Lipid diffusion in giant unilamellar vesicles is more than 2 times faster than in supported phospholipid bilayers under identical conditions

The lateral diffusion coefficients of a BODIPY tail-labeled lipid in two model systems, namely, free-standing giant unilamellar vesicles (GUVs) and supported phospholipid bilayers (SPBs), were determined by fluorescence correlation spectroscopy (FCS) using the Z-scan approach. For the first time, the performed measurements on 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) bilayers maintain exactly the same experimental conditions for both systems, which allows for a quantitative comparison of lipid diffusion in these two commonly used model membranes. The results obtained revealed that the lipid mobility in free-standing bilayers (D=7.8+/-0.8 microm2 s-1) is significantly higher than in the bilayer created on the solid support (mica) (D=3.1+/-0.3 microm2 s-1).     

Simple analysis of four bisphosphonates simultaneously by reverse phase liquid chromatography using n-amylamine as volatile ion-pairing agent

Volatile organic amine was used as the mobile phase addictive during the separation of four bisphosphonates (alendronate, pamidronate, zoledronic acid and etidronate). An isocratic liquid chromatography method with evaporative light-scattering detection (ELSD) was developed for these bisphosphonates which are not retained on non-polar column and lack chromophore for detection. The analytes have sufficiently separated from each other on a Phenomenex C18 column. The effects of mobile phase composition and instrumental parameters of ELSD were studied. This newly developed method enables direct measurement for analysis of bisphosphonates without the need of derivatization. This developed method provides high separation and specificity to bisphosphonate analysis. In quantitative analysis, the method showed satisfactory precision (less than 2.8%) and accuracy (higher than 94.4%), good linearity (r=0.9991-0.9997) and sufficient sensitivity (15-18 microg/ml). It can be easily and conveniently adopted for the routine quality control analysis.     

Hydrothermal synthesis and characterization of the first 1-D indiumphosphate chain In2(HPO4)2(H2PO4)2F2·C4N2H12, a precursor for high dimensional structures

The first one-dimensional (1-D) indiumphosphate chain, In₂(HPO₄)₂(H₂PO₄)₂F₂·C₄N₂H₁₂ (1), has been hydrothermally prepared using piperazine (PIP) as a template. The structure consists of infinite chains of trans,trans-corners-sharing InO₄F₂ octahedra with the adjacent octahedra being bridged by tetrahedral PO₃(OH) and PO₂(OH)₂ units, which are H-bonded with amine groups of the organic cations. Interestingly, this macroanionic chain InP₂O₈H₃F⁻ is similar to that found in the mineral tancoite-like chains and has potential to further set up higher-dimensional networks. On heating 1 in the presence of additional phosphoric acid at 180 °C under hydrothermal condition, compound 2, In₂(OH)(H₂O)(PO₄)₂·H₃O·H₂O, possessed a 3-D structure building from the repetition of a secondary building unit is obtained. When 1 is heated with additional PIP, an unknown phase, compound 3 is formed. Finally, on treatment with another amine, such as diethylenetriamine or 1,4-diaminobutane, at 180 °C, 1, as a precursor, can convert into a previously known 3-D framework structure with 16-membered ring compound 4. Compounds 1 and 2 are determined by single-crystal X-ray diffraction. Furthermore, 1 is characterized by X-ray powder diffraction, IR spectroscopy, inductively coupled plasma analysis, thermogravimetric analysis and differential thermal analysis.     

Neutrino Production via e-e+ Collision at Z-Boson Peak

The production of the three normal neutrinos via e^-e⁺ collision at Z-boson peak (neutrino production in a Z-factory) is investigated thoroughly. The differences of v_e-pair production from v_μ-pair and v_τ-pair production are presented in various aspects. Namely the total cross sections, relevant differential cross sections and the forward-backward asymmetry etc. for these neutrinos are presented in terms of figures as well as numerical tables. The restriction on the room for the mixing of the three species of light neutrinos with possible externals (heavy neutral leptons and/or sterile neutrinos) from refined measurements of the invisible width of Z-boson is discussed.     

