Numerical study of submerged bending vegetation under unidirectional flow

Submerged vegetation commonly grows and plays a vital role in aquatic ecosystems,but it is also regarded as a barrier to the passing flow.Numerical simulations of flow through and over submerged vegetation were carried out to investigate the effect of vegetation density on flow field.Numerical simulations were computationally set up to replicate flume experiments,in which vegetation was mimicked with flexible plastic strips.The fluid-structure interaction between flow and flexible vegetation was solved by coupling the two modules of the COMSOL packages.Two cases with different vegetation densities were simulated,and the results were successfully validated against the experimental data.The contours of the simulated time-averaged streamwise velocity and Reynolds stress were extracted to highlight the differences in mean and turbulent flow statistics.The turbulence intensity was found to be more sensitive to vegetation density than the time-averaged velocity.The developing length increased with the spacing between plants.The snapshots of the bending vegetation under instantaneous velocity and vorticity revealed that flexible vegetation responded to the effects of eddies in the shear layer by swaying periodically.The first two rows of vegetation suffered stronger approaching flow and were prone to more streamlined postures.In addition,the origin of tip vortices was investigated via the distribution of vorticity.The results reveal the variation of flow properties with bending submerged vegetation and provide useful reference for optimizationofrestorationprojects.

核磁共振技术测定联萘酚的对映体纯度

手性联萘酚((±)-BINOL)制备是国内高校常开设的一个实验,其产品的对映体纯度测试是实验的重要一环。以2-甲酰基苯硼酸和(S)-(−)-1-苯乙胺的混合物作为手性试剂与联萘酚发生Bull-James Assembly反应,以此设计了核磁共振氢谱(^(1)H NMR)测定联萘酚对映体纯度的实验。实验结果表明,通过反应生成的对映体混合物的核磁信号,能准确地计算出(±)-BINOL的对映体纯度。以选定的苯环氢核信号计算出的(R)-BINOL含量与理论ee值有着良好的线性关系(R^(2)=0.9999)。此实验方法能够快速完成大量学生样品的测量,同时大大减少实验废液的产生量。学生通过此实验可对核磁共振技术有更进一步的了解。

2019年度国家自然科学基金临床肿瘤研究方向分析及思考

随着细胞生物学等学科的不断发展和深入,肿瘤学基础研究取得了一定进展,肿瘤学科申请项目数量及质量也逐渐提高。本文总结2019年度国家自然科学基金临床肿瘤学科面上项目、青年科学基金项目以及地区科学基金项目的申请与资助情况,并从不同角度深入分析面上项目的研究方向,针对临床肿瘤中非编码RNA、肿瘤免疫治疗、肿瘤微环境、肿瘤代谢等代表性研究方向,以及淋巴管新生、细胞焦亡及铁死亡、溶酶体及线粒体等研究前沿进行综述。

简易多路气体分流装置在有机实验教学中的应用

介绍了一种简易多路气体分流装置,可以简单方便地将惰性气体分流供应多个学生同时使用,并确保每条支路气流量充足。该套装置可以提高操作的安全性同时减少资源的浪费,它拆装方便,可以在不使用时进行存放储藏,有效地减小占有空间。

Growth induction of hepatic stimulator substance in hepatocytes through its regulation on EGF receptors

The cytosolic liver-specific growth factor-hepatic stimulator substance (HSS) has been shown to be able to amplify the rat hepatocyte proliferation responded to EGF. In order to get more insight into the mechanism, the regulatory effect of HSS on EGF-receptor(EGF-R) and the receptor phosphorylation at molecular level was studied. HSS partially purified from weanling rat liver was given to cultured hepatocytes and its influence on EGF-R specific binding and internalization as well as mRNA expression were investigated. The results showed that preincubation of hepatocytes with HSS could lead to an increase in [125I]-EGF binding to its receptors and inhibit EGFinduced receptor down-regulation. Furthermore, the overexpression of EGF-R mRNA stimulated by HSS was seen during 2-12 h after the incubation. Additionally, it was demonstrated with human hepatoma sMMC-7721 cells in Western blot that the EGF-R expression and the receptor autophosphorylation were increased with dose/timedependency after HSS treatment. These results strongly suggest that the mechanism of HSS action on hepatocyte growth might be related to its modulation on EGF-R and receptor-mediated signaling transduction.

