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1.
CdTe nanocrystals (CdTe NCs) were achieved by reaction of CdCl2 with KHTe solution and were capped with sodium mercaptoacetate. The product was detected by transmission electron microscopy
(TEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive spectroscopy (EDS), fluorescence spectra,
ultraviolet-visible spectra and X-ray diffraction (XRD). The CdTe NCs are of cubic structure and the average size is about
5 nm. The fluorescence quantum yield of CdTe NCs aqueous solution increased from 37% to 97% after 20 d under room light. The
maximum λ
em of fluorescence changed from 543 nm to 510 nm and the blue shift was 33 nm. CdTe NCs aqueous solution can be steady for at
least 10 months at 4 in° a refrigerator. The resonance Rayleigh scattering (RRS) of CdTe NCs in the aqueous solution was investigated.
The maximum scattering peak was located at about 554 nm. The interactions of CdTe NCs with amikacin sulfate (AS) and micronomicin
sulfate (MS) were investigated respectively. The effects of AS and MS on fluorescence and RRS of CdTe NCs were analyzed. It
was found that AS and MS quenched the photoluminescence of CdTe NCs and enhanced RRS of CdTe NCs. Under optimum conditions,
there are linear relationships between quenching intensity (F
0-F), intensity of RRS (I-I
0) and concentration of AS and MS. The detection limits (3б) of AS and MS are respectively 3.4 ng·mL−1 and 2.6 ng·mL−1 by the fluorescence quenching method, and 15.2 ng·mL−1 and 14.0 ng·mL−1 by the RRS method. The methods have high sensitivity, thus CdTe NCs may be used as fluorescence probes and RRS probes for
the detection of aminoglycoside antibiotics.
Supported by the National Natural Science Foundation of China (Grant No. 20475045) 相似文献
2.
Yuan Ruo Cao ShuRui Chai YaQin Gao FengXian Zhao Qing Tang MingYu Tong ZhongQiang Xie Yi 《中国科学B辑(英文版)》2007,50(5):620-628
Alternate adsorption of positively charged colloid-Au nanoparticles (nano-Au⊕) and negatively charged hemoglobin (Hb) on L-cysteine (L-cys) modified gold electrode resulted in the assembly of {Hb/nano-Au⊕}n layer-by-layer films/L-cys modified gold electrode. The nano-Au⊕ was characterized by transmission electron micrograph (TEM) and microelectrophoresis. The modified electrode interface morphology was characterized by electrochemical impedance spectroscopy (EIS), atomic force mi- croscopy (AFM), cyclic voltammograms (CV) and chronoamperometry. Direct electron transfer between hemoglobin and gold electrodes was studied, and the apparent Michaelis-Menten constant ( km app) of the modified electrode was evaluated to be 0.10 mmol·L?1. Moreover, the higher activity of proteins in the nano-Au⊕ films could be retained compared with the electropolymerization membrane, since the pro- teins in nano-Au⊕ films retained their near-native structure. Direct electron transfer between hemoglo- bin and electrode and electrochemically catalyzed reduction of hydrogen peroxide on a modified elec- trode was studied, and the linear range was from 2.1×10-8 to 1.2 ×10?3 mol·L-1 (r = 0.994) with a detection limit of 1.1×10-8 mol·L-1 H2O2. 相似文献
3.
JingQiang Cui JiangLi Fan XiaoJun Peng ShiGuo Sun GuiCai Chen KeXin Guo 《中国科学B辑(英文版)》2009,52(6):780-785
A new fluorescent sensor (1) for Pb2+ containing a 1,4-dicyano-2,5-bis(styryl)benzene fluorophore and 2-(N,N′-bis(carboxylmethyl))amino-1-carboxylmethoxylbenzene as receptor has been synthesized. The sensor selectively responds to
Pb2+ in the aqueous environment, and brings about similar and significant changes in one- and two-photon excited emission spectra:
λ
max red-shift from 460 (519) to 590 nm. The selective response is pH-independent in a large physiological pH range, and two-photon
action cross section (ϕδ) is 51 GM (1 GM = 1×10−50 cm4·s·photon−1·molecule−1) at 740 nm.
