d-Orbital steered FeN_(4)moiety through N,S dual-site adjustation for zinc-air flow battery

The implementation of pristine covalent organic polymer(CO_(2)P)with well-defined structure as air electrode may spark fresh vitality to rechargeable zinc-air flow batteries(ZAFBs),but it still remains challenges in synergistically regulating their electronic states and structural porosity for the great device performance.Here,we conquer these issues by exploiting N and S co-doped graphene with COP rich in metal-ligand nitrogen to synergistically construct an effective catalyst for oxygen reduction reaction(ORR).Among them,the N and S co-doped sites with high electronegativity properties alter the number of electron occupations in the d orbital of the iron centre and form electron-transfer bridges,thereby boosting the selectivity of the ORR-catalysed four-electron pathway.Meanwhile,the introduction of COP materials aids the formation of pore interstices in the graphene lamellae,which both adequately expose the active sites and facilitate the transport of reactive substances.Benefiting from the synergistic effect,as-prepared catalyst exhibits excellent half-wave potentials(E_(1/2)=912 mV)and stability(merely 8.8%drop after a long-term durability test of 50000 s).Further,ZAFBs assembled with the N/SG@CO_(2)P catalyst demonstrate exceptional power density(163.8 mW cm^(-2))and continuous charge and discharge for approximately 140 h at 10 mA cm^(-2),outperforming the noble-metal benchmarks.

Structure optimization of connection frames based on frequency sensitivity in macro-micro motion platforms

High-performance connection frames are of great significance for ultra-high acceleration and ultra-precision positioning in macro-micro motion platforms. This paper first takes the connection frame as a research object,builds a finite element model(FEM) of the natural frequency of the frame, and then verifies the correctness of this model. The frequency sensitivity method is then used to perturb the structural parameters of the FEM of the connection frame, and the sensitivities of the first-order natural frequency and mass of the corresponding structural parameters are obtained by calculation and analysis. The design variables are also determined. The natural frequency is used as the optimization objective, and the design parameters and mass of the connection frame are constrained. The structural parameters of the connecting frame are obtained through optimization, and the model is built and verified by experiments. The results show that the first-order natural frequency of the connecting frame is effectively improved by the frequency sensitivity method, avoids resonance between the connecting frame and the voice coil motor, and realizes the lightweight design of the connection frame. This research provides a reliable basis for the stable operation and ultra-precision positioning of ultra-high acceleration macro-motion platforms.

Isoflavone Attenuates the Nuclear Transcription Factor Kappa B (NF-<i>κ</i>B) Activation on MPP⁺-Induced Apoptosis of PC12 Cells

Objective: To explore the underlying molecular mechanisms of cellular response to the challenge by 1-methyl-4-phenylpyridinium (MPP+)-induced apoptosis of PC12 cells, an in vitro cell model for Parkinson’s disease, and the effect of NF-κB activation on the protection of Parkinson’s disease by Isoflavone (I). Methods: PC12 cells were used to establish the cell model of Parkinson’s disease, and are divided into five groups: control group;MPP+ group;I (Isoflavone) + MPP+ group;I group;SN-50 + MPP+ group. The content of NF-κB in PC12 cells was determined by immunocytochemistry;The viability of PC12 cells after treated with cell-permeable NF-κB inhibitor SN-50 and cell viability were measured by MTT assay;the expression levels of NF-κB p65 in cytoplasm and nuclear fractions were evaluated by western blot analysis;the mRNA expression of NF-κB p65 was analyzed by in situ hybridization (ISH). Results: Compared with the control group, the protein of NF-κB p65 both in cytoplasm and in nuclei was significantly higher than in I + MPP+ and MPP+ groups;similarly, the mRNA expression level of NF-κB p65 gene was also significantly higher;moreover, the protein expression of NF-κB p65 was much lower in I group (P + group, the protein of NF-κB p65 was significantly lower in I + MPP+ group, the mRNA expression level of NF-κB p65 gene was also significantly lower, and the protein expression level of NF-κB p65 was much lower in I + MPP+ group (P + group (P > 0.05). Conclusion: NF-κB activation is essential to MPP+-induced apoptosis in PC12 cells;but Isoflavone can inhibit the cell damage to some extent to execute its protective function, which may be involved in nigral neurodegeneration in patients with Parkinson’s disease.

