含噻二唑季铵盐表面活性剂对Q235钢的缓蚀性能

通过表面张力法研究一种含噻二唑季铵盐表面活性剂(MTOTB)在1 mol/L HCl溶液中的表面活性;通过电化学测试、静态失重和表面形貌分析研究MTOTB及相应的2-巯基-5-甲基-1,3,4-噻二唑(MMTD)在1 mol/L HCl溶液中对Q235碳钢的缓蚀性能。结果表明,MTOTB在1 mol/L HCl溶液中的临界胶束浓度为0.36 mmol/L;当添加浓度为0.5 mmol/L时,MTOTB对在1 mol/L HCl溶液中浸泡48 h碳钢片的缓蚀率可达95.34%,同样条件下,MMTD对碳钢的缓蚀率为78.34%,说明MTOTB对碳钢的腐蚀抑制效率显著优于MMTD。SEM-EDS表明,MTOTB可以吸附在碳钢表面,有效抑制碳钢片的腐蚀。

Gt/Gt/1队列模型稳态性能指标的研究

针对到达率随时间变化的单服务台Gt/Gt/1队列模型,假定等待空间无限,在给定到达率函数的基础上,应用随机过程极限和概率测度收敛的相关知识,得到该队列模型各稳态性能指标的收敛极限。

NO_x Release from Snow and Ice Covered Surface in Polar Regions and the Tibetan Plateau

在雪和空气之间的 NOx 的交换在大气的部件上有重要影响，在 overlying 边界 layer.Such 交换的光化学的进程增加空气的氧化能力并且可以在从冰 cores.In 被检索的空气信号上有关键影响最近的年，被日光照射了的雪和冰被表明了是在纸从雪和冰在 NOx 的版本上使彻底的评论成为的极的大气的边界 layer.This 的重要 NOx 来源。

Preparation and Characterization of TiO₂Photocatalytic Thin Film and Its Compounds by Micro-Arc Oxidation Technique

Mesoporous TiO2 ceramic films have been prepared upon the Ti alloy substrate by the micro-arc oxidation (MAO) technology. To enhance the photo-catalytic property of the films, Eu2O3 particles were added into the electrolyte solution of Na2CO3/Na2SiO3. Scanning electron microscope (SEM), energy dispersive (EDS), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) are employed to characterize the modified films. Diffuse reflectance spectra (DRS) test, photo-generated current test and photo decomposition test are applied to evaluate the photo-catalytic property of the modified films. The results show that Eu2O3 transformed into one-dimensional (1-D) nano-wires embedded within the composite film, and the film has high photo-catalytic property.

Protein post-translational modifications in auxin signaling

Protein post-translational modifications(PTMs),such as ubiquitination,phosphorylation,and small ubiquitin-like modifier(SUMO)ylation,are crucial for regulating protein stability,activity,subcellular localization,and binding with cofactors.Such modifications remarkably increase the variety and complexity of proteomes,which are essential for regulating numerous cellular and physiological processes.The regulation of auxin signaling is finely tuned in time and space to guide various plant growth and development.Accumulating evidence indicates that PTMs play critical roles in auxin signaling regulations.Thus,a thorough and systematic review of the functions of PTMs in auxin signal transduction will improve our profound comprehension of the regulation mechanism of auxin signaling and auxin-mediated various processes.This review discusses the progress of protein ubiquitination,phosphorylation,histone acetylation and methylation,SUMOylation,and S-nitrosylation in the regulation of auxin signaling.

管状g-C_(3)N_(4)/ZnIn_(2)S_(4)纳米片异质结通过促进电荷分离实现高效光催化合成H_(2)O_(2)

过氧化氢(H_(2)O_(2))是一种环保的活性氧和重要的绿色氧化剂.然而,到目前为止,实现高效和绿色可持续H_(2)O_(2)生产仍然面临挑战.本文中,我们展示了管状氮化碳(TCN)和ZnIn_(2)S_(4)(ZIS)纳米片(TCN/ZIS)异质结的光催化产H_(2)O_(2)性能:3小时内H_(2)O_(2)的生产速率为2.77 mmol g-1h-1,分别为单独的TCN和ZIS的3.4倍和23.1倍.实验结果表明,TCN/ZIS异质结优异的光催化活性主要源于ZIS促进了电荷分离从而通过将O_(2)还原为·O_(2)-,然后生成H_(2)O_(2)来实现质子耦合电子转移过程.该工作提出了一种高效、绿色的H_(2)O_(2)生产策略,对环境修复具有重要科学意义和实用价值.