High-coverage proteome analysis reveals the first insight of protein modification systems in the pathogenic spirochete Leptospira interrogans

细螺旋体病是感染人和大量动物的类螺旋体的病原的螺旋菌引起的普遍 zoonotic 疾病。由联合计算预言和高精确性的双人脚踏车团系列，我们修订了螺旋体 interrogans serovar Lai，为细螺旋体病负责的免费生活的病原的螺旋菌，为新奇基因的提供的实质的肽证据和新基因边界的染色体注解。随后，我们介绍了蛋白质表示和多重 posttranslational 修正(PTM ) 的高范围的 proteome 分析。约 64.3% 预言的 L。interrogans 蛋白质被检测 2 编目 540 蛋白质。同时，多重 PTM 的侧面并发地被建立，在总数 32 phosphorylated， 46 acetylated 和 155 methylated 蛋白质包含。在 serovar Lai 的 PTM 系统显示出唯一的特征。L 的唯一的象真核细胞一样特征。interrogans 蛋白质修正在 phosphorylation 和精氨酸 methylation 被表明。这系统的分析在建议的初核质而且一个看法提供高范围的蛋白质表示和多重修正的全面信息不仅 evolutionarily 原始的 L。interrogans 与优核质在蛋白质修正系统分享重要类似。

从早期小细胞肺癌患者中选择以手术作为局部治疗的候选者:基于人群的分析

背景与目的手术和放疗被认为是治疗小细胞肺癌(small cell lung cancer,SCLC)的局部疗法。本研究旨在基于"第8版肺癌TNM分期指南",在I或II期SCLC患者中选择接受手术作为局部治疗的候选者。方法从监测、流行病学和最终结果(Surveillance, Epidemiology and End Results,SEER)数据库中选择在2004年至2013年间被诊断为SCLC的患者。根据"第8版肺癌TNM分期指南",对这些SCLC患者的TNM分期进行了重新分类。I或II期SCLC患者被纳入本研究。在不同TNM分期中分别比较接受手术和放疗作为局部治疗的患者间的总生存(overall survival,OS)和肺癌特异性生存(lung cancer-specific survival,LCSS)。多因素分析用于评价与生存相关的多种因素。结果在纳入本研究的2129例患者中,387例(18.2%)接受了手术治疗,1032例(48.5%)接受了放疗作为局部治疗,154例(7.2%)接受了手术和放疗,556例(26.1%)未接受任何手术或放疗。在T1–2N0期(肿瘤大小≤50 mm,无阳性淋巴结)患者中,接受手术的患者5年OS和LCSS率高于接受放疗的患者(T1N0:46.0?%vs. 23.8%,P <0.001,58.4%vs. 36.4%,P <0.001;T2N0:42.6%vs. 24.7%,P=0.004,48.8%vs. 31.3%,P=0.011)。多因素分析结果显示,手术与低死亡风险相关。然而,在T3N0或T1–2N1(IIB期)SCLC患者中,接受手术的患者5年OS和LCSS率并未高于接受放疗的患者(T3N0:16.2%vs. 26.5%,P=0.085,28.7%vs. 30.9%,P=0.372;T1–2N1:20.3%vs. 29.0%,P=0.146,25.6%vs. 35.5%,P=0.064)。结论基于绝大多数接受手术或放疗的I或II期SCLC患者也接受了特定类型的全身治疗的假设,只有T1–2N0期SCLC患者可以从作为局部治疗的手术中获益。T3N0或T1–2N1期SCLC患者可考虑将放疗作为局部治疗。

有机化学双语教学的课程思政探讨

课程思政在满足教育需求的同时,需要结合学科发展特点发掘思政新元素。本文介绍了南京大学有机化学双语教学团队在课程思政改革中取得的阶段性成绩,探讨在基础有机化学双语教学课堂中引入中国有机化学家贡献的必要性,对增强学生文化自信、提升课程学习兴趣、塑造科学精神与品质和培养爱国主义情怀等方面有积极作用。

