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排序方式: 共有235条查询结果,搜索用时 15 毫秒
31.
Eshtiagh-Hosseini H Housaindokht MR Beyramabadi SA Tabatabaei SH Esmaeili AA Khoshkholgh MJ 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,78(3):1046-1050
A new N,N'-dipyridoxyl(1,4-butanediamine) [=H(2)BS] Schiff-base ligand and its Cu(II) salen complex, [Cu(BS)(H(2)O)(CH(3)OH)], were synthesized and characterized by IR, UV-vis, (1)H NMR, mass spectrometry and elemental analysis. Also, full optimization of the geometries, (1)H NMR chemical shifts (for the H(2)BS) and vibrational frequencies were calculated by using density functional theory (DFT) method. Structure of the H(2)BS ligand is not planar, i.e. two pyridine rings are not in the same plane. In the structure of the Cu complex, the Schiff-base ligand acts as a dianionic tetradentate ligand in N, N, O(-), O(-) manner. The coordinating atoms of BS(2-) occupy equatorial positions of the octahedral complex, where the H(2)O and CH(3)OH ligands locate at axial positions. The calculated results are in good agreement with the experimental data, confirming the suitability of the proposed and optimized structures for the H(2)BS ligand and its Cu complex. 相似文献
32.
Activation of a Photodissociative Ruthenium Complex by Triplet–Triplet Annihilation Upconversion in Liposomes 下载免费PDF全文
Sven H. C. Askes Azadeh Bahreman Dr. Sylvestre Bonnet 《Angewandte Chemie (International ed. in English)》2014,53(4):1029-1033
Liposomes capable of generating photons of blue light in situ by triplet–triplet annihilation upconversion of either green or red light, were prepared. The red‐to‐blue upconverting liposomes were capable of triggering the photodissociation of ruthenium polypyridyl complexes from PEGylated liposomes using a clinical grade photodynamic therapy laser source (630 nm). 相似文献
33.
Azadeh Kiani Ali Ghaffarinejad Seyed Abolfazl Seyedsadjadi Atiyeh Mansouri 《Electroanalysis》2020,32(2):281-290
In this study, an available and inexpensive graphite substrate, was easily modified with Ni/Cr nanoparticles via electrodeposition technique in a very short time (3 min) and used as an electrocatalyst for glucose oxidation in alkaline solution. Graphite electrode modified with Ni/Cr nanoparticles demonstrated an outstanding electrocatalytic performance to glucose oxidation in comparison to examined Ni‐based electrodes or even different materials in other reports. It is noteworthy to mention that adding a little Cr led to a synergistic effect with Ni; accordingly, the presence of Cr not only resulted in a greater adsorption of glucose molecules by chromium oxide but also boosted conductivity of the nickel oxide because of the enhancement of Ni(III) amount. The electrochemical studies were performed by cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The morphology and structure of catalyst layer was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray diffraction (XRD) and energy dispersive x‐ray spectroscopy (EDS). The linear range of the electrode by cyclic voltammetry was between 2–31 mM with a high sensitivity of 2094 μA cm?2 mM?1. The repeatability and reproducibility of the proposed electrode was examined in glucose solution which were 0.3 % and 4.7 %, respectively. According to the low cost, ease and fast preparation, good repeatability and high sensitivity, this electrode can be a good candidate for nonenzymatic glucose oxidation. 相似文献
34.
Four-point bend specimen is one of the most important specimens of the fracture mechanics because it can produce mixed modes I and II. Therefore, computation of stress intensity factors in this specimen is of practical interest. Several relations have been suggested that no one of them has completely considered the effects of the loading point and crack geometry. In this paper, mixed mode stress intensity factors of the bend specimen are computed by finite element method (FEM) and after validating by comparing with the available results in the literature, the results will be assessed to determine the effects of different crack location and loading distances from the middle of the specimen. Finally, two new coefficients comprising these effects are introduced. 相似文献
35.
36.
Smart pixels with smart illumination is a new concept in sensor array technology based on structured built-in illumination and optoelectronic feedback. It offers many new possibilities and potential advantages over more-traditional sensor arrays. We discuss an edge-detection system as an example of how smart illumination can advantageously be used to achieve a variety of functions. We also present initial experimental results from a fabricated chip based on this concept. The chip includes an integrated array of photodetectors and LED's. The output of each pixel can be controlled based on the feedback received by its dual detectors. 相似文献
37.
