Synthesis and <Emphasis Type="Italic">in vitro</Emphasis> evaluation of new diphenyl ether derivatives as serotonin transporter ligands

For the development of new ligands as potential imaging agents for the serotonin transporter (SERT), a series of diphenyl ether derivatives have been synthesized, characterized, and evaluated for their in vitro binding affinities to the SERT. Among the above compounds, 2-(2-((dimethylamino)methyl)-4-fluorophenoxy)-5-bromobenzenamine (15) and 2-(2-((dimethylamino)methyl)-4-fluorophenoxy)-5-iodobenzene amine (16) show high binding affinities for the SERT with K _i values of 0.28 and 0.20 nmol·L⁻¹, respectively. They can be further labeled with carbon-11, fluorine-18, iodine-123 or bromine-76, and evaluated as useful imaging agents for the SERT. Moreover, the study of the structure-activity relationship (SAR) provides some useful information for the future design of new ligands. Supported by the National Natural Science Foundation of China (Grant No. 20471011)     

Variational approaches to p-Laplacian discrete problems of Kirchhoff-type

Critical point results for Kirchhoff-type discrete boundary value problems are exploited in order to prove that a suitable class possesses at least one solution under an asymptotical behaviour of the potential of the nonlinear term at zero, and also possesses infinitely many solutions under some hypotheses on the behaviour of the potential of the nonlinear term at infinity. Some recent results are extended and improved. Some examples are presented to demonstrate the applications of our main results.     

Global test for metabolic pathway differences between conditions

In many metabolomics applications there is a need to compare metabolite levels between different conditions, e.g., case versus control. There exist many statistical methods to perform such comparisons but only few of these explicitly take into account the fact that metabolites are connected in pathways or modules. Such a priori information on pathway structure can alleviate problems in, e.g., testing on individual metabolite level. In gene-expression analysis, Goeman's global test is used to this extent to determine whether a group of genes has a different expression pattern under changed conditions. We examined if this test can be generalized to metabolomics data. The goal is to determine if the behavior of a group of metabolites, belonging to the same pathway, is significantly related to a particular outcome of interest, e.g., case/control or environmental conditions. The results show that the global test can indeed be used in such situations. This is illustrated with extensive intracellular metabolomics data from Escherichia coli and Saccharomyces cerevisiae under different environmental conditions.     

Double Solutions of Impulsive Dynamic Boundary Value Problems on a Time Scale

A double fixed-point theorem is applied to obtain the existence of at least two positive solutions of a right focal boundary value problem for a second order impulsive dynamic equation on a time scale.     

Anti-periodic solutions of higher order nonlinear difference equations: a variational approach

A 2nth order nonlinear difference equation is studied. By using a variational approach, existence results for anti-periodic solutions are obtained under various assumptions upon the nonlinearities.     

A Filippov’s Theorem, Some Existence Results and the Compactness of Solution Sets of Impulsive Fractional Order Differential Inclusions

In this paper, we first present an impulsive version of Filippov's Theorem for fractional differential inclusions of the form, $$\begin{array}{lll} \quad \qquad D^{\alpha}_{*}y(t) & \in & F(t, y(t)), \quad\; {\rm a.e.}\ t\, \in \, J{\backslash} \{t_{1}, \ldots, t_{m}\}, \ \alpha\, \in \, (0,1], \\ y(t^{+}_{k}) - y(t^{-}_{k}) & = & I_{k}(y(t^{-}_{k})), \quad k = 1, \ldots, m, \\ \qquad \qquad y(0) & = & a,\end{array}$$ where J = [0, b], ${D^{\alpha}_{*}}$ denotes the Caputo fractional derivative and F is a set-valued map. The functions I _k characterize the jump of the solutions at impulse points t _k ( ${k = 1, \ldots , m}$ ). In addition, several existence results are established, under both convexity and nonconvexity conditions on the multivalued right-hand side. The proofs rely on a nonlinear alternative of Leray-Schauder type and on Covitz and Nadler??s fixed point theorem for multivalued contractions. The compactness of solution sets is also investigated.     

Non-isothermal crystallization of PVDF/PMMA blends processed in low and high shear mixers

The morphological, thermal and non-isothermal crystallization behavior of poly(vinylidene fluoride) (PVDF) and its blends with poly(methyl methacrylate) (PMMA) processed in low (LSM) and high (HSM) shear mixers were studied by differential scanning calorimetry (DSC). The processing effect on the PVDF melt and crystallization kinetics was described and the effect of PMMA on the PVDF crystallization was also investigated. The addition of PMMA into PVDF increases of relative B phase content independent of the processing conditions. The validity of the modified Avrami and Kolmogorov–Johnson–Mehl–Avrami (KJMA) models for the non-isothermal crystallization of PVDF/PMMA blends are discussed. The KJMA method described accurately the non-isothermal crystallization behavior. The results showed a shift in the PVDF crystallization/fusion peak to lower temperatures. The activation energies for crystallization of PVDF and its blends evaluated through the isoconversional method using Friedman's approximation were higher for samples processed in the LSM. Differences in the activation energies were related to the ability of the molecular segments to crystallize when reaching the growing crystallization front, confirming that the mixing process has some effect on the interaction between the polymers. On the other hand, the isoconversional methods in combination with the KJMA equation provide better understanding of the kinetics of the crystallization process demonstrated by a strongly dependence of activation energy (Ea), relative crystalline fraction (XT), and global and local Avrami exponents (n and n (XT)).