温度和轴压对花岗岩动态力学性能的影响（英文）

为了得到高温高应力下岩石的动态力学性能，对其进行冲击加载实验。对SHPB实验系统进行改进，使该系统能够实现温度与轴压共同作用下的冲击加载实验。采用扫描电子显微镜观察花岗岩碎片的内部结构特征。研究结果表明：花岗岩的纵波波速随温度的升高呈下降趋势，先快速后缓慢下降；花岗岩的单轴动态抗压强度随温度的升高呈下降趋势，其值在25~100°C比在100~300°C时下降得更加明显；峰值应变则随温度的升高而逐渐增大，同样以100°C为分界点，先快速后缓慢增加；随着温度的增加，花岗岩内部发生了巨大的变化，如原生裂纹和新生裂纹的扩展和贯通。另外，轴压下的热损伤比以波速表征的热损伤大，特别是随着温度的增加，这种现象更加明显。

热处理砂岩在干燥和饱水条件下的动态拉伸强度与破坏机理

为了研究不同加载速率下具有水热耦合损伤岩石的拉伸强度和破坏机理,在干燥和饱水条件下,对热处理砂岩进行一系列静态和动态劈裂试验。实验结果表明,高温有效地削弱砂岩试件的抗拉强度,P波速度随温度的升高而降低。总体而言,岩石热损伤随温度的升高而逐渐增大,但在100°C时出现明显的负损伤。饱水砂岩试样的间接抗拉强度低于干燥砂岩的,说明水-岩相互作用导致热处理岩石产生二次损伤。砂岩在干燥和饱水条件下的动态拉伸强度均随应变率的增大而增大。饱水砂岩比干燥砂岩表现出较强的加载率依赖性,但岩石的加载速率敏感性随热处理温度的升高而降低。利用扫描电子显微镜技术,对极端温度引起的岩石热破裂进行分析,进一步探讨热处理后砂岩在不同加载速率条件下的水物理机制。

中等加载速率下微波损伤砂岩的动态抗压强度及破坏机理

为了研究微波加热对岩石动态特性和破坏机制的影响,使用改进的分离式霍普金森压杆系统对微波辐射砂岩试样进行动态压缩试验。结果表明,微波辐射能有效降低砂岩的抗压强度。冲击荷载作用下试样呈现出3种不同的破坏模式:拉伸破坏、拉伸−剪切复合破坏和压缩−剪切破坏。利用实测的纵、横波速度计算得到的动态泊松比来描述砂岩的变形特征。随着微波功率和加热时间的增加,泊松比先下降后略有增加,转折点温度出现在244.6℃。此外,微观结构特征表明,微波辐射对岩石产生脱水、扩孔和致裂效应。基于岩石内部热应力和蒸汽压力,探讨微波辐射对岩石的损伤机理,为实验结果提供合理的解释。

HIF-1α induces VE-cadherin expression and modulates vasculogenic mimicry in esophageal carcinoma cells

