Reduction of Capsorubin and Cryptocapsin

(6′S)‐ and (6′R)‐‘Capsorubol‐6‐one' (=(3S,3′S,5R,5′R,6′S)‐ and (3S,3′S,5R,5′R,6′R)‐3,3′,6′‐trihydroxy‐κ,κ‐caroten‐6‐one; 8 and 9 , resp.), (6S,6′R)‐ and (6R,6′R)‐capsorubol (=3S,3′S,5R,5′R,6S,6′R)‐ and (3S,3′S,5R,5′R,6R,6′R)‐κ,κ‐carotene‐3,3′,6,6′‐tetrol; 11 and 12 , resp.) and (6′S)‐ and (6′R)‐cryptocapsol (=(3′S,5′R,6′S)‐ and (3′S,5′R,6′R)‐β,κ‐carotene‐3′,6′‐diol; 5 and 6 , resp.) were prepared in crystalline from by the reduction of capsorubin (=(3S,3′S,5R,5′R)‐3,3′‐dihydroxy‐κ,κ‐carotene‐6,6′‐dione; 7 ) and cryptocapsin (=(3′S,5′R)‐3′‐hydroxy‐β,κ‐caroten‐6′‐one; 4 ) and characterized by their UV/VIS, CD, ¹H‐NMR, and mass spectra.     

Surface tension and mechanical properties in polyolefin composites

Polyolefin composites were prepared with CaCO₃ fillers of different specific surface area. The fillers were surface treated with stearic acid between 0 and 100% surface coverage. As an effect of the treatment, surface tension of the fillers and also polymer/filler interaction decreased. The relation between interfacial interaction and mechanical properties of the composites was analysed by the equation developed earlier to describe the composition dependence of the tensile yield stress. The characteristics of the interphase were calculated, its yield stress decreases and thickness increases with increasing surface coverage. Reversible work of adhesion can be successfully related to the tensile yield stress, but a more complicated correlation exists between the thickness of the interphase and the strength of the interaction than assumed earlier. Other mechanical properties also change with the surface treatment; modulus and strength decrease and extensibility increases with decreasing polymer/filler interaction.     

Topical Dosage Formulation of Lyophilized Philadelphus coronarius L. Leaf and Flower: Antimicrobial,Antioxidant and Anti-Inflammatory Assessment of the Plant

Philadelphus coronarius is a versatile plant and its use in folk medicine has a long tradition; however, scientifically, the medical utilization of the herb is a less explored research field. The aim of our study was to identify and determine the quantity of the bioactive compounds of both the leaf and the flower and prepare a lyophilized product of them, from which medical ointments were formulated, since the topical application of P. coronarius has also not been studied. In vitro drug release, texture analysis and biocompatibility experiments were carried out, as well as the investigation of microbiological, antioxidant and anti-inflammatory properties. According to our results the composition and the selected excipients of the ointments have a great impact on the drug release, texture and bioavailability of the preparation. During the microbiological testing, the P. coronarius leaf was effective against Escherichia coli and Staphylococcus aureus, but it did not significantly decrease IL-4 production when it was tested on HaCaT cells. P. coronarius is a promising herb, and its topical application in antimicrobial therapy can be a useful addition to modern medical therapy.     

Investigation of the carrier function of polypeptides. Synthesis,conformation and cytotoxicity of oxazolone conjugates of poly(Lys) and poly[Lys-(DL-ALAm)]

A new group of synthetic macromolecular conjugates was synthesised in which poly(Lys) or a branched polypeptide poly[Lys-(DL-Ala_m)] (m≅3) were used as carrier and 4-(ethoxymethylene)-2–phenyl–5 (4H)-oxazolone as hapten. These conjugates were characterized by amino acid analysis, identification of terminal residues of the side chain, sedimentation analysis. The conformation of conjugates and of carrier polypeptides were analyzed by circular dichroism spectroscopy in water solutions at various pH and ionic strengths. These data indicated a marked dependence of the conformation of the conjugate on the structure of carrier and on the number of the side chain terminal haptens (phOx). In vitro cytotoxicity of these polymers was also investigated using two different assays, by measuring the viability of isolated rat liver cells and the effect on growth of HeLa cells. Toxicity of polypeptides could be diminished by conjugates containing a higher amount of oxazolone. These conjugates with defined conformation and toxicological properties are considered suitable to analyse the carrier function of branched polypeptides, particularly the interaction with the immunological network.     

