用双表面活性剂为共模板合成中孔分子筛MCM-48

利用水热法以非离子表面活性剂聚乙二醇辛基苯基醚和阳离子表面活性剂十六烷基三甲基溴化铵为共模板合成了中孔分子筛MCM-48.实验中发现利用较强的范德华力和氢键,聚乙二醇辛基苯基醚可在很大程度上降低合成MCM-48所需阳离子表面活性剂的用量,且利于制备有序性好、骨架聚合度高、稳定性好的MCM-48.通过调节聚乙二醇辛基苯基醚与十六烷基三甲基溴化铵的比例,可得到不同物相结构的分子筛.     

芳亚甲基丙二腈、芳亚甲基氰乙酰胺的固相合成

芳醛和丙二腈、氰乙酰胺在NH4Ac催化下经固相反应高产率的得到芳亚甲基丙 二腈和芳亚甲基氰乙酰胺。     

Assessment of intermolecular interactions at three sites of the arylalkyne in phenylacetylene‐containing lithium‐bonded complexes: Ab initio and QTAIM studies

The intermolecular interactions existing at three different sites between phenylacetylene and LiX (X = OH, NH₂, F, Cl, Br, CN, NC) have been investigated by means of second‐order Møller?Plesset perturbation theory (MP2) calculations and quantum theory of “atoms in molecules” (QTAIM) studies. At each site, the lithium‐bonding interactions with electron‐withdrawing groups (? F, ? Cl, ? Br, ? CN, ? NC) were found to be stronger than those with electron‐donating groups (? OH and ? NH₂). Molecular graphs of C₆H₅C?CH···LiF and πC₆H₅C?CH···LiF show the same connectional positions, and the electron densities at the lithium bond critical points (BCPs) of the πC₆H₅C?CH···LiF complexes are distinctly higher than those of the σC₆H₅C?CH···LiF complexes, indicating that the intermolecular interactions in the C₆H₅C?CH···LiX complexes can be mainly attributed to the π‐type interaction. QTAIM studies have shown that these lithium‐bond interactions display the characteristics of “closed‐shell” noncovalent interactions, and the molecular formation density difference indicates that electron transfer plays an important role in the formation of the lithium bond. For each site, linear relationships have been found between the topological properties at the BCP (the electron density ρ_b, its Laplacian ?²ρ_b, and the eigenvalue λ₃ of the Hessian matrix) and the lithium bond length d(Li‐bond). The shorter the lithium bond length d(Li‐bond), the larger ρ_b, and the stronger the π···Li bond. The shorter d(Li‐bond), the larger ?²ρ_b, and the greater the electrostatic character of the π···Li bond. © 2012 Wiley Periodicals, Inc.     

Probing the Adhesion of Hepatocellular Carcinoma HepG2 and SK‐Hep‐1 Cells

Carcinoma cell differentiation stage is an important indicator of cell behavior. For example, cell mobility is much higher for poorly‐differentiated hepatocellular carcinoma SK‐Hep‐1 cells than for well‐differentiated HepG2 cells. In this study, we have cultured HepG2 and SK‐Hep‐1 cells on chemically patterned polydimethylsiloxane (PDMS) substrates to observe differences in the adhesion properties and cell structure that occur due to the patterns. Both cell lines showed a preference for the hydrophobic regions on the patterned PDMS surface with SK‐Hep‐1 cells achieving a higher density than HepG2 for the same cell‐count solutions. Further, SK‐Hep‐1 cells adopted the square or hexagonal shape of the surface patterns while HepG2 cells maintained their more rounded shape. AFM force measurement arrays were also performed on the cell surfaces to measure and map adhesion values between the tip and cell surface membrane. These results demonstrate that, in addition to cell shape and size, adhesion expression in hepatocellular carcinoma cells is differentiation stage dependent. Further, the ability of the SK‐Hep‐1 cells to adopt the shape of the substrate pattern indicates they are more structurally labile, which may contribute to their higher mobility.     

