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991.
Hong Chen Wei Song Feng Zhou Zhongkui Wu He Huang Junhu Zhang Quan Lin Bai Yang 《Colloids and surfaces. B, Biointerfaces》2009,71(2):275-281
Chemical homogeneous poly(dimethylsiloxane) (PDMS) surface with dot-like protrusion pattern was used to investigate the individual effect of surface microtopography on protein adsorption and subsequent biological responses. Fibrinogen (Fg) and fibronectin (Fn) were chosen as model proteins due to their effect on platelet and cell adhesion, respectively. Fg labeled with 125I and fluorescein isothiocyanate (FITC) was used to study its adsorption on flat and patterned surfaces. Patterned surface has a 46% increase in the adsorption of Fg when compared with flat surface. However, the surface area of the patterned surface was only 8% larger than that of the flat surface. Therefore, the increase in the surface area was not the only factor responsible for the increase in protein adsorption. Clear fluorescent pattern was visualized on patterned surface, indicating that adsorbed Fg regularly distributed and adsorbed most on the flanks and valleys of the protrusions. Such distribution and local enrichment of Fg presumably caused the specific location of platelets adhered from platelet-rich plasma (PRP) and flowing whole blood (FWB) on patterned surface. Furthermore, the different combination of surface topography and pre-adsorbed Fn could influence the adhesion of L929 cells. The flat surface with pre-adsorbed Fn was the optimum substrate while the virgin patterned surface was the poor substrate in terms of L929 cells spread. 相似文献
992.
Chengbin Jing Haiyang Shan Chuanjian Zhang Xiaodan Zang Wei Bai Junhao Chu 《Journal of Sol-Gel Science and Technology》2009,51(2):139-145
The solids content and gelation time of aqueous germanate solution were examined in this work. Samples of 5, 10 and 20 mol%
Mn doped Ge were prepared by using the aqueous germanate solution as a liquid Ge precursor. No second phase such as Mn5Ge3 was detected in the 5 and 10 mol% Mn doped samples, implying that Mn ions were uniformly diluted into the Ge host matrix.
The 5 and 10 mol% Mn-doped Ge samples exhibit room-temperature ferromagnetic behaviors that are likely originated from the
RKKY (Ruderman–Kittel–Kasuya–Yosida)-like interaction between the localized Mn ions in the Ge matrix. Therefore, the aqueous
germanate solution can be an alternative sol–gel precursor for preparation of the Mn
x
Ge1−x
diluted magnetic semiconductors (DMSs). 相似文献
993.
A technique for production of nanocrystalline cellulose with a narrow size distribution 总被引:3,自引:0,他引:3
Nanocrystalline cellulose (NCC) was prepared by sulfuric acid hydrolysis of microcrystalline cellulose. A differential centrifugation
technique was studied to obtain NCC whiskers with a narrow size distribution. It was shown that the volume of NCC in different
fractions had an inverse relationship with relative centrifugal force (RCF). The length of NCC whiskers was also fractionized
by differential RCF. The aspect ratio of NCC in different fractions had a relatively narrow range. This technique provides
an easy way of producing NCC whiskers with a narrow size distribution. 相似文献
994.
Lingyun Chen Hang Xing Junfeng Bai Guoqing Jiang 《Journal of solid state chemistry》2009,182(6):1387-314
Novel MnO nano- and microparticles including spherical nanoparticles and various micropolyhedra of pyramid-like, truncated rectangular pyramid-like, cubic, and rhombic dodecahedral particles, were controllably synthesized via solid-state thermolysis of inorganic core containing molecular clusters [Mn12O12(O2CR)16(H2O)4] (R=C6H5, CH3, and C6H5OCH2) in a conventional horizontal tube furnace. Among them, pyramid-like, truncated rectangular pyramid-like, cubic, and rhombic dodecahedral MnO submicroscale particles were reported for the first time. The products were characterized by XRD, XPS, Raman spectrum, SEM, EDX, TEM and HRTEM. During the reaction process, thermolysis temperature, reaction time, and different molecular clusters {Mn12} precursors with different organic ligands as well play important roles in determining the sizes and shapes of the final products. The formed MnO nanospheres from [Mn12O12(O2CC6H5)16(H2O)4] at 400 °C for 10 h exhibited weak ferromagnetic behavior at low temperature which may be due to the size-effect of nanomaterials. Furthermore, the possible formation mechanism was also discussed. 相似文献
995.
