高速逆流色谱法对独角莲中有效成分皂苷的分离纯化

本文采用高速逆流色谱法对独角莲中的有效成分皂苷进行分离纯化.分别以乙酸乙酯∶正丁醇∶乙腈∶水=5∶1∶1∶5(V/V)及乙酸乙酯∶正丁醇∶乙醇∶水=5∶10∶2∶20(V/V)为溶剂系统,用下相作流动相,上相作固定相,分别采用2 mL/min及1.5 mL/min 的流动相流速、800 r/min的转速对独角莲中的有效成分皂苷进行分离,得到纯度98%的胡萝卜苷6 mg.     

Characterization of catechol 1,2-dioxygenase from cell extracts of <Emphasis Type="Italic">Sphingomonas xenophaga</Emphasis> QYY

Sphingomonas xenophaga QYY, capable of growing significantly on more than ten kinds of aromatic compounds as sole carbon source, was used to study characterization of catechol 1,2-dioxygenase (C12O) in cell extracts. Characterization of the crude C12O showed that the maximum activity was obtained at 40–70°C and pH 7.8–8.8. Metal ions had different influences on the activity of crude C12O. It was suggested that strain QYY possessed an inducible and ferric-dependent C12O. Kinetic studies showed that the value of V _max and K _m was 0.25 μmol catechol/L/mg protein/min and 52.85 μmol/L, respectively. In addition, the partial purification of C12O was achieved by a HiTrap Q Sepharose column chromatography. Supported by the National Natural Science Foundation of China (Grant No. 50608011) and the 39th Postdoctoral Funds of China (Grant No. 20060390983)     

直射太阳光差分吸收光谱反演NO2整层垂直柱浓度

在直射太阳光差分吸收光谱技术(DS-DOAS)中,通常采用测量期间较干净大气条件下太阳天顶角最小时的测量谱作为参考谱反演整层垂直柱浓度(VCD)。由于参考谱中依然含有未知的NO2吸收结构,因此得到的是VCD的相对值。该文将大气外层高精度太阳夫琅禾费标准光谱与仪器函数卷积后作为参考谱,避免了参考谱中含有NO2的吸收结构引入的误差。通过研究3月7日用此新方法获得的斜柱浓度(SCD)与通常方法获得的差分斜柱浓度(dSCD)的比较,新方法反演SCD的误差小于1.6×1016 molecules.cm-2;通常方法反演SCD的误差在4.25×1016 molecules.cm-2附近,采用新方法误差减少了62%以上。最后将DS-DOAS测量的NO2整层VCD与多轴差分吸收光谱技术(MAX-DOAS)测得的NO2对流层VCD进行了对比,结果表明新方法可以有效的改进通常方法计算VCD的误差。     

Self-powered solar-blind photodiodes based on EFG-grown(100)-dominant β-Ga2O3 substrate

We report the edge-defined-film-fed(EFG)-grown β-Ga₂O₃-based Schottky photodiodes.The device has a reverse leakage current of ~nA and a rectified ratio of ~10⁴ at ±5 V.In addition,the photodiode detector shows a dark current of 0.3 pA,a photo-responsivity(R) of 2.875 mA/W,a special detectivity(D*) of 10¹⁰ Jones,and an external quantum efficiency(EQE) of 1.4% at zero bias,illustrating a self-powered operation.This work may advance the development of the Ga₂O₃-based Schottky diode solar-blind photodetectors.     

AHNAK Contributes to Hepatocellular Carcinoma Growth by Interacting with IGF-1R

Neuroblast differentiation-associated protein AHNAK, a large structural scaffold protein, remains mysterious in biological processes. AHNAK plays a suppressive or progressive role in different types of cancers. To investigate the role of the AHNAK in hepatocellular carcinoma (HCC), cell viability assays were performed to determine the cell proliferation of the stable AHNAK-knockdown HepG2 cell line; co-immunoprecipitation (Co-IP) and liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) were performed on HCC and matched paracancerous (MPC) tissues. The Metascape platform was used for enrichment analyses; the “ComplexHeatmap” package was applied for cluster analyses and visualization. Co-IP, Western botting and immunofluorescence double staining were performed to assess the interactions between AHNAK and insulin-like growth factor 1 receptor (IGF-1R). AHNAK silencing reduced the viability of HepG2 cells; the interactome in HCC and MPC tissues enriched 204 pathways and processes, which partially reflected the signature of HCC field cancerization. AHNAK could co-localize and interact with IGF-1R. These results suggested that the AHNAK complex contributes to HCC growth, potentially by interacting with IGF-1R.     