Supported by the National Natural Science Foundation of China (Grant Nos. 20705621 & 20706008), the National Basic Research
Project of China (Grant No. 2009CB724706), the Ministry of Education of China, Changjiang Scholars Innovative Research Team
in University (Grant No. IRT0711) and Cultivation Fund of the Key Scientific and Technical Innovation Project (Grant No. 707016) 相似文献
4.
Nanogold particles of 10 nm were used to label goat anti-human IgG (GIgG) to obtain nanogold-labeled GIgG (AuGIgG). In a citrate-HCI
buffer solution of pH 2.27, AuGIgG showed a strong catalytic effect on the reaction between HAuCl4 and NH2OH to form big gold particles that exhibited a resonance scattering (RS) peak at 796 nm. Under the chosen conditions, AuGIgG
combined with IgG to form immunocomplex AuGIgG-IgG that can be removed by centrifuging at 16000 r/min. AuGIgG in the centrifuging
solution also showed catalytic effect on the reaction. On those grounds, an immunonanogold catalytic RS assay for IgG was
designed. With addition of IgG, the amount of AuGIgG in the centrifuging solution decreased; the RS intensity at 796 nm (I
796 nm) decreased linearly. The decreased intensity ΔI
796 nm was linear with respect to the IgG concentration in the range of 0.08–16.0 ng · mL−1 with a detection limit of 0.02 ng · mL−1. This assay was applied to analysis of IgG in sera with satisfactory sensitivity, selectivity and rapidity.
Supported by the National Natural Science Foundation of China (Grant No. 20667001), Natural Science Foundation of Guangxi
Province (Grant No. 0728213), and the Foundation of New Century Ten-Hundred-Thousand Talents of Guangxi Province 相似文献
5.
N,N-dimethyl-3-oxa-glutaramic acid was purified and characterized by 1H-NMR, Fourier transform infrared spectroscopy (FT-IR) and elemental analysis. The thermal decomposition of the title compound
was studied by means of thermogravimetry differential thermogravimetry (TG-DTG) and FT-IR. The kinetic parameters of its second-stage
decomposition reaction were calculated and the decomposition mechanism was discussed. The kinetic model function in a differential
form, apparent activation energy and pre-exponential constant of the reaction are 3/2 [(1−α)1/3−1]−1, 203.75 kJ·mol−1 and 1017.95s−1, respectively. The values of ΔS
≠, ΔH
≠ and ΔG
≠ of the reaction are 94.28 J·mol−1·K−1, 203.75 kJ·mol−1 and 155.75 kJ·mol−1, respectively.
Supported by the National Natural Science Foundation of China (Grant No. 20106009) 相似文献
6.
Planar or quasi-planar octa- and ennea-coordinate aluminum and gallium in boron rings 总被引:2,自引:1,他引:1
GUO JinChang YAO WenZhi LI Zhuo LI SiDian Institute of Materials Science Department of Chemistry Xinzhou Teachers’ University Xinzhou China International School of Software Wuhan University Wuhan 《中国科学B辑(英文版)》2009,52(5):566-570
An ab initio theoretical investigation has been performed on planar or quasi-planar octa-and ennea-coordinate Al and Ga centered in X@B8- and X@B9 (X=Al, Ga). These high symmetry molecular wheels all turned out to be true minima of the systems and σ+π double aromatic in nature, similar to the previously characterized D8h B@B8- both electronically and geometrically. Adiabatic and vertical detachment energies of the anions and the ionization potentials of the neutrals have been calculated to aid their eventua... 相似文献
7.
