反相高效液相色谱和超高效液相色谱法测定 饮料中咖啡因含量的比较研究

目的对原反相高效液相色谱(RP-HPLC)方法进行转化并优化,建立超高效液相色谱(UPLC)方法,为饮料中咖啡因的含量测定提供更快速、高效、灵敏和环保的方法。方法分别采用RP-HPLC法和UPLC法测定饮料中咖啡因的含量,并对比二者的精密度、稳定性、重复性和加标回收率。结果 2种方法所得8种市售饮料中咖啡因的含量测定结果变化趋势一致,但UPLC法含量测定结果比RP-HPLC法含量测定结果偏高,二者精密度、回收率均符合要求。结论 UPLC法可以成功替代RP-HPLC法,为饮料中咖啡因的快速定性定量分析与检测提供新的途径。     

阿纳其根醇提物对D-半乳糖致衰老小鼠抗衰老作用的血清核磁共振代谢组学研究

目的 利用核磁共振代谢组学方法研究阿纳其根提取物对D-半乳糖致衰老小鼠抗衰老作用机制。方法 选取3月龄的昆明小鼠60只并将其随机分为正常组、模型组、阳性对照组和阿纳其根95%醇提物低、中、高剂量给药组,正常组以外的小鼠每天1次皮下注射D-半乳糖100mg/kg的同时对阿纳其根低、中、高剂量给药组分别灌胃相应浓度的阿纳其根95%醇提物(1.5g/kg,3.0g/kg,6g/kg),对阳性对照组灌胃盐酸多奈哌齐(0.92mg/kg),模型组灌胃等体积的生理盐水,连续给药45d, 第45d末次给药1h后利用Morris水迷宫实验观察小鼠学习和记忆能力并收集各组小鼠血清,用核磁共振波谱(_¹H-NMR)技术测定核磁共振氢谱,采用PLS-DA法和OPLS-DA法分析研究每组小鼠血清中代谢产物差异。结果 行为学检测结果显示与模型组小鼠比较,阳性对照组和阿纳其根醇提物不同剂量组的逃避潜伏期和游泳距离逐渐缩短,差异有统计学意义(P＜0.01),各组小鼠的空间探索实验,与模型组相比,阿纳其根95%醇提物各剂量组小鼠经过有效区次数增加(P＜0.05);各组血清多种代谢物有显著性差异,阿纳其根提取物低、中、高剂量给药组小鼠血清中β-葡萄糖、α-葡萄糖、脂类(VLDL)、脂类(LDL)、缬氨酸、丙酮酸、亮氨酸、酪氨酸、乳酸、组氨酸、乳酸、胆碱、甲酸含量升高;糖蛋白、谷氨酰胺、肌醇、乙酸、蛋氨酸、乙酰半胱氨酸、谷氨酰胺、肌醇、甘氨酸、肌酸、鲨肌醇、乙酸、蛋氨酸、异亮氨酸含量降低。结论 D-半乳糖诱导的衰老模型小鼠的糖代谢代谢、氨基酸代谢发生紊乱,而阿纳其根醇提物对其紊乱有一定的改善作用从而发挥抗衰老作用。     

布鲁氏菌S-2与S-19株提取的脂多糖在人布鲁氏菌病诊断抗原中的应用

目的使用脂多糖(lipopolysaccharide,LPS)提取试剂盒提取布鲁氏菌S-19与S-2菌株中的脂多糖,检测这2种脂多糖的抗原性与诊断价值。方法用工业化生产的布鲁氏菌S-19与S-2菌株菌液用LPS纯化试剂盒通过裂解、纯化、洗涤的方法提取LPS,用提取的LPS进行斑点酶联免疫吸附实验(enzyme-linked immunosorbent assay,ELISA)与布鲁氏菌病阳性、正常阴性、疱疹病、血吸虫病患者血清反应,观察反应结果并判断诊断价值。结果斑点ELISA实验结果显示从S-19与S-2株中提取的LPS与布鲁氏菌病阳性血清能作出反应,反应颜色明显,诊断价值高。结论S-19与S-2菌株中提取的LPS能与布鲁氏菌病阳性血清反应,有较好的诊断价值。     

Enhancing effect of MgO modification of Cu–Al spinel oxide catalyst for methanol steam reforming

Cu–Al spinel oxide (CA) as a sustained release catalyst has been successfully used in methanol steam reforming and it is highly required to improve its catalytic performance. Here, surface modification of the CA with various MgO loadings was performed. Characterization results showed that MgO dopant had strong interaction with the CA, resulting in a substantial change of the surface microstructure. Importantly, a small portion of lattice Cu²⁺ was phased out while partial Mg²⁺ cations incorporated into the spinel structure, giving rise to a variation of the cation distribution. Consequently, the change of the Cu²⁺ surrounding environment made it become hard to be reducible, thus the doped catalysts showed a lower copper releasing rate and smaller copper particles. Then, the activity and stability were enhanced when a suitable amount of MgO was highly dispersed. Excess amount of crystalline MgO gave rise to easy coking that resulted in an inferior catalytic performance.     

