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71.
In this study for preparing the better performance scaffold materials for peripheral nerve repairing, the collagen‐based composite scaffolds are crosslinked with glutaraldehyde and their structure and performance are investigated. The results of FTIR indicated that the collagen and chitosan are certainly crosslinked through GTA without any significant change in the chemical property. It was observed under a scanning electron microscope (SEM) that the crosslinked collagen‐based composite scaffolds had a porous three‐dimensional cross‐linked structure. The experiments showed that the biostability of the scaffold is greatly enhanced, but the GTA crosslinking induces the potential cytotoxicity and poor hydrophilic nature. To overcome these disadvantages, the low temperature plasma technology is utilized to modify the surface of the cross‐linked collagen‐based composite scaffolds in this study. Measurements of water contact angle showed that hydrophilic nature of surface of the scaffolds was improved after low temperature plasma technology modification. The cell proliferation experiments revealed that the modified collagen‐based composite scaffolds still kept their bioactivity and benefited the proliferation. 相似文献
72.
Cellular prion protein, a membrane protein, is expressed in all mammals. Prion protein is also found in human blood as an anchorless protein, and this protein form is one of the many potential sources of misfolded prion protein replication during transmission. Many studies have suggested that β-amyloid1–42 oligomer causes neurotoxicity associated with Alzheimer''s disease, which is mediated by the prion protein that acts as a receptor and regulates the hippocampal potentiation. The prevention of the binding of these proteins has been proposed as a possible preventative treatment for Alzheimer''s disease; therefore, a greater understanding of the binding hot-spots between the two molecules is necessary. In this study, the epitope mapping immunoassay was employed to characterize binding epitopes within the prion protein and complementary epitopes in β-amyloid. Residues 23–39 and 93–119 in the prion protein were involved in binding to β-amyloid1–40 and 1–42, and monomers of this protein interacted with prion protein residues 93–113 and 123–166. Furthermore, β-amyloid antibodies against the C-terminus detected bound β-amyloid1–42 at residues 23–40, 104–122 and 159–175. β-Amyloid epitopes necessary for the interaction with prion protein were not determined. In conclusion, charged clusters and hydrophobic regions of the prion protein were involved in binding to β-amyloid1–40 and 1–42. The 3D structure appears to be necessary for β-amyloid to interact with prion protein. In the future, these binding sites may be utilized for 3D structure modeling, as well as for the pharmaceutical intervention of Alzheimer''s disease. 相似文献
73.
This special issue is dedicated to the memory of thelate Professor Wei-Shan Zhou at Shanghai Institute of Organic Chemistry,Chinese Academy of Sciences. 相似文献
74.
探讨了碳纤维(CF)表面镍金属的化学镀工艺,制备了镀镍碳纤维(NiCF),采用密炼工艺制备了ABS基体复合材料,研究了CF和NiCF含量对复合材料的导电性能及电磁屏蔽效能的影响。结果表明:采用化学镀的方法在碳纤维表面镀覆了金属镍,所形成的镀层均匀致密;镀覆时间为5min时,镀镍后的碳纤维电阻率降低两个数量级;复合材料电阻率随CF、NiCF含量的增加而逐渐减小;复合材料电磁屏蔽效能随CF、NiCF含量的增加而逐渐增加,当NiCF含量为25%(wt)(约13.3vol%)时,电磁屏蔽效能最高可达51dB。 相似文献
75.
Yang Sun Zhipeng Ran Hongyan Tang Yong Li Wenshuang Song Qingguang Ren Wuli Yang Jilie Kong 《中国化学》2013,31(6):787-793
Mesoporous silica nanoparticles (MSN) were coated by pH‐responsive polymer chitosan‐poly (methacrylic acid) (CS‐PMAA). This nano drug delivery system showed good application prospects and the polymer‐coated microspheres were promising site‐specific anticancer drug delivery carriers in biomedical field. A continuous detection of pH‐responsive drug delivery system in cells in situ, utilizing MSN/CS‐PMAA composite microspheres, was proposed. Two kinds of different cell lines, tumor cell line (Hela) and normal somatic cells (293T), were used to investigate the behaviours of the drug loaded system in the cells. Conclusions could be drawn from the fluorescent images obtained by confocal laser scanning microscopy (CLSM), modified drug‐loaded microspheres (MSN/CS‐PMAA) were ingested into cells more easily, the uptake of DOX@FITC‐MSN/CS‐PMAA by HeLa/293T cells were performed at pH 7.4/pH 6.8, DOX was released during the ingestion process, fluorescence intensity decreased with time because of efflux transport and photo‐bleaching. Fluoresence detection by flow cytometry was performed as comparison. The continuous fluorescent observation in situ could be widely used in the pH‐responsive releasing process of drug delivery system in the cells. 相似文献
76.
