电感耦合等离子体质谱仪在线稀释进样系统设计及其便捷测定氢甲酰化反应液中钴和磷元素

为了快速测定氢甲酰化反应有机相中钴和磷元素的浓度,对电感耦合等离子体质谱仪(ICP-MS)进样系统进行改造,实现直接对有机相进行分析.使用反应溶剂对待测物料进行在线自动稀释,然后直接进样测试元素的含量.样品的稀释倍数由进样泵参数进行校准,测试结果与手动稀释的误差低于3%.改进后的ICP-MS可以及时监测氢甲酰化反应过程中钴和磷浓度,发现实际生产过程中产能不足的问题,进一步指导促进增产的具体应对方案.

野鸦椿果实总三萜提取工艺考察及抑制HepG2细胞增殖活性研究

目的:明确野鸦椿果实总三萜的最佳提取工艺,并探究野鸦椿果实总三萜对HepG2细胞增殖的抑制作用。方法:以超声提取的方式,总三萜得率为指标,采用单因素试验结合响应面优化法考察野鸦椿果实总三萜最佳提取工艺。采用CCK-8法检测野鸦椿果实总三萜对HepG2细胞增殖抑制作用。结果:影响野鸦椿果实总三萜超声提取的因素顺序为溶剂浓度>提取时间>液料比,最优提取工艺条件为液料比为51∶1(mL·g^(-1)),甲醇浓度69%,提取时间58 min,提取率为(8.49±0.15)%。通过乙酸乙酯萃取和MCI柱色谱纯化后,野鸦椿总三萜纯度可达66.4%。野鸦椿总三萜对HepG2细胞增殖的抑制较好,呈剂量依赖性;IC_(50)为20.302±1.65μg·mL^(-1)。结论:野鸦椿果实总三萜超声提取最优工艺为液料比51∶1(mL·g^(-1)),甲醇浓度69%,超声提取58 min,该方法较为稳定,操作方便快捷。总三萜体外抑制HepG2细胞增殖效果良好。

沙库巴曲缬沙坦治疗高血压有效性与安全性的Meta分析

目的探索沙库巴曲缬沙坦治疗高血压的有效性及安全性。方法计算机检索中国知网、万方、中国生物医学文献数据库、PubMed、The Cochrane Library、Embase、Web of Science,搜集自建库至2023年8月1日沙库巴曲缬沙坦治疗高血压的随机对照试验。由两名研究者独立筛选文献、提取资料并评价纳入研究的偏倚风险。采用RevMan 5.3软件进行Meta分析。结果共纳入10项随机对照试验,包括4103例患者。Meta分析结果显示,相比对照组干预措施,沙库巴曲缬沙坦治疗前后的降压效应差异有统计学意义[SBP:MD=6.26,95%CI(4.10,8.42),P<0.001;DBP:MD=4.06,95%CI(1.78,6.34),P<0.001];血压达标率差异有统计学意义[RR=1.22,95%CI(1.08,1.38),P=0.002];沙库巴曲缬沙坦应用后不良反应发生率与对照组相比,差异无统计学意义[RR=1.04,95%CI(0.94,1.14),P>0.05]。结论沙库巴曲缬沙坦治疗高血压疗效显著,安全性较好。

镁基表面微弧氧化陶瓷膜的摩擦磨损特性

利用微弧氧化技术在AZ91D镁合金表层制备原位生长陶瓷膜,利用SEM、XRD等表征了镁基陶瓷膜,并研究了镁基陶瓷膜的摩擦磨损特性及磨损机理。结果表明,镁基陶瓷膜表面呈典型的微孔叠加多孔结构特征,其主要成分是Mg2SiO4、MgAl2O4、Mg3(PO4)2、MgO,膜层与基体结合紧密,结合力为14~15 N。不同载荷和不同摩擦速度等因素对镁基陶瓷膜的磨损都有很大的影响。随着载荷和滑动速度的增大,陶瓷膜的磨损失重也明显增大。油摩擦的磨耗较小,其磨损机理主要为疲劳磨损,同时也附带磨粒磨损。干摩擦的磨耗较大,其磨损是由磨粒和疲劳磨损共同造成的。

