溶剂热法制备石墨烯/SnO2及其气敏性

采用溶剂热法制备了石墨烯/SnO_2(G/SnO_2)纳米材料,利用扫描电子显微镜(SEM)、X射线衍射(XRD)、拉曼光谱(Raman)等对G/SnO_2进行了表征,研究了石墨烯的量和溶剂热温度对该纳米材料气敏性能的影响。实验结果表明,石墨烯可以调节SnO_2晶体的生长:当石墨烯上清液的量为1 mL、热处理温度为160℃时,制备的G/SnO_2纳米材料在室温下对氨气具有较好的气敏选择性和较高的灵敏度;且当气体体积浓度为1 000μL·L~(-1)时,对NH3的灵敏度为266.4,检出限达到了0.01μL·L~(-1)。     

新型咔唑基半胱氨酸双光子荧光探针的合成及光学性能

以咔唑为母体，设计并合成了一种可检测半胱氨酸的新型双光子荧光探针（3），其结构经¹H NMR, ¹³C NMR, HR-MS(ESI)和元素分析表征。采用UV-Vis和FL研究了3的光学性能。结果表明：半胱氨酸加量为0~50 eq.时，3的紫外最大吸收峰从365 nm蓝移至342 nm；在350 nm处出现一个等吸收点；在450 nm处的荧光强度增强约23倍。     

New advances in microfluidic flow cytometry

In recent years, researchers are paying the increasing attention to the development of portable microfluidic diagnostic devices including microfluidic flow cytometry for the point‐of‐care testing. Microfluidic flow cytometry, where microfluidics and flow cytometry work together to realize novel functionalities on the microchip, provides a powerful tool for measuring the multiple characteristics of biological samples. The development of a portable, low‐cost, and compact flow cytometer can benefit the health care in underserved areas such as Africa or Asia. In this article, we review recent advancements of microfluidics including sample pumping, focusing and sorting, novel detection approaches, and data analysis in the field of flow cytometry. The challenge of microfluidic flow cytometry is also examined briefly.     

在线氧化分光光度法测定铁的价态

1 引言铁的价态影响着铁在生态系统中的迁移性、生物可利用性以及毒性.本研究基于Fe3+与钛铁试剂在酸性条件下生成蓝紫色络合物的反应原理,建立了顺序注射在线氧化测定铁的价态的光度分析方法.     

A new dicaffeoyl quinic acid from Nannoglottis ravida

<正>A new dicaffeoyl quinic acid,nannoglottisin A,has been isolated from an endemic plant of Nannoglottis ravida,and the structure of the compound was identified by means of spectroscopic analysis.     

大鼠服用朱砂后脑内氨基酸类递质含量的变化

研究了朱砂对大鼠脑组织中氨基酸类神经递质含量的影响.将32只Wistar大鼠随机分为低、中、高剂量组和对照组,朱砂灌胃给药14天后,采用高效液相色谱法测定大鼠脑组织中谷氨酸(Glu)、天门冬氨酸(Asp)、甘氨酸(Gly)、γ-氨基丁酸(GABA)和牛磺酸(Tau)的含量,并计算兴奋毒性指数(EI)的变化.与对照组相比较,脑组织中氨基酸类神经递质含量均呈下降趋势,其中Asp和Gly的中、高剂量组差异有统计学意义(P0.05),Tau和GABA的高剂量组有统计学差异(P0.05),Glu和EI所有剂量组均有统计学差异(P0.05).朱砂对氨基酸类神经递质具有一定的抑制作用.     

Synthesis of (-)-calicoferol B

The first total synthesis of (-)-calicoferol B (III) is described. The cyclozirconation product I, prepared in enantiomerically pure form, was converted into the CD ring chiron II. This was coupled with the aromatic A-ring, and then the side chain was constructed with control of relative and absolute configuration to complete the total synthesis of III. The first total synthesis of (-)-calicoferol B (1) is described. The cyclozirconation product 8, prepared in enantiomerically pure form, was converted into the CD ring chiron 6. This was coupled with the aromatic A-ring, and then the side chain was constructed with control of relative and absolute configuration to complete the total synthesis of 1.     

