Poly(N-isopropylacrylamide)-based thermo-responsive surfaces with controllable cell adhesion

Poly(N-isopropylacrylamide) (PNIPAAm)-based thermo-responsive surfaces can switch their wettability (from wettable to non-wettable) and adhesion (from sticky to non-sticky) according to external temperature changes. These smart surfaces with switchable interfacial properties are playing increasingly important roles in a diverse range of biomedical applications; these controlling cell-adhesion behavior has shown great potential for tissue engineering and disease diagnostics. Herein we reviewed the recent progress of research on PNIPAAm-based thermo-responsive surfaces that can dynamically control cell adhesion behavior. The underlying response mechanisms and influencing factors for PNIPAAm-based surfaces to control cell adhesion are described first. Then, PNIPAAm-modified two-dimensional flat surfaces for cell-sheet engineering and PNIPAAm-modified three-dimensional nanostructured surfaces for diagnostics are summarized. We also provide a future perspective for the development of stimuli-responsive surfaces.     

Enhanced monopole transition strength from the cluster decay of ~(13)C

The inelastic excitations and cluster decay of ~(13)C have been measured using the reaction,9Be(~(13)C, ~(13)C* →~9Be + α)~9Be. We observe strong excitation to the 14.3-MeV(1/2-) resonant state from the cluster-decay channel, leading to an enhanced monopole matrix element of(6.3 ± 0.6) fm~2. This large cluster-related monopole strength is a clear indication of the cluster-structure domination of this state and is consistent with the recent prediction of the orthogonality condition model(OCM). It would be interesting to further explore the three-center molecular rotational band that is initiated from the observed band-head.     

High-lying excited states in <Superscript>10</Superscript>Be from the <Superscript>9</Superscript>Be(<Superscript>9</Superscript>Be,<Superscript>10</Superscript>Be)<Superscript>8</Superscript>Be reaction

A transfer-reaction experiment of ⁹Be(⁹Be, ¹⁰Be)⁸Be was performed at a beam energy of 45 MeV. Excited states in ¹⁰Be up to 18.80 MeV are produced using missing mass and invariant mass methods. Most of the observed high-lying resonant states, reconstructed from the α + ⁶He and t + ⁷Li decay channels, agree with the previously reported results. In addition, two new resonances at 15.6 and 18.8 MeV are identified from the present measurement. The 18.55 MeV state is found to decay into both the t + ⁷Li_g.s. and t + ⁷Li* (0.478 MeV) channels, with a relative branching ratio of 0.93 ± 0.33. Further theoretical investigations are encouraged to interpret this new information on cluster structure in neutron-rich light nuclei.     

Determination of the cluster spectroscopic factor of the 10.3 MeV state in 12Be

From an inelastic excitation and breakup experiment with a ¹²Be beam at 29 MeV/u, a large ⁴He+⁸He cluster decay width of 1.1(2) MeV is determined for a state at an excitation energy of 10.3 MeV and with a spin parity of 0+. By using the R-matrix analysis, a cluster spectroscopic factor of 0.53(10) is extracted from the cluster partial width, providing a strong support for the clustering structure in ¹²Be. A specially designed zero-degree telescope played an essential role in the present experiment and has been demonstrated to be a promising tool in future studies of the molecular-like resonances near the cluster separation threshold.     

Preparation and pervaporation performance of high-quality silicalite-1 membranes

High-performance silicalite-1 membranes were successfully synthesized on novel porous silica tubes by two-step in-situ hydrothermal synthesis.The flux and separation factor towards ethanol/water mix- ture at 60℃were 0.56 kg/(m2·h)and 84,respectively.The as-synthesized silicalite-1 membranes were characterized by scanning electron microscopy(SEM).The influence of different synthesis conditions on the separation performance of the silicalite-1 membranes was investigated.It was found that the average flux of silicalite-1 membranes was improved by about 26?ter filling the silica tubes with mixed solution containing glycerol and water.After calcinating at 400℃for 5 h repeatedly,membrane synthesized on silica tube still showed high pervaporation performance towards ethanol/water mixture even at a calcination rate of 4℃/min,which suggested that silica support was more suitable for pre- paring high-performance silicalite-1 membranes.     