NAC1 regulates root ground tissue maturation by coordinating with the SCR/SHR-CYCD6;1 module in Arabidopsis

Precise spatiotemporal control of the timing and extent of asymmetric cell divisions(AcDs)is essential for plant development.In the Arabidopsis root,ground tissue maturation involves an additional AcD of the endo-dermis that maintains the inner cell layer as the endodermis and generates the middle cortex to the outside.Through regulation of the cell cycle regulator CYCLIND6;1(CYCD6;1),the transcription factors SCARECROW(SCR)and SHORT-ROOT(SHR)play critical roles in this process.In the present study,we found that loss of function of NAC1,a NAC transcription factor family gene,causes markedly increased periclinal cell divisions in the root endodermis.Importantly,NAC1 directly represses the transcription of CYCD6;1 by recruiting the co-repressor TOPLESS(TPL),creating a fine-tuned mechanism to maintain proper root ground tissue patterning by limiting production of middle cortex cells.Biochemical and genetic analyses further showed that NAC1 physically interacts with SCR and SHR to restrict excessive periclinal cell divisions in the endo-dermis during root middle cortex formation.Although NAC1-TPL is recruited to the CYCD6;1 promoter and represses its transcription in an SCR-dependent manner,NAC1 and SHR antagonize each other to regu-late the expression of CYCD6;1.Collectively,our study provides mechanistic insights into how the NAC1-TPL module integrates with the master transcriptional regulators SCR and SHR to control root ground tissue patterning by fine-tuning spatiotemporal expression of CYCD6;1 in Arabidopsis.

1个DYNC2H1基因变异导致的短肋多指综合征Ⅲ型家系的遗传学分析

本文报道1个连续3次妊娠早孕期超声均提示胎儿四肢短小家系的遗传学分析。取第2次妊娠引产胎儿组织行染色体核型分析及全外显子组测序,结果提示DYNC2H1基因存在EX64-EX83 Del及c.8190G>T杂合变异。实时荧光定量聚合酶链反应及Sanger测序验证2个变异分别遗传自表型正常的父亲和母亲,前者为疑似致病性变异,后者为临床意义未明变异。综合病史及变异基因特点,高度怀疑胎儿为常染色体隐性遗传的复合杂合变异导致的短肋多指综合征Ⅲ型。第3次妊娠胎儿引产后采用实时荧光定量聚合酶链反应和Sanger测序进行验证,结果与第2次妊娠胎儿一致。由于第2、3次妊娠胎儿表型相似,提示DYNC2H1基因EX64-EX83 Del及c.8190G>T杂合变异可能是该家系短肋多指综合征Ⅲ型的致病变异。

SIZ1 negatively regulates aluminum resistance by mediating the STOP1–ALMT1 pathway in Arabidopsis

Sensitive to proton rhizotoxicity 1(STOP1) functions as a crucial regulator of root growth during aluminum(Al) stress. However, how this transcription factor is regulated by Al stress to affect downstream genes expression is not well understood. To explore the underlying mechanisms of the function and regulation of STOP1, we employed a yeast two hybrid screen to identify STOP1-interacting proteins. The SUMO E3 ligase SIZ1, was found to interact with STOP1 and mainly facilitate its SUMO modification at K40 and K212 residues. Simultaneous introduction of K40 R and K212 R substitutions in STOP1 enhances its transactivation activity to upregulate the expression of aluminum-activated malate transporter 1(ALMT1)via increasing the association with mediator 16(MED16) transcriptional co-activator. Loss of function of SIZ1 causes highly increased expression of ALMT1, thus enhancing Al-induced malate exudation and Al tolerance. Also, we found that the protein level of SIZ1 is reduced in response to Al stress. Genetic evidence demonstrates that STOP1/ALMT1 is epistatic to SIZ1 in regulating root growth response to Al stress. This study suggests a mechanism about how the SIZ1–STOP1–ALMT1 signaling module is involved in root growth response to Al stress.

