Analysis of the traditional medicine YiGan San by the fragmentation patterns of cadambine indole alkaloids using HPLC coupled with high‐resolution MS

YiGan San (YGS) has long been used in traditional Japanese and Chinese folk medicine and serves as a potent and novel therapeutic agent to treat Alzheimer's disease. In the present study, a rapid and sensitive method based on HPLC coupled with diode‐array detection and quadrupole TOF MS (Q‐TOF‐MS) was designed to reveal the chemical constituents of YGS. Thirty‐six compounds were identified and assigned in YGS, including 14 alkaloids, nine γ‐lactones, six flavonoids, three triterpenoid saponinares, two small molecular organic acids, and two other types of compounds. In addition, the accurate fragment weight and MS/MS fragmentation reactions of a subtype indole alkaloid in Uncariae ramulus cum uncis were summarized for the first time to realize rapid identification without reference substances. For the first time, 11 major constituents were comprehensively quantified with a HPLC coupled with triple‐quadrupole MS method. A three‐section switch was used to realize such multicomponent identification. The contents of saikosaponin B₂ and isoliquiritin, which produce anti‐inflammatory and antidepressant‐like effects, were extremely different, up to 700 times, in two sources of YGS. The developed qualitative and quantitative method was proved to be precise, accurate, and reproducible.     

36 mW 2抽头40 Gb/s四级脉冲幅度调制发送器的设计

基于SMIC 65-nm CMOS工艺设计了一种40Gb/s低功耗四级脉冲幅度调制(PAM4)发送器。设计中的预加重抽头只在输出信号电平转换后紧跟的单位时间间隔内才向输出节点注入电流。当输出信号不进行电平转换时,电流不流经预加重抽头,解决了现有预加重结构浪费功耗的问题。预加重抽头采用了一种新型的基于可开关电流源的低电压差分信号(LVDS)驱动单元,使得电路可以在高速下消除功耗浪费。电路采用了PAM4调制,降低了带宽的要求。仿真中使用的信道在20GHz的损耗为20.2dB。结果表明,经过预加重,接收端的信号的眼图高度120mV,眼图宽度为30ps。40Gb/s发送器电路的功耗为36mW,能效为0.9pJ/b。     

Preparation and up-conversion luminescence of hollow La2O3:Ln (Ln = Yb/Er, Yb/Ho) microspheres

Hollow La(2)O(3):Ln (Ln = Yb/Er, Yb/Ho) microspheres with up-conversion (UC) luminescence properties were successfully synthesized via a facile sacrificial template method by employing carbon spheres as hard templates followed by a subsequent heating process. The structure, morphology, formation process, and fluorescent properties are well investigated by various techniques. The results indicate that the hollow La(2)O(3):Ln microspheres can be well indexed to the hexagonal La(2)O(3) phase. The hollow La(2)O(3):Ln microspheres with uniform diameter of about 270 nm maintain the spherical morphology and good dispersion of the carbon spheres template. The shell of the hollow microspheres consists of numerous nanocrystals with the thickness of approximately 40 nm. Moreover, the possible formation mechanism of evolution from the carbon spheres to the amorphous precursor and to the final hollow La(2)O(3):Ln microspheres has also been proposed. The Yb/Er and Yb/Ho codoped La(2)O(3) hollow spheres exhibit bright up-conversion luminescence with different colors derived from different activators under the 980 nm NIR laser excitation. Furthermore, the doping concentration of the Yb(3+) is optimized under fixed concentration of Er(3+)/Ho(3+). This material may find potential applications in drug delivery, hydrogen and Li ion storage, and luminescent displays based on the uniform hollow structure, dimension, and UC luminescence properties.     

