Composite coatings consisting of carbon and polytetrafluoroethylene(PTFE) were prepared on Ti alloy substrate by a simple two-step process of hydrothermal and impregnation. The morphology, composition, hydrophobic and...Composite coatings consisting of carbon and polytetrafluoroethylene(PTFE) were prepared on Ti alloy substrate by a simple two-step process of hydrothermal and impregnation. The morphology, composition, hydrophobic and corrosion properties of the composite coatings were characterized by scanning electron microscopy(SEM), Fourier transform infrared spectroscopy(FTIR), water contact angle method, X-ray photoelectron spectroscopy(XPS) and electrochemical technique, respectively. The effect of PTFE content on the corrosion properties of the composite coatings was studied. It is found that the composite coating film exhibits a full coverage with uniformly distributed PTFE when 0.1 mol/L of glucose is used as carbon source and 20 wt.% PTFE suspension as impregnating solution. The coating with 20 wt.% PTFE has a good bonding strength with Ti plate and exhibits excellent hydrophobic property with a water contact angle of 142.3° as well as superior corrosion resistance with corrosion current density as low as 0.0045 μA/cm^2. With regard to its excellent hydrophobicity and corrosion resistance, the carbon-PTFE composite coating may find potential application in automobiles and metal corrosion industries.展开更多
Objective Pituitary adenomas(PAs)can adapt an aggressive phenotype by invading adjacent brain structures with rapid cellular proliferation.Previous studies demonstrated that excessive expression of metalloproteases AD...Objective Pituitary adenomas(PAs)can adapt an aggressive phenotype by invading adjacent brain structures with rapid cellular proliferation.Previous studies demonstrated that excessive expression of metalloproteases ADAM12 and MMP-14 is instrumental for the active proliferation and invasiveness of PA cells in vitro and of tumors in vivo.However,the mechanisms regulating ADAM12 and MMP-14 expression in PAs remain unclear.Methods Target gene prediction and transcriptomic profiling of invasive vs.noninvasive human PA samples were performed to identify miRNA species potentially involved in the regulation of ADAM12 and MMP14.For cellular analyses of miRNA functions,two mouse PA cell lines(AtT20 and TtT/GF)were transfected with miR-149-3p and miR-149-5p,respectively.The effects of miR-149(3p and 5p)on expression levels of ADAM12 and MMP14 were determined by Western blotting followed by an analysis of proliferation and colony formation assays,scratch migration assays,and invasion assays.Results A significant downregulation of miRNA-149 was observed in invasive vs.noninvasive PA(0.32 vs.0.09,P<0.0001).In AtT-20 and TtT/GF mouse PAs cells,transfection of mimic miRNA-149(3p and 5p)caused a significantly reduced cell proliferation and matrigel invasion,whilst the effect on cell migration was less pronounced.Both strands of miRNA-149(3p and 5p)markedly reduced protein levels of ADAM12 and MMP-14 by at least 40%in both cell lines.Conclusion This study proved that the invasiveness of PA cells is,at least partly,regulated by miRNA-149-dependent expression of ADAM12 and MMP-14.展开更多
Objective Pituitary adrenocorticotropic hormone(ACTH)-secreting adenoma is a relatively intractable endocrine adenoma that can cause a range of severe metabolic disorders and pathological changes involving multiple sy...Objective Pituitary adrenocorticotropic hormone(ACTH)-secreting adenoma is a relatively intractable endocrine adenoma that can cause a range of severe metabolic disorders and pathological changes involving multiple systems.Previous studies have shown that celastrol has antitumor effects on a variety of tumor cells via the AKT/mTOR signaling.However,whether celastrol has pronounced antitumor effects on pituitary ACTH-secreting adenoma is unclear.This study aimed to identify a new effective therapeutic drug for pituitary ACTH-secreting adenoma.Methods Mouse pituitary ACTH-secreting adenoma cells(AtT20 cells)were used as an experimental model in vitro and to establish a xenograft tumor model in mice.Cells and animals were administered doses of celastrol at various levels.The effects of celastrol on cell viability,migration,apoptosis and autophagy were then examined.Finally,the potential involvement of AKT/mTOR signaling in celastrol’s mechanism was assessed.Results Celastrol inhibited the proliferation and migration of pituitary adenoma cells in a time-and concentration-dependent manner.It blocked AtT20 cells in the G0/G1 phase,and induced apoptosis and autophagy by downregulating the AKT/mTOR signaling pathway.Similar results were obtained in mice.Conclusion Celastrol exerts potent antitumor effects on ACTH-secreting adenoma by downregulating the AKT/mTOR signaling in vitro and in vivo.展开更多
Graphene, with its zero-bandgap electronic structure, is a highly promising ultra-broadband light absorbing material.However, the performance of graphene-based photodetectors is limited by weak absorption efficiency a...Graphene, with its zero-bandgap electronic structure, is a highly promising ultra-broadband light absorbing material.However, the performance of graphene-based photodetectors is limited by weak absorption efficiency and rapid recombination of photoexcited carriers, leading to poor photodetection performance. Here, inspired by the photogating effect, we demonstrated a highly sensitive photodetector based on graphene/WSe_(2) vertical heterostructure where the WSe_(2) layer acts as both the light absorption layer and the localized grating layer. The graphene conductive channel is induced to produce more carriers by capacitive coupling. Due to the strong light absorption and high external quantum efficiency of multilayer WSe_(2), as well as the high carrier mobility of graphene, a high photocurrent is generated in the vertical heterostructure. As a result, the photodetector exhibits ultra-high responsivity of 3.85×10~4A/W and external quantum efficiency of 1.3 × 10~7%.This finding demonstrates that photogating structures can effectively enhance the sensitivity of graphene-based photodetectors and may have great potential applications in future optoelectronic devices.展开更多
