Quark model analysis of hyperon semileptonic decays

A study of hyperon semileptonic decays has been made in various quark models and compared with the standard Cabibbo analysis which is found to be in good agreement with experiments. Results obtained in a quasirelativistic constituent quark model are in reasonable agreement with the standard Cabibbo analysis and show no sizeableSU(3) symmetry breaking effects. Results in other quark models which take into account theSU(3) symmetry breaking effects in the dominant form factors are similar to the quasirelativistic constituent quark model.     

Die Mikrogaskammermethode und die Mikrosublimation als Hilfsmittel bei der Bewertung von pflanzlichen Warenproben

Ohne Zusammenfassung     

Self–gravitating fluid flows with Gowdy symmetry near cosmological singularities

We consider self-gravitating fluids in cosmological spacetimes with Gowdy symmetry on the torus T³ and, in this class, we solve the singular initial value problem for the Einstein–Euler system of general relativity, when an initial data set is prescribed on the hypersurface of singularity. We specify initial conditions for the geometric and matter variables and identify the asymptotic behavior of these variables near the cosmological singularity. Our analysis of this class of nonlinear and singular partial differential equations exhibits a condition on the sound speed, which leads us to the notion of sub-critical, critical, and super-critical regimes. Solutions to the Einstein–Euler systems when the fluid is governed by a linear equation of state are constructed in the first two regimes, while additional difficulties arise in the latter one. All previous studies on inhomogeneous spacetimes concerned vacuum cosmological spacetimes only.     

Homogenization of thermomechanical tread-road contact for the investigation of tire rolling resistance

A homogenization framework for the stochastic average meso-scale tread-road interaction with emphasis on macro-scale rolling resistance calculations is presented in this contribution. This framework accounts for large scale, high-frequency penetration of tread rubber by the highest asperities as well as for the nonlinear thermo-viscoelastic material behavior of this tread rubber in the regime of finite strains. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Characterization of poly(2,6-diphenyl-p-phenylene oxide) films as adsorbent for microfabricated preconcentrators

This work aims at evaluating poly(2,6-diphenyl-p-phenylene oxide) (Tenax TA), in the form of thin films, as an adsorbent material for various analytical applications. The physical properties of the polymer were studied with regard to surface topography, crystal structure, and thermal stability. Films deposited from solution at different substrate temperatures were studied and compared to the granular form of the polymer. It was found that Tenax TA deposited from solution have a different topography compared to their granular counterpart. The films possess a complex phase composition that includes crystalline and amorphous phases. The films showed high thermal stability (400 °C) similar to the granular form. The adsorption performance of the polymer compared to other possible adsorbent films such as polydimethylsiloxane (PDMS) and layer-by-layer assembled gold nanoparticles (GNPs) were also investigated. Representative volatile organic compound samples were used to compare the adsorption properties of Tenax TA films to that of the granules.     

Structure, solution chemistry, antiproliferative actions and protein binding properties of non-conventional platinum(II) compounds with sulfur and phosphorus donors

Twelve Pt(II) complexes with cis-PtP(2)S(2) pharmacophores (where P(2) refers to two monodentate or one bidentate phosphane ligand and S(2) is a dithiolato ligand) were prepared, characterized and evaluated as potential antiproliferative agents. The various compounds were first studied from the structural point of view; afterward, their solubility properties as well as their solution behaviour were analyzed in detail. Antiproliferative properties were specifically evaluated against A2780 human ovarian carcinoma cells, either resistant or sensitive to cisplatin. For comparison purposes similar studies were carried out on four parent cis-dichloro bisphosphane Pt(II)complexes. On the whole, the cis-PtP(2)S(2) compounds displayed significant antiproliferative properties while the cis-PtP(2)Cl(2) (cis-dichloro bisphosphane Pt(II)) compounds revealed quite poor biological performances. To gain further insight into the molecular mechanisms of these bisphosphane Pt(II) compounds, the reactions of selected complexes against the model protein cytochrome c were investigated by ESI-MS and their adduct formation explored. A relevant reactivity with cyt c was obtained only for cis-PtP(2)Cl(2) compounds, whereas cis-PtP(2)S(2) compounds turned out to be nearly unreactive. The obtained results are interpreted and discussed in the frame of the current knowledge of anticancer platinum compounds and their structure-activity-relationships. The observation of appreciable antiproliferative effects for the relatively inert cis-PtP(2)S(2) compounds strongly suggests that these compounds will undergo specific activation within the cellular environment.     

The reals as full and balanced biframe

This paper is the first part of a two-part investigation. It introduces full and balanced biframes which capture useful properties of the reals viewed as a biframe (or bitopological space). The subsequent paper will apply these concepts to the study of completions of quasi-nearness biframes.We start with the smallest dense quotient for biframes. Next we discuss the reals as a biframe and introduce the key ideas of balanced, full and stable biframes. The crucial tool here is the frame pseudocomplement. We include a discussion of the relations between the newly introduced ideas and regularity. Order topology biframes are all regular, normal and balanced but not necessarily full. We consider the plane and various examples related to zero-dimensionality. We provide methods of transferring fullness and balancedness from domain to codomain and conversely under various kinds of maps.Of particular importance to our later study of completions is the idea of a biframe map whose right adjoint preserves the first and second parts of the biframe. We give a result providing sufficient conditions for a map to have a part-preserving right adjoint. We present an example of a dense onto map (which is in fact a compactification) between normal, regular biframes whose right adjoint is not part-preserving. The paper concludes with internal properties of full and balanced biframes showing the particularly close connection between the first and second parts and ends with a final visit to the biframe of reals.     

A 'microfluidic pinball' for on-chip generation of Layer-by-Layer polyelectrolyte microcapsules

Inspired by the game of "pinball" where rolling metal balls are guided by obstacles, here we describe a novel microfluidic technique which utilizes micropillars in a flow channel to continuously generate, encapsulate and guide Layer-by-Layer (LbL) polyelectrolyte microcapsules. Droplet-based microfluidic techniques were exploited to generate oil droplets which were smoothly guided along a row of micropillars to repeatedly travel through three parallel laminar streams consisting of two polymers and a washing solution. Devices were prototyped in PDMS and generated highly monodisperse and stable 45±2 μm sized polyelectrolyte microcapsules. A total of six layers of hydrogen bonded polyelectrolytes (3 bi-layers) were adsorbed on each droplet within <3 minutes and a fluorescent intensity measurement confirmed polymer film deposition. AFM analysis revealed the thickness of each polymer layer to be approx. 2.8 nm. Our design approach not only provides a faster and more efficient alternative to conventional LbL deposition techniques, but also achieves the highest number of polyelectrolyte multilayers (PEMs) reported thus far using microfluidics. Additionally, with our design, a larger number of PEMs can be deposited without adding any extra operational or interfacial complexities (e.g. syringe pumps) which are a necessity in most other designs. Based on the aforementioned advantages of our device, it may be developed into a great tool for drug encapsulation, or to create capsules for biosensing where deposition of thin nanofilms with controlled interfacial properties is highly required.