电热解—塞曼原子吸收光谱法用于 总膳食样品中痕量汞的快速测定

目的 进一步推进测汞仪在低含量样品总汞含量检测中的运用。方法 同时采用原子荧光光谱法和测汞仪标准加入法定量检测部分总膳食样品。结果 运用原子荧光光谱法对低汞含量总膳食样品进行检测,样品总汞含量范围为1.33μg/kg～41.14μg/kg;运用测汞仪标准加入法对低汞含量总膳食样品进行检测,样品总汞含量范围为1.32μg/kg～32.07μg/kg。测汞仪标准加入法与原子荧光光谱法对同种总膳食样品中总汞含量检测结果接近。结论 测汞仪标准加入法不仅具有省时、快速检测的优势,而且可以保证测定结果的准确性。     

轴向送粉等离子喷涂Ni/Al2O3涂层的力学及微波介电性能

以轴向送粉等离子喷涂法制备了Ni/Al2O3陶瓷涂层,分析了Ni含量变化对涂层材料的显微结构、力学性能及微波介电性能的影响.结果表明,随着Ni含量增加,涂层中Ni粒子的分布逐渐由孤立向部分桥连方式转变;陶瓷涂层的相对密度、抗弯强度呈下降趋势,这主要是由于在陶瓷涂层中Ni与Al2O3不润湿,Ni与Al2O3热膨胀系数不匹配从而形成空隙引起的.涂层断裂韧性随Ni含量的增加而升高,则是由于材料中Ni粒子发生了延展变形和引起裂纹转向.复介电常数性能测试结果表明,在8.2～12.4GHz微波频率范围内,陶瓷涂层复介电常数的实部值随Ni粒子含量的增加先逐渐上升后逐渐下降,复介电常数的虚部上升.这与Ni粒子形成的桥连结构有关.     

Morphology-tunable synthesis of SrWO<Subscript>4</Subscript> crystals via biomimetic supported liquid membrane (SLM) system

SrWO₄ crystals with various morphologies have been synthesized via a system of supported liquid membrane in the presence of different additive reagents at room temperature. The X-ray diffraction patterns show that the obtained SrWO₄ crystals belong to tetragonal structure. Scanning electron microscopy results reveal that additive reagents can highly affect the morphology and size of SrWO₄ crystals. In fluorescence spectra there is a blue-shift emission peak at room temperature, which shows that it has potential applications in device designs and photoelectron fields. A possible growth mechanism is discussed. An erratum to this article can be found at     

Na2O-TeO2系统中的一个新晶相

在Na2O-TeO2系统中发现了一个未知的新晶相，探索了该晶相的确切成分和形成条件，并根据实验结果，对现有的相图作了相应的修改，该晶相的具体成分为Na2O8TeO2。此晶相在330℃下能稳定存在，当温度达到或高于340℃时则分解成Na2O.4TeO2和TeO2两个晶相。     

OFDMA系统中资源公平调度算法研究

研究了宽带正交频分复用多址（OFDMA）系统中存在多种不同业务时的无线资源公平调度问题,深 入分析了经典的资源调度算法———用户最小容量最大化算法,提出了一种明显改善公平性能的改进算法,仿真 结果证明,改进算法在各种应用环境下,都具有良好的公平性能,能为不同业务类型的用户提供较严格的速率 保证。     

浅谈乳酸茵

乳酸菌是动物肠道中极为重要的生理菌群之一,无毒、无副作用,担负着人畜机体多重要的生理功能。本文简要介绍了乳酸菌的科学与技术发展概况及生物学特性,阐述了乳酸菌的几种生理功能及其在禽生产中的应用。     

硼元素抗烟草马铃薯Y病毒脉坏死株系(PVYN)的应用研究

采用营养元素硼对烟草植株进行喷施处理后接种马铃薯Y病毒脉坏死株系(PVYN),对感染植株的病情指数及体内病毒含量进行了测定.结果表明:采用不同浓度硼元素5(B1)、10(B2)、20(B3)、30(B4)和40(B5)mg/L处理烟株24 h后再接种pVyN,对烟草感病后体内病毒的增殖有一定的抑制作用,能明显降低烟株体内病毒含量.其中以B3处理对pvyN抗性最好,喷施24 h后接种pVyN为硼元素的最佳诱抗时间,且从表观上看,亦可延迟脉坏死症状的发生.由此可见,硼元素对抑制pVyN效果显著,可作为一种新型药剂进行开发.     

Protection of curcumin against fructose-induced hyperuricaemia and renal endothelial dysfunction involves NO-mediated JAK–STAT signalling in rats

Increasing evidence has demonstrated that excess fructose consumption as a risk factor for metabolic syndrome causes hyperuricaemia and renal injury. Curcumin, a natural plant phenolic food additive, lowered serum urate, creatinine and blood urea nitrogen levels, and increased urinary urate and nitrate/nitrites levels, as well as renal nitric oxide (NO) production in fructose-fed rats. Moreover, curcumin regulated urate transport-related proteins and inhibited activation of the JAK2–STAT3 cascade and overexpression of SOCS3 and TGF-β1 in the kidneys of fructose-fed rats. These results suggested that the anti-hyperuricaemic and renal protective actions of curcumin might be the result of renal NO-mediated JAK2–STAT3 signalling and TGF-β1 normality, which ameliorated renal endothelial dysfunction to improve renal urate transporter system in this model. The present study may provide the evidence for the potential use of a functional food ingredient curcumin because of its action against hyperuricaemia and renal injury induced by high fructose intake.     

In vitro antioxidant activity of enzymatic hydrolysates prepared from abalone (Haliotis discus hannai Ino) viscera

Pacific abalone (Haliotis discus hannai Ino) viscera, which are normally discarded as byproducts, were hydrolyzed with five commercially available proteases, including alkali protease, papain, neutral protease, pepsin, and trypsin. The hydrolysates obtained were fractionated using ultrafiltration membrane bioreactor system. The resulting hydrolysate fractions were investigated for their antioxidant activities, including the scavenging effect on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, the scavenging effect on hydroxyl radical, and the reducing power. Results showed that the hydrolysate fractions were effective antioxidants, and the antioxidant activity of the hydrolysates was related to the enzyme type employed. As byproducts, abalone viscera can be used as a potential source of antioxidant peptides.     

Structural analysis of a polysaccharide from <Emphasis Type="Italic">Patinopecten yessoensis</Emphasis> viscera

A water-soluble polysaccharide, SVP-2, was obtained from Patinopecten yessoensis viscera. Its major structural features were elucidated using composition analysis, methylation analysis, periodate oxidation and Smith degradation, partial acid hydrolysis, and NMR spectroscopy. The results indicated that SVP-2, with an average molecular weight of 170 kDa, was composed of rhamnose, fucose, arabian, xylose, mannose, galactose, and glucose in molar ratios of 1.65:2.54:4.05:5.60:1.48:4.90:1.00. Furthermore, it could deduce that the backbone of SVP-2 consisted of 1,3,4-linked pyran fucose, 1,3,4-linked pyran galactose, and 1,3-linked pyran arabian residues.