Resazurin as an indicator of reducing capacity for analyzing the physiologic status of deep-sea bacterium Photobacterium phosphoreum ANT-2200

Resazurin(RZ)is a weakly fl uorescent blue dye and can be reduced irreversibly to highly fl uorescent pink resorufi n(RF)that is reduced reversibly to colorless dihydroresorufi n(hRF)by photodeoxygenation,chemical reaction and reductive organic compounds produced through cell metabolism.Because of the reliable and sensitive fl uorescence-color change and noninvasive features,RZ has been used widely as a redox indicator in cell viability/proliferation assays for bacteria,yeast,and mammalian cells.However,RZ is used rarely for physiological characterization of marine microorganisms.Here,we developed a custom-made irradiation and absorption-analysis device to assess the reducing capacity and physiologic status of marine bacterial cultures.We measured the absorption spectra of RZ,RF,and hRF in the presence of the reducing compound Na 2 S and under visible-light irradiation.After establishing appropriate parameters,we monitored the color changes of RZ and its reduced derivatives to evaluate the coherence between reducing capacity,bioluminescence and growth of the deep-sea bacterium Photobacterium phosphoreum strain ANT-2200 under various conditions.Emission of bioluminescence is an oxidation process dependent upon cellular reducing capacity.Growth and bioluminescence of ANT-2200 cell cultures were impeded progressively with increasing concentrations of RZ,which suggested competition for reducing molecules between RZ at high concentration with reductive metabolism.Therefore,caution should be applied upon direct addition of RZ to growth media to monitor redox reactions in cell cultures.Analyses of the instantaneous reduction velocity of RZ in ANT-2200 cell cultures showed a detrimental eff ect of high hydrostatic pressure and high coherence between the reducing capacity and bioluminescence of cultures.These data clearly demonstrate the potential of using RZ to characterize the microbial metabolism and physiology of marine bacteria.

A New Tetranuclear Copper(Ⅰ) Complex of Dithiolate Ligand Fused with TTF Moiety

A tetranuclear copper (I) complex of the ditholate ligand fused with a TTF moiety hasbeen synthesized and characterized crystallographically. This is the first example of a metaJ clustercoordinated with the new type ligand. The complex shows interesting redox and radical properties.

Characteristics of MBR Oily Sludge and Its Influence on Membrane Fouling under Two Aeration Modes

A membrane bioreactor(MBR)with ordinary aeration(reactor R1)and a MBR with microporous aeration(reactor R2)are conducted in parallel to investigate the characteristics of oily sludge and its effect on membrane fouling.The results indicate that the order of membrane fouling rate from high to low is:reactor R1 dissolved oxygen(DO)(1 mg/L)>reactor R2 DO(1 mg/L)>reactor R1 DO(4 mg/L)>reactor R2 DO(4 mg/L).Membrane fouling rate is not related to oily sludge concentration but to oily sludge sedimentation performance and the small particle oily sludge is the key factor to affect the membrane fouling.The soluble microbial products(SMP)are examined by three-dimensional excitation-emission matrix(3DEEM)fluorescence spectra.3DEEM spectra demonstrate that the main organic substances of the SMP in two reactors are tyrosine aromatic protein,fulvic acid-like substances and soluble microbial products under DO are1 mg/L and 4 mg/L,respectively.The proportion sum of fulvic acid-like substances and soluble microbial products is the key factor affecting membrane fouling,and membrane fouling accelerates as the ratio increases.

Cellular metabolism: A key player in cancer ferroptosis

Cellular metabolism is the fundamental process by which cells maintain growth and self-renewal.It produces energy,furnishes raw materials,and intermedi-ates for biomolecule synthesis,and modulates enzyme activity to sustain normal cellular functions.Cellular metabolism is the foundation of cellular life processes and plays a regulatory role in various biological functions,including pro-grammed cell death.Ferroptosis is a recently discovered form of iron-dependent programmed cell death.The inhibition of ferroptosis plays a crucial role in tumorigenesis and tumor progression.However,the role of cellular metabolism,particularly glucose and amino acid metabolism,in cancer ferroptosis is not well understood.Here,we reviewed glucose,lipid,amino acid,iron and sele-nium metabolism involvement in cancer cell ferroptosis to elucidate the impact of different metabolic pathways on this process.Additionally,we provided a detailed overview of agents used to induce cancer ferroptosis.We explained that the metabolism of tumor cells plays a crucial role in maintaining intracellu-lar redox homeostasis and that disrupting the normal metabolic processes in these cells renders them more susceptible to iron-induced cell death,resulting in enhanced tumor cell killing.The combination of ferroptosis inducers and cel-lular metabolism inhibitors may be a novel approach to future cancer therapy and an important strategy to advance the development of treatments.

