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肿瘤表观基因型在临床中的应用
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作者 樊红 《世界华人消化杂志》 CAS 北大核心 2006年第20期1951-1955,共5页
肿瘤不仅是遗传性疾病,同时也是由基因转录沉默所引起的表观遗传学性疾病.表观遗传学(epigenetics)是研究不涉及DNA序列变化的、可遗传的基因表达调控方式的一门科学.肿瘤中表观遗传学的改变包括影响基因差异表达的DNA甲基化、组蛋白乙... 肿瘤不仅是遗传性疾病,同时也是由基因转录沉默所引起的表观遗传学性疾病.表观遗传学(epigenetics)是研究不涉及DNA序列变化的、可遗传的基因表达调控方式的一门科学.肿瘤中表观遗传学的改变包括影响基因差异表达的DNA甲基化、组蛋白乙酰化/组蛋白去乙酰化和染色质重塑等几个方面,表观基因型(epigenotype)是描述有共同基因型的不同类型细胞的基因表达模式和基因失活模式,表观遗传学机制决定了表观基因型的形成.肿瘤表观遗传学机制贯穿肿瘤发生、发展的整个过程,并具有一定的广泛性和组织特异性,因此认识肿瘤中表观基因型将对肿瘤的临床诊断、治疗和预防有着重要的指导意义. 展开更多
关键词 表观遗传学 表观基因 DNA甲基化 染色质重塑 肿瘤
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氧化剂协同即时成膜型光催化反应器降解有机物 被引量:1
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作者 魏宏斌 侯娜 +2 位作者 陈良才 王志海 杨庆娟 《中国给水排水》 CAS CSCD 北大核心 2008年第21期34-37,共4页
研究了"表观"即时成膜型UV/TiO2光催化反应器降解水中有机污染物的过程中,外加氧化剂与UV/TiO2体系之间的协同效应。在UV/TiO2体系中单独投加H2O2或O3可以提高光催化氧化有机污染物的速率和效率,同时投加H2O2和O3时则光催化... 研究了"表观"即时成膜型UV/TiO2光催化反应器降解水中有机污染物的过程中,外加氧化剂与UV/TiO2体系之间的协同效应。在UV/TiO2体系中单独投加H2O2或O3可以提高光催化氧化有机污染物的速率和效率,同时投加H2O2和O3时则光催化氧化的协同作用更加显著,可大大缩短反应时间。不同反应体系的表观速率常数排序为:UV/H2O2/O3/TiO2>UV/O3/TiO2>UV/H2O2/TiO2>UV/O3>UV/H2O2>UV/TiO2。 展开更多
关键词 表观”即时成膜光催化反应器 光催化氧化 氧化剂 协同效应
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A new electromagnetic functional material composed of metallic hollow micro-spheres 被引量:4
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作者 徐鸿飞 徐丽娜 +1 位作者 顾宁 孙忠良 《Journal of Southeast University(English Edition)》 EI CAS 2003年第1期8-11,共4页
This paper presents a new electromagnetic functional material developed byelectron-less nickel deposition technique, with a single hollow micro-sphere as the core templateand a thin nickel layer as the shell. The micr... This paper presents a new electromagnetic functional material developed byelectron-less nickel deposition technique, with a single hollow micro-sphere as the core templateand a thin nickel layer as the shell. The micrograph taken by a scanning electron microscope showsthe microstructures of the materials in detail. Scattering parameters of the waveguide sample holderfilled with the materials have been obtained over X band. The electromagnetic parameters computedfrom the measured S parameters show that the material with metallic hollow spheres has as highrelative permeability μ'_r as 19.0 with about 0.6 magnetic loss tangent over the whole bandwidth.Compared to the material with non-metallic spheres, the permeability μ'_r and the magnetic losstangent μ'_r increase greatly, while the permittivity remains lower than 1.8. 展开更多
关键词 electromagnetic functional material microwave absorbing electron-lessdeposition
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寻找“过失”行为的闪光点——中学生某些个性心理特征浅析
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作者 扶深永 《教育实践与研究》 2002年第6期7-8,共2页
中学生的某些'过失'行为往往隐藏着一些闪光点,教师要仔细分析,加以正确引导以促进其心理健康发展.
