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951.
Ali Asghar Rastegari Abdol-Khalegh Bordbar Vajihe Mehnati-Najafabadi 《Cellulose (London, England)》2010,17(6):1213-1225
The present study evaluates the binding of cetylpyridinium chloride (CPC) with cellulase in various experimental conditions
using potentiometric, fluorescence spectroscopy and turbidimetric techniques. The analysis of binding curves revealed the
existence of two sets of binding sets for CPC. The binding parameters were estimated and interpreted in terms of structural
viewpoints of cellulase. The observation of turbidity suggests that CPC molecules individually nucleate around cellulase/CMC
complex to form micelle-like structures. Fluorescence spectroscopy analysis of cellulase/CMC-surfactant system showed that
these complexes could be compact to elucidate the mechanism of binding cellulase/CMC complex to CPC. The differential response
of the enzyme/CMC to surfactant, indicates that the interaction on the complex surface is strongly ionic and hydrophobic(cooperative)
in nature. A sequencing analysis was also conducted on β-1, 4-endoglucanase from A. niger (EglA) and others from family 12 in order to examine the nature of interaction involved in binding process and structure
of carbohydrate-protein complexes. The results suggest that the conserved residues are located in a more hydrophobic microenvironment
and apolar area energy is more than polar within enzyme structure. 相似文献
952.
ElShazali Ahmed Mohamed Nahid Abdelraheem Ali Salma Hashim Ahmed Isam A. Mohamed Ahmed Elfadil E. Babiker 《Radiation Physics and Chemistry》2010,79(7):791-796
Whole and dehulled flours of millet cultivars Ashana and Dembi were stored for 30 and 60 days before and after radiation and/or cooking. Phytic acid and polyphenols contents were assayed for all treatments. The results revealed that the storage period was found to have no effect on phytate and polyphenols contents. Moreover, dehulling of the grains reduced more than 50% of phytate and polyphenols of both cultivars. Cooking of the raw whole and dehulled flour significantly (P≤0.05) reduced phytate and polyphenols contents for both cultivars. Radiation process alone had no effect on phytate and polyphenols contents but when followed by cooking significantly (P≤0.05) reduced the level of such antinutrients for the whole and dehulled flour of both cultivars. Dehulling alone significantly (P≤0.05) decreased Ca and P content but slightly decreased Fe content. Radiation alone or in combination with cooking was found to have slight effect on minerals content of the whole and dehulled raw flour for both cultivars. Cooking alone or in combination with radiation of whole or dehulled raw flour significantly (P≤0.05) improved the extractable Ca but had no significant (P≤0.05) effect on extractable P and Fe for both cultivars. 相似文献
953.
Ali Haider Zareen Akhter Humaira Masood Siddiqi Edward R. T. Tiekink 《Journal of chemical crystallography》2010,40(5):397-401
Abstract
The molecule of 4-aminobenzohydrazide is essentially planar and geometric parameters conform to literature precedents. Supramolecular N–H···O and N–H···N interactions combine to link molecules of 4-aminobenzohydrazide into a three-dimensional network. Weaker N–H···N and N–H···π interactions consolidate the structure. The compound crystallizes in the monoclinic space group P21/n with a = 5.411(2) ?, b = 14.000(6) ?, c = 9.894(4) ?, β = 103.917(7)o, and Z = 4. 相似文献954.
采用初湿浸渍和溶胶凝胶法分别制备了Li/MgO催化剂和Li/MgO纳米催化剂. 比较两种Li/MgO催化剂对于甲烷氧化偶联反应的催化性能. 采用X射线衍射、BET吸附和透射电镜进行了表征.在973-1073 K和总压力为101 kPa下对催化剂进行了测试. 实验结果表明,Li/MgO纳米催化剂比普通催化剂对于甲烷氧化偶联反应表现为更高的甲烷转换率,较高选择性和较高的的主要产品(乙烷和乙烯)的产率. 相似文献
955.
