期刊文献+
共找到1,863篇文章
< 1 2 94 >
每页显示 20 50 100
Gene Expression Data Analysis Based on Mixed Effects Model
1
作者 Yuanbo Dai 《Journal of Computer and Communications》 2025年第2期223-235,共13页
DNA microarray technology is an extremely effective technique for studying gene expression patterns in cells, and the main challenge currently faced by this technology is how to analyze the large amount of gene expres... DNA microarray technology is an extremely effective technique for studying gene expression patterns in cells, and the main challenge currently faced by this technology is how to analyze the large amount of gene expression data generated. To address this, this paper employs a mixed-effects model to analyze gene expression data. In terms of data selection, 1176 genes from the white mouse gene expression dataset under two experimental conditions were chosen, setting up two conditions: pneumococcal infection and no infection, and constructing a mixed-effects model. After preprocessing the gene chip information, the data were imported into the model, preliminary results were calculated, and permutation tests were performed to biologically validate the preliminary results using GSEA. The final dataset consists of 20 groups of gene expression data from pneumococcal infection, which categorizes functionally related genes based on the similarity of their expression profiles, facilitating the study of genes with unknown functions. 展开更多
关键词 Mixed Effects model Gene expression Data Analysis Gene Analysis Gene Chip
暂未订购
Expression,purification and molecular modeling of iron-containing superoxide dismutase from Acidithiobacillus ferrooxidans 被引量:1
2
作者 刘元东 高建 +5 位作者 邱冠周 刘学端 张成桂 欧阳叙东 蒋莹 曾佳 《中国有色金属学会会刊:英文版》 EI CSCD 2008年第6期1361-1366,共6页
从 Acidithiobacillus ferrooxidans 的 superoxide dismutase (草皮) 可以在它的忍耐起一个重要作用到 bioleaching 的极其有毒、氧化的环境。这基因在 Escherichia 被克隆然后成功地表示了 coli。表示蛋白质被一步舞亲密关系层析最后... 从 Acidithiobacillus ferrooxidans 的 superoxide dismutase (草皮) 可以在它的忍耐起一个重要作用到 bioleaching 的极其有毒、氧化的环境。这基因在 Escherichia 被克隆然后成功地表示了 coli。表示蛋白质被一步舞亲密关系层析最后净化到同质并且观察了根据 SDS 页和 MALDI-TOF-MS 更暗淡。金属内容决心和 recombinant 蛋白质的光系列结果证实蛋白质是包含铁的 superoxide dismutase。为蛋白质的分子的建模表明铁原子被 His26, His75, Asp158 和 His162 绑扎。 展开更多
关键词 超氧歧化酶 基因表达 纯化 分子模型
在线阅读 下载PDF
Expression model for multiple relationships in the ontology of traditional Chinese medicine knowledge
3
作者 Mingyue Gao Lepeng Wang Meng Cui 《Journal of Traditional Chinese Medical Sciences》 2016年第1期59-65,共7页
Objective:To explore multiple relationships in traditional Chinese medicine(TCM)knowledge by comparing binary and multiple relationships during knowledge organization.Methods:Characteristics of binary and multiple sem... Objective:To explore multiple relationships in traditional Chinese medicine(TCM)knowledge by comparing binary and multiple relationships during knowledge organization.Methods:Characteristics of binary and multiple semantic relationships as well as their associations are described.A method to classify multiple relationships based on the involvement of time is proposed and theoretically validated using examples from the ancient TCM classic Important Formulas Worth a Thousand Gold Pieces.The classification includes parallel multiple relationships,restricted multiple relationships,multiple relationships that involve time,and multiple relationships that involve time restriction.Next,construction of multiple semantic relationships for TCM concepts in each classification using Protege,an ontology editing tool is described.Results:Protege is superior to a binary relationship and less than ideal with multiple relationships during the constitution of concept relationships.Conclusion:When applied in TCM,the semantic relationships constructed by Protege are superior than those constructed by correlation and/or attribute relationships,but less ideal than those constructed by the human cognitive process. 展开更多
