Motor neuron-specific RhoA knockout delays degeneration and promotes regeneration of dendrites in spinal ventral horn after brachial plexus injury

Dendrites play irreplaceable roles in the nerve conduction pathway and are vulnerable to various insults.Peripheral axotomy of motor neurons results in the retraction of dendritic arbors,and the dendritic arbor can be re-expanded when reinnervation is allowed.RhoA is a target that regulates the cytoskeleton and promotes neuronal survival and axon regeneration.However,the role of RhoA in dendrite degeneration and regeneration is unknown.In this study,we explored the potential role of RhoA in dendrites.A line of motor neuronal conditional knockout mice was developed by crossbreeding HB9~(Cre+)mice with RhoA~(flox/flox)mice.We established two models for assaying dendrite degeneration and regeneration,in which the brachial plexus was transection or crush injured,respectively.We found that at 28 days after brachial plexus transection,the density,complexity,and structural integrity of dendrites in the ventral horn of the spinal cord of RhoA conditional knockout mice were slightly decreased compared with that in Cre mice.Dendrites underwent degeneration at 7 and 14 days after brachial plexus transection and recovered at 28–56 days.The density,complexity,and structural integrity of dendrites in the ventral horn of the spinal cord of RhoA conditional knockout mice recovered compared with results in Cre mice.These findings suggest that RhoA knockout in motor neurons attenuates dendrite degeneration and promotes dendrite regeneration after peripheral nerve injury.

The interaction between temperature and precipitation on the potential distribution range of Betula ermanii in the alpine treeline ecotone on the Changbai Mountain

Alpine treeline ecotones are highly sensitive to climate warming.The low temperature-determined alpine treeline is expected to shift upwards in response to global warming.However,little is known about how temperature interacts with other important factors to influence the distribution range of tree species within and beyond the alpine treeline ecotone.Hence,we used a GF-2 satellite image,along with bioclimatic and topographic variables,to develop an ensemble suitable habitat model based on the species distribution modeling algorithms in Biomod2.We investigated the distribution of suitable habitats for B.ermanii under three climate change scenarios(i.e.,low(SSP126),moderate(SSP370)and extreme(SSP585)future emission trajectories)between two consecutive time periods(i.e.,current-2055,and 2055-2085).By 2055,the potential distribution range of B.ermanii will expand under all three climate scenarios.The medium and high suitable areas will decline under SSP370 and SSP585scenarios from 2055 to 2085.Moreover,under the three climate scenarios,the uppermost altitudes of low suitable habitat will rise to 2,329 m a.s.l.,while the altitudes of medium and high suitable habitats will fall to 2,201 and2,051 m a.s.l.by 2085,respectively.Warming promotes the expansion of B.ermanii distribution range in Changbai Mountain,and this expansion will be modified by precipitation as climate warming continues.This interaction between temperature and precipitation plays a significant role in shaping the potential distribution range of B.ermanii in the alpine treeline ecotone.This study reveals the link between environmental factors,habitat distribution,and species distribution in the alpine treeline ecotone,providing valuable insights into the impacts of climate change on high-elevation vegetation,and contributing to mountain biodiversity conservation and sustainable development.

State-selective charge exchange cross sections in collisions of highly-charged sulfur ions with helium and molecular hydrogen

The state-selective cross section data are useful for understanding and modeling the x-ray emission in celestial observations.In the present work,using the cold target recoil ion momentum spectroscopy,for the first time we investigated the state-selective single electron capture processes for S^(q+)–He and H_(2)(q=11–15)collision systems at an impact energy of q×20 keV and obtained the relative state-selective cross sections.The results indicate that only a few principal quantum states of the projectile energy level are populated in a single electron capture process.In particular,the increase of the projectile charge state leads to the population of the states with higher principal quantum numbers.It is also shown that the experimental averaged n-shell populations are reproduced well by the over-barrier model.The database is openly available in Science Data Bank at 10.57760/sciencedb.j00113.00091.

绝对硬度的量化探究——介绍一个计算化学实验

介绍了利用Gaussian软件定量研究软硬酸碱中化合物硬度的实验设计,涉及化合物的构型优化和高精度单点能计算。旨在通过本实验,学生能够初步掌握运用量子化学计算绝对硬度的基本步骤,加深对软硬酸碱理论的理解,为今后从事相关科研工作打下基础。

疫情期间全球空气质量变化:臭氧响应的区域间差异

疫情期间全球各地一次排放大幅削减,而臭氧等二次污染的响应则存在着区域间差异.结合地面和卫星观测发现,同在氮氧化物大幅下降的情况下,臭氧在东亚和欧洲呈现出可达14ppb的上升信号,而北美则下降为主(约2–4ppb).我们结合气象分析和臭氧敏感性进一步讨论了臭氧响应差异性的原因,一方面受臭氧与前体物间关系的影响;另一方面来自于气象,尤其是温度.研究明晰了人为排放,化学和气象三者的内在关联,强调了在臭氧控制过程中考虑前体物削减和气象条件协同的重要性.