关键词 中学生 过失行为 个性心理 特征 表观型 逆反 批评教育
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黑素瘤分子分型研究现状
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作者 吴曹英 康晓静 《中国皮肤性病学杂志》 CAS CSCD 北大核心 2024年第5期482-487,共6页
黑素瘤是皮肤肿瘤中恶性程度最高的肿瘤,随着精准医学时代的来临,靶向治疗、免疫治疗取得突破性进展。随着高通量测序技术的出现,黑素瘤的基因组、转录组、表观遗传组、蛋白质组景观逐渐被揭晓。基于高通量数据的分子分型不仅能揭示黑... 黑素瘤是皮肤肿瘤中恶性程度最高的肿瘤,随着精准医学时代的来临,靶向治疗、免疫治疗取得突破性进展。随着高通量测序技术的出现,黑素瘤的基因组、转录组、表观遗传组、蛋白质组景观逐渐被揭晓。基于高通量数据的分子分型不仅能揭示黑素瘤的异质性,还能很好地辅助黑素瘤临床分型、指导药物选择、预测预后、预测免疫治疗反应及药物开发等。本文对黑素瘤分子分型进展进行阐述,为个体化和精准诊治提供指导。 展开更多
关键词 黑素瘤分子分 基因组分 表观遗传组分 转录组分 蛋白质组分
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Technological conditions and kinetics of leaching copper from complex copper oxide ore 被引量:10
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作者 孙锡良 陈白珍 +1 位作者 杨喜云 刘有源 《Journal of Central South University》 SCIE EI CAS 2009年第6期936-941,共6页
The kinetic behavior of leaching copper from low grade copper oxide ore was investigated. The effects of leaching temperature, H2SO4 concentration, particle size of crude ore and agitation rate on the leaching efficie... The kinetic behavior of leaching copper from low grade copper oxide ore was investigated. The effects of leaching temperature, H2SO4 concentration, particle size of crude ore and agitation rate on the leaching efficiency of copper were also evaluated. And the kinetic equations of the leaching process were obtained. The results show that the leaching process can be described with a reaction model of shrinking core. The reaction can be divided into three stages. The first stage is the dissolution of free copper oxide and copper oxide wrapped by hematite-limonite ore. At this stage, the leaching efficiency is very fast (leaching efficiency is larger than 60%). The second stage is the leaching of diffiuent copper oxides, whose apparent activation energy is 43.26 kJ/mol. During this process, the chemical reaction is the control step, and the reaction order of H2SO4 is 0.433 84. The third stage is the leaching of copper oxide wrapped by hematite-limonite and silicate ore with apparent activation energy of 16.08 kJ/mol, which belongs to the mixed control. 展开更多
关键词 copper oxide ore H2SO4 LEACHING KINETICS activation energy
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Russel Silver综合征19例病例系列报告
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作者 张萍 刘仁超 +3 位作者 陆炜 吴冰冰 王慧君 周文浩 《中国循证儿科杂志》 CSCD 北大核心 2019年第4期282-286,共5页
目的总结分析经甲基化特异性多重链接探针扩增技术(MS-MLPA)确诊的Russel Silver综合征(RSS)患儿的临床特征、基因型(表观突变)以及表型和基因型的相关性,旨在提升对该病的认识。方法收集2015年1月1日至2019年6月30日复旦大学附属儿科医... 目的总结分析经甲基化特异性多重链接探针扩增技术(MS-MLPA)确诊的Russel Silver综合征(RSS)患儿的临床特征、基因型(表观突变)以及表型和基因型的相关性,旨在提升对该病的认识。方法收集2015年1月1日至2019年6月30日复旦大学附属儿科医院(我院)分子医学中心经MS-MLPA确诊的RSS连续病例的临床资料。MS-MLPA行11p15区域甲基化和拷贝数变异(CNV)情况检测,应用Gene Marker软件对实验数据进行均一化处理及结果判读。结果19例RSS患儿,女8例,男11例,确诊年龄中位数3.3岁(3月龄至10岁)。小于胎龄儿18例,就诊时18例患儿身高均低于同龄儿童身高P3,体重均低于同龄儿童体重P10。特殊面容发生率较高的表型有前额突出9例,三角脸7例,肢体不对称和手指短或内侧弯曲6例,小下颌5例。其他表现包括眼距宽、低耳位、高腭弓、牙齿突出、胸廓畸形、脊柱侧凸和房间隔缺损等。19例RSS患儿有3例检测到携带11p15区域拷贝数重复,余16例均显示H19-DMR低甲基化且无CNV。结论有宫内和出生后生长发育迟缓、肢体不对称和特殊面容的儿童,应注意RSS的可能,首选MS-MLPA检测,以利于及早干预和遗传咨询。 展开更多
关键词 Russel Silver综合征 甲基化特异性多重链接探针扩增技术 临床特征 基因(表观突变)
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Pathological and MR-DWI study of the acute hepatic injury model after stem cell transplantation 被引量:6
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作者 Quan-Liang Shang En-Hua Xiao +2 位作者 Qi-Chang Zhou Jian-Guang Luo Hai-Jun Wu 《World Journal of Gastroenterology》 SCIE CAS CSCD 2011年第23期2821-2828,共8页
