Ischemic stroke,which is characterized by hypoxia and ischemia,triggers a cascade of injury responses,including neurotoxicity,inflammation,oxidative stress,disruption of the blood-brain barrier,and neuronal death.In t...Ischemic stroke,which is characterized by hypoxia and ischemia,triggers a cascade of injury responses,including neurotoxicity,inflammation,oxidative stress,disruption of the blood-brain barrier,and neuronal death.In this context,tryptophan metabolites and enzymes,which are synthesized through the kynurenine and 5-hydroxytryptamine pathways,play dual roles.The delicate balance between neurotoxic and neuroprotective substances is a crucial factor influencing the progression of ischemic stroke.Neuroprotective metabolites,such as kynurenic acid,exert their effects through various mechanisms,including competitive blockade of N-methyl-D-aspartate receptors,modulation ofα7 nicotinic acetylcholine receptors,and scavenging of reactive oxygen species.In contrast,neurotoxic substances such as quinolinic acid can hinder the development of vascular glucose transporter proteins,induce neurotoxicity mediated by reactive oxygen species,and disrupt mitochondrial function.Additionally,the enzymes involved in tryptophan metabolism play major roles in these processes.Indoleamine 2,3-dioxygenase in the kynurenine pathway and tryptophan hydroxylase in the 5-hydroxytryptamine pathway influence neuroinflammation and brain homeostasis.Consequently,the metabolites generated through tryptophan metabolism have substantial effects on the development and progression of ischemic stroke.Stroke treatment aims to restore the balance of various metabolite levels;however,precise regulation of tryptophan metabolism within the central nervous system remains a major challenge for the treatment of ischemic stroke.Therefore,this review aimed to elucidate the complex interactions between tryptophan metabolites and enzymes in ischemic stroke and develop targeted therapies that can restore the delicate balance between neurotoxicity and neuroprotection.展开更多
目的:研究促结缔组织增生性小圆细胞肿瘤(desmoplastic small round cell tumor,DSRCT)的临床病理特征。方法:回顾性分析2012年1月至2019年11月7例首都医科大学附属北京世纪坛医院诊断的DSRCT临床资料,复阅病理切片,并行免疫组织化学法...目的:研究促结缔组织增生性小圆细胞肿瘤(desmoplastic small round cell tumor,DSRCT)的临床病理特征。方法:回顾性分析2012年1月至2019年11月7例首都医科大学附属北京世纪坛医院诊断的DSRCT临床资料,复阅病理切片,并行免疫组织化学法及荧光原位杂交法(fluorescence in situ hybridization,FISH)检测,总结病理特征。结果:患者均为男性,中位年龄29岁,部位均为腹腔,临床症状包括腹胀腹痛、腹水、大便习惯改变、排尿困难。病理大体上表现为大网膜或肠系膜多发灰白结节,组织学上表现为大小不一、形态不规则的小圆细胞巢及增生的纤维结缔组织。免疫组织化学法检测显示肿瘤细胞中的Desmin和Vimentin呈核旁点灶状阳性表达,FISH检测EWSR1-WT1融合基因阳性。中位随访期为15个月,6例生存,1例死亡。结论:DSRCT发病率低,高度恶性,Desmin和Vimentin核旁点灶状阳性表达具有提示意义,EWSR1-WT1融合基因阳性具有确诊意义。展开更多
Shear strength is an essential geotechnical parameter for assessing the landslide potential of loess slopes under rainfall infiltration and farm irrigation conditions on the loess plateau.However,the hydraulic path de...Shear strength is an essential geotechnical parameter for assessing the landslide potential of loess slopes under rainfall infiltration and farm irrigation conditions on the loess plateau.However,the hydraulic path dependence of shear strength for compacted loess under varying rainfall infiltration conditions has not been thoroughly investigated yet.To this end,a series of direct shear tests and nuclear magnetic resonance(NMR)measurements are carried out on compacted loess.The shear strength tests were continuously implemented on loess specimens under scanning wetting paths besides initial drying paths.The experimental data quantitatively verify the significant effect of hydraulic paths applied to specimens on shear strength of compacted loess.The unique failure envelope of shear strength of loess is identified under the effective stress framework based on intergranular stress,which verifies that the effective stress framework can consider the effect of hydraulic paths on shear strength.Based on the effective stress,a shear strength formula is proposed to characterize shear strengths under varying hydraulic paths,in which the parameters from the soil-water retention curve and shear strength at saturated state are simply required.The proposed shear strength formula can properly predict the measured shear strength data of compacted loess experiencing three hydraulic paths.Furthermore,the distribution curves of transverse relaxation time for pore water in soil under varying hydraulic paths are simultaneously measured using the NMR method.The physical mechanism for the difference in shear strength of loess subjected to different hydraulic paths can be uncovered based on soil-water evolutions in pores in microscale.展开更多
