度;增温对其它营养物质(果糖、蔗糖、总可溶性糖和淀粉)随物种和具体物质发生改变;采用增温处理的莲子草饲养的虾钳菜披龟甲蛹重和斜纹夜蛾幼虫重量,以及增温处理的空心莲子草饲养的斜纹夜蛾幼虫重量,显著低于对照不增温处理;此外,采用增温处理的莲子草饲养的斜纹夜蛾幼虫发育时间显著延长。这些结果表明,增温对植物化学物质组成的影响随物种发生变化,增温对入侵植物和本地植物化学物质组成的影响间接改变了其与植食性昆虫的互作关系。

拥有深紫外截止边的Rb2Mg3（P2O7）2同质多晶的合成、表征和理论计算（英文）

本文结合孤立的P2O7二聚体和Mg O4四面体,采用高温熔液法合成了α和β-Rb2Mg3(P2O7)2同质多晶.α-Rb2Mg3(P2O7)2结晶于非中心对称P212121空间群,β-Rb2Mg3(P2O7)2结晶于中心对称P21/c空间群.两种结构均含有三维[Mg3P4O14]^2-阴离子骨架,而Rb+离子位于空间中.结构分析表明,孤立的P2O7通过调整其可变构型和取向以适合不同配位环境的阳离子,这有利于同质多晶Rb2Mg3(P2O7)2的形成.另外,从α-到β-Rb2Mg3(P2O7)2的相转变过程也可以通过粉末X射线衍射和热重-差热测试被进一步证明.紫外-可见-近红外漫反射光谱测试表明两种材料都有深紫外截止边(190 nm以下),并且α-Rb2Mg3(P2O7)2具有倍频效应,我们通过倍频密度计算研究了其倍频效应的来源.为了更好地理解上述化合物的结构性能关系,我们还进行了第一性原理计算.

Assembly of biosynthetic pathways in Saccharomyces cerevisiae using a marker recyclable integrative plasmid toolbox

A robust and versatile tool for multigene pathway assembly is a key to the biosynthesis of high- value chemicals. Here we report the rapid construction of biosynthetic pathways in Saccharomyces cerevisiae using a marker recyclable integrative toolbox （pUMRI） devel- oped in our research group, which has features of ready-to- use, convenient marker recycling, arbitrary element replacement, shuttle plasmid, auxotrophic marker inde- pendence, GAL regulation, and decentralized assembly. Functional isoprenoid biosynthesis pathways containing 4-11 genes with lengths ranging from -10 to -22 kb were assembled using this toolbox within 1-5 rounds of reiterative recombination. In combination with GAL- regulated metabolic engineering, high production of isoprenoids （e.g., 16.3 mg.g-1 dcw carotenoids）was achieved. These results demonstrate the wide range of application and the efficiency of the pUMRI toolbox in multigene pathway construction of S. cerevisiae.