Combination of Astragalus membranaceus and Euonymus alatus (THUNB.) SIEB. for treatment of diabetes: A network-based pharmacology research

Objective:To find the target genes in combination of astragalus root(Astragalus membranaceus)and spindle tree wings(Euonymus alatus(THUNB.)SIEB.)(Qijian Heji)with the function of regulating blood glucose levels in kk mice by real-time fluorescence quantitative PCR(RT-PCR).To achieve the primary exploration on the material basis for Qijian Heji to improve the blood glucose levels of type 2 diabetic kk mice.Methods:We applied RT-PCR to detecting the expression of gene targets in kidney tissues of type 2 diabetes model kk mice.The detected gene targets were predicted by the network pharmacology method in the early stage of the project.Through the observation of the hypoglycemic effect of different ratios of Qijian Heji,the optimal proportion was determined and then used to conduct research of material basis.Results:Continuous administration of Qijian Heji(astragalus root:spindle tree wings Z 3:1)for six weeks resulted in significantly lowering blood glucose levels in mice in the fourth week,dropping from 33.3 to 21.9 mmol/L;this lower level was maintained in the fifth to sixth weeks.Blood glucose values in the positive drug group decreased from 33.3 to 21.85 mmol/L in the fourth week and maintained steady decreasing in the fifth and sixth weeks.Conclusion:Qijian Heji,with proportion of 3:1,could significantly reduce the blood glucose values in kk mice,animal experiment results verified the accurate prediction of network pharmacology,and at the same time,it is verified there was a certain therapeutic effect about the combination of the two herbs on reducing the glucose value.Animal experiments and RT-PCR results showed that Qijian Heji conducted a hypoglycemic effect by modulating estrogen receptor(ESR1)and renin(REN)expression.

构建青少年化学科普活动内容分级素材库

在收集和分析常见化学类科普素材的基础上,通过整合素材内容与科学教育体系的对应关系,为化学教育和化学科普工作者搭建一个有实践参考价值的内容分级素材库。本研究着眼新时期社会发展的政策导向和现实需求,旨在为青少年化学类科普活动的具体实践提供一种框架性和建设性的新视角。

化学教育走进雄安——白洋淀环保主题暑期实践活动

在京津冀一体化、雄安新区建设和“绿水青山就是金山银山”生态文明思想的三大政策背景下,由首都师范大学化学(师范)专业师生组成的京冀科育团队于2019年暑假走进雄安新区,以化学教育为核心、以环境保护为主题、以提升学科核心素养为导向,开展了兼具化学专业特色和教师教育特色的暑期实践活动。

A Mass Transfer-Enhanced Pyrolysis-Free Bifunctional Catalyst to Boost Ultralong Lifespan Zinc-Air Batteries

The development of efficient and low-cost bifunctional oxygen catalysts is essential yet a challenge for zinc-air batteries(ZABs).Here,we prepared a pyrolysis-free 3-dimensional hybrid catalyst(COP-Fe@3DLDH)with bifunctional oxygen-catalytic activity by integrating layered double hydroxides(3D-LDH)and a fully conjugated iron phthalocyanine-based covalent organic polymer(COP-Fe).More hierarchically porous and larger specific surface area(170.4 m^(2) g^(−1))can effectively enhance the mass transfer process and active site exposure of cathode,allowing COP-Fe@3D-LDH to exhibit an outstanding peak power density(148.5 mW cm^(-2))and an ultralong lifespan(over 400 h at 10 mA cm^(-2))in ZABs.Accordingly,this work provides a new perspective to enhance the performance of pyrolysis-free catalysts in ZABs.

补肾益精方对外周血干细胞在RCS大鼠视网膜上的募集及睫状神经营养因子表达的影响

目的:观察补肾益精方对外周血骨髓间充质干细胞在视网膜变性模型(RCS)大鼠视网膜募集及睫状神经营养因子(CNTF)分泌的影响,探讨补肾益精方治疗视网膜退行性病变的作用机制。方法:实验研究。采用尾静脉注射方式将1×107个GFP标记的骨髓间充质干细胞(GFP-MSCs)注射至3周龄RCS大鼠外周血,然后按随机数字表法分为蒸馏水组及补肾益精方(BSYJ)组,每组39只。注射后第1天开始分别采用蒸馏水及补肾益精方药液灌胃,正常SD大鼠作为对照组常规饲养。给药7d、14d及28d时分别采用视网膜铺片、免疫荧光显微镜观察GFP-MSCs在视网膜的募集情况;实时荧光定量PCR及免疫荧光双染技术检测视网膜表达CNTF的情况;TUNEL法检测视网膜细胞凋亡情况;采用单因素方差进行数据分析。结果:给药7d、14d和28d时,蒸馏水组GFP-MSCs的数目少于BSYJ组,其中给药28d时,2组差异有统计学意义(t=2.71,P=0.001)。给药7d、14d和28d时,BSYJ组CNTF表达较蒸馏水组均明显增加,3组差异有统计学意义(F=5.763,P=0.003;F=3.165,P=0.042;F=4.839,P=0.004)。给药7d和28d时,BSYJ组视网膜细胞凋亡率明显少于蒸馏水组,3组差异有统计学意义(F=0.002,P=0.001;F=0.307,P=0.004)。结论:补肾益精方能够促进外周血干细胞在视网膜上的募集以及促进CNTF的表达,这可能是补肾益精方延缓RCS大鼠视网膜细胞凋亡和病变进程的作用机制之一。

