检索结果-南通市图书馆

Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2008年第12期9卷 982-989页

作者： Li-juan XIE xing-qian ye Dong-hong LIU Yi-bin YING College of Biosystems Engineering and Food Science Zhejiang University Hangzhou 310029 China

Near-infrared (NIR) spectroscopy combined with chemometrics techniques was used to classify the pure bayberry juice and the one adulterated with 10% (w/w) and 20% (w/w) water. Principal component analysis (PCA) was applied to reduce the dimensions of spectral data, give information regarding a potential capability of separation of objects, and provide principal component (PC) scores for radial basis function neural networks (RBFNN). RBFNN was used to detect bayberry juice adulterant. Multiplicative scatter correction (MSC) and standard normal variate (SNV) transformation were used to preprocess spectra. The results demonstrate that PC-RBFNN with optimum parameters can separate pure bayberry juice samples from water-adulterated bayberry at a recognition rate of 97.62%, but cannot clearly detect water levels in the adulterated bayberry juice. We conclude that NIR technology can be successfully applied to detect water-adulterated bayberry juice.

关键词： Near-infrared (NIR) spectroscopy Principal component-radial basis function neural networks (PC-RBFNN) Bayberry juice Adulteration Chemometrics technique

Analysis of volatile components in a Chinese fish sauce,Fuzhou Yulu, by gas chromatography-mass spectrometry

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2008年第12期9卷 977-981页

作者： Yuan-fan YANG Shen-ru CHEN Hui NI xing-qian ye School of Biosystem Engineering and FoodScience Zhejiang University Hangzhou 310029 China School of Bioengineering Jimei University Xiamen 361021 China

Volatile components of Fuzhou Yulu, a Chinese fish sauce, were analyzed by gas chromatography-mass spectrometry （GC-MS）, and two pretreatment methods, i.e., purge and trap （P＆T） GC-MS and ethyl acetate extraction followed by GC-MS, were compared. P＆T-GC-MS method determined 12 components, including sulfur-containing constituents （such as dimethyl disulfide）, nitrogen-containing constituents （such as pyrazine derivatives）, aldehydes and ketones. Ethyl acetate extraction fol- lowed by GC-MS method detected 10 components, which were mainly volatile organic acids （such as benzenepropanoic acid） and esters. Neither of the two methods detected alcohols or trimethylamine. This study offers an important reference to determine volatile flavor components of traditional fish sauce through modem analysis methods.

关键词： Fish sauce Fuzhou Yulu Volatile component Purge and trap Gas chromatography-mass spectrometry (GC-MS)

Microstructures and properties of Al_2O_3 dispersion-strengthened copper alloys prepared through different methods

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2016年第12期23卷 1437-1443页

作者： Zhi-qiao Yan Feng Chen Fu-xing ye Dong-ping Zhang Yi-xiang Cai Guangdong Institute of Materials and Processing Guangdong Academy of Sciences State Key Laboratory of Powder Metallurgy Central South University

Al2O3 dispersion copper alloy powder was prepared by intemal oxidation, and three consolidation methods--high-velocity compaction （HVC）, hot pressing （HP）, and hot extrusion （HE）--were used to prepare Al2O3 dispersion-strengthened copper （Cu-Al2O3） alloys. The microstructures and properties of these alloys were investigated and compared. The results show that the alloys prepared by the HP and HE methods exhibited the coarsest and finest grain sizes, respectively. The alloy prepared by the HVC method exhibited the lowest relative density （98.3% vs. 99.5% for HP and 100% for HE）, which resulted in the lowest electrical conductivity （81% IACS vs. 86% IACS for HP and 87% IACS for HE）. However, this alloy also exhibited the highest hardness （77 HRB vs. 69 HRB for HP and 70 HRB for HE）, the highest compressive strength （443 MPa vs. 386 MPa for I/P and 378 MPa for HE）, and the best hardness retention among the investigated alloys. The results illustrate that the alloy prepared by the HVC method exhibits high softening temperature and good mechanical properties at high temperatures, which imply long service life when used as spot-welding electrodes.

