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排序方式: 共有213条查询结果,搜索用时 15 毫秒
21.
Shouqun Jiang Zongyong Jiang Tianxing Wu Xianyong Ma Chuntian Zheng Shutong Zou 《Food chemistry》2007,105(3):1086-1090
The antioxidant and protective properties of a synthetic soybean isoflavone (SI) were investigated using chick skeletal (leg) muscle cells (SMC) isolated from 20-day-old Linnan yellow broiler chick embryo. Skeletal muscle cells were cultured in Dulbecco’s modified Eagle’s medium treated with 0, 12.5, 25, 50, 75 and 100 μM SI, respectively, under 80 μM H2O2/FeSO4 conditions. After 24 h of incubation, SI reduced the loss of SMC under oxidative stress by H2O2/FeSO4. The addition of SI significantly promoted SMC proliferation (P < 0.01). Upon treatment with 25, 50, 75 and 100 μM SI, the activity of total superoxide dismutase in the supernatant of the media was enhanced by 17.0%, 13.0%, 13.3% and 11.9%, respectively (P < 0.05). Compared to the control, the activity of glutathione peroxidase was significantly increased only at 25 μM concentration of SI (P < 0.05), and the increment was 90.7%. The activity of catalase was increased by 49.2% and 49.1%, respectively, at 75 and 100 μM SI (P < 0.01). The concentration of creatine kinase in the media was decreased by 61.6% and 60.6%, respectively, at 75 and 100 μM SI (P < 0.01). The addition of SI did not affect the activity of lactate dehydrogenase in the media. In conclusion, the SI protected skeletal muscle cells from oxidative damage, attributed to its antioxidant activity. 相似文献
22.
The thermal and mechanical properties of UV curing coatings consisted of urethane acrylates as an oligomer and a diacrylate monomer were reinforced by using layered double hydroxide (LDH). The LDH was organically modified by an ion-exchange process, in which the nitrate anions were replaced by long alkyl sulfate anions. With organic modification, the d-spacing of inorganic LDH layers was greatly enlarged to 2.75 from 0.78 nm, leading the LDH to be organophilic. During in situ photopolymerization process, the d-spacing of LDH layers was further enlarged to 4.29 nm, indicating the intercalation of polymer chains. For comparison, polymer/LDH nanocomposite filled with un-modified LDH was also prepared, and showed less enhancement in thermal and mechanical properties. 相似文献
23.
24.
Martina Rudnicki Marcos Roberto de Oliveira Tiago da Veiga Pereira Flávio Henrique Reginatto Felipe Dal-Pizzol José Cláudio Fonseca Moreira 《Food chemistry》2007,100(2):719-724
The leaves of Passiflora alata Dryander and Passiflora edulis Sims, traditionally used in American countries to treat both anxiety and nervousness by folk medicine, are rich in polyphenols, which have been reported as natural antioxidants. In this study, the antioxidant activities of P. edulis and P. alata hydroalcoholic leaf extracts were verified in in vitro and ex vivo assays. P. alata showed a higher total reactive antioxidant potential than did P. edulis. The antioxidant activities of both extracts were significantly correlated with polyphenol contents. In addition, both extracts attenuated ex vivo iron-induced cell death, quantified by lactate dehydrogenase leakage, and effectively protected against protein damage induced by iron and glucose. These findings demonstrate that the P. alata and P. edulis leaf extracts have potent in vitro and ex vivo antioxidant properties and might be considered as possible new sources of natural antioxidants. 相似文献
25.
Farahnaz Barahuie Mohd Zobir Hussein Sharida Fakurazi Zulkarnain Zainal 《International journal of molecular sciences》2014,15(5):7750-7786
Layered hydroxides (LHs) have recently fascinated researchers due to their wide application in various fields. These inorganic nanoparticles, with excellent features as nanocarriers in drug delivery systems, have the potential to play an important role in healthcare. Owing to their outstanding ion-exchange capacity, many organic pharmaceutical drugs have been intercalated into the interlayer galleries of LHs and, consequently, novel nanodrugs or smart drugs may revolutionize in the treatment of diseases. Layered hydroxides, as green nanoreservoirs with sustained drug release and cell targeting properties hold great promise of improving health and prolonging life. 相似文献
26.