Most previously reported inertia actuators suffer from the problems of low speed and large size.To overcome these shortcomings,this study proposes a slim compact piezo inertia actuator based on the principle of stick...Most previously reported inertia actuators suffer from the problems of low speed and large size.To overcome these shortcomings,this study proposes a slim compact piezo inertia actuator based on the principle of stick–slip drive.Actuated by the transverse motion of a cantilever beam forming part of a monolithic elastomer,this actuator achieves a high velocity.The construction and basic operating principle of the actuator are discussed in detail.Commercial finite element analysis software is employed to determine the appropriate geometry for the monolithic elastomer.To study the actuator’s mechanical characteristics,a prototype is fabricated and a series of experimental tests are performed.According to the results of these tests,the maximum velocity and maximum load force are about 24.03 mm/s and 1.96 N,respectively,and the minimum step size is about 0.47μm.It is shown that the inertia actuator based on a monolithic elastomer with a cantilever beam not only has a slim compact structure,but also exhibits good output characteristics.展开更多
Deep understanding of the fluorescence quenching mechanisms of probes plays a crucial role in developing their practical applications.The fluorescence quenching mechanism of hydrazine-based fluorescence probes needs t...Deep understanding of the fluorescence quenching mechanisms of probes plays a crucial role in developing their practical applications.The fluorescence quenching mechanism of hydrazine-based fluorescence probes needs to be clarified up to the present.Herein,we designed and synthesized a new hydrazine-based fluorescence probe(HA-Na)based on the naphthalimide skeleton.We clarified the molecular origin of the non-fluorescence of this probe with the aid of computational chemistry and spectroscopic analysis.We showed that the significant rotation of the hydrazine group in the excited state potential energy surface,which caused the complete charge separation,was responsible for the fluorescence quenching of the probe in an organic solvent.Once the rotation was prevented in an aggregative state or high-viscosity solution,the fluorescence of the probe recovered.In other words,the fluorescence quenching mechanism of hydrazine-based fluorescence probes was attributed to the formation of a twisted intramolecular charge transfer(TICT)state.More importantly,we demonstrated that this fluorescence molecular rotor could be used to monitor the autophagy process in living cells by detecting lysosomal viscosity changes during starvation.Altogether,this work provides an essential theoretical basis for the developing potential hydrazine-based fluorescence molecular rotors.展开更多
The former gas pipeline operating pressure transmission determined mostly according to the determined formula into the corresponding pipeline parameters are obtained, and the parameters of the actual pipeline due to m...The former gas pipeline operating pressure transmission determined mostly according to the determined formula into the corresponding pipeline parameters are obtained, and the parameters of the actual pipeline due to many reasons, such as measurement error, production batch, etc., is not a fixed value. This paper on pipeline integrity established limit state equation, using Monte Carlo method to calculate the gas pipeline in different pressures of reliability, according to the API （American Petroleum Institute） 579 recommended target reliability to determine the operating pressure of the different regions, and design coefficient method, the calculated results are compared, results of calculation reliability is more reasonable and improve the delivery pressure of the area, the pipeline safety management provides the basis.展开更多
基金supported by Shanghai Shenkang Center Demonstration Research Ward Construction,No.SHDC2022CRW010(to MF)Shanghai Shenkang Center Medical Enterprise Integration and Innovation Collaborative Special Project,No.SHDC2022CRT018(to MF)+4 种基金Shanghai Health System Key Supported Discipline-Rehabilitation Medicine,No.2023ZDFC0301(to JT)Science and Technology Development Project of Shanghai University of Traditional Chinese Medicine,No.23KFL009(to JT)Shanghai Postdoctoral Excellence Program,No.2022515(to CY)Yangfan Special Project of Shanghai Science and Technology Innovation Action Plan,No.23YF1447600(to CY)China Postdoctoral Science Foundation,No.2023M732338(to CY).