关键词 Multiple relationships ONTOLOGY expression model In traditional Chinese medicine knowledge
暂未订购
Expression Pattern of Testis-specific Expressed Gene 2 in Cryptorchidism Model and Its Role in Apoptosis of Spermatogenic Cells 被引量:2
4
作者 胡涛 王智宇 +4 位作者 曾甫清 陈晓春 顾朝辉 郑丽端 童强松 《Journal of Huazhong University of Science and Technology(Medical Sciences)》 SCIE CAS 2010年第2期193-197,共5页
In our previous study, we identified a novel testis-specific expressed gene 2 (TSEG-2) from mouse testis. To further investigate its functions, 35 male Balb/c mice (8 weeks old) were divided into cryptorchidism gr... In our previous study, we identified a novel testis-specific expressed gene 2 (TSEG-2) from mouse testis. To further investigate its functions, 35 male Balb/c mice (8 weeks old) were divided into cryptorchidism group (n=20), sham group (n=10), and control group (n=5). In cryptorchidism group, the right testes were anchored to the inner lateral abdominal wall. In situ hybridization (ISH) was applied to measure the localization of TSEG-2 in mouse testis. Real-time quantitative PCR was performed to detect the expression of TSEG-2 gene. Meanwhile, under the mediation of polyethylenimine (PEI), the recombinant vector pEGFP-TSEG-2 (n=5) or empty vector (mock, n=5) was transfected into the testis of male mice. The transfection efficiencies were measured under a fluorescence microscope. The apoptosis of spermatogenic cells was detected by terminal deoxynuleotidyl-mediated nick end labeling (TUNEL). The results showed that TSEG-2 was expressed in convoluted seminiferous tubules, more precisely, in spermatogonia and spermatocytes. As compared with sham and control groups, the TSEG-2 transcription was significantly enhanced (P〈0.05) and was correlated with apoptosis of spermatogenic cells in cryptorchid testes (P〈0.05). PEI was efficient in mediating transfeetion of TSEG-2 into seminiferous tubules of testis. One week post-transfection, intratesticular injection of TSEG-2 resulted in increased apoptosis of spermatogenic cells in vivo (P〈0.05). These results indicate that TSEG-2 may participate in the apoptosis of spermatogenic cells and the pathogenesis of cryptorchidism. 展开更多
关键词 animal model testis-specific expressed gene 2 polyethylenimine APOPTOSIS
暂未订购
Expression of calbindin D28K in substantia nigra of model rats with Parkinson disease 被引量:2
5
作者 Dianshuai Gao Hongmei Liu Yanxia Ding Hongjun Wang Yanqiang Wang 《Neural Regeneration Research》 SCIE CAS CSCD 2006年第2期121-125,共5页
BACKGROUND: Previous researches suggested that expression level of calbindin D28K mRNA decreased in substantia nigra (SN) of model rats with Parkinson disease (PD), and this might be related to the decrease of an... BACKGROUND: Previous researches suggested that expression level of calbindin D28K mRNA decreased in substantia nigra (SN) of model rats with Parkinson disease (PD), and this might be related to the decrease of anti-degeneration potentials of dopaminergic neurons. OBJECTIVE: To observe expression changes of calbindin D28K in SN dopaminergic neurons during their degeneration and death in midbrain of PD model rats. DESIGN: Completely