Probing quantum-vacuum geometrical effects with cold atoms

The lateral Casimir-Polder force between an atom and a corrugated surface should allow one to study experimentally nontrivial geometrical effects in the electromagnetic quantum vacuum. Here, we derive the theoretical expression of this force in the scattering approach. We show that large corrections to the "proximity force approximation" could be measured using present-day technology with a Bose-Einstein condensate used as a vacuum field sensor.     

Lipophilicity and bio‐mimetic properties determination of phytoestrogens using ultra‐high‐performance liquid chromatography

This paper presents lipophilicity and bio‐mimetic property determination of 15 phytoestrogens, namely biochanin A, daidzein, formononetin, genistein, genistein‐4,7‐dimethylether, prunetin, 3,4,7‐trihydroxyisoflavon, 4,6,7‐trihydroxyisoflavon, 4,6,7‐trimethoxyisoflavon, daidzin, genistin, ononin, sissotrin, coumestrol and coumestrol dimethylether. High‐performance liquid chromatography with fast gradient elution and Caco‐2 cell line were used to determine the physicochemical properties of selected phytoestrogens. Lipophilicity was determined on octadecyl‐sylane stationary phase using pH 2.0 and pH 7.4 buffers. Immobilized artificial membrane chromatography was used for prediction of interaction with biological membranes. Protein binding was measured on human serum albumin and α‐1‐acid‐glycoprotein (AGP) stationary phases. Caco‐2 assay was used as a gold standard for assessing in vitro permeability. The obtained results differentiate phytoestrogens according to their structure where aglycones show significantly higher lipophilicity, immobilized artificial membrane partitioning, AGP binding and Caco‐2 permeability compared with glucosides. However, human serum albumin binding was very high for all investigated compounds. Furthermore, a good correlation between experimentally obtained chromatographic parameters and in silico prediction was obtained for lipophilicity and human serum albumin binding, while the somewhat greater difference was obtained for AGP binding and Caco‐2 permeability.     

Unraveling the dynamics of the C(3P,1D) + C2H2 reactions by the crossed molecular beam scattering technique

A detailed investigation of the dynamics of the reactions of ground- and excited-state carbon atoms, C(3P) and C(1D), with acetylene is reported over a wide collision energy range (3.6-49.1 kJ mol-1) using the crossed molecular beam (CMB) scattering technique with electron ionization mass spectrometric detection and time-of-flight (TOF) analysis. We have exploited the capability of (a) generating continuous intense supersonic beams of C(3P, 1D), (b) crossing the two reactant beams at different intersection angles (45, 90, and 135 degrees ) to attain a wide range of collision energies, and (c) tuning the energy of the ionizing electrons to low values (soft ionization) to suppress interferences from dissociative ionization processes. From angular and TOF distribution measurements of products at m/z=37 and 36, the primary reaction products of the C(3P) and C(1D) reactions with C2H2 have been identified to be cyclic (c)-C3H + H, linear (l)-C3H + H, and C3 + H2. From the data analysis, product angular and translational energy distributions in the center-of-mass (CM) system for both the linear and cyclic C3H isomers as well as the C3 product from C(3P) and for l/c-C3H and C3 from C(1D) have been derived as a function of collision energy from 3.6 to 49.1 kJ mol-1. The cyclic/linear C3H ratio and the C3/(C3 + c/l-C3H) branching ratios for the C(3P) reaction have been determined as a function of collision energy. The present findings have been compared with those from previous CMB studies using pulsed beams; here, a marked contrast is noted in the CM angular distributions for both C3H- and C3-forming channels from C(3P) and their trend with collision energy. Consequently, the interpretation of the reaction dynamics derived in the present work contradicts that previously proposed from the pulsed CMB studies. The results have been discussed in the light of the available theoretical information on the relevant triplet and singlet C3H2 ab initio potential energy surfaces (PESs). In particular, the branching ratios for the C(3P) + C2H2 reaction have been compared with the available theoretical predictions (approximate quantum scattering calculations and quasiclassical trajectory calculations on ab initio triplet PESs and, very recent, statistical calculations on ab initio triplet PESs as well as on ab initio triplet/singlet PESs including nonadiabatic effects, that is, intersystem crossing). While the experimental branching ratios have been corroborated by the statistical predictions, strong disagreement has been found with the results of the dynamical calculations. The astrophysical implications of the present results have been noted.     