AIM:To investigate whether hypoxia inducible factor(HIF)-1αmodulates vasculogenic mimicry(VM)by upregulating VE-cadherin expression in esophageal squamous cell carcinoma(ESCC).METHODS:Esophageal squamous cancer cell lines Eca109 and TE13 were transfected with plasmids harboring small interfering RNAs targeting HIF-1αor VEcadherin.The proliferation and invasion of esophageal carcinoma cells were detected by MTT and Transwell migration assays.The formation of tubular networks of cells was analyzed by 3D culture in vitro.BALB/c nude mice were used to observe xenograft tumor formation.The relationship between the expression of HIF-1αand VE-cadherin,ephrin A2(Eph A2)and laminin5γ2(LN5γ2)was measured by Western blot and real-time polymerase chain reaction.RESULTS:Knockdown of HIF-1αinhibited cell proliferation(32.3%±6.1%for Eca109 cells and 38.6%±6.8%for TE13 cells,P<0.05).Both Eca109 and TE13cells formed typical tubular networks.The number of tubular networks markedly decreased when HIF-1αor VE-cadherin was knocked down.Expression of VEcadherin,Eph A2 and LN5γ2 was dramatically inhibited,but the expression of matrix metalloproteinase 2 had no obvious change in HIF-1α-silenced cells.Knockdown of VE-cadherin significantly decreased expression of both Eph A2 and LN5γ2(P<0.05),while HIF-1αexpression was unchanged.The time for xenograft tumor formation was 6±1.2 d for Eca109 cells and Eca109cells transfected with HIF-1αNeo control short hairpin RNA(sh RNA)vector,and 8.4±2.1 d for Eca109 cells transfected with an sh RNA against HIF-1α.Knockdown of HIF-1αinhibited vasculogenic mimicry(VM)and tumorigenicity in vivo.CONCLUSION:HIF-1αmay modulate VM in ESCC by regulating VE-cadherin expression,which affects VM formation through Eph A2 and LN5γ2.

Exogenous nerve growth factor protects the hypoglossal nerve against crush injury

Studies have shown that sensory nerve damage can activate the p38 mitogen-activated protein kinase（MAPK）pathway,but whether the same type of nerve injury after exercise activates the p38MAPK pathway remains unclear.Several studies have demonstrated that nerve growth factor may play a role in the repair process after peripheral nerve injury,but there has been little research focusing on the hypoglossal nerve injury and repair.In this study,we designed and established rat models of hypoglossal nerve crush injury and gave intraperitoneal injections of exogenous nerve growth factor to rats for 14 days.p38MAPK activity in the damaged neurons was increased following hypoglossal nerve crush injury;exogenous nerve growth factor inhibited this increase in acitivity and increased the survival rate of motor neurons within the hypoglossal nucleus.Under transmission electron microscopy,we found that the injection of nerve growth factor contributed to the restoration of the morphology of hypoglossal nerve after crush injury.Our experimental findings indicate that exogenous nerve growth factor can protect damaged neurons and promote hypoglossal nerve regeneration following hypoglossal nerve crush injury.

Thiourea-assisted coating of dispersed copper electrocatalysts on Si photocathodes for solar hydrogen production

Photoelectrochemical water splitting can convert solar energy into clean hydrogen energy for storage.It is desirable to explore non-precious electrocatalysts for practical applications of a photoelectrode in a large scale.Here,we developed a facile spin-coating and in-situ photoelectrochemical reduction method to prepare a dispersed Cu electrocatalyst on a Si photocathode,which improves the performance remarkably.We find that thiourea in the precursor solution for spin-coating plays an important role in obtaining dispersed Cu particles on the surface of a Si photoelectrode.With thiourea in the precursor,the Cu/Si photocathode shows higher performance than the one without thiourea.Moreover,the Cu/Si photocathode also indicates good stability after 16 h illumination.

Endothelial METRNL determines circulating METRNL level and maintains endothelial function against atherosclerosis

METRNL is a recently identified secreted protein with emerging functions.This study is to find major cellular source of circulating METRNL and to determine METRNL novel function.Here,we show METRNL is abundant in human and mouse vascular endothelium and released by endothelial cells using endoplasmic reticulum-Golgi apparatus pathway.By creating endothelial cell-specific Metrnl knockout mice,combined with bone marrow transplantation to produce bone marrow-specific deletion of Metrnl,we demonstrate that most of circulating METRNL(approximately 75%)originates from the endothelial cells.Both endothelial and circulating METRNL decrease in atherosclerosis mice and patients.By generating endothelial cell-specific Metrnl knockout in apolipoprotein E-deficient mice,combined with bone marrow-specific deletion of Metrnl in apolipoprotein E-deficient mice,we further demonstrate that endothelial METRNL deficiency accelerates atherosclerosis.Mechanically,endothelial METRNL deficiency causes vascular endothelial dysfunction including vasodilation impairment via reducing eNOS phosphorylation at Ser1177 and inflammation activation via enhancing NFκB pathway,which promotes the susceptibility of atherosclerosis.Exogenous METRNL rescues METRNL deficiency induced endothelial dysfunction.These findings reveal that METRNL is a new endothelial substance not only determining the circulating METRNL level but also regulating endothelial function for vascular health and disease.METRNL is a therapeutic target against endothelial dysfunction and atherosclerosis.

