Inductive charge dispersal in the solvolysis of 2-exo- and 2-endo-norbornyl toluenesulfonates.

The effect of substituents at C4, 5, 6 and 7 on solvolysis rates and products of 2-exo- and 2-endo-norbornyl tosylates confirms that differential carbon participation is responsible for varying exo/endo rate and product ratios.     

Crystal and molecular structure of phenylbenzyl-1-(2,2,3-trimethylcyclopropyl)phosphine oxide

The title compound crystallizes in the orthorhombic space groupPna2₁, witha=15.576(2),b=19.134(3),c=5.693(1) Å andz=4. The structure was solved by direct methods, and refined to a finalR value of 0.059. This study confirms both the structure and stereochemistry of the title compound.     

Hidden symmetry and correlated states of electrons and holes in quantum dots

We describe hidden symmetry and its application to the construction of exact correlated states of electrons and holes in quantum dots. The hidden symmetry is related to degenerate single particle energy shells and symmetric interactions. Both can be engineered in a quantum dot. We focus on hidden symmetry involving spin singlet pairing of electrons and spin singlet pairing of holes. Detailed calculations for a third shell are presented to illustrate the mechanism of pairing.     

A note on the asymptotic expansion of Feynman amplitudes

Employing the technique given by Bergere and Lam, we determine the asymptotic expansion of Feynman amplitude (in the Schwinger integral representation) when the masses of any subset of internal lines tend to zero.     

Surface morphology of polyethylene glycol films produced by matrix-assisted pulsed laser evaporation (MAPLE): Dependence on substrate temperature

The dependence of the surface morphology on the substrate temperature during film deposition was investigated for polyethylene glycol (PEG) films by matrix-assisted pulsed laser evaporation (MAPLE). The surface structure was studied with a combined technique of optical imaging and AFM measurements. There was a clear difference between the films produced below and above the melting point of PEG. For temperatures above the melting point, the polymer material was distributed non-uniformly over the substrate with growths areas, where cluster-like structures merge into large islands of micrometer size. At these temperatures, the islands in the investigated growth areas cover most of the bottom layer which has a typical height of 50-150 nm.     

Complexation of lanthanide nitrates

Summary The change of the stability constantsK ⁰ ₁ of the lanthanide nitrato complexes in the lanthanide series is presented and discussed from the viewpoint of the interaction between the first and second hydration sheath of lanthanide ions.

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Komplexierung bei Lanthaniden-Nitraten

Zusammenfassung Es wird der Verlauf der StabilitätskonstantenK ⁰ ₁ von Nitrato-Komplexen in der Lanthanidenreihe vorgestellt und auf Basis von Wechselwirkungen zwischen der ersten und zweiten Hydrat-Schicht der Lanthaniden-Ionen diskutiert.

     

In Vitro Screening of Bioactive Compounds in some Gluten-Free Plants