离子液体功能化金属/共价-有机框架材料在催化反应中应用

离子液体(ILs)功能化的金属有机框架(MOFs)和共价有机框架(COFs)材料兼具离子液体和MOFs/COFs的优点,是一种极具潜力的复合催化材料.MOFs和COFs材料固定的孔结构及较大的比表面积为负载高分散催化中心提供了天然的物理空间;多孔结构促使催化剂与反应物充分接触;丰富的孔道有利于运输催化反应底物和产物,进而实现催化反应的高效进行.特别是离子液体片段的引入,可以作为催化活性中心的配体(稳定剂)或分散剂,同时能够有效改善MOFs和COFs材料孔道和活性中心周围的微环境.此外,还可以充分利用离子液体片段在适当的反应条件下转化为氮杂环卡宾配体的特点,在MOFs和COFs材料中引入氮杂环卡宾有机金属配合物.因此,我们对近几年来离子液体功能化的MOFs或COFs催化体系在CO_(2)环加成、CO_(2)还原功能化应用、CC偶联、羰基化以及其它有机转化反应的研究应用进行了简要综述,并对复合材料在催化领域的发展进行了总结和展望.

钯-膦-酸体系催化烯烃氢酯基化反应研究进展

烯烃氢酯基化反应是羰基合成领域的重要分支之一,长期以来一直备受关注.目前已发展了钯基、铑基、钴基、钌基等众多催化体系,其中钯-膦-酸催化体系因具有反应条件温和、底物普适性良好、催化性能优异等优点而得到最广泛、最深入的研究.因此,我们对均相、非均相的钯-膦-酸催化体系在烯烃氢酯基化反应中的研究应用进行了综述,并对催化机理、催化剂组成和性能进行了讨论,最后指出稳定性高、可回收性好的非均相钯-膦-酸催化体系将是该领域的研究重点.

Analysis of isolation of cerebral cortical neurons in rats by different methods

The aim of this study was to find a way to efficiently separate neuronal cells from the cerebral cortex of adult rats,providing a reference method for rapid acquisition of neuronal cells from the adult rat brain.Fifteen SD rats were randomly divided into three groups,with five SD rats in each group.Then,neuron cells were isolated from the adult rat cerebral cortex by the grinding method,the trypsin method,and the collagenase II method,respectively.The expression of anti-NeuN in the neurons of each group was analyzed by flow cytometry.The acquisition rates and morphology of neurons of each group were observed by immunofluorescence staining.The grinding or collagenase II method is more suitable for rapid acquisition of neuronal cells from an adult rat’s cerebral cortex.The number of neuron cells obtained by the trypsin method were very few,so it is not convenient for later experiments.

Preparation of Semisolid Slurry for Stainless Steel 1Cr18Ni9Ti

The controlled runout table cooling is essential in determining the final mechanical properties and flatness of steel strip. The heat of a hot steel strip is mainly extracted by cooling water during runout. In order to study the heat transfer by water jet impingement boiling during runout,a pilot facility was constructed at the University of British Columbia. On this pilot facility,the water jet impingement tests were carried out under various cooling conditions to investigate the effect of processing parameters,such as cooling water temperature,water jet impingement velocity,initial strip temperature,water flow rate,water nozzle diameter and array of water nozzles,on the heat transfer of heated strip. The results obtained contribute to the optimization of cooling water during runout.