Astragaloside IV derivative HHQ16 ameliorates infarctioninduced hypertrophy and heart failure through degradation of lncRNA4012/9456

Reversing ventricular remodeling represents a promising treatment for the post-myocardial infarction(MI)heart failure(HF).Here,we report a novel small molecule HHQ16,an optimized derivative of astragaloside IV,which effectively reversed infarction-induced myocardial remodeling and improved cardiac function by directly acting on the cardiomyocyte to reverse hypertrophy.The effect of HHQ16 was associated with a strong inhibition of a newly discovered Egr2-affliated transcript Inc9456 in the heart.While minimally expressed in normal mouse heart,Inc9456 was dramatically upregulated in the heart subjected to left anterior descending coronary artery ligation(LADL)and in cardiomyocytes subjected to hypertrophic stimulation.The critical role of Inc9456 in cardiomyocyte hypertrophy was confirmed by specific overexpression and knockout in vitro.A physical interaction between Inc9456 and G3BP2 increased NF-kB nuclear translocation,triggering hypertrophy-related cascades.HHQ16 physically bound to Inc9456 with a high-affinity and induced its degradation.Cardiomyocyte-specific Inc9456 overexpression induced,but knockout prevented LADL-induced,cardiac hypertrophy and dysfunction.HHQ16 reversed the effect of Inc9456 overexpression while lost its protective role when Inc9456 was deleted,further confirming Inc9456 as the bona fide target of HHQ16.We further identified the human ortholog of Inc9456,also an Egr2-affliated transcript,Inc4012.Similarly,Inc4012 was significantly upregulated in hypertrophied failing hearts of patients with dilated cardiomyopathy.HHQ16 also specifically bound to Inc4012 and caused its degradation and antagonized its hypertrophic effects.Targeted degradation of pathological increased Inc4012/lnc9456 by small molecules might serve as a novel promising strategy to regress infarction-induced cardiac hypertrophy and HF.

艾灸对血管性痴呆大鼠神经干细胞移植后海马NR2B和PKMζ的影响

Objective:To observe the influence of moxibustion on learning and memory ability in the rats with vascular dementia(VD) and explore the potential effect mechanism.Methods:A total of 80 rats,screened by Morris water maze,were randomly divided into a shamoperation group,a model group,a neural stem cells(NSCs) group,a NSCs+piracetam group and a NSCs+moxibustion group,16 rats in each group.After corresponding treatments,Morris water maze and immunofluorescence technique were adopted to evaluate the therapeutic effect respectively.Results:Comparison among groups after modeling:compared with the sham-operation group,the escape latency was longer(P<0.01) and the times of crossing platform were reduced(P<0.01) in the rats of the model group.Comparison among groups after treatment:compared with the model group,the escape latency was shortened(P<0.01) and the times of crossing platform were increased(P<0.05) in the rats of the NSCs group.Compared with the NSCs group,the escape latency was shorter and the expressions of the hippocampus NR2B/EGFP and PKM ξ/EGFP expression level increased(all P<0.05) in the rats of the NSCs+piracetam group and the NSCs+moxibustion group(all P <0.05).Compared with the NSCs+piracetam group,the escape latency was shorter and the expressions of the hippocampus NR2B/EGFP and PKM ξ/EGFP expression level were higher in the rats of the moxibustion+NSCs group(all P<0.05).Conclusion:Moxibustion improves the spatial learning and memory ability of the VD rats and promotes the reconstruction of neurogenesis and synaptic function,which may be related to the up-regulation of the expressions of hippocampus NR2B and PKMξ expressions.

