Simultaneous three-photon-excited violet upconversion luminescence of Ce3+:Lu2Si2O7 single crystals by femtosecond laser irradiation

We found that Ce3+:Lu2Si2O7 single crystals could be excited at 800 nm by using a femtosecond Ti:sapphire laser. The emission spectra of Ce3+:Lu2Si2O7 crystals were the same for one-photon excitation at 267 nm as for excitation at 800 nm. The emission intensity of Ce3+:Lu2Si2O7 crystals was found to depend on the cube of the laser power at 800 nm, consistent with simultaneous absorption of three 800 nm photons. The measured value of the three-photon absorption cross section is sigma'3=2.44x10(-77) cm6 s2.     

Hydration-induced far-infrared absorption increase in myoglobin

The interaction of proteins with an aqueous environment leads to a thin region of "biological water", the molecules of which have properties that differ from those of bulk water, in particular, reduced absorption of far-infrared radiation caused by protein-induced hindrance of the water rotational and vibrational degrees of freedom. New results at terahertz (THz) frequencies, however, show that absorption per protein molecule is increased by the presence of biological water. Absorption measurements were made of the heme protein myoglobin mixed with water from 3.6 to 98 wt % in the frequency range of 0.1-1.2 THz, using THz time-domain spectroscopy. Analysis shows greater THz absorption when compared to a non-interacting protein-water model. Including the suppressed absorption of biological water leads to a substantial hydration-dependent increase in absorption per protein molecule over a wide range of concentration and frequencies, meaning that water increases the protein's polarizability.     

龙葵多糖含量测定及组分分析

1引言龙葵(Solanum nigrumL.)属茄科植物,其性寒味苦,具有清热解毒,活血消肿,治疗疮、痈、肿、跌打损伤,龙葵全草在治疗子宫绒毛膜癌、卵巢癌和肝癌等效果显著。多年来工作者从脂溶性成分中分离出龙葵碱,并且从水溶性成分中分离出两种龙葵多糖。本实验主要研究龙葵多糖含量测定     

银(Ⅰ)催化氧化邻甲氧基酚的反应特性及其应用

基于在ＨＡｃ－ＮａＡｃ介质中,以２,２‘－联吡啶为活化剂,银可灵活地催化过硫酸铵与邻甲氧基酚的氧化还原显色反应,研究了反应的最佳条件及动力学参数,并对反应机理作了探讨,从而实现了痕量银的催化动力学光度法测定。     

高效毛细管电泳分析羊栖菜多糖对肿瘤机体红细胞合淌度的影响

为了分析羊栖菜多糖（SFPS）对肿瘤机体红细胞合淌度的影响,建立了肿瘤动物模型,分高、中、低剂量腹腔给予羊栖菜多糖7 d,采集并制备红细胞悬液,应用高效毛细管电泳法检测红细胞的合淌度。实验条件:毛细管为75 μm×50 cm,电泳缓冲液为含2 g/L羟丙基甲基纤维素的磷酸盐溶液(0.1 mol/L,pH 7.4),压力进样为3.448 kPa×10 s,分离电压为20 kV,柱温为25 ℃,电渗淌度为2.16×10-4 cm2·V-1·s-1。实验结果表明：羊栖菜多糖能降低肿瘤机体红细胞的电泳迁移时间(阴性对照组为15.76 min,SFPS低剂量组为13.96 min,SFPS中剂量组为12.90 min,SFPS高剂量组为13.51 min,正常对照组为11.51 min),增加红细胞的合淌度(阴性对照组为1.06×10-4 cm2·V-1·s-1,SFPS低剂量组为1.19×10-4 cm2·V-1·s-1,SFPS中剂量组为1.29×10-4 cm2·V-1·s-1,SFPS高剂量组为1.23×10-4 cm2·V-1·s-1,正常对照组为1.45×10-4 cm2·V-1·s-1),SFPS 3个剂量组红细胞的合淌度与阴性对照组比较均有非常显著的差异(P＜0.01)。羊栖菜多糖能够改变肿瘤机体红细胞的合淌度,并使之趋向于正常机体水平,这可能与其改变红细胞表面的电荷密度有关。高效毛细管电泳法可以作为检测红细胞生理状态和功能的一种辅助工具。     

催化动力学光度法同时测定铜和银

基于Ｃｕ（Ⅱ）、Ａｇ（Ⅰ）在硼酸－氢氧化钠缓冲介质中,能同时催化过硫酸铵氧化邻甲氧基酚的显色反应,实现了Ｃｕ（Ⅱ）、Ａｇ（Ⅰ）的催化动力学分析法同时测定,研究了最佳反应条件,用于合成样品测定时比较了多元线笥回归（ＭＬＲ）、卡尔紧滤波（ＫＦ）和人工神经网络（ＡＮＮ）用于数据处理的优劣,发现以ＡＮＮ法的结果最好。此法用于铅锌矿废渣中铜、银的同时测定,结果满意。     