A single anthryl appended meso-tetraphenylporphyrin (TPP) dyad has been synthesized and applied in fluorescence sensing of
iodine based on the intramolecular excitation energy transfer. The molecular recognition of the sensor is based on the interaction
of iodine with inner anthracene moiety of the dyad, while the signal reporter for the recognition process is the TPP fluorescence
quenching. Because the emission spectrum of anthracene is largely overlapped with the Soret band absorption of TPP, intramolecular
excitation energy transfer interaction occurs between the donor, anthracene and acceptor, TPP. This energy transfer leads
to TPP fluorescence emission by excitation of anthracene. The sensor was constructed by immobilizing the dyad in a plasticized
poly(vinyl chloride) (PVC) membrane. The sensing membrane shows higher sensitivity compared to the sensors by using anthracene,
TPP, or a mixture of anthracene and TPP as sensing materials. Under the optimum conditions, iodine in a sample solution can
be determined from 2.04 to 23.6 mmol·L−1 with a detection limit of 33 nmol·L−1. The sensing membrane shows satisfactory response characteristics including good reproducibility, reversibility and stability,
as well as the short response time of less than 60 s. Except for Cr2O72− and MnO4−, other common metal ions and anions in foodstuff do not interfere with iodine determination. The proposed method was applied
in the determination of iodine in table salt samples. The results agree well with those obtained by other methods.
Supported by the National Outstanding Youth Science Foundation of China (Grant No. 20525518), the National Natural Science
Foundation of China (Grant No. 20775005), and the National Natural Science Foundation of Hunan province (Grant No. JJ076021) 相似文献
8.
Gold nanoparticles (nano Au)/titanium dioxide (TiO2) hollow microsphere membranes were prepared on the carbon paste electrode (CPE) for enhancing the sensitivity of DNA hybridization
detection. The immobilization of nano Au and TiO2 microsphere was investigated with cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The hybridization
events were monitored with EIS using [Fe(CN)6]3−/4− as indicator. The sequence-specific DNA of the 35S promoter from cauliflower mosaic virus (CaMV35S) gene was detected with
this DNA electrochemical sensor. The dynamic detection range was from 1.0×10−12 to 1.0×10−8 mol/L DNA and a detection limit of 2.3×10−13 mol/L could be obtained. The polymerase chain reaction (PCR) amplification of the terminator of nopaline synthase (NOS) gene
from the real sample of a kind of transgenic soybean was also satisfactorily detected.
Supported by the National Natural Science Foundation of China (Grant Nos. 20635020 and 20375020), Doctoral Foundation of the
Ministry of Education of China (Grant No. 20060426001) and Natural Science Foundation of Qingdao City (Grant No. 04-2-JZP-8) 相似文献
9.
An amperometric glucose biosensor was developed based on the immobilization of glucose oxidase in the organically modified
silicate (ormosil)-polyvinyl acetate (PVA) matrix onto a Prussian Blue (PB)-modified glassy carbon electrode. A higher stability
PB-modified electrode was prepared by the electrochemical deposition of FeCl3, K3[Fe(CN)6] and ethylenediamine tetraacetic acid (EDTA) under cyclic voltammetric (CV) conditions. The effects of the potential range
of CV conditions, electrolyte cations, applied potential, pH, temperature and co-existing substances were investigated. The
detection limit of the glucose biosensor was 8.1 μmol·L−1 (S/N = 3) with a linear range from 20 μmol·L−1 to 2 mmol·L−1 (R = 0.9965). The biosensor presented a fast response and good selectivity. Additionally, excellent reproducibility and stability
of the biosensor were observed.
Supported by the National High Technical Development Project (863 project) Foundation (Grant No. 2006AA09Z160) and the National
Natural Science Foundation of China (Grant No. 20775064) 相似文献
10.
JiaGao Cheng WeiLiang Zhu YanLi Wang XiuHua Yan Zhong Li Yun Tang HuaLiang Jiang 《中国科学B辑(英文版)》2008,51(8):768-775
The M2 protein from influenza A virus is a tetrameric ion channel. It was reported that the permeation of the ion channel is correlated with the hydrogen bond network among His37 residues and the cation-π interactions between His37 and Trp41. In the present study,the hydrogen bonding network of 4-methyl-imidazoles was built to mimic the hydrogen bonds between His37 residues,and the cation-π interactions between 4-methyl-imidazolium and indole systems were selected to represent the interac-tions between His37 and Trp41. Then,quantum chemistry calculations at the MP2/6-311G level were carried out to explore the properties of the hydrogen bonds and the cation-π interactions. The calcula-tion results indicate that the binding strength of the N-H···N hydrogen bond between imidazole rings is up to -6.22 kcal·mol-1,and the binding strength of the strongest cation-π interaction is up to -18.8 kcal·mol-1(T-shaped interaction) or -12.3 kcal·mol-1(parallel stacking interaction). Thus,the calcu-lated binding energies indicate that it is possible to control the permeation of the M2 ion channel through the hydrogen bond network and the cation-π interactions by altering the pH values. 相似文献
11.