AIM: To investigate apparent diffusion coefficient (ADC) values as an indication of reconditioning of acute hepatic injury (AHI) after allogeneic mononuclear bone marrow cell (MBMC) transplantation. METHODS: T... AIM: To investigate apparent diffusion coefficient (ADC) values as an indication of reconditioning of acute hepatic injury (AHI) after allogeneic mononuclear bone marrow cell (MBMC) transplantation. METHODS: Three groups were used in our study: a cell transplantation group (n = 21), transplantation control group (n = 21) and normal control group (n = 10). AHI model rabbits in the cell transplantation group were injected with 5 mL of MBMC suspension at multiple sites in the liver and the transplantation controls were injected with 5 mL D-Hanks solution. At the end of the 1st, 2nd and 4th wk, 7 rabbits were randomly selected from the cell transplantation group and trans- plantation control group for magnetic resonance diffu- sion-weighted imaging (MR-DWI) and measurement of the mean ADC values of injured livers. After MR-DWI examination, the rabbits were sacrificed and the livers subjected to pathological examination. Ten healthy rab- bits from the normal control group were used for MR- DWI examination and measurement of the mean ADC value of normal liver. RESULTS: At all time points, the liver pathological scores from the cell transplantation group were significantly lower than those in the transplantation control group (27.14± 1.46 vs 69.29± 6.16, 22.29 ± 2.29 vs 57.00± 1.53, 19.00 ± 2.31 vs 51.86 ± 6.04, P = 0.000). The mean ADC values of the cell transplantation group were significantly higher than the transplantation con- trol group ((1.07± 0.07) ×10^-3 mm2/s vs (0.69 ± 0.05) ×10^-3 mm2/s, (1.41± 0.04) ×10^-3 mm2/s vs (0.84± 0.03) ×10^-3 mm2/s, (1.68 ± 0.04) ×10^-3 mm2/s vs (0.86± 0.04) ×10^-3 mm2/s, P = 0.000). The pathological scores of the cell transplantation group and transplantation control group gradually decreased. However, their mean ADC values gradually increased to near that of the normal control. At the end of the 1st wk, the mean ADC values of the cell transplantation group and transplantation control group were significantly lower than those of the normal control group [(1.07 ± 0.07) ×10^-3 mm2/s vs (± 0.03) ×10^-3 mm2/s, (0.69± 0.05) ×10^-3 mm2/s vs (1.76 ± 0.03) ×10^-3 mm2/s, P = 0.000]. At any 2 time points, the pathological scores and the mean ADC values of the cell transplantation group were significantly different (P = 0.000). At the end of the 1st wk, the pathological scores and the mean ADC values of the transplantation control group were significantly different from those at the end of the 2nd and 4th wk (P = 0.000). However, there was no significant difference between the 2nd and 4th wk (P = 0.073 and 0.473, respectively). The coefficient of correlation between the pathological score and the mean ADC value in the cell transplantation group was -0.883 (P = 0.000) and -0.762 (P = 0.000) in the transplantation control group. CONCLUSION: Tracking the longitudinally dynamic change in the mean ADC value of the AHI liver may reflect hepatic injury reconditioning after allogeneic MBMC transplantation. 展开更多
关键词 Stem cells TRANSPLANTATION Hepatic injury Magnetic resonance imaging Diffusion weighted imaging
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Which is better for presenting your data: table or graph? 被引量:1
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作者 张莉 傅小兰 《Journal of Zhejiang University Science》 EI CSCD 2004年第9期1165-1168,共4页
This study aimed at investigating the characteristics of table and graph that people perceive and the data types which people consider the two displays are most appropriate for. Participants in this survey were 195 te... This study aimed at investigating the characteristics of table and graph that people perceive and the data types which people consider the two displays are most appropriate for. Participants in this survey were 195 teachers and undergraduates from four universities in Beijing. The results showed people's different attitudes towards the two forms of display. 展开更多
