检索结果-南通市图书馆

Ace2, rather than ace1, is the major acetylcholinesterase in the silkworm, Bombyx moil

Insect Science 2009年第4期16卷 297-303页

作者： hui-juan Chen Zhen liao Xiao-Ming hui Guo-Qing Li Fei Li Zhao-Jun Han Department of Entomology Nanjing Agricultural University Nanjing China

Two acetylcholinesterase （ace） genes have been reported in many insect species. In pests such as Helicoverpa assulta and Plutella xylostellas, acel gene encodes the predominant synaptic enzyme that is the main target of organophosphorus （OP） and carbamate pesticides. It has been reported that pesticide selection has an impact on the ace gene evolution. The domesticated silkworm, Bombyx mori, also has two ace genes. We studied ace gene expression and enzyme activities in silkworm as this has not faced pesticide selection over the past decades. The expression levels of two ace genes, Bm-acel and Bm-ace2, were estimated by quantitative real-time polymerase chain reaction. Bin-ace2 was expressed more highly than Bm-acel in all tested samples of different developmental stages or tissues, suggesting ace2, rather than acel, is the major type ofacetylcholinesterase （ACHE） in Bombyx mori. This is inconsistent with the aforementioned lepidopterons agricultural pests, partly be due to the widespread use of pesticides that may induce high expression of the acel gene in these pests. Besides high expression in the head, Bm-acel also expresses highly in the silk glands and Bm-ace2 is abundant in the germline, implying both ace genes may have potential non-hydrolytic roles in development. Furthermore, we found that the mRNA levels of two ace genes and their ratios （ace2/acel） change day to day in the first and third instars. This challenges the conventional method of estimating enzymatic activity using crude extract as an enzyme solution, as it is a mixture of ACHE 1 and ACHE2. An efficient and simple method for separating different ACHEs is necessary for reliable toxicological analyses.

关键词： acetylcholinesterase Bombyx mori expression Kin quantitative real-time polymerase chain reaction (qRT-PCR)

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Silencing Huwe1 reduces apoptosis of cortical neurons exposed to oxygen-glucose deprivation and reperfusion

引用

Neural Regeneration Research 2019年第11期14卷 1977-1985页

作者： Guo-Qian He Wen-Ming Xu hui-juan liao Chuan Jiang Chang-Qing Li Wei Zhang Department of Pediatrics Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University)Ministry of EducationWest China Second University HospitalSichuan UniversityChengduSichuan ProvinceChina Joint Laboratory of Reproductive Medicine Key Laboratory of Birth Defects and Related Diseases of Women and Children (Sichuan University)Ministry of EducationWest China Second University HospitalSichuan UniversityChengduSichuan ProvinceChina Department of Neurology The Second Affiliated Hospital of Chongqing Medical UniversityChongqingChina Department of Medical Oncology Sichuan Cancer Hospital & InstituteSichuan Cancer CenterCancer Hospital Affiliated to School of MedicineUniversity of Electronic Science and Technology of ChinaChengduSichuan ProvinceChina

HECT, UBA and WWE domain-containing 1(Huwe1), an E3 ubiquitin ligase involved in the ubiquitin-proteasome system, is widely expressed in brain tissue. Huwe1 is involved in the turnover of numerous substrates, including p53, Mcl-1, Cdc6 and N-myc, thereby playing a critical role in apoptosis and neurogenesis. However, the role of Huwe1 in brain ischemia and reperfusion injury remains unclear. Therefore, in this study, we investigated the role of Huwe1 in an in vitro model of ischemia and reperfusion injury. At 3 days in vitro, primary cortical neurons were transduced with a control or shRNA-Huwe1 lentiviral vector to silence expression of Huwe1. At 7 days in vitro, the cells were exposed to oxygen-glucose deprivation for 3 hours and reperfusion for 24 hours. To examine the role of the c-Jun N-terminal kinase(JNK)/p38 pathway, cortical neurons were pretreated with a JNK inhibitor(SP600125) or a p38 MAPK inhibitor(SB203508) for 30 minutes at 7 days in vitro, followed by ischemia and reperfusion. Neuronal apoptosis was assessed by TUNEL assay. Protein expression levels of JNK and p38 MAPK and of apoptosis-related proteins(p53, Gadd45 a, cleaved caspase-3, Bax and Bcl-2) were measured by western blot assay. Immunofluorescence labeling for cleaved caspase-3 was performed. We observed a significant increase in neuronal apoptosis and Huwe1 expression after ischemia and reperfusion. Treatment with the shRNA-Huwe1 lentiviral vector markedly decreased Huwe1 levels, and significantly decreased the number of TUNEL-positive cells after ischemia and reperfusion. The silencing vector also downregulated the pro-apoptotic proteins Bax and cleaved caspase-3, and upregulated the anti-apoptotic proteins Gadd45 a and Bcl-2. Silencing Huwe1 also significantly reduced p-JNK levels and increased p-p38 levels. Our findings show that downregulating Huwe1 affects the JNK and p38 MAPK signaling pathways as well as the expression of apoptosis-related genes to provide neuroprotection during ische