Discovery of Alkaloid Quinazolone-Derived Imidazolenones with Novel Structural Scaffolds of Multitargeting Antibacterial Potential

Alkaloids are one of the prominent members in the development of new antimicrobial agents.This work discovered a class of alkaloid quinazolone-derived imidazolenones as novel structural type of antibacterial agents with large potential to treat severe bacterial infections in the agricultural and food field.Preliminary bioactive assay displayed that some of the prepared compounds exhibited good inhibition against the tested strains,and cyclohexylimidazole-derived 7-fluoroquinazolone 22a(MIC=0.002 mmol/L)exhibited a 12.5-fold stronger inhibition than norfloxacin against Escherichia coli ATCC 25922.Further studies revealed that compound 22a not only possessed the ability of rapid bactericidal property and low propensity to develop resistance but also showed low cytotoxic effects toward red blood cells.The preliminary mechanism exploration indicated that compound 22a could cause membrane damage by disrupting bacterial membrane as well as depolarizing the cell membrane.Moreover,compound 22a could insert into DNA,which might hinder the replication of DNA.Molecular docking suggested that compound 22a could bind to gyrase and topoisomerase,which might be due to the suppressed expression of related genes.Meanwhile,compound 22a could disorder the metabolism and stimulate the production of reactive oxygen species to affect bacterial growth.The series of investigations suggested the promise of alkaloid quinazolone-derived imidazolenones as novel multitargeting antibacterial candidates for treatment of bacterial infections.

Exosomes:key players in cancer and potential therapeutic strategy

Exosomes are extracellular vesicles secreted by most eukaryotic cells and participate in intercellular communication.The components of exosomes,including proteins,DNA,mRNA,microRNA,long noncoding RNA,circular RNA,etc.,which play a crucial role in regulating tumor growth,metastasis,and angiogenesis in the process of cancer development,and can be used as a prognostic marker and/or grading basis for tumor patients.Hereby,we mainly summarized as followed:the role of exosome contents in cancer,focusing on proteins and noncoding RNA;the interaction between exosomes and tumor microenvironment;the mechanisms that epithelial-mesenchymal transition,invasion and migration of tumor affected by exosomes;and tumor suppression strategies based on exosomes.Finally,the application potential of exosomes in clinical tumor diagnosis and therapy is prospected,which providing theoretical supports for using exosomes to serve precise tumor treatment in the clinic.

Selection of candidates for surgery as local therapy among early-stage small cell lung cancer patients: a population-based analysis