文摘Ischemic stroke,which is characterized by hypoxia and ischemia,triggers a cascade of injury responses,including neurotoxicity,inflammation,oxidative stress,disruption of the blood-brain barrier,and neuronal death.In this context,tryptophan metabolites and enzymes,which are synthesized through the kynurenine and 5-hydroxytryptamine pathways,play dual roles.The delicate balance between neurotoxic and neuroprotective substances is a crucial factor influencing the progression of ischemic stroke.Neuroprotective metabolites,such as kynurenic acid,exert their effects through various mechanisms,including competitive blockade of N-methyl-D-aspartate receptors,modulation ofα7 nicotinic acetylcholine receptors,and scavenging of reactive oxygen species.In contrast,neurotoxic substances such as quinolinic acid can hinder the development of vascular glucose transporter proteins,induce neurotoxicity mediated by reactive oxygen species,and disrupt mitochondrial function.Additionally,the enzymes involved in tryptophan metabolism play major roles in these processes.Indoleamine 2,3-dioxygenase in the kynurenine pathway and tryptophan hydroxylase in the 5-hydroxytryptamine pathway influence neuroinflammation and brain homeostasis.Consequently,the metabolites generated through tryptophan metabolism have substantial effects on the development and progression of ischemic stroke.Stroke treatment aims to restore the balance of various metabolite levels;however,precise regulation of tryptophan metabolism within the central nervous system remains a major challenge for the treatment of ischemic stroke.Therefore,this review aimed to elucidate the complex interactions between tryptophan metabolites and enzymes in ischemic stroke and develop targeted therapies that can restore the delicate balance between neurotoxicity and neuroprotection.
文摘目的:研究促结缔组织增生性小圆细胞肿瘤(desmoplastic small round cell tumor,DSRCT)的临床病理特征。方法:回顾性分析2012年1月至2019年11月7例首都医科大学附属北京世纪坛医院诊断的DSRCT临床资料,复阅病理切片,并行免疫组织化学法及荧光原位杂交法(fluorescence in situ hybridization,FISH)检测,总结病理特征。结果:患者均为男性,中位年龄29岁,部位均为腹腔,临床症状包括腹胀腹痛、腹水、大便习惯改变、排尿困难。病理大体上表现为大网膜或肠系膜多发灰白结节,组织学上表现为大小不一、形态不规则的小圆细胞巢及增生的纤维结缔组织。免疫组织化学法检测显示肿瘤细胞中的Desmin和Vimentin呈核旁点灶状阳性表达,FISH检测EWSR1-WT1融合基因阳性。中位随访期为15个月,6例生存,1例死亡。结论:DSRCT发病率低,高度恶性,Desmin和Vimentin核旁点灶状阳性表达具有提示意义,EWSR1-WT1融合基因阳性具有确诊意义。
基金supported by the National Natural Science Foundation of China(Grant Nos.41877269,12002243,41907046).
