排序方式: 共有98条查询结果,搜索用时 31 毫秒
61.
Collin T. Zahler Hongyu Zhou Dr. Alireza Abdolvahabi Rebecca L. Holden Sanaz Rasouli Prof. Peng Tao Prof. Bryan F. Shaw 《Angewandte Chemie (International ed. in English)》2018,57(19):5364-5368
Determining whether a protein regulates its net electrostatic charge during electron transfer (ET) will deepen our mechanistic understanding of how polypeptides tune rates and free energies of ET (e.g., by affecting reorganization energy, and/or redox potential). Charge regulation during ET has never been measured for proteins because few tools exist to measure the net charge of a folded protein in solution at different oxidation states. Herein, we used a niche analytical tool (protein charge ladders analyzed with capillary electrophoresis) to determine that the net charges of myoglobin, cytochrome c, and azurin change by 0.62±0.06, 1.19±0.02, and 0.51±0.04 units upon single ET. Computational analysis predicts that these fluctuations in charge arise from changes in the pKa values of multiple non‐coordinating residues (predominantly histidine) that involve between 0.42–0.90 eV. These results suggest that ionizable residues can tune the reactivity of redox centers by regulating the net charge of the entire protein–cofactor–solvent complex. 相似文献
62.
Polyaniline (PANI) nanofibres were synthesised by the chemical oxidative polymerisation method using ammonium peroxydisulphate (APS) as an oxidant/initiator. In this work, a surfactant-assisted method without shaking and stirring was used for the synthesis of PANI nanofibres. The effect was investigated of various parameters such as monomer/oxidant ratio, polymerisation temperature, and the presence of surfactant (Triton X-100 as a non-ionic surfactant) on the morphology and electrical conductivity of nanofibres. The morphology of PANI nanofibres was characterised by scanning electron microscopy and transmission electron microscopy. The results demonstrate that the morphology of PANI nanofibres was significantly influenced by the aniline/APS mole ratio, polymerisation temperature and presence of the surfactant during synthesis. The results showed that more regular and consistent nanofibres were obtained using a monomer/oxidant ratio of 4 at ambient temperature of polymerisation. PANI nanofibres with diameters in the range of 10?C100 nm and length up to several ??m were obtained. PANI nanofibres were also characterised using FTIR and UV-VIS absorption spectroscopy. The electrochemical behaviour of PANI nanofibres was studied by cyclic voltammetry. It was found that the electrical conductivity of PANI nanofibres increased with the increasing monomer/oxidant ratio and decreasing polymerisation temperature, respectively. 相似文献
63.
Rahimeh Hajinasiri Zinatossadat Hossaini Faramarz Rostami‐Charati 《Heteroatom Chemistry》2011,22(5):625-629
Ionic liquids such as 1,3‐dialkylimidazolium bromides make excellent solvents for synthesis of α‐aminophosphonates from aldehydes, amines, and phosphites. The ionic liquids are successfully regenerated and reused. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:625–629, 2011; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20724 相似文献
64.
In this paper, a simple and accurate method based on Z-scan and parallel moiré deflectometry for measuring the focal length of microlenses is reported. A laser beam is focused by one lens and is re-collimated by another lens, and then strikes a parallel moiré deflectometer. In the presence of a microlens near the focal point of the first lens, the radius of curvature of the beam is changed; the parallel moiré fringes are formed only due to the beam divergence or convergence. The focal length of the microlens is obtained from the moiré fringe period graph without the need to know the position of the principal planes. This method is simple, more reliable, and completely automated. The implementation of the method is straightforward. Since a focused laser beam and Z-scan in free space are used, it can be employed for determining small focal lengths of small size microlenses without serious limitation on their size. 相似文献
65.
G. A. Afrouzi S. H. Rasouli 《NoDEA : Nonlinear Differential Equations and Applications》2009,16(6):717-730
In this work, motivated by Wu (J Math Anal Appl 318:253–270, 2006), and using recent ideas from Brown and Wu (J Math Anal
Appl 337:1326–1336, 2008), we prove the existence of nontrivial nonnegative solutions to the following nonlinear elliptic
problem:
$\left\{{ll} -\Delta_{p}u+m(x)\,u^{p-1}=\lambda \,a(x)\, u^{\alpha-1}+b(x)\,u^{\beta-1}, & x \in \Omega,\\ u=0, & x\in\partial\Omega. \right.$\left\{\begin{array}{ll} -\Delta_{p}u+m(x)\,u^{p-1}=\lambda \,a(x)\, u^{\alpha-1}+b(x)\,u^{\beta-1}, & x \in \Omega,\\ u=0, & x\in\partial\Omega. \end{array}\right. 相似文献
66.