新一代水性单组分丙烯酸乳液在高性能抗渗色水性木器封闭底漆中的应用研究

重点介绍了水性抗渗色封闭底漆的设计思路,并通过实验表明,开发的新一代水性单组分丙烯酸乳液。具有致密的成膜性能,能有效阻隔单宁等有色物质的渗出,并且在此基础上可添加抗渗色助剂,在保证配方稳定性和施工性能的同时,进一步提高水性封闭底漆的抗渗色功能。

Aptamer-Based Cell-Surface Profiling with Single-Cell Resolution Enables Precise Cancer Characterization

Molecular profiling of cell-surface proteins is a powerful strategy for precise cancer diagnosis.While mass cytometry(MC)enables synchronous detection of over 40 cellular parameters,its full potential in disease classification is challenged by the limited types of recognition probes currently available.In this work,we synthesize a panel of heavy isotopeconjugated aptamers to profile cancer-associated signatures on the surface of hematological malignancy(HM)cells.Based on 15 molecular signatures,we performed cell-surface profiling that allowed the precise classification of 8 HM cell lines.Combined with machine-learning technology,this aptamer-based MC platform also achieved multiclass identification of HM subtypes in clinical sampleswith 100%accuracy in the training cohort and 80%accuracy in the test cohort.Therefore,we report an effective and practical strategy for precise cancer classification at the singlecell level,paving the way for its clinical use in the near future.

Trans-synaptic Neural Circuit-Tracing with Neurotropic Viruses

A central objective in deciphering the nervous system in health and disease is to define the connections of neurons. The propensity of neurotropic viruses to spread among synaptically-linked neurons makes them ideal for mapping neural circuits. So far, several classes of viral neuronal tracers have become available and provide a powerful toolbox for delineating neural networks. In this paper, we review the recent developments of neurotropic viral tracers and highlight their unique properties in revealing patterns of neuronal connections.

Evaluating the flavor and divergent bacterial communities in corn-based zha-chili

Zha-chili is a naturally fermented traditional food from central southern China.Corn-based zha-chili is one of the most popular varieties with a special flavor.To investigate its distinct microbiome,corn-based zha-chili samples were collected and investigated using both high-throughput sequencing and culture-dependent method.Subsequently,E-nose and E-tongue sensors were used to evaluate the overall sensory profile.We found that the bacterial communities present in zha-chili samples from the two regions were significantly different(P<0.05).Companilactobacillus,Lactiplantibacillus,and Corynebacterium were found to be the dominant genera common to samples from both regions.Among these,lactic acid bacteria were the most dominant.Biomarker genera were Ligilactobacillus,Lactobacillus,and Levilactobacillus(Huaihua)and Pantoea,Lactiplantibacillus,and Weissella(Songtao).Using culture-dependent methods,the most dominant genus Companilactobacillus was found to comprise Companilactobacillus alimentarius and Companilactobacillus futsaii.The sensory profile was also characterized.This indicated that zha-chili from the two regions could be discriminated by sourness and aftertaste-B(E-taste),and W1C,W3C,W5C,W1S,W2S,W5S,and W2W(E-nose).Correlation analysis suggested that the dominant genera might not affect the aroma quality of corn-based zha-chili,whereas they were related to taste quality.Levilactobacillus and Ligilactobacillus were positively correlated with the characteristic taste indices and negatively correlated with the off-flavor indices.Another dominant genus,Kocuria was positively correlated with umami and richness(P<0.05).Our results could provide a basis for supporting zha-chili production and help the isolation of appropriate lactic acid bacteria from corn-based zha-chili.

Therapeutic silencing miR-146b-5p improves cardiac remodeling in a porcine model of myocardial infarction by modulating the wound reparative phenotype