关键词： dispersion-strengthened alloys copper alloys alumina preparation methods microstructure properties

铈掺杂对α-Bi_(2)Mo_(3)O_(12)纳米片催化剂丙烯选择性氧化性能的影响

在线全文

学校读者我要写书评

暂无评论

现代化工 2024年第7期44卷 145-150页

作者：张鑫杨艳艳周如金许松泠单书峰曾兴业吉林化工学院化学与制药工程学院吉林吉林132000 广东石油化工学院广东高校劣质油加工重点实验室广东茂名525000 华南理工大学化学与化工学院广东广州510000

采用快速微波辅助水热法制备了4种不同的Bi_(2-x)Ce_(x)Mo_(3)O_(12)纳米片催化剂。在制备过程中通过调节铈的掺杂量可以改变合成催化剂的形貌和结构,成功地提高了Bi_(2-x)Ce_(x)Mo_(3)O_(12)纳米片催化剂的比表面积。结果表明,煅烧温度... 详细信息

采用快速微波辅助水热法制备了4种不同的Bi_(2-x)Ce_(x)Mo_(3)O_(12)纳米片催化剂。在制备过程中通过调节铈的掺杂量可以改变合成催化剂的形貌和结构,成功地提高了Bi_(2-x)Ce_(x)Mo_(3)O_(12)纳米片催化剂的比表面积。结果表明,煅烧温度为500℃、pH为3、掺杂量x=0.05时制备的Bi_(2-x)Ce_(x)Mo_(3)O_(12)纳米片催化剂具有最高的丙烯选择性氧化性能,丙烯转化率为42.1%,丙烯醛选择性为88.3%。Bi_(2-x)Ce_(x)Mo_(3)O_(12)纳米片催化剂的性能与结晶度呈负相关。用XPS表征了Bi_(2-x)Ce_(x)Mo_(3)O_(12)的氧迁移率,Bi_(2-x)Ce_(x)Mo_(3)O_(12)的催化性能与其氧流动性呈正相关。

关键词： Bi2-xCexMo3O12 丙烯丙烯醛

麻花艽内生真菌群落多样性及土壤理化因子相关性研究

在线全文

学校读者我要写书评

暂无评论

青海农林科技 2024年第3期 1-7,16页

作者：郑坤胡星强孟静叶星王敏周党卫青海民族大学药学院青藏高原植物化学重点实验室青海西宁810007 中国科学院西北高原生物研究所高原生物适应与进化重点实验室青海西宁810008

本文以高寒草甸的麻花艽(Gentiana straminea Maxim.)为研究对象,采用组织块培养法对麻花艽根、花、茎和叶四个组织部位的内生真菌进行分离,经形态学及ITS测序鉴定后分析麻花艽内生真菌的多样性。结果显示,麻花艽不同组织部位中共获得26... 详细信息

本文以高寒草甸的麻花艽(Gentiana straminea Maxim.)为研究对象,采用组织块培养法对麻花艽根、花、茎和叶四个组织部位的内生真菌进行分离,经形态学及ITS测序鉴定后分析麻花艽内生真菌的多样性。结果显示,麻花艽不同组织部位中共获得268株内生真菌,共聚类为40个OTUs。根、花、茎和叶部位的较优势菌属依次为刚毛藻属(Cladophora),灰葡萄孢属(Botrytis),枝孢菌属(Cladosporium)和壳针孢菌属(Septoria)。内生真菌群落多样性指数(Shannon指数、Simpson指数)均为根部较高。根和茎部位内生真菌群落结构相近,差异较小。土壤pH、全氮、全钾、速效磷和容重是麻花艽内生真菌群落多样性的主要影响因子。

关键词：麻花艽内生真菌 α多样性土壤理化性质

在线全文

学校读者我要写书评

暂无评论

带线锚钉+空心钉内固定治疗髌骨骨折的疗效

临床骨科杂志 2024年第2期27卷 257-260页

作者：王强吕欣李兴业刘晋元山西医科大学第二医院创伤骨科山西太原030001

目的探讨带线锚钉+空心钉内固定治疗髌骨骨折的疗效。方法将60例髌骨骨折患者按照内固定方式不同分为观察组(采用带线锚钉+空心钉内固定治疗,30例)和对照组(采用克氏针张力带+钢丝捆扎内固定治疗,30例)。记录两组手术时间、骨折愈合情... 详细信息