randomized grouping design SETTING: Department of Neurobiology, Xuzhou Medical College MATERIALS" A total of 92 healthy male SD rats, with the age of 3 months, weighing 200-250 g, were selected from Experimental Animal Center of Xuzhou Medical College [certification: SCXK (su) 2003-0003]. Calbindin D28K(CB), tyroxine hydroxylase (TH), ABC kit, 6-hydroxydopamine (6-OHDA) and Nissl dyes were provided by Sigma Company, and sheep serum was provided by Beijing Zhongshan Company. METHODS: The experiment was carried out in the Neurobiological Center of Xuzhou Medical College from October 2003 to October 2004. ① With lot method, rats were divided into blank control group (n=28), experimental control group (n=-28) and experimental group (n=36). Rats in experimental group were injected with 6-OHDA at right corpus striatum for PD modeling; rats in experimental control group were injected with saline at the same site; rats in blank control group did not give any injections.② On the 7^th, 14^th, 21^st and 28^th days, SN segments on right midbrain from every 5 rats in experimental group were fixed, embedded with paraffin and cut into successively coronary pieces. Rats in other two groups were treated with the same methods and then stained with Nissl to show neuronal form. Meanwhile, CB and TH antibodies staining with immunohistochemistry were used to show CB containing dopaminergic neurons and dopaminergic neurons, and cells were calculated and observed under optic microscope. ③ On the 14^th and 28^th days, every 4 rats in experimental group and every 4 rats in control group were selected to obtain their brains and separate SN on the injured side. Western blot was used to detect expression of calbindin D28K, protein band was scanned with imaging equipment, and data were analyzed with LabWorks software. MAIN OUTCOME MEASURES:① On the 7^th, 14^th, 21^st and 28^th days, Nissl staining results of SN neurons and immunohistochemical staining results of CB and TH antibodies; ② On the 14^th and 28^th days, Western blot results of calbindin D28K in SN neurons, RESULTS; Among 92 rats, 2 rats in experimental group died after 1 day due to 6-OHDA injection and other 90 rats were involved in the final analysis. ①Nissl staining results: On the 7^th day of 6-OHDA injection, most neuronal somas on right SN pars compacta were shown as deep pycnosis or lysis breakage; on the 14^th and 21^st days, amount of neurons was decreased remarkably; on the 28^th day, most neurons in SN pars compacta disappeared. ② Results of immunohistochemical staining: Amount of positive neurons of calbindin D28K in right SN pars compacta was not changed on the 7^th day after 6-OHDA injection; on the 14^th day, the amount was higher in experimental group than that in both control groups (P 〈 0.01) and was decreased till the 21^st day, but it was still higher than that in the two control groups (P 〈 0.05); on the 28^th day, positive neurons of calbindin D28K nearly disappeared, and the amount was lower than that in the two control groups (P 〈 0.01). In addition, on the 7^th day after 6-OHDA injection into corpus striatum, positive TH neurons decreased 24% in right SN, and there was significant difference from that in control groups; on the 14^th, 21^st and 28^th days, positive TH neurons decreased 37%, 46% and 64%, respectively. ③ Western blot results: On the 14'h day after 6-OHDA injection into corpus striatum, expression of calbindin D28K in right SN was higher in experimental group than that in both control groups (P 〈 0.05); however, on the 28^th day, the expression was lower than that in the two control groups (P 〈 0.01 ). CONCLUSION : During degeneration and death of dopaminergic neurons, CB expression in SN pars compacta increases firstly and decreased gradually. 展开更多