关键词 TABLE GRAPH Data types Subjective evaluation
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Fluoride Removal by Lanthanum Alginate Bead: Adsorbent Characterization and Adsorption Mechanism 被引量:2
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作者 霍亚坤 丁文明 +2 位作者 黄霞 徐静年 赵梦华 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2011年第3期365-370,共6页
Lanthanum alginate bead is a new, highly active adsorbent. In the present study, we investigated its ad- sorption performance and its adsorption mechanism. The adsorption isotherm for fluoride onto lanthanum alginate ... Lanthanum alginate bead is a new, highly active adsorbent. In the present study, we investigated its ad- sorption performance and its adsorption mechanism. The adsorption isotherm for fluoride onto lanthanum alginate b ead fits the Langmuir model well, and the maximum adsorption capacity is 197.2 mg·g-1. X-ray diffraction shows the amorphous nature of lanthanum alginate bead, which allows for better accessibility to fluoride and thus better activity. Infrared spectra of lanthanum alginate bead before and after adsorption confirm its stable skeletal structure. Scanning electron microscopy shows that the dense surface structure of the adsorbent appear cracks after adsorption. T he adsorption mechanism of lanthanum alginate bead is considered as an ion exchange between F- and Cl- or OH-, as verified from the adsorbent and the solution by pH effect, energy dispersive X-ray, and ion chromatography. 展开更多
关键词 lanthanum alginate fluoride removal adsorbent characterization adsorption mechanism ion exchange
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CFD Simulation of Film Flow and Gas/Liquid Countercurrent Flow on Structured Packing 被引量:8
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作者 高国华 张吕鸿 +1 位作者 李鑫钢 隋红 《Transactions of Tianjin University》 EI CAS 2011年第3期194-198,共5页
A mathematic model of two-phase flow and a physical model of two-dimensional (2D) vertical section for the plate-type structured packing Mellapak 250.Y were set up and verified. The models were used to study the influ... A mathematic model of two-phase flow and a physical model of two-dimensional (2D) vertical section for the plate-type structured packing Mellapak 250.Y were set up and verified. The models were used to study the influence of packing’s surface microstructure on the continuity of liquid film and the amount of liquid holdup. Simulation results show that the round corner shape and micro wavy structure are favorable in remaining the continuity of liquid film and increasing the amount of liquid holdup. The appropriate liquid flow rate was determined by investigating different liquid loadings to obtain an unbroken liquid film on the packing surface. The pressure difference between inlet and outlet for gas phase allowed gas and liquid to flow countercurrently in a 2D computational domain. The direction change of gas flow occurred near the phase interface area. 展开更多
关键词 two-dimension computational fluid dynamics (CFD) film distribution countercurrent flow
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Performance of Regional Integrated Environment Modeling System (RIEMS) in the Simulation of Surface Air Temperature over East Asia 被引量:4
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作者 Zhao De-Ming 《Atmospheric and Oceanic Science Letters》 2012年第2期145-150,共6页
