聚乳酸多元醇的制备研究

聚乳酸多元醇是合成可降解聚氨酯材料的关键软段原料.分别以1,6-己二醇与三羟甲基丙烷为链转移剂,在Sn(Oct)2的作用下使L-丙交酯开环共聚,成功制备出3种聚乳酸多元醇低聚物.通过1H NMR、FT-IR及GPC表征,表明:聚合物的结构与预期设计的吻合;相对分子质量分别为1 202、1 065、1 613; PDI分别为:1. 17、1. 12、1. 17,相对分子质量分布较窄.     

氯化亚锡作为还原剂在废旧锂离子电池有价金属浸出回收中的应用研究

The reductant is a critical factor in the hydrometallurgical recycling of valuable metals from spent lithium-ion batteries (LIBs). There is limited information regarding the use of SnCl₂ as a reductant with organic acid (maleic acid) for recovering valuable metals from spent LiCoO₂ material. In this study, the leaching efficiencies of Li and Co with 1 mol·L?1 of maleic acid and 0.3 mol·L?1 of SnCl₂ were found to be 98.67% and 97.5%, respectively, at 60°C and a reaction time of 40 min. We investigated the kinetics and thermodynamics of the leaching process in this study to better understand the mechanism of the leaching process. Based on a comparison with H₂O₂ with respect to leaching efficiency, the optimal leaching parameters, and the activation energy, we determined that it is feasible to replace H₂O₂ with SnCl₂ as a leaching reductant in the leaching process. In addition, when SnCl₂ is used in the acid-leaching process, Sn residue in the leachate may have a positive effect on the re-synthesis of nickel-rich cathode materials. Therefore, the results of this study provide a potential direction for the selection of reductants in the hydrometallurgical recovery of valuable metals from spent LIBs.     

纤维素纳米晶对胶凝复合材料耐酸性能的影响

Acid mine drainage presents an important threat to cementitious structures. This study is aimed at investigating the effect of cellulose nanocrystals (CNCs) on the acid resistance of cementitious composites. CNCs were added to mortar mixtures as additives at cement volume ratios of 0.2vol%, 0.4vol%, 1.0vol%, and 1.5vol%. After 28 d of standard curing, the samples were immersed in a sulfuric acid with a pH value of 2 for 75 d. The unconfined compressive strength (UCS) test, the density, water absorption, void volume test, and thermogravimetric analysis were carried out to investigate the properties of CNC mixtures before sulfuric acid immersion. It was found that the addition of CNC reduced the volume of permeable voids and increased the hydration degree and mechanical strength of the samples. Changes in mass and length were monitored during immersion to evaluate the acid resistance of mixtures. The mixture with 0.4vol% CNC showed a reduced mass change and length change indicating its improved acid resistance.     

氧化铁/氧化锌超疏水复合材料的制备及其光催化性能

A facile approach was developed to construct Fe₂O₃-modified ZnO micro/nanostructures with excellent superhydrophobicity and photocatalytic activities. The effects of stearic acid (SA) and Fe₂O₃ on the morphological characteristics, water contact angle (WCA), and photocatalytic degradation were investigated. Superhydrophobicity results showed that WCA increased from 144° ± 2° to 154° ± 2° when the weight of SA increased from 5 to 20 mg because of the formation of a hierarchical or rough structure. Furthermore, Fe₂O₃-modified ZnO micro/nanostructure surfaces before and after SA treatment (20 mg) were chosen to evaluate the photodegradation of methylene blue (MB) dye under the support of visible light. MB degraded after 80 min of irradiation, and its photodegradation efficiencies were 91.5% at the superhydrophobic state and 92% at the hydrophilic state. This improvement in photocatalytic activity at both states might be attributed to an increase in surface area and improvement in charge carrier separation.     

夫西地酸联合抗生素抑制脓肿分枝杆菌的研究

为了探究针对脓肿分枝杆菌的抑菌方案,本研究采用MABA法测定夫西地酸等药物对脓肿分枝杆菌标准菌株及临床分离株的最小抑菌浓度MICs,棋盘稀释法测定联合抑菌作用,以及平板涂布法测定最小杀菌浓度MBCs.结果表明,单用夫西地酸、阿奇霉素、头孢曲松钠、贝达喹啉对脓肿分枝杆菌标准株的MIC90与MBC分别为50、6.25、3.13、3.13 μg/mL与 50、12.5、3.13、6.25 μg/mL, 夫西地酸联用阿奇霉素的协同指数FICI从0.09~2.0不等;夫西地酸对脓肿分枝杆菌具有良好的体外抑菌活性,且夫西地酸与阿奇霉素联用后对标准株与临床株表现出明显的协同效应,相比单药作用极大地降低药物的MIC及MBC;其与头孢曲松钠联用后对标准株与临床株分别表现出协同、相加作用;与贝达喹啉联用后对标准株与临床株分别表现出相加、无关作用.     

基于SnO2/TiO2/Au NPs纳米复合材料发展光电化学方法特异性检测唾液酸

制备了氧化铟锡（ITO）/二氧化锡（SnO₂）/二氧化钛（TiO₂）/金纳米粒子（Au NPs）纳米复合电极（ITO/SnO₂/TiO₂/Au NPs）,并利用它发展了可以选择性检测唾液酸（SA）的光电化学（PEC）法.采用旋涂法制备了ITO/SnO₂电极,并通过静电纺丝和磁控溅射技术在ITO/SnO₂表面原位合成了TiO₂纳米纤维和Au NPs.与单纯SnO₂比,ITO/SnO₂/TiO₂/Au NPs纳米复合电极的光电性能显著提高.这可能与Au NPs的局域表面等离子体共振效应（LSPR）和TiO₂/SnO₂异质结之间的协同作用密切相关.之后,通过金硫键（Au-S）将四巯基苯硼酸（4-MPBA）修饰在ITO/SnO₂/TiO₂/Au NPs电极表面,利用4-MPBA和SA之间的非特异性酯化反应,发展了可以特异性检测SA的PEC传感平台.     