A Two-dimensional Lanthanide Coordination Framework with a New Amide-type Tripodal Ligand, 2,2′,2＂-Nitrilotris{[（2′- benzylaminoformyl）phenoxy]ethyl}amine

The La(III) complex with a new amide‐type tripodal ligand,2,2′.2″‐nitrilotris{[(2′‐benzylaminofomyl)‐phenoxylethyl)amine (L), was synthesized and characterized by X‐ray crystallographic analysis. Crystal data: C₄₈H_55.50LaN₇O_18.75, M_r=1169.40, monoclinic. space group, P2₁/n, a= 1.0644(3) nm. b=2.3889(5) nm, c= 2.1917(5) nm, β=90.65°, V=5.573(2) nm³, Z=1, D_c=1.394 g°cm^?3, R₁=0.0487, wR [1>2s?(I)]=0.1266. The results reveal that each La(III) ion binds to 9 oxygen atoms, three of which belong to carbonyl groups from three tripodal ligands and six to three bidentate nitrate groups and a two‐dimensional sheet of 4.8² networks is assembled by metal‐ligand coordination interaction. L, a heptadentate compound, merely acts as a tridentate bridging spacer due to its steric hindrance and links the La(III) ions as three‐connected nodes.     

Structure and Thermal Stability of a Novel 2‐D Layered Copper(II) Coordination Polymer with the Bidentate Ligand 1, 2, 4‐Triazol‐5‐one

Single crystals of {[Cu(TO)₂(H₂O)₂](NO₃)₂}_n (TO: 1, 2, 4‐triazol‐5‐one) were grown by slow evaporation from aqueous solution. It crystallizes in the orthorhombic space group Pbca, with a = 7.082(1), b = 10.285(1), c = 17.911(3)Å, V = 1304.6(3)ų, Z = 4. The Cu^II distorted octahedra are bridged by bidentate TO ligands into infinite 2‐D interlaced rhombic grid‐like network planes, {[Cu(TO)₂(H₂O)₂]²⁺}_n. Hydrogen bonds, electrostatic interactions, and weak van der Waals' forces assemble these planes and the NO₃^— anions to a layered structure. The title compound decomposes at 153.4 °C to the final products, Cu(CN)₂ and CuO.     

Elucidation of stabilizing pickering emulsion with jackfruit filum pectin-soy protein nanoparticles obtained by photocatalysis

There is still the dearth of reports of jackfruit filum pectin-based nanoparticles as the Pickering emulsifiers with respect to the applications in foods, cosmetics and medicines. So we fabricated soy protein-jackfruit filum pectin nanoparticles (SPP) by photocatalysis as Pickering emulsifier. Jackfruit filum pectin exhibited lower yield (17.31%), degree of methoxylation (15.53%), but higher galacuronic acid content (74.22%). A strong linkage between pectin and soy protein was formed by photocatalysis. The conjugated polymer could self-assemble into compact near globular nanoparticle. The mean size of SPP was larger than that of soy protein nanoparticles but smaller than that of soy protein-pectin complex without photocatalysis. Besides, the zeta potential of SPP was ?33.8?mV, significantly lower than that of soy protein nanoparticles but higher than that of control sample, further confirming that SPP surfaces were completely covered with pectin molecules. Compared with control sample, the three-phase contact angle increased from 42.7 to 90.6°, indicated that SPP could be developed as effective Pickering emulsifiers. The emulsions stabilized by SPP exhibited high thermal stability and excellent salt tolerance as well as good freeze-thaw stability in comparison with emulsions covered with control sample. These findings would provide a potential way of producing effective Pickering emulsifier.GRAPHICAL ABSTRACT