A new tripodal rhodamine B derivative 2 was designed and synthesized by tripodal trialdehyde and rhodamine B hydrazide for
the first time. This derivative could be used as a fluorescent chemosensor for the selective and sensitive determination of
copper(II) in Tris-HCl buffer and ethanol aqueous mixed media. Under the optimum conditions described herein, fluorescence
enhancement at 557/577 nm was linearly related to the concentration of copper(II) in the range of 0.10 to 10.00×10−5 mol·L−1, with a correlation coefficient of R
2=0.9964 (n=15) and a detection limit of 1.129×10−7 mol·L−1 (the relative standard deviation for five repeated measurements at 4.00×10−5 mol·L−1 Cu(II) was 2.2%). The absorbance measurements at 557 nm were linearly related to the concentration of Cu(II) in the range
of 0.50 to 25.00×10−5 mol·L−1, with a correlation coefficient of R
2=0.9948 (n=13) and a detection limit of 3.338×10−7mol·L−1.
Supported by the Foundation of the Governor of Guizhou Province, China (Grant No. 200617) and the Talented Person Foundation
of Guizhou University (Grant No. 2007039) 相似文献
12.
The potential energy curves for the X1∑ g, B1△g and B′1∑ g states of C2 have been studied by using MRCI and approximate CI methods, and are benchmarked against the calculations of full configuration interaction (FCI). The results obtained by MRCI method agree with the FCI very well, and even are accurate enough to compare other approximate methods as benchmark, when the calculations of FCI are not feasible. The approximate CI methods mentioned in this paper are reliable for treating chemical problems. 相似文献
13.
Niu HaiJun Wang Wen Huang YuDong Zhang YunDong Zhang YunJun Bai XuDuo Liu Yuan 《中国科学B辑(英文版)》2007,50(2):230-237
PolySchiff base containing triphenylamine has been synthesized by polycondensation and character-ized by FT-IR,NMR,UV-visible spectrometer. Measurements of the third-order optical nonlinear sus-ceptibility χ(3) by Z-scan technique have shown that the large nonlinearity is dominated by the two-photon absorption in PSB. The sign and size of real part Reχ(3) ,nonlinear refractive index n2 have been measured with the condition of 532 nm,8 ns-duration pulses to be -1.23×10-10 esu,-3.06×10-12 esu;nonlinear absorption index β and size of image part Imχ(3) to be 3.63×10-10 m/W,1.15×10-11 esu,respec-tively,so the third-order nonlinear susceptibility χ(3) is 1.19×10-11 esu. The value is larger than other polymers reported. PSB is self-focusing material and has potential application in nonlinear optic field. 相似文献
14.
When trypsin reacts with Herring sperm DNA (hsDNA), Salmon sperm DNA (sDNA), and Calf thymus DNA (ctDNA) to form a complex,
the resonance Rayleigh scattering (RRS) was remarkably enhanced and new RRS spectra appear. These new spectra have similar
characteristics of RRS spectra. The maximum RRS peaks are at 307 nm (hsDNA, sDNA) and 290 nm (ctDNA), and other peaks are
at 350 nm. The scattering intensity is proportional to the concentration of DNA or trypsin; so this intereaction can be used
to determine trypsin using DNA or DNA using trypsin. In the determination of DNA using trypsin, the linear ranges for hsDNA,
sDNA, and ctDNA are 0–2.3, 0–2.5, and 0–1.9 μg·mL−1, and the detection limits are 0.4, 0.7, and 1.1 ng·mL−1, respectively. In the determination of trypsin using hsDNA, the linear range is 0–30.0 μg·mL−1, and the detection limit is 39.0 ng·mL−1. In this paper, the intereaction conditions were optimized. The affecting factors, chemical properties of the complex, and
the composition ratio of trypsin with DNA were investigated. Using trypsin as RRS probe, a sensitive method for the determination
of trace amounts of DNA was developed.