Regional climate models (RCMs) have the potential for more detailed surface characteristic and mesoscale modeling results than general circulation models (GCMs).These advantages have drawn significant focus on RCM dev... Regional climate models (RCMs) have the potential for more detailed surface characteristic and mesoscale modeling results than general circulation models (GCMs).These advantages have drawn significant focus on RCM development in East Asia.The Regional Integrated Environment Modeling System,version 2.0 (RIEMS2.0),has been developed from an earlier RCM,RIEMS1.0,by the Key Laboratory of Regional ClimateEnvironment for Temperate East Asia (RCE-TEA) and Nanjing University.A numerical experiment covering 1979 to 2008 (simulation duration from 1 January 1978 to 31 December 2008) with a 50-km spatial resolution was performed to test the ability of RIEMS2.0 to simulate long-term climate and climate changes in East Asia and to provide a basis for further development and applications.The simulated surface air temperature (SAT) was compared with observed meteorological data.The results show that RIEMS2.0 simulation reproduced the SAT spatial distribution in East Asia but that it was underestimated.The simulated 30-year averaged SAT was approximately 2.0°C lower than the observed SAT.The annual and interannual variations in the averaged SAT and their anomalies were both well reproduced in the model.A further analysis of three sub-regions representing different longitudinal ranges showed that there is a good correlation and consistency between the simulated results and the observed data.The annual variations,interannual variations for the averaged SAT,and the anomalies in the three sub-regions were also captured well by the model.In summary,RIEMS2.0 shows stability and does well both in simulating the long-term SAT in East Asia and in expressing sub-regional characteristics. 展开更多
关键词 RIEMS2.0 surface air temperature CLIMATE simulation ability
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Feeder Type Affects Growth in Weanling Horses
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作者 Carol Jean Thompson Kevin Halden Kline 《Journal of Agricultural Science and Technology(A)》 2015年第7期616-620,共5页
In the interest of decreasing feed costs while maximizing the growth of weanling horses, this study examined the potential difference in the average daily gain (ADG), gain to feed ratio (G/F), and apparent dry mat... In the interest of decreasing feed costs while maximizing the growth of weanling horses, this study examined the potential difference in the average daily gain (ADG), gain to feed ratio (G/F), and apparent dry matter and crude protein digestibility in horses fed with the same diet provided in different feeder types. Sixteen weanling standardbred horses were used for the duration of the 9-week study. The horses were given 2.5% of their body weight in hay and grain daily, 2% hay and 0.5% grain, as fed in two equal feedings at 7:00 am and 7:00 pm. The first treatment used a combined hay and grain feeder with the hay rack positioned over a manger compartment. The second treatment provided hay in an open hay rack and grain in a separate, open-topped feed tub, not positioned under the hay rack. The two groups, with eight horses--four female and four male in each group, were fed in one manner or the other for the length of the study. The weanlings fed in the combined hay and grain feeder had a greater ADG (0.52 kg/d vs. 0.41 kg/d) and G/F (0.06 vs. 0.05) than the horses with the separate hay and grain feeders. Both ADG and G/F means between treatments were statistically different (P 〈 0.05). There was not a significant difference (P 〉 0.05) in the apparent digestibility of dry matter or crude protein between the two groups. Therefore, it was concluded that the combined feeding system resulted in greater growth and apparent G/F most likely due to decreased feed wastage; however, apparent digestibility was not different between feeding systems. 展开更多
关键词 HORSE GROWTH DIGESTIBILITY feeder.
