排序方式: 共有65条查询结果,搜索用时 78 毫秒
41.
Thiago B. Cahú Rodrigo A. Silva Raquel P. F. Silva Milena M. Silva Isabel R. S. Arruda Janilson F. Silva Romero M. P. B. Costa Suzan D. Santos Helena B. Nader Ranilson S. Bezerra 《Applied biochemistry and biotechnology》2017,183(3):765-777
In this work, chitosan-based films containing gelatin and chondroitin-4-sulfate (C4S) with and without ZnO particles were produced and tested in vitro to investigate their potential wound healing properties. Chitosans were produced from shrimp-head processing waste by alkaline deacetylation of chitin to obtain chitosans differing in molecular weight and degree of deacetylation (80 ± 0.5%). The film-forming solutions (chitosan, C4S and gelatin) and ZnO suspension showed no toxicity towards fibroblasts or keratinocytes. Chitosan was able to agglutinate red blood cells, and film-forming solutions induced no hemolysis. Film components were released into solution when incubated in PBS as demonstrated by protein and sugar determination. These data suggest that a stable, chitosan-based film with low toxicity and an ability to release components would be able to establish a biocompatible microenvironment for cell growth. Chitosan-based films significantly increased the percentage of wound healing (wound contraction from 65 to 86%) in skin with full-thickness excision when compared with control (51%), after 6 days. Moreover, histological analysis showed increased granulation tissue in chitosan and chitosan/gelatin/C4S/ZnO films. Chitosan-based biopolymer composites could be used for improved biomedical applications such as wound dressings, giving them enhanced properties. 相似文献
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Dr. Madeleine C. Warner Grigory A. Shevchenko Suzan Jouda Dr. Krisztián Bogár Prof. Jan‐E. Bäckvall 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(41):13859-13864
Dynamic kinetic resolution of various homoallylic alcohols with the use of Candida antarctica lipase B and ruthenium catalyst 2 afforded homoallylic acetates in high yields and with high enantioselectivity. These enantiopure acetates were further transformed into homoallylic acrylates after hydrolysis of the ester function and subsequent DMAP‐catalyzed esterification with acryloyl chloride. After ring‐closing metathesis 5,6‐dihydropyran‐2‐ones were obtained in good yields. Selective hydrogenation of the carbon? carbon double bond afforded the corresponding δ‐lactones without loss of chiral information. 相似文献
43.
Liu P Meagher RJ Light YK Yilmaz S Chakraborty R Arkin AP Hazen TC Singh AK 《Lab on a chip》2011,11(16):2673-2679
We describe an integrated microfluidic device (μFlowFISH) capable of performing 16S rRNA fluorescence in situ hybridization (FISH) followed by flow cytometric detection for identifying bacteria in natural microbial communities. The device was used for detection of species involved in bioremediation of Cr(vi) and other metals in groundwater samples from a highly-contaminated environmental site (Hanford, WA, USA). The μFlowFISH seamlessly integrates two components: a hybridization chamber formed between two photopolymerized membranes, where cells and probes are electrophoretically loaded, incubated and washed, and a downstream cross structure for electrokinetically focusing cells into a single-file flow for flow cytometry analysis. The device is capable of analyzing a wide variety of bacteria including aerobic, facultative and anaerobic bacteria and was initially tested and validated using cultured microbes, including Escherichia coli, as well as two strains isolated from Hanford site: Desulfovibrio vulgaris strain RCH1, and Pseudomonas sp.strain RCH2 that are involved in Cr(vi) reduction and immobilization. Combined labeling and detection efficiencies of 74-97% were observed in experiments with simple mixtures of cultured cells, confirming specific labeling. Results obtained were in excellent agreement with those obtained by conventional flow cytometry confirming the accuracy of μFlowFISH. Finally, the device was used for analyzing water samples collected on different dates from the Hanford site. We were able to monitor the numbers of Pseudomonas sp. with only 100-200 cells loaded into the microchip. The μFlowFISH approach provides an automated platform for quantitative detection of microbial cells from complex samples, and is ideally suited for analysis of precious samples with low cell numbers such as those found at extreme environmental niches, bioremediation sites, and the human microbiome. 相似文献
44.
Artemisia araratica Krasch. is one of the 22 species growing in J. Cullen. In Flora of Turkey and the East Aegean Islands, P.H. Davis (Ed.), Vol. 5, University Press, Edinburgh (1975). In this report we have isolated seven flavonoids from the aerial parts of A. araratica. 相似文献
45.