Photoinduced electron transfer and fluorophore motion as a probe of the conformational dynamics of membrane proteins: application to the influenza a M2 proton channel

The structure and function of the influenza A M2 proton channel have been the subject of intensive investigations in recent years because of their critical role in the life cycle of the influenza virus. Using a truncated version of the M2 proton channel (i.e., M2TM) as a model, here we show that fluctuations in the fluorescence intensity of a dye reporter that arise from both fluorescence quenching via the mechanism of photoinduced electron transfer (PET) by an adjacent tryptophan (Trp) residue and local motions of the dye molecule can be used to probe the conformational dynamics of membrane proteins. Specifically, we find that the dynamics of the conformational transition between the N-terminal open and C-terminal open states of the M2TM channel occur on a timescale of about 500 μs and that the binding of either amantadine or rimantadine does not inhibit the pH-induced structural equilibrium of the channel. These results are consistent with the direct occluding mechanism of inhibition which suggests that the antiviral drugs act by sterically occluding the channel pore.     

A digital image-based method for determining of total acidity in red wines using acid-base titration without indicator

This work proposes the use of digital image-based method for determination of total acidity in red wines by means of acid-base titration without using an external indicator or any pre-treatment of the sample. Digital images present the colour of the emergent radiation which is complementary to the radiation absorbed by anthocyanines present in wines. Anthocyanines change colour depending on the pH of the medium, and from the variation of colour in the images obtained during titration, the end point can be localized with accuracy and precision. RGB-based values were employed to build titration curves, and end points were localized by second derivative curves. The official method recommends potentiometric titration with a NaOH standard solution, and sample dilution until the pH reaches 8.2-8.4. In order to illustrate the feasibility of the proposed method, titrations of ten red wines were carried out. Results were compared with the reference method, and no statistically significant difference was observed between the results by applying the paired t-test at the 95% confidence level. The proposed method yielded more precise results than the official method. This is due to the trivariate nature of the measurements (RGB), associated with digital images.     

Effect of Lead Contamination on Soil Microbial Activity Measured by Microcalorimetry

Microcalorimetry was used to investigate the microbial activity in three types of soil (orchard soil, crop soil, forest soil) in Wuhan, China, and to evaluate the influence of different concentrations of lead (Pb²⁺) on soil microbial activity. The experimental results revealed that due to different physical and chemical characteristics of the soils, soil microbial activity in three soil samples were in a descending sequence: orchards soil, crops soil, forest soil. Six levels of Pb viz. 0, 10, 20, 40, 80, 160 μg·g⁻¹ were applied in these soils, and the results showed that an increase of the amount of Pb²⁺ is associated with a decrease in microbial activity in the soils due to the toxic effect of Pb²⁺. In order to gain further insight of the sequential change of microorganisms, determination of colony forming units (CFU) was performed to provide a negative linear correlation between the heat effect and the respective number of microorganisms in the system.     

Theoretical study of collision and collision-free radiative lifetimes of {{\text{S}}_2}\left( {{{\text{B}}^3}\Sigma_{\text{u}}^{-} \left( {{\upsilon^{\prime}} = 0 - 9} \right)} \right)

We calculate multireference configuration-interaction wavefunctions and the potential-energy curves for the $ {B^3}\Sigma_u^{-} $ and $ {X^3}\Sigma_g^{-} $ states of the collision-free S₂ molecule and the T-shape collision complex S₂?CHe using cc-pVQZ basis sets. We obtain the transition dipole moments of the $ {{\text{S}}_2}\left( {{B^3}\Sigma_u^{-} \to {X^3}\Sigma_g^{-} } \right) $ and the Franck?CCondon factors between the vibrational levels of this two states. We evaluate the radiative lifetimes of $ {{\text{S}}_2}\left( {{B^3}\Sigma_u^{-} \left( {{\upsilon^{\prime}} = 0 - 9} \right)} \right) $ levels of the collision complex and the collision-free molecule and compare them with the experiments. The collision provides little change in the radiative lifetimes of $ {{\text{S}}_2}\left( {{B^3}\Sigma_u^{-} \left( {{\upsilon^{\prime}} = 0 - 9} \right)} \right) $ according to the previous calculations. We obtain excellent agreement between the theoretical results and the experiments. The data calculated are very useful in the study of the microwave-driven high-pressure sulfur lamp and an S₂ laser pumped by a transverse fast discharge.     

