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201.
Living systems are open systems, where the laws of nonequilibrium thermodynamics play the important role. Therefore, studying living systems from a nonequilibrium thermodynamic aspect is interesting and useful. In this review, we briefly introduce the history and current development of nonequilibrium thermodynamics, especially that in biochemical systems. We first introduce historically how people realized the importance to study biological systems in the thermodynamic point of view. We then introduce the development of stochastic thermodynamics, especially three landmarks: Jarzynski equality, Crooks’ fluctuation theorem and thermodynamic uncertainty relation. We also summarize the current theoretical framework for stochastic thermodynamics in biochemical reaction networks, especially the thermodynamic concepts and instruments at nonequilibrium steady state. Finally, we show two applications and research paradigms for thermodynamic study in biological systems. 相似文献
202.
A practical copper-catalyzed N-arylation of NH-containing heterocycles with arenediazonium tetrafluoroborates has been developed using CuCl as catalyst and K2CO3 as additive under ligand-free conditions. This reaction system has wide substrate scope including imides, 1H-pyrazole, 1H-tetrazoles, 1,2-benzisothiazol-3(2H)-one, and related sulfonamides and gives moderate to excellent yields (up to 95%) of the desired products. This strategy is very general, simple, environmentally friendly, and tolerant of oxygen. 相似文献
203.
Hongliang Dai Yiming Fu J.H. Yang 《力学学报》2007,23(1):55
Analytical studies on electromagnetoelastic behaviors are
presented for the functionally graded piezoelectric material (FGPM) solid
cylinder and sphere placed in a uniform magnetic field and subjected to the
external pressure and electric loading. When the mechanical, electric and
magnetic properties of the material obey an identical power law in the
radial direction, the exact displacements, stresses, electric potentials and
perturbations of magnetic field vector in the FGPM solid cylinder and sphere
are obtained by using the infinitesimal theory of electromagnetoelasticity.
Numerical examples also show the significant influence of material
inhomogeneity. It is interesting to note that selecting a specific value of
inhomogeneity parameter can optimize the electromagnetoelastic
responses, which will be of particular importance in modern engineering
designs. 相似文献
204.
In this paper, the “FLIC” difference method with triangular mesh is adopted to numerically simulate the regular and Mach reflections
that occur when a shock wave pass around a wedge. The compuational result is compared with the shock tube experimental results
of G. Ben-Dor and I. I. Glass. The comparison shows that the position, shape of shock wave and height of Mach stem all show
a good agreement. Consequently, the “FLIC” difference method with triangular mesh is quite satisfactory in numerical simulation
of the regular and Mach reflections. 相似文献
205.
本文应用弹塑性理论研究了被测试样的屈服强度、应力场对钻孔法测量残余应力过程中钻孔附加应变的影响,使用简化的理论模型推导了低速旋转钻头钻孔产生附加应变的一般表达式.结果表明钻孔引入的附加应变与被测试样的原始残余应力状态有关,随应力水平增加而增大,在压应力减小到某一临界值σ时,钻孔附加应变为零。在 Ly12铝合金上的实验测量结果与理论结果一致。 相似文献
206.
Xin Ping Ouyang Pan Zhang Chun Mei Tan Yong Hong Deng Dong Jie Yang Xue Qing Qiu 《中国化学快报》2010,21(12):1479-1481
<正>Lignosulfonate with low polydispersity index of 1.178-1.210 was isolated by gel column chromatography of Sephacryl S-100 eluted with 0.2 mol/L of NaNO_3 aqueous solution,whereas nearly monodisperse ligosulfonate fraction with polydispersity of 1.0(57 can be obtained after chromatographic separation twice.This method provides an available approach to investigate the structure and characteristics of lignosulfonate. 相似文献
207.