关键词 FIGURE expression of calbindin D28K in substantia nigra of model rats with Parkinson disease
暂未订购
Interventional effect of hirudin on the expression of microtubule-associated protein 2 in peripheral tissue of hematom of model rats with acute intracerebral hemorrhage 被引量:2
6
作者 Jiachun Feng Ying Zhang Fang Deng 《Neural Regeneration Research》 SCIE CAS CSCD 2006年第3期230-233,共4页
BACKGROUND: It is suspected that dissociation, destruction or synthetic disorder of microtubule-associated protein 2 (MAP-2) may participate in secondary injury of intracerebral hemorrhage (ICH), and the reason m... BACKGROUND: It is suspected that dissociation, destruction or synthetic disorder of microtubule-associated protein 2 (MAP-2) may participate in secondary injury of intracerebral hemorrhage (ICH), and the reason may be related to thrombin in high concentration after ICH; therefore, the mechanism should be studied further. OBJECTIVE: To explore the effect of hirudin on expression of MAP-2 in peripheral tissue of hematom after ICH and changes of water content in brain tissue and analyze pathogenesis of thrombin in secondary injury after ICH. DESIGN : Completely randomized grouping design and controlled animal study SEn-ING : Department of Neurology, the First Affiliated Hospital of Jilin University MATERIALS : The experiment was carried out in the Neurological Laboratory of the First Affiliated Hospital of Jilin University from April 2003 to April 2004. A number of 80 healthy Wistar rats, of both genders, aged 3-4 months, weighing 250-350 g, were randomly divided into 8 groups: normal control group, 6-hour ICH group, 1-day ICH group, 2-day ICH group, 3-day ICH group, 7-day ICH group, 3-day hirudin group and 7-day hirudin group with 10 in each group. Five rats from each group were selected to measure their water content, and the others were undertaken immunohistochemical stain. Hirudin was produced by Sigma Company, USA, and MAP-2 rabbit-rat polyclonal antibody was provided by Fuzhou Maixin Biotechnology Company Limited. METHODS: ① Model establishing and grouping intervention: Rats in simple ICH group were collected their blood from tails and then inserted with 50 μL non-anticoagulant auto-arterial blood into the cauda of the putamen in right brain within 5 minutes. Rats in hirudin groups were inserted with 10 U hirudin (which was diluted with saline to 20 μL) into local hematom regions within 5 minutes, and the needle was pulled out after 10 minutes. Rats in normal control group were untouched. ② Water content in peripheral tissue of hematom: Based on the ratio between dry weight and wet weight, brain tissue at bleeding side and in right frontal lobe was selected to measure dry and wet weights so as to calculate the water content [(wet weight - dry weight) /wet weight] × 100%.