关键词： nerve regeneration ischemic stroke oxygen-glucose deprivation and reperfusion ischemia/reperfusion cortical neuron ubiquitin proteasome system Huwe1 apoptosis therapeutic targets cell culture cell death neural regeneration

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Measurement of Frequency Shift Characteristics Based on LiNbO_3 Waveguide Electro-Optic Intensity Modulator

引用

Journal of Electronic Science and Technology of China 2008年第4期6卷 449-452页

作者： Zhou Meng hui-juan Zhou Yi liao Qiong Yao College ofOptoelectronic Science and Engineering National University of DefenseTechnology Changsha Hunan 410073 China

High-speed and wide-band LiNbO3 waveguide electro-optic intensity modulator has drawn great attention in the field of optical fiber communication and sensor. This paper reports the research results on the measurement of frequency shift characteristics of Mach-Zehnder electro-optic intensity modulator. Two measurement methods of frequency shift characteristics for high and low frequency modulations are studied in theory and experiment and demonstrate different results. The realization of a multi-wavelength optical source based on Mach-Zehnder electro-optic intensity modulator has been introduced. The technique to reach the maximum intensity for interesting shift frequency, particularly for heterodyne detection of Brillouin distributed optical fiber sensing, has been given.

关键词： Brillouin electro-optic intensity modulator frequency shift LiNbO3.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effect of pre-deformation on microstructures and mechanical properties of high purity Al-Cu-Mg alloy

引用

Transactions of Nonferrous Metals Society of China 2016年第6期26卷 1482-1490页

作者：李慧中刘若梅梁霄鹏邓敏廖慧娟黄岚中南大学材料科学与工程学院长沙410083 中南大学粉末冶金国家重点实验室长沙410083 中南大学有色金属材料科学与工程教育部重点实验室长沙410083

The effects of pre-deformation following solution treatment on the microstructure and mechanical properties of aged high purity Al-Cu-Mg alloy were studied by tensile test, micro-hardness measurements, transmission electron microscopy and scanning electron microscopy. The micro-hardness measurements indicate that compared with un-deformed samples, the peak hardness is increased and the time to reach peak hardness is reduced with increasing pre-strain. Additionally, a double-peak hardness evolution behavior of cold-rolled （CR） samples was observed during aging. The results of TEM observation show that the number density of S′（Al2CuMg） phase is increased and the size is decreased in CR alloy with increase of pre-strain. The peak hardness and peak strength of the CR alloy are increased because of quantity increasing and refinement of S′ phase and high density dislocation.

关键词： Al-Cu-Mg alloy pre-deformation age strengthening precipitation microstructure mechanical properties

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effect of aging time on corrosion behavior of as-forged AZ80 magnesium alloy

引用

Transactions of Nonferrous Metals Society of China 2015年第12期25卷 3921-3927页

作者：廖慧娟周效枫李慧中邓敏梁霄鹏刘若梅中南大学材料科学与工程学院长沙410083 中南大学粉末冶金国家重点实验室长沙410083 中南大学有色金属材料科学与工程教育部重点实验室长沙410083

The corrosion behaviors of an as-forged AZ80 magnesium alloy after aging treatment for various durations at 170 °C were investigated by immersion test, H2 evolution test, SEM and potentiodynamic polarization curve measurement. The results show that the corrosion rate of the alloy decreases dramatically with the increase of aging time during the initial aging stage, but increases slowly with the aging time longer than 20 h. The volume fraction of β-Mg17Al12 increases with aging time within the first 20 h, leading to the decrease of corrosion rate. After aging for longer than 39 h, the growth of β phase is accompanied by the consumption of aluminum in the matrix, resulting in an increase in the corrosion rate. When the volume fraction of ？ phase is low, specimens suffer from severe local corrosion, which results in a porous surface. On the contrary, when the volume fraction of ？ phase is high, specimens suffer uniform corrosion attack.