文摘Shear strength is an essential geotechnical parameter for assessing the landslide potential of loess slopes under rainfall infiltration and farm irrigation conditions on the loess plateau.However,the hydraulic path dependence of shear strength for compacted loess under varying rainfall infiltration conditions has not been thoroughly investigated yet.To this end,a series of direct shear tests and nuclear magnetic resonance(NMR)measurements are carried out on compacted loess.The shear strength tests were continuously implemented on loess specimens under scanning wetting paths besides initial drying paths.The experimental data quantitatively verify the significant effect of hydraulic paths applied to specimens on shear strength of compacted loess.The unique failure envelope of shear strength of loess is identified under the effective stress framework based on intergranular stress,which verifies that the effective stress framework can consider the effect of hydraulic paths on shear strength.Based on the effective stress,a shear strength formula is proposed to characterize shear strengths under varying hydraulic paths,in which the parameters from the soil-water retention curve and shear strength at saturated state are simply required.The proposed shear strength formula can properly predict the measured shear strength data of compacted loess experiencing three hydraulic paths.Furthermore,the distribution curves of transverse relaxation time for pore water in soil under varying hydraulic paths are simultaneously measured using the NMR method.The physical mechanism for the difference in shear strength of loess subjected to different hydraulic paths can be uncovered based on soil-water evolutions in pores in microscale.
基金supported by a Specialized Research Fund(Grant No.923801).
文摘Most previously reported inertia actuators suffer from the problems of low speed and large size.To overcome these shortcomings,this study proposes a slim compact piezo inertia actuator based on the principle of stick–slip drive.Actuated by the transverse motion of a cantilever beam forming part of a monolithic elastomer,this actuator achieves a high velocity.The construction and basic operating principle of the actuator are discussed in detail.Commercial finite element analysis software is employed to determine the appropriate geometry for the monolithic elastomer.To study the actuator’s mechanical characteristics,a prototype is fabricated and a series of experimental tests are performed.According to the results of these tests,the maximum velocity and maximum load force are about 24.03 mm/s and 1.96 N,respectively,and the minimum step size is about 0.47μm.It is shown that the inertia actuator based on a monolithic elastomer with a cantilever beam not only has a slim compact structure,but also exhibits good output characteristics.
基金supported by the Hainan Provincial Natural Science Foundation of China(123MS001 and 123QN181)the National Natural Science Foundation of China(32360236,52063011,22203024)+2 种基金the Collaborative Innovation Center Foundation of the Hainan University(XTCX2022JKB03)the Research Start-up Fund Project of Hainan University(No.RZ2200001217 and RZ2200001216)Tianjin University-Hainan University Independent Innovation Fund(RZ2200003795).
文摘Deep understanding of the fluorescence quenching mechanisms of probes plays a crucial role in developing their practical applications.The fluorescence quenching mechanism of hydrazine-based fluorescence probes needs to be clarified up to the present.Herein,we designed and synthesized a new hydrazine-based fluorescence probe(HA-Na)based on the naphthalimide skeleton.We clarified the molecular origin of the non-fluorescence of this probe with the aid of computational chemistry and spectroscopic analysis.We showed that the significant rotation of the hydrazine group in the excited state potential energy surface,which caused the complete charge separation,was responsible for the fluorescence quenching of the probe in an organic solvent.Once the rotation was prevented in an aggregative state or high-viscosity solution,the fluorescence of the probe recovered.In other words,the fluorescence quenching mechanism of hydrazine-based fluorescence probes was attributed to the formation of a twisted intramolecular charge transfer(TICT)state.More importantly,we demonstrated that this fluorescence molecular rotor could be used to monitor the autophagy process in living cells by detecting lysosomal viscosity changes during starvation.Altogether,this work provides an essential theoretical basis for the developing potential hydrazine-based fluorescence molecular rotors.
文摘The former gas pipeline operating pressure transmission determined mostly according to the determined formula into the corresponding pipeline parameters are obtained, and the parameters of the actual pipeline due to many reasons, such as measurement error, production batch, etc., is not a fixed value. This paper on pipeline integrity established limit state equation, using Monte Carlo method to calculate the gas pipeline in different pressures of reliability, according to the API （American Petroleum Institute） 579 recommended target reliability to determine the operating pressure of the different regions, and design coefficient method, the calculated results are compared, results of calculation reliability is more reasonable and improve the delivery pressure of the area, the pipeline safety management provides the basis.