Jae Woong Han Sangiliyandi Gurunathan Jae-Kyo Jeong Yun-Jung Choi Deug-Nam Kwon Jin-Ki Park Jin-Hoi Kim 《Nanoscale research letters》2014,9(1):459
The goal of the present study was to investigate the toxicity of biologically prepared small size of silver nanoparticles in human lung epithelial adenocarcinoma cells A549. Herein, we describe a facile method for the synthesis of silver nanoparticles by treating the supernatant from a culture of Escherichia coli with silver nitrate. The formation of silver nanoparticles was characterized using various analytical techniques. The results from UV-visible (UV-vis) spectroscopy and X-ray diffraction analysis show a characteristic strong resonance centered at 420 nm and a single crystalline nature, respectively. Fourier transform infrared spectroscopy confirmed the possible bio-molecules responsible for the reduction of silver from silver nitrate into nanoparticles. The particle size analyzer and transmission electron microscopy results suggest that silver nanoparticles are spherical in shape with an average diameter of 15 nm. The results derived from in vitro studies showed a concentration-dependent decrease in cell viability when A549 cells were exposed to silver nanoparticles. This decrease in cell viability corresponded to increased leakage of lactate dehydrogenase (LDH), increased intracellular reactive oxygen species generation (ROS), and decreased mitochondrial transmembrane potential (MTP). Furthermore, uptake and intracellular localization of silver nanoparticles were observed and were accompanied by accumulation of autophagosomes and autolysosomes in A549 cells. The results indicate that silver nanoparticles play a significant role in apoptosis. Interestingly, biologically synthesized silver nanoparticles showed more potent cytotoxicity at the concentrations tested compared to that shown by chemically synthesized silver nanoparticles. Therefore, our results demonstrated that human lung epithelial A549 cells could provide a valuable model to assess the cytotoxicity of silver nanoparticles. 相似文献
27.
Qiuhua Chen Shuxian Shi Xiaolei Liu Lan Jin Min Wei 《Chemical engineering journal (Lausanne, Switzerland : 1996)》2009,153(1-3):175-182
The amino acid l-cysteine (l-Cys) was intercalated into a MgAl layered double hydroxide (LDH), and its oxidation reaction by hexacyanoferrate (III) (Fe(CN)63−) in the confined region between sheets of LDH has been studied in detail. Based on the measurement results of XRD, Raman and FT-IR, it was found that the interlayer l-Cys was oxidized to cystine by Fe(CN)63−. Furthermore, the kinetics of this reaction was investigated in batch mode. The influences of initial Fe(CN)63−concentration, l-Cys-LDH quantity and reaction temperature on the interlayer oxidation reaction have been studied, respectively. The reaction follows a diffusion-controlled mechanism represented by Crank-Ginstling and Brounshtein kinetic model with the apparent activation energy of 29.93 kJ/mol. Therefore, this layered material may have prospective application as a novel “molecular reactor” for confined chemical reactions. 相似文献
28.