IBA对月季切花‘黑魔术’保鲜效应的影响

为探究外源吲哚丁酸(IBA)对月季鲜切花的保鲜效应,采用蔗糖+水杨酸(SA)为基础保鲜液,分别添加不同浓度梯度的IBA,对月季‘黑魔术’鲜切花进行瓶插保鲜处理,观察分析鲜切花的各项生理指标.结果表明:保鲜处理12 d后,不同浓度IBA对鲜切花的生长和品质产生了不同的影响.IBA质量浓度为250 mg·L~(-1)的保鲜液处理组,鲜切花完全萎蔫,丧失观赏价值.IBA质量浓度为500 mg·L~(-1)的保鲜液处理组中,鲜切花能维持较好的花瓣形态,花朵于第6 d进入盛花期,绽放冠幅达8 cm,且最终花瓣萎蔫率仅为24.3%.同时,该处理组较其他组生理状态更佳,水分平衡值和鲜重维持在较好的水平,超氧化物歧化酶(SOD)和过氧化物酶(POD)的活性提高,花瓣中蔗糖含量显著高于其他处理组.进一步分析影响花瓣脱落相关基因的表达,其中RcSUC2,RcARF7因外源施加了蔗糖和生长素,导致体内基因表达相对于对照组显著降低,而乙烯与生长素的拮抗作用也使得RcETR1的表达显著降低.基于上述研究结果,筛选获得对月季‘黑魔术’鲜切花保鲜效果最佳的保鲜液配方.研究结果为月季切花保鲜应用提供了理论依据和技术参考.     

酸浆豆腐中产酸菌的耐高温紫外诱变

乳酸菌在食品及食品发酵行业具有广泛的应用,其中以乳酸菌发酵酸浆作为凝固剂的酸浆豆腐已逐渐成为人们关注的热点。酸浆豆腐发酵过程中以乳酸菌为优势菌,在酸浆豆腐点浆时,需在75℃以上高温下进行。普通乳酸菌无法耐受此温度且大量失活,影响产品的后熟。为了开发耐高温乳酸菌,以课题组从云南建水豆腐酸浆中分离的菌株为出发菌,通过紫外诱变的方式,温度梯度筛选获得4株耐高温产酸性能好的菌株。诱变获得4株菌均可在75℃耐高温30 min并保持较好的活性和产酸效果。研究所得突变菌株相比原始菌株均具有更好的耐热性和产酸性。其中HCUL 1.1801-1912Z活性最强、产酸能力最好,为4株菌中最优菌株,将该菌株用于发酵生产酸浆豆腐,将显著提高乳酸菌在豆腐中的活性和豆腐的品质。     

外源氨基酸对侧孢短芽孢杆菌S62-9产Brevilaterin的影响

为探究添加外源氨基酸对侧孢短芽孢杆菌S62-9(Brevibacillus laterosporus S62-9, BL)分泌抗菌肽Brevilaterin的影响,以BL发酵液的抗菌活性和Brevilaterin的组分变化为指标,分别采用琼脂扩散法和高效液相色谱法进行了分析。结果表明:添加L-缬氨酸、L-甲硫氨酸和2-氧代-3-甲基丁酸均能提高发酵液抗菌活性,抑菌直径最高可增加18.08%。添加外源氨基酸还能改变Brevilaterin的组分构成。添加L-甲硫氨酸后发酵液中只有抗菌肽组分Brevilaterin B和C,且二者间的相对比例发生反转;而添加L-缬氨酸或2-氧代-3-甲基丁酸还能促进BL分泌多种新组分。添加外源氨基酸能有效提高发酵液抗菌活性并改变抗菌肽的组分构成,研究结果旨在为人工调控微生物合成新型、高效的抗菌肽奠定一定的理论基础。     

燕麦分离蛋白消化特性和消化产物对STC-1细胞分泌胆囊收缩素的影响

为研究燕麦分离蛋白的消化特性及其消化产物对肠内分泌细胞分泌胆囊收缩素(CCK)的影响,以燕麦为原料,采用碱提酸沉法得到燕麦分离蛋白,分析燕麦分离蛋白在模拟胃肠道消化过程中的分子质量变化、氮释放规律、消化产物的氨基酸组成,计算氨基酸评分、化学评分和必需氨基酸指数,并以STC-1细胞为肠内分泌细胞模型评价消化产物对STC-1细胞分泌CCK的影响。实验结果表明:燕麦分离蛋白经胃肠消化后,消化产物的分子质量小于10kDa,释放的可溶性氮的比例为90.11%,消化产物可溶性部分中游离氨基酸的比例为22.8%,肽的比例为67.31%,并且肽的分子质量主要在1000Da以下(约74%);燕麦分离蛋白消化产物中必需氨基酸总量占38.75%,必需氨基酸与非必需氨基酸的比值为0.63,且必需氨基酸指数(0.95)大于0.90。燕麦分离蛋白消化产物对STC-1细胞影响的实验结果表明,燕麦分离蛋白消化产物对STC-1细胞生长具有显著的促进作用,且能够增加CCK的合成和分泌。研究结果表明,燕麦分离蛋白作为一种优质的蛋白质原料,不仅具有优良的营养功能,而且具有促进肠内分泌细胞分泌CCK的生物活性,在食品领域具有较大的应用潜力。