Nano-silica modified lightweight and high-toughness carbon fiber/phenolic ablator with excellent thermal insulation and ablation performance

Lightweight and high-toughness carbon fiber/phenolic ablator(CFPA)is required as the Thermal Protection System(TPS)material of aerospace vehicles for next-generation space missions.To improve the ablative properties,silica sol with good particle size distribution prepared using tetramethoxysilane(TMOS)was blended with natural rubber latex and deposited onto carbon fiber felt,which was then integrated with phenolic aerogel matrix,introducing nano-silica into the framework of CFPA.The modified CFPA with a low density of 0.28—0.31 g/cm3exhibits strain-in-fracture as high as 31.2%and thermal conductivity as low as 0.054 W/(m·K).Furthermore,a trace amount of nano-silica could effectively protect CFPA from erosion of oxidizing atmosphere in different high-temperature environments.The oxyacetylene ablation test of 3000°C for 20 s shows a mass ablation rate of 0.0225 g/s,a linear ablation rate of 0.209 mm/s for the modified CFPA,which are 9.64%and 24.82%lower than the unmodified one.Besides,the long-time butane ablation test of 1200°C for 200 s shows an insignificant recession with mass and linear ablation rate of 0.079 g/s and 0.039 mm/s,16.84%and 13.33%lower than the unmodified one.Meanwhile,the fixed thermocouple in the test also demonstrates a good thermal insulation performance with a low peak back-face temperature of 207.7°C,12.25%lower than the unmodified one.Therefore,the nano-silica modified CFPA with excellent overall performance presents promising prospects in high-temperature aerospace applications.

Lignans are the main active components of Schisandrae Chinensis Fructus for liver disease treatment:a review

As a traditional Chinese herbal medicine,Schisandrae Chinensis Fructus(SC)has been used in medicine and food industry due to its health care and therapeutic effects.Over the past 20 years,the use of SC and its active ingredient lignans in the prevention and treatment of liver diseases has been increasing,and their hepatoprotective effects has increased the interest of the public and academia.Therefore,in the present work,we first determined the effectiveness of SC in the treatment of liver diseases such as metabolic associated fatty liver disease,alcoholic liver disease,cholestatic liver disease and acute liver injury.Subsequently,the pharmacological effects and molecular mechanisms of lignans,the active components of SC,for liver disease treatment were comprehensively summarized for the first time.The results showed that the lignans in SC could achieve hepatoprotective effects by regulating lipid metabolism,anti-fibrosis,anti-inflammation,anti-oxidation,anti-tumor and regulating bile acid metabolism.The mechanism mainly involved adenosine 5’-monophosphate-activated protein kinase,endoplasmic reticulum stress,sterol regulatory element binding protein 1c,autophagy,transforming growth factor-β,mitogen-activated protein kinase,microRNA,nuclear factor kappa-B,nuclear factor erythroid-2-related factor 2,heat shock proteins and pregnane X receptor signaling pathways.These results can lay a scientific foundation for the development of hepatoprotective drugs or functional foods from SC/lignans.

Overcoming the Na-ion conductivity bottleneck for the cost-competitive chloride solid electrolytes

Chloride solid electrolytes possess multiple advantages for the construction of safe,energy-dense allsolid-state sodium batteries,but presently the chlorides with sufficiently high cost-competitiveness for commercialization almost all exhibit low Na-ion conductivities of around 10^(-5)S cm^(-1)or lower.Here,we report a chloride solid electrolyte,Na_(2.7)ZFCl_(5.3)O_(0.7),which reaches a Na-ion conductivity of 2.29×10^(-4)S cm^(-1)at 25℃without involving overly expensive raw materials such as rare-earth chlorides or Na_(2)S.In addition to the efficient ion transport,Na_(2.7)ZrCl_(5.3)O_(0.7)also shows an excellent deformability surpassing that of the widely studied Na_(3)PS_(4),Na_(3)SbS_(4),and Na_(2)ZrCl_(6)solid electrolytes.The combination of these advantages allows the all-solid-state cell based on Na_(2.7)ZrCl_(5.3)O_(0.7)and NaCrO_(2)to realize stable room-temperature cycling at a much higher specific current than those based on other non-viscoelastic chloride solid electrolytes in literature(120 mA g^(-1)vs.12-55 mA g^(-1));after 100 cycles at such a high rate,the Na_(2.7)ZFCl_(5.3)O_(0.7)-based cell can still deliver a discharge capacity of 80 mAh g^(-1)at25℃.

