Thermodynamical consistency of the dual-phase-lag heat conduction equation

Dual-phase-lag equation for heat conduction is analyzed from the point of view of non-equilibrium thermodynamics. Its first-order Taylor series expansion is consistent with the second law as long as the two relaxation times are not negative.     

Limiting the Number of Potential Binding Modes by Introducing Symmetry into Ligands: Structure‐Based Design of Inhibitors for Trypsin‐Like Serine Proteases

In the absence of X‐ray data, the exploration of compound binding modes continues to be a challenging task. For structure‐based design, specific features of active sites in different targets play a major role in rationalizing ligand binding characteristics. For example, dibasic compounds have been reported as potent inhibitors of various trypsin‐like serine proteases, the active sites of which contain several binding pockets that can be targeted by cationic moieties. This results in several possible orientations within the active site, complicating the binding mode prediction of such compounds by docking tools. Therefore, we introduced symmetry in bi‐ and tribasic compounds to reduce conformational space in docking calculations and to simplify binding mode selection by limiting the number of possible pocket occupations. Asymmetric bisbenzamidines were used as starting points for a multistage and structure‐guided optimization. A series of 24 final compounds with either two or three benzamidine substructures was ultimately synthesized and evaluated as inhibitors of five serine proteases, leading to potent symmetric inhibitors for the pharmaceutical drug targets matriptase, matriptase‐2, thrombin and factor Xa. This study underlines the relevance of ligand symmetry for chemical biology.     

Connected signed graphs of fixed order,size, and number of negative edges with maximal index

In this paper we focus on connected signed graphs of fixed number of vertices, positive edges and negative edges that maximize the largest eigenvalue (also called the index) of their adjacency matrix. In the first step we determine these signed graphs in the set of signed generalized theta graphs. Concerning the general case, we use the eigenvector techniques for getting some structural properties of resulting signed graphs. In particular, we prove that positive edges induce nested split subgraphs, while negative edges induce double nested signed subgraphs. We observe that our concept can be applied when considering balancedness of signed graphs (the property that is extensively studied in both mathematical and non-mathematical context).     

Magnetic Properties of Amorphous and Nanocrystalline Fe-Zr-B-Al Alloys

We have investigated the influence of aluminium substitution for iron on the magnetic properties of amorphous and nanocrystalline Fe_88-x Zr₇B₅Al _x alloys (x = 0, 1, 3, 5, 7 and 9 at.%). Thermomagnetic curves show an increase of Curie and crystallization temperature of amorphous phase with the increase of the content of aluminium in the alloy. The increase of aluminium content up to 3 at.% Al does not cause the decrease of a saturation magnetization in the as-quenched sample. In addition, magnetostriction of the annealed alloys has been studied. Also, the increase of aluminium content in the alloy causes an increase of the magnetostriction constant.     

Poly(ethylene glycol)-supported tetrahydroxyphenyl porphyrin: a convenient,recyclable catalyst for photooxidation reactions

[reaction: see text] A new poly(ethylene glycol)-supported porphyrin has been prepared and its ability as a promoter in photooxidation reactions has been studied. The PEG-supported catalyst exhibits high activity, comparable to that of a nonanchored sensitizer, and it is easily removable by filtration from the reaction mixture. The polymer-bound porphyrin has been recycled up to six times with no loss of chemical and stereochemical efficiency.     

Total synthesis and proof of structure of mycothiol bimane

Mycothiol is a low-molecular weight thiol produced by actinomycetes that serves to protect these organisms from oxidative stress and alkylating agents. We report the total synthesis of mycothiol bimane (1) which is a commonly isolated derivative of mycothiol. The synthesis confirms the original structure assignment and unambiguously establishes the absolute stereochemistry of mycothiol to be 1-d-myo-inosityl 2-deoxy-2-(N-acetamido-l-cysteinamido)-alpha-d-glucopyranoside.     

Angular dispersion of femtosecond pulses in a Gaussian beam

The angular dispersion of spatially Gaussian laser pulses, unlike for plane waves, changes with the distance between the disperser and the observer and between the beam waist and the disperser. The formula that is derived is experimentally verified by use of a high-precision measurement technique. Because the angular dispersion of a Gaussian beam is substantially different from that of a plane wave after the same disperser, the phenomenon may be of special interest for short-pulsed laser systems, for which alignment of the stretcher-compressor system for zero residual angular dispersion is essential.     

Determination of biogenic amines by capillary electrophoresis

A method for determining biogenic amines in food using micellar electrokinetic capillary chromatography has been developed. Derivatization of the amines was performed with AccQ (6-aminoquinolyl-N-hydroxysuccinimidyl carbamate; Waters, Milford, MA, USA) reagent. The influence of buffer composition on the separation (including pH, SDS concentration and various additives) was investigated. The separation of seven biogenic amines (histamine, tyramine, tryptamine, spermine, spermidine, cadaverine and putrescine) could be achieved within 25-30 min with good repeatability. The biogenic amine profiles in three different food samples (wine, salami and chive) were determined and quantitated.     

Volatilization of ultramicro amounts of Mo and Tc from AgCl melt in vacuum and their separation by thermochromatographic method

Volatilization and thermochromatographic separation of ultramicro amounts of Mo and Tc from AgCl melt irradiated with 6 60 MeV protons have been studied in vacuum at 600 °C. It has been found that in quartz apparatus Tc, and while using graphite, Mo can be separated from the other leaving elements. On the basis of the experimental results an ion source can be contructed for the on-line nuclear spectroscopic studies of Mo and Tc isotopes.