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Modeling bidirectional reflection distribution function of microscale random rough surfaces
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作者 王爱华 HSU P.F. 蔡九菊 《Journal of Central South University》 SCIE EI CAS 2010年第2期228-234,共7页
The radiative properties of three different materials surfaces with one-dimensional microscale random roughness were obtained with the finite difference time domain method(FDTD) and near-to-far-field transformation.Th... The radiative properties of three different materials surfaces with one-dimensional microscale random roughness were obtained with the finite difference time domain method(FDTD) and near-to-far-field transformation.The surface height conforms to the Gaussian probability density function distribution.Various computational modeling issues that affect the accuracy of the predicted properties were discussed.The results show that,for perfect electric conductor(PEC) surfaces,as the surface roughness increases,the magnitude of the spike reduces and eventually the spike disappears,and also as the ratio of root mean square roughness to the surface correlation distance increases,the retroreflection becomes evident.The predicted values of FDTD solutions are in good agreement with the ray tracing and integral equation solutions.The overall trend of bidirectional reflection distribution function(BRDF) of PEC surfaces and silicon surfaces is the same,but the silicon's is much less than the former's.The BRDF difference from two polarization modes for the gold surfaces is little for smaller wavelength,but it is much larger for the longer wavelength and the FDTD simulation results agree well with the measured data.In terms of PEC surfaces,as the incident angle increases,the reflectivity becomes more specular. 展开更多
关键词 bidirectional reflection distribution fimction random rough surfaces Maxwell equations finite difference time domain method
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How might epigenetics contribute to ecological speciation? 被引量:1
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作者 Gilbert SMITH Michael G. RITCHIE 《Current Zoology》 SCIE CAS CSCD 2013年第5期686-696,共11页
Speciation research has seen a renewed interest in ecological speciation, which emphasises divergent ecological se- lection leading to the evolution of reproductive isolation. Selection from divergent ecologies means ... Speciation research has seen a renewed interest in ecological speciation, which emphasises divergent ecological se- lection leading to the evolution of reproductive isolation. Selection from divergent ecologies means that phenotypic plasticity can play an important role in ecological speciation. Phenotypic plasticity involves the induction of phenotypes over the lifetime of an organism and emerging evidence suggests that epigenetic marks such as cytosine and protein (histone) modifications might regu- late such environmental induction. Epigenetic marks play a wide role in a variety of processes including development, sex dif- ferentiation and allocation, sexual conflict, regulation of transposable elements and phenotypic plasticity. Here we describe recent studies that investigate epigenetic mechanisms in a variety of contexts. There is mounting evidence for environmentally induced epigenetic variation and for the stable inheritance of epigenetic marks between generations. Thus, epigenetically-based pheno- typic plasticity may play a role in adaptation and ecological speciation. However, there is less evidence for the inheritance of in- duced epigenetic variation across multiple generations in animals. Currently few studies of ecological speciation incorporate the potential for the involvement of epigenetically-based induction of phenotypes, and we argue that this is an important omission [Current Zoology 59 (5): 686-696, 2013 ]. 展开更多
关键词 Ecological speciation ADAPTATION Reproductive isolation Phenotypic plasticity Epigenetic mechanisms
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Autism spectrum disorder model mice: Focus on copy number variation and epigenetics 被引量:4
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作者 Nobuhiro NAKAI Susumu OTSUKA +1 位作者 Jihwan MYUNG Toru TAKUMI 《Science China(Life Sciences)》 SCIE CAS CSCD 2015年第10期976-984,共9页