Efficient purification of Al_(30) by organic complexation method

A method was developed for preparing high purity Al30O8(OH)56(H2O)_(24)^(18)+(Al30) through elimination of impurities by complexation.Polyaluminum chloride II(PAC_(30))with Al_(c )content of 75%was adopted as the source of Al_(30).The PAC_(30)was prepared under conditions of total aluminum concentration 0.1 mol/L and OH^-/Al ratio 2.2 to obtain the highest content of Al_(30).A precipitation/metathesis method,organic solvent precipitation method and organic complexation method were examined to separate and purify Al_(30).It was found that only by the organic complexation method could high purity Al_(30)products be obtained in large yield economically.In the experiments,benzoic acid was used as the coordinating reagent to decompose the main impurity AlO_4Al_(12)(OH)_(24)(H_2O)_(12)^(7+)(Al_(13)),and the Al_(30)product could be obtained by precipitation and metathesis operations.It was noteworthy that the decomposition of impurities by benzoic acid could be completed in 2 hr.The Al_(30)product was characterized by Ferron assay,^(27)Al-NMR,SEM,XRD and TGA.The results showed that the purity of the Al_(30)product could exceed 92%.

A novel clustered SPIO nanoplatform with enhanced magnetic resonance T2 relaxation rate for micro-tumor detection and photothermal synergistic therapy

Construction of micro tumor sensitive theranostic nanoagents that can increase the accuracy of imaging diagnosis and boost the therapeutic efficacy has been demonstrated for a promising approach for diagnosis and treatment of cancer.Herein,we reported a novel super-paramagnetic iron oxide(SPIO)based nanoplatform that possess significantly enhanced magnetic resonance property and photothermal effect for tumor theranostic purpose.This polyethylene glycol with four phenylboronic acid(PEG-B4)/CNTs@porphyrin(ph)/SPIO(BCPS)nanoplatform was simply prepared via integrated SPIO,ph,and a novel dendrimer with PEG liner and four PBA groups(PEG-B4)on the surface of carbon nanotubes(CNTs).Subsequently,a significant T2 relaxation rate enhanced can be achieved by the reduced accessibility of water to SPIO clustering.Moreover,the synergetic enhanced photothermal from BCPS nanoplatform contributed to better photothermal effect for cancer therapy.Furthermore,the targeting ability to sialic acid overexpressed tumor was further introduced from phenylboronic acid from PEG-B4.We showed that BCPS nanoplatform could not only selectively identify solid tumors and detect micro-sized metastatic tumor(1 mm)in the liver,but also effectively ablate tumors in a xenograft model,thereby achieving a complete cure rate of 100%at low laser dose.Our results highlight the potential of BCPS nanoplatform for accurate micro-tumor diagnosis and effective tumor therapy.

An Extrinsic Faradaic Layer on CuSn for High-Performance Electrocatalytic CO_(2) Reduction

An intrinsic Faradaic layer on the surface of a metal electrocatalyst is usually considered an active site for CO_(2) reduction.Different strategies have been used to improve the performance of CO_(2) reduction by adjusting the intrinsic Faradaic layer.However,it is still challenging to achieve CO_(2) reduction with high activity,selectivity,and stability.In this study,for the first time,we improve the three parameters simultaneously by introducing a Zn(OH)_(x) over layer onto a CuSn electrocatalyst.We find that the intrinsic Faradaic layer of Sn(OH)_(x) on the surface of CuSn provides active sites for CO_(2) reduction,while Zn(OH)_(x) plays multiple roles as an adsorption/activation layer,a cover layer,and a protective layer.Further studies suggest that the enhanced activity comes from a Faradaic reaction of Zn(OH)_(x) during CO_(2) reduction,which can be considered as an extrinsic Faradaic layer.This new strategy of introducing an extrinsic Faradaic layer can deepen understanding of electrocatalytic process and offers guidance to design other high-performance electrocatalysts.