大口径标准镜绝对面形精度传递方法

提出了一种大口径干涉仪标准镜绝对面形精度的传递方法,在已知一台干涉仪参考镜绝对面形的前提下,可向待测标准镜进行精度传递。由于检测温度与使用温度的不同,待测标准镜在另一台干涉仪作参考镜时,绝对面形会发生变化,变化集中在离焦量上;在待测标准镜使用状态下,通过对经典三板互检法得到的竖直方向直线绝对面形的分析,得到标准镜使用状态离焦量的估计,以此修正直接精度传递结果,最终得到待测标准镜使用状态下的绝对面形。比较同一块光学元件在两台干涉仪上标定前和标定后的测量结果,标定后的面形差值更小且分布一致性更好,证明了本方法的有效性和可行性。     

多轴差分吸收光谱技术对冬季大气HONO垂直分布特征研究

HONO作为大气OH自由基的前体物和重要贡献源,影响着大气中污染物的氧化降解,控制着对流层大气的自净能力,对灰霾和光化学烟雾形成起到重要作用,同时受污染排放特征、垂直传输和混合、非均相反应和大气光氧化等影响,HONO具有明显的垂直分布特征,因此探究大气中HONO的垂直分布特征对于了解大气灰霾和光化学污染的形成和控制都十分重要。MAX-DOAS作为一种被动遥感技术,能够快速有效地获取大气中污染物的立体分布特征。采用MAX-DOAS仪器对合肥市科学岛2017年12月冬季大气HONO和NO₂进行了立体探测,通过基于最优估算的气溶胶和痕量气体廓线反演算法PriAM获取了两种气体的垂直分布特征。研究结果表明,在观测期间NO₂在近地面10 m内体积混合比（VMR）和垂直柱浓度(VCD)的范围分别在0.51×1011～20.5×1011 molecules·cm-3和6.0×1015～5.5×1016 molecules·cm-2,在垂直方向上其浓度主要集中在1 km内,且在近地面浓度混合均匀。HONO的VMR和VCD分别在0.03×1010～5.1×1010 molecules·cm-3和3.5×1014～7.0×1015 molecules·cm-2之间,浓度高值出现在100 m内,浓度随高度的升高而明显下降。通过对HONO和NO₂的对比发现,HONO/NO₂比值在0.17%～16.0%（VMR）和1.0%～25.0%(VCD)之间,表明研究期间HONO主要来自于NO₂的转化。对冬季一次典型污染过程（2017.12.26—2017.12.31）分析,HONO/NO₂的比值大于5%,且HONO的浓度值升高（大于0.26×1011 molecules·cm-3）,表明污染条件下NO₂向HONO的转化作用变强。结合风场信息研究发现,污染期间研究区域的NO₂和HONO浓度受到合肥市城区、安徽北部和西北部地区传输的影响。     

222Rn radioactivity in urban waters of fault zone in China: dose rate and risk assessment

Journal of Radioanalytical and Nuclear Chemistry - The exhalation of radon from waters surrounding active fault zones is at present not well understood. In this work, radon concentrations in urban...     

Continuous-Wave Raman Lasing from Metal-Linked Organic Dimer Microcrystals

Stimulated Raman scattering offers an alternative strategy to explore continuous-wave (c.w.) organic lasers, which, however, still suffers from the limitation of inadequate Raman gain in organic material systems. Here we propose a metal-linking approach to enhance the Raman gain of organic molecules. Self-assembled microcrystals of the metal linked organic dimers exhibit large Raman gain, therefore allowing for c.w. Raman lasing. Furthermore, broadband tunable Raman lasing is achieved in the organic dimer microcrystals by adjusting excitation wavelengths. This work advances the understanding of Raman gain in organic molecules, paving a way for the design of c.w. organic lasers.     

Evaluation of an electrochemical sensor based on gold nanoparticles supported on carbon nanofibers for detection of tartrazine dye

Journal of Solid State Electrochemistry - An electrochemical sensor for the detection of tartrazine (Tz), a synthetic azo dye customarily found in commercial soft drinks, is herein reported. This...