不同比表面积煤气化渣掺合料活性及力学性能研究

煤气化渣是煤气化、煤间接液化工艺的副产物.本文对不同粉磨时间的煤气化渣理化性能、活性、力学性能等进行了研究,并和常用的S95矿粉和I级粉煤灰进行对比.研究表明,煤气化渣本身含有大量的非晶态胶凝活性物质,比表面积为503 m2/kg的煤气化渣活性达到108％,高于I级粉煤灰.煤气化渣的掺加能够显著提升水泥砂浆的后期强度,最大可提高47.2％,提升作用优于S95矿粉和I级粉煤灰.煤气化渣对抗折强度的提高率大于抗压强度,在20％ ～30％(质量分数)掺量下能够提高水泥砂浆的柔韧性.     

抗运动疲劳食源性活性成分的研究进展

本文对近些年来研究发现的抗运动疲劳的食源性活性成分及其在抗运动疲劳产品开发中的运用情况进行了综述,以期以能量代谢和抗氧化的共同调控靶点为基础,进一步对抗运动疲劳食源活性成分精选及研发天然食源性活性成分的特色抗运动疲劳食品提供理论依据。     

南鹤虱化学成分和药理活性研究进展

南鹤虱作为中药药材历史悠久,其化学成分主要含有挥发油、萜类、黄酮类、香豆素类、甾体类以及蛋白质等。研究表明,其具有杀虫、抗菌、抗癌、抗生育性、改善认知功能障碍、修复肝脏损伤等多种生物活性。通过对国内外南鹤虱相关文献资料进行系统化梳理,对其化学成分和药理活性进行总结,以期为南鹤虱的进一步研究、开发和应用提供参考。     

大鼠肠囊外翻法分析核桃肽吸收特性及抗氧化肽筛选鉴定

本研究通过大鼠肠囊外翻法探讨了<3 kDa核桃蛋白肽模拟胃肠消化产物的吸收特性,以抗氧化能力(DPPH自由基清除率、ABTS⁺自由基清除率、Fe²⁺螯合率)和活性肽吸收率为指标筛选核桃肽在肠道吸收的最优条件,并应用模拟分子对接技术和Nano-HPLC-MS/MS技术对吸收肽组分进行筛选和鉴定,得到能够以完整形式被吸收并发挥抗氧化活性的新型核桃源肽。结果表明:当核桃肽消化产物吸收浓度为6 mg/mL,吸收时间为2 h时,其抗氧化活性最高且在小肠吸收率最高:进一步通过Nano-HPLC-MS/MS鉴定结果表明0.5～1 kDa活性肽数量最多,其中位于C端/N端氨基酸主要集中在Pro、Thr、Leu,鉴定出33条活性肽能够以完整形式被吸收,穿过肠道屏障;最后通过分子对接技术与DPP-Ⅳ相结合,获得三条结合能最低的活性肽NLRFPL、NPDDEFRPQ、KGHLFPN,其结合能分别为-8.8、-8.6、-8.6 kal/mol,其中KGHLFPN抗氧化能力最强。综上,<3 kDa核桃肽模拟胃肠道消化能够释放抗氧化活性更高且能够被小肠吸收的...     

Research progress on chemical modification of silk fibroin and its applications北大核心CSCD