目的探讨带线锚钉+空心钉内固定治疗髌骨骨折的疗效。方法将60例髌骨骨折患者按照内固定方式不同分为观察组(采用带线锚钉+空心钉内固定治疗,30例)和对照组(采用克氏针张力带+钢丝捆扎内固定治疗,30例)。记录两组手术时间、骨折愈合情况、术后并发症发生率。采用Lysholm评分评价膝关节功能。结果患者均获得随访,观察组随访时间12~36(17.47±6.17)个月,对照组随访时间12~30(17.70±4.06)个月。手术时间观察组短于对照组(P0.05)。结论带线锚钉+空心钉内固定治疗髌骨骨折能有效缩短手术时间、降低手术难度、减少术后并发症的发生,而且内固定稳定、牢靠,患者术后膝关节功能恢复良好。

关键词：髌骨骨折带线锚钉空心钉克氏针张力带膝关节功能

Biological Fingerprinting Analysis of Interaction Between Taxoids in Taxus and Microtubule Protein by Microdialysis Coupled with High-performance Liquid Chromatography/Mass Spectrometry for Screening Antimicrotubule Agents

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2008年第4期24卷 411-419页

作者： LEI Xiao-yuan KONG Liang SU xing-ye GUO Ming ZOU Han-fa National Chromatographic R＆A Center Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 P. R. China College of Marine Environmental Engineering Dalian Fisheries University Dalian 116023 P R. China Department of Chemistry and Chemical Technology Dalian University Dalian 116622 P. R. China

Some natural products, such as traditional Chinese medicines（TCMs）, contain compounds with anticancer activity and have attracted a great interest in recent years as alternative anticancer therapies. A quick and convenient assay for screening antimicrotubule compounds in which in vitro microdialysis/high-performance liquid chromatography （HPLC） is used to monitor the binding of the compounds extracted from TCM Taxus cuspidata Siebold ＆ Zucc（Taxus） to microtubules is reported. It was observed that the extract of Taxus contains at least five compounds which have affinity interaction with microtubules by biological fingerprinting analysis, and they were identified as the taxoids of taxol, baccatin III, 10-deacetylbaccatin Ⅲ（10-DAB）, cephalomannine and 7-epi-10-deacetyltaxol （7-epi-10-DAT） based on the comparison of their high-performance liquid chromatographic/mass spectrometric and UV spectra with those of the standard samples, both assembly-promoting and disassembly-inhibiting characteristics of those compounds were evaluated. It was observed that baccatin Ⅲ and 10-DAB bound to microtubules and the binding degrees were influenced by GTP. Competitive binding behavior of taxol with other four taxoids to microtubules was also investigated.

关键词： Microdialysis/high-performance liquid chromatography(HPLC) Biological fingerprinting analysis Taxoids Microtubule Taxus

Two Novel Cobalt(Ⅱ)/nickel(Ⅱ) Metal-organic Coordination Polymers Based on Flexible Polycarboxylic Acids and Rigid Bis(imidazole) Mix Ligands

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2020年第1期39卷 147-153,5页

作者： YANG Ming-xing YAN Zhi-Wei CHEN Li-Juan LIN xing-ye LIN Shen College of Chemistry and Materials Science Fujian Normal UniversityFuzhouFujian 350007China

Two novel metal-organic coordination compounds, [Co2(OH)(chdc)1.5(bibp)]n(1) and [Ni(chdc)(bib)]n·2nH2O(2, H2chdc=1,4-cyclohexanedicarboxylic acid, bibp=4,4’-bis(1-imidazolyl)biphenyl, bib=1,4-bis(1-imidazolyl)benzene), were synthesized and characterized. Compound 1 crystallizes in monoclinic system, space group PI with a=10.591(3), b=11.146(3), c=12.264(3) ?, α=89.009(6), β=88.397(4), γ=87.823(3)°, V=1446.0(6) ?3, Dc=1.554 g/cm3, C30H30Co2N4O7, Mr=676.44, F(000)=696, μ(MoKα)=1.202 mm-1, Z=2, R=0.0278 and wR=0.0718. In 1, it contains an interesting tetranuclear Co(Ⅱ) cluster. The neighboring {Co4} clusters are linked by chdc2-ligands to generate a 2D network. The bibp ligands connect adjacent layers to form an open 3 D metal-organic framework. Compound 2 crystallizes in monoclinic system, space group P21/n with a=8.8110(1), b=19.369(1), c=12.7379(4) ?, β=102.952(5)o, V=2118.5(2) ?3, Dc=1.490 g/cm3, C20H24N4NiO6, Mr=475.14, F(000)=992, μ(MoKα)=0.961 mm-1, Z=4, R=0.0306 and wR=0.0738. In 2, each deprotonated chdc 2-ligand links two Ni(Ⅱ) atoms to generate a 1 D chain along the a axis. The adjacent chains are further connected by bib ligands to build up an interesting two-dimensional network. Compound 1 shows antiferromagnetic property.