The ratio between vertical and radial amplitudes of Rayleigh waves(hereafter,the Rayleigh wave ZH ratio)is an important parameter used to constrain structures beneath seismic stations.Some previous studies have explor...The ratio between vertical and radial amplitudes of Rayleigh waves(hereafter,the Rayleigh wave ZH ratio)is an important parameter used to constrain structures beneath seismic stations.Some previous studies have explored crust and upper mantle structures by joint inversion of the Rayleigh wave ZH ratio and surface wave dispersion.However,all these studies have used a 1-D depth sensitivity kernel,and this kernel may lack precision when the structure varies a great deal laterally.Here,we present a systematic investigation of the two-dimensional(2-D)Rayleigh wave ZH ratio kernel based on the adjoint-wavefield method and perform two synthetic tests using the new kernel.The 2-D ZH ratio kernel is consistent with the traditional 1-D sensitivity kernel but has an asymmetric pattern with a preferred orientation toward the source.The predominant effect caused by heterogeneity can clearly be seen from kernels calculated from models with 2-D heterogeneities,which confirms the necessity of using the new 2-D kernel in some complex regions.Inversion tests using synthetic data show that the 2-D ZH ratio kernel has the potential to resolve small anomalies as well as complex lateral structures.展开更多
Objective： To investigate the role of tissue factor （TF） in chemotherapeutic reagent - induced apoptosis on human glioblastoma and explore its mechanism. Methods： The expression of TF was examined by Western blott...Objective： To investigate the role of tissue factor （TF） in chemotherapeutic reagent - induced apoptosis on human glioblastoma and explore its mechanism. Methods： The expression of TF was examined by Western blotting. The cytotoxicity of doxorubicin was determined by WST assay. The activation of Caspase-3 and PARP induced by adoxorubicin were tested by Western blotting. Results： Human glioblastoma cell line U373MG expressed high level of TF while LN-229 was with low-TF level. The chemotherapeutic reagent doxorubicin revealed stronger cytotoxic effect on high-TF U373MG cells than IowoTF LN-229 cells. Enforced strong expression of TF was achieved by transfection of TF-pcDNA3 combinant on LN-229 cells in a dose-dependent manner. Enforced TF expression in transfected LN-229 cells not only impaired the doxorubicin-induced cleavage of Caspase-3 and PARP, but also inhibited the cytotoxic effect of doxorubicin. Furthermore, activation of Akt was strong in high-TF U373MG cells but weak in IowoTF LN-229 cells. Incubation of factor VII （FVII） with enforced TF-expressing LN-229 cells increased the phosphorylaUon of Akt in a time-dependent manner. Conclusion： These results suggest that over-expression of TF on glioblastoma could inhibit doxorubicin-induced apoptosis. Interaction of FVII and TF activates the downstream PI3K/Akt pathway. Tumor-derived over-expression of TF might play a role in chemotherapy resistance in glioblastoma, at lest in part, by activating PI3K/Akt-mediated survival and anti-apoptotic mechanism through the interaction of TF/FVII signaling.展开更多
The distribution of titanium,carbon and associated elements(calcium,magnesium,silicon and aluminum)in a smelting process is studied by means of a chemical equilibrium calculation method for multiphase and multicompone...The distribution of titanium,carbon and associated elements(calcium,magnesium,silicon and aluminum)in a smelting process is studied by means of a chemical equilibrium calculation method for multiphase and multicomponent systems,and verified through comparison with production results.In particular,using the coexistence theory for titanium slag structures,the influence of the AIR(anthracite to ilmenite ratio)on the distribution of such elements is analyzed.The results show that the AIR can be adjusted to achieve a selective reduction of oxides in the melt.展开更多
Triplostegia glandulifera Wall(T.glandulifera)is an ethnomedicine commonly used by ethnic minorities in Yunnan,China,to treat kidney disease.However,there are few reports on the renoprotective effects of this substanc...Triplostegia glandulifera Wall(T.glandulifera)is an ethnomedicine commonly used by ethnic minorities in Yunnan,China,to treat kidney disease.However,there are few reports on the renoprotective effects of this substance,and the active ingredients remain unclear.In this study,we extracted the polysaccharide fractions TGB and TGC using the water extraction-alcohol precipitation method and determined their molecular weight(Mw)and monosaccharide composition.The study investigated the protective effects of TGB and TGC fractions against diabetic nephropathy(DN)using an in vitro high glucose-induced HRMCs model and an in vivo STZ-induced diabetic mouse model.HPLC analysis revealed that TGB contained D-galacturonic acid,D-glucose,D-galactose,and D-arabinose,and had a lower Mw than TGC.In vitro,TGB showed concentration-dependent antioxidant activity and effectively reduced abnormal proliferation and while attenuating oxidative stress in HRMCs.In mice with diabetes,TGB corrected the dysregulation of glucose-lipid metabolism and alleviated oxidative stress in the kidneys.Additionally,it improved renal function and reduced renal tissue damage.The study suggests that the low Mw polysaccharides(TGB)have better activity against DN through the antioxidative stress mechanism.展开更多
Volatile organic chemicals(VOC)have been identified as hazardous pollutants impairing human health.While whether the VOC exposure was associated with hyperuricemia is yet clarified.All the data was acquired from 6 sur...Volatile organic chemicals(VOC)have been identified as hazardous pollutants impairing human health.While whether the VOC exposure was associated with hyperuricemia is yet clarified.All the data was acquired from 6 survey cycles of the National Health and Nutrition Examination Survey(NHANES)program(2005–2006,2011–2012,2013–2014,2015–2016,2017–2018,2017–2020).Hyperuricemia was defined as a serum uric acid(SUA)concentration exceeding 7 mg/mL in men or 6 mg/mL in women.Three quantile logistic regression modelswith varied covariateswere developed to analyze the correlation between hyperuricemia and volatile organic chemical metabolites(VOCs)in urine,and three quantile linear regression models were used for examining the correlation between VOCs and SUA.N-acetyl-S-(2-carboxyethyl)-l-cysteine(CEMA),N-acetyl-S-(3,4-dihydroxybutyl)-l-cysteine(DHBM),and phenylglyoxylic acid(PHGA)were identified to associated positively with increased hyperuricemia risk and uric acid level.Meanwhile,the weighted quantile sum(WQS)model suggested a positive association between VOCs exposure and hyperuricemia.These data indicate that VOC exposure potentially increases hyperuricemia risk,necessitating policies to mitigate VOC exposure.展开更多