第33届江苏省化学竞赛选拔赛有机试题解析

详尽讨论了第33届中国化学奥林匹克竞赛(江苏赛区)夏令营暨选拔赛考试有机化学部分试题,并进行了多方面的拓展。同时采用计算化学方法辅助教学,供指导老师和参赛选手进行参考。

Role of microtubule dynamics in Wallerian degeneration and nerve regeneration after peripheral nerve injury

Wallerian degeneration,the progressive disintegration of distal axons and myelin that occurs after peripheral nerve injury,is essential for creating a permissive microenvironment for nerve regeneration,and involves cytoskeletal reconstruction.However,it is unclear whether microtubule dynamics play a role in this process.To address this,we treated cultured sciatic nerve explants,an in vitro model of Wallerian degeneration,with the microtubule-targeting agents paclitaxel and nocodazole.We found that paclitaxel-induced microtubule stabilization promoted axon and myelin degeneration and Schwann cell dedifferentiation,whereas nocodazole-induced microtubule destabilization inhibited these processes.Evaluation of an in vivo model of peripheral nerve injury showed that treatment with paclitaxel or nocodazole accelerated or attenuated axonal regeneration,as well as functional recovery of nerve conduction and target muscle and motor behavior,respectively.These results suggest that microtubule dynamics participate in peripheral nerve regeneration after injury by affecting Wallerian degeneration.This study was approved by the Animal Care and Use Committee of Southern Medical University,China(approval No.SMUL2015081) on October 15,2015.

重组人血管内皮抑制素逆转人肺腺癌A549/DDP细胞顺铂耐药性的研究(英文)

Objective: Recombinant human Endostatin(rh-Endostatin, YH-16) can reverse cisplatin resistance in A549/DDP cells. However, the possible effect of rh-Endostatin in reversing DDP-resistance in A549/DDP cells and the mechanism are needed to be investigated. Methods: Lung adenocarcinoma cell line A549 and its DDP-resistant cell line A549/DDP were treated with DDP and/or recombinant human Endostatin. Difference in drug resistance was analyzed between different regimens and between different cell lines after a 72 h-treatment in vitro. And below the non-cytotoxic concentration of rh-Endostatin, the possibility of rh-Endostatin in reversing DDP-resistance in A549/DDP was evaluated. The resistance protein which was detected in the study included P glycoprotein(P-gp) and topoisomerase II(Topo-II). Results: Rh-Endostatin below 400 μg/mL showed no cytotoxicity in either A549 or A549/DDP after 72 h-treatment with it. The inhibited concentration of 50%(IC50) observed for DDP was(0.79 ± 0.05) μg/mL in A549 and(13.2 ± 1.1) in A549/DDP respectively. IC50 was reduced to 2.57 ± 0.05 μg/mL in A549/DDP treated by rh-Endostatin below the non-cytotoxic concentrations in combination with DDP, with a reversal fold(RF) of 5.14 and a relative reversal rate of 85.6%. Apoptotic rates were 2.01%, 13.47% and 29.26% respectively for cells treated with rh-Endostain, DDP, and the combination. The rate of the A549/DDP control group was 0.99%. The expression level of P-gp or Topo-II was higher in A549/DDP cells than in A549 cells. Rh-Endostatin may partially reverse DDP-resistance in A549/DDP cells in vitro, with a probable mechanism related to lowering expression of P-gp and Topo-II. Conclusion: Rh-Endostatin of non-cytotoxic dose partially reversed cisplatin resistance in cisplatin-resistant human lung adenocarcinoma cell line A549/DDP. Rh-Endostatin reversed the resistance of A549/DDP cells to DDP, which may be related to decreased protein expression of P-gp and Topo-II in A549/DDP cells.

