二硫化钼纳米材料的制备及其对心肌细胞的保护作用

目前,心血管疾病是世界上导致死亡的主要病因,而氧化应激损伤是心血管疾病的重要发病机制之一。 本研究旨在探讨二硫化钼(MoS₂)纳米材料在心肌细胞受到氧化应激损伤时的抗氧化保护作用。 我们通过一步水热法合成了具备类抗氧化酶活性的MoS₂纳米材料。 通过MTT比色法、细胞内凋亡、细胞内活性氧(ROS)检测及Western Blot等实验证实MoS₂纳米材料(100 μg/mL)可以很好地保护H9c2心肌细胞免受双氧水(H₂O₂)诱导的氧化应激损伤。 同时,还促进了H9c2心肌细胞的增殖。 本研究显示了MoS₂纳米材料可用于构建针对氧化应激损伤引起的心血管疾病的抗氧化剂防御,为纳米药物在抗心肌氧化损伤研发提供实验数据及理论依据。     

母岩高铀离子型稀土矿采区的放射性污染风险浅析

铀与稀土元素同属大离子亲石元素,尤其与钇组稀土关系更密切,因此南岭高铀花岗岩往往同时是铀和离子型重稀土矿床的成矿母岩。国内外研究资料表明,高铀花岗岩中的铀主要以原生铀的形式存在于晶质铀矿中,在强烈风化过程中大部分发生活化转移,而采矿活动对此有显著促进作用;国外众多含铀湿地的发现及其研究资料表明,山区湿地是铀的"高效过滤器"和"沉淀池",花岗岩风化转移到水体中的微量铀经长期累积,可在湿地富有机质土壤和沉积物中富集至(3000~4000)×10^-6,而采矿和农垦活动可将湿地经几千年累积富集起来的铀释放到居民的生活环境中,因而被视为是一种环境风险。因此建议加强母岩高铀离子型稀土矿区的湿地放射性调查和环境保护,以保障湿地对重金属的天然过滤功能,避免湿地束缚铀的释放,这对保护矿区水质和生态环境都具有重要意义。     

Effects of curing agents and modified graphene oxide on the properties of XNBR composites

This paper investigates the effects of crosslinking methods on the incorporation of graphene oxide (GO) in carboxylated nitrile butadiene rubber (XNBR) in the process of producing nanocomposites for chemical-resistant protective clothing and gloves. The novel aspect of the study is a comprehensive approach involving both unmodified GO as well as GO that was carboxylated to increase its affinity to XNBR and to facilitate its application. The nanostructure of XNBR composites was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Fourier transform infrared spectroscopy (FTIR) was used to elucidate the chemical structure of the composites. Thermal stability studies were performed using differential scanning calorimetry (DSC). The barrier properties of the composites were determined based on swelling, crosslinking density, and permeation by mineral oils. The mechanical tests included resistance to puncture and abrasion, stress at strain, and tensile strength. Contact angle was measured to determine the degree of hydrophobicity of the obtained composites.AFM and SEM images revealed the effects of different curing agents (sulfur, magnesium oxide, or a hybrid system) as well as GO type on the surface morphology of XNBR composites. The type of curing agent was found to affect the kind of crosslinks formed and their spatial network structure, as confirmed by FTIR. The DSC curves showed that the crosslinking methods of XNBR did not affect glass transition temperature, but led to large changes observed in the temperature range of 130–220 °C.The type of crosslinking method affected the degree of swelling. It was found that the incorporation of carbon nanofillers led to an improvement in the abrasion and puncture resistance as well as tensile strength of XNBR composites. The water contact angle of the composites indicated hydrophobicity. The properties of XNBR composites containing GO revealed their substantial application potential in protective clothing.     