Lihua Bai Jianxia Guo Franklin A. Bontempo III Julie L. Eiseman 《Photochemistry and photobiology》2009,85(4):1011-1019
The ability to noninvasively measure photosensitizer concentration at target tissues will allow optimization of photodynamic therapy (PDT) and could improve outcome. In this study, we evaluated whether preirradiation tumor phthalocyanine 4 (Pc 4) concentrations, measured noninvasively by the optical pharmacokinetic system (OPS), correlated with tumor response to PDT. Mice bearing human breast cancer xenografts were treated with 2 mg kg−1 Pc 4 iv only, laser irradiation (150 J cm−2 ) only, Pc 4 followed by fractionated irradiation or Pc 4 followed by continuous irradiation. Laser irradiation treatment was initiated when the tumor to skin ratio of Pc 4 concentration reached a maximum of 2.1 at 48 h after administration. Pc 4 concentrations in tumor, as well as in Intralipid in vitro , decreased monoexponentially with laser fluence. Pc 4-PDT resulted in significant tumor regression, and tumor response was similar in the groups receiving either fractionated or continuous irradiation treatment after Pc 4. Tumor growth delay following Pc 4-PDT correlated with OPS-measured tumor Pc 4 concentrations at 24 h prior to PDT ( R 2 = 0.86). In excised tumors, OPS-measured Pc 4 concentrations were similar to the HPLC-measured concentrations. Thus, OPS measurements of photosensitizer concentrations can be used to assist in the scheduling of Pc 4-PDT. 相似文献
996.
997.
Yan-Chun Bai 《Journal of solid state chemistry》2009,182(1):89-4034
Three new polyoxometalates X7[PMo8O30] (X=Na+, 1; K+, 2; NH4+, 3) have been synthesized with the classical Keggin and/or Dawson heteropolymolybdophosphates and PCl5 in acetonitrile-water solutions via hydrothermal treatment. The three compounds were characterized by different analyses including IR, 31P NMR spectroscopy, elemental analysis, electrochemistry, thermogravimetric analysis (TGA) and powder X-ray diffraction (XRD). Single crystal X-ray analyses were carried out on Na7[PMo8O30] (1) and (NH4)7[PMo8O30] (3). Compound 1 and 3 crystallize in the orthorhombic system. The structure of compound 2 was confirmed by the IR spectra and powder XRD. All the three compounds contain the same octamolybdophosphate polyoxoanion [PMo8O30]7−, which consists of two Mo4O15 moieties linked by one central PO4 tetrahedron, leading to a remarkable sandglass-like structure. 相似文献
998.
聚酰亚胺研究新进展 总被引:5,自引:0,他引:5
汪称意|李光|江建明|杨胜林|金俊弘 《化学进展》2009,21(1):174-181
聚酰亚胺(PI)是一类重要的高性能聚合物,广泛应用在航空航天、微电子、汽车、石油等高科技领域。由于其结构上的可设计性,世界上越来越多的研究者投入到这类高技术材料的研究开发中。本文分别从可溶性PI的分子设计与合成、功能性PI的合成与用途、PI绿色合成方法、PI纳米复合材料的制备4个方面综述了近年来PI的研究热点和新进展,为了解聚酰亚胺的研究提供了有价值的信息。 相似文献
999.
Ying Wang Wenzhao Jia Timothy Strout Ashely Schempf Heng Zhang Baikun Li Junhong Cui Yu Lei 《Electroanalysis》2009,21(12):1432-1438
Highly porous polypyrrole (PPy)‐coated TiO2/ZnO nanofibrous mat has been successfully synthesized. The core TiO2/ZnO nanofibers have an average diameter of ca. 100 nm and the shell of ultrathin PPy layer has a thickness of ca. 7 nm. The NH3 gas sensor using the as‐prepared material exhibited a fast response over a wide dynamic range and high sensitivity with a detection limit of 60 ppb (S/N=3). Compared to conventional pristine PPy film, the improved performance in NH3 detection can be attributed to the free access of NH3 to PPy and a minimized gas diffusion resistance through the ultrathin PPy layer. 相似文献
1000.
David M. Good Craig D. Wenger Graeme C. McAlister Dina L. Bai Donald F. Hunt Joshua J. Coon 《Journal of the American Society for Mass Spectrometry》2009,20(8):1435-1440
Tandem mass spectra (MS/MS) produced using electron transfer dissociation (ETD) differ from those derived from collision-activated
dissociation (CAD) in several important ways. Foremost, the predominant fragment ion series are different: c- and z
·-type ions are favored in ETD spectra while b- and y-type ions comprise the bulk of the fragments in CAD spectra. Additionally, ETD spectra possess charge-reduced precursors
and unique neutral losses. Most database search algorithms were designed to analyze CAD spectra, and have only recently been
adapted to accommodate c- and z
·-type ions; therefore, inclusion of these additional spectral features can hinder identification, leading to lower confidence
scores and decreased sensitivity. Because of this, it is important to pre-process spectral data before submission to a database
search to remove those features that cause complications. Here, we demonstrate the effects of removing these features on the
number of unique peptide identifications at a 1% false discovery rate (FDR) using the open mass spectrometry search algorithm
(OMSSA). When analyzing two biologic replicates of a yeast protein extract in three total analyses, the number of unique identifications
with a ∼1% FDR increased from 4611 to 5931 upon spectral pre-processing—an increase of ∼28. 6%. We outline the most effective
pre-processing methods, and provide free software containing these algorithms. 相似文献