Background Liver ischemia/reperfusion(I/R)injury is usually caused by hepatic inflow occlusion during liver surgery,and is frequently observed during war wounds and trauma.Hepatocyte ferroptosis plays a critical role ...Background Liver ischemia/reperfusion(I/R)injury is usually caused by hepatic inflow occlusion during liver surgery,and is frequently observed during war wounds and trauma.Hepatocyte ferroptosis plays a critical role in liver I/R injury,however,it remains unclear whether this process is controlled or regulated by members of the DEAD/DExH-box helicase(DDX/DHX)family.Methods The expression of DDX/DHX family members during liver I/R injury was screened using transcriptome analysis.Hepatocyte-specific Dhx58 knockout mice were constructed,and a partial liver I/R operation was performed.Single-cell RNA sequencing(scRNA-seq)in the liver post I/R suggested enhanced ferroptosis by Dhx58hep−/−.The mRNAs and proteins associated with DExH-box helicase 58(DHX58)were screened using RNA immunoprecipitation-sequencing(RIP-seq)and IP-mass spectrometry(IP-MS).Results Excessive production of reactive oxygen species(ROS)decreased the expression of the IFN-stimulated gene Dhx58 in hepatocytes and promoted hepatic ferroptosis,while treatment using IFN-αincreased DHX58 expression and prevented ferroptosis during liver I/R injury.Mechanistically,DHX58 with RNA-binding activity constitutively associates with the mRNA of glutathione peroxidase 4(GPX4),a central ferroptosis suppressor,and recruits the m6A reader YT521-B homology domain containing 2(YTHDC2)to promote the translation of Gpx4 mRNA in an m6A-dependent manner,thus enhancing GPX4 protein levels and preventing hepatic ferroptosis.Conclusions This study provides mechanistic evidence that IFN-αstimulates DHX58 to promote the translation of m6A-modified Gpx4 mRNA,suggesting the potential clinical application of IFN-αin the prevention of hepatic ferroptosis during liver I/R injury.展开更多
With the rapid development of the world economy,complex air pollution has increasingly become a serious threat;for example,with haze events occurring frequently in various regions of the globe.Recent evidence has indi...With the rapid development of the world economy,complex air pollution has increasingly become a serious threat;for example,with haze events occurring frequently in various regions of the globe.Recent evidence has indicated that secondary aerosols play an important role in haze formation,and that heterogeneous processes are among the main forces driving their explosive growth.In this regard,this paper reviews recent advances in the understanding of the impact of heterogeneous processes on haze chemistry,including the impact on NO_(2)chemistry,marine aerosols,and the hygroscopicity and optical properties of atmospheric aerosols.It is distinguished from past reviews on this topic by focusing mainly on new insights from the past five years.We summarize the main findings of the impacts of heterogeneous processes on NO_(2)chemistry,marine aerosols,and the physicochemical properties of atmospheric aerosols,and propose several future research directions.展开更多
共轭高分子材料具有质轻、柔软、成本低、性能易于调控且可溶液加工等特点,在有机电致发光二极管、有机光伏、场效应晶体管与传感器件等领域有广泛的应用前景.共轭高分子体系中的多种弱相互作用使其可以形成复杂的多级组装结构,因此深...共轭高分子材料具有质轻、柔软、成本低、性能易于调控且可溶液加工等特点,在有机电致发光二极管、有机光伏、场效应晶体管与传感器件等领域有广泛的应用前景.共轭高分子体系中的多种弱相互作用使其可以形成复杂的多级组装结构,因此深入研究共轭高分子多级组装对于明确高分子功能材料构效关系具有重要意义.本文立足于系统对比共轭高分子多级组装与蛋白质多级组装的相似性,首次划分了共轭高分子多级组装中存在的四级结构:一级结构为通过共价作用形成的一维聚合物链结构,二级结构为通过分子间相互作用如π-π堆积(π-πstacking)、层状堆叠(lamellar packing)和链缠结等形成的一条或多条聚合物链组装结构,三级结构为不同相行为对应的聚集结构,例如结晶、无定形区域(crystalline and amorphous region)和过渡区域等,四级结构为多组分相互作用及相分离的材料体系.多级结构相互关联,共同决定了共轭高分子材料的光、电、热等物理性质.本文总结了近年来共轭高分子多级组装的相关研究工作,为观察和理解并指导高分子多级组装、建立完整的"构效"关系、优化器件性能提供了新视角.展开更多
Ligustrazine （2,3,5,6-tetramethylpyrazine） is a major active ingredient of the Szechwan lovage rhizome and is extensively used in treatment of ischemic cerebrovascular disease. The mecha- nism of action of ligustraz...Ligustrazine （2,3,5,6-tetramethylpyrazine） is a major active ingredient of the Szechwan lovage rhizome and is extensively used in treatment of ischemic cerebrovascular disease. The mecha- nism of action of ligustrazine use against ischemic cerebrovascular diseases remains unclear at present. This study summarizes its protective effect, the optimum time window of administra- tion, and the most effective mode of administration for clinical treatment of cerebral ischemia/ reperfusion injury. We examine the effects of ligustrazine on suppressing excitatory amino acid release, promoting migration, differentiation and proliferation of endogenous neural stem cells. We also looked at its effects on angiogenesis and how it inhibits thrombosis, the inflammatory response, and apoptosis after cerebral ischemia. We consider that ligustrazine gives noticeable protection from cerebral ischemia/reperfusion injury. The time window of ligustrazine admin- istration is limited. The protective effect and time window of a series of derivative monomers of ligustrazine such as 2-[（1,1-dimethylethyl）oxidoimino]methyl]-3,5,6-trimethylpyrazine, CXC137 and CXC 195 after cerebral ischemia were better than ligustrazine.展开更多
The latest edition of the WHO classification of the central nervous system was published in 2021.This review summarizes the major revisions to the classification of anterior pituitary tumors.The most important revisio...The latest edition of the WHO classification of the central nervous system was published in 2021.This review summarizes the major revisions to the classification of anterior pituitary tumors.The most important revision involves preferring the terminology of pituitary neuroendocrine tumor(PitNET),even though the terminology of pituitary adenoma(PA)still can be used according to this WHO classification compared to the previous one.Moreover,immunohistochemistry(IHC)examination of pituitary-specific transcription factors(TFs),including PIT1,TPIT,SF-1,GATA2/3,and ERα,is endorsed to determine the tumor cell lineage and to facilitate the classification of PitNET/PA subgroups.However,TF-negative IHC staining indicates PitNET/PA with no distinct cell lineages,which includes unclassified plurihormonal(PH)tumors and null cell(NC)tumors in this edition.The new WHO classification of PitNET/PA has incorporated tremendous advances in the understanding