Comparison of multiple gene assembly methods for metabolic engineering

A universal, rapid DNA assembly method for efficient multigene plasmid construction is important for biological research and for optimizing gene expression in industrial microbes. Three different approaches to achieve this goal were evaluated. These included creating long complementary extensions using a uracil-DNA glycosylase technique, overlap extension polymerase chain reaction, and a SfiI-based ligation method. SfiI ligation was the only successful approach for assembling large DNA fragments that contained repeated homologous regions. In addition, the SfiI method has been improved over a similar, previous published technique so that it is more flexible and does not require polymerase chain reaction to incorporate adaptors. In the present study, Saccharomyces cerevisiae genes TAL1, TKL1, and PYK1 under control of the 6-phosphogluconate dehydrogenase promoter were successfully ligated together using multiple unique SfiI restriction sites. The desired construct was obtained 65% of the time during vector construction using four-piece ligations. The SfiI method consists of three steps: first a SfiI linker vector is constructed, whose multiple cloning site is flanked by two three-base linkers matching the neighboring SfiI linkers on SfiI digestion; second, the linkers are attached to the desired genes by cloning them into SfiI linker vectors; third, the genes flanked by the three-base linkers, are released by SfiI digestion. In the final step, genes of interest are joined together in a simple one-step ligation.     

"三明治夹心"型Ni-P@Ni-B/Ni电极的制备及高效全pH下的催化制氢性能

通过化学镀法制备了具有“三明治夹心”结构的Ni-P@Ni-B/Ni催化电极. 该催化材料为直径1 μm左右的微球. 电化学性能测试结果表明, 在电流密度为10 mA/cm ²时, 其在0.5 mol/L PBS缓冲液(pH=7)中的过电位仅为287 mV, 在此电位下连续工作24 h后, 电流密度仅衰减了7.6%. 同时Ni-P@Ni-B/Ni在酸性(0.5 mol/L H₂SO₄)和碱性(1 mol/L KOH)条件下也具有优异的析氢反应催化活性, 达到相同电流密度时过电位分别为199和79 mV. 该工作为全pH环境下高效电解水制氢提供了新思路.     

基于超滤离心前处理的液相色谱-串联质谱法手性拆分人血浆中的亚叶酸和5-甲基四氢叶酸非对映异构体及其药代动力学应用

建立了液相色谱-串联质谱（HPLC-MS/MS）同时测定人血浆中的亚叶酸和5-甲基四氢叶酸两对非对映异构体的方法。血浆经蛋白质沉淀-超滤离心处理后,以甲氨蝶呤为内标,乙腈-10 mmol/L pH 8.0醋酸铵为流动相,通过手性HSA色谱柱（150 mm×4 mm,5 μm）进行梯度洗脱。亚叶酸非对映异构体在25~5000 μg/L范围内、5-甲基四氢叶酸非对映异构体在12.5~2500 μg/L范围内,线性关系均良好。本方法在灵敏度、精密度、准确度、基质效应、提取回收率、稳定性等方面均得到充分验证,并成功应用于125 mg/m²亚叶酸和62.5 mg/m²左旋亚叶酸的药代动力学研究。结果显示：在125 mg/m²亚叶酸剂量组,左亚叶酸和左旋-5-甲基四氢叶酸的血浆峰浓度（C_max）为（3137.917±408.837）和（1679.633±244.132）μg/L,从时间点0到最后可定量时间点的药物代谢动力学时间曲线下面积（AUC_0-t）为（7504.883±1185.101）和（14001.214±2868.949）μg/L;在62.5 mg/m²左亚叶酸剂量组,左亚叶酸和左旋-5-甲基四氢叶酸的C_max为（3187.917±387.298）和（1739.204±224.755）μg/L,AUC_0-t为（7426.664±854.825）和（14884.331±1843.353）μg/L。两剂量组主要药物代谢动力学参数均无显著差异,特征一致,吸收的速度和程度一致,能够为后期进行左亚叶酸钠生物等效性研究提供技术支持。     

Hierarchical Co‐Assembly Enhanced Direct Ink Writing

Integrating intelligent molecular systems into 3D printing materials and transforming their molecular functions to the macroscale with controlled superstructures will unleash great potential for the development of smart materials. Compared to macromolecular 3D printing materials, self‐assembled small‐molecule‐based 3D printing materials are very rare owing to the difficulties of facilitating 3D printability as well as preserving their molecular functions macroscopically. Herein, we report a general approach for the integration of functional small molecules into 3D printing materials for direct ink writing through the introduction of a supramolecular template. A variety of inorganic and organic small‐molecule‐based inks were 3D‐printed, and their superstructures were refined by post‐printing hierarchical co‐assembly. Through spatial and temporal control of individual molecular events from the nano‐ to the macroscale, fine‐tuned macroscale features were successfully installed in the monoliths.