Manipulating selenium molecular configuration in N/O dual-doped porous carbon for high performance potassium-ion storage

Potassium-selenium(K-Se)batteries have attracted more and more attention because of their high theoretical specific capacity and natural abundance of K resources.However,dissolution of polyselenides,large volume expansion during cycling and low utilization of Se remain great challenges,leading to poor rate capability and cycle life.Herein,N/O dual-doped carbon nanofibers with interconnected micro/mesopores(MMCFs)are designed as hosts to manipulate Se molecular configuration for advanced flexible K-Se batteries.The micropores play a role in confining small Se molecule(Se_(2–3)),which could inhibit the formation of polyselenides and work as physical barrier to stabilize the cycle performance.While the mesopores can confine long-chain Se(Se_(4–7)),promising sufficient Se loading and contributing to higher discharge voltage of the whole Se@MMCFs composite.The N/O co-doping and the 3D interpenetrating nanostructure improve electrical conductivity and keep the structure integrity after cycling.The obtained Se_(2–3)/Se_(4–7)@MMCFs electrode exhibits an unprecedented cycle life(395 mA h g^(−1) at 1 A g^(−1) after 2000 cycles)and high specific energy density(400 Wh kg^(−1),nearly twice the specific energy density of the Se_(2–3)@MMCFs).This study offers a rational design for the realization of a high energy density and long cycle life chalcogen cathode for energy storage.

A new nonlinear photoconductive terahertz radiation source based on photon-activated charge domain quenched mode

We present a high-performance terahertz(THz)radiation source based on the photon-activated charge domain(PACD)quenched mode of GaAs photoconductive antennas(GaAs PCA).The THz radiation characteristics of the GaAs PCA under different operating modes are studied.Compared with the linear mode,the intensity of THz wave radiated by the GaAs PCA can be greatly enhanced due to the avalanche multiplication effect of carriers in the PACD quenched mode.The results show that when the carrier multiplication ratio is 16.92,the peak-to-peak value of THz field radiated in the PACD quenched mode increases by as much as about 4.19 times compared to the maximum values in the linear mode.

Reversibly Tuning Electrochemiluminescence with Stimulated Emission Route for Single-Cell Imaging

Electrochemiluminescence (ECL) has established itself as an excellent transduction technique in biosensing and light-emitting device, while conventional ECL mechanism depending on spontaneous emission of luminophores lacks reversibility and tunable emission characters, limiting the universality of ECL technique in the fields of fundamental research and clinical applications. Here, we report the first observation of stimulated emission route in ECL and thus establish a reversible tuning ECL microscopy for single-cell imaging. This microscopy uses a focused red-shifted beam to transfer spontaneous ECL into stimulated ECL, which enables selective and reversible tuning of ECL emission from homogeneous solution, single particles, and single cells. After excluding other possible competitive routes, the stimulated ECL emission route is confirmed by a dual-objective system in which the suppressed spontaneous ECL is accompanied by the enhanced stimulated ECL. By incorporating a commercial donut-shaped beam, the sharpness of single-cell matrix adhesion is improved 2 to 3 times compared with the counterpart in confocal ECL mode. The successful establishment of this stimulated emission ECL will greatly advance the development of light-emitting device and super-resolution ECL microscopy.

一种新型CO_(2)/原油助混剂CAA8-X的应用与助混机理

CO_(2)驱是一种具有广阔前景的提高油藏采收率的方法。其中,降低CO_(2)与原油的最低混相压力以实现混相驱是增强CO_(2)驱效果的重要手段。由此我们设计了由亲油基团十六烷基和亲CO_(2)基团全乙酰蔗糖酯基结合的新型“亲油-亲CO_(2)助混分子”十六酸全乙酰基蔗糖酯CAA8-X,研究发现,CAA8-X对超临界CO_(2)流体和不同油相的煤油、白油以及长庆原油有优异的助混效果,界面张力消失法和细管实验法测定结果表明,CAA8-X可以将超临界CO_(2)/长庆原油的最低混相压力降低20.5%。用分子动力学模拟计算了CO_(2)分子与全乙酰蔗糖酯基的亲和能力,研究了这类新型“亲油-亲CO_(2)助混分子”通过多酯头基降低与CO_(2)亲和势能而降低油/CO_(2)界面能的助混机理。