of the cytogenesis and pathogenesis of pituitary tumors.However,due to the shortcomings of the technology used in the diagnosis of PitNET/PA and the limited understanding of the tumorigenesis of PitNET/PA,the application of this new classification system in practice should be further evaluated and validated.Besides providing information for deciding the follow-up plans and adjunctive treatment after surgery,this classification system offers no additional help for neurosurgeons in clinical practice,especially in determining the treatment strategies.Therefore,it is necessary for neurosurgeons to establish a comprehensive pituitary classification system for PitNET/PA that incorporates neuroimaging grading data or direct observation of invasiveness during operation or the predictor of prognosis,as well as pathological diagnosis,thereby distinguishing the invasiveness of the tumor and facilitating neurosurgeons to decide on the treatment strategies and follow-up plans as well as adjunctive treatment after surgery.展开更多
Robot hands have been developing during the last few decades. There are many mechanical structures and analyti?cal methods for di erent hands. But many tough problems still limit robot hands to apply in homelike envir...Robot hands have been developing during the last few decades. There are many mechanical structures and analyti?cal methods for di erent hands. But many tough problems still limit robot hands to apply in homelike environment. The ability of grasping objects covering a large range of sizes and various shapes is fundamental for a home service robot to serve people better. In this paper, a new grasping mode based on a novel sucked?type underactuated(STU) hand is proposed. By combining the flexibility of soft material and the e ect of suction cups, the STU hand can grasp objects with a wide range of sizes, shapes and materials. Moreover, the new grasping mode is suitable for some situations where the force closure is failure. In this paper, we deduce the e ective range of sizes of objects which our hand using the new grasping mode can grasp. Thanks to the new grasping mode, the ratio of grasping size between the biggest object and the smallest is beyond 40, which makes it possible for our robot hand to grasp diverse objects in our daily life. For example, the STU hand can grasp a soccer(220 mm diameter, 420 g) and a fountain pen(9 mm diameter, 9 g). What’s more, we use the rigid body equilibrium conditions to analysis the force condition. Experiment evaluates the high load capacity, stability of the new grasping mode and displays the versatility of the STU hand. The STU hand has a wide range of applications especially in unstructured environment.展开更多
Cu−2Cr−1Nb alloy was fabricated by spark plasma sintering(SPS)using close coupled argon-atomized alloy powder as the raw material.The optimal SPS parameters obtained using the L9(3^(4))orthogonal test were 950℃,50 MP...Cu−2Cr−1Nb alloy was fabricated by spark plasma sintering(SPS)using close coupled argon-atomized alloy powder as the raw material.The optimal SPS parameters obtained using the L9(3^(4))orthogonal test were 950℃,50 MPa and 15 min,and the relative density of the as-sintered alloy was 99.8%.The rapid densification of SPS effectively inhibited the growth of the Cr_(2)Nb phase,and the atomized powder microstructure was maintained in the grains of the alloy matrix.Uniformly distributed multi-scale Cr_(2)Nb phases with grain sizes of 0.10−0.40μm and 20−100 nm and fine grains of alloy matrix with an average size of 3.79μm were obtained.After heat treatment at 500℃ for 2 h,the room temperature tensile strength,electrical conductivity,and thermal conductivity of the sintered Cu−2Cr−1Nb alloy were 332 MPa,86.7%(IACS),and 323.1 W/(m·K),respectively,and the high temperature tensile strength(700℃)was 76 MPa.展开更多
Animal and clinical studies have confirmed the therapeutic effect of bone marrow mesenchymal stem cells on cerebral ischemia, but their mechanisms of action remain poorly understood. Here, we summarize the transplanta...Animal and clinical studies have confirmed the therapeutic effect of bone marrow mesenchymal stem cells on cerebral ischemia, but their mechanisms of action remain poorly understood. Here, we summarize the transplantation approaches, directional migration, differentiation, replacement, neural circuit reconstruction,angiogenesis, neurotrophic factor secretion, apoptosis, immunomodulation, multiple mechanisms of action,and optimization strategies for bone marrow mesenchymal stem cells in the treatment of ischemic stroke.We also explore the safety of bone marrow mesenchymal stem cell transplantation and conclude that bone marrow mesenchymal stem cell transplantation is an important direction for future treatment of cerebral ischemia. Determining the optimal timing and dose for the transplantation are important directions for future research.展开更多
基金Project(2018YFB1502500) supported by the National Key Research and Development Program of ChinaProject supported by State Key Laboratory of Powder Metallurgy,Central South University,China+1 种基金Projects(21506258,51774127) supported by the National Natural Science Foundation of ChinaProject(2019RS2067) supported by the Science and Technology Planning Project of Hunan Province,China
文摘Composite coatings consisting of carbon and polytetrafluoroethylene(PTFE) were prepared on Ti alloy substrate by a simple two-step process of hydrothermal and impregnation. The morphology, composition, hydrophobic and corrosion properties of the composite coatings were characterized by scanning electron microscopy(SEM), Fourier transform infrared spectroscopy(FTIR), water contact angle method, X-ray photoelectron spectroscopy(XPS) and electrochemical technique, respectively. The effect of PTFE content on the corrosion properties of the composite coatings was studied. It is found that the composite coating film exhibits a full coverage with uniformly distributed PTFE when 0.1 mol/L of glucose is used as carbon source and 20 wt.% PTFE suspension as impregnating solution. The coating with 20 wt.% PTFE has a good bonding strength with Ti plate and exhibits excellent hydrophobic property with a water contact angle of 142.3° as well as superior corrosion resistance with corrosion current density as low as 0.0045 μA/cm^2. With regard to its excellent hydrophobicity and corrosion resistance, the carbon-PTFE composite coating may find potential application in automobiles and metal corrosion industries.
