共查询到20条相似文献,搜索用时 765 毫秒
1.
Direct electrochemistry behavior of Cytochrome c on silicon dioxide nanoparticles-modified electrode
A newfangled direct electrochemistry behavior of Cytochrome c (Cyt c) was found on glassy carbon (GC) electrode modified with the silicon dioxide (SiO2) nanoparticles by physical adsorption. A pair of stable and well-defined redox peaks of Cyt c′ quasi-reversible electrochemical reaction were obtained with a heterogeneous electron transfer rate constant of 1.66×10-3 cm/s and a formal potential of 0.069 V (vs. Ag/AgCl) (0.263 V versus NHE) in 0.1 mol/L pH 6.8 PBS. Both the size and the amount of SiO2 nanoparticles could influence the electron transfer between Cyt c and the electrode. Electrostatic interaction which is between the negative nanoparticle surface and positively charged amino acid residues on the Cyt c surface is of importance for the stability and reproducibility toward the direct electron transfer of Cyt c. It is suggested that the modification of SiO2 nanoparticles proposes a novel approach to realize the direct electrochemistry of proteins. 相似文献
2.
Intelligent polymers or stimuli-responsive polymers may exhibit distinct transitions in physical-chemical properties, including conformation, polarity, phase structure and chemical composition in response to changes in environmental stimuli. Due to their unique 'intelligent' characteristics, stimuli-sensitive polymers have found a wide variety of applications in biomedical and nanotechnological fields. This review focuses on the recent developments in biomedical application of intelligent polymer systems, s... 相似文献
3.
Small crystal zeolites ZSM-5 with sizes of 150–300 nm were synthesized using the colloidal silicate precursors as the silica
source created by the acid-catalyzed hydrolysis of tetraethylorthosilicate with tetrapropylammonium bromide as the structure-directing
agent within a short crystallization time of 20–35 h. The precursors and final products were detected by XRD, SEM, ICP and
DLS.
Supported by the National Natural Science Foundation of China (Grant No. 20776069), Key Natural Science Foundation for Universities
of Jiangsu Province (Grant No. 06KJA53012), and Program for Changjiang Scholars and Innovative Research Team in University
(Grant No. PCSIRT 0732) 相似文献
4.
Based on the mechanism of H2O2-mediated hydrolysis of sulfonates, two fluorescein disulfonates compounds (FS-1 and FS-2) were designed and synthesized as
the highly selective and sensitive fluorescent probes for imaging H2O2 in living cells. The probes were detected with elemental analysis, IR, 1H NMR and 13C NMR. Upon reaction with H2O2, the probes exhibit strong fluorescence responses and high selectivity for H2O2 over other reactive oxygen species and some biological compounds. Furthermore, the sulfonate-based probes, as novel fluorescent
reagents, are cell-permeable and can detect micromolar changes in H2O2 concentrations in living cells by using confocal microscopy.
Supported by the National Basic Research Program of China (Grant No. 2007CB936000), the National Natural Science Funds for
Distinguished Young Scholar (Grant No. 20725518), Major Program of the National Natural Science Foundation of China (Grant
No. 90713019), the National Natural Science Foundation of China (Grant No. 20875057), the Natural Science Foundation of Shandong
Province, China (Grant No. Y2007B02), and the Science and Technology Development Programs of Shandong Province, China (Grant
No. 2008GG30003012) 相似文献
5.
XuShu Yang XiaoDong Wang Si Luo Li Ji Liang Qin Rong Li Cheng Sun LianSheng Wang 《中国科学B辑(英文版)》2009,52(7):1042-1050
Close attention has been paid to estrogen compounds because these chemicals may pose a serious threat to the health of humans and wildlife. Estrogen receptor (ER) exists as two subtypes, ERα and ERβ. The difference in amino acids sequence of the binding sites of ERα and ERβ might lead to a result that some synthetic estrogens and naturally occurring steroidal ligands have different relative affinities and binding modes for ERα and ERβ. In this investigation, comparative molecular similarity indices analysis... 相似文献
6.
ZHU HaoMiao LI Bo LI Li SHEN Jian Jiangsu Engineering Research Center for Bio-medical Function Materials Nanjing Normal University Nanjing China Jiangsu Research Center of Surface Interface Chemical Engineering Technology Nanjing University Nanjing China 《中国科学B辑(英文版)》2008,51(1):78-85
Molecular dynamics simulations are applied to the initial stage of polyalanine13 conformational transi- tion from α-helix to random coil in aqueous environment and the interaction of polyalanine13 with zwitterionic and hydrophobic surfaces respectively in the same condition. The analysis of secondary structure, hydrogen bonds, RMSD, dihedral distribution, and the degree of adsorption are performed. The results show that zwitterionic structure maintains the natural behavior of polyalanine13 in water to a better extent, which should be an indirect proof of the hypothesis of "maintain of normal structure." 相似文献
7.
