Preparation of 17β‐estradiol surface molecularly imprinted polymers and their application to the analysis of biological samples

17β‐Estradiol (E2) surface molecularly imprinted polymers have been prepared using functionalized monodispersed poly(glycidyl methacrylate‐co‐ethylene dimethacrylate) beads as a support. The resulting polymers were found to be uniform in size (5 μm), and the surfaces of the microspheres possessed large pore‐like structures. A chromatographic experiment demonstrated that the resulting microspheres exhibited high levels of recognition and selectivity toward the target molecule. The particles were employed as a novel sorbent in a molecularly imprinted SPE protocol. A method was then developed involving the combination of the pretreatment with HPLC to determine the levels of estrogen secreted from Michigan Cancer Foundation‐7 cells. The obtained results revealed that the extraction recoveries of E2 from real samples were in the range of 73.0–97.5% with RSDs of < 7.5% (n = 3). Calibration curves were established with R values > 0.9996 for concentrations in the range of 0.50–100.00 ng/mL. The LOD of this new method was 0.14 ng/mL. Compared with traditional C₁₈ SPE agents, the particles showed high selectivity and extraction efficiency for E2 in the pretreatment process. The particles could therefore be used to determine trace estrogen in biological samples with a UV detector only.     

Sulfur Precursor Reactivity Affecting the Crystal Phase and Morphology of Cu2−xS Nanoparticles

For plasmonic copper-deficient Cu_2−xS nanoparticles (NPs), accurate control of the crystal phase and morphology is highly desirable as both of which are known to determine the localized surface plasmon resonance (LSPR) wavelength and amplitude. Here, how the sulfur precursor reactivity in the synthesis of Cu_2−xS NPs affects the resulting crystal phase and morphology is examined. Djurleite Cu_1.94S, roxbyite Cu_1.8S, digenite Cu_1.8S as well as covellite CuS nanodisks were synthesized by using 1-dodecanethiol, N,N-dibutylthiourea, and crystal sulfur 1-octadecene/oleylamine solutions and their crystal phase dependent LSPR properties were exhaustively discussed. In addition, crystal phase interconversion between covellite CuS and djurleite/roxbyite Cu_2−xS was realized in the presence of the above sulfur precursors. On the other hand, djurleite Cu_1.94S nanorods rather than nanodisks were prepared by replacing 1-dodecanethiol with more reactive tert-dodecanethiol. The structural and morphological Cu_2−xS NPs here holds great promise in the application of photothermal therapy, photocatalysis, surface-enhanced Raman scattering (SERS), and many others.     

Phase separation dynamics of a poly(vinyl methyl ether)/polystyrene (PVME/PS) blend studied by ultrafast differential scanning calorimetry

In this work, ultrafast differential scanning calorimetry (UFDSC) is used to study the dynamics of phase separation. Taking poly(vinyl methyl ether)/polystyrene (PVME/PS) blend as the example, we firstly obtained the phase diagram that has lower critical solution temperature (LCST), together with the glass transition temperature (T_g) of the homogeneous blend with different composition. Then, the dynamics of the phase separation of the PVME/PS blend with a mass ratio of 7:3 was studied in the time range from milliseconds to hours, by the virtue of small time and spatial resolution that UFDSC offers. The time dependence of the glass transition temperature (T_g) of PVME‐rich phase, shows a distinct change when the annealing temperature (T_a) changes from below to above 385 K. This corresponds to the transition from the nucleation and growth (NG) mechanism to the spinodal decomposition (SD) mechanism, as was verified by morphological and rheometric investigations. For the SD mechanism, the temperature‐dependent composition evolution in PVME‐rich domain was found to follow the Williams–Landel–Ferry (WLF) laws. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 1357–1364     

PAC理论在教学运用中的研究初探

PAC理论作为人际关系心理学中的重要理论,它的＂心态转化原理＂能帮助学生克服人际沟通障碍,＂人际互动类型原理＂能够帮助学生选择解决问题的正确途径,＂P≡P-C≡C交往心态原理＂能使学生有效中断不良交往方式。总体上说,这一理论可以有效促进学生把握心理状态,深入理解问题,从而有助于提升教学效果。     