The novel ER stress inducer Sec C triggers apoptosis by sulfating ER cysteine residues and degrading YAP via ER stress in pancreatic cancer cells

Pancreatic adenocarcinoma(PAAD) is one of the most lethal malignancies. Although gemcitabine(GEM) is a standard treatment for PAAD, resistance limits its application and therapy. Secoemestrin C(Sec C) is a natural compound from the endophytic fungus Emericella, and its anticancer activity has not been investigated since it was isolated. Our research is the first to indicate that Sec C is a broad-spectrum anticancer agent and could exhibit potently similar anticancer activity both in GEM-resistant and GEM-sensitive PAAD cells. Interestingly, Sec C exerted a rapid growth-inhibiting effect(80% death at 6 h), which might be beneficial for patients who need rapid tumor shrinkage before surgery. Liquid chromatography/mass spectrometry and N-acetyl-L-cysteine(NAC) reverse assays show that Sec C sulfates cysteines to disrupt disulfide-bonds formation in endoplasmic reticulum(ER) proteins to cause protein misfolding, leading to ER stress and disorder of lipid biosynthesis. Microarray data and subsequent assays show that ER stress-mediated ER-associated degradation(ERAD) ubiquitinates anddownregulates YAP to enhance ER stress via destruction complex(YAP-Axin-GSK-βTr CP), which also elucidates a unique degrading style for YAP. Potent anticancer activity in GEM-resistant cells and low toxicity make Sec C a promising anti-PAAD candidate.

Susceptibility of patients with chronic obstructive pulmonary disease to heart rate difference associated with the short-term exposure to metals in ambient fine particles:A panel study in Beijing,China

Susceptibility of patients with chronic obstructive pulmonary disease(COPD)to cardiovascular autonomic dysfunction asso-ciated with exposure to metals in ambient fine particles(PM2.5,particulate matter with aerodynamic diameter≤2.5µm)remains poorly evidenced.Based on the COPDB(COPD in Beijing)panel study,we aimed to compare the associations of heart rate(HR,an indicator of cardiovascular autonomic function)and exposure to metals in PM2.5 between 53 patients with COPD and 82 healthy controls by using linear mixed-effects models.In all participants,the HR levels were significantly associated with interquartile range increases in the average concentrations of Cr,Zn,and Pb,but the strength of the associations differed by exposure time(from 1.4%for an average 9 days(d)Cr exposure to 3.5%for an average 9 d Zn exposure).HR was positively associated with the average concentrations of PM2.5 and certain metals only in patients with COPD.Associations between HR and exposure to PM2.5,K,Cr,Mn,Ni,Cu,Zn,As,and Se in patients with COPD significantly differed from those in health controls.Furthermore,association between HR and Cr exposure was robust in COPD patients.In conclusion,our findings indicate that COPD could exacerbate difference in HR following exposure to metals in PM2.5.

Erratum on “Engineering of a universal polymeric nanoparticle platform to optimize the PEG density for photodynamic therapy” [Sci. China. Chem., 2019, 62: 1379–1386]

In a recent publication [1], these images in Figures 6(b, c)(^NPEG-NPCe6 group), S7, S9 and S10 were inadvertently taken the incorrect images in the production. The corrected versions are shown below. And, the quantification of Ce6 fluorescence(as performed in Figure 6(c)) was also corrected(Figure S12).

Engineering of a universal polymeric nanoparticle platform to optimize the PEG density for photodynamic therapy

Nanocarrier-mediated photodynamic therapy(PDT)has attracted extensive attention due to its locoregional therapeutic effect,minimal toxicity to normal tissues,and activation of immune system capability.However,it is still unclear how the physicochemical properties of nanocarriers affect their PDT therapeutic efficacies,which could be very different from those for chemotherapy.Herein,to demonstrate the effect of PEG density on PDT efficacy,we synthesized a series of random polyphosphoesters(PPEs)with different PEG contents by regulating the molar ratios of these monomers,and then these PPEs were used to prepare chlorin e6(Ce6)-loaded polymeric nanoparticles with tunable PEG density.Thereafter,the PDT efficacies of these nanoparticles were carefully and comprehensively evaluated.We demonstrate that the moderate PEG density(3.01 PEG/nm^2)of nanocarrier exhibited the best PDT therapeutic efficacy in a mouse model of pancreatic cancer due to its efficient balance of prolonged circulation and tumor cellular uptake.

Long-term declining in carbon monoxide(CO)at a rural site of Beijing during 2006-2018 implies the improved combustion efficiency and effective emission control

Carbon monoxide(CO)is primarily the result of incomplete combustion,which has impor-tant impacts on the atmospheric chemical cycle and climate.Improved quantitative char-acterization of long-term CO trends is important for both atmospheric modeling and the design and implementation of policies to efficiently control multiple pollutants.Due to the limitations of high time-resolution and high-quality long-term observational data,studies on long-term trends in the CO concentration in China are quite limited.In this study,the observational data of the concentration of CO in a rural site of Beijing during 2006-2018 was used to analyze the long-term trend in CO concentration in Beijing.The Theil-Sen method and the generalized additive model(GAM)-based method,were used to conduct the trend estimation analysis.We found that the concentration of CO at the Shangdianzi site showed a significant downward trend during 2006-2018,with a decline rate of 22.8±5.1 ppbV per year.The declining trend in CO also showed phasic characteristics,with a fast decreasing rate during the period of 2006-2008,stable variations during the period of 2009-2013 and a continuous downward trend after 2013.The declining trend in the CO concentration in the south to west(S-W)sectors where the polluted air masses come from is more rapid than that in the sectors where the clean air masses come from.The declining trend in the CO concentration implies the improved combustion efficiency and the successful air pollution control policies in Beijing and the surrounding area.