基于RF_AdaBoost模型的血液种属鉴别算法

针对人类和非人类血液种属鉴别对无损、 高效分析方法的需求, 结合随机森林(Random Forest)和AdaBoost(Adaptive Boosting Algorithm)算法, 提出了一种血液种属鉴别方法(RF_AdaBoost). 该方法将RF作为AdaBoost的弱分类器, 以达到提高模型鉴别准确度, 增强模型鲁棒性的目的. 采用RF、 支持向量机(SVM)、 极限学习机(ELM)、 核极限学习机(KELM)、 堆栈自编码网络(SAE)、 反向传播网络(BP)、 主成分分析-线性判别法(PCA-LDA)及偏最小二乘判别分析(PLS-DA)与RF_AdaBoost模型进行对比, 以不同规模血液拉曼光谱数据训练集进行鉴别实验评估其性能. 结果表明, 随着训练样本的增加, RF_AdaBoost鉴别准确度最高达100%, 预测标准偏差趋于0. 与其它模型相比, RF_AdaBoost具有较高的分类准确度及较强的稳定性, 为血液种属的鉴别工作提供了新方法.     

N-取代肌肽酰胺类衍生物的合成及生物活性

以肌肽为原料,对伯氨基进行了结构修饰,合成了11种肌肽衍生物.化合物的结构经核磁共振、紫外-可见光谱及高分辨质谱分析确证.丙烯醛清除活性测试结果表明,在实验浓度下大部分化合物表现出一定的清除丙烯醛活性,尤其是化合物4k对丙烯醛的清除活性高于肌肽.脾细胞增殖活性测试结果表明,在实验浓度下大部分化合物表现出一定的脾细胞增殖活性,特别是化合物4b,4d和4k对脾细胞的增殖活性高于阳性对照伴刀豆球蛋白A.过氧化氢诱导血管内皮细胞损伤的预保护实验结果表明,在实验浓度下大部分化合物表现出一定的预保护作用,其中化合物4a,4j和4k对过氧化氢诱导血管内皮细胞损伤的预保护作用大于肌肽.血浆稳定性实验结果表明,与肌肽相比,11种化合物均具有很好的血浆稳定性.     

Synthesis of Novel Cryptates Based on Triazole Motif: A Regioselective Approach

Regioselective syntheses of cryptands were achieved via two different approaches, first by protection–deprotection and second by cyclization reactions between 1,ω-dihaloalkanes and the lariat amino triazolophanes. The syntheses of all triazolophanes and cryptands were carried out regioselectively, and the compounds were obtained in good yields. All compounds were studied and confirmed with different spectroscopic tools.

THE SYNTHESIS OF FLUOROHETEROCYCLIC KETENE AMINALS

The synthesis of fluoroheterocyclic ketene aminals was investigated. Fluorobenzyl ketene dithioacetals 1c reacted with nitric acid in the presence of concentrated sulfuric acid to give compound 2c. 1 reacted with diamines to afford 3–4. C-fluorobenzylation of 3–4 give the corresponding 5–8.     

Direct and Convenient Method of Regioselective Benzylation of Methyl α‐D‐Glucopyranoside

A facile and convenient method for the direct preparation of methyl 2,3,6‐tri‐O‐benzyl‐α‐D‐glucopyranoside (2) by the regioselective benzylation of methyl α‐D‐glucopyranoside (1) with benzyl bromide in the presence of mild bases K₂CO₃ and KOH (1∶1) without solvents is reported.     

(NH4)3PW12O40 as an Efficient and Reusable Catalyst for the Synthesis and Deprotection of 1,1‐Diacetates

An efficient method for the synthesis of 1,1‐diacetates (acylals) from different aldehydes in the presence of (NH₄)₃PW₁₂O₄₀ and acetic anhydride under solvent‐free conditions at ambient temperature is achieved. Selective conversion of aldehydes was observed in the presence of ketones. The deprotection of acylals has also been achieved using (NH₄)₃PW₁₂O₄₀ in methanol. The catalyst was found to possess good activity and considerable level of reusability.     

Mild and Efficient Method for Oxathioacetalization of Carbonyl Compounds

An efficient procedure for the protection of carbonyl compounds into the corresponding 1,3‐oxathioacetal has been achieved using PAS as catalyst.