Theoretical study on the one‐, two‐, and three‐photon absorption properties of exohedral functionalized derivative of Sc3N@C80

Geometrical structures of three investigated molecules Sc₃N@C₈₀, Sc₃N@C₈₀‐Fc, and C₆₀‐Fc were optimized by density functional theory (DFT) at the B3LYP/6‐31G* level. Then the time‐dependent DFT was employed to investigate the excited states of these molecules. After exohedral functionalization by ferrocene (Fc‐) group as the electron donor or replacing C₆₀ with Sc₃N@C₈₀ as the electron acceptor, the wavelengths of the first one‐photon absorption peak and the strongest two‐photon absorption (2PA) and three‐photon absorption (3PA) peaks shift red. The corresponding cross sections of Sc₃N@C₈₀‐Fc in the 2PA and 3PA processes increase as compared with those of Sc₃N@C₈₀, which originate from the contributions of charge transfers from Fc‐ group to C₈₀ cage and simultaneously the transfers from the C₈₀ cage to the encapsulated Sc₃N cluster. When compared with C₆₀‐Fc, the 2PA and 3PA cross sections of Sc₃N@C₈₀‐Fc decrease, which may result from the more negative charge surface of C₈₀ cage in Sc₃N@C₈₀‐Fc molecule which blocks the charge transfers from Fc‐ moiety to the C₈₀ cage in the excitation processes by compared with C₆₀‐Fc. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012     

Surface characteristics of Ti‐10Ta‐10Nb alloy modified by hydrogen peroxide treatment for dental implants

The use of titanium‐based alloys as biomaterials is becoming more common because they have a reduced elastic modulus, superior biocompatibility, specific strength, good corrosion resistance, superior strain control, and fatigue resistance compared to conventional stainless steel and Co? Cr alloys. However, when implanted into the human body these metals are problematic because they do not directly bond with living bone. Surface treatments play an important role in nucleating calcium phosphate deposition on a surgical titanium alloy implant. The purpose of this study is to examine whether the precipitation of apatite on Ti? 10Ta? 10Nb alloy is affected by surface modification in H₂O₂ solution. Specimens were chemically treated with a solution containing 30 wt% H₂O₂ at 80 °C for 1 h, and subsequently heat treated at 400 °C for 1 h. All specimens were immersed in SBF (Simulated Body Fluid) with a pH of 7.4 at 36.5 °C for seven days, and the surfaces were examined with XRD, SEM, EDX and in vitro testing. The microstructure analysis of the Ti? 10Ta? 10Nb alloy after etching with Keller's etchant showed a Widmanstatten pattern. The micro‐Vickers hardness number was 236.44 ± 4.99, and surface roughness was increased by the surface treatment. The wettability after surface treatment was better than on the nontreated surface. Resistance to cytotoxicity was decreased by the chemical surface treatment (P < 0.05). Copyright © 2011 John Wiley & Sons, Ltd.     

Quantitative analysis of an organic thin film by XPS,AFM and FT‐IR

We report the characterization of Firpic (iridium(III)bis[4,6‐di‐fluorophenyl]‐pyridinato‐N,C²,]picolinate) organic thin film prepared by vacuum deposition to provide a systematic route to organic film quantification. To analyze the characteristics of thin Firpic films on a Si substrate, various techniques such as XPS, Fourier transform infra‐red (FT‐IR) spectrometer, and atomic force microscopy (AFM) are utilized. The Firpic films remain stable without surface morphological or compositional change during deposition and after exposure to X‐ray irradiation or atmospheric environment, for which qualities these films are believed to be an ideal platform as a pure organic thin film. The monotonic increases in FT‐IR and XPS intensities with film thickness are matching well with each other. In particular, from the XPS intensity analysis, the relative atomic sensitivity factors of the present system, electron attenuation length, and molecular density in the organic thin film can be evaluated. Copyright © 2011 John Wiley & Sons, Ltd.     

Studies on the interactions between anionic surfactants and polyvinylpyrrolidone: Surface tension measurement, 13C NMR and ESR

 The interaction between anionic surfactants and polyvinylpyrrolidone (PVP) are investigated using ¹³C NMR, ESR spectroscopy and surface tension measurements at the air/water interface. The behavior of single-chained surfactant, sodium dodecyl sulphonate (AS), is compared with that of the double-chained surfactant, sodium bis(2-ethylhexyl) phosphate (NaDEHP). The results showed that a surfactant–polymer complex of “necklace and head structure” is formed in AS aqueous solutions in the presence of PVP due to the hydrophobic interaction between PVP and AS. The AS micelles nucleate on the polymer hydrophobic sites, and the mobility of the AS head groups is not affected. But, for NaDEHP surfactant, it was found that PVP is little effective in influencing the monomer–micelle equilibrium and no surfactant– polymer complex formed in the NaDEHP aqueous solution. Received: 8 May 1996 Accepted: 14 August 1997