Potential antidepressants. Synthesis of 6,11-dihydrodibenzo[b,e]thiepin-11-yl 4-(dimethylamino-methyl)phenyl ketone and of some related compounds

Reactions of dibenzo[b,e]thiepin-11(6H)-one (4) with 2-, 3- and 4-(dimethylaminomethyl)phenylmagnesium bromide afforded the tertiary alcohols 5a,b,c. The aldehydes 7 and 8 gave similarly the secondary alcohols 9a,b,c and 10c . Numerous attempts to prepare the corresponding ketones, especially by oxidation of 9a,b,c and 10c were unsuccessful. Only the oxidation of 9c with tetrabutylammonium chromate in chloroform afforded the desired ketone 16 . Its formation was accompanied by an important side reaction consisting in a cleavage of the “retro-ene-reaction” type leading to compound 11 and the aldehyde 13c which reacted with the chloroform present to give the alcohol 17 . Compounds 5a,b,c, 9a,b,c and 16 were tested as potential antidepressants but with the exception of some effects in the test of potentiation of yohimbine toxicity in mice, they proved inactive in this line.     

Urysohn universal space, its development and Hausdorff's approach

Three approaches to a direct construction of Urysohn universal space are compared, namely those of Urysohn, Hausdorff and Katětov. More details are devoted to the unpublished Hausdorff's approach that is shown to work in a more general situation, too.     

Rough surface scattering simulations using graphics cards

In this article we present results of rough surface scattering calculations using a graphical processing unit implementation of the Finite Difference in Time Domain algorithm. Numerical results are compared to real measurements and computational performance is compared to computer processor implementation of the same algorithm. As a basis for computations, atomic force microscope measurements of surface morphology are used. It is shown that the graphical processing unit capabilities can be used to speedup presented computationally demanding algorithms without loss of precision.     

Bottlebrush‐shaped copolymers with cellulose diacetate backbone by a combination of ring opening polymerization and ATRP

Graft copolymers with cellulose diacetate (CDA) backbone and both the poly(ε‐caprolactone) and polystyrene, or poly(butyl acrylate) or PMMA grafts were prepared by two‐step process. First, ε‐caprolactone (CL) was polymerized by ring‐opening polymerization (ROP) initiated with CDA, partly funcionalized with 2‐bromo‐isobutyryl groups (degree of functionalization was 0.5). The p(CDA‐g‐CL) copolymers were used in the second step as polyfunctional macroinitiators of ATRP of the vinyl monomer, giving densely grafted copolymers with polyester and PSt, or PBuA, or PMMA grafts. The prepared copolymers were characterized by SEC, some of them also by FTIR spectroscopy and atomic force microscopy (AFM). © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 564–573, 2008     

Mazur intersection property for Asplund spaces

The main result of the present note states that it is consistent with the ZFC axioms of set theory (relying on Martin's Maximum MM axiom), that every Asplund space of density character ω₁ has a renorming with the Mazur intersection property. Combined with the previous result of Jiménez and Moreno (based upon the work of Kunen under the continuum hypothesis) we obtain that the MIP renormability of Asplund spaces of density ω₁ is undecidable in ZFC.     

Sorptivity approximations

Approximate expressions of sorptivity have been tested against the Philip's numerical solution for porous materials with a wide range of parameters used in an exponential function of the water diffusivityD versus water content. The Philip-Knight approximation offers the best result when the flux ratio is approximated by the function derived for a constant value ofD.     

Crown reductions for the Minimum Weighted Vertex Cover problem

The paper studies crown reductions for the Minimum Weighted Vertex Cover problem introduced recently in the unweighted case by Fellows et al. [Blow-Ups, Win/Win's and crown rules: some new directions in FPT, in: Proceedings of the 29th International Workshop on Graph Theoretic Concepts in Computer Science (WG’03), Lecture notes in computer science, vol. 2880, 2003, pp. 1-12, Kernelization algorithms for the vertex cover problem: theory and experiments, in: Proceedings of the Workshop on Algorithm Engineering and Experiments (ALENEX), New Orleans, Louisiana, January 2004, pp. 62-69]. We describe in detail a close relation of crown reductions to Nemhauser and Trotter reductions that are based on the linear programming relaxation of the problem. We introduce and study the so-called strong crown reductions, suitable for finding (or counting) all minimum vertex covers, or finding a minimum vertex cover under some additional constraints. It is described how crown decompositions and strong crown decompositions suitable for such problems can be computed in polynomial time. For weighted König-Egerváry graphs (G,w) we observe that the set of vertices belonging to all minimum vertex covers, and the set of vertices belonging to no minimum vertex covers, can be efficiently computed.Further, for some specific classes of graphs, simple algorithms for the MIN-VC problem with a constant approximation factor r<2 are provided. On the other hand, we conclude that for the regular graphs, or for the Hamiltonian connected graphs, the problem is as hard to approximate as for general graphs.It is demonstrated how the results about strong crown reductions can be used to achieve a linear size problem kernel for some related vertex cover problems.     

Small camera as a handheld colorimetric tool in the analytical chemistry

Recently, there is an effort to introduce new types of analytical procedures and handheld assays to provide simple and reliable equipment for the field and household analyses. Development of diagnostic tools for self-diagnosis is another challenge in analytical chemistry. Digital cameras are widely available and cheap, hence they could be the sensor platform for construction of analytical and diagnostic methods. In general, good availability of cameras integrated into smartphones can be easily converted into an analytical tool. This review relates to the use of digital camera in analytical chemistry and there are introduced the facts how digital data can be processed and what the limits of digital photography are. Recent papers in this issue and discussion of development in camera based assays is also provided here.     

Direct modeling of flow of FENE fluids

Direct simulations of macromolecular fluids are carried out for flows between parallel plates and in expanding and contracting channels. The macromolecules are modeled as FENE dumbbells with soft disks or Lennard-Jones dumbbell-dumbbell interactions. The results are presented in terms of profiles and contour plots of velocity, pressure, temperature, density, and flow fields. In addition the data for potential energy, shear stress, and the normal components of the stress tensor are collected. In general, an excellent agreement is found between the simulated profiles and the well-known flow structures, such as flow separation and formation of viscous eddies, indicating that micro-hydrodynamics is a viable tool in linking macroscopic phenomena with the underlying physical mechanisms. The simulations are performed in the Newtonian regime, for medium-size systems comprising up to 3888 dumbbells. This number is sufficiently large to control boundary and particle number effects. The flow is induced by gravity. The traditional stochastic (thermal) and periodic boundary conditions are employed. Also, diffusive boundary conditions, which could include a stagnant fluid layer and repulsive potential walls, are developed. The scaling problems, which are related to the application of a large external force in a microscopic system (of the size of the order 100 Å), result in extreme pressure and temperature gradients. In addition, the viscosity and thermal conductivity coefficients obtained from velocity and temperature profiles of the channel flow are presented. These results are confirmed independently from modeling of Couette flow by the SLLOD equations of motion and from the Evans algorithm for thermal conductivity.