Influence of heat transfer on the dynamic response of a spherical gas/vapour bubble

The standard approach to analyse the bubble motion is the well known Rayleigh–Plesset equation. When applying the toolbox of nonlinear dynamical systems to this problem several aspects of physical modelling are usually sacrificed. Particularly in vapour bubbles the heat transfer in the liquid domain has a significant effect on the bubble motion; therefore the nonlinear energy equation coupled with the Rayleigh–Plesset equation must be solved. The main aim of this paper is to find an efficient numerical method to transform the energy equation into an ODE system, which, after coupling with the Rayleigh–Plesset equation can be analysed with the help of bifurcation theory. Due to the strong nonlinearity and violent bubble motions the computational effort can be high, thus it is essential to reduce the size of the problem as much as possible. In the first part of the paper finite difference, Galerkin and spectral collocation methods are examined and compared in terms of efficiency. In the second part free and forced oscillations are analysed with an emphasis on the influence of heat transfer. In the case of forced oscillations the unstable branches of the amplification diagrams are also computed.     

Solution pH: A Selectivity Switch in Aqueous Organometallic Catalysis—Hydrogenation of Unsaturated Aldehydes Catalyzed by Sulfonatophenylphosphane–Ru Complexes

The equilibribrium distribution of water-soluble ruthenium hydrides [HRuCl(tppms)₃] and [H₂Ru(tppms)₄] (tppms = (3-sulfonatophenyl)diphenylphosphane) in the reaction with H₂ is governed by the pH value. As a consequence, the selectivity in the hydrogenation of cinnamaldehyde for reaction at C=C or C=O can be completely inverted by changing the pH value (see drawing below).     

Deuteron N.M.R. relaxation studies of phospholipid membranes

Abstract

Bilayers of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC), specifically deuteriated at various positions of the sn-2-chain, have been studied by N.M.R. relaxation methods. Analysis of the experiments, employing a density matrix treatment based on the stochastic Liouville equation, provides new information about the dynamic organization of the different membrane phases (liquid-crystalline, intermediate and gel phases). The complex molecular dynamics are characterized by a super-position of inter- and intramolecular motions, comprising overall reorientation of phospholipid molecules and trans-gauche isomerization of individual chain segments. In addition, there is evidence for two-site rotational jumps of the sn-2-chains in the plane of the membrane. The results clearly demonstrate the particular advantage of N.M.R. relaxation studies in characterizing complex chemical and biological systems.     

From Aggregation to Chaperoning: Pressure Effect on Intermolecular Interactions of Proteins

The effect of pressure on the protein aggregation is shown in this paper. Deposition of insoluble protein aggregates is one of the key factors in the conformational diseases. Pressure counteracts the formation of intermolecular g -structure. Already slight pressurization to typically 2-3 kbar can destabilize aggregates of apo-horseradish peroxidase. On the other hand, the chaperone proteins, which prevent aggregation of damaged proteins exist in big oligomers. We show that pressure treatment of these aggregates changes the chaperone activity.     

α-Haloalkyl Haloformates and Related Compounds. II. Synthesis of Dichloromethyl Carbonates and Their Transformation to Carbamates

Dichloromethyl carbonates, easily available upon treatment alcohols with dichloromethyl chloroformate, react with various amines to give carbamates in high yield under mild conditions. Extension of the reaction for the synthesis of oxazolones from 2-aminoalcohols is also demostrated.