③ Positive expression of MAP-2: Based on immunohistochemical stain, positive MAP-2 cells were regarded as neurons and they were buffy morphological. Positive rate of MAP-2 was calculated, i.e., percentage of positive cells in each sight to total cells in all sights. ④ Statistical analysis: Data among groups were compared with one-way analysis of variance, averages were compared with SNK-q test by each other, and relation between water content and MAP-2 was analyzed with linear regression technique. MAIN OUTCOME MEASURES: Changes of water content and MAP-2 expression in peripheral tissue of hematorn at various time points after ICH and intervention of hirudin. RESULTS: All 80 rats were involved in the final analysis. ①Water content: Water content was increased at day 1, reached peak at day 3 and decreased at day 7. It was (72.31±0.32)%, (77.42±0.53)%, (78.44±0.28)%, (74.10±0.13)%, (74.85±0.51)% and (70.07±0.36)%, respectively in 1-day, 2-day, 3-day and 7-day ICH groups and 3-day and 7-day hirudin groups, which was higher than that in normal control group (63.85±0.41, q=-4.684 3 to -7.262 0, P〈 0.05); that in 2-day and 3-day ICH groups was higher than that in 7-day ICH group (q=-3.053 4, -3.727 0, P 〈 0.05); and that in 3-day and 7-day ICH groups was higher than that in hirudin groups at the same time points (q=-2.965 6, -2.726 4, P 〈 0.05). ②Positive expression of MAP-2: Positive expression of MAP-2 was decreased at 6 hours after ICH, reached the lowest value at day 3 and increased at day 7. Positive rate was (78.60±0.42)%, (60.56±0.74)%, (44.60±0.26)%, (25.45±0.85)%, (32.55±0.64)%, (37.69+0.76)%, (41.75±0.68)%, respectively in 6-hour, 1-day, 2-day, 3-day and 7-day ICH groups and 3-day and 7-day hirudin groups, which was lower than that in normal control group [(96.50±0.33)%, q= -3.074 5 to -8.128 5, P 〈 0.05]. In addition, positive cells of MAP-2 disappeared plentifully at 3-7 days after ICH, stain of positive cells were light, and only stain of plasma was positive. That in 3-day and 7-day hirudin groups was higher than that in ICH groups at the same time points (q= -3.391 8, -2.967 9, P 〈 0.05). Moreover, positive cells of MAP-2 was formed slightly but deeply stained. ③ Results of linear regression: Water content was negatively related to MAP-2 changes at 7 days after ICH (r= -0.894 9, P〈 0.01), i.e., water content was increased with decrease of MAP-2 expression. CONCLUSION : The deterioration of MAP-2 may be involved in the pathogenesis of thrombin within the first week after ICH, and the local administration of hirudin can protect neurons. 展开更多
关键词 ICH Interventional effect of hirudin on the expression of microtubule-associated protein 2 in peripheral tissue of hematom of model
暂未订购
Topological Expression Model of Satellite Gear Mechanism
7
作者 杨平 《Journal of Southwest Jiaotong University(English Edition)》 2005年第1期39-43,共5页
By investigation of the topological characteristics of the kinematic structure of Satellite Gear Mechanism (SGM) with graph theory, the graph model of SGM is analyzed, and a topological expression model between input ... By investigation of the topological characteristics of the kinematic structure of Satellite Gear Mechanism (SGM) with graph theory, the graph model of SGM is analyzed, and a topological expression model between input and output of SGM is established based on systematic design point. Meanwhile, the mathematical expression for SGM is deduced by integrating matrix theory and graph theory; thus, the topological characteristics of the kinematic structure of SGM can be converted into a matrix model, and the topological design problem of SGM into a matrix operation problem. In addition, a brief discussion about the measures for identification of isomorphism of the graph mode is made. 展开更多
关键词 Satellite gear mechanism Graph model Topological expression
在线阅读 下载PDF
Assistive Devices and Clothing: Exploring Adaptive Clothing Needs for Women with Lower Limb Prostheses Using the FEA Model 被引量:1