Isabel Sánchez Mario Ramírez Marina Casas Angulo Raquel Vigil de la Villa Rosario García-Giménez Oscar Bomati Antonio Zapardiel 《Journal of the American Ceramic Society》2019,102(8):4990-4998
Reutilization of industrial waste products as cement additives yields a number of secondary materials, yet their identification is not always trivial. Confirmation of the formation of a LDH-type (phyllosilicate/carbonate) material is the main purpose of this study. Mineralogically, organic and inorganic compounds form some industrial wastes, among which the phyllosilicates are prominent. Crystalline and amorphous hydrated phases appeared during the pozzolanic reaction in a dehydroxylated phyllosilicate/lime system, whose controlled activation yielded dehydroxylated products with high pozzolanic properties. The LDH-type (phyllosilicate/carbonate) material was one of the reaction products; this material could be considered as the superposition type 1:1 of tetrahedral layers of silicon and aluminum and octahedral layers of aluminum (dehydroxylated kaolinite), generating a positive charge in the interlaminar region compensated by carbonate anions with a basal spacing (001) measured by XRD at 7.57Å. Therefore, several techniques were used to determine whether they could be included in the structural group named Layered Double Hydroxides (LDHs), as they are, too, laminar layers of oxides and hydroxides with a positive laminar charge in the interlayer region compensated by the presence of anions with similar basal spacing. In this research, the effects of activation temperature and calcite proportion were analyzed on the hydrated phases formed after 28 days of pozzolanic reaction in a metakaolin (MK)/lime system. The MK was obtained from a mix of 1:1; 2:1 and 3:1 kaolinite:calcite mixture, thermally activated at 750°C for 2 hours, comparing it with kaolinite activated at 600°C for 2 hours. As the most LDH-rich sample, the 1:1 LDH-type (phyllosilicate/carbonate) phase was characterized using XRD, SEM-EDX, HRTEM-EDX, FTIR, NMR-MAS, and Raman spectroscopy. 相似文献
29.
通过共沉淀法制备了锌铝水滑石(ZnAl-LDH),采用XRD、FTIR、SEM对其结构进行了表征.将其配合用量为皮质量2%的铬粉(记为2%铬粉)应用于制革鞣制工艺中.考察了ZnAl-LDH制备时的金属源物质的量比、陈化时间对鞣制坯革收缩温度、鞣后废液中的Cr2O3质量浓度的影响.结果表明,ZnAl-LDH是尺寸在100~400 nm之间的片状材料.当n〔(Zn(NO3)2?6H2O)〕:n〔Al(NO3)3?9H2O〕=2.0:1.0,陈化时间为6 h时,制备的ZnAl-LDH-4具有优异的性能.与单独使用2%铬粉鞣制坯革相比,ZnAl-LDH-4(用量为皮质量的4%)配合2%铬粉鞣制坯革收缩温度由75℃提高到94℃,废液中的Cr2O3质量浓度由99.58 mg/L降低至46.98 mg/L,且加入ZnAl-LDH-4鞣制后,鞣后废液化学需氧量和生物需氧量均降低. 相似文献
30.
Mauro Zammarano Séverine Bellayer Jeffrey W. Gilman Frederick L. Beyer Sergio Meriani 《Polymer》2006,47(2):652-662
Layered double hydroxides (LDH) are a class of readily synthesizable layered crystals that can be used as an alternative to the commonly used silicate crystals for the preparation of polymeric nanocomposites. In this work layered double hydroxide/polyamide 6 nanocomposites (LDH/PA6) were prepared from organo-modified LDH by melt processing. The anionic exchange capacity of LDH was varied in order to investigate its influence on the degree of exfoliation. LDH were dispersed by a twin screw micro-extruder at a variety of processing conditions. The nanocomposites were characterized by wide-angle X-ray diffraction (WAXD), small-angle X-ray scattering (SAXS), transmission electron microscopy, dynamic scanning calorimetry, and thermogravimetric analysis. It was found that exfoliated nanocomposites were successfully prepared by melt processing with a low exchange capacity LDH, whereas residue tactoids were observed with a high exchange capacity LDH. Shear, together with the exchange capacity, seems to be the key factor for the delamination in LDH/PA6. No major change in the crystalline phase or in the rate of crystallization was observed in the nanocomposite as compared to the neat polymer. A reduction in the onset of thermal decomposition temperature was observed in PA6/LDH compared to neat PA6, likely due to a nucleophilic attack mechanism. The properties of this nanocomposite system are discussed with connections to the current understanding within the broader nanocomposite field. 相似文献