Translated from Chemical Journal of Chinese Universities, 2006, 27(3) (in Chinese) 相似文献
15.
Denitrification in tidal flat sediment, Yangtze estuary 总被引:5,自引:0,他引:5
Wang DongQi Chen ZhenLou Xu ShiYuan Da LiangJun Bi ChunJuan Wang Jun 《中国科学B辑(英文版)》2007,50(6):812-820
Sediment denitrification rates at six Yangtze River estuary tidal flat locations (mudflats and salt marshes) were measured
from July 2003 to October 2004. In winter and summer, spatial distribution of denitrification rates was not great in the Yangtze
estuary, while in spring and autumn, denitrification rates had a great spatial distribution because of the human activity
effect. The temporal change of denitrification rates was greater. They ranged from 0.2 to 36.4 μmolN·m−2·h−1, and were higher in the summertime. The annual average of sediment denitrification rate was 18.2±12.3 μmolN·m−2·h−1 in the middle tidal flat and 15.1±9.45 μmolN·m−2·h−1 in the low tidal flat in the Yangtze estuary. Data analysis indicated that the temperature was the primary factor controlling
the process of denitrification (significant positive correlation, P<0.01); at the same time, the content of sediment total nitrogen (TN) and the molar ratio of sediment carbon and nitrogen
(C/N) had significant positive correlation (P<0.05) and negative correlation (P<0.05) with denitrification rates, respectively. In the Yangtze estuary, increasing of water salinity had no significant inhibition
of denitrification because of the wide change range of water salinity.
Supported by the National Natural Science Foundation of China (Grant Nos. 40173030, 40571006 and 40131020), the Science &
Technology Department of Shanghai (Grant Nos. 05DZ120007 and 05JC14059) and China Postdoctoral Science Foundation. 相似文献
16.
Performance of sulfate-dependent anaerobic ammonium oxidation 总被引:4,自引:0,他引:4
The performance of sulfate-dependent anaerobic ammonium oxidation was studied. The results showed that both SO4
2− and NH4
+ were chemically stable under anaerobic conditions. They did not react with each other in the absence of biological catalyst
(sludge). The anaerobic digested sludge cultivated in an anaerobic reactor for three years took on the ability of oxidizing
ammonium with sulfate anaerobically. The average reduction of sulfate and ammonium was 71.67 mg·L−1 and 56.82 mg·L−1 at high concentrations. The reaction between SO4
2− and NH4
+ was difficult, though feasible, due to its low standard Gibbs free energy change. The experiment demonstrated that high substrate
concentrations and low oxidation-reduction potential (ORP) may be favourable for the biological reaction.
Supported by the National Natural Science Foundation of China (Grant No. 30770039) and the High-tech Research and Development
Program of China (Grant No. 2006AA06Z332) 相似文献
17.
Ping Zhao Mei Wang ShuPing Zhang SiChang Shao XiaoYu Sun SiDe Yao ShiLong Wang 《中国科学B辑(英文版)》2008,51(9):872-877
Due to the nontoxicity and efficient anti-cancer activity, more and more attention has been paid to N-glycoside compounds. Laser photolysis of N-(α-D-glucopyranoside) salicyloyl hydrazine (NGSH) has been performed for the first time. The research results show that NGSH has
high photosensitivity and is vulnerable to be photo-ionized via a monophotonic process with a quantum yield of 0.02, generating
NGSH+· and hydrated electrons. Under the aerobic condition of cells, the hydrated electrons are very easy to combine with oxygen
to generate 1O2 and O2
−, both of which are powerful oxidants that can kill the cancer cells. In addition, NGSH+· can be changed into neutral radicals by deprotonation with a pK
a value of 4.02 and its decay constant was determined to be 2.55×109dm3·mol−1·s−1. NGSH also can be oxidized by SO4
−· with a rate constant of 1.76×109 dm3·mol−1·s−1, which further confirms the results of photoionization. All of these results suggest that this new N-glycoside compound might be useful for cancer treatment.
