基于乙酰胆碱酯酶和氧化应激研究海胆酮对阿尔茨海默症的作用机制

海胆酮是一种酮式类胡萝卜素，主要从海胆及藻类等海洋生物中提取。本文研究海胆酮对乙酰胆碱酯酶（acetylcholinesterase，AChE）的抑制作用，应用酶动力学、荧光光谱、圆二色光谱和分子对接技术研究海胆酮对AChE的抑制机理，并用淀粉样β蛋白片段25～35（amyloid beta-peptide 25-35，Aβ25-35）诱导大鼠肾上腺嗜铬细胞瘤细胞（PC12细胞）建立阿尔茨海默症（Alzheimer’s disease，AD）模型，研究海胆酮对AD细胞模型氧化应激损伤的作用。结果表明，海胆酮有很强的AChE抑制活性，其半抑制质量浓度为（16.29±0.97）μg/mL，抑制常数Ki为3.82 μg/mL，表现为竞争性抑制；海胆酮可诱导AChE二级结构改变，更容易与AChE活性中心氨基酸Ser200、His440、Trp84和Tyr121结合，阻碍底物碘代硫代乙酰胆碱（acetylthiocholine iodide，ATCI）与酶结合，从而引起酶活力降低。海胆酮能有效抑制Aβ25-35诱导PC12细胞的AChE活力，降低丙二醛含量，增加超氧化物歧化酶、过氧化氢酶和谷胱甘肽过氧化物酶活力，减轻Aβ25-35诱导的PC12细胞氧化应激损伤。本研究基于AChE和氧化应激阐明了海胆酮对AD的潜在作用机制，为海胆酮在功能食品、生物医药等领域的应用提供了数据支持和理论根据。     

Effect of Y2O3 on the structural,optical and radiation shielding properties of transparent Na-rich borate glass with diluted and fixed Fe2O3

We study the impact of yttrium oxide (Y₂O₃) on the optical properties of iron-doped borate glasses. A series of borate glasses, with a diluted and constant amount of Fe₂O₃, doped with various amounts of Y₂O₃ (labeled as BNaFeY-glasses) was prepared and studied. The impact of Y₂O₃ doping on the optical transitions of BNaFeY-glasses was studied by analyzing the optical absorption spectra. The presence of Fe cations, with their Fe³⁺ state, leads to the appearance of absorption in the ultraviolet region. Furthermore, the optical transmittance spectra proved the transparency of all BNaFeY-glasses. Moreover, the transmittance of the sample with the highest Y₂O₃ content is about 93 % within the visible range. Because of the diluted Fe content within BNaFeY-glasses, the five absorption bands of Fe are not observed. So, these bands are detected by magnifying the spectra within the visible region. These bands are labeled ?₁, ?₂, ?₃, ?₄ and ?₅ at wavelengths 454.5, 518.4, 652.5, 707 and 808 nm respectively. These bands were used to calculate the crystal field splitting (10Dq) for all BNaFeY-glasses. The outstanding 10Dq increment with further Y₂O₃ doping was explained in terms of more interactions between Fe cations and their surroundings. On the other side, the shielding parameters were considered to examine the competence of these transparent glasses against nuclear radiation. We found that the sample doped with the highest amount of Y₂O₃ has the highest linear attenuation coefficient and the lowest half-value layer (HVL). From the HVL results, we need a thickness of 3.646 cm from the sample with 5 mol% of Y₂O₃ to get protection from 50% of the photons with energy of 0.662 MeV, and this thickness is increased to 5.137 cm when the energy is 1.333 MeV.     