Loredo A Plessy A El Hafidi A Hamzaoui N 《The Journal of the Acoustical Society of America》2011,129(4):1905-1918
A numerical vibroacoustic model that can manage multilayered plates locally covered with damping patches is presented. All the layers can have an on-axis orthotropic viscoelastic behavior. Continuity of displacements and transverse shear stresses at each interface is enforced, which permits to write the entire displacement field in function of the displacements of the--common--first layer, leading to a two-dimensional plate model. The problem is then discretized by Rayleigh-Ritz's method using a trigonometric basis that includes both sine and cosine functions in order to treat various boundary conditions. The excitation can be of mechanical kind (concentrated or distributed forces) or of acoustic kind (plane wave of any incidence, diffuse field, etc.). The model permits to compute different vibroacoustic indicators: the mean square velocity of the plate, the radiation efficiency, and the transmission loss. Comparisons between the present model and numerical results from literature or finite element computations show that the model gives good results in both mechanical and acoustical aspects. Then, a comparison of the effects of different distributions of patches is presented. The role of the surface covering rate is first discussed, followed by a study involving different geometries for the same surface covering rate. 相似文献
956.
Seyed Ali Salehizadeh Dariush Souri 《Journal of Physics and Chemistry of Solids》2011,72(11):1381-1385
The glass transition temperature dependence to heating rate and therefore the activation energy (ΔH?) of the glass transition of (60-x)V2O5–xNiO–40TeO2 oxide glasses with 0≤x≤20 (in mol%) were investigated at heating rates φ (=3 6, 9, 10 and 12 K/min) using differential scanning calorimetry (DSC). The heating rate dependence of Tg was used to investigate the applicability of different theoretical models describing the glass transition. Using the application of Moynihan and Kissinger et al. models to the present data, different values of (ΔH?) at each different heating-rate regions were obtained. The fragility parameter (m=ΔH?/R Tg) was ∼24.98 for x=10 mol%, suggesting that this glass may be considered as a rather strong glass (fragility index m∼>20 is an indication of fragile glass). Also the compositional dependence of Tg and ΔH? was investigated. 相似文献
957.
The generation of aerodynamic sound by the interaction of flow at a Reynolds number of 150 and a Mach number of 0.2 with a rigid square cylinder attached to a rigid thin flat plate is numerically investigated. When the length of the plate is varied from L=0.5D to 6D, where D is the side length of the square cylinder, the results can be grouped into three distinct regimes. For the first regime (L?D), the sound levels decrease with increasing plate length. A 3 dB sound reduction is obtained when the length of the plate is D. For the second regime (1.25D?L?4.75D), the sound levels increase with increasing plate length. For the third regime (5D?L?6D), the sound levels decrease as the length of the plate increases but the levels are higher than for the other regimes. Results also show that the lift fluctuation is the dominant sound source. These acoustic results can be explained in terms of the fluid mechanics occurring in the near wake of the cylinder. 相似文献
958.
Yang TY Balakrishnan J Volmer F Avsar A Jaiswal M Samm J Ali SR Pachoud A Zeng M Popinciuc M Güntherodt G Beschoten B Özyilmaz B 《Physical review letters》2011,107(4):047206
We report on the first systematic study of spin transport in bilayer graphene (BLG) as a function of mobility, minimum conductivity, charge density, and temperature. The spin-relaxation time τ(s) scales inversely with the mobility μ of BLG samples both at room temperature (RT) and at low temperature (LT). This indicates the importance of D'yakonov-Perel' spin scattering in BLG. Spin-relaxation times of up to 2 ns at RT are observed in samples with the lowest mobility. These times are an order of magnitude longer than any values previously reported for single-layer graphene (SLG). We discuss the role of intrinsic and extrinsic factors that could lead to the dominance of D'yakonov-Perel' spin scattering in BLG. In comparison to SLG, significant changes in the carrier density dependence of τ(s) are observed as a function of temperature. 相似文献
959.
960.
Nanoplates of the three-dimensional coordination polymer, {[Cd(3)(3-pyc)(4)(N(3))(2)(H(2)O)](n) (1), 3-pyc(-)=pyridine-3-carboxylate), have been synthesized by a sonochemical process and characterized by scanning electron microscopy, X-ray powder diffraction, IR spectroscopy and elemental analyses. Cadmium(II) oxide nanoparticles were prepared from thermal decomposition in oleic acid and direct calcination of compound 1 at different temperatures. The thermal stability of nano-sized compound 1 was studied by thermal gravimetric (TG) and differential thermal analyses (DTA). Results show that the size and morphology of the CdO nanoparticles are dependent upon the particles size of compound 1 and the thermolysis temperature. A decrease in the particle size of compound 1 leads to a decrease in the particle size of the CdO, while an increase in the processing temperature leads to an increase in the particle size of the produced cadmium(II) oxide nano-particles. 相似文献