Two new integrable couplings of the soliton hierarchies with self-consistent sources

A kind of integrable coupling of soliton equations hierarchy with self-consistent sources associated with sl(4) has been presented (Yu F J and Li L 2009 Appl. Math. Comput. 207 171; Yu F J 2008 Phys. Lett. A 372 6613). Based on this method, we construct two integrable couplings of the soliton hierarchy with self-consistent sources by using the loop algebra sl(4). In this paper, we also point out that there are some errors in these references and we have corrected these errors and set up new formula. The method can be generalized to other soliton hierarchy with self-consistent sources.     

Lie Algebras for Constructing Nonlinear Integrable Couplings

Two new explicit Lie algebras are introduced for which the nonlinear integrable couplings of the Giachetti-Johnson (GJ) hierarchy and the Yang hierarchy are obtained, respectively. By employing the variational identity their Hamiltonian structures are also generated. The approach presented in the paper can also
provide nonlinear integrable couplings of other soliton hierarchies of evolution equations.     

Specific Heat of a Two-Layer Magnetic Superlattice

The specific heats of both a two-layer ferromagnetic superlattice and atwo-layer ferrimagnetic one are studied. It is found that the spin quantumnumbers, the interlayer and intralayer exchange couplings, the anisotropy,the applied magnetic field, and the temperature all affect the specificheat of these superlattices. For both the ferromagnetic and ferrimagneticsuperlattices, the specific heat decreases with increasing the spin quantumnumber, the absolute value of interlayer exchange coupling, intralayerexchange coupling, and anisotropy, while it increases with increasingtemperature at low temperatures. When an applied magnetic field is enhanced, the specific heat decreases in the two-layer ferromagnetic superlattice, while it is almost unchanged in the two-layer ferrimagnetic superlattice at low field range at low temperatures.     

New Matrix Loop Algebra and Its Application

A new matrix Lie algebra and its corresponding Loop algebra are constructed firstly, as its application, the multi-component TC equation hierarchy is obtained, then by use of trace identity the Hamiltonian structure of the above system is presented. Finally, the integrable couplings of the obtained system is worked out by the expanding matrix Loop algebra.     

残留偶极耦合及其在蛋白质结构研究中的应用

近年来溶液中残留偶极耦合常数被用来获取生物大分子化学键之间相对取向等长程构象约束条件,用于计算或优化蛋白质及其复合物的三维空间结构. 介绍了用异核多维NMR技术测量残留偶极耦合常数的方法,及其在蛋白质结构计算中的一些应用：优化蛋白质溶液结构,评价蛋白质结构质量,确定蛋白质结构域取向,获取有关配体的构象和取向的信息,在缺乏NOE数据时构建蛋白质结构等.      

Strengths and weaknesses of in-tube solid-phase microextraction: A scoping review

In-tube solid-phase microextraction (in-tube SPME or IT-SPME) is a sample preparation technique which has demonstrated over time its ability to couple with liquid chromatography (LC), as well as its advantages as a miniaturized technique. However, the in-tube SPME perspectives in the forthcoming years depend on solutions that can be brought to the environmental, industrial, food and biomedical analysis. The purpose of this scoping review is to examine the strengths and weaknesses of this technique during the period 2009 to 2015 in order to identify research gaps that should be addressed in the future, as well as the tendencies that are meant to strengthen the technique.     

Model Calculations of Radiation-Induced Damage in Thymine Derivatives

When the thymine base is oxidized, the resulting cation may deprotonate reversibly at N3, or irreversibly at >C5-CH₃. In all thymine derivatives studied so far in the solid state, there is always a significant concentration of a radical formed by net H-abstraction from the >C5-CH₃. DFT calculations on this allyl-like radical are in good agreement with the experimental results for both the isotropic and anisotropic hyperfine couplings. There is a tendency for the thymine cation to deprotonate at N3 in solution. Calculations on the N3 deprotonated thymine cation yield two structures, one planar radical with an unusually large N1-C2 bond length, and one nonplanar radical with the N3 more than 25° out of the molecular plane. Calculations show that the structure with the lowest energy is the allyl-like radical.     

Biphenomycin B and Derivatives: Total Synthesis and Translation Inhibition

A full account on the synthesis of the antibiotic natural product biphenomycin B and several derivatives is reported, which employs a Suzuki coupling reaction of a free carboxylic acid and macrolactam formation as key transformations. Liberal exchange of the central amino acid was demonstrated. This procedure gave derivatives to study the influence of the polar side chain of the central amino acids on translation inhibition.