8
作者 Mastourah Al Asmari Mirahan Farag Zedan 《Open Journal of Applied Sciences》 2024年第10期2901-2922,共22页
This study aimed to comprehensively investigate the essential considerations in designing adaptive clothing for women with lower limb prostheses in Saudi Arabia. Employing a qualitative methodology, the research entai... This study aimed to comprehensively investigate the essential considerations in designing adaptive clothing for women with lower limb prostheses in Saudi Arabia. Employing a qualitative methodology, the research entailed semi-structured, in-depth interviews with women utilizing lower limb prostheses and prosthetic specialists. This approach was selected to unearth pivotal design prerequisites and comprehend the specific challenges these women encounter within the realm of clothing. The utilization of selective sampling facilitated the collection of intricate and valuable insights. A Functional, Expressive, and Aesthetic (FEA) User Needs model was utilized to scrutinize participant feedback. Functional requisites encompass ease of dressing and undressing, accessibility to the prosthetic limb, comfort, mobility with the prosthesis, and appropriate fit. Additionally, participants highlighted various expressive needs, including privacy preservation, modesty, camouflaging disability appearances, maintaining alignment with non-disabled women’s fashion, and considerations about the aesthetic aspects of garments. 展开更多
关键词 Assistive Devices Adaptive Clothing Lower Limb Prosthetics Functional expressive and Aesthetic (FEA) model
暂未订购
教研员胜任力评价体系研究:模型建构及验证
9
作者 顾金玲 李鑫 《基础教育》 北大核心 2025年第1期93-103,共11页
教研工作是基础教育高质量发展的重要支撑。教研员胜任力影响着教研功能的发挥,构建一套综合且全面的教研员胜任力评价体系有助于明确教研员工作职能、评价教研员专业能力、促进教研员专业发展。本研究通过系统梳理教研员胜任力的核心... 教研工作是基础教育高质量发展的重要支撑。教研员胜任力影响着教研功能的发挥,构建一套综合且全面的教研员胜任力评价体系有助于明确教研员工作职能、评价教研员专业能力、促进教研员专业发展。本研究通过系统梳理教研员胜任力的核心要素确定教研员胜任力层次结构模型,继而对教研员胜任力层次结构模型进行表现性评价及验证,最终形成教研员胜任力评价体系。研究结果表明,教研员胜任力评价体系凸显了教研员的核心品质,构建了基于真实情境的评价指标,促进教研员专业水平的提升,具有良好的应用价值。未来对教研员胜任力评价体系的研究应聚焦评价标准、评价内容、评价方法、评价机制的建设。对教研员胜任力评价体系的研究不仅为教研员提供了科学化的评价方法和评价依据,同时也是进一步加强教研队伍建设、促进基础教育高质量发展的必然要求。 展开更多
关键词 教研员胜任力 模型建构 表现性评价
在线阅读 下载PDF
基于循环肿瘤细胞的肺腺癌预后模型的构建与验证
10
作者 黄兴 冯一鹏 +3 位作者 陈辰 李少邱 丁翰林 马大伟 《东南大学学报(医学版)》 2025年第4期525-533,共9页
目的:筛选与肺腺癌(lung adenocarcinoma,LUAD)转移和生存预后密切相关的循环肿瘤细胞(circulating tumor cells,CTCs)差异表达基因,构建基于CTCs的LCD风险评分模型,并评估其在LUAD患者预后中的临床应用价值。方法:从GSE249262数据库获... 目的:筛选与肺腺癌(lung adenocarcinoma,LUAD)转移和生存预后密切相关的循环肿瘤细胞(circulating tumor cells,CTCs)差异表达基因,构建基于CTCs的LCD风险评分模型,并评估其在LUAD患者预后中的临床应用价值。方法:从GSE249262数据库获取LUAD患者的CTCs基因表达数据,从TCGA数据库获取439例LUAD患者的肿瘤组织RNA测序数据。通过LASSO回归和Cox比例风险回归分析,筛选出与LUAD预后显著相关的CTCs关键基因。基于这些基因构建LCD风险评分模型,并在3个独立验证集(GSE31210、GSE8894和GSE26939)及南京医科大学附属肿瘤医院的67例LUAD患者队列中进行验证,使用Kaplan-Meier生存分析和受试者工作特征(ROC)曲线评估模型的预测效能。结果:共筛选出6个与LUAD预后密切相关的CTCs关键基因,即TXN、PLP2、H2AFZ、LPGAT1、TFG和BZW1。构建的LCD风险评分模型在训练集和验证集中预测1年、3年和5年生存率的ROC曲线下面积(AUC)均超过0.60。Kaplan-Meier分析显示高风险组总生存期(OS)显著低于低风险组(HR=2.48,P<0.01)。功能富集分析表明,CTCs差异基因主要参与细胞周期调控、染色体分离和免疫逃逸等过程。进一步分析显示,PLP2和LPGAT1的高表达与不良预后显著相关(PLP2:HR=2.0,P=0.0013;LPGAT1:HR=1.8,P=0.0039)。结论:本研究成功构建并验证了一个基于CTCs关键基因的LCD风险评分模型,可为个性化治疗和精准预后评估提供潜在的临床应用价值。 展开更多
关键词 肺腺癌 循环肿瘤细胞 LASSO回归分析 差异基因表达 预后模型
暂未订购
面向历史人物事迹的叙事地图设计与实现
11
作者 赫晓慧 姬柔佳 +1 位作者 刘传 田智慧 《测绘科学》 北大核心 2025年第2期194-204,共11页
针对当前学术界对历史人物事迹叙事地图设计理论与方法关注不足的局限性,该文基于历史人物事迹的时空特征,引入叙事二分法理论,提出构成历史人物事迹叙事空间的四要素“足迹脉络、人物、背景、情景”及历史事迹叙事四面体模型,并以事件... 针对当前学术界对历史人物事迹叙事地图设计理论与方法关注不足的局限性,该文基于历史人物事迹的时空特征,引入叙事二分法理论,提出构成历史人物事迹叙事空间的四要素“足迹脉络、人物、背景、情景”及历史事迹叙事四面体模型,并以事件、场景和色彩建构叙事地图的时间、空间和情感维度,实现叙事空间的表达。在此基础上,详细阐述武则天·登封叙事地图的设计与实现过程,运用叙事地图重现事件情景,为其他历史人物事迹的相关研究提供参考。 展开更多