Suzan Ibrahim Aziz Hany Fakhry Anwar Morsy Ahmed El‐Apasery Mohamed Hilmy Elnagdi 《Journal of heterocyclic chemistry》2007,44(4):877-881
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Optimization of inulinase production by Kluyveromyces marxianus using factorial design 总被引:4,自引:0,他引:4
Factorial design and response surface techniques were used to optimize the culture medium for the production of inulinase
by Kluyveromyces marxianus. Sucrose was used as the carbon source instead of inulin. Initially, a fractional factorial design (25–1) was used in order to determine the most relevant variables for enzyme production. Five parameters were studied (sucrose,
peptone, yeast extract, pH, and K2HPO4), and all were shown to be significant. Sucrose concentration and pH had negative effects on inulinase production, whereas
peptone, yeast extract, and K2HPO4 had positive ones. The pH was shown to be the most significant variable and should be preferentially maintained at 3.5. According
to the results from the first factorial design, sucrose, peptone, and yeast extract concentrations were selected to be utilized
in a full factorial design. The optimum conditions for a higher enzymatic activity were then determined: 14 g/L of sucrose,
10 g/L of yeast extract, 20 g/L of peptone, 1 g/L of K2HPO4. The enzymatic activity in the culture conditions was 127 U/mL, about six times higher than before the optimization. 相似文献
49.
Dead cell and side leakage correction for a lead-scintillating fiber electromagnetic calorimeter
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Cheng Zhang Zu-Hao Li Zhi-Cheng Tang Suzan Basegmez du Pree Shao-Wen Zhang Xue-Qiang Wang Min Yang Guo-Ming Chen He-Sheng Chen 《中国物理C(英文版)》2016,40(9):096204-096204
The electromagnetic calorimeter(ECAL) of the Alpha Magnetic Spectrometer(AMS-02) is one of the key detectors for dark matter searches. It measures the energies of electrons, positrons and photons and seperates them from hadrons. Currently, there are 5 dead cells in the ECAL, which affect the reconstructed energy of 4.2%of total events in the ECAL acceptance. When an electromagnetic shower axis is close to the ECAL border, due to the side leakage, the reconstructed energy is affected as well. In this paper, methods for dead cells and side leakage corrections for the ECAL energy reconstruction are presented. For events with the shower axis crossing dead cells,applying dead cell correction improves the difference in the reconstructed energy from 12% to 1%, while for events near the ECAL border, with side leakage correction it is improved from 4% to 1%. 相似文献
50.
Mohammad Alhilal Yaser A. M. Sulaiman Suzan Alhilal Sobhi M. Gomha Salama A. Ouf 《Molecules (Basel, Switzerland)》2021,26(5)
This paper aimed to investigate the potential antifungal influences of new alkaloids from Delphinium peregrinum L. var. eriocarpum Boiss. New Diterpenoid alkaloids Delcarpum (1), Hydrodavisine (4) and known alkaloids Peregrine (2), Delphitisine (3) were isolated by different chromatographic methods from the aerial parts of D. Peregrinum eriocarpum Boiss, which grows in Syria. The structures of alkaloids were proposed based on 1D NMR spectroscopy 1H-NMR, 13C-NMR, DEPT-135, DEPT-90, 2D NMR spectroscopy DQF-COSY, HMQC, EI-Ms mass spectrum, and IR spectroscopic measurements. The antifungal activity of the isolated alkaloids was evaluated against different dermatophyte fungal isolates compared with fluconazole. In the case of Peregrine (2) the minimum inhibitory concentrations(MICs) recorded 128–256, 32–64, and 32 for Epidermophyton floccosum, Microsporum canis, and Trichophyton rubrum, respectively, compared to 32–64, 16, and 32 μg/mL in the case of fluconazole, respectively. The MICs recorded on application of the four alkaloids mixture were 64, 32, and 16 in the case of E. floccosum, M. canis, and T. rubrum, respectively, which were significantly lower than that measured for each of the individual alkaloid and were compatible for fluconazole. In conclusion, MICs of the tested alkaloids showed a variable potential effect on the investigated fungal isolates. Peregrine (2) was the most effective alkaloid, however, the application of the mixture of alkaloids induced significant synergistic activity that was more pronounced than the application of individual ones. 相似文献