Autism spectrum disorder(ASD) is gathering concerns in socially developed countries. ASD is a neuropsychiatric disorder of genetic origin with high prevalence of 1%–2%. The patients with ASD characteristically show i... Autism spectrum disorder(ASD) is gathering concerns in socially developed countries. ASD is a neuropsychiatric disorder of genetic origin with high prevalence of 1%–2%. The patients with ASD characteristically show impaired social skills. Today, many genetic studies identify numerous susceptible genes and genetic loci associated with ASD. Although some genetic factors can lead to abnormal brain function linked to ASD phenotypes, the pathogenic mechanism of ASD is still unclear. Here, we discuss a new mouse model for ASD as an advanced tool to understand the mechanism of ASD. 展开更多
关键词 copy number variations DNA methylation histone modification ASD model mouse
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Natal dispersal in a social landscape: Considering individual behavioral phenotypes and social environment in dispersal ecology 被引量:2
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作者 Tina W. WEY Orr SPIEGEL +1 位作者 Pierre-Olivier MONTIGLIO Karen E. MABRY 《Current Zoology》 SCIE CAS CSCD 2015年第3期543-556,共14页
Natal dispersal, the movement of an organism from its birthplace to the site of first reproduction, is fundamental to many ecological and evolutionary processes. Mechanistically, individual dispersal decisions can dep... Natal dispersal, the movement of an organism from its birthplace to the site of first reproduction, is fundamental to many ecological and evolutionary processes. Mechanistically, individual dispersal decisions can depend on both individual phe- notype and environmental cues. In particular, many established evolutionary theories of dispersal highlight the importance of the social environment. More recent research in behavioral ecology has focused on the importance of individual behavioral pheno- types. We reviewed the literature on individual behavioral phenotypes and dispersal and suggest that how individual behavioral phenotypes interact with the immediate social environment experienced by individuals in influencing dispersal is still poorly un- derstood, despite growing interest. We found that very few studies had examined the interaction of individual behavioral pheno- types and social factors, and behavioral phenotypes related to social tendencies were less commonly measured than were beha- vioral phenotypes related to exploration or response to risk. Further, and unsurprisingly, studies on social behavioral phenotypes and dispersal behaviors during the transience stage of dispersal were underrepresented compared to the departure or settlement stages. Future studies in this area should aim to" a) make explicit links between behavioral traits and their proposed effects on dispersal decisions throughout multiple stages of dispersal, b) integrate more continuous dispersal variables, and c) consider the effects of the spatial distribution and phenotypes of conspecifics (i.e., the social landscape) encountered by individual dispersers 展开更多
关键词 Animal dispersal Animal personality Behavioral syndromes Individual differences Social landscape
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Visible characteristics of space-based targets based on bidirectional reflection distribution function 被引量:3
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作者 WANG HongYuan ZHANG Wei WANG FuGang 《Science China(Technological Sciences)》 SCIE EI CAS 2012年第4期982-989,共8页
A precise modeling method of visible characteristics of the space-based target was presented based on bidirectional reflection distribution function (BRDF). The background characteristics of the space-based target wer... A precise modeling method of visible characteristics of the space-based target was presented based on bidirectional reflection distribution function (BRDF). The background characteristics of the space-based target were represented to build models of direct solar radiation and reflected radiation of the Earth based on blackbody radiation theory. The geometry characteristics of the target were analyzed to establish a surface equation of each surface based on its body coordinate system. The material characteristics of the target surface were described by introducing a BRDF model which considers the character of surface Gauss statistics and self-shadow and is obtained by measurement and modeling in advance. The relative positions of the space-based target, the background radiation sources and the observation platform were determined based on coordinate con- version to judge contributing surface of the target to observation system. Then a mathematical model on visible characteristics of the space target for the given optical system was built by summing reflection components of all the surfaces. Simulation of visible characteristics of the space-based target in orbit was achieved according to its given geometrical dimensions, physical parameters and orbital parameters. The results show that the method is effective for analysis on visible characteristics of the space-based target when single reflection is considered and its surface is regularly described in a surface equation, which provides a way to real-time calculation of visible characteristics of the space-based target. 展开更多