关键词 叙事地图 历史人物事迹 叙事四面体模型 叙事空间表达
原文传递
柑橘大实蝇气味结合蛋白基因BminOBP5的分子特征及其原核表达
12
作者 田晓丽 刘毅 +4 位作者 毛永娜 李钰华 王福莲 桂连友 张国辉 《西南农业学报》 北大核心 2025年第9期1937-1943,共7页
【目的】对柑橘大实蝇(Bactrocera minax)气味结合蛋白基因BminOBP5进行分子特征分析与原核表达,为深入探究BminOBP5的功能特点和作用机制奠定基础。【方法】采用RT-PCR技术扩增柑橘大实蝇BminOBP5基因,并进行序列分析;利用生物信息学... 【目的】对柑橘大实蝇(Bactrocera minax)气味结合蛋白基因BminOBP5进行分子特征分析与原核表达,为深入探究BminOBP5的功能特点和作用机制奠定基础。【方法】采用RT-PCR技术扩增柑橘大实蝇BminOBP5基因,并进行序列分析;利用生物信息学在线软件Expasy的ProtParam模块预测BminOBP5蛋白的理化性质;利用MEGA5.1软件分析BminOBP5与其他昆虫OBP序列的亲缘关系;通过同源建模技术构建BminOBP5的3D模型;以原核表达系统和镍柱表达纯化BminOBP5融合蛋白。【结果】BminOBP5开放阅读框长444 bp,编码147个氨基酸残基,氨基端含有20个氨基酸残基组成的信号肽,序列中具有6个保守半胱氨酸残基,属于Classic OBP亚家族。BminOBP5蛋白的预测分子量为13.89 kD,是小分子量蛋白;理论等电点为4.97,为酸性蛋白;亲水性总平均值(GRAVY)为-0.383(<0),是亲水性蛋白。进化树分析显示BminOBP5与黑腹果蝇DmelOBP28a聚在同一分支,其氨基酸序列一致性(46%)以及三级结构(RMSD=0.131A)均非常相似,表明这2个OBPs应具有相似的功能特点。经IPTG(0.5 mmol/L)在37℃、200 r/min条件下诱导含有重组表达载体(pET-32a-BminOBP5)的大肠杆菌BL21(DE3)7 h后,细菌细胞成功表达出一个分子量约为13 kD的目的蛋白,与预期大小一致。同时根据镍柱(Ni-NTA His Bind Resin纯化树脂)使用说明书纯化目的蛋白。【结论】在原核细胞中成功表达了柑橘大实蝇BminOBP5基因,为进一步探究BminOBP5的功能特点和作用机制奠定了良好分子基础。 展开更多
关键词 柑橘大实蝇 气味结合蛋白 序列分析 同源建模 异源表达
在线阅读 下载PDF
基于改进VGG16网络的失能老人表情识别研究
13
作者 何巍 李苏 《四川师范大学学报(自然科学版)》 2025年第3期383-391,共9页
为能更好地关注失能老人的情绪状态,采用VGG16作为表情识别的基础模型,并在此基础上进行优化改进.首先,在特征层上将激活函数改用SiLU函数,并添加批归一化层;然后,在分类层上采用自适应平均池化处理图像,同时利用卷积层实现全连接效果,... 为能更好地关注失能老人的情绪状态,采用VGG16作为表情识别的基础模型,并在此基础上进行优化改进.首先,在特征层上将激活函数改用SiLU函数,并添加批归一化层;然后,在分类层上采用自适应平均池化处理图像,同时利用卷积层实现全连接效果,避免参数过多和过拟合问题;最后,通过SENet通道注意力机制迭代式地融合相同通道数的卷积层,实现浅层与深层特征的交互,丰富人脸表情特征提取.实验结果表明,在FER2013和CK+数据集上的识别准确率分别达到72.50%和98.70%,与基础方法对比分别提高8.20%和3.90%,实验表明改进的方法能够提高表情识别率,具有一定的先进性. 展开更多
关键词 VGG16 表情识别 自适应平均化 通道注意力机制
在线阅读 下载PDF
Lieber-DeCarli酒精性肝损伤小鼠模型的转录组学分析 被引量:2
14
作者 阮天音 王四园 +4 位作者 李旭涛 张昊 彭渊 刘成海 陶艳艳 《中国实验动物学报》 北大核心 2025年第2期204-215,共12页
目的 分析Lieber-DeCarli酒精性肝损伤小鼠模型的转录组学特点。方法 雄性C57BL/6J小鼠18只,随机分成酒精饲料组10只和对照组8只。酒精饲料组喂养Lieber-DeCarli酒精饲料,先以10~57.3 mL/L递增量的95%酒精饲料适应性喂养1周,再以57.3 mL... 目的 分析Lieber-DeCarli酒精性肝损伤小鼠模型的转录组学特点。方法 雄性C57BL/6J小鼠18只,随机分成酒精饲料组10只和对照组8只。酒精饲料组喂养Lieber-DeCarli酒精饲料,先以10~57.3 mL/L递增量的95%酒精饲料适应性喂养1周,再以57.3 mL/L 95%酒精饲料喂养2周,共3周;对照组同时喂养对照饲料。处死小鼠留取血清和肝组织,试剂盒检测血清谷丙转氨酶(ALT)、谷草转氨酶(AST)与肝组织总胆固醇(TC)、甘油三酯(TG)、还原型谷胱甘肽(GSH)、总超氧化物歧化酶(T-SOD)、丙二醛(MDA)含量;ELISA法测定小鼠肝组织炎症因子白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)和转化生长因子-β1(TGF-β1)水平,并用qRT-PCR验证IL-6、TNF-α、TGF-β1基因表达。苏木素-伊红(HE)、油红O染色观察肝组织病理变化;通过免疫组织化学染色法,使用F4/80抗体检测巨噬细胞的表达变化。RNA-seq分析两组肝组织差异基因并进行GO和KEGG分析,再以qRT-PCR验证差异基因表达。结果 与对照组比较,酒精饲料组小鼠体质量显著下降(P<0.01);血清ALT、AST水平显著升高(P<0.01),肝组织TC、TG、MDA水平显著升高(P<0.05),GSH、T-SOD含量显著下降(P<0.05);组织中炎症因子IL-6,TNF-α与TGF-β1水平上升,以qRT-PCR验证结果相一致(P<0.05)。肝小叶结构破坏,呈现大泡脂肪变性、微泡性脂肪变性及气球样变性;肝组织中脂滴显著增多,巨噬细胞表达增加。以|log2FC|>1且q<0.05为筛选条件,获得2063个差异基因,其中1236个基因上调,827个基因下调。主要在细胞色素P450对外源性物质的代谢、细胞因子与细胞因子受体的相互作用、趋化因子信号通路、类固醇激素生物合成、谷胱甘肽代谢、视黄醇代谢等通路富集(P<0.05)。qRT-PCR验证其中显著上调(Mmp12、Gstm3、Cyp2a22等)与下调(Serpina1e、Acmsd、Mup3d等)的差异基因各10个,与转录组测序结果一致。结论 酒精性肝损伤主要病理机制涉及细胞色素P450对外源性物质的代谢、细胞因子与细胞因子受体的相互作用、趋化因子信号通路、谷胱甘肽代谢、视黄醇代谢等通路。 展开更多
关键词 酒精性肝损伤 Lieber-DeCarli模型 基因表达 转录组学
在线阅读 下载PDF
面向PDM的产品及其零部件的EXPRESS模型 被引量:3
15
作者 张思荣 谭建荣 《计算机辅助设计与图形学学报》 EI CSCD 北大核心 2001年第10期918-925,共8页
对产品及其零部件进行正确建模是 PDM系统实现的前提和关键 .文中针对现有 STEP应用协议存在的局限性进行了合理的扩充 ,建立了产品及产品版本类、产品定义关系类等产品及其零部件的 EXPRESS模型 ,开发了基于该模型的 PDM系统 ,实现了... 对产品及其零部件进行正确建模是 PDM系统实现的前提和关键 .文中针对现有 STEP应用协议存在的局限性进行了合理的扩充 ,建立了产品及产品版本类、产品定义关系类等产品及其零部件的 EXPRESS模型 ,开发了基于该模型的 PDM系统 ,实现了产品的结构管理、配置管理、以及产品相关信息的集成管理 。 展开更多
关键词 产品配置管理 PDM CIMS express模型 零部件
在线阅读 下载PDF
面向多目标模式的EXPRESS模型转换 被引量:2
16
作者 杨子江 黄益民 董金祥 《计算机辅助设计与图形学学报》 EI CSCD 北大核心 2005年第4期800-805,共6页