一个新的胃癌预后记分(英文)

Objective:The lack of a simple criterion for gastric carcinoma creates a persistent challenge for clinicians trying to provide patients with useful prognostic information.The aim of this study was to identify baseline prognostic factors,and use this information to establish a simple criterion to predict outcome in gastric carcinoma.Methods:Between 2005 and 2010, 155 patients with gastric carcinoma,were enrolled.Clinicopathologic prognostic factors were evaluated by univariate and multivariate analysis.Results:Of the 155 patients,48(30.9%)died.Three independent poor prognostic factors were identified by multivariate analysis:gross type>or=3(hazard ratio[HR],1.564;95%CI,1.067 to 2.294),peritoneal dissemination (HR,3.750;95%CI,1.760 to 7.989)and lymphatic duct invasion(HR,3.578;95%CI,1.422 to 9.004).One point was added for each category among three independent prognostic factors.Prognostic score(PS)was determined by an aggregate of these points for each category.There existed a significant difference between survival of patients with PS 0 or 1 and 2(P< 0.0001).Conclusion:Three poor prognostic factors were identified and a simple criteria was devised.Information from this analysis can be used to predict prognosis of gastric carcinoma with a strict stratification.

Ru-Ni alloy nanosheets as tandem catalysts for electrochemical reduction of nitrate to ammonia

Developing electrocatalysts that exhibit both high activity and ammonia selectivity for nitrate reduction is a significant and demanding challenge,primarily due to the complex nature of the multiple-electron reduction process involved.An encouraging approach involves coupling highly active precious metals with transition metals to enhance catalytic performance through synergy.Here,we report a ruthenium-nickel alloy catalyst with nanosheets(Ru-Ni NSs)structure that achieves a remarkable ammonia Faradaic efficiency of approximately 95.93%,alongside a yield rate of up to 6.11 g·h^(−1)·cm^(−2).Moreover,the prepared Ru-Ni NSs exhibit exceptional stability during continuous nitrate reduction in a flow reactor for 100 h,maintaining a Faradaic efficiency of approximately 90%and an ammonia yield of 37.4 mg·L^(−1)·h^(−1)using 0.05 M nitrate alkaline electrolyte.Mechanistic studies reveal that the catalytic process follows a two-step pathway,in which HONO serves as a migration intermediate.The presence of a partially oxidized Ru(002)surface enhances the adsorption of nitrate and facilitates the release of the migration intermediate by adjusting the strength of the electrostatic and covalent interactions between the adsorbate and the surface,respectively.On the other hand,the Ni(111)surface promotes the utilization of the migration intermediate and requires less energy for NH_(3)desorption.This tandem process contributes to a high catalytic activity of Ru-Ni NSs towards nitrate reduction.

Dynamic DNA 5-hydroxylmethylcytosine and RNA 5-methycytosine Reprogramming During Early Human Development

After implantation,complex and highly specialized molecular events render functionally distinct organ formation,whereas how the epigenome shapes organ-specific development remains to be fully elucidated.Here,nano-hmC-Seal,RNA bisulfite sequencing(RNA-BisSeq),and RNA sequencing(RNA-Seq)were performed,and the first multilayer landscapes of DNA 5-hydroxymethylcytosine(5hmC)and RNA 5-methylcytosine(m^(5)C)epigenomes were obtained in the heart,kidney,liver,and lung of the human foetuses at 13-28 weeks with 123 samples in total.We identified 70,091 and 503 organ-and stage-specific differentially hydroxymethylated regions(DhMRs)and m^(5)C-modified mRNAs,respectively.The key transcription factors(TFs),T-box transcription factor 20(TBX20),paired box 8(PAX8),krueppel-like factor 1(KLF1),transcription factor 21(TCF21),and CCAAT enhancer binding protein beta(CEBPB),specifically contribute to the formation of distinct organs at different stages.Additionally,5hmC-enriched Alu elements may participate in the regulation of expression of TF-targeted genes.Our integrated studies reveal a putative essential link between DNA modification and RNA methylation,and illustrate the epigenetic maps during human foetal organogenesis,which provide a foundation for an in-depth understanding of the epigenetic mechanisms underlying early development and birth defects.

MXene(Ti2NTx)材料合成、表征、及作为热光开关用于全光波长调谐激光器

具有良好单色性的可调谐光纤激光器是密集波分复用传输系统中的关键组件.传统的调制方法难与全光通信网络兼容.本文中,我们利用MXene(Ti2NTx)的强光热效应,对基于迈克尔逊干涉仪的全光波长调谐光纤激光器进行了研究.对于全光调制器来说,信号光的相移,随控制光功率具有0.03πm W-1的线性关系.获得25 d B的调制深度,有利于提高调制器的灵敏度以实现快速的波长扫描.另外,实现的全光波长调谐激光器具有大边模抑制比,宽波长调谐范围和窄3-dB光谱宽度.这种新颖的基于Ti2NTx的全光波长调谐器不仅扩展了全光调制器的应用领域,而且也为基于Ti2NTx的异质结构提供了可扩展的可用性,以构建高性能的全光纤激光器.