Majid Rasouli Disfani Keivan Vafi Mohammad Sadegh Abrishamian 《Applied Physics A: Materials Science & Processing》2011,103(3):765-769
The dyadic Green’s function of a PEMC cylinder is derived with the aid of the principle of scattering superposition and Ohm–Rayleigh
method. The PEMC boundary conditions are presented in dyadic form and it shows that how the impedance parameter of PEMC and
cross-polarized fields appear in the Green’s function. The asymptotic expansions of the dyadic function is calculated in order
to attain a closed form for the electrical field. 相似文献
67.
Saeedeh Kamrani Saeed Rasouli Heikalabad 《International Journal of Theoretical Physics》2018,57(11):3340-3358
In this paper, a unique gate is presented for the design of reversible flip-flops in quantum-dot cellular automata technology. The proposed gate is implemented with multiplexer, three-input Majority gate and XOR gate. The proposed gate has four input lines and four output lines. This gate is designed without garbage outputs. In other words, each output determines the function of each of flip-flops. The proposed structure is evaluated by the QCADesigner. The result of the simulation represents that the operations of the proposed structure is as expected and all functions are correct. Also, the evaluation results show that the proposed structure has significant improvement in area, cell numbers and delay compared to the previous structures. QCAPro tool is used to estimate energy consumption of the proposed structure. 相似文献
68.
We study the gravitational collapse of a star with barotropic equation of state p = wρ in the context of f(R){f({\mathcal R})} theories of gravity. Utilizing the metric formalism, we rewrite the field equations as those of Brans-Dicke theory with vanishing
coupling parameter. By choosing the functionality of Ricci scalar as f(R)=aRm{f({\mathcal R})=\alpha{\mathcal R}^{m}} , we show that for an appropriate initial value of the energy density, if α and m satisfy certain conditions, the resulting singularity would be naked, violating the cosmic censorship conjecture. These conditions
are the ratio of the mass function to the area radius of the collapsing ball, negativity of the effective pressure, and the
time behavior of the Kretschmann scalar. Also, as long as parameter α obeys certain conditions, the satisfaction of the weak energy condition is guaranteed by the collapsing configuration. 相似文献
69.
Pouya Dastmalchi Nosrat Granpayeh Majid Rasouli Disfani 《Applied Physics A: Materials Science & Processing》2011,103(3):741-744
We have investigated the performance of a nano-optical directional coupler based on gap plasmon waveguides. The coupler consists
of two waveguides having a localized coupled plasmon propagating between two semi-cylindrical surfaces. After introducing
a fundamental mode of studied waveguides, effects of the structure parameters on the coupling length are shown. Simulation
results of the coupler obtained by the compact-2D finite-difference time-domain (FDTD) method comply with those derived by
an analytic method with the aid of the finite-element frequency-domain (FEFD) software package of COMSOL. 相似文献
70.
Papizadeh M Ardakani MR Motamedi H Rasouli I Zarei M 《Applied biochemistry and biotechnology》2011,165(3-4):938-948
Crude oil-contaminated soil samples were gathered across Khuzestan oilfields (National Iranian South Oil Company, NISOC) consequently experienced a screening procedure for isolating C-S targeted dibenzothiophene-biodegrading microorganisms with previously optimized techniques. Among the isolates, a bacterial strain was selected due to its capability of biodegrading dibenzothiophene in a C-S targeted manner in aqueous phases and medium mostly consisting of separately biphasic water-gasoline. The 16S rDNA of the isolate was amplified using eubacterial-specific primers and then sequenced. Based on sequence data analysis, the microorganism, designated NISOC-04, clustered most closely with the members of the genus Stenotrophomonas. Gas chromatography indicated that Stenotrophomonas sp. NISOC-04 utilizes 82% of starting 0.8 mM dibenzothiophene within a 48-h-long exponential growth phase. Growth curve analysis revealed the inability of Stenotrophomonas sp. NISOC-04 to utilize dibenzothiophene (DBT) as the exclusive carbon or carbon/sulfur source. Gibbs' assay showed no 2-hydroxy biphenyl accumulation, but HPLC confirmed the presence of 2-hydroxy biphenyl as the final product of DBT desulfurization. Under sulfur starvation, Stenotrophomonas sp. NISOC-04 produced a huge biomass with untraceable sulfur and utilized atmospheric insignificant sulfur levels. 相似文献
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