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51.
Adam Liwo Jarosław Pillardy Rajmund Kaźmierkiewicz Ryszard J. Wawak Małgorzata Groth Cezary Czaplewski Stanisaw Ołdziej Harold A. Scheraga 《Theoretical chemistry accounts》1999,101(1-3):16-20
A united-residue model of polypeptide chains developed in our laboratories with united side-chains and united peptide groups
as interaction sites is presented. The model is designed to work in continuous space; hence efficient global-optimization
methods can be applied. In this work, we adopted the distance-scaling method that is based on continuous deformation of the original
rugged energy hypersurface to obtain a smoothed surface. The method has been applied successfully to predict the structures
of simple motifs, such as the three-helix bundle structure of the 10-58 fragment of staphylococcal protein A in de novo folding
simulations and more complicated motifs in inverse-folding simulations.
Received: 24 April 1998 / Accepted: 4 August 1998 / Published online: 2 November 1998 相似文献
52.
We study the variational equations for solitons in noncommutative scalar field theories in an even number of spatial dimensions. We prove the existence of spherically symmetric solutions for a sufficiently large noncommutativity parameter θ and we prove the absence of spherically symmetric solutions for small θ. 相似文献
53.
54.
Sylwia Studzińska Sandra Mounicou Joanna Szpunar Ryszard Łobiński Bogusław Buszewski 《Analytica chimica acta》2015
This text presents a novel method for the separation and detection of phosphorothioate oligonucleotides with the use of ion pair ultra high performance liquid chromatography coupled with inductively coupled plasma mass spectrometry The research showed that hexafluoroisopropanol/triethylamine based mobile phases may be successfully used when liquid chromatography is coupled with such elemental detection. However, the concentration of both HFIP and TEA influences the final result. The lower concentration of HFIP, the lower the background in ICP-MS and the greater the sensitivity. The method applied for the analysis of serum samples was based on high resolution inductively coupled plasma mass spectrometry. Utilization of this method allows determination of fifty times lower quantity of phosphorothioate oligonucleotides than in the case of quadrupole mass analyzer. Monitoring of 31P may be used to quantify these compounds at the level of 80 μg L−1, while simultaneous determination of sulfur is very useful for qualitative analysis. Moreover, the results presented in this paper demonstrate the practical applicability of coupling LC with ICP-MS in determining phosphorothioate oligonucleotides and their metabolites in serum within 7 min with a very good sensitivity. The method was linear in the concentration range between 0.2 and 3 mg L−1. The limit of detection was in the range of 0.07 and 0.13 mg L−1. Accuracy varied with concentration, but was in the range of 3%. 相似文献
55.
56.
This study describes the influence of melamine polyphosphate (MPP) flame retardant addition on layered structure of virgin sodium montmorillonite (MMT) in PA6/MMT system obtained in extrusion process. It was found that the extrusion of the PA6/MMT binary system in co‐rotating twin screw extruder gives intercalated clay nanocomposites, while during extrusion of ternary PA6/MMT/MPP composite, full exfoliation of clay was obtained in the system. Structure of the composites was proved utilizing wide angle X‐ray scattering and transmission electron microscopy techniques. Exfoliation of MMT in ternary PA6/MMT/MPP system was also confirmed by rheological studies (viscosity and creep measurements) which were carried out using rotational rheometer. Young's modulus of PA6/MMT/MPP was found to be ~25% greater comparing to PA6/MPP of the same filling level. Cone calorimetry experiments proved decrease of heat release rate peak of PA6/MMT/MPP by ~55% comparing to PA6/MPP with the same total filling level. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
57.
We study a collisionless kinetic equation describing density distribution function of the position and velocity of particles moving in a slab with finite thickness and with a partly diffusive boundary reflection. In particular, we deal with existence of an invariant density and with the convergence to the equilibrium. We also study the long time behavior of densities when the equilibrium does not exists. 相似文献
58.
The aim of the paper is to fill the gap between the general theoretical formulation of the constitutive relations for plastic spin and practical applications for proper prediction of material behavior at finite plastic deformations and anisotropic hardening. An approximation to the representation of the general constitutive equation for plastic spin is considered and the pertinent substructure corotational rate is applied to formulate the relation for rigid-plastic material with kinematic hardening. The simple shear traction problem is analysed and the proposed model is verified with the experimental results of Swift. The merits of the present proposal vis-à-vis the existing theories are discussed. 相似文献
59.
Direct aldol reactions of 4-methyl-1-piperidone, tropinone and granatanone (pseudopelletierine) take place spontaneously in the presence of water without any catalyst or additional reagents. The anti/syn-diastereoselectivity of the aqueous aldol reaction depends on the amount of water used. The syn-selectivity of the reaction is probably due to the thermodynamic control. Excellent atom economy and low E factors together with anti-selectivity as high as 98:2 for the tropinone aldol were obtained. 相似文献
60.
The paper presents elastic barrier materials developed at the INF which play a role of filling and fire barrier material at the same time in upholstery furniture, reducing the development and spread of fire on flammable materials. The presented results of flammability and biophysical tests confirm the comfort of products.The developed barrier materials use natural fibres (wool, flax FR) characterized by good air permeability, hygroscopicity, moisture transport, elimination of electrostatic charges and have effect on climate of interiors also when blended with thermostable fibres such as Polyacrylate. These flexible structures based on blend of natural fibres and thermostable fibres with at least two barrier effects i.e. durable resistance to fire, thermal insulation, control of electrostatic phenomena. 相似文献