Synthesis and in vitro biological properties of novel cationic derivatives of amphotericin B

Novel cationic amphotericin B derivatives as highly potent antifungal agents are reported. These semi-synthetic derivatives of amphotericin B were elaborated through a series of modifications both on the nitrogen atom of the mycosamine and on the C-16 carboxylic acid moiety. The antifungal activity of the new conjugates was tested against Saccharomyces cerevisiae and also against nine different strains of Candida albicans and Candida glabrata, including an amphotericin resistant strain. High potency was observed in the case of polyamine derivatives bearing two 3-aminopropyl chains on the mycosamine. The evaluation of the biological properties also included the determination of the hemolytic activity of the compounds by measuring the EH50 values.     

Synthesis of a new seleninic acid anhydride and mechanistic studies into its glutathione peroxidase activity

Starting from low toxic salicyloylglycine, a new seleninic acid anhydride 7 that lacks SeN or SeO non-bonded interactions was synthesized. This compound exhibits a fourfold higher glutathione peroxidase-like (GPx-like) activity than ebselen and inhibits plant and mammalian 12/15-lipoxygenases at lower micromolar concentrations. Because of these pharmacological properties, 7 may constitute a new lead compound for the development of anti-inflammatory low-molecular-weight seleno-organic compounds. Analyzing the redox products of 7 with glutathione (GSH) and tBuOOH, we identified three potential catalytic cycles (A, B, C) of GPx-like activity that are interconnected by key metabolites. To study the relative contribution of these cycles to the catalytic activity, we prepared selected reaction intermediates and found that the activity of seleninic acid anhydride 7 and of the corresponding diselenide 11 and selenol 14 compounds were in the same range. In contrast, the GPx-like activity of monoselenide 9 was more than one order of magnitude lower. These data suggested that cycles A and B may constitute the major routes of GPx-like activity of 7, whereas cycle C may not significantly contribute to catalysis.     

Human reaction to vibrations from blasting activity – Norwegian exposure–effect relationships

Rock blasting may cause disturbances, fear, and annoyance in residential and community areas affected by such activities. These community reactions can be quite strong, even when the blasting activities and the resulting vibrations are unlikely to cause physical damage to building foundations or buildings. A socio-vibrational survey was undertaken to assess residential reactions to blasting activities. Vibration velocities were obtained for 520 respondent dwellings located in seven study areas, and compared to the residents’ assessments of environment quality. Even at low vibration values, many people report annoyance. Exposure–effect relationships with acceptable statistical error bands were obtained. The level of annoyance from long-term blasting activities (quarry blasting) was not higher than from finite periods of more intense blasting activities (road and rail tunnels). Providing information in advance of the blasting activities, can reduce community reactions. Self-reported sensitivity to vibrations was associated with significantly increased annoyance. Sensitivity to vibrations was uncorrelated with exposure to vibrations. Sensitivity to noise and sensitivity to vibration were moderately correlated.     

DMT-MM mediated functionalisation of the non-reducing end of glycosaminoglycans

Efficient functionalisation of the non-reducing end of uronic acid derivatives and glycosaminoglycan-derived disaccharides using peptide coupling has been achieved, mediated by the water-soluble agent DMT-MM.     

Simulation of flux during electro-membrane extraction based on the Nernst-Planck equation

The present work has for the first time described and verified a theoretical model of the analytical extraction process electro-membrane extraction (EME), where target analytes are extracted from an aqueous sample, through a thin layer of 2-nitrophenyl octylether immobilized as a supported liquid membrane (SLM) in the pores in the wall of a porous hollow fibre, and into an acceptor solution present inside the lumen of the hollow fibre by the application of an electrical potential difference. The mathematical model was based on the Nernst-Planck equation, and described the flux over the SLM. The model demonstrated that the magnitude of the electrical potential difference, the ion balance of the system, and the absolute temperature influenced the flux of analyte across the SLM. These conclusions were verified by experimental data with five basic drugs. The flux was strongly dependent of the potential difference over the SLM, and increased potential difference resulted in an increase in the flux. The ion balance, defined as the sum of ions in the donor solution divided by the sum of ions in the acceptor solution, was shown to influence the flux, and high ionic concentration in the acceptor solution relative to the sample solution was advantageous for high flux. Different temperatures also led to changes in the flux in the EME system.