关键词： AZ80 magnesium alloy aging treatment corrosion

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Biomechanics of the sclera and effects on intraocular pressure

引用

International Journal of Ophthalmology(English edition) 2016年第12期9卷 1824-1831页

作者： Xu Jia juan Yu Sheng-hui liao Xuan-Chu Duan Department of Ophthalmology the Second Xiangya Hospital Central South University Changsha 410011 Hunan Province China Department of Ophthalmology the First Hospital of Hunan University of Chinese Medicine Changsha 410011 Hunan Province China School of Information Science and Engineering Central South University Changsha 410011 Hunan Province China

Accumulating evidence indicates that glaucoma is a multifactorial neurodegenerative disease characterized by the loss of retinal ganglion cells （RGC）, resulting in gradual and progressive permanent loss of vision. Reducing intraocular pressure （IOP） remains the only proven method for preventing and delaying the progression of glaucomatous visual impairment. However, the specific role of IOP in optic nerve injury remains controversial, and little is known about the biomechanical mechanism by which elevated IOP leads to the loss of RGC. Published studies suggest that the biomechanical properties of the sclera and scleral lamina cribrosa determine the biomechanical changes of optic nerve head, and play an important role in the pathologic process of loss of RGC and optic nerve damage. This review focuses on the current understanding of biomechanics of sclera in glaucoma and provides an overview of the possible interactions between the sclera and IOP. Treatments and interventions aimed at the sclera are also discussed.

关键词： biomechanics glaucoma sclera intraocular pressure finite element models

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Hot-cracking susceptibility and shear fracture behavior of dissimilar Ti6Al4V/AA6060 alloys in pulsed Nd:YAG laser welding

引用

Chinese Journal of Aeronautics 2021年第4期34卷 375-386页

作者： Xin XUE Xinyong WU juan liao School of Mechanical Engineering and Automation Fuzhou UniversityFuzhou 350116China Fujian Nebula Electronics Co. Ltd.Fuzhou 350015China

Laser welding of dissimilar titanium/aluminum alloys has been employed at an increasing rate,particularly in the aerospace industry,owing to its advantages in terms of current design flexibility and fuel/cost *** major problem with dissimilar Ti/Al welds arises from the difference in the thermal expansion and contraction of the two metals,which leads to hot-cracking susceptibility and the mitigation of the mechanical property after *** the present study,pulsed Nd:YAG laser welding of Ti6 Al4 V and AA6060 has been ***-cracking susceptibility in the heat affected zone and the shear fracture behavior of the lap joints were investigated through microstructural characterization and mechanical *** results indicate that the hot cracking tendency can be reduced by increasing the pulse peak power(7.5–8.5 kW)and the laser point diameter(0.8–1.0 mm)with specific pulse duration and *** alternative control strategy for less hot cracks in the Ti/Al lap joint can be to increase the weld width and decrease the cooling rate during *** shear fracture of the Ti/Al lap joint is likely to occur along the lower side path of the weld interface with decreasing weld surface collapsed amount and increasing aluminum base metal melt depth.

关键词： Aluminum alloy Hot-cracking susceptibility Pulsed Nd:YAG laser welding Shear fracture behavior Titanium alloy

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Thermodynamic property of sandwich cylindrical shell structure with metallic wire mesh:Numerical modeling and experimental analysis

引用

Chinese Journal of Aeronautics 2024年第1期37卷 138-152页

作者： Xin XUE Guojian SHEN juan liao Institute of Metal Rubber&Vibration Noise School of Mechanical Engineering and AutomationFuzhou UniversityFuzhou 350116China Fujian Shuikou Power Generation Group Co. LTDFuzhou 350000China