Initiation and maintenance of plant stem cells in root and shoot apical meristems

Plant stem cells are a small group of cells with a self-renewal capacity and serve as a steady supply of precursor cells to form new differentiated tissues and organs in plants.Root stem cells and shoot stem cells,which are located in the root apical meristem and in the shoot apical meristem,respectively,play a critical role in plant longitudinal growth.These stem cells in shoot and root apical meristems remain as pluripotent state throughout the lifespan of the plant and control the growth and development of plants.The molecular mechanisms of initiation and maintenance of plant stem cells have been extensively investigated.In this review,we mainly discuss how the plant phytohormones,such as auxin and cytokinin,coordinate with the key transcription factors to regulate plant stem cell initiation and maintenance in root and shoot apical meristems.In addition,we highlight the common regulatory mechanisms of both root and shoot apical meristems.

A feedback regulation between ARF7-mediated auxin signaling and auxin homeostasis involving MES17 affects plant gravitropism

Gravitropism is an essential adaptive response of land plants.Asymmetric auxin gradients across plant organs,interpreted by multiple auxin signaling components including AUXIN RESPONSE FACTOR7(ARF7),trigger differential growth and bending response.However,how this fundamental process is strictly maintained in nature remains unclear.Here,we report that gravity stimulates the transcription of METHYL ESTERASE17(MES17)along the lower side of the hypocotyl via ARF7-dependent auxin signaling.The asymmetric distribution of MES17,a methyltransferase that converts auxin from its inactive form methyl indole-3-acetic acid ester(MeI AA)to its biologically active form free-IAA,enhanced the gradient of active auxin across the hypocotyl,which in turn reversely amplified the asymmetric auxin responses and differential growth that shape gravitropic bending.Taken together,our findings reveal the novel role of MES17-mediated auxin homeostasis in gravitropic responses and identify an ARF7-triggered feedback mechanism that reinforces the asymmetric distribution of active auxin and strictly controls gravitropism in plants.

Proteomics Study of COI1-regulated Proteins in Arabidopsis Flower

Jasmonates （JAs） are a new class of plant hormone that regulate expression of diverse genes to mediate various plant responses. The Arabidopsis F-box protein COI1 is required for plant defense and male fertility in JA signal pathway. To further investigate the regulatory role of COI1 in male fertility, we compared the proteomics profiles of Arabidopsis wild type （WT） flowers with coi1-1 mutant male-sterile flowers using two-dimensional difference gel electrophoresis coupled with matrix-assisted laser desoption/ionization-time-of-flight mass spectrometry. Sixteen proteins with potential function in specific biological processes such as metabolism processes and defense/stress responses were differentially expressed in WT and coi1-1 mutant flowers. Verification on a phi class glutathione transferase AtGSTF9, one out of these 16 identified proteins, revealed that the expression of AtGSTF9 was severely downregulated in flowers of coi1-1 mutant compared with that of WT. Further function analyses of these genes would provide new insights into the molecular basis of COil-regulated male fertility.

Determination of Triazine Herbicides in Environmental Water Samples by Acetonitrile Inorganic Salt Aqueous Two-Phase Microextraction System

Acetonitrile inorganic salt aqueous two-phase extraction method was established for the determination of triazine herbicides(simeton,cyanazine,desmetryn,terbumeton,terbuthylazine and dimethametryn)in environmental water samples by high-performance liquid chromatography(HPLC).The extraction solvents types and volume of acetonitrile,the inorganic salt types and amount of(NH_(4))_(2)SO_(4),extraction time and pH of sample solution were optimized by single-factor experiment and central composite design.Under the optimum extraction conditions,all linear ranges were obtained with coefficients of determination(r)≥0.9993.The limits of detection for this proposed method were in the range of 0.16-0.28μg/L for six triazine herbicides.The developed method has been successfully applied to the analysis of target triazine herbicides from lake,canal and moat in real-world water samples.The recoveries of target analytes were in the range from 87.0 to 110.9%and the relative standard deviation was lower than 7.3%.