Preparation of a tantalum-based MoSi_(2)–Mo coating resistant to ultra-high-temperature thermal shock by a new two-step process

To develop an ultra-high-temperature resistant coating for a reusable thermal protection system,the preparation of a tantalum-based MoSi_(2)-Mo coating by a new two-step process of multi-arc ion plating and halide activated pack cementation is presented.The coating has a dense structure and is well compatible with the tantalum substrate,which can be thermally shocked from room temperature to 1750℃ for 360 cycles without failure.The mechanism of the coating’s excellent resistance to high-temperature thermal shocks is that a strong-binding gradient interface and a dense SiO_(2) oxide scale with good oxygen resistance are formed by the high-temperature self-diffusion of Si.

Co-culture of Schwann cells and endothelial cells for synergistically regulating dorsal root ganglion behavior on chitosan-based anisotropic topology for peripheral nerve regeneration

Background:Anisotropic topologies are known to regulate cell-oriented growth and induce cell differentiation,which is conducive to accelerating nerve regeneration,while co-culture of endothelial cells(ECs)and Schwann cells(SCs)can significantly promote the axon growth of dorsal root ganglion(DRG).However,the synergistic regulation of EC and SC co-culture of DRG behavior on anisotropic topologies is still rarely reported.The study aims to investigate the effect of anisotropic topology co-cultured with Schwann cells and endothelial cells on dorsal root ganglion behavior for promoting peripheral nerve regeneration.Methods:Chitosan/artemisia sphaerocephala(CS/AS)scaffolds with anisotropic topology were first prepared using micro-molding technology,and then the surface was modified with dopamine to facilitate cell adhesion and growth.The physical and chemical properties of the scaffolds were characterized through morphology,wettability,surface roughness and component variation.SCs and ECs were co-cultured with DRG cells on anisotropic topology scaffolds to evaluate the axon growth behavior.Results:Dopamine-modified topological CS/AS scaffolds had good hydrophilicity and provided an appropriate environment for cell growth.Cellular immunofluorescence showed that in contrast to DRG growth alone,co-culture of SCs and ECs could not only promote the growth of DRG axons,but also offered a stronger guidance for orientation growth of neurons,which could effectively prevent axons from tangling and knotting,and thus may significantly inhibit neurofibroma formation.Moreover,the co-culture of SCs and ECs could promote the release of nerve growth factor and vascular endothelial growth factor,and up-regulate genes relevant to cell proliferation,myelination and skeletal development via the PI3K-Akt,MAPK and cytokine and receptor chemokine pathways.Conclusions:The co-culture of SCs and ECs significantly improved the growth behavior of DRG on anisotropic topological scaffolds,which may provide an important basis for the development of nerve grafts in peripheral nerve regeneration.

Byzantine Fault-Tolerant Routing for Large-Scale Wireless Sensor Networks Based on Fast ECDSA

Wireless sensor networks are a favorite target of Byzantine malicious attackers because of their limited energy, low calculation capability, and dynamic topology, and other important characteristics. The Byzantine Generals Problem is one of the classical problems in the area of fault tolerance, and has wide application, especially in distributed databases and systems. There is a lot of research in agreement and replication techniques that tolerate Byzantine faults. However, most of this work is not suited to large-scale wireless sensor networks, due to its high computational complexity. By introducing Fast ECDSA(Elliptic Curve Digital Signature Algorithm), which can resist timing and energy attacks, and reduce the proportion of verifying signature algorithm to generating signature algorithm to 1.2 times, we propose a new Byzantine fault-tolerant routing algorithm for large-scale wireless sensor networks with double-level hierarchical architecture. In different levels, the algorithm runs different BFT protocols.Theory and simulation results have proved that this algorithm has high security and the number of communication rounds between clusters is reduced by 1/3, which balances the network load. At the same time, the application of Fast ECDSA improves the security level of the network without burdening it.

Tunable flexible artificial synapses:a new path toward a wearable electronic system

The flexible electronics has been deemed to be a promising approach to the wearable electronic systems.However,the mismatching between the existing flexible deices and the conventional computing paradigm results an impasse in this field.In this work,a new way to access to this goal is proposed by combining flexible devices and the neuromorphic architecture together.To achieve that,a high-performance flexible artificial synapse is created based on a carefully designed and optimized memristive transistor.The device exhibits high-performance which has near-linear non-volatile resistance change under 10,000 identical pulse signals within the 515%dynamic range,and has the energy consumption as low as 45 fJ per pulse.It also displays multiple synaptic plasticity features,which demonstrates its potential for real-time online learning.Besides,the adaptability by virtue of its threeterminal structure specifically contributes its improved uniformity,repeatability,and reduced power consumption.This work offers a very viable solution for the future wearable computing.

