Strominger–Yau–Zaslow Geometry,Affine Spheres and Painlevé III

We give a gauge invariant characterisation of the elliptic affine sphere equation and the closely related Tzitzéica equation as reductions of real forms of anti–self–dual Yang–Mills equations by two translations, or equivalently as a special case of the Hitchin equation. We use the Loftin–Yau–Zaslow construction to give an explicit expression for a six–real dimensional semi–flat Calabi–Yau metric in terms of a solution to the affine-sphere equation and show how a subclass of such metrics arises from 3^rd Painlevé transcendents.     

Energetics of conformational conversion between 1,1,2-trichloroethane polymorphs

Pressure-induced transformations between gauche(-), gauche(+) and transoid conformations have been evidenced by X-ray single-crystal diffraction for 1,1,2-trichloroethane, and the energies of intermolecular interactions, conformational conversion, and the latent heat have been determined.     

Numerical analysis of high Q-factor photonic-crystal VCSELs with plane-wave admittance method

The paper presents the application of a novel plane-wave admittance method (PWAM) to the three-dimensional and fully vectorial modeling of vertical-cavity surface-emitting lasers with incorporated photonic crystal. The basic mathematical details of the method are given and its convergence is verified for a sample structure. Then the simulations performed with PWAM are used to determine the optimal photonic crystal parameters for low-loss, high-Q-factor regime.     

Functional Protein Composition in Femoral Glands of Sand Lizards (Lacerta agilis)

Proteins are ubiquitous macromolecules that display a vast repertoire of chemical and enzymatic functions, making them suitable candidates for chemosignals, used in intraspecific communication. Proteins are present in the skin gland secretions of vertebrates but their identity, and especially, their functions, remain largely unknown. Many lizard species possess femoral glands, i.e., epidermal organs primarily involved in the production and secretion of chemosignals, playing a pivotal role in mate choice and intrasexual communication. The lipophilic fraction of femoral glands has been well studied in lizards. In contrast, proteins have been the focus of only a handful of investigations. Here, we identify and describe inter-individual expression patterns and the functionality of proteins present in femoral glands of male sand lizards (Lacerta agilis) by applying mass spectrometry-based proteomics. Our results show that the total number of proteins varied substantially among individuals. None of the identified femoral gland proteins could be directly linked to chemical communication in lizards, although this result hinges on protein annotation in databases in which squamate semiochemicals are poorly represented. In contrast to our expectations, the proteins consistently expressed across individuals were related to the immune system, antioxidant activity and lipid metabolism as their main functions, showing that proteins in reptilian epidermal glands may have other functions besides chemical communication. Interestingly, we found expression of the Major Histocompatibility Complex (MHC) among the multiple and diverse biological processes enriched in FGs, tentatively supporting a previous hypothesis that MHC was coopted for semiochemical function in sand lizards, specifically in mate recognition. Our study shows that mass spectrometry-based proteomics are a powerful tool for characterizing and deciphering the role of proteins secreted by skin glands in non-model vertebrates.     

Indirect spectrophotometric determination of fluoride using the ternary system: Thorium-chrome azurol S-cetyltrimethylammonium

Summary The conditions for the reactions of fluoride with the ternary Th-CAS-CTA/CP/zeph and Th-ECR-CTA complexes have been examined, and a new, sensitive and precise method based on the Th-CAS-CTA-F^– system developed for the indirect determination of fluoride. The molar absorptivity of the method is extremely high —10.0× 10⁴l·mole^–1·cm^–1 at 635 nm (in the others, frequently used, spectrophotometric methods for determining fluoride, does not exceed 2.7×10⁴, e. g. for the method with Alizarin Complexone —1.4×10⁴ and with zirconium and Eriochrome Cyanine R— 2.7×10⁴). Beer's law is obeyed up to a fluoride concentration up to 0.08g per ml. The precision and accuracy of the method were tested in analysis of tap water.

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Indirekte spektrophotometrische Bestimmung von Fluorid mit Hilfe des Systems Thorium-Chromazurol S-Cetyltrimethylammonium

Zusammenfassung Die Bedingungen für die Umsetzung von Fluorid mit den ternären Komplexen Th-CAS-CTA(CP)zeph und Th-ECR-CTA wurden geprüft und eine neue, empfindliche und genaue Methode für die indirekte Fluoridbestimmung ausgearbeitet, die auf dem System Th-CAS-CTA-F^– beruht. Dessen molare Absorptivität ist sehr groß: 10,0×10⁴l·mol^–1·cm^–1 bei 635 nm. (Bei den üblichen spektrophotometrischen Methoden zur Fluoridbestimmung ist nicht größer als 2,7×10⁴ bei der Methode mit Zr und Eriochromcyanin bzw. 1,4×10⁴ bei der Methode mit Alizarin-Komplexon). Das Beersche Gesetz gilt bis zu 0,08g Fluorid/ml. Die Genauigkeit des Verfahrens wurde mit Analysen von Leitungswasser geprüft.

     

Thiol–Anhydride Dynamic Reversible Networks

The reaction of thiols and anhydrides to form ring opened thioester/acids is shown to be highly reversible and it is accordingly employed in the fabrication of covalent adaptable networks (CANs) that possess tunable dynamic covalent chemistry. Maleic, succinic, and phthalic anhydride derivatives were used as bifunctional reactants in systems with varied stoichiometries, catalyst, and loadings. Dynamic characteristics such as temperature-dependent stress relaxation, direct reprocessing and recycling abilities of a range of thiol–anhydride elastomers, glasses, composites and photopolymers are discussed. Depending on the catalyst strength, 100 % of externally imposed stresses were relaxed in the order of minutes to 2 hours at mild temperatures (80–120 °C). Pristine properties of the original materials were recovered following up to five cycles of a hot-press reprocessing technique (1 h/100 °C).