Fibrotic remodeling is an adverse consequence of immune response-driven phenotypic modulation of cardiac cells following myocardial infarction(Ml).MicroRNA-146b(miR-146b)is an active regulator of immunomodulation,but its function in the cardiac inflammatory cascade and its clinical implication in fibrotic remodeling following Ml remain largely unknown.Herein,miR-146b-5p was found to be upregulated in the infarcted myocardium of mice and the serum of myocardial ischemia patients.Gain-and loss-of-function experiments demonstrated that miR-146b-5p was a hypoxia-induced regulator that governed the pro-fibrotic phenotype transition of cardiac cells.Overexpression of miR-146b-5p activated fibroblast proliferation,migration,and fibroblast-to-myofibroblast transition,impaired endothelial cell function and stress survival,and disturbed macrophage paracrine signaling.Interestingly,the opposite effects were observed when miR-146b-5p expression was inhibited.Luciferase assays and rescue studies demonstrated that the miR-146b-5p target genes mediating the above phenotypic modulations included interleukin 1 receptor associated kinase 1(IRAKI)and carcinoembryonic antigen related cell adhesion molecule 1(CEACAM1).Local delivery of a miR-146b-5p antagomir significantly reduced fibrosis and cell death,and upregulated capillary and reparative macrophages in the infarcted myocardium to restore cardiac remodeling and function in both mouse and porcine Ml models.Local inhibition of miR-146b-5p may represent a novel therapeutic approach to treat cardiac fibrotic remodeling and dysfunction following Ml.

Electron back-scattering diffraction preliminary analysis of heterogeneous nuclei in magnesium alloy during solidification process under GPa high pressure

The effective heterogeneous nuclei in Mg-7.92 Zn-1.70 Y alloy during solidification process under high pressure was investigated by EBSD. It is found that the orientation relationship between Mg matrix and MgY phase, [111]_（MgY）//[1210]_（α-Mg） and（101）_（MgY）//（0001）_（α-Mg）, exists between Mg matrix and MgY phase.The MgY phase is the potential heterogeneous nuclei substrate for a-Mg solidified under high pressure. It is calculated by Bramfitt mode that the mismatch between Mg matrix and MgY phase is greater than 12% under atmospheric pressure. When solidified under high pressure of 4 GPa, the solidification pressure can increase the number of the α-Mg nucleus by reducing the size of the nucleus, decreasing interfacial energy of MgY/a-Mg, and changing the wettability between MgY phase and α-Mg from non-wetting under atmospheric pressure to wetting under high pressure. The MgY phase becomes a powerful heterogeneous nuclei for α-Mg crystal. Increasing the number of valid heterogeneous nuclei substrate increases nucleus number and refines the grain of the alloy.

Insights into the dual-roles of alloying elements in the growth of Sn whiskers

The growth of Sn whiskers from Ti_(2)SnC/Sn-X(X=Sn,Bi,Pb,Ga)samples was studied in this work to understand the effect of alloying elements on whiskering behaviors.The mobility of source Sn atoms relating with the formation and migration of defects was found to be the critical factor dominating the growth rate,with the gathering of which to grow whiskers on the surface acts as an effective means to lower the enthalpy.As a result,the source Sn atoms would migrate to whisker root spontaneously,making the growth of whiskers the nature of materials,and external factors like compressive stress or oxidation are no more necessary but facilitate the whiskering process by promoting the mobility of source Sn atoms.

Phononic origin of structural lubrication

Atomistic mechanisms of frictional energy dissipation have attracted significant attention.However,the dynamics of phonon excitation and dissipation remain elusive for many friction processes.Through systematic fast Fourier transform(FFT)analyses of the frictional signals as a silicon tip sliding over a graphite surface at different angles and velocities,we experimentally demonstrate that friction mainly excites non-equilibrium phonons at the washboard frequency and its harmonics.Using molecular dynamics(MD)simulations,we further disclose the phononic origin of structural lubrication,i.e.,the drastic reduction of friction force as the contact angle between two commensurate surfaces changes.In commensurate contacting states,friction excites a large amount of phonons at the washboard frequency and many orders of its harmonics that perfectly match each other in the sliding tip and substrate,while for incommensurate cases,only limited phonons are generated at mismatched washboard frequencies and few low order harmonics in the tip and substrate.

直接应用生物质固废的双基竖炉新工艺

简要说明了现有煤基直接还原工艺和气基直接还原工艺存在的主要问题,说明了直接应用生物质固废双基竖炉新工艺的工艺流程、主要工艺参数和原料条件等方面的技术特点,重点说明了该工艺的技术优势,也分析了该工艺需要解决的主要技术问题。