Corrigendum to<’Efficient purification of Al_(30) by organic complexation method’><[Journal of Environmental Sciences 80(2019)240-247]>30

The authors regret<the information of authors and affiliations“Libing Liu Qinxue Yang 2,3,Pin Wang 1,2,Feng Xiao 2,Ruyuan Jiao 2,Guangyu An 2,∗,Dongsheng Wang 2,∗1,2,1.University of Chinese Academy of Sciences,Beijing 100085,China 2.State Key Laboratory of Environmental Aquatic Chemistry,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing 100085,China3.Faculty Materials Science and Chemistry,China University of Geosciences,Wuhan 430074,China”should be changed to“Libing Liu 1,2,Qinxue Yang 1,3,Pin Wang 1,2,Feng Xiao 1,Ruyuan Jiao 1,Guangyu An 1,∗,Dongsheng Wang 1,∗1.State Key Laboratory of Environmental Aquatic Chemistry,Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing 100085,China 2.University of Chinese Academy of Sciences,Beijing 100049,China 3.Faculty Materials Science and Chemistry,China University of Geosciences,Wuhan 430074,China”>.

A new evaluation model of comprehensive radio frequency stealth performance of radar

The detection capabilities of passive electronic warfare reconnaissance equipment have substantially increased during recent years.Correspondingly,the radar equipment is required to take various means to improve the radio frequency(RF)stealth performance to ensure the transmitted RF signal does not get intercepted.However,traditional evaluation methods on RF stealth performance cannot accurately evaluate the RF stealth capabilities of new system radar.In this study,a joint interception probability evaluation model on RF stealth performance was established,which divided the interception process into two parts:front interception and system interception.Various RF stealth means adopted by different radar equipment were taken into consideration to improve the applicability of this model.Simulation results show that this model is able to effectively characterize almost all the aspects of the RF stealth features and can serve as a good reference to evaluate RF radar stealth performance comprehensively.

A novel method for objectively, rapidly and accurately evaluating burn depth via near infrared spectroscopy

The accurate and objective evaluation of burn depth is a significant challenge in burn wound care.Herein,we used near infrared spectroscopy(NIRS)technology to measure the different depth of thermal burns in ex vivo porcine models.Based on the intensity of the spectral signals and the diffuse reflection theory,we extracted the optical parameters involved in functional(total hemoglobin andwater content)and structural(tissue scattered size and scattered particles)features that reflect the changes in burn depth.Next,we applied support vector regression to construct a model including the optical property parameters and the burn depth.Finally,we histologically verified the burn depth data collected via NIRS.The results showed that our inversion model could achieve an average relative error of about 7.63%,while the NIRS technology diagnostic accuracy was in the range of 50μm.For the first time,this novel technique provides physicians with real-time burn depth information objectively and accurately.

Therapeutic strategies for targeting cancer stem cells

The therapeutic limitations of conventional chemotherapeutic drugs present a challenge for cancer therapy;these shortcomings are largely attributed to the ability of cancer cells to repopulate and metastasize after initial therapies.Compelling evidence suggests that cancer stem cells(CSCs)have a crucial impact in current shortcomings of cancer therapy because they are largely responsible for tumor initiation,relapse,metastasis,and chemo-resistance.Thus,a better understanding of the properties and mechanisms underlying CSC resistance to treatments is necessary to improve patient outcomes and survival rates.In this review,the authors characterize and compare different CSC-specific biomarkers that are present in various types of tumors.We further discuss multiple targeting approaches currently in preclinical or clinical testing that show great potential for targeting CSCs.This review discusses numerous strategies to eliminate CSCs by targeting surface biomarkers,regulating CSC-associated oncogenes and signaling pathways,inhibiting drug-efflux pumps involved in drug resistance,modulating the tumor microenvironment and immune system,and applying drug combination therapy using nanomedicine.