基金This research was funded in part by the ERANET PerMed consortium“PerProGlio”(to J.W.B.and A.S.).
文摘Objective Pituitary adenomas(PAs)can adapt an aggressive phenotype by invading adjacent brain structures with rapid cellular proliferation.Previous studies demonstrated that excessive expression of metalloproteases ADAM12 and MMP-14 is instrumental for the active proliferation and invasiveness of PA cells in vitro and of tumors in vivo.However,the mechanisms regulating ADAM12 and MMP-14 expression in PAs remain unclear.Methods Target gene prediction and transcriptomic profiling of invasive vs.noninvasive human PA samples were performed to identify miRNA species potentially involved in the regulation of ADAM12 and MMP14.For cellular analyses of miRNA functions,two mouse PA cell lines(AtT20 and TtT/GF)were transfected with miR-149-3p and miR-149-5p,respectively.The effects of miR-149(3p and 5p)on expression levels of ADAM12 and MMP14 were determined by Western blotting followed by an analysis of proliferation and colony formation assays,scratch migration assays,and invasion assays.Results A significant downregulation of miRNA-149 was observed in invasive vs.noninvasive PA(0.32 vs.0.09,P<0.0001).In AtT-20 and TtT/GF mouse PAs cells,transfection of mimic miRNA-149(3p and 5p)caused a significantly reduced cell proliferation and matrigel invasion,whilst the effect on cell migration was less pronounced.Both strands of miRNA-149(3p and 5p)markedly reduced protein levels of ADAM12 and MMP-14 by at least 40%in both cell lines.Conclusion This study proved that the invasiveness of PA cells is,at least partly,regulated by miRNA-149-dependent expression of ADAM12 and MMP-14.
基金This work was supported by the National Natural Science Youth Foundation of China(No.81602204).
文摘Objective Pituitary adrenocorticotropic hormone(ACTH)-secreting adenoma is a relatively intractable endocrine adenoma that can cause a range of severe metabolic disorders and pathological changes involving multiple systems.Previous studies have shown that celastrol has antitumor effects on a variety of tumor cells via the AKT/mTOR signaling.However,whether celastrol has pronounced antitumor effects on pituitary ACTH-secreting adenoma is unclear.This study aimed to identify a new effective therapeutic drug for pituitary ACTH-secreting adenoma.Methods Mouse pituitary ACTH-secreting adenoma cells(AtT20 cells)were used as an experimental model in vitro and to establish a xenograft tumor model in mice.Cells and animals were administered doses of celastrol at various levels.The effects of celastrol on cell viability,migration,apoptosis and autophagy were then examined.Finally,the potential involvement of AKT/mTOR signaling in celastrol’s mechanism was assessed.Results Celastrol inhibited the proliferation and migration of pituitary adenoma cells in a time-and concentration-dependent manner.It blocked AtT20 cells in the G0/G1 phase,and induced apoptosis and autophagy by downregulating the AKT/mTOR signaling pathway.Similar results were obtained in mice.Conclusion Celastrol exerts potent antitumor effects on ACTH-secreting adenoma by downregulating the AKT/mTOR signaling in vitro and in vivo.
基金Project supported by the National Natural Science Foundation of China (Grant No.11974379)the National Key Basic Research and Development Program of China (Grant No.2021YFC2203400)Jiangsu Vocational Education Integrated Circuit Technology “Double-Qualified” Famous Teacher Studio (Grant No.2022-13)。
文摘Graphene, with its zero-bandgap electronic structure, is a highly promising ultra-broadband light absorbing material.However, the performance of graphene-based photodetectors is limited by weak absorption efficiency and rapid recombination of photoexcited carriers, leading to poor photodetection performance. Here, inspired by the photogating effect, we demonstrated a highly sensitive photodetector based on graphene/WSe_(2) vertical heterostructure where the WSe_(2) layer acts as both the light absorption layer and the localized grating layer. The graphene conductive channel is induced to produce more carriers by capacitive coupling. Due to the strong light absorption and high external quantum efficiency of multilayer WSe_(2), as well as the high carrier mobility of graphene, a high photocurrent is generated in the vertical heterostructure. As a result, the photodetector exhibits ultra-high responsivity of 3.85×10~4A/W and external quantum efficiency of 1.3 × 10~7%.This finding demonstrates that photogating structures can effectively enhance the sensitivity of graphene-based photodetectors and may have great potential applications in future optoelectronic devices.