Yttria-stabilized zirconia (YSZ) micro tubular electrolyte membranes for solid oxide fuel cells (SOFCs) were prepared via the combined wet phase inversion and sintering technique. The as-derived YSZ mi- cro tubes consist of a thin dense skin layer and a thick porous layer that can serve as the electrode of fuel cells. The dense and the porous electrolyte layers have the thickness of 3-5 μm and 70-90 μm, respectively, while the inner surface porosity of the porous layer is higher than 28.1%. The two layers are perfectly integrated together to preclude the crack or flake of electrolyte film from the electrode. The presented method possesses distinct advantages such as technological simplicity, low cost and high reliability, and thus provides a new route for the preparation of micro tubular SOFCs. 相似文献
8.
9.
Azo-salicylaldehyde Schiff base-typed receptors containing an acidic H-bond donor moiety were syn-thesized and characterized. The UV-Vis data indicate that these receptors could act as selective col-orimetric sensors for basic anions and acidic species hydrogen sulfate by different color changes in a water-containing medium. The experiment of Brφnsted acid-base reaction by adding the sodium hy-droxide or perchloric acid revealed that the mechanism of recognition of anions might be deprotona-tion/protonation of the OH fragments by interacting with different anions and that the deprotona-tion/protonation process is fully reversible. The deprotonation/protonation of the receptors is respon-sible for the dramatic color change. 相似文献
10.
Monolithic materials were prepared in capillaries by in situ polymerization of acrylamide, glycidyl methacrylate and N,N′-memylenebisacrylamid in the presence of trinary porogens, including 1,4-butanediol, dodecanol and dimethyl sulphoxide. With Ampholine immobilized on the monolith by chemical bonding according to their pIs, the monolithic immobilized pH gradient (M-IPG) was prepared, and applied to the separation of four standard proteins. Compared with polyacrylate based M-IPG, the hydrophilicity of the new material was improved. It could not only avoid the adsorption of proteins, but also make the synthesized procedure simple, which showed great potential in the analysis of proteins. 相似文献
11.
A novel family of diarylethene (DTE)-phthalocyanine (Pc) dyad systems were designed and synthesized. It was found that the significant change in the extension of the linear π-conjugation of DTE when irradiated by 254 nm UV light directly made the absorption of the Q-band of phthalocyanine decrease. Detecting the absorption changes of the Q-band would not induce the reversible photochromic reaction. Therefore, non-destructive readout was feasible based on the spectral changes of the Q-band when such materials were used as storage media. 相似文献
12.
LiXi Zeng YuJian He ZhiFeng Dai Jian Wang CaiQi Wang YongGang Yang 《中国科学B辑(英文版)》2009,52(8):1227-1234
Supramolecular chirality and molecular self-assembly are important and interesting phenomena in living and non-living systems.In this work,supramolecular chirality of achiral pseudoisocyanine(PIC) J-aggregates was successfully induced by D-,L-phenylalanine(Phe) and other amino acids in NaCl solution.The chiral J-aggregates showed a characteristic,induced circular dichroism(ICD) in the visible region of J-band chromophore which depends on the absolute configuration,concentration and side groups of α-amino ac... 相似文献
13.
Polybrominated diphenyl ether (PBDE) is a persistently environmental pollutant ubiquitously found in wildlife and humans. Although concern on PBDE’s toxic effects is steadily increasing, its action on the central nervous system (CNS) remains largely unknown. To address this issue, the present study ex- amined the development inhibition of PBDE in neurons. The primary cultured hippocampal neurons of rat were exposed to the commercial decabromodiphenyl ether (deca-BDE), and the neurite length, bi- furcation, and synapse formation and maturation were evaluated, based on the confocal microscope imaging. The results showed that the development inhibition in neurons occurred at 15 μmol/L, indi- cating that PBDE is a potent neurotoxicant and it might obviously inhibit the development of cultured neurons. 相似文献
14.
Huang Tang WangLiang Li QingFen Liu LiLi Guan JiaQing Song JianMin Xing HuiZhou Liu 《中国科学B辑(英文版)》2009,52(3):276-281
Mesoporous aluminosilicates (MAS) bearing microporous zeolite units and mesoporous structures were synthesized by the hydrothermal
method. Adsorptive desulfurization ability of model oil and hydrotreated diesel was studied. The effects of template concentration,
crystalization time and calcination time were investigated. The desulfurization ability of adsorbents was improved by transitional
metal ion-exchanging. The adsorptive desulfurization of diesel was carried out on a fixed-bed system. The results show that
the adsorptive capacity is MAS>MCM-41>NaY. The improvement of desulfurization ability of MAS by Cu+ is more significant than that of Ag+.
Supported by National Basic Research Program of China (Grant No. 2006CB202507), National High-tech R&D Program (Grant No.
2006AA02Z209), and the National Natural Science Foundation of China (Grant No. 20806086) 相似文献
15.