关键词： coordination polymer magnetic properties cobalt(Ⅱ)complex nickel(Ⅱ)complex bis(imidazole)ligand

B7-H4 expression is elevated in human U251 glioma stem-like cells and is inducible in monocytes cultured with U251 stem-like cell conditioned medium

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Cancer 2013年第12期32卷 653-660页

作者： Lian-Jie Mo Hong-xing ye Ying Mao Yu Yao Jian-Min Zhang Department of Neurosurgery Second Affiliated Hospital School of Medicine Zhejiang University Department of Neurosurgery Huashan Hospital Fudan University

Previous studies indicated that B7-H4,the youngest B7 family,negatively regulates T cell-mediated immunity and is significantly overexpressed in many human *** stem cells are purported to play a role in tumor renewal and resistance to radiation and ***,the link between B7-H4and tumor stem cells is *** this study,we investigated B7-H4 expression in the medium of human glioma U251 cell *** results showed that U251 cells cultured in serum-free medium(supplemented with 2%B27,20 ng/mL epidermal growth factor,20 ng/mL basic fibroblast growth factor)maintained stem-like cell characteristics,including expression of stem cell marker CD133 and the neural progenitor cell markers nestin and *** contrast,U251 cells cultured in serum-containing medium highly expressed differentiation marker glial fibrillary acidic *** cytometry analysis showed serum-free medium-cultured U251 cells expressed higher intracellular B7-H4 than serumcontaining medium-cultured U251 cells(24%-35%vs.8%-11%,P<0.001).Immunofluorescence in purified monocytes from normal human peripheral blood mononuclear cells revealed moderate expression of B7-H4 after stimulation with conditioned medium from U251 cells cultured in serum-containing ***,conditioned medium from U251 stem-like cells had a significant stimulation effect on B7-H4expression compared with serum-containing conditioned medium(P<0.01).Negative costimulatory molecule B7-H4 was preferentially expressed in U251 stem-like cells,and conditioned medium from these cells more effectively induced monocytes to express B7-H4 than conditioned medium from U251 cells cultured in the presence of *** results show that U251 stem-like cells may play a more crucial role in tumor immunoloregulation with high expression of B7-H4.

关键词：外周血单核细胞肿瘤干细胞条件培养基脑胶质瘤碱性成纤维细胞生长因子诱导无血清培养基 U251细胞

基于加权相位延迟指数的阿尔茨海默病静息态脑电图定量分析

在线全文

学校读者我要写书评

暂无评论

中国当代医药 2024年第10期31卷 4-9页

作者：叶星闫奕欣王荧荧石静萍南京医科大学附属脑科医院神经内科江苏南京210029

目的分析阿尔茨海默病(AD)、轻度认知功能障碍(MCI)患者定量脑电图的特征,探讨定量脑电图在早期检测和评估认知衰退方面的效用。方法本研究选取AD患者、MCI患者和认知功能正常的老年人作为研究对象,采用64导脑电图记录静息状态下脑电信... 详细信息

目的分析阿尔茨海默病(AD)、轻度认知功能障碍(MCI)患者定量脑电图的特征,探讨定量脑电图在早期检测和评估认知衰退方面的效用。方法本研究选取AD患者、MCI患者和认知功能正常的老年人作为研究对象,采用64导脑电图记录静息状态下脑电信号,通过加权相位延迟指数(wPLI)分析人组患者全脑功能连接的差异性。结果AD组在θ频段的相对功率超过对照组,在β频段则低于对照组。此外,三组间的功能连接呈现差异性。在θ和频段,AD组不同脑区之间的相位同步性增强。而在α频段中,AD组局部脑区之间功能连接强度减弱。同时,θ和β频段下的全脑电极平均相功率改变均与临床认知评估量表呈现相关关系。结论定量脑电图分析显示AD患者脑波存在频率慢化的特点。另外,AD患者同时存在脑网络皮层神经通路功能代偿和失连接现象。

关键词：阿尔茨海默病脑电图功率谱加权相位延迟指数