基金This study was funded by the National Key R&D Program of China(2016YFC0600301,2018YFC1503400)the National Natural Science Foundation of China(41790464)+1 种基金Natural Science Foundation of Jiangsu Province of China(BK20190499)the Fundamental Research Funds for the Central Universities(2019B0071428).
文摘The ratio between vertical and radial amplitudes of Rayleigh waves(hereafter,the Rayleigh wave ZH ratio)is an important parameter used to constrain structures beneath seismic stations.Some previous studies have explored crust and upper mantle structures by joint inversion of the Rayleigh wave ZH ratio and surface wave dispersion.However,all these studies have used a 1-D depth sensitivity kernel,and this kernel may lack precision when the structure varies a great deal laterally.Here,we present a systematic investigation of the two-dimensional(2-D)Rayleigh wave ZH ratio kernel based on the adjoint-wavefield method and perform two synthetic tests using the new kernel.The 2-D ZH ratio kernel is consistent with the traditional 1-D sensitivity kernel but has an asymmetric pattern with a preferred orientation toward the source.The predominant effect caused by heterogeneity can clearly be seen from kernels calculated from models with 2-D heterogeneities,which confirms the necessity of using the new 2-D kernel in some complex regions.Inversion tests using synthetic data show that the 2-D ZH ratio kernel has the potential to resolve small anomalies as well as complex lateral structures.
文摘Objective： To investigate the role of tissue factor （TF） in chemotherapeutic reagent - induced apoptosis on human glioblastoma and explore its mechanism. Methods： The expression of TF was examined by Western blotting. The cytotoxicity of doxorubicin was determined by WST assay. The activation of Caspase-3 and PARP induced by adoxorubicin were tested by Western blotting. Results： Human glioblastoma cell line U373MG expressed high level of TF while LN-229 was with low-TF level. The chemotherapeutic reagent doxorubicin revealed stronger cytotoxic effect on high-TF U373MG cells than IowoTF LN-229 cells. Enforced strong expression of TF was achieved by transfection of TF-pcDNA3 combinant on LN-229 cells in a dose-dependent manner. Enforced TF expression in transfected LN-229 cells not only impaired the doxorubicin-induced cleavage of Caspase-3 and PARP, but also inhibited the cytotoxic effect of doxorubicin. Furthermore, activation of Akt was strong in high-TF U373MG cells but weak in IowoTF LN-229 cells. Incubation of factor VII （FVII） with enforced TF-expressing LN-229 cells increased the phosphorylaUon of Akt in a time-dependent manner. Conclusion： These results suggest that over-expression of TF on glioblastoma could inhibit doxorubicin-induced apoptosis. Interaction of FVII and TF activates the downstream PI3K/Akt pathway. Tumor-derived over-expression of TF might play a role in chemotherapy resistance in glioblastoma, at lest in part, by activating PI3K/Akt-mediated survival and anti-apoptotic mechanism through the interaction of TF/FVII signaling.
基金This work was financially supported by“High-Level Youth Talent Special Support Plan”of Kunming City(C202014002)the National Natural Science Foundation of China(51904137)+3 种基金the Applied Basic Research Projects of Yunnan Province(2019FD044)the Open Projects of State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization(CNMRCUKF1905)the Talent Training Project of Kunming University(YJL2102)The authors are grateful to NSFC and“High-Level Talent Special Support Plan”of Kunming City(C201905002).
文摘The distribution of titanium,carbon and associated elements(calcium,magnesium,silicon and aluminum)in a smelting process is studied by means of a chemical equilibrium calculation method for multiphase and multicomponent systems,and verified through comparison with production results.In particular,using the coexistence theory for titanium slag structures,the influence of the AIR(anthracite to ilmenite ratio)on the distribution of such elements is analyzed.The results show that the AIR can be adjusted to achieve a selective reduction of oxides in the melt.
基金National Natural Science Foundation of China,31860098,Fu-Sheng Wang,82260679,Fu-Sheng Wang。
文摘Triplostegia glandulifera Wall(T.glandulifera)is an ethnomedicine commonly used by ethnic minorities in Yunnan,China,to treat kidney disease.However,there are few reports on the renoprotective effects of this substance,and the active ingredients remain unclear.In this study,we extracted the polysaccharide fractions TGB and TGC using the water extraction-alcohol precipitation method and determined their molecular weight(Mw)and monosaccharide composition.The study investigated the protective effects of TGB and TGC fractions against diabetic nephropathy(DN)using an in vitro high glucose-induced HRMCs model and an in vivo STZ-induced diabetic mouse model.HPLC analysis revealed that TGB contained D-galacturonic acid,D-glucose,D-galactose,and D-arabinose,and had a lower Mw than TGC.In vitro,TGB showed concentration-dependent antioxidant activity and effectively reduced abnormal proliferation and while attenuating oxidative stress in HRMCs.In mice with diabetes,TGB corrected the dysregulation of glucose-lipid metabolism and alleviated oxidative stress in the kidneys.Additionally,it improved renal function and reduced renal tissue damage.The study suggests that the low Mw polysaccharides(TGB)have better activity against DN through the antioxidative stress mechanism.
基金supported by the National Natural Science Foundation of China(No.82360437)the Key Research and Development Program of Hunan Province(No.2021SK2012).