Theoretical studies of the transport property of oligosilane

The transport mechanisms of four σ-conjugated systems were comparatively studied by combining ATK and Gaussian 03 calculations. It was found that the charge-doped oligosilane behaved in a different way from the boron doped and phosphorus doped oligosilanes in terms of the transmission property. The charge-doped oligosilane showed almost no conductivity owing to the damage of the electron transfer path by charge-doping. By contrast, the boron doped and phosphorus doped oligosilanes were demonstrated to be good semiconductors and NDR behavior was observed for them. This is a reasonable result after the analysis of the transmission spectra, MPSH states, energy gap, conjugation effect, and scattering effect.     

Synthesis and separation performance of silicalite-1 membranes on silica tubes

High-performance silicalite-1 membranes were synthesized on silica tubes by in-situ hydrothermal synthesis. By using the "solution-filling (SF)" method, the average flux of membranes with the SF method was improved by about 25% compared to that of the membranes without using the SF method; the flux and the separation factor of the membranes prepared with the SF method for an ethanol/water mixture at 60 ℃ were 0.99 kg/(m2·h) and 73, respectively. It was found that the membranes synthesized on silica tubes ex...     

Stable ZnO/ionic liquid hybrid materials: novel dual-responsive superhydrophobic layers to light and anions

Novel dual-responsive superhydrophobic hybrid materials,ZnO/SAMs(self-assembled monolayers)of ionic liquids(ILs)with different counter-anions(I-,BF4-,PF6-and Tf2N-),were synthesized and characterized.ZnO nanoparticles were first deposited on glass surfaces to produce roughness.Next,SAMs of fluorinated-alkyl-3-(3-triethoxysilylpropyl)-4,5-dihydro-imidazoliumiodide(abb.[C8Ftespim]I)were grafted onto these surfaces via-Si-O-covalent bonds using self-assembly technique.The Iion could be subsequently exchanged with BF4-,PF6-or Tf2N-through a simple aqueous anion-exchange reaction.The ZnO/ILs hybrid layers were characterized by atomic-force microscopy(AFM),scanning-electron microscopy(SEM)and X-ray photoelectron spectroscopy(XPS).Their wettability was estimated through the measurements of static and dynamic contact angles(CAs).Compared to corresponding films of ZnO/[C8Ftespim]I with CAs 140.7°±2.0°,films of ZnO/[C8Ftespim]PF6 and ZnO/[C8Ftespim]Tf2N showed CAs with 154.0°±2.0°and 152.0°±2.0°,respectively that remained for a long time.This result suggests that anion-exchange can afford superhydrophobic materials.In addition,the wettability of ZnO/[C8Ftespim]X hybrid layers can be reversibly switched by altering ultraviolet(UV)irradiation and dark storage,which shows a photo-induced reversible switch of wettability.The synergistic action of ZnO nanoparticles and SAMs of ILs produced light-anion dual-responsive superhydrophobic materials with ideal stability.     

自组装方法与三维光子晶体制作

光子晶体,特别是三维光子晶体,可能成为信息处理和通信等领域的新型功能材料.光子晶体的制作方法可分为"自上而下"的物理方法和"自下而上"的化学自组装方法.化学自组装方法是制作三维光子晶体最为经济有效的方法.本文在阐述自组装方法的种类、一般过程、优点和不足等内容的基础上,分别分析和总结了带有各种功能缺陷的三维光子晶体的制作,这些缺陷主要包括线缺陷、面缺陷和点缺陷.从研究中可以看出,化学自组装方法通常需要结合其他方法才能实现缺陷的嵌入.近些年,三维光子晶体制作在材料选取、结构设计和方法改进等方面都有一些最新进展,本文对此进行了较为详尽的评述,并对我们课题组的研究进行了总结.最后对光子晶体的研究和制作方向进行了展望.