基于多酯头基的“油-二氧化碳两亲分子”设计及其助混规律

针对目前具有广泛应用的油相-超临界二氧化碳(scCO2)混合体系,我们提出了“油-CO2两亲分子”的概念,实验设计筛选出了一类以多酯头基作为亲CO2基团,长碳链作为亲油基团的油-CO2两亲分子。本工作以白油、煤油等为油相,以自主开发的可视化混相方法作为评价方式,以降低两相最低混相压力的助混效率为指标,系统研究了油-scCO2体系的助混规律。结果表明:(1)越多的酯基将提供越强的“亲CO2性”;(2)碳链长度为16的助混剂拥有最佳的助混效果;(3)与scCO2性质差异越大的油相,两亲分子的助混差异越明显,体现了油相种类带来的区分与拉平效应。本工作不仅将经典的水/油两亲分子概念扩展到油-scCO2两亲体系,对于实际生产中scCO2驱油也具有重要的指导意义。

4-(Benzylamino)formoyldiphenylammonium Triflate (BDPAT):An Efficient, Recoverable Biphasic Catalyst For Esterification of Carboxylic Acids with Equimolar Amounts of Alcohols

Esterification of carboxylic acid with equimolar amounts alcohol can be efficiently catalyzed by biphasic 4-(benzylamino)formoyldiphenylammonium triflate (BDPAT, 3) in good yield. The catalyst can be easily recovered without loss of activity.

《孙子兵法》对高校教师的启示

高校教师是教学管理工作的主要承担者,教师的素质高低会直接影响高校的生存与发展。通过提炼《孙子兵法》中的将帅思想,分别从“将有五德”“进不求名,退不避罪,唯人是保,利合于主”“求之于势,不责于人”和“令之于文,齐之于武”4个方面提出了促进高校教师成长和发展的策略思考。

Close-in weapon system planning based on multi-living agent theory

The close-in weapon system(CIWS)is a combat system that faces a complex environment full of dynamic and unknown challenges,whose construction and planning require a systematic design method.Multiliving agent(MLA)theory is a methodology for the combat system design,which uses the livelihood degree to evaluate the multi-dimensional long-term operational effectiveness of the system;whereas,there is still no uniform quantization framework for the livelihood degree,and the adjustment methods of livelihood degree need to be further improved.In this paper,we propose the uniform quantization framework for the livelihood degree and detailed discuss the methods of livelihood adjustment.Based on the MLA theory,the multi-dimensional operational effectiveness of the missile-gun integrated weapon system(MGIWS)is analyzed,and the long-term combat effectiveness against the saturation attack is assessed.Furthermore,the planning problem of the equipment deployment and configuration is investigated.Two objectives,including the overall livelihood degree and cost-effectiveness(CE),are proposed,and the optimization method based on genetic algorithm(GA)is studied for the planning problem.

Complement factor B knockdown by short hairpin RNA inhibits laser-induced choroidal neovascularization in rats

AIM:To evaluate whether recombinant complement factor B(CFB)short hairpin RNA(sh RNA)reduces laserinduced choroidal neovascularization(CNV)in rats.METHODS:Laser-induced rat CNV model was established,and then the animals underwent fundus fluorescence angiography(FFA)and hematoxylin and eosin(HE)staining.On day 3 and 7 after photocoagulation,the expression of CFB and membrane attack complex(MAC)was detected by immunhischemistry.A recombinant CFBsh RNA plasmid was constructed.CFB and scrambled sh RNA plasmids were intravenous injected into rats via the tail vein on the day of laser treatment,respectively.On day 7,the incidence of CNV was determined by FFA,and the expression of CFB and vascular endothelial growth factor(VEGF)in retinal pigment epithelium(RPE)/choroidal tissues was detected by immunhischemistry,Western blot and/or semi-quantitative reverse transcription-polymerase chain reaction(RT-PCR)in CFB and scrambled sh RNA groups.The possible adverse effects of CFB-sh RNA injection were assessed by transmission electron microscopy and electroretinography.RESULTS:FFA and HE results indicated that a laserinduced rat CNV model was successfully established on day 7 after photocoagulation.The expression of CFB and MAC was extremely weak in normal retina and choroid,and increased on day 3 after photocoagulation.However,it started to reduce on day 7.CFB sh RNA plasmid was successfully constructed and induced CFB knockdown in the retinal and choroidal tissues.FFA showed CFB knockdown significantly inhibited incidence of CNV in rats.Moreover,CFB knockdown significantly inhibited the expression of VEGF in RPE/choroidal tissues.CFB sh RNA caused no obvious side effects in eyes.CONCLUSION:CFB knockdown significantly inhibits the formation and development of CNV in vivo through reducing the expression of VEGF,which is a potential therapy target.The alternative pathway of complement activation plays an important role in CNV formation.