文摘Volatile organic chemicals(VOC)have been identified as hazardous pollutants impairing human health.While whether the VOC exposure was associated with hyperuricemia is yet clarified.All the data was acquired from 6 survey cycles of the National Health and Nutrition Examination Survey(NHANES)program(2005–2006,2011–2012,2013–2014,2015–2016,2017–2018,2017–2020).Hyperuricemia was defined as a serum uric acid(SUA)concentration exceeding 7 mg/mL in men or 6 mg/mL in women.Three quantile logistic regression modelswith varied covariateswere developed to analyze the correlation between hyperuricemia and volatile organic chemical metabolites(VOCs)in urine,and three quantile linear regression models were used for examining the correlation between VOCs and SUA.N-acetyl-S-(2-carboxyethyl)-l-cysteine(CEMA),N-acetyl-S-(3,4-dihydroxybutyl)-l-cysteine(DHBM),and phenylglyoxylic acid(PHGA)were identified to associated positively with increased hyperuricemia risk and uric acid level.Meanwhile,the weighted quantile sum(WQS)model suggested a positive association between VOCs exposure and hyperuricemia.These data indicate that VOC exposure potentially increases hyperuricemia risk,necessitating policies to mitigate VOC exposure.
基金National Key Research and Development Program of China(2023YFC2505900)National Natural Science Foundation of China(92269204,82171755,92369106,82171749,82171811,82073184)+1 种基金Military Outstanding Youth Program(2020QN06119,01-SWK JYCJJ07,23SWAQ53)Program of Leading Talents in Shanghai,and Shanghai Shuguang Program(20SG39)。
文摘Background Liver ischemia/reperfusion(I/R)injury is usually caused by hepatic inflow occlusion during liver surgery,and is frequently observed during war wounds and trauma.Hepatocyte ferroptosis plays a critical role in liver I/R injury,however,it remains unclear whether this process is controlled or regulated by members of the DEAD/DExH-box helicase(DDX/DHX)family.Methods The expression of DDX/DHX family members during liver I/R injury was screened using transcriptome analysis.Hepatocyte-specific Dhx58 knockout mice were constructed,and a partial liver I/R operation was performed.Single-cell RNA sequencing(scRNA-seq)in the liver post I/R suggested enhanced ferroptosis by Dhx58hep−/−.The mRNAs and proteins associated with DExH-box helicase 58(DHX58)were screened using RNA immunoprecipitation-sequencing(RIP-seq)and IP-mass spectrometry(IP-MS).Results Excessive production of reactive oxygen species(ROS)decreased the expression of the IFN-stimulated gene Dhx58 in hepatocytes and promoted hepatic ferroptosis,while treatment using IFN-αincreased DHX58 expression and prevented ferroptosis during liver I/R injury.Mechanistically,DHX58 with RNA-binding activity constitutively associates with the mRNA of glutathione peroxidase 4(GPX4),a central ferroptosis suppressor,and recruits the m6A reader YT521-B homology domain containing 2(YTHDC2)to promote the translation of Gpx4 mRNA in an m6A-dependent manner,thus enhancing GPX4 protein levels and preventing hepatic ferroptosis.Conclusions This study provides mechanistic evidence that IFN-αstimulates DHX58 to promote the translation of m6A-modified Gpx4 mRNA,suggesting the potential clinical application of IFN-αin the prevention of hepatic ferroptosis during liver I/R injury.
基金supported by the National Key Research and Development Program of China(No.2022YFC3701000)the National Natural Science Foundation of China(Nos.42130606 and 41931287)+1 种基金the Beijing National Laboratory for Molecular Sciences(BNLMS-CXXM-202011)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.Y2021013).
文摘With the rapid development of the world economy,complex air pollution has increasingly become a serious threat;for example,with haze events occurring frequently in various regions of the globe.Recent evidence has indicated that secondary aerosols play an important role in haze formation,and that heterogeneous processes are among the main forces driving their explosive growth.In this regard,this paper reviews recent advances in the understanding of the impact of heterogeneous processes on haze chemistry,including the impact on NO_(2)chemistry,marine aerosols,and the hygroscopicity and optical properties of atmospheric aerosols.It is distinguished from past reviews on this topic by focusing mainly on new insights from the past five years.We summarize the main findings of the impacts of heterogeneous processes on NO_(2)chemistry,marine aerosols,and the physicochemical properties of atmospheric aerosols,and propose several future research directions.
文摘共轭高分子材料具有质轻、柔软、成本低、性能易于调控且可溶液加工等特点,在有机电致发光二极管、有机光伏、场效应晶体管与传感器件等领域有广泛的应用前景.共轭高分子体系中的多种弱相互作用使其可以形成复杂的多级组装结构,因此深入研究共轭高分子多级组装对于明确高分子功能材料构效关系具有重要意义.本文立足于系统对比共轭高分子多级组装与蛋白质多级组装的相似性,首次划分了共轭高分子多级组装中存在的四级结构:一级结构为通过共价作用形成的一维聚合物链结构,二级结构为通过分子间相互作用如π-π堆积(π-πstacking)、层状堆叠(lamellar packing)和链缠结等形成的一条或多条聚合物链组装结构,三级结构为不同相行为对应的聚集结构,例如结晶、无定形区域(crystalline and amorphous region)和过渡区域等,四级结构为多组分相互作用及相分离的材料体系.多级结构相互关联,共同决定了共轭高分子材料的光、电、热等物理性质.本文总结了近年来共轭高分子多级组装的相关研究工作,为观察和理解并指导高分子多级组装、建立完整的"构效"关系、优化器件性能提供了新视角.
基金supported by a grant from the Health and Family Planning Commission of Heilongjiang Province Research Project in China,No.2014-195the Education Department Science and Technology Foundation of Heilongjiang Province in China,No.12531741the Natural Science Foundation of Heilongjiang Province of China,No.H2015083
文摘Ligustrazine （2,3,5,6-tetramethylpyrazine） is a major active ingredient of the Szechwan lovage rhizome and is extensively used in treatment of ischemic cerebrovascular disease. The mecha- nism of action of ligustrazine use against ischemic cerebrovascular diseases remains unclear at present. This study summarizes its protective effect, the optimum time window of administra- tion, and the most effective mode of administration for clinical treatment of cerebral ischemia/ reperfusion injury. We examine the effects of ligustrazine on suppressing excitatory amino acid release, promoting migration, differentiation and proliferation of endogenous neural stem cells. We also looked at its effects on angiogenesis and how it inhibits thrombosis, the inflammatory response, and apoptosis after cerebral ischemia. We consider that ligustrazine gives noticeable protection from cerebral ischemia/reperfusion injury. The time window of ligustrazine admin- istration is limited. The protective effect and time window of a series of derivative monomers of ligustrazine such as 2-[（1,1-dimethylethyl）oxidoimino]methyl]-3,5,6-trimethylpyrazine, CXC137 and CXC 195 after cerebral ischemia were better than ligustrazine.