The same contribution to the work
Supported by the National Natural Science Foundation of China (Grant Nos. 30570376 and 50673078) and Shanghai Project (Grant
Nos. 06JC14068 and 08ZZ21) 相似文献
18.
An accurate three-dimensional potential energy surface for the He-Na<Subscript>2</Subscript> complex
An accurate three-dimensional potential energy surface (PES) for the He-Na2 van der Waals complex was calculated at the coupled cluster singles-and-doubles with noniterative inclusion of connected
triple (CCSD(T)) level of theory. A mixed basis set, aug-cc-pVQZ for the He atom and cc-pCVQZ for the sodium atom, and an
additional (3s3p2d1f) set of midbond functions were used. The computed interaction energies in 819 configurations were fitted
to a 96-parameter analytic potential model by least squares fitting. The PES has two shallow wells corresponding to the T-shaped
structure and the linear configuration, which are located at 12.5a
0 and 14 a
0 with depths of 1.769 and 1.684 cm−1, respectively. The who potential energy surface exhibits weak anisotropy. Based on the fitted PES, state-to-state differential
cross sections were calculated.
Supported by the Natural Science Foundation of Anhui Educational Committee (Grant No. 2006kj072A) and the Natural Science
Foundation of Anhui Province (Grant No. 070416236) 相似文献
19.
Samaria-doped ceria Ce0.8Sm0.2O2−δ
(SDC) and SmFe0.7Cu0.3−x
Ni
x
O3 have been synthesized by the sol-gel method and characterized by X-ray diffraction (XRD), transmission electron microscopy
(TEM) and scanning electron microscopy (SEM). The electrochemical synthesis of ammonia was investigated at atmospheric pressure
and low temperature, using the SFCN materials as the cathode, a Nafion membrane as the electrolyte, nickel-doped SDC (Ni-SDC)
as the anode and silver-platinum paste as the current collector. Ammonia was synthesized from 25 to 100°C when the SFCN materials
were used as cathode, with SmFe0.7Cu0.1Ni0.2O3 giving the highest rates of ammonia formation. The maximum rate of evolution of ammonia was 1.13 × 10−8 mol·cm−2·s−1 at 80°C, and the current efficiency reached as high as 90.4%.
Supported by the National Natural Science Foundation of China (Grant No. 20863007) 相似文献
20.
Limbut W Hedström M Thavarungkul P Kanatharana P Mattiasson B 《Analytical and bioanalytical chemistry》2007,389(2):517-525
A capacitive biosensor for the detection of bacterial endotoxin has been developed. Endotoxin-neutralizing protein derived
from American horseshoe crab was immobilized to a self-assembled thiol layer on a biosensor transducer (Au). Upon injection
of a sample containing endotoxin, a decrease in the observed capacitive signal was registered. Endotoxin could be determined
under optimum conditions with a detection limit of 1.0 × 10−13 M and linearity ranging from 1.0 × 10−13 to 1.0 × 10−10 M. Good agreement was achieved when applying endotoxin preparations purified from an Escherichia coli cultivation to the capacitive biosensor system, utilizing the conventional method for quantitative endotoxin determination,
the Limulus amebocyte lysate test as a reference. The capacitive biosensor method was statistically tested with the Wilcoxon signed rank test, which proved
the system is acceptable for the quantitative analysis of bacterial endotoxin (P < 0.05).
Figure The flow-injection capacitive biosensor system and the capacitive properties of the transducer surface, where CSAM is the capacitance change of the self-assembled thiol monolayer, CP is the capacitance change of the protein layer, Ca is the capacitance change of the analyte layer and CTotal is the total capacitance change measured at the working electrode/solution interface (modified from Limbut et al., 2006.
Biosens Bioelectron 22: 233-240) 相似文献