ATG5介导肝癌细胞对抗营养危机的作用研究

目的探索在小鼠肿瘤细胞中对抗营养缺乏的分子途径。方法构建ATG5基因表达的质粒并瞬时转染至细胞内;用不同靶基因的si-RNAs转染到细胞来沉默基因的表达;不同条件下提取小鼠正常肝细胞AML-12和肝癌细胞Hepa1-6的RNA和蛋白;用q RT-PCR检测基因的表达;用Western blot检测蛋白的表达;用流式细胞仪检测细胞周期;用CCK-8的试剂测定细胞活性。结果与小鼠正常肝细胞AML-12比较,肝癌细胞Hepa1-6对缺血引发的细胞死亡有抵抗性。缺血使Hepa1-6细胞内诱导自噬相关蛋白ATG5表达升高(P<0.05);沉默内源ATG5基因后Hepa1-6细胞对缺血的敏感性升高,且ATG5诱导细胞周期抑制蛋白p21(cip1/waf1)表达增加使细胞滞留在G_1期。结论在营养缺乏的环境中,Hepa1-6细胞内ATG5表达升高,且ATG5增加p21(cip1/waf1)的表达量使细胞滞留在G_1期,可能与对抗缺血引起的死亡有关。

Amelioration of ligamentum flavum hypertrophy using umbilical cord mesenchymal stromal cell-derived extracellular vesicles

Ligamentum flavum(LF)hypertrophy(LFH)has been recognised as one of the key contributors to lumbar spinal stenosis.Currently,no effective methods are available to ameliorate this hypertrophy.In this study,human umbilical cord mesenchymal stromal cell-derived extracellular vesicles(hUCMSC-EVs)were introduced for the first time as promising vehicles for drug delivery to treat LFH.The downregulation of miR-146a-5p and miR-221-3p expressions in human LF tissues negatively correlated with increased LF thickness.The hUCMSC-EVs enriched with these two miRNAs significantly suppressed LFH in vivo and notably ameliorated the progression of transforming growth factorβ1(TGF-β1)-induced fibrosis in vitro after delivering these two miRNAs to mouse LF cells.The results further demonstrated that miR-146a-5p and miR-221-3p directly bonded to the 3′-UTR regions of SMAD4 mRNA,thereby inhibiting the TGF-β/SMAD4 signalling pathway.Therefore,this translational study determined the effectiveness of a hUCMSC-EVs-based approach for the treatment of LFH and revealed the critical target of miR-146a-5p and miR-221-3p.Our findings provide new insights into promising therapeutics using a hUCMSC-EVs-based delivery system for patients with lumbar spinal stenosis.

Solid-Phase Total Synthesis of 1-β-Methylcarbapenem

A 1-b-methylcarbapenem analogue 6 was synthesized on polystyrene-diethylsilane resin (PS-DES) using 2-azetidinone bearing with 2-oxazolidone chiral auxiliary as starting material.

Soluble Polymer-supported Synthesis of Indoles via Palladium-mediat-ed Heteroannulation of Terminal Alkynes with o-Iodoanilines

A soluble polymer-supported synthesis of indoles via palladium-mediated hetero- annulation of terminal alkynes with o-iodoanilines has been described. The protocol provides a useful tool for constructing combinatorial indole libraries.

Improved Superconducting Qubit State Readout by Path Interference

High fidelity single shot qubit state readout is essential for many quantum information processing protocols. In superconducting quantum circuit, the qubit state is usually determined by detecting the dispersive frequency shift of a microwave cavity from either transmission or reflection. We demonstrate the use of constructive interference between the transmitted and reflected signal to optimize the qubit state readout, with which we find a better resolved state discrimination and an improved qubit readout fidelity. As a simple and convenient approach, our scheme can be combined with other qubit readout methods based on the discrimination of cavity photon states to further improve the qubit state readout.