文摘The latest edition of the WHO classification of the central nervous system was published in 2021.This review summarizes the major revisions to the classification of anterior pituitary tumors.The most important revision involves preferring the terminology of pituitary neuroendocrine tumor(PitNET),even though the terminology of pituitary adenoma(PA)still can be used according to this WHO classification compared to the previous one.Moreover,immunohistochemistry(IHC)examination of pituitary-specific transcription factors(TFs),including PIT1,TPIT,SF-1,GATA2/3,and ERα,is endorsed to determine the tumor cell lineage and to facilitate the classification of PitNET/PA subgroups.However,TF-negative IHC staining indicates PitNET/PA with no distinct cell lineages,which includes unclassified plurihormonal(PH)tumors and null cell(NC)tumors in this edition.The new WHO classification of PitNET/PA has incorporated tremendous advances in the understanding of the cytogenesis and pathogenesis of pituitary tumors.However,due to the shortcomings of the technology used in the diagnosis of PitNET/PA and the limited understanding of the tumorigenesis of PitNET/PA,the application of this new classification system in practice should be further evaluated and validated.Besides providing information for deciding the follow-up plans and adjunctive treatment after surgery,this classification system offers no additional help for neurosurgeons in clinical practice,especially in determining the treatment strategies.Therefore,it is necessary for neurosurgeons to establish a comprehensive pituitary classification system for PitNET/PA that incorporates neuroimaging grading data or direct observation of invasiveness during operation or the predictor of prognosis,as well as pathological diagnosis,thereby distinguishing the invasiveness of the tumor and facilitating neurosurgeons to decide on the treatment strategies and follow-up plans as well as adjunctive treatment after surgery.
基金National Natural Science Foundation of China(Grant Nos.U1613216,61573333)
文摘Robot hands have been developing during the last few decades. There are many mechanical structures and analyti?cal methods for di erent hands. But many tough problems still limit robot hands to apply in homelike environment. The ability of grasping objects covering a large range of sizes and various shapes is fundamental for a home service robot to serve people better. In this paper, a new grasping mode based on a novel sucked?type underactuated(STU) hand is proposed. By combining the flexibility of soft material and the e ect of suction cups, the STU hand can grasp objects with a wide range of sizes, shapes and materials. Moreover, the new grasping mode is suitable for some situations where the force closure is failure. In this paper, we deduce the e ective range of sizes of objects which our hand using the new grasping mode can grasp. Thanks to the new grasping mode, the ratio of grasping size between the biggest object and the smallest is beyond 40, which makes it possible for our robot hand to grasp diverse objects in our daily life. For example, the STU hand can grasp a soccer(220 mm diameter, 420 g) and a fountain pen(9 mm diameter, 9 g). What’s more, we use the rigid body equilibrium conditions to analysis the force condition. Experiment evaluates the high load capacity, stability of the new grasping mode and displays the versatility of the STU hand. The STU hand has a wide range of applications especially in unstructured environment.
基金financially supported by the National Key Research and Development Program of China (No.2016YFB0301300)Innovation Driven Project of Central South University,China (No.2015CX004)+1 种基金State Key Laboratory of Powder Metallurgy,Central South University,Chinathe Open Fund of National Joint Engineering Research Center for Abrasion Control and Molding of Metal Materials,China (No.HKDNM201907)。
文摘Cu−2Cr−1Nb alloy was fabricated by spark plasma sintering(SPS)using close coupled argon-atomized alloy powder as the raw material.The optimal SPS parameters obtained using the L9(3^(4))orthogonal test were 950℃,50 MPa and 15 min,and the relative density of the as-sintered alloy was 99.8%.The rapid densification of SPS effectively inhibited the growth of the Cr_(2)Nb phase,and the atomized powder microstructure was maintained in the grains of the alloy matrix.Uniformly distributed multi-scale Cr_(2)Nb phases with grain sizes of 0.10−0.40μm and 20−100 nm and fine grains of alloy matrix with an average size of 3.79μm were obtained.After heat treatment at 500℃ for 2 h,the room temperature tensile strength,electrical conductivity,and thermal conductivity of the sintered Cu−2Cr−1Nb alloy were 332 MPa,86.7%(IACS),and 323.1 W/(m·K),respectively,and the high temperature tensile strength(700℃)was 76 MPa.
基金supported by the Natural Science Foundation of Heilongjiang Province of China,No.H2015083a grant from Higher Education Reform Project of Mudanjaing Medical University of China,No.2013016
文摘Animal and clinical studies have confirmed the therapeutic effect of bone marrow mesenchymal stem cells on cerebral ischemia, but their mechanisms of action remain poorly understood. Here, we summarize the transplantation approaches, directional migration, differentiation, replacement, neural circuit reconstruction,angiogenesis, neurotrophic factor secretion, apoptosis, immunomodulation, multiple mechanisms of action,and optimization strategies for bone marrow mesenchymal stem cells in the treatment of ischemic stroke.We also explore the safety of bone marrow mesenchymal stem cell transplantation and conclude that bone marrow mesenchymal stem cell transplantation is an important direction for future treatment of cerebral ischemia. Determining the optimal timing and dose for the transplantation are important directions for future research.