高温高压处理对褐色CVD钻石谱学特征的影响

目前CVD法合成单晶钻石是超硬材料科学和宝石学关注的热点之一,该方法合成的单晶钻石常带有褐色调。通常采用高温高压法（HPHT）提高褐色CVD钻石的色级和透明度,在前期HPHT处理褐色CVD钻石实验基础上,选出颜色改善明显的三颗样品,对其处理前后谱学特征进行对比。采用紫外-可见吸收光谱、红外光谱、光致发光光谱、三维荧光光谱、激光拉曼光谱以及X射线摇摆曲线进行分析。结果表明,褐色和深褐色样品褪色温度较高,处理后样品紫外-可见吸收光谱吸收系数明显减小,透明度明显提高。样品中红外与近红外光谱显示,在1 332 cm-1处的吸收峰与N+中心有关,该中心是褐色CVD钻石常见特征。在3 124 cm-1处吸收峰与NVH0缺陷中心有关,该峰在CVD钻石和HPHT处理钻石中常见。另外在2 700~3 200 cm-1范围变化的一组吸收峰,与C-H键伸缩振动有关。高温对CVD钻石含H基团影响较大,在5~6 GPa压力下处理温度在1 500~1 700 ℃范围,会在近红外波段4 673,6 352,7 354,7 540,7 804和8 535 cm-1出现一组吸收峰,可指示样品经过较高温度处理。目前针对CVD钻石以及经过HPHT处理的CVD钻石近红外波段的论述较少,该研究可以为鉴定CVD钻石及HPHT处理CVD钻石提供依据。综合光致发光光谱和三维荧光光谱分析,处理后样品NV-缺陷比例减小,SiV-中心缺陷比例增加。在5~6 GPa压力下,仅当处理温度高于1 500 ℃时,样品三维荧光光谱在λ_ex/λ_em=500 nm/575 nm处荧光峰增强,在λ_ex/λ_em=490 nm/550 nm处荧光峰消失,从某种意义上该峰位变化可指示样品经过较高温度处理。物相分析结果显示,HPHT处理后CVD钻石在1 332 cm-1处拉曼位移半高宽和XRD摇摆曲线半高宽均减小,表现出了较好的一致性,说明经HPHT处理的褐色CVD钻石结晶质量变优。     

微流控芯片上的红细胞电泳淌度研究

以单细胞成像法分别测量了 3组无农药含水质净化剂、有农药无水质净化剂及其有农药有水质净化剂处理后的杂交鲤鱼红细胞在塑料 ( polymethalmethacrylate ,PMMA)微流控芯片上的电泳淌度。其值分别为 1.138× 10 -4、0 .12 79× 10 -4和 - 0 .85 2 0× 10 -4cm2 v-1s-1。从电泳淌度的差别可以看出功夫菊酯和水质条件恶化均可使鲤鱼红细胞表面的电荷密度发生变化 ,从而引起电泳淌度的变化。同时还初步考察了细胞电泳淌度作为参数进行细胞分类的可行性 ,显示这种淌度差别有可能作为细胞分类的一项依据     

一种新的快速解相位方法

提出了一种快速可靠的4步相移编码-解相位算法。通过对中心条纹的光强进行摄动,将编码信息加入到基本相移光栅中,使4幅基本相移图不但包含了相位场主值信息,还包含了解相位所需的编码信息。建立了摄动度函数描述相移图的摄动信息进而得到编码信息,解出完整的相位值。对摄动度函数的误差和噪声进行分析,提出方向滤波方法来消除噪声,极大地减少了编码信息的误判情况。仿真和实验证实了本算法的可行性。与传统相移法相比,解相位的速度和可靠性得到明显的提高。