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991.
992.
本实验从黑豆中分离得到两种糖蛋白,并对其结构组成、抗氧化活性和免疫活性进行研究,为糖蛋白的高效开发利用提供理论依据。采用碱提醇沉法提取黑豆糖蛋白粗品,命名为HDJ,通过DEAE-52纤维素柱层析和Sephadex G-100柱层析分离纯化获得两个均一组分,分别命名为HDJS2和HDJS5-2。利用物理化学方法和光谱法对其化学组成及结构进行分析,通过测定总还原力、1,1-二苯基-2-三硝基苯肼(2,2-diphenyl-1-picrylhydrazyl,DPPH)清除率及总抗氧化能力研究两种糖蛋白的抗氧化活性,采用噻唑蓝比色法评价两种糖蛋白的免疫活性。结果表明:HDJS2(3.20×104 Da)和HDJS5-2(3.89×104 Da)主要是由中性糖和蛋白质组成的糖蛋白,其糖肽键类型均为O-型糖肽键。HDJS2主要由甘露糖、葡萄糖、半乳糖、阿拉伯糖、岩藻糖和96.1%氨基酸组成;HDJS5-2主要由甘露糖、葡萄糖、半乳糖、阿拉伯糖和71.3%氨基酸组成。抗氧化分析结果表明,HDJS2和HDJS5-2的还原能力、DPPH清除能力和抗氧化能力呈剂量依赖性关系。此外,HDJS2和HDJS5-2均能够促进脾淋巴细胞增殖。结论:HDJS2和HDJS5-2具有潜在的抗氧化作用和免疫调节作用。 相似文献
993.
994.
Site-specific seismic hazard analysis is crucial for designing earthquake resistance structures, particularly in seismically active regions. Shear wave velocity ( V S) is a key parameter in such analysis, although the economy and other factors restrict its direct field measurement in many cases. Various V S–SPT– N correlations are routinely incorporated in seismic hazard analysis to estimate the value of V S. However, many uncertainties question the reliability of these estimated V S values. This paper comes up with a statistical approach to take care of such uncertainties involved in V S calculations. The measured SPT– N values from all the critical boreholes were converted into statistical parameters and passed through various correlations to estimate V S at different depths. The effect of different soil layers in the boreholes on the Vs estimation was also taken into account. Further, the average shear wave velocity of the top 30 m soil cover ( V S30) is estimated after accounting for various epistemic and aleatoric uncertainties. The scattering nature of the V S values estimated using different V S– N correlations was reduced significantly with the application of the methodology. Study results further clearly demonstrated the potential of the approach to eliminate various uncertainties involved in the estimation of V S30 using general and soil-specific correlations. 相似文献
995.
在统计2012—2019年期间A煤矿事故数据的基础上,结合事故人员年龄、事故类型、伤情类别等研究了该煤矿事故的发生规律,并针对煤矿易发生的事故,本着预防为主、降低事故损失的原则,从安全管理、重点防控对象、应急处置能力提升方面提出了对策。 相似文献
996.
997.
Fang Wang Shukun Le Fanyue Song Yiguo Su 《International Journal of Hydrogen Energy》2021,46(2):2103-2116
The appropriate interfacial contact and charges transfer mode of heterojunction photocatalysts were critical for high-efficiency hydrogen production. Inter-step mode heterojunction composite had advantages of enhanced visible-light response, improved charge space separation rate, increased electron utilization, which could also protect catalyst anode from photocorrosion. Zinc-vacancy-rich ZnS decorated CdS heterojunction photocatalyst with inter-step mode was constructed in order to fundamentally enhance photocatalytic performance and overcome photocorrosion of CdS. The charge transfer mode was modulated from pervasive type-II to bran-new inter-step mode by defect engineering. Zinc vacancies functioned as acceptor level for charge separation and up-shifted conduction and valance band energy of ZnS. The defective engineered CdS/ZnS heterojunction displayed a reduced over-potential and enhanced photocatalytic activity. The optimal photocatalytic hydrogen production rate for CdS/ZnS reached 42.1 mmol?g?1 under visible light without any co-catalyst. An apparent quantum yield (AQY) of 38.75% at 450 nm was achieved, which was 269.3 and 71.9 times higher than pristine zinc-vacancy-rich ZnS and CdS, respectively. Meanwhile, holes aggregated on the surface of CdS were blocked and the oxidation corrosion process was suppressed. The charge transfer mechanism and kinetics of charge transfer and separation in inter-step mode heterojunction photocatalysts were investigated and discussed. This work will accelerate practical applications of photocatalysis with inter-step mode and give deep insights into understanding how inherent acceptor levels play a role in designing defect-engineered semiconductor with enhanced photocatalytic performance. 相似文献
998.
Siti Norhamimah Mohamed Yunus Faridah Abas Ahmad Haniff Jaafar Awanis Azizan Nur Khaleeda Zulaikha Zolkeflee Siti Zulaikha Abd Ghafar 《Food science and biotechnology》2021,30(2):195
The 70% ethanolic extracts from eight neglected fruits; Muntingia calabura, Leucaena leucocephala, Spondias dulcis, Syzygium jambos, Mangifera caesia, Ardisia elliptica, Cynometra cauliflora and Ficus auriculata were evaluated for their 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging, α-glucosidase inhibitory activities as well as total phenolic content. The results of this study revealed that M. caesia fruit extract demonstrated the most potent radical scavenging activity. Among the fruits examined for α-glucosidase inhibitory activity, M. calabura and F. auriculata exhibited strong activity with no significant difference. The Pearson correlation indicated that the activities of M. caesia and F. auriculata contributed by phenolic compounds. A total of 65 metabolites were tentatively identified by using ultra-high-performance liquid chromatography tandem mass spectrometry (UHLPC-MS/MS). These findings suggested that the possible application of M. caesia and F. auriculata as a functional food with antioxidant and α-glucosidase inhibitory properties. 相似文献
999.
邵啸 《皮革制作与环保科技》2021,(5):146-147
危险废物具有各种危害性,不仅对人体健康有着威胁,对于环境治理来说也有着极大的消极影响。就目前来说,虽然安全填埋技术已经较为成熟,但在实际实施过程中还是容易出现渗漏事故,渗漏液在地下容易穿透防渗层,从而影响地下水,所以这也是我们需要重视的问题之一。 相似文献
1000.