In recent years, polymer nanospheres have been considered as one of the most common materials in the drug delivery domain. In this research, polycaprolactone-polyethylene glycol (PCL-PEG) blend nanospheres were produced using the electrospray method to load doxorubicin. Also, these nanospheres can be used for injection in the treatment site by poloxamer-chitosan thermogel. In this research, PCL and PEG were used as raw materials to produce nanospheres. Then, doxorubicin was used for loading in nanospheres. The electrospray method was chosen as the method of nanosphere production. In the next step, poloxamer-chitosan thermogel was used for injection at the treatment site. In this method, Fourier transform infrared spectroscopy, scanning electron microscopy, and rheometer techniques were used to identify the compounds and properties of the obtained specimens. Also, the MTT test was used to investigate toxicity. The results showed that PCL-PEG polymer nanospheres were produced by loading doxorubicin using the electrospraying method with a diameter of 185 ± 23 nm. Also, these nanospheres were used for injection in the treatment site using poloxamer-chitosan thermogel. The amount of drug release in the PLX-CS (DOX-PCL-PEG)NSs was 63% in 144 h at medium pH 5.5. In the drug release system, the in-vitro method was utilized to study the release of PLX-CS (DOX-PCL-PEG) NSs. PCL-PEG nanospheres combined in poloxamer-chitosan thermogel polymer showed the controlled release of doxorubicin, therefore, the evaluated drug release system is considered a valuable perspective as an efficient and safe route for drug delivery in the target tissue and treating various types of cancer. This research can be used as a new method in drug delivery systems. 相似文献
38.
Kazem Bitaghsir Fadafan Seyed Kamal Tabatabaei 《The European Physical Journal C - Particles and Fields》2014,74(4):1-11
Nuclear effects in deep inelastic scattering at low $x$ are phenomenologically described changing the typical dynamical and/or kinematical scales characterizing the free nucleon case. In a holographic approach, this rescaling is an analytical property of the computed structure function $F_2(x,Q^2)$ . This function is given by the sum of a conformal term and of a contribution due to quark confinement, depending on IR hard-wall parameter $z_0$ and on the mean square distances, related to a parameter $Q^\prime $ , among quarks and gluons in the target. The holographic structure function per nucleon in a nucleus $A$ is evaluated showing that a rescaling of the typical nucleon size, $z_0$ and $Q^\prime $ , due to nuclear binding, can be reabsorbed in a $Q^2$ -rescaling scheme. The difference between neutron and proton structure functions and the effects of the longitudinal structure functions can also be taken into account. The obtained theoretical results favorably compare with the experimental data. 相似文献
39.
An efficient method for preparation of aryl nitriles—using [Pd{C6H2(CH2CH2 NH2)‐(OMe)2,3,4} (µ‐Br)]2 complex as an efficient catalyst and K4[Fe(CN)6] as a green cyanide source—from aryl bromides, aryl iodides and aryl chlorides under microwave irradiation has been reported. This complex has been demonstrated to be an active and efficient catalyst for this reaction. Using a catalytic amount of this synthesized palladium complex in DMF at 130 °C led to production of the cyanoarenes in excellent yields in short reaction times. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
40.
A gene encoding β-1,3-1,4-glucanase was cloned by polymerase chain reaction (PCR) from Bacillus subtilis MA139. Sequencing result showed 97% homology to the corresponding gene from Bacillus licheniformis. The open reading frame (ORF) of the gene contained 690 bp coding for a 226 amino-acid matured protein with the estimated
molecular weight of 24.44 kDa. The β-1,3-1,4-glucanase gene was subcloned into an expression vector of pET28a and expressed
in Escherichia coli BL21 and then purified by metal affinity chromatography using a nickel–nitrilotriacetic acid (Ni–NTA) column. The purified
β-1,3-1,4-glucanase demonstrated 24.05 and 12.52 U ml-1 activities for the substrates of barley β-glucan and lichenan, respectively, and the specific activities were 728.79 and
379.1 U mg-1 for them, respectively. The optimal temperature and pH of the purified enzyme were 40°C and 6.4, respectively. When barley
β-glucan was used as the substrate, K
m was 5.34 mg ml-1, and K
cat showed 7,206.71 S-1, thus the ratio of K
cat and K
m was 1,349.67 ml s-1 mg-1. The activity of β-1,3-1,4-glucanase was affected by a range of metal ions or ethylenediaminetetraacetic acid (EDTA). 相似文献