As a new addition to lightweight composite structures,the sandwich cylindrical shell with a metallic wire mesh core has emerged as a promising solution for thermodynamic performance analysis at elevated *** intricate interwoven cellular formations within the metallic wire mesh pose difficulties for thermo-mechanical modeling and property ***,the constitutive models employed to characterize hysteresis phenomena were presented,comprising isotropic elasticity,Bergstrom-Boyce model,Ogden hyper-elasticity,and parameter identification through mechanical examinations at varying ***,the finite element modeling of cylindrical shell structures was determined for modal and steady-state dynamic ***,the experimental procedures were carried out,including the preparation of the sandwich cylindrical shell and the dynamic testing *** first-order natural frequency of the cylindrical shell structure is close to the resonance frequency of the dynamic test results,with a maximum error of 6.5%,demonstrating the accuracy of the simulation *** compared to the solid-core cylindrical shell,the average insertion loss of the sandwich cylindrical shell structure within the frequency range of 10–1000 Hz at room temperature is up to 11.09 ***,at elevated temperatures,the average insertion loss of the sandwich cylindrical shell decreases but fluctuates as the temperature changes.

关键词： Energy dissipation Metallic matrix composites Numerical analysis Sandwich structure Thermodynamic properties

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Interface property of dissimilar Ti-6Al-4V/AA1050 composite laminate made by non-equal channel lateral co-extrusion and heat treatment

引用

Defence Technology（防务技术） 2024年第3期33卷 197-208页

作者： juan liao Mengmeng Tian Xin Xue School of Mechanical Engineering and Automation Fuzhou UniversityFuzhou 350116China

The purpose of this paper is to examine the effect of processing parameters and subsequent heat treatments on the microstructures and bonding strengths of Ti-6Al-4V/AA1050 laminations formed via a non-equal channel lateral co-extrusion *** microstructural evolution and growth mechanism in the diffusion layer were discussed further to optimize the bonding quality by appropriately adjusting process *** electron microscopes(SEM),energy dispersive spectrometer(EDS),and X-ray diffraction(XRD)were used to characterize interfacial diffusion *** shear test was used to determine the mechanical properties of the interfacial diffusion *** experimental results indicate that it is possible to co-extrusion Ti-6Al-4V/AA1050 compound profiles using non-equal channel lateral *** heat treatment processes affect the thickness of the diffusion *** the temperature and time of heat treatment increase,the thickness of the reaction layers increases ***,the shear strength of the Ti-6Al-4V/AA1050 composite interface is proportional to the diffusion layer *** is observed that a medium interface thickness results in superior mechanical performance when compared to neither a greater nor a lesser interface *** characterization of all heat treatments reveals that the only intermetallic compound observed in the diffusion layers is TiAl_(3).Due to the inter-diffusion of Ti and Al atoms,the TiAl_(3) layer grows primarily at AA1050/TiAl_(3) interfaces.

关键词： Shear strength Co-extrusion Heat treatment Microstructure Intermetallic compounds

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A consistent projection-based SUPG/PSPG XFEM for incompressible two-phase flows

引用

Acta Mechanica Sinica 2012年第5期28卷 1309-1322页

作者： Jian-hui liao Zhuo Zhuang School of Aerospace Tsinghua University

In this paper, a consistent projection-based streamline upwind/pressure stabilizing Petrov-Galerkin （SUPG/PSPG） extended finite element method （XFEM） is presented to model incompressible immiscible two-phase flows. As the application of linear elements in SUPG/PSPG schemes gives rise to inconsistency in stabilization terms due to the inability to regenerate the diffusive term from viscous stresses, the numerical accuracy would deteriorate dramatically. To address this issue, projections of convection and pressure gradient terms are constructed and incorporated into the stabilization formulation in our method. This would substantially recover the consistency and free the practitioner from burdensome computations of most items in the residual. Moreover, the XFEM is employed to consider in a convenient way the fluid properties that have interfacial jumps leading to discontinuities in the velocity and pressure fields as well as the projections. A number of numerical examples are analyzed to demonstrate the complete recovery of consistency, the reproduction of interfacial discontinuities and the ability of the proposed projection-based SUPG/PSPG XFEM to model two-phase flows with open and closed interfaces.

关键词： Two-phase flow XFEM SUPG/PSPG algorithm Consistency Discontinuous projection

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：