Direct additive manufacturing of melt growth Al2O3-ZrO2 functionally graded ceramics by laser directed energy deposition

Functionally graded ceramics (FGC), which combine properties of different ceramics in one part, usually have better comprehensive function and structural efficiency. In this study, four different gradient transition Al₂O₃-ZrO₂ FGC samples were prepared by laser directed energy deposition (LDED) method. The results show that there is an obvious interface in direct transition sample. The transition section bears tensile stress caused by difference of thermophysical properties of materials, resulting in significant longitudinal cracks. Element transition in interface region shows a step sharp transition. The direct transition sample shows intergranular fracture and the bonding strength is very low. Gradient transition mode can effectively suppress cracks, and avoid the step transition of microstructure and elements. Elements, microhardness of 25, 20 wt% FGC samples realized a nearly linear smooth transition. The interface fracture of FGC samples changed to transgranular fracture, bonding strength was significantly improved, and the maximum flexural strength reached 160.19 MPa.     

解脂耶氏酵母作为微生物细胞工厂的应用研究进展

解脂耶氏酵母（Yarrowia lipolytica）是一种重要的工业微生物菌种，被公认为食品级安全微生物。近年来，随着合成生物学和基因编辑技术的快速发展，科学家们利用合成生物学及基因编辑技术已经成功构建出了能够生产生物化学品、生物燃料、香料、药物、工业酶和药用蛋白等多种高附加值工业产品的解脂耶氏酵母细胞工厂，使得该酵母在食品、药品和生化能源等领域均具有巨大的应用潜力。本文将重点介绍解脂耶氏酵母表达系统、合成生物学元件和基因编辑方法的最新研究进展和应用情况，并对近年来以解脂耶氏酵母作为微生物细胞工厂生产高附加值产品的应用实例进行总结，希望为研究人员进一步利用解脂耶氏酵母进行底盘细胞设计、构建和优化相关合成途径并最终实现目的产物的高效合成提供有用的信息。     

热烫温度对小麦面团介观特性的影响机制

本实验以热烫面团为研究对象，通过凯氏定氮法、粒径分析、傅里叶变换红外光谱以及快速黏度分析等手段，研究55、65、75、85 ℃和95 ℃热烫温度下小麦面团中麦谷蛋白大聚体的质量分数、粒径分布、蛋白质二级结构以及面团中淀粉的糊化特性的变化情况。结果表明：随着热烫温度的升高，面团中麦谷蛋白大聚体质量分数呈现显著增大的趋势（P＜0.05），小粒径的麦谷蛋白大聚体向中粒径和大粒径转变；面团中蛋白质二级结构发生变化，部分α-螺旋和β-折叠结构转变为β-转角和无规卷曲。同时，面团中淀粉的糊化度随着热烫温度的升高逐渐增大；淀粉的峰值黏度、最低黏度、衰减值、最终黏度、回生值和峰值时间均呈现出减小的趋势，在热烫温度高于75 ℃时，这种变化更加显著。     

金针菇多糖对微冻大黄鱼及其鱼片品质变化的影响

为研究金针菇多糖（polysaccharide from Flammulina velutipes，FVP）对微冻大黄鱼及鱼片在贮藏期间肌原纤维蛋白性质的变化及水分分布的影响，实验分别选用0.03、0.06、0.09 g/L FVP浸渍处理大黄鱼和鱼片，以无菌水处理为对照组，分析微冻贮藏期间样品的感官指标得分、总挥发性盐基氮含量、总巯基含量、Ca2＋-ATPase活性、蛋白流变学性质以及水分迁移变化规律。结果表明：FVP可有效抑制整鱼总挥发性盐基氮含量上升和感官得分的下降；减缓整鱼及鱼片在微冻过程中总巯基含量、Ca2＋-ATPase活性下降和水分流失；此外FVP还能够延缓大黄鱼因腐败而出现的蛋白凝胶能力减弱。在本实验选取的多糖浓度范围内，0.09 g/L FVP处理组保鲜效果较强。该研究结果可为FVP用于水产品贮运保鲜提供理论参考。     