Mulberry silk is composed of the two major parts of two triangle-like silk fibroin fibers and sericin covering the fibers and a few lipids. After removing the sericin on the raw silk what is left is the silk fibroin fiber. Silk fibroin is the main part of silk accounting for about 75% of the total weight. Silk fibroin contains 18 natural amino acids such as glycine Gly alanine Ala serine Ser serine aspartic acid Asp and tyrosine Tyr . The secondary structure of silk fibroin has three main conformations α-helix β-fold and random coil. Under certain conditions the three conformations can transform into each other and change the mechanical properties of the silk fibroin material. Silk fibroin extracted from silk fiber is a natural polymer with biocompatibility and biodegradability. It can be further processed into different forms of materials nanoparticles films hydrogels sponges etc. It has been applied in many fields such as biomedicine and cosmetics. In order to meet the needs of different fields researchers have conducted further chemical modification treatment based on the original excellent properties of silk fibroin. Meanwhile the active groups on various amino acid residues in silk fibroin also provide chemical reaction sites for the chemical modification of silk fibroin. The chemical modification methods of silk fibroin mainly include amino acid residue modification macromolecular grafting modification and crosslinking reaction modification. Among them amino acid residue modification can modify protein amino acid residues by chemical reagents and some groups can be introduced into the side chains of silk fibroin macromolecules. Grafting modification of silk fibroin macromolecules is one of the main means to bind functional compounds to silk fibroin macromolecular chains. The properties of grafted silk fibroin are affected by the type and grafting rate of the grafts. The chemical crosslinking reaction modification of silk fibroin macromolecules is to make the macromolecular chains connected by covalent bonds and form a network structure by means of crosslinking agents enzymes or ultraviolet irradiation. The cross-linking reaction can not only form covalent bonds within and between the molecular chains of silk fibroin thus changing its structural properties and improving its stability but be used to form covalent bonds with other polymers. At present the chemical modification of silk fibroin is mainly applied in the fields of silk textiles biomedicine and environmental science. In the field of silk textiles graft copolymerization modification of vinyl and other monomers crosslinking agent modification and other methods are used to overcome the shortcomings of silk like being easy to wrinkle. The graft modified monomers mainly include ethylene methacrylate and methylacrylamide. The active groups on crosslinking agents such as polycarboxylic acid / anhydride and epoxide are covalently combined with carboxyl hydroxyl and amino groups on macromolecules of silk fibroin to improve the wrinkle resistance of silk fabrics. In the field of biomedicine silk fibroin materials with appropriate chemical modification have better biological activity drug delivery ability antimicrobial properties and mechanical properties. The optimization of these properties enables silk fibroin materials to show great potential in drug control delivery tissue regeneration and wound repair. The applied research in the field of environmental science mainly focuses on the adsorption separation and catalysis of impurities in water. Therefore the modification of amino acid residues grafting and cross-linking of protein macromolecules can change some important properties of silk fibroin and meet the requirements of various applications and functionalization of silk fibroin. In many fields of chemical modification and application of silk fibroin protein fruitful results have been achieved which has laid a good foundation for the further development of related fields and also shows that the chemical modification of silk fibroin material has great potential and application prospects. However there are still some problems that need to be overcome and further improved in the current chemical modification methods such as mild modification conditions and accurate adjustment of the degree of modification which will be the research direction of related fields in the future. © 2022 Authors. All rights reserved.     

金属离子和食品添加剂对六氢β-酸/甲基-β-环糊精包合物的抑菌活性影响

论文采用二倍稀释法确定了六氢β-酸环糊精包合物对7种测试菌种的最小抑菌浓度，并以活性较强的金黄色葡萄球菌和阪崎肠杆菌为指示菌，研究金属离子、食品添加剂对其抑菌活性的影响。结果表明，六氢β-酸环糊精包合物具有广谱抑菌性，除了对乙型副伤寒沙门氏菌无抑菌效果，对其他测试菌种均有良好的抑菌活性，对金黄色葡萄球菌和阪崎肠杆菌的MIC分别为16.25 μg/mL和32.5 μg/mL。金属离子Ca2 、K 、Na 、Mg2 、Zn2 对包合物的抑菌活性没有明显影响，Fe2 /3 、Cu2 对包合物的抑菌活性影响较明显。食品添加剂中NaNO2、苯甲酸钠对其抑菌活性没有明显影响，Na2SO3会略微增大对阪崎肠杆菌的抑菌活性，山梨酸钾在高浓度会降低其对阪崎肠杆菌的抑菌活性，H2O2、KMnO4在高浓度时均会明显降低其活性。     

多种金属离子改性的TiO_2催化剂的制备及光催化活性研究

不存在毒副作用、化学稳定性较高、光催化活性较强、使用安全程度高及成本低是二氧化钛的几大优势,其作为半导体材料得到了广泛的研究。将钴、锡、钨和二氧化钛复合制备了复合催化剂,用于罗丹明B的光催化降解,取得了良好的催化效果。