采用超声波辐照、臭氧氧化以及超声波辐照-臭氧氧化降解废水中的结晶紫;考察了废水初始pH、超声波功率和频率、氧气流量、反应温度等因素对降解效率的影响.结果表明:超声波和臭氧对结晶紫的降解具有协同作用;当废水溶液初始质量浓度为200mg.L-1、pH为10.0时,控制超声波功率和频率分别为100 W和30kHz,氧气流量为0.4L.min-1,反应温度为25℃,反应时间为90 min,则总有机碳(TOC)的去除率可达89.2%,相应的一级反应速率常数为2.38×10-2min-1. 相似文献
77.
大豆油煎炸过程理化指标与LF-NMR弛豫特性的相关性研究 总被引:3,自引:0,他引:3
在对大豆油无料/薯条煎炸过程[温度:(180±5)℃,持续36 h]中的酸价(AV)、粘度(V)、吸光值(A)及总极性化合物(TPC)含量等及低场核磁共振(LF-NMR)弛豫特性(峰起始时间T21、T22、T23、相应的峰面积比例S21、S22、S23、单组份弛豫时间T2W)变化规律研究的基础上,利用多元回归分析建立了理化指标与其LF-NMR检测结果的相关性模型,并进行验证。结果表明:大豆油的酸价、TPC含量及S21峰面积均随煎炸时间的延长而线性增大,T21、T22峰起始时间及T2W则随煎炸时间的延长而线性减小(r2>0.90),粘度、吸光值随煎炸时间的延长逐渐增加并符合二项式关系(r2>0.90),而T23峰起始时间及S22、S23与煎炸时间之间无明显规律性变化。煎炸薯条后,油样的酸价、粘度、TPC含量、吸光值及S21均较无料煎炸显著增大(P<0.05),而T21、T22峰起始时间及T2W显著缩短。多元回归分析表明,酸价及TPC含量与T2W、T21,粘度与T2W,吸光值与S21间均可建立良好的相关性模型(R2>0.93)。模型验证合理可靠,可通过油样的LF-NMR检测结果有效预测其理化指标的变化。 相似文献
78.
Qing-Zhong Li Wen-Ming Liu Ran Li Wen-Zuo Li Jian-Bo Cheng Bao-An Gong 《Structural chemistry》2013,24(1):25-31
The H2O···XCCNgF and H3N···XCCNgF (X = Cl and Br; Ng = Ar, Kr, and Xe) complexes have been studied with quantum chemical calculations at the MP2/aug-cc-pVTZ level. The results show that the inserted noble gas atom has an enhancing effect on the strength of halogen bond, and this enhancement is weakened with the increase of noble gas atomic number. The methyl and Li substituents in the electron donor strengthen the halogen bond. The interaction energy increases from ?3.75 kcal/mol in H3N–BrCCF complex to ?9.66 kcal/mol in H2LiN–BrCCArF complex. These complexes have been analyzed with atoms in molecules, natural bond orbital, molecular electrostatic potentials, and energy decomposition calculations. 相似文献
79.
80.
Qing Ri Li Seung In KimSook Jin Park Hye Ran YangA Reum Baek In Su KimYoung Hoon Jung 《Tetrahedron》2013
The total synthesis of (+)-valienamine and (−)-1-epi-valienamine was concisely accomplished from readily available d-glucose via a highly diastereoselective amination of chiral benzylic ether using chlorosulfonyl isocyanate, intramolecular olefin metathesis, and diastereoselective reduction of cyclic enone using l-Selectride as the key steps. 相似文献