Background:Surgery and radiotherapy are considered local therapies for small cell lung cancer(SCLC).The present study aimed to select candidates for surgery as local therapy among patients with stage I or II SCLC,based on the eighth edition of the TNM classification for lung cancer.Methods:Patients diagnosed with SCLC between 2004 and 2013 were selected from the Surveillance,Epidemiology,And End Results database.The TNM stage of SCLC in these patients was re-classified according to the eighth edition of the TNM classification for lung cancer.Patients with stage I or II SCLC were included in the present study.Overall survival(OS)and lung cancer-specific survival(LCSS)were separately compared in the different TNM stages between patients who received surgery and radiotherapy as local therapy.Multivariate analysis was applied to evaluate multi-ple factors associated with survival.Results:Among the 2129 patients included in the present study,387(18.2%)received surgery,1032(48.5%)under-went radiotherapy as local therapy,154(7.2%)underwent surgery and radiotherapy,and 556(26.1%)did not undergo either surgery or radiotherapy.Among patients with T1-2N0(tumor size≤50 mm without positive lymph nodes)dis-ease,patients who underwent surgery had higher 5-year OS and LCSS rates than patients who received radiotherapy(T1N0:46.0%vs.23.8%,P<0.001,and 58.4%vs.36.4%,P<0.001,respectively;T2N0:42.6%vs.24.7%,P=0.004,and 48.8%vs.31.3%,P=0.011,respectively).Multivariate analysis results revealed that surgery was associated with low risk of death.However,among T3N0 or T1-2N1(stage IIB)SCLC patients,patients who underwent surgery did not have higher 5-year OS and LCSS rates than patients who received radiotherapy(T3N0:16.2%vs.26.5%,P=0.085,and 28.7%vs.30.9%,P=0.372,respectively;T1-2N1:20.3%vs.29.0%,P=0.146,and 25.6%vs.35.5%,P=0.064,respectively).Conclusions:Based on the assumption that the overwhelming majority of stage I or II SCLC patients who underwent surgery or radiotherapy also received certain types of systemic therapy,only patients with T1-2N0 SCLC may benefit from surgery as local therapy.Patients with T3N0 or T1-2N1 SCLC may consider radiotherapy as local therapy.

Scrolling bilayer WS2/MoS2 heterostructures for high-performance photo-detection

Recently,transition metal dichalcogenides(TMDCs)nanoscrolls have exhibited unique electronic and optical properties due to their spiral tubular structures,which are formed by rolling up monolayer TMDCs nanosheets.Inspired by the excellent physical and chemical properties of TMDCs van der Waals heterostructures(vdWHs),it is highly desirable to scroll TMDCs vdWHs for potential optoelectronic applications.In this work,WS2/MoS2 vdWHs nanoscrolls were massively prepared by dropping aqueous alkaline droplet on chemical vapor deposition(CVD)-grown bilayer WS2/MoS2 vdWHs,which were formed by growing monolayer WS2 islands on top of monolayer MoS2 nanosheets simultaneously.The optical microscopy(OM),atomic force microscopy(AFM),ultralow frequency(ULF)Raman spectroscopy and transmission electron microscopy(TEM)were utilized to characterize the WS2/MoS2 vdWHs nanoscrolls.As-obtained WS2/MoS2 vdWHs nanoscrolls exhibited new ULF breathing mode as well as shear mode peaks due to the strong interlayer interaction.Notably,the photosensitivities of WS2/MoS2 vdWHs nanoscrolls-based devices were about ten times higher than those of WS2/MoS2 vdWHs-based devices under blue,green and red lasers,respectively,which could be attributed to the ultrafast charge transfer at alternative WS2/MoS2 and MoS2/WS2 multi-interfaces in scrolled structure.Our work suggested that TMDCs vdWHs scrolls could be promising candidates for optoelectronic applications.

Effects of trace calcium and strontium on microstructure and properties of Cu-Cr alloys

Cu-0.57Cr-0.01Ca and Cu-0.58Cr-0.01Sr(wt.%)alloys were fabricated and processed by thermo-mechanical treatment.Their mechanical and electrical properties and microstructure were investigated in detail and compared with those of a Cu-0.57Cr(wt.%)alloy.The results showed that the softening resistance of the Cu-Cr alloy was significantly improved by the additions of Ca and Sr elements.Compared with the Cu-Cr alloy,the deformation microstructure of the Cu-Cr-Ca and Cu-Cr-Sr alloys was more difficult to recrystallize at elevated temperatures,and the Cr precipitates in the Cu-Cr-Ca and Cu-Cr-Sr alloys were smaller in size and had an FCC structure at any given aging state.The high strengths of the Cu-Cr-Ca and Cu-Cr-Sr alloys were mainly attributed to the dislocation strengthening provided by high-density dislocations and the precipitate strengthening provided by fine Cr precipitates.First-principles calculation showed that the segregations of Ca and Sr atoms at interface between Cr precipitates and copper matrix were favorable in energetics.This segregation effectively hindered the growth of Cr precipitates and significantly enhanced the pinning effect on the motion of dislocations and subgrain boundaries,eventually leading to the improvement in the softening resistance of the Cu-Cr alloy.

