响应面法优化制备LDHs-CRMA复合改性沥青及其表征

采用熔融共混法，以克拉玛依90^#沥青为原料，Mg-Al水滑石(LDHs)与废橡胶粉(CR)作为改性剂，制备了具有抗紫外老化性能的水滑石/废胶粉复合改性沥青(LDHs/CRMA)，并对其软化点、针入度指数(PI)、延度进行了测试。通过Hassan数学方法将三个指标“归一化”得到总评“归一值”，采用响应面分析法建立总评“归一值”与各因素之间的Box-Behnken数学模型，得到了LDHs/CRMA的最优制备工艺条件为：剪切温度173℃、剪切时间89 min、剪切速率3500 r/min。通过紫外老化模拟实验对复合改性沥青的抗老化性能进行了评价，结果表明，引入水滑石可以减少沥青老化过程中含氧官能团的产生，抗紫外老化性能得到了明显提高。     

Preparation and characterisation of films from xylose‐glycosylated peanut protein isolate powder

This work aimed at producing and characterising xylose‐glycosylated peanut protein isolate (PPI‐X) films by dissolving PPI‐X powder in water at ambient temperature and further plasticising with glycerol. The effect of powder dissolution temperature (20–100 °C) and glycerol concentration (15.0–45.0%, w/w) on mechanical properties and integrity of these films was quantified. The results showed that the powder dissolution temperature had no significant effect on the mechanical and water resistance properties of PPI‐X films within the temperature range tested. With increasing concentration of glycerol, the tensile strength and water resistance of PPI‐X films decreased and elongation increased. The films produced by dissolving the PPI‐X powder at 20 °C and plasticising with 25.0% glycerol had comparable mechanical properties and better water resistance compared to some other plant protein films plasticising with glycerol. The results suggested that PPI‐X films could potentially be used as biodegradable packaging materials.     

来瓦希尔骨架材料MIL-53(Al)填充PEBA膜渗透汽化分离水中苯胺

将来瓦希尔骨架材料MIL-53(Al)引入到聚醚共聚酰胺（PEBA-2533）高分子相中制备了不同填充量的PEBA/MIL-53(Al)杂化膜并用于渗透汽化分离水中微量苯胺。X-射线衍射结果证实MIL-53(Al)被成功合成。扫描电镜和激光粒度分析结果表明所制备MIL-53(Al)颗粒粒径在纳米尺度范围内。采用扫描电镜、红外光谱、X-射线衍射、差示扫描量热和水接触角对杂化膜进行了表征，并考察了杂化膜的溶胀行为和分离性能。结果表明，所得杂化膜的热稳定性较好。当MIL-53(Al)质量分数小于20%时，MIL-53(Al)在高分子相中分散均匀，继续增大填充量出现团聚现象。杂化膜的结晶度随MIL-53(Al)填充量的增加而降低。MIL-53(Al)的引入增强了杂化膜的疏水性和溶胀度。在料液温度为60℃、膜下游压力400Pa、料液苯胺质量分数为3.6%时，MIL-53(Al)质量分数为20%的杂化膜（M-20）综合分离性能最优，渗透通量达到2.15kg/(m²·h)，分离因子为264。12天的稳定性测试结果表明所得杂化膜分离性能无显著变化，能够满足渗透汽化应用要求。     

Safe preparation of beefy meaty peptide with Bacillus subtilis

Preparation of flavour peptides with microorganisms is an attractive choice for its large-scale production. However, beefy meaty peptide (BMP), as a research hotspot in the field of umami peptide, has been studied in few microorganisms, and furthermore, the safe preparation of BMP has not yet been reported. In this study, multi-copy BMP (8BMP) was successfully expressed and produced in the ‘generally recognized as safe’ Bacillus subtilis (B. subtilis). Firstly, 8BMP with the potentially intense umami was screened out based on molecular docking analysis. Then, it was successfully expressed in the B. subtilis 168 and verified through sensory evaluation. Finally, the scaling capacity of 8BMP was evaluated in a 5-L fermenter, with the highest yield (0.84 g L⁻¹) 6.4 times than that of shake flask, which is conductive for industrial production of BMP and other food peptides.     