Simulation of performance of intermediate fluid vaporizer under wide operation conditions

The intermediate fluid vaporizer(IFV)is a typical vaporizer of liquefied natural gas(LNG),which in general consists of three shell-and-tube heat exchangers(an evaporator,a condenser,and a thermolator).LNG is heated by seawater and the intermediate fluid in these heat exchangers.A one-dimensional heat transfer model for IFV is established in this paper in order to investigate the influences of structure and operation parameters on the heat transfer performance.In the rated condition,it is suggested to reduce tube diameters appropriately to get a large total heat transfer coefficient and increase the tube number to ensure the sufficient heat transfer area.According to simulation results,although the IFV capacity is much larger than the simplified-IFV(SIFV)capacity,the mode of SIFV could be recommended in some low-load cases as well.In some cases at high loads exceeding the capacity of a single IFV,it is better to add an AAV or an SCV operating to the IFV than just to increase the mass flow rate of seawater in the IFV in LNG receiving terminals.

Influence of retinoic acid on TBX1 expression in myocardial cells induced by Shh and Fgf8

The aim of this study was to explore the regulatory mechanism of retinoic acid(RA)on the TBX1 gene expression in myocardial cells.Ventricular cardio-cytes were isolated from neonatal rats and cultured,and then treated with different concentrations of retinoic acid.The expression of Shh and Fgf8 at mRNA and protein levels in neonatal rat myocardial cells were measured by using RT-PCR and Western blot technique,respectively.There was basal expression of Shh and Fgf8 in the control group.When treated with 3�10–7 mol/L RA,we observed that the expression of Shh mRNA and protein in neonatal rat myocardial cells were up-regulated by 1.51(P<0.05)and 1.10 times(P<0.05),respectively.In comparison with the control group,under the concentra-tion of 5�10–7 mol/L RA,they were up-regulated by 2.21(P<0.05)and 2.38 times(P<0.05)individually.Mean-while,we could detect that the expression of Fgf8 mRNA and protein were up-regulated by 2.50 times(P<0.05)and 80%(P<0.05)separately compared with the control group after stimulation of 3�10–7 mol/L RA,and they were up-regulated by 3.48(P<0.05)and 2.04 times(P<0.05)individually after stimulation of 5�10–7 mol/L RA.The results indicated that RA could induce the expression of Shh and Fgf8 in neonatal rat myocardial cells.At the same time,it has shown that Shh and Fgf8 were involved in the regulation process of RA on TBX1 expression.

Lightweight Trusted Security for Emergency Communication Networks of Small Groups

Public communication infrastructures are susceptible to disasters. Thus, the Emergency Communication Networks(ECNs) of small groups are necessary to maintain real-time communication during disasters. Given that ECNs are self-built by users, the unavailability of infrastructures and the openness of wireless channels render them insecure. ECN security, however, is a rarely studied issue despite of its importance. Here, we propose a security scheme for the ECNs of small groups. Our scheme is based on the optimized Byzantine Generals’ Problem combined with the analysis of trusted security problems in ECNs. Applying the Byzantine Generals’ Problem to ECNs is a novel approach to realize two new functions, debugging and error correction, for ensuring system consistency and accuracy. Given the limitation of terminal devices, the lightweight fast ECDSA algorithm is introduced to guarantee the integrity and security of communication and the efficiency of the network. We implement a simulation to verify the feasibility of the algorithm after theoretical optimization.

An integrated epidemic modelling framework for the real-time forecast of COVID-19 outbreaks in current epicentres

Various studies have provided a wide variety of mathematical and statistical models for early epidemic prediction of the COVID-19 outbreaks in China's Mainland and other epicentres worldwide.In this paper,we present an integrated modelling framework,which incorporates typical exponential growth models,dynamic systems of compartmental models and statistical approaches,to depict the trends of COVID-19 spreading in 33 most heavily suffering countries.The dynamic system of SIR-X plays the main role for estimation and prediction of the epidemic trajectories showing the effectiveness of containment measures,while the other modelling approaches help determine the infectious period and the basic reproduction number.The modelling framework has reproduced the subexponential scaling law in the growth of confirmed cases and adequate fitting of empirical time-series data has facilitated the efficient forecast of the peak in the case counts of asymptomatic or unidentified infected individuals,the plateau that indicates the saturation at the end of the epidemic growth,as well as the number of daily positive cases for an extended period.