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991.
Electrical stimulation (ES) within a conductive scaffold is potentially beneficial in encouraging the differentiation of stem cells toward a neuronal phenotype. To improve stem cell-based regenerative therapies, it is essential to use electroconductive scaffolds with appropriate stiffnesses to regulate the amount and location of ES delivery. Herein, biodegradable electroconductive substrates with different stiffnesses are fabricated from chitosan-grafted-polyaniline (CS-g-PANI) copolymers. Human mesenchymal stem cells (hMSCs) cultured on soft conductive scaffolds show a morphological change with significant filopodial elongation after electrically stimulated culture along with upregulation of neuronal markers and downregulation of glial markers. Compared to stiff conductive scaffolds and non-conductive CS scaffolds, soft conductive CS-g-PANI scaffolds promote increased expression of microtubule-associated protein 2 (MAP2) and neurofilament heavy chain (NF-H) after application of ES. At the same time, there is a decrease in the expression of the glial markers glial fibrillary acidic protein (GFAP) and vimentin after ES. Furthermore, the elevation of intracellular calcium [Ca2+] during spontaneous, cell-generated Ca2+ transients further suggests that electric field stimulation of hMSCs cultured on conductive substrates can promote a neural-like phenotype. The findings suggest that the combination of the soft conductive CS-g-PANI substrate and ES is a promising new tool for enhancing neuronal tissue engineering outcomes. 相似文献
992.
Mubashir Hussain Zhen Chen Mu Lv Jingyi Xu Xiaohan Dong Jingzhou Zhao Song Li Yan Deng Nongyue He Zhiyang Li Bin Liu 《中国化学快报》2021,31(12):3163-3167
The rapid identification of pathogens is crucial in controlling the food quality and safety. The proposed system for the rapid and label-free identification of pathogens is based on the principle of laser scattering from the bacterial microbes. The clinical prototype consists of three parts: the laser beam, photodetectors, and the data acquisition system. The bacterial testing sample was mixed with 10 mL distilled water and placed inside the machine chamber. When the bacterial microbes pass by the laser beam, the scattering of light occurs due to variation in size, shape, and morphology. Due to this reason, different types of pathogens show their unique light scattering patterns. The photo-detectors were arranged at the surroundings of the sample at different angles to collect the scattered light. The photodetectors convert the scattered light intensity into a voltage waveform. The waveform features were acquired by using the power spectral characteristics, and the dimensionality of extracted features was reduced by applying minimal-redundancy-maximal-relevance criterion (mRMR). A support vector machine (SVM) classifier was developed by training the selected power spectral features for the classification of three different bacterial microbes. The resulting average identification accuracies of E. faecalis,E. coli and S. aureus were 99%, 87%, and 94%, respectively. The overall experimental results yield a higher accuracy of 93.6%, indicating that the proposed device has the potential for label-free identification of pathogens with simplicity, rapidity, and cost-effectiveness. 相似文献
993.
Jie Xu Weihua Qiu Xu Zhang Zhihan Wu Zhen Zhang Dr. Kai Yang Prof. Dr. Qiuling Song 《Angewandte Chemie (International ed. in English)》2023,62(47):e202313388
The direct C−H functionalization of 1,2-benzazaborines, especially asymmetric version, remains a great challenge. Here we report a palladium-catalyzed enantioselective C−H olefination and allylation reactions of 1,2-benzazaborines. This asymmetric approach is a kinetic resolution (KR), providing various C−B axially chiral 2-aryl-1,2-benzazaborines and 3-substituted 2-aryl-1,2-benzazaborines in generally high yields with excellent enantioselectivities (selectivity (S) factor up to 354). The synthetic potential of this reaction is showcased by late-stage modification of complex molecules, scale-up reaction, and applications. 相似文献
994.
