Sc掺杂Nd:CaF_2激光晶体的结构及其光谱性能参数

采用温度梯度法生长了0.5at%Nd、xat%Sc:CaF_2(x=0,2,5,8)系列晶体,测试了晶体的吸收光谱、荧光光谱和荧光寿命。研究发现发射强度和荧光寿命随着Sc^(3+)离子浓度的增加而提高。通过改变Sc^(3+)离子的浓度发现,当掺杂5at%Sc^(3+)时可以获得最大的吸收截面为1.42×10^(–20) cm^2。另外,掺入Sc^(3+)使共掺晶体在吸收光谱796 nm处产生新峰。综上,通过调节Sc^(3+)离子浓度,可以改变Nd^(3+)离子的局域结构,优化晶体的光谱性能。

Yb掺杂Ca(1-x)RxF(2＋x)(R=La,Gd)激光晶体的结构与光谱性能参数的研究

采用坩埚下降法生长了两个系列晶体3at%Yb:Ca_(1-x)R_xF_(2+x)(R=La,Gd;x=0,0.01,0.03,0.06,0.09),测试了晶体的XRD、拉曼光谱、吸收光谱、荧光光谱、荧光寿命。系统地研究了调剂离子La^(3+)、Gd^(3+)对Yb:CaF_2晶体晶格常数、拉曼光谱和光谱性能的影响规律,分析讨论了Yb^(3+)离子的结构与光谱性能之间的关系。研究结果表明,随着La^(3+)、Gd^(3+)掺杂浓度增加,晶体的晶格常数和拉曼半高宽都逐渐增大,这说明晶体膨胀和晶格振动模式种类增多。在3at%Yb:Ca_(1-x)La_xF_(2+x)晶体中,当调剂离子La^(3+)掺杂浓度为6at%时,具有最大吸收截面0.71×10-20 cm^2,荧光强度也最大;而在3at%Yb:Ca_(1-x)Gd_xF_(2+x)晶体中,当调剂离子Gd^(3+)掺杂浓度为3at%时,荧光强度最大,Gd^(3+)掺杂浓度为6at%时,具有最大吸收截面0.64×10^(-20) cm^2。共掺晶体相比于单掺3at%Yb:CaF_2晶体有更好的光谱参数。综上可知,通过调节La^(3+)、Gd^(3+)离子浓度,可以改变Yb^(3+)离子的结构,优化晶体的光谱性能。

Pr,R^(3+):SrF_2(R=Y,Gd)激光晶体光谱性能的研究

采用坩埚下降法生长了系列共掺的Pr,Y:SrF_2和Pr,Gd:SrF_2晶体,研究了调剂离子对Pr:SrF_2晶体晶胞参数和光谱性能的影响规律。研究结果表明,掺杂不同种类和浓度的调剂离子可以有效提高晶体的吸收截面和发射强度。同时,调剂离子通过改变晶体内部的团簇构型和发光中心的局域配位结构,使Pr,R^(3+):SrF_2(R=Y,Gd)晶体各峰位的发光强度变化规律不一致:绝大部分峰位发光强度先增加到峰值后减小,极个别变化趋势相反或发光强度基本保持不变。结合晶胞参数和荧光寿命图谱也可以证明调剂离子对晶体内部团簇和局域结构的影响。总之,掺入调剂离子后,Pr:SrF_2晶体的光学性能更优,尤其是共掺入6.0at%Y^(3+)或10.0at%Gd^(3+)后,其光学性能达到最佳。

Modulating absorption band of triangular silver nanoplates in aqueous solvent and on substrates using tannin as reducing agent

Triangular silver nanoplates in aqueous solvent and on the surface of quartz substrate have been synthesized by seed-mediated growth approach in the presence of tannin.It was found that both the amount of tannin and the small triangular silver nanoplate seeds added to the growth solution are the key factors to modulation absorption band of triangular silver nanoplates.The optical in-plane dipole surface plasmon resonance (SPR) bands of these Ag nanoplates can be tuned from 608 nm to 980 nm via tannin deoxidization method.The formation mechanism of triangular silver nanoplates was proposed.The tannin deoxidization method realizes a convenient modulation of the absorption band of Ag nanostructures within the visible near-infrared (IR) region both in aqueous solvent and on substrates under mild conditions.

Orlistat-lnduced Modulation of Plasma Metabolites Independent of Weight Loss in Overweight Females

Orlistat-induced weight loss results in amelioration in several comorbidities including obesity-related dyslipidemia. The aim of the present study was to characterize the changes in the blood plasma metabolic profile from overweight women treated with Orlistat, a lipase inhibitor. A metabonomic approach employing LHNMR was applied to the access metabolic profile in lean and overweight women after a 120 day treatment with 120 mg of Orlistat three times daily. Twenty overweight women （BMI： 32.8 ± 2.9 kg/m2） were evaluated before and after Orlistat treatment and seven normal weight women （BMh 21.8 ± 1.4 kg/m2） were taken as control. After 120 days of treatment with Orlistat, no significant weight changes were observed. However, Orlistat-induced metabolic changes in overweight subjects decreased the profile differences between lean and obese individuals, independent of weight loss. These were associated to decreasing levels of lactate and calcium. Higher levels of lactate, alanine and lipids from overweight subjects were detected in comparison to lean individuals. These results show that a lipase inhibitor shifts the metabolic profile of overweight subjects towards normality, independent of weight loss.

Canonical transient receptor potential 4 and its small molecule modulators

Canonical transient receptor potential 4(TRPC4) forms non-selective cation channels that contribute to phospholipase C-dependent Ca2+ entry into cells following stimulation of G protein coupled receptors and receptor tyrosine kinases.Moreover,the channels are regulated by pertussis toxin-sensitive Gi/o proteins,lipids,and various other signaling mechanisms.TRPC4-containing channels participate in the regulation of a variety of physiological functions,including excitability of both gastrointestinal smooth muscles and brain neurons.This review is to present recent advances in the understanding of physiology and development of small molecular modulators of TRPC4 channels.

Calcium-catalyzed reactions of element-H bonds

Investigation on organocalcium catalysis is just unfolding during the past decade. Beside conventional Ca salts with strong electron-withdrawing counter anions that may serve as Lewis acid catalysts, many Ca complexes have also been designed recently and found to be good catalysts in activation of element-H （E-H） bonds like transition metal catalysts. These findings are interesting and may attract the interest of the chemists. Due to the great abundance, non-toxicity, and biocompatible features of Ca element, Ca-catalyzed reactions can be of great significance from the viewpoint of industry. This short review summarizes the recent advances on Ca-catalyzed reactions of E-H bonds. We hope that it may provide a useful guide for interested readers from both the academy and industry.