CCD与CMOS像素传感器γ射线电离辐射响应特性对比研究

为了研究CCD与CMOS像素传感器对γ射线电离辐射的响应差异,对比研究了4类像素传感器的结构特点和辐射响应特性。通过辐射实验,对各传感器在不同辐射水平条件下的光子响应事件分布、平均灰度值以及典型光子响应事件进行研究。研究结果表明：光子响应程度均与辐射剂量率相关;CCD像素传感器的沟道传输方式使每列像元间的辐射响应更容易相互干扰;平均灰度值随剂量率的增大存在明显的梯度,各积分周期内输出信号灰度值围绕均值上下波动,CCD像素传感器输出信号灰度浮动范围较小;CMOS像素传感器各像元对光子的响应更加明显,CCD像素传感器各像元的响应信号易与相邻像元发生串扰;各类像素传感器典型辐射响应事件区域中发生光子响应的像元数量随剂量率的增大而增多,响应事件并非单个光子的行为,而是反映了多个光子在区域内同时沉积能量的过程。本研究为开发像素传感器的γ射线辐射探测技术和应用提供了重要的理论分析和实验数据支撑。     

高效液相色谱-串联质谱法同时测定供港生猪尿液中29种限用兽药残留

建立了高效液相色谱-串联质谱(HPLC-MS/MS)同时测定生猪尿液中喹诺酮类、磺胺类、磺胺增效剂、四环素类、林可胺类、大环内脂共29种限用兽药残留量的检测方法。试样经乙酸铵和EDTA-Na缓冲液提取,HLB固相萃取小柱净化后,HPLC-MS/MS进行测定,其中β-受体激动剂类用内标法定量,其余兽药用外标法定量。在电喷雾电离正离子模式下,以多反应监测(MRM)方式采集数据进行定性与定量分析。29种兽药在猪尿基质中标准曲线的线性系数(r)均大于0.99,3个不同加标水平下的平均回收率为58%~108%,日内相对标准偏差(RSD)为1.9%~18.9%,日间RSD为3.4%~20.9%;定量下限(LOQ,S/N≥10)为1.0~10.0μg/L。该方法经济、高效、可靠,可用于生猪屠宰前兽药多残留的快速检测。     

新型质子离子液体/硅凝胶电解质的制备及其性能

采用一步溶胶-凝胶法首次将质子型离子液体固定于纳米多孔硅骨架中,合成了表面光滑、柔软、透明的质子增强型固态复合凝胶电解质.研究表明,该凝胶电解质结合了无机硅骨架和质子离子液体的双重优点,具有高的热稳定性（〉300℃）、宽的电化学稳定窗口（〉2.8V）和优异的中低温导电性（11.25×10？3Scm？1,80℃）.可望作为一种新型固态电解质应用于先进储能器件.     

Artanomadimers A–F: six new dimeric guaianolides from Artemisia anomala

A novel dimeric guaianolide with an unprecedented skeleton, named artanomadimer A (1), and five new analogues, artanomadimers B–F (2–6), were isolated from the aerial parts of Artemisia anomala. Their structures and stereochemistry were elucidated by extensive spectroscopic methods, and the absolute stereochemistry of compound 4 was confirmed by X-ray crystallographic analysis. Artanomadimer A (1) is probably formed through a Diels–Alder reaction with the new carbon–carbon bond formation of C-11/C-2′ and C-13/C-5′ based on its structure. A cytotoxic evaluation showed that compounds 1 and 6 exhibited significant inhibitory effects against the cell growth of BGC-823 tumor cell lines with IC₅₀ values of 2.71 and 6.25 μM, respectively.     

Single-step synthesis of layered double hydroxides ultrathin nanosheets

A novel single-step approach was developed to prepare large-scale MgAl-LDHs ultrathin nanosheets. The key point of the successful realization was that we employed a high concentration of H(2)O(2). Oxygen molecules, derived from in situ decomposition of H(2)O(2), were speculated to be the decisive factor leading to complete separation of LDHs layers. The ultrathin nanosheets were characterized by XRD, TEM, AFM, FT-IR, and TG-DSC. The results indicated that the thickness of these nanosheets was about 1.44 nm, which was almost in perfect agreement with the theoretical thickness of two LDHs layers. From the TG-DSC curves, the weight loss of these exfoliated MgAl-LDHs ultrathin nanosheets at 500°C was 18.5%, which was much smaller compared to the 32.3% weight loss of unexfoliated MgAl-LDHs.     

ICP-MS测定血中镁、铜、铅浓度时的基体效应单一内标校正方法研究

ICP-MS测定模拟全血基体中不同质量段的Mg, Cu, Pb元素,考察基体效应对测定值的影响,分别采用传统内标法和单一内标CAIS方法(common analyte internal standardization)对其进行校正和比较。结果表明CAIS方法适用于不同浓度血液基体中多种元素的同时校正,且效果良好,其相对平均误差仅为3.05%,明显低于传统内标法的12.39%和校正前的23.91%;CAIS方法不受内标元素和被测元素质量数差异、测定强度差异以及电极电位差异的限制;使用全血和血清标准物质对CAIS方法可靠性进行验证,测定值全部落在标准值范围内。