Small molecular biothiols, cysteine (Cys), homocysteine (Hcy) and glutathione (GSH), play important roles in organisms, and their concentration levels are indicative of some human diseases. Herein we report an organic dye-conjugated β-diketonate-Eu3+ complex, [Eu(NBD-keto)3(DPBT)] (NBD-keto: 7-nitro-2,1,3-benzoxadiazole (NBD)-conjugated to 1,1,1,2,2-pentafluoro-5-phenyl-3,5-pentanedionate through a “O” ether bond; DPBT: 2-(N,N-diethylanilin-4-yl)-4,6-bis(3,5-dimethylpyrazol-1-yl)-1,3,5-triazine), which acts as a unique luminescent probe for detecting and discriminating biothiols. [Eu(NBD-keto)3(DPBT)] itself is not luminescent due to intramolecular interactions between NBD and β-diketonate-Eu3+ moieties. Upon reaction with biothiols, the β-diketonate-Eu3+ complex [Eu(keto)3(DPBT)] is generated, which emits long-lived red emission at 610 nm. Meanwhile, three biothiol-substituted NBD derivatives that exhibit different luminescence behaviors, green emissive (short-lived) NBD-NR (R=Cys or Hcy) at 540 nm and non-luminescent NBD-SR (R=GSH), are also generated. These luminescence response behaviors allow time-gated and steady-state luminescence modes to be combined for detecting total biothiols and discriminating GSH and Cys/Hcy. Using this probe, the quantitative detection and discrimination of GSH and Cys/Hcy in lysis solutions of HeLa cells were realized, which revealed the potential of the probe for biomedical applications. 相似文献
995.
低成本、高性能的钠离子电池有望成为代替锂离子电池的下一代核心器件.但是开发出高比容量、高倍率的钠离子电池负极材料依然是瓶颈.本文通过水热/溶剂热法制备了Co基前驱体,然后将其一步硫/磷热处理制得具有空心多孔结构的h-Co9S8/CoP/C纳米复合材料.通过X-射线粉末衍射(XRD)、拉曼光谱(Raman)、扫描电镜(SEM)、透射电镜(TEM)和X-射线光电子能谱(XPS)等表征以确定纳米复合物的物相以及形貌特征.当h-Co9S8/CoP/C作为钠离子电池负极材料时,该电极材料展示了高的比容量(561 mAh g-1@0.1 Ag-1)、较好的循环性能(可逆比容量200 mAh g-1@2 Ag-1)和倍率性能.h-Co9S8/CoP/C之所以显示出良好的储钠性能,主要得益于其空心多孔结构不仅提供更多的空间缓解钠在反复嵌入和脱出过程造成的体积膨胀效应,而且可以缩短离子/电荷扩散途径以加快反应动力学,此外,Co9S8、CoP和C独特的电子结构优势得以共同发挥. 相似文献
996.
997.
聚氯乙烯/线性低密度聚乙烯共混体系的相容性 总被引:5,自引:0,他引:5
用动态力学分析(DMA)和傅利叶变换红外光谱(FTIR)研究了氢化聚丁二烯-b-聚甲基丙烯酸甲酯(HPBD-b-PMMA)共聚物增容剂对聚氯乙烯(PVC)与线性低密度聚乙烯(LLDPE)共混体系的增容作用.增容剂使共混物中两相的玻璃化温度发生变化,说明其相容性增加.FTIR的结果表明,增容剂中羰基与PVC的α氢形成氢键,使CO,H─C及C─Cl的振动频率变化,峰形加宽. 相似文献
998.
用离子抑制色谱法分析二(2,2,6,6—四甲基—4—哌啶基)马来酸酯合?… 总被引:4,自引:0,他引:4
建立了用离子抑制色谱法分析二(2,2,6,6-四甲基-4-哌啶基)马来酸酯合成反应液的方法。平均回收率为98.8%,相对标准偏差为0.56%,测量的平均相对偏差不大于5.0%,方法简单,快速,可用于工艺条件的选择和质量检测。 相似文献
999.
钌联吡啶络合物与脱氧核糖核酸分子相互作用的荧光光谱研究与分析应用 总被引:1,自引:0,他引:1
合成了2苯基(4溴)咪唑[f]邻菲咯啉(简称PIP(Ⅲ)新的配体及〔Ru(bpy)_2PIP(Ⅲ)]~(2+)新的络合物,用荧光光谱研究了络合物与小牛胸腺DNA分子的结合情况,在 pH7.4,络合物与DNA作用后,在587nm(λ_(ex)=471nm)产生很强的荧光峰,其发光强度与DNA浓度呈线性关系;线性范围0~1.2mg/L;检测限(3a(?))为2.8mg/L.该方法具有较高灵敏度和准确度,对合成样品测定,结果令人满意. 相似文献
1000.
心脑血管疾病与微量元素研究进展 总被引:3,自引:2,他引:3
心脑血管疾病发病日益增多的原因之一是机体缺乏人体必需微量元素,目前报道硒、锗、锌、钴、铜、锰、铬、钼、钒、镍等与心脑血管疾病有密切关系。用微量元素调控防治心脑血管疾病,目前是国内外研究的新课题,其目的是降低心脑血管疾病的死亡率和发病率,促进人类健康长寿。 相似文献