Electron donor–acceptor (D-A) tuning to achieve soluble covalent organic polymers for optoelectronic devices

Covalent organic polymers(COPs)have emerged as a unique class of luminescent polymers with pre-designed quasi-ordered architectures.However,their layered stacks and limited solubility preclude further processing for large-scale applications in devices,especially optoelectronic equipment.Herein,a universal strategy to adjust the electron donor–acceptor(D-A)moieties of the building blocks in COPs is proposed,achieved by in situ charge exfoliation of COP blocks into few-layer true solutions in(Lewis)acid and base media.The electron D-A moieties of the building blocks endow the COPs with the ability to accept or donate electrons,by altering the electron cloud distribution as well as the relative energy levels of the frontier molecular orbitals.The resultant soluble COPs can easily be processed into a uniform film by solution processing via the spin-coat method.The obtained COP-N achieves efficient and stable perovskite electroluminescence as a novel hole injection material on indium tin oxide,and the operating lifetime for a perovskite quantum dot light-emitting diodes device exceeds that of a poly(ethylene dioxythiophene):polystyrene sulphonate counterpart.This straightforward electronic regulation strategy provides a new avenue for the rational synthesis of processable reticular molecular polymers for practical electronic devices.

石栗叶绿体基因组研究

石栗(Aleurites moluccana)是大戟科石栗属的常绿阔叶乔木,具有能源、药用和观赏价值。为填补石栗叶绿体基因组研究的空白,通过二代高通量全基因组测序,组装和注释了石栗叶绿体基因组,并进行基因组特征和系统发育分析。结果显示,石栗叶绿体基因组为典型的四段式结构,总长度为163298 bp,LSC、SSC及IR的长度分别为91301、18501和26748bp。石栗叶绿体基因组共有131个基因,包括8个rRNA基因,37个tRNA基因,86个蛋白质编码基因。研究发现145个SSR位点,检测到重复单元有单核苷酸、二核苷酸、三核苷酸和四核苷酸,数目分别为80、53、10和2个。共线性分析结果表明,石栗叶绿体基因组存在基因倒位和重排现象。利用最大似然法和贝叶斯法构建了系统发育树,显示石栗与油桐(Vernicia fordii)和东京桐(Deutzianthus tonkinensis)亲缘关系较近,并形成姐妹群。利用化石时间进行定年分析,表明石栗属、油桐属和东京桐属的分化时间为25.94 Ma(95%HPD:24.71–63.32 Ma)。该研究丰富了石栗基因组信息,可为石栗种质资源的开发利用提供基础遗传数据,同时为石栗属物种鉴定及系统发育研究提供参考。

Nutrient uptake,physiological responses and growth of tobacco(Nicotiana tabacum L.)in soil under composite salt stress

High soil salinity imposes osmotic stress and ion toxicity in plants,leading to substantial crop yield loss worldwide.Understanding of the quantitative and dynamic physiological responses to composite soil salt stress is limited and needs to be expanded.In this study,physiological,nutritional,and biomass yield parameters of tobacco(Nicotiana tabacum L.)grown in soil with five levels of composite soil salinity(CSS),basal CSS level(control,CK)and 3(T_(1)),6(T_(2)),9(T_(3)),and 12(T_(4))times the basal CSS level,under greenhouse were determined at days 30,60,and 90 after transplanting.Leaf dry biomass significantly(P<0.05)increased at the low salinity levels applied(T_(1) and T_(2))at all three time points,whereas it progressively declined as the CSS level further increased.The leaf physiological and photosynthetic responses were more adversely affected by CSS at the early growth stage(day 30).A path coefficient analysis demonstrated that leaf proline content had the largest direct effect(-0.66),and leaf Cu content had the most significant indirect effect(0.49)on leaf dry biomass of plants.The results suggest that lower CSS levels(T_(1) and T_(2))could stimulate tobacco growth(leaf biomass yield,in particular),and higher leaf proline and Cu levels at the early growth stage may potentially increase the ability of tobacco plants to withstand the adverse effects of salinity,which could be considered for future research and development of salinity management strategies.