关键词 space optics space-based target visible characteristics bidirectional reflection distribution function (BRDF)
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The blood-brain barrier permeability of 20(S) and 20(R)-protopanaxatriol epimers and dammar-20(22)E,24-diene-3β,6α,12β-triol in MDCK-pHa MDR cell monolayer model 被引量:1
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作者 郑怡然 吴秀稳 杨秀伟 《Journal of Chinese Pharmaceutical Sciences》 CAS CSCD 2017年第8期566-573,共8页
The blood-brain barrier permeability of 20(S) and 20(R)-protopanaxatriol epimers and dammar-20(22)E,24-diene- 313,6α,12β-triol were investigated using the MDCK-pHaMDR cell monolayer model. The bidirectional pe... The blood-brain barrier permeability of 20(S) and 20(R)-protopanaxatriol epimers and dammar-20(22)E,24-diene- 313,6α,12β-triol were investigated using the MDCK-pHaMDR cell monolayer model. The bidirectional permeability tests were carried out, and the apparent permeability coefficients (Papp) were calculated. The two protopanaxatriol epimers showed good permeability with Papp values of-10^-5 cm/s, whereas dammar-20(22)E,24-diene-3β,6α, 12β-triol showed poor permeability with Papp of 〈1 × 10^-7 cm/s. The three compounds showed differences in intracellular accumulations due to their different structures. Inhibition of P-gp with verapamil showed that the transport mechanisms in MDCK-pHaMDR cell monolayer for compounds 1 and 2 epimers were not only simple passive diffusion but also involving an effiux way mediated by P-gp. These findings provided new basis for the further study of compounds 1 and 2 acting on the brain. 展开更多
关键词 20(S)-Protopanaxatriol 20(R)-Protopanaxatriol Dammar-20(22)E 24-diene-3β 12β-triol MDCK-pHaMDR Permeability Blood-brain barrier
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Thermodynamics of the Apparent Horizon in FRW Universe with Massive Gravity 被引量:1
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作者 李辉 张益 《Communications in Theoretical Physics》 SCIE CAS CSCD 2013年第7期28-36,共9页
Applying Clausius relation with energy-supply defined by the unified first law of thermodynamics formalism to the apparent horizon of a massive gravity model in cosmology proposed lately, the corrected entropic formul... Applying Clausius relation with energy-supply defined by the unified first law of thermodynamics formalism to the apparent horizon of a massive gravity model in cosmology proposed lately, the corrected entropic formula of the apparent horizon is obtaJned with the help of the modified Friedmann equations. This entropy-area relation, together with the identified Misner-Sharp internal energy, verifies the first law of thermodynamics for the apparent horizon with a volume change term for consistency. On the other hand, by means of the corrected entropy-area formula and the Clausius relation δQ = T dS, where the heat flow δQ is the energy-supply of pure matter projecting on the vector ξ tangent to the apparent horizon and should be looked on as the amount of energy crossing the apparent horizon during the time interval dt and the temperature of the apparent horizon for energy crossing during the same interval is 1/(2πτA), the modified Friedmann equations governing the dynamical evolution of the universe are reproduced with the known energy density and pressure of massive graviton. The integration constant is found to correspond to a cosmological term which could be absorbed into the energy density of matter. Having established the correspondence of massive cosmology with the unified first law of thermodynamics on the apparent horizon, the validity of the generalized second law of thermodynamics is also discussed by assuming the thermal equilibrium between the apparent horizon and the matter field bounded by the apparent horizon. It is found that, in the limit Hc → 0, which recovers the Minkowski reference metric solution in the fiat case, the generalized second law of thermodynamics holds if α3 + 4α4 〈 0. Without this condition, even for the simplest model of dRGT massive cosmology with α3= α4 = 0, the generalized second law of thermodynamics could be violated. 展开更多
关键词 unified first law of thermodynamics Clausius relation dRGT massive gravity generalized secondlaw of thermodynamics
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