Keller TF Müller M Ouyang W Zhang JT Jandt KD 《Langmuir : the ACS journal of surfaces and colloids》2010,26(24):18893-18901
We report a templating effect of uniaxially oriented melt-drawn polyethylene (MD-PE) films on α-helical poly(L-lysine)/poly(styrenesulfonate) (α-PLL/PSS) complexes deposited by the layer-by-layer (LBL) method. The melt-drawing process induced an MD-PE fiber texture consisting of nanoscale lamellar crystals embedded in amorphous regions on the MD-PE film surface whereby the common crystallographic c axis is the PE molecular chain direction parallel to the uniaxial melt-drawing direction. The MD-PE film and the α-PLL/PSS deposit were analyzed by atomic force microscopy (AFM) and in situ attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) using polarized light as a complementary method. Both methods revealed that α-PLL/PSS complexes adsorbed at the MD-PE surface were anisotropic and preferentially oriented perpendicular to the crystallographic c direction of the MD-PE film. Quantitatively, from AFM image analysis and ATR-FTIR dichroism of the amide II band of the α-PLL, mean cone opening angles of 12-18° for both rodlike α-PLL and the anisotropic α-PLL/PSS complexes with respect to the PE lamellae width direction were obtained. A model for the preferred alignment of α-PLL along the protruding PE lamellae is discussed, which is based on possible hydrophobic driving forces for the minimization of surface free energy at molecular and supermolecular topographic steps of the PE surface followed by electrostatic interactions between the interconnecting PSS and the α-PLL during layer-by-layer adsorption. This study elucidates the requirements and mechanisms involved in orienting biomolecules and may open up a path for designing templates to induce directed protein adsorption and cell growth by oriented polypeptide- or protein-modified PE surfaces. 相似文献
208.
Jiang X Cao Y Wang Y Liu L Shen F Wang R 《Journal of the American Chemical Society》2010,132(43):15328-15333
Drug-lead synthesis through rapid construction of chiral molecular complexity around the biologically relevant framework using a highly efficient strategy is a key goal of organic synthesis. Molecules bearing a spirooxindole-type framework exhibit important bioactivities. Herein, we present a highly efficient and convenient strategy that allows rapid construction of unique optically active spiro[oxazoline-3,3'-oxindole]s through the organocatalyzed asymmetric synthesis of spirocyclic thiocarbamates via an aldol reaction. Preliminary biological evaluation of several of the spirooxazolines using a model of acute neuroinflammation revealed promising antipyretic activity and provided an opportunity to discover new antipyretic agents. 相似文献
209.
Jiang F Wang Y Hu X Shao N Na N Delanghe JR Ouyang J 《Journal of separation science》2010,33(21):3393-3399
The application of pore-gradient polyacrylamide gel electrophoresis (PG-PAGE) incorporated with carbon nanotube modified by Triton X-100 and carboxylation so as to improve the separation of human serum proteins is reported. The novel PG-PAGE was made by adding water-soluble single-walled carbon nanotubes (CNTs) when preparing the polyacrylamide gel. Significant improvements in separation of complement C3 protein and haptoglobin (Hp) in human serum were achieved. It was estimated that the interactions between the hydrophilic groups on the proteins and the surface of the CNTs result in different adsorption kinetics of complement C3 and Hp subtype on the nanoparticles incorporated in the gel, thus enhancing the separation of the two proteins in serum. This new CNT matrix-assisted PG-PAGE method for enhanced separation of complement C3 and Hp in human serum was successfully applied to distinguish the samples from liverish patients and healthy people. 相似文献
210.
In pH 1.99 sodium acetate-HCl buffer solutions at 60 °C, Rhodamine B exhibited a strong fluorescence peak at 584 nm using
an excitation wavelength of 548 nm. The fluorescence quenching occurred when Fe3O4 nanoparticles catalyzed H2O2 oxidation of Rhodamine B. Under the chosen conditions, the fluorescence intensity at 584 nm decreased when the concentration
of H2O2 increased. The fluorescence quenching intensity is linear with the concentration of H2O2 in the range of 10–200 nmol/L. Thus, a new and simple and sensitive nanocatalytic fluorescence method was proposed for the
determination of H2O2 in synthetic sample, with satisfactory results. 相似文献