Integrated metabolism and epigenetic modifications in the macrophages of mice in responses to cold stress

The negative effects of low temperature can readily induce a variety of diseases.We sought to understand the reasons why cold stress induces disease by studying the mechanisms of fine-tuning in macrophages following cold exposure.We found that cold stress triggers increased macrophage activation accompanied by metabolic reprogramming of aerobic glycolysis.The discovery,by genome-wide RNA sequencing,of defective mitochondria in mice macrophages following cold exposure indicated that mitochondrial defects may contribute to this process.In addition,changes in metabolism drive the differentiation of macrophages by affecting histone modifications.Finally,we showed that histone acetylation and lactylation are modulators of macrophage differentiation following cold exposure.Collectively,metabolism-related epigenetic modifications are essential for the differentiation of macrophages in cold-stressed mice,and the regulation of metabolism may be crucial for alleviating the harm induced by cold stress.

Study of Relationship Between the Blood Supply of the Extrahepatic Bile Duct and Duct Supply Branches from Gastroduodenal Artery on Imaging and Anatomy

Background： Liver transplantation has become the treatment of choice for patients with end-stage acute or chronic hepatic disease. Bile duct complications are common events after liver transplantation. The aim of this study was to evaluate the blood supply of the human bile duct and identify the underlying mechanisms of bile duct complications after liver transplantation. Methods： The duct supply branches from gastroduodenal artery and blood supply of extrahepatic bile duct system were re-evaluated through selective hepatic angiography from 600 patients. In addition, 33 cadavers were injected with latex casting material into the common hepatic artery, then the extrahepatic bile duct and the branches from the common hepatic artery were carefully dissected to visualize the gastroduodenal artery and its branching to the extrahepatic bile duct. Results： The bile duct artery arose from the branch of the gastroduodenal artery in 8.1% （49/600）. Of these 49 individuals, the bile duct artery was supplied by the gastroduodenal artery （61.22%, 30/49）, the proper hepatic artery （14.29%, 7/49）, or both the gastroduodenal artery and the proper hepatic artery （24.49%, 12/49）. In our study of 33 cadavers, the percentage that the bile duct artery arose from the gastroduodenal artery was 27.27%. The blood supply to the bile extrahepatic bile ducts was divided into different segments and formed longitudinal and arterial network anastomosed on the walls of the duct. Conclusions： There is a close relationship between the duct supply branches from gastroduodenal artery and the blood supplying patterns of the extrahepatic bile duct system. In liver transplant surgery, the initial part of the gastroduodenal artery is preferred to be preserved in the donor liver. It is of great significance to improve the success rate of operation and reduce complications.

Single-and few-layer 2H-SnS_(2)and 4H-SnS_(2) nanosheets for high-performance photodetection

The properties of two-dimensional(2D)materials are highly dependent on their phase and thickness.Various phases exist in tin disulfide(SnS_(2)),resulting in promising electronic and optical properties.Hence,accurately identifying the phase and thickness of SnS_(2)nanosheets is prior to their optoelectronic applications.Herein,layered 2H-SnS_(2)and 4H-SnS_(2)crystals were grown by chemical vapor transportation and the crystalline phase of SnS_(2)was characterized by X-ray diffraction,ultralow frequency(ULF)Raman spectroscopy and high-resolution transmission electron microscope.As-grown crystals were mechanically exfoliated to single-and few-layer nanosheets,which were investigated by optical microscopy,atomic force microscopy and ULF Raman spectroscopy.Although the 2H-SnS_(2)and 4H-SnS_(2)nanosheets have similar optical contrast on SiO_(2)/Si substrates,their ULF Raman spectra obviously show different shear and breathing modes,which are highly dependent on their phases and thicknesses.Interestingly,the SnS_(2)nanosheets have shown phase-dependent electrical properties.The 4H-SnS_(2)nanosheet shows a current on/off ratio of 2.58×10^(5) and excellent photosensitivity,which are much higher than those of the 2H-SnS_(2)nanosheet.Our work not only offers an accurate method for identifying single-and few-layer SnS_(2)nanosheets with different phases,but also paves the way for the application of SnS_(2)nanosheets in highperformance optoelectronic devices.