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排序方式: 共有300条查询结果,搜索用时 31 毫秒
1.
测定了在温度310.65K、323.15K和压力3.13~7.54MPa条件下的气液平衡数据,实验结果与文献值具有较好的一致性。用TRK状态方程对实验所得数据进行关联,取得了较满意的结果。 相似文献
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根据生物代谢状态方程和代谢反应一般表达式,解析由葡萄糖生成乙醇的生物代谢过程。结果表明,该过程是一个可达到热力学最大可能性的过程,该代谢过程的热力学最大可能性转化率为51.1%,方程的解与依据代谢途径直接核算的结果一致,说明这些代谢途径已实现了热力学上的最大可能性。研究表明由葡萄糖生成乙醇的代谢过程具有非连续的能级特征。研究结果为深入解析代谢过程的物理意义奠定了基础。 相似文献
3.
借用非平衡热力学理论,分析自然界水火运动的规律,得出结论——阴阳交感过程是熵减少过程,阴阳反作过程是熵增加过程;机体的许多阴阳变化也遵循同一规律。并在此基础上论证了新陈代谢过程是机体从外界输入负熵以抵消体内正熵产生的过程,从而推知阴阳交感现象发生的原因是新陈代谢。 相似文献
4.
目的 通过超声辅助大孔树脂对荆芥穗Schizonepetae Spica水提物中总黄酮和总酚类化合物进行富集并对比处理前后化合物含量及活性变化。方法 从7种不同类型树脂中筛选超声辅助最佳树脂型号,在吸附动力学和吸附热力学研究下,对超声温度、功率、上样质量浓度及解吸溶剂百分比等影响因素进行工艺优化。测定了优化处理前后各成分含量及活性变化。结果 动力学和热力学的研究表明,荆芥穗总黄酮适用于Langmuir模型,且吸附过程为自发吸热熵增,总酚则为自发放热熵减并适用于Freundlich模型,据此不同的吸附机制优化了2类成分同时富集的最佳工艺,在超声辅助AB-8大孔树脂,温度25 ℃、时间2.5 h,功率150 W,上样质量浓度0.1 g/mL,70%乙醇解吸附的过程下,荆芥穗水提物中总黄酮和总酚类化合物含量增加2~3倍,其单体成分的含量及抗氧化和神经氨酸酶抑制活性均显著增加。结论 超声辅助大孔树脂技术为荆芥穗总黄酮和总酚类成分的有效可行富集技术。 相似文献
5.
用反相气相色谱方法测定了16种溶剂在聚甲基丙烯酸丁酯(PBMA)中343 ̄433K范围内的无限稀释活度系数,并用周浩等的高分子溶液分子热力学模型对实验结果进行了关联,结果令人满意。 相似文献
6.
Purpose. The human plasma binding of cyclosporin A was studied in vitro using the technique of microdialysis. The effect of temperature on the overall binding interaction between cyclosporin A and human plasma was also investigated.
Methods. Flow-through loop-type microdialysis probes were constructed from fused silica tubing and regenerated cellulose tubing with a MWCO of 13000 daltons. Probes were perfused with phosphate buffer (0.5 µl/min) and the concentration of 3H-cyclosporin A in the well-mixed medium (plasma or buffer) was 1200 ng/ml. Relative recoveries of cyclosporin A from plasma or buffer were determined for each probe by separate experiments to measure the solute gain or loss with reference to the perfusate.
Results. Recoveries determined by loss were significantly greater than those determined by gain and in each case temperature dependent, with higher recoveries at higher temperatures. The plasma free fraction of cyclosporin A calculated from the recovery data and the perfusate to plasma concentration ratios was dependent on temperature in a log-linear fashion. Mean ± s.d. plasma free fractions expressed in percent were 33.5 ± 4.6, 17.9 ± 3.6, 6.2 ± 0.8, 3.0 ± 0.6, and 1.5 ± 0.2 at temperatures of 4, 10, 20, 30, and 37°C, respectively. Assuming that the enthalpy of binding is constant over the temperature range studied and pseudo-first order conditions exist, the binding reaction at these temperatures was spontaneous, endothermic (H = 74.0 kJ/mole), and entropically driven (S = 0.274 kJ/mole/deg).
Conclusions. These results show that the free fraction of cyclosporin A in human plasma is dependent on temperature with the fraction unbound decreasing with temperature in the range of 4 to 37°C. The thermodynamic parameters for the binding of cyclosporin A to plasma components indicate that the reaction is a spontaneous endothermic reaction that is mainly entropy driven, similar to the partitioning of lipophilic molecules from an aqueous to a hydrophobic phase. Moreover, these results show that microdialysis is a feasible method to determine the binding interactions between plasma and cyclosporin A, which indicates the method may be suitable for other difficult binding studies where the solutes have nonspecific binding to separation devices. 相似文献
7.
A nanoparticle, under biological milieu, is inclined to be combined with various biomolecules, particularly protein, generating an interfacial corona which provides a new biological identity. Herein, the binding interaction between silver nanoparticles (AgNPs) and human serum albumin (HSA) was studied with transmission electron microscopy (TEM), circular dichroism (CD), and multiple spectroscopic techniques. Due to the ground state complex formed mainly through hydrophobic interactions, the fluorescence titration method proved that intrinsic fluorescence for HSA was probably statically quenched by AgNPs. The complete thermodynamic parameters were derived, indicating that the interaction between HSA and AgNPs is an entropy-driven process. Additionally, synchronous fluorescence and CD spectrum results suggested the conformational variation it has upon binding to AgNPs and the α-helix content has HSA visibly decreased. The kinetic experiments proved the double hysteresis effect has in HSA’s binding to the AgNPs surface. Moreover, the binding has between HSA and AgNPs follows the pseudo-second-order kinetic characteristic and fits the Freundlich model for multilayer adsorption. These results facilitate the comprehension about NPs’ underlying biological effects under a physiological environment and promote the secure applications of NPs biologically and medically. 相似文献
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10.
Olga S. Volkova Abdellali Hadj-Azzem Gyorgy Remenyi Jose Emilio Lorenzo Pierre Monceau Alexander A. Sinchenko Alexander N. Vasiliev 《Materials》2022,15(24)
Terbium tritelluride, TbTe3, orders antiferromagnetically in three steps at TN1 = 6.7 K, TN2 = 5.7 K, and TN3 = 5.4 K, preceded by a correlation hump in magnetic susceptibility at T* ~8 K. Combining thermodynamic, i.e., specific heat Cp and magnetization M, and transport, i.e., resistance R, measurements we established the boundaries of two commensurate and one charge density wave modulated phases in a magnetic field oriented along principal crystallographic axes. Based on these measurements, the magnetic phase diagrams of TbTe3 at H‖a, H‖b and H‖c were constructed. 相似文献