Hypercoal对不同炼焦煤炭化改质作用的显微镜研究

Hypercoal(HPC)被作为一种添加剂加入到两种性质不同的炼焦煤中,以探讨其对炼焦煤炭化的改质作用。通过偏光显微镜以及扫描电镜观测炭化产物的组织结构变化。结果表明,添加剂的用量以及粒径对炼焦煤炭化改质作用的大小与原料煤的煤质有关,对焦煤改质时要求添加剂颗粒的粒径较大;而对弱黏结性煤改质时,添加剂粒径较小且添加量较多更有利于黏结和熔融作用。通过添加HPC可改善焦煤因过度膨胀造成的不均匀孔隙结构,而且孔的数量与孔径减小,孔壁增厚;添加剂在炭化过程中产生的胶质体促进了弱黏结性煤的黏结和熔融,改善了炭化产物的结构。实验还考察了原料中水分、成型压力等因素对炭化产物结构的影响。结果表明,煤中水分会在炭化产物中产生特殊的孔隙结构,而成型压力对炭化改质作用则因原料煤质不同而不同。     

N-heterocyclic carbene-mediated formal [3+3] annulation of isatin-derived α, β-unsaturated acids: Access to functionalized 3,4′-spirooxindole δ-lactones

An in situ activation of isatin-derived α,β-unsaturated acids 2 for the generation of isatin-derived α,β-unsaturated acyl azoliums II was described. The acyl azoliums II were successfully applied to undergo a formal [3 + 3] annulation with 1,3-dicarbonyl compounds to access functionalized 3,4′-spirooxindole δ-lactones 4. A scale-up synthesis and an enantioselective variant of this protocol were also investigated. The stable and easily prepared acids 2 may be further utilized as promising versatile electrophilic 1,3-synthons for divergent synthesis of spirooxindoles.     

Chemical synthesis and characterization of manganese oxide coated Ni particles

Nanosized Ni particles with an average diameter of about 8 nm were prepared by reducing of NiCl 2 with sodium borohydride (NaBH 4 ) in aqueous solution. By moderate annealing in protective atmosphere, the composite grew up to be 15-20 nm particles. Both of the as-prepared and annealed Ni particles were coated by a layer of manganese oxide via decomposition reaction in aqueous KMnO4 solution. Hysteresis loops of as-prepared samples show a large increase in the magnetization with decreasing temperature and an unsaturated component at high magnetic field. In contrast, the ferromagnetic characteristics of annealed one are much stronger with large magnetization and coercivity. The thermomagnetic curves verified the coexistence of ferromagnetic Ni and antiferromangetic Mn oxide phases. But there exists no exchange bias behavior in the samples, even though the interface structure between the ferromagnetic Ni core and the antiferromagnetic manganese oxides has been distinctly formed. The absence of exchange bias probably originates from the weak ferromagnetic characteristic of Ni cores.     

高校招投标采购的特点

随着高校向现代化教育技术的发展,购买仪器采购数量的增多,尤其是进口设备的采购,对现有的采购程序提出了新的挑战。文中从高校设备购置的特点出发,讨论了市场与竞争、如何选择采购方式、验收的重要意义以及在全过程的监督机制等问题。通过在实际中遇到的各种问题,提出了应该加强政府采购制度建设,改善市场竞争环境,强化设备采购前期调研工作,合理选择设备采购方式等。总结了高校仪器设备招标采购的经验,探讨了高校仪器设备招标采购的规律。     

CD44v6、E-cadherin和ki-67蛋白质与腮腺多形性腺瘤的生物学行为相关性研究

为检测腮腺多形性腺瘤中CD44v6、E-cadherin和ki-67蛋白表达,以探讨其与腮腺多形性腺瘤生物学行为的相关性。应用免疫组织化学SP法染色检测腮腺多形性腺瘤组、多形性腺瘤恶变组和瘤旁非瘤组织组各组间CD44v6、Ecadherin和ki-67蛋白表达。结果显示,(1)CD44v6、E-cadherin和ki-67在腮腺多形性腺瘤组中的阳性表达率分别为100%、96%和73.8%;(2)E-cadherin和ki-67在腮腺多形性腺瘤组、多形性腺瘤恶变组和瘤周非瘤组织间的阳性表达率均有差异,其表达与腮腺多形性腺瘤的浸润转移有关;(3)CD44v6在腮腺多形性腺瘤组与瘤周非瘤组织组,多形性腺瘤恶变组与瘤周非瘤组织组中的表达有统计学差异。由此可知,E-cadherin和ki-67与腮腺多形性腺瘤的生物学行为有关,可作为新的肿瘤标志物,其表达对判断预后有一定的价值。