硒纳米微粒的共振散射光谱特性及其应用

在盐酸介质中,维生素C还原Se（Ⅵ）生成较稳定的硒纳米微粒.它在可见光范围内无明显特征吸收峰,在340,470,470和520 nm处产生4个共振散射峰.维生素C浓度在0.05～4.0 mg/L范围内与I340nm呈良好的线性关系.据此本文建立了一个检出限为0.01 mg/L维生素C的共振散射光谱新方法,并用于合成样品和药品中Vc含量的分析,结果满意.     

用高灵敏度分光光度法测定海豚肝脏中的微量硒

硒是生物代谢过程中必需的一种微量元素[1] .近来 ,人们研究了硒对人体及动物的作用[2 ] ,发现微量硒对许多重金属元素如隔、汞具有拮抗作用 .这种作用对于海洋哺乳类动物更为显著[3～ 5 ] .经研究还表明 ,海豚肝脏中的汞含量甚高 ,远远超过人的致死量 ,但海豚并无中毒现象 ,具有几乎与人类相同的数十年的长寿命 ,其原因可能在于海豚肝脏中的汞与硒及蛋白质形成了一种低毒性的化合物 ,从而降低了汞的毒性[4,5 ] .因此 ,准确测定海豚肝脏中硒的含量对于研究其肝脏中汞、硒化合物的化学形态和结构具有十分重要的意义 .对生物样品中硒的测定方…     

叶面施硒对大蒜生理特性、含硒量和产量的影响

采用不同浓度的亚硒酸钠进行大蒜叶面喷施的田间试验。结果表明：硒浓度500mg/kg时,其超氧化物歧化酶活性最强,且一定的硒浓度可提高大蒜过氧化氢酶的活性;施硒大蒜中全硒、有机硒和无机硒含量提高,且有机硒的转化率与硒浓度增加成正比;全硒、有机硒和无机硒含量在硒浓度10000mg／k时迭最高;≤10mg/kg的低浓度硒有利于大蒜产量的增加;综合各因素,大蒜叶面积施硒以不超过10mg/kg为宜。     

微量元素硒与大熊猫的繁殖

大熊猫卵巢囊肿,生长滤泡闭锁黄体化及雄性大熊猫性欲低下,严重影响了大熊猫的繁殖.其原因很复杂,可能与微量元素硒(Se)的缺乏有关.     

《血色沉香》：从独特视角诠释镇江地域文化

电视连续剧《血色沉香》演绎了从民国十七年到＂九.一八＂期间,以镇江楚氏家族为代表的民族资本家与日本人以及日本买办之间进行的英勇顽强的斗争,反映了旧中国民族资本家充满血泪和悲壮的家族命运。剧中经久弥香的醋文化、救死扶伤的救生会、南北气质兼具的镇江人、山清水秀的城市山林风光给观众留下了深刻的印象。     

石墨炉原子吸收光谱测定食品中的痕量硒

研究了石墨炉原子吸收光谱测定食品中痕量硒的试验方法,对原子化温度梯度、时间、灯电流及干扰因素等分析条件进行了优化选择,测定了几种食品中硒的含量和相关技术指标,结果表明:本法能快速测定食品中的痕量硒,而且测定结果令人满意[相对标准偏差<10%,标准回收率为(100±10)%].     

Effect of high pressure sintering and annealing on microstructure and thermoelectric properties of nanocrystalline Bi2Te2.7Se0.3 doped with Gd

Bi2Te2.7Se0.3of high performance doped with Gd bulk materials was prepared by a high pressure(6.0 GPa) sintering(HPS) method at 593 K,633 K, 673 K and 693 K. The sample was then annealed for 36 h in a vacuum at 633 K. The phase composition, crystal structure and morphology of the sample were analyzed by X-ray diffraction and scanning electron microscopy. The electric conductivity, Seebeck coefficient, and thermal conductivity aspects of the sample were measured from 298 K to 473 K. The results show that high pressure sintering and the doping with Gd has a great effect on the crystal structure and the thermoelectric properties of the samples. The samples are consisted of nanoparticles before and after annealing, and these nanostructures have good stability at high temperature. HPS together with annealing can improve the TE properties of the sample by decreasing the thermal conductivity of the sample with nanostructures. The maximum ZT value of 0.74 was obtained at 423 K for the sample, which was sintered at 673 K and then annealed at 633 K for 36 h. Compared with the zone melting sample, it was increased by 85% at423 K. Hence the temperature of the maximum of figure of merit was increased. The results can be applied to the field of thermoelectric power generation materials.     

Se(Ⅳ)-I--L(L=RhB,MG,MV,CV)三元配合物的合成与表征

在室温水溶液体系中分别合成了Se(Ⅳ)-I^--罗丹明B、Se(Ⅳ)-I^--孔雀绿、Se(Ⅳ)-I^--甲基紫、Se(Ⅳ)-I^--结晶紫4种三元配合物，并用等离子体原子发射光谱(ICP)、元素分析(EA)、红外光谱(IR)、紫外可见光谱(UV—Vis)、X射线衍射(XRD)等对其进行表征，确定了4种配合物的分子式为：(RhB)2(SeI6)、(MG)2(SeI6)、(CV)4(SeI8)、(CV)4(SeI8)，初步探讨了配合物的作用机理。     

Bioinformatic prediction of selenoprotein genes in the dolphin genome

Selenium (Se), an essential trace element in vivo, is present mainly as selenocystein (Sec) in various selenoproteins. The Sec residue is translated from an in-frame TGA codon, which traditionally functions as a stop codon. Prediction of selenoprotein genes is difficult due to the lack of an effective method for distinguishing the dual function of the TGA codon in the open reading frame of a selenoprotein gene. In this article a eukaryotic bioinformatic prediction system that we have developed was used to predict selenoprotein genes from the genome of the common bottlenose dolphin, Tursiops truncatus. Sixteen selenoprotein genes were predicted, including selenoprotein P and glutathione peroxidase. In particular, a type II iodothyronine deiodinase was found to have two Sec residues, while the type I iodothyronine deiodinase gene has two alternative splice forms. These results provide important information for the investigation of the relationship between a variety of selenoproteins and the evolution of the marine-living dolphin.     

微量元素硒及其硒肥

本文从硒与植物的相关姓,综述了硒对植物的生长效应,简介我国近几年来通过施硒肥以提高农作物有机硒含量的成果和我国富硒烟及其烟肥的研究进展。