大豆油体蛋糕的制作及品质分析

目的 为比较大豆油体、单甘脂和蔗糖酯三种成分对蛋糕烘焙学特征的影响。方法 本文通过对蛋糕面胚比容、质构，蛋糕面糊比重、黏度和表面气孔特性以及理化指标检测，并对蛋糕进行感官评定进行测试。结果 结果表明，大豆油体最适添加量为4.5%。大豆油体能增加蛋糕的黏度，有助于形成稳定的乳化体系，并且大豆油体蛋糕的酸价、过氧化值和反式脂肪酸检测结果符合国家标准。结论 大豆油体和乳化剂能显著提高豆乳奶油蛋糕的比容，降低硬度，从而改善蛋糕的品质特性。     

Clinical significance of contact lens related changes of ocular surface tissue observed on optical coherence images

PurposeTo investigate the relationship between the real contact lens imprint into the conjunctival tissue, observed by optical coherence tomography (OCT) and conjunctival staining and contact lens wearing comfort.Methods17 participants (mean age = 26.6 SD ± 3.6 years; 7 females) were fitted with three different contact lenses base curves of the same silicone hydrogel custom lens type (Visell 50; Hecht Contactlinsen, Au, Germany) in a randomised order. One lens was optimally fitted according to the manufacturer's recommendation, one fitted 0.4 mm flatter and one fitted 0.4 mm steeper. After 4 h of lens wear the contact lens edge in the area of the conjunctiva was imaged nasally and temporally using OCT (Optovue iVue SD-OCT). To correct the artefact due to optical distortion with OCT, the imprint of all worn lenses was measured on a glass plate afterwards. Conjunctival staining in the limbal region after 4 h of lens wear was classified using the CCLRU Grading Scale. Comfort scoring was based on visual analog scales from 0 (very poor) to 100 (excellent).ResultsThe mean conjunctival imprint of all contact lens edges was 32.0 ± 8.1 μm before and 7.3 ± 6.5 μm after distortion correction of the OCT images. The distortion corrected conjunctival imprint with the 0.4 mm steeper lens (11.5 ± 6.2 μm) was statistically significantly greater compared to the optimally fitted lens (6.5 ± 5.9 μm) (One-way ANOVA followed Tukey-test; p = 0.017) and greater compared to the 0.4 mm flatter lens (3.9 ± 5.3 μm) (p < 0.001). There was no statistically significant difference between the optimally fitted lens and the 0.4 mm flatter lens (p = 0.209). The nasally measured imprint (11.4 ± 9.0 μm) was significantly greater than the temporally measured (3.3 ± 7.6 μm) (p < 0.001). There was no statistically significant correlation between the amount of conjunctival imprint and the graded conjunctival staining (p = 0.346) or the wearer’s comfort (p = 0.735).ConclusionsContact lens edges imaged by OCT exhibited displacement artefacts. The observed conjunctival imprints are a combination of real conjunctival compression and artefacts. A deeper imprint of the contact lens into the conjunctiva caused by a steeper base curve was not related to clinically significant staining or changes in comfort after 4 h of lens wear. The observed differences between nasal and temporal imprint are likely to be caused by variations of conjunctival thickness and the shape of the underlying sclera.     

A comparative study on the performance of M (Rh,Ru, Ni)-promoted metallurgical waste driven catalysts for H2 production by glycerol steam reforming

A comprehensive study was conducted on the performance of M-promoted (M = 1%Ru, 1%Rh, 5%Ni) upgraded slag oxide metallurgical waste catalysts (M-UGSO) for hydrogen production by glycerol steam reforming (GSR). The results confirmed that the tendency of the incorporated metal to interact with Mg/Fe containing species within UGSO plays a key role in the surface availability of the corresponding metal, structural changes after reduction, and catalyst stability. Aside its best stability, 5% Ni-UGSO showed a performance (glycerol conversion to gaseous products of 100% and H₂ yield of 74%) comparable with 1% Rh-UGSO (100% and 78%, respectively) or even surpassing that of 1% Ru-UGSO (94% and 71%, respectively), as noble metal-based catalysts. Synergistic cooperation was achieved by incorporated metals (M) and Fe/Mg containing species within UGSO, resulting in enhanced glycerol and water activation. The weakest results of Ru-UGSO could be justified by lack of propensity for MgO–RuO₂ interaction on UGSO surface.