Combination of AAV-delivered tumor suppressor PTEN with anti-PD-1 loaded depot gel for enhanced antitumor immunity

Recent clinical studies have shown that mutation of phosphatase and tensin homolog deleted on chromosome 10(PTEN)gene in cancer cells may be associated with immunosuppressive tumor microenvironment(TME)and poor response to immune checkpoint blockade(ICB)therapy.Therefore,efficiently restoring PTEN gene expression in cancer cells is critical to improving the responding rate to ICB therapy.Here,we screened an adeno-associated virus(AAV)capsid for efficient PTEN gene delivery into B16F10 tumor cells.We demonstrated that intratumorally injected AAV6-PTEN successfully restored the tumor cell PTEN gene expression and effectively inhibited tumor progression by inducing tumor cell immunogenic cell death(ICD)and increasing immune cell infiltration.Moreover,we developed an anti-PD-1 loaded phospholipid-based phase separation gel(PPSG),which formed an in situ depot and sustainably release anti-PD-1 drugs within 42 days in vivo.In order to effectively inhibit the recurrence of melanoma,we further applied a triple therapy based on AAV6-PTEN,PPSG^(@anti-PD-1)and CpG,and showed that this triple therapy strategy enhanced the synergistic antitumor immune effect and also induced robust immune memory,which completely rejected tumor recurrence.We anticipate that this triple therapy could be used as a new tumor combination therapy with stronger immune activation capacity and tumor inhibition efficacy.

Electron delocalization-enhanced sulfur reduction kinetics on an MXene-derived heterostructured electrocatalyst

Lithium-sulfur(Li-S)batteries mainly rely on the reversible electrochemical reaction of between lithium ions(Li^(+))and sulfur species to achieve energy storage and conversion,therefore,increasing the number of free Li^(+)and improving the Li^(+)diffusion kinetics will effectively enhance the cell performance.Here,Mo-based MXene heterostructure(MoS_(2)@Mo_(2)C)was developed by partial vulcanization of Mo_(2)C MXene,in which the introduction of similar valence S into Mo-based MXene(Mo_(2)C)can create an electron delocalization effect.Through theoretical simulations and electrochemical characterisation,it is demonstrated that the MoS_(2)@Mo_(2)C heterojunction can effectively promote ion desolvation,increase the amount of free Li^(+),and accelerate Li^(+)transport for more efficient polysulfide conversion.In addition,the MoS_(2)@Mo_(2)C material is also capable of accelerating the oxidation and reduction of polysulfides through its sufficient defects and vacancies to further enhance the catalytic efficiency.Consequently,the Li-S battery with the designed MoS_(2)@Mo_(2)C electrocatalyst performed for 500 cycles at 1 C and still maintained the ideal capacity(664.7 mAh·g^(−1)),and excellent rate performance(567.6 mAh·g^(−1)at 5 C).Under the extreme conditions of high loading,the cell maintained an excellent capacity of 775.6 mAh·g^(−1)after 100 cycles.It also retained 838.4 mAh·g^(−1)for 70 cycles at a low temperature of 0℃,and demonstrated a low decay rate(0.063%).These results indicate that the delocalized electrons effectively accelerate the catalytic conversion of lithium polysulfide,which is more practical for enhancing the behaviour of Li-S batteries.

Evolutionary trajectory of TRPM2 channel activation by adenosine diphosphate ribose and calcium

Ion channel activation upon ligand gating triggers a myriad of biological events and,therefore,evolution of ligand gating mechanism is of fundamental importance.TRPM2,a typical ancient ion channel,is activated by adenosine diphosphate ribose(ADPR)and calcium and its activation has evolved from a simple mode in invertebrates to a more complex one in vertebrates,but the evolutionary process is still unknown.Molecular evolutionary analysis of TRPM2s from more than 280 different animal species has revealed that,the C-terminal NUDT9-H domain has evolved from an enzyme to a ligand binding site for activation,while the N-terminal MHR domain maintains a conserved ligand binding site.Calcium gating pattern has also evolved,from one Ca^(2+)-binding site as in sea anemones to three sites as in human.Importantly,we identified a new group represented by olTRPM2,which has a novel gating mode and fills the missing link of the channel gating evolution.We conclude that the TRPM2 ligand binding or activation mode evolved through at least three identifiable stages in the past billion years from simple to complicated and coordinated.Such findings benefit the evolutionary investigations of other channels and proteins.