Deposition,defect and weak bond formation processes in a-Si:H

The growth of a-Si:H and the resulting weak bond and defect formation mechanism are analyzed in terms of the adsorbed SiH₃ model of growth. It is found that this model describes the surface processes well, but it needs further development to correctly describe the temperature dependence of the formation of defects and weak bonds, since the surface defect density decreases monotonically with temperature and does not show a minimum near 250°C. We show that the experimentally observed increase in hydrogen content, weak bond and defect density at lower deposition temperatures can be accounted for by a hydrogen evolution reaction from H₂^* sites.     

高效液相-示差折光法比较新疆地产8种蜂蜜中单糖的含量

目的 本文依据国标检测方法(GB/T18932.22-2003)并依据文献对其改进研究比较新疆地区8种蜂蜜中果糖、葡萄糖、蔗糖的含量,评价其真伪和质量。方法 采用 Waters carbohydrate high performance(4.6 mm×250 mm,4 μm),乙腈：水(75:25,V:V)为流动相,流速：1.0 mL/min,柱温：35℃,检测器为示差折光检测器,进样量为10 μL。结果 混标及蜂蜜样品中的果糖、葡萄糖、蔗糖和麦芽糖在10 min内均达到基线分离,加样回收率分别为98.6%～102.6%,相对标准偏差(RSD)分别为1.5%～2.6%,并且8种蜂蜜中果糖、葡萄糖含量均大于30%,蔗糖含量低于2%。结论 8中蜂蜜中山花蜂蜜果糖含量最高,枸杞蜂蜜葡萄糖含量最高,并且国标检测方法灵敏度高,分析时间短,结果准确可靠,适用于蜂蜜中糖的快速分析和质量控制。     

Plasma surface modification of titanium by TiB precipitation for biomedical applications

In order to improve the surface properties of titanium and expand its clinical application, many methods have been applied to modify its surface. In this work, properties of titanium were modified by boride microplasma surface alloying. Plasma surface alloying gives a wide range of layer thickness, which is controlled by the amount of the placed powder and process parameters. Formation of TiB phase precipitation was confirmed by XRD analysis. Additionally, the modified microstructure was observed by optical microscopy. The Vickers microhardness was significantly improved from 180 HV for original titanium substrate to 900 HV in obtained composite layer structure, with a smooth hardness reduction in the cross section profile. Strong heat penetration from microplasma melt-in technique led to substrate dissolution with formation of stable TiB phase dispersed in α-Ti matrix. The electrochemical treatment in phosphoric acid electrolyte resulted in developed surface formation, attractive for tissue fixing and growth. In vitro cytocompatibility of these materials was evaluated and compared with a conventional microcrystalline titanium, where normal human osteoblast (NHOst) cells from Lonza (CC-2538) were cultured on the disks of the materials and cell growth was examined. The results of the in vitro test suggest that TiB phase dispersed in α-Ti matrix displays good cytocompatibility, compared to that of microcrystalline titanium. Additionally, the SEM observation reveals a significant difference in morphological characteristics of the cells on developed and polished material, just after 1 day of cell culture. It can be concluded that, plasma alloying is an effective method to produce TiB phase dispersed in α-Ti matrix with high hardness, good cytocompatibility, which makes them potential candidates for biomedical applications.     

Crystallization and functionality of inorganic materials

In this article, we briefly summarized our recent work on the studies of crystallization and functionality of inorganic materials. On the basis of the chemical bonding theory of single crystal growth, we can quantitatively simulate Cu₂O crystallization processes in solution system. We also kinetically controlled Cu₂O crystallization process in the reduction solution route. Lithium ion battery and supercapacitor performances of some oxides such as Co₃O₄ and MnO₂ were shown to elucidate the important effect of crystallization on functionality of inorganic materials. This work encourages us to create novel functionalities through the study of crystallization of inorganic materials, which warrants more chances in the field of functional materials.