现代镀覆技术 第二部分──化学镀镍(续4)

给出了各种实用的化学镀镍配方及其工艺条件。     

X射线荧光光谱在铜矿石分析中的应用文献评介

作者收集了我国用X射线荧光光谱(XRF)分析技术进行铜矿石(含铜精矿)分析的文献共计51篇,其中野外现场分析文献21篇,实验室内分析文献30篇。实验室内方法文献包括熔融制样法12篇,粉末压片制样的15篇,其他方法3篇。文章用列表方式对文献要点进行了介绍,对其中的多元素分析方法文献进行了重点评介,也特别讨论了X射线荧光光谱分析的技术条件、制样方法选取、标准物质与标准方法等问题。文献表明:XRF已成为铜矿石主次痕量分析最强有力的技术方法之一,并随着社会对环境需求的增长,直接粉末压片制样的XRF方法必将具有更广阔的发展前景。全篇引文89篇。     

Structural-microstructural characterization and optical properties of Eu3+,Tb3+-codoped LaPO4·nH2O and LaPO4 nanorods hydrothermally synthesized with microwaves

Rhabdophane-type Eu³⁺,Tb³⁺-codoped LaPO₄·nH₂O single-crystal nanorods with the compositions La_0.99999-xEu_xTb_0.00001PO₄·nH₂O (x?=?0–0.03), La_0.99999-yTb_yEu_0.00001PO₄·n′H₂O (y?=?0–0.010), and La_0.99999-zTb_zEu_0.000007PO₄·n′′H₂O (z?=?0–0.012) were hydrothermally synthesized with microwaves. It is shown that the Eu³⁺,Tb³⁺ codoping does not affect the thermal stability of these nanorods, which is due to the formation of substitutional solid solutions with both Eu³⁺ and Tb³⁺ replacing La³⁺ in the crystal lattice. Moreover, it is also shown that monazite-type Eu³⁺,Tb³⁺-codoped LaPO₄ single-crystal nanorods can be obtained by calcining their rhabdophane-type Eu³⁺,Tb³⁺-codoped LaPO₄·(n,n′ or n′′)H₂O counterparts at moderate temperature in air, and that they are thermally stable. It is also observed that, for the same Eu³⁺,Tb³⁺-codoping content, the monazite-type Eu³⁺,Tb³⁺-codoped LaPO₄ nanorods exhibit higher photoluminescent efficiency than the rhabdophane-type Eu³⁺,Tb³⁺-codoped LaPO₄· (n,n′ or n′′)H₂O nanorods. Moreover, it is found that the highest photoluminescence emission corresponds to the monazite-type La_0.96999Eu_0.02Tb_0.00001PO₄ nanorods for the La_0.99999-xEu_xTb_0.00001PO₄ system. However, for those compositions energy transfer from Tb³⁺ to Eu³⁺ does not occur. In addition, for an efficient energy transfer to occur, a content of at least 1?mol% Tb³⁺ is needed in all the studied materials.     

海参二肽基肽酶Ⅳ抑制肽的酶解制备及结构鉴定

通过抑制二肽基肽酶IV(Dipeptidyl-peptidase IV, DPP-IV)的活性,从而减少GLP-1的降解,提高血液中胰岛素的水平,是控制血糖水平的一种重要手段。本文以海参(Holothariatubulosa)为原料,通过探究蛋白酶种类、加酶量和酶解时间对酶解产物DPP-IV抑制活性、蛋白回收率和水解度的影响,确定了海参DPP-IV抑制肽的制备条件,并进一步测定了其分子量分布和总氨基酸组成,最后通过UPLC-MS/MS鉴定了其潜在的活性肽序列。结果发现,木瓜蛋白酶与复合蛋白酶1:1的复配酶解具有最佳的酶解效果,其产物的得率和DPP-IV抑制活性均最高,且在加酶量为干海参质量的1%,酶解时间为4 h时,海参酶解产物在终浓度为2 mg/mL时的DPP-IV抑制率为66.97%,蛋白回收率为76.25%,水解度为6.10%。酶解产物的分子量大都小于5000 u,且富含脯氨酸(Pro)和丙氨酸(Ala)等与抑制DPP-IV活性有关的氨基酸。将获得的酶解物中的肽段进行液质联用检测,并通过Mascot分析筛选得到28条具DPP-IV抑制肽的肽序列,分子量在500～1936 u。本实验结果为以海参为原料进行降血糖产品的开发奠定了基础。     

大豆蛋白乳液的研究进展

食品乳液作为活性物质的传递体系一直是国内外的研究热点。大豆蛋白作为一种植物高分子蛋白质,具有独特的营养价值和良好的乳化性,在改善食品感官品质和提高乳液体系稳定性上具有显著的优势。由于双亲性和高表面活性,大豆蛋白乳液得到了迅速的发展,纳米乳液、微米乳液、多重乳液、Pickering乳液、多层乳液等新型乳液以及基于乳液的固体脂质颗粒、微胶囊化和水凝胶填充颗粒,在食品、保健品、化妆品等领域有着广泛的应用前景。本研究主要综述了大豆蛋白基本结构与功能特性的关系,阐明了大豆蛋白乳液的基本性质与制备方法,并对大豆蛋白乳液的应用以及未来的发展前景进行了展望,以期为大豆蛋白乳液的加工与应用提供参考。