A novel hydrophilic copolymer P(NI-HEMA) containing the pendant group of naphthalimide moiety has been prepared. In the aqueous
buffer solution, its film on the glass substrate shows an obvious fluorescence change and excellent linear relevance in the
pH range of 5.8–8.0. Specifically, using the isobestic point at 406 nm as excitation wavelength can avoid the UV irradiation
and the tedious calibration process. The film stability and hydrophilicity of copolymer P(NI-HEMA) were studied. Because of
the easy synthesis, low price and high linear relevance to pH, the hydrophilic chemosensor film of P(NI-HEMA) could be potentially
applied as a low-cost pH indicator for high-throughput bioprocessing in microreactors.
Supported by the National Natural Science Foundation of China (Grant No. 20672036), Program for Shanghai Shuguang Project
(Grant No. 07SG34), and New Century Excellent Talents in University (Grant No. NCET-06-0418) 相似文献
16.
A series of tetracene-doped anthracene crystals with different doping concentrations (the highest molar ratio 100 1) are grown
from solution. Crystal structures and optical characteristics of the above mixed crystals are investigated at room temperature.
By changing the doping concentrations, the fluorescence can be adjusted from blue-green to green and even to yellow-green.
The emission spectra of anthracene/tetracene (An/Te) mixed crystals reveal the sensitized fluorescence of tetracene and the
partial quenching of anthracene emission. The data of transient photoluminescence (PL) decays illustrate that in An/Te mixed
crystals, the decay of anthracene becomes faster, while the PL lifetime of tetracene is longer than that of the tetracene
single crystals. All above experimental results suggest that there is excitation energy transfer from anthracene to tetracene
in the mixed crystals.
Supported by the National Natural Science Foundation of China (Grant No. 5057 3039) and the National Key Basic Research and
Development Program of China (Grant No. 2006CB806200) 相似文献
17.
H2 with low CO concentration is produced via photocatalytic reforming of glucose (as a representative of biomass component)
on metal/TiO2 catalyst (metals: Pt, Rh, Ru, Ir, Au, Ni, Cu). It is shown that the loaded metals generally enhance the rate of H2 production, while they depress the CO selectivity. Both H2 production and CO selectivity are strongly dependent on the kind of deposited metals on TiO2. For example, Rh/TiO2 catalyst is found to be most active for H2 production while with the most extremely low CO concentration from the photocatalytic reforming of glucose.
Supported by the National Natural Science Foundation of China (Grant No. 20403018, 20503034), National Basic Research Program
of China (Grant No. 2003CB214504), and Knowledge Innovation Program of the Chinese Academy of Sciences (DICP K2006E2) 相似文献
18.
MEIER Herbert 《中国科学B辑(英文版)》2009,52(7):1051-1056
A rapid and efficient synthesis of novel dendrimer homotriptycenes is presented. The dendronized 9,10-dihydroanthracen-9-ols 4, having high electron densities in the benzene rings of the Fréchet-type dendrons, exhibited in the presence of acid a quantitative transannular ring closure to the corresponding dendritic homotriptycenes. The electron-donating Fréchet-type dendrons enabled the intramolecular FC alkylation by a regioselective 1,7-elimination of H2O. 相似文献
19.
LingShu Wan BeiBei Ke XiaoKai Li XiangLin Meng LuYao Zhang ZhiKang Xu 《中国科学B辑(英文版)》2009,52(7):969-974
Highly ordered honeycomb-patterned polystyrene (PS)/poly(ethylene glycol) (PEG) films were prepared by a water-assisted method
using an improved setup, which facilitated the formation of films with higher regularity, better reproducibility, and larger
area of honeycomb structures. Surface aggregation of hydrophilic PEG and adsorption of bovine serum albumin (BSA) on the honeycomb-patterned
films were investigated. Field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) were used to
observe the surface morphologies of the films before and after being rinsed with water. As confirmed by the FESEM images and
the AFM phase images, PEG was enriched in the pores and could be gradually removed by water. The adsorption of fluorescence-labeled
BSA on the films was studied in visual form using laser scanning confocal microscopy. Results clearly demonstrated that the
protein-resistant PEG was selectively enriched in the pores. This water-assisted method may be a latent tool to prepare honeycomb-patterned
biofunctional surfaces.
Supported by the National Natural Science Foundation of China (Grant No. 50803053), the National Natural Science Foundation
of China for Distinguished Young Scholars (Grant No. 50625309), the National Postdoctoral Science Foundation of China (Grant
Nos. 20070421172 & 20081466) and the National Undergraduate Innovative Test Program 相似文献
20.
Unprecedented synthesis of chiral (aza)crown ethers of calix[4]arene derivatives bearing a carboxyl amide bridge was described. The synthesis proceeds through condensation of the corresponding dinitriles with optically active 1,2-aminoalcohols,and is catalyzed by the ZnCl2 Lewis acid at elevated temperature in a very efficient one-pot process. The cavity of calix[4](aza)crowns can encapsulate methanol molecules by O—H...π interaction,which has been confirmed by X-ray crystal structures and ESI-MS. 相似文献