提出一种系统化的模型转换方法,实现EXPRESS模型向多种目标模型的转换文中系统分为模式无关层、半模式相关层与模式相关层,分别处理模式转换中不同阶段的信息论述了EXPRESS模型转换的一些关键技术,包括EXPRESS继承关系和约束在对象模型... 提出一种系统化的模型转换方法,实现EXPRESS模型向多种目标模型的转换文中系统分为模式无关层、半模式相关层与模式相关层,分别处理模式转换中不同阶段的信息论述了EXPRESS模型转换的一些关键技术,包括EXPRESS继承关系和约束在对象模型、关系模型与结构化模型中的表达利用文中方法,可将具体的模型转换归结到某一类别并利用现有框架实现。 展开更多
关键词 express建模语言 数据模型 模式转换
在线阅读 下载PDF
1种ABO等位基因新突变组合鉴定及蛋白结构分析
17
作者 杨红梅 马思飞 +2 位作者 邹昕 钱程 徐立 《现代医药卫生》 2025年第8期1809-1813,共5页
目的分析1种ABO等位基因新突变组合标本的血清学和分子生物学特征,结合蛋白三维结构模型探究其遗传分子机制。方法2023年10月该实验室采用常规血清学方法对1例无偿献血的先证者及家系成员进行ABO血型鉴定,使用Sanger测序进行ABO基因分型... 目的分析1种ABO等位基因新突变组合标本的血清学和分子生物学特征,结合蛋白三维结构模型探究其遗传分子机制。方法2023年10月该实验室采用常规血清学方法对1例无偿献血的先证者及家系成员进行ABO血型鉴定,使用Sanger测序进行ABO基因分型,采用PacBio三代长读单分子实时测序分析ABO全基因包括侧翼调控区域,使用DynaMut构建野生型和突变型糖基转移酶(GTA)三维分子模型,通过PROVEAN和PolyPhen2预测突变对酶功能及蛋白稳定性的影响。结果先证者和父亲血清学结果均为AweakB,基因分型结果为Ax24/B101;ABO基因检测结果与ABO*A1.01序列对比:2个样本均存在297A>G、467C>T、526C>G、657C>T、703G>A、796C>A、803G>C、838C>T和903G>A突变,在ISBT数据库中暂未检索到此种突变组合基因型;三代测序为ABO*A3.new/ABO*B.01,导致多肽链p.Leu280Phe(L280F)替换。GTA三维分子建模提示L280F突变导致蛋白结构中氢键和水介导氢键数量减少,相应弱氢键、弱水介导氢键数量增加和原子间相互作用发生变化影响蛋白结构的稳定性。结论在ABO第7外显子发现1种新的等位基因突变组合——467C>T、838C>T,该错义突变导致氨基酸替换影响酶活性改变,从而出现A抗原弱表达现象,且能稳定遗传。 展开更多
关键词 ABO基因 抗原弱表达 基因测序 3D分子模型
暂未订购
马尔可夫基因表达建模的神经网络矩闭合方法
18
作者 顾冬洋 姜庆超 《华东理工大学学报(自然科学版)》 北大核心 2025年第1期70-80,共11页
生物体的生命活动与基因表达密切相关,然而现有的基因表达矩闭合近似建模方法难以充分利用生化反应过程的潜在细节信息。本文提出了一种基于人工神经网络的矩闭合方法,其利用神经网络学习到矩方程组中高阶矩的低阶表示,使方程组实现闭合... 生物体的生命活动与基因表达密切相关,然而现有的基因表达矩闭合近似建模方法难以充分利用生化反应过程的潜在细节信息。本文提出了一种基于人工神经网络的矩闭合方法,其利用神经网络学习到矩方程组中高阶矩的低阶表示,使方程组实现闭合,并进一步结合常微分方程求解器对闭合后的方程组进行求解,最终获得精确的矩估计。实验结果表明,所提方法在预测精度和计算效率上显著优于传统方法。 展开更多
关键词 基因表达建模 神经网络 矩闭合方法 随机模拟 最大熵原理
在线阅读 下载PDF
基于机器学习的蛋白质重组表达序列优化研究进展
19
作者 王世成 杨劲秋 +2 位作者 赵伟睿 胡升 梅乐和 《中国生物工程杂志》 北大核心 2025年第6期49-61,共13页
蛋白质重组表达是生物工程研究与应用的一个关键环节,实现蛋白质高水平、高活性表达具有重要的理论价值与实践意义。长期以来,对蛋白质重组表达水平的优化大多聚焦于考察和优化重组表达体系构成、重组工程菌的培养条件及诱导条件等外部... 蛋白质重组表达是生物工程研究与应用的一个关键环节,实现蛋白质高水平、高活性表达具有重要的理论价值与实践意义。长期以来,对蛋白质重组表达水平的优化大多聚焦于考察和优化重组表达体系构成、重组工程菌的培养条件及诱导条件等外部因素,对蛋白质编码序列、调控序列等内部因素的研究相对较少。随着生物信息学、计算生物学与人工智能技术的快速发展与深度融合,人们尝试利用机器学习方法构建蛋白质表达水平预测模型或蛋白质序列生成模型,再基于模型进行蛋白质序列的智能优化或从头设计。这种策略不仅能有效提升蛋白质重组表达序列优化的精准度和效率,还能为深入解析蛋白质表达水平调控机制提供新的研究视角,因而引起了众多研究者的关注和重视。总结了近年来机器学习在蛋白质重组表达序列优化与设计领域的最新研究进展,重点分析讨论了代表性机器学习模型的构建方法与序列优化策略,以及如何突破训练数据的局限性、提升模型可解释性等有待解决的关键问题。 展开更多
关键词 蛋白质重组表达 序列优化 表达预测模型 序列生成模型 机器学习
原文传递
CHECKING CONSISTENCY IN INFORMATION MODELS BY USING CONSTRAINT PROGRAMMING
20
作者 方捷 KAHN Hilary J CARPENTER Andy 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2005年第1期30-37,共8页
This paper addresses the issue of checking consistency in information models. A method based on constraint programming is proposed for identifying inconsistency or proving consistency in information models. The system... This paper addresses the issue of checking consistency in information models. A method based on constraint programming is proposed for identifying inconsistency or proving consistency in information models. The system described here checks information models written in the ISO standard information modelling language EXPRESS. EXPRESS is part of the ISO STEP standard used in the manufacturing and process industries. This paper describes the checking procedure, including EXPRESS model formalization, constraint satisfaction problem (CSP) derivation from the formalized model and satisfaction checking of the derived CSPs. This paper shows a new domain in which constraint programming can be exploited as model verification and validation. 展开更多
关键词 express model constraint programming model verification
在线阅读 下载PDF
上一页 1 2 94 下一页 到第
使用帮助 返回顶部