Chromatographic speciation of anionic and neutral selenium compounds in Se-accumulating Brassica juncea (Indian mustard) and in selenized yeast

Selenium-accumulating plants such as Brassica juncea (Indian mustard) concentrate the element in plant shoots and roots. Such behavior may provide a cost-effective technology to clean up contaminated soils and waters that pose major environmental and human health problems (phytoremediation). Such ability to transform selenium into bioactive compounds has important implications for human nutrition and health. Element selective characterization of B. juncea grown in the presence of inorganic selenium under hydroponic conditions provides valuable information to better understand selenium metabolism in plants. The present work determines both previously observed organoselenium species such as selenomethionine and Se-methylselenocysteine and for the first time detects the newly characterized S-(methylseleno)cysteine in plant shoots and roots when grown in the presence of selenate or selenite as the only selenium source. A key feature of this study is the complementary role of selenium and sulfur specific chromatographic detection by HPLC with interfaced inductively coupled plasma mass spectrometry (ICP-MS) detection and by derivatization GC with interfaced atomic spectral emission. HPLC-ICP-MS limits of detection for such species were in the range 5-50 ng Se mL(-1) in the injected extracts. Speciation profiles are compared with those of selenium-enriched yeast by both HPLC-ICP-MS and GC-AED.     

Stark shift of the A2Pi(1/2) state in 174YbF

We have measured the Stark shift of the A2Pi(1/2)-X2Sigma+ transition in YbF. We use a molecular beam triple resonance method, with two laser transitions acting as pump and probe, assisted by an rf transition that tags a single hyperfine transition of the X state. After subtracting the known ground state Stark shift, we obtain a value of 70.3(1.5) Hz/(V/cm)2 for the static electric polarizability of the state A2Pi(1/2) (J=1/2),f by fitting our data to a purely quadratic Stark shift in the interval 0-5 kV/cm. A more exact analysis that does not assume a perfectly quadratic Stark effect yields the value mu(e)=2.48(3) D for the electric dipole moment of the A2Pi(1/2)(v=0) state.     

承载浪漫回忆的水都情怀安德烈·瑞欧《情定威尼斯》

来自荷兰马斯垂特,有“当代华尔兹之王”之称的安德烈·瑞欧在1987年创办约翰·施特劳斯管弦乐团之后,渐渐地在欧洲乃至全球广受喜爱。从一开始演奏史特劳斯家族与维也纳圆舞曲,到后来的各种改编曲目,多样化的曲目,以各种多元形式将管弦乐的优美结合流行、电影、舞台剧与民谣等音乐形态,从不同的尝试中提升普罗大众欣赏音乐的品味。而且演出中永远不会缺少娱乐性,将古典乐深入浅出地演绎已经让安德烈·瑞欧与约翰·施特劳斯管弦乐团成为当今轻古典音乐界的风向标。     

为她点个赞琳赛·斯特林最新专辑《震撼出击》

全新大碟《震撼出击》(Shatter Me)的推出,再次令到琳赛·斯特林(Lindsey Stirling)走到了大家的注视之下.琳赛·斯特林这位当下美国炙手可热的小提琴美少女,不但拥有高超的演奏技巧,还集舞蹈家、作曲家于一身.早在2000年,令人目眩的视频一经YouTube“Lindseystomp”频道播出,便引发狂热转发追捧,令很多人记住了这个精灵般的女孩.她之所以能脱颖而出,不单单在于她的小提琴拉得比别人更加熟练:Lindsey还自创小提琴的歌曲,并在歌曲里加进了Dubstep的元素,让她的歌曲显得更加与众不同.对于喜爱琳赛·斯特林的乐迷来说光是收听她的音乐已然不够,当然还需配上视觉体验,在YouTube欣赏她的唯美MV,感受美景华服与跳跃灵动.     

肆意挥洒的音韵《高参小提琴实况录音辑》

作为一家专注于古典音乐制作的唱片公司,达人艺典在国内的确给人独树一帜的感觉,凭借优异的录音水平和高品位的作品选择,不但网罗了一大批优秀的艺术家,与国内众多知名乐团保持着良好的合作关系,更在广大爱乐者中建立了良好的口碑。达人艺典为音乐家提供一个平台,全程为音乐家服务,从录制到出版再到推广,尤其是针对中国乐团与青年音乐家提供平台、提供资源,让他们的优秀作品打动爱乐者,让唱片发烧友对中国自身音乐产业刮目相看。近两年,达人艺典推出了多张叫好又叫座的唱片,例如填补了中国室内乐作品空白的《上交14琴-大提琴》、《上交弦乐四重奏》、《中国爱乐艺术家四重奏》。又如单独为小提琴家李沛出版的《李沛小提琴专辑》,而今次要说到的则是达人艺典为国内另一位小提琴演奏家高参所出版的最新唱片《高参小提琴实况录音辑》。录音中小提琴演奏家高参将自己的音乐天赋及对音乐的热爱,与世界名琴融合在一起倾情演绎,令人沉醉。     

Oscillatory persistent currents in self-assembled quantum rings

We report the direct measurement of the persistent current carried by a single electron by means of magnetization experiments on self-assembled InAs/GaAs quantum rings. We measured the first Aharonov-Bohm oscillation at a field of 14 T, in perfect agreement with our model based on the structural properties determined by cross-sectional scanning tunneling microscopy measurements. The observed oscillation magnitude of the magnetic moment per electron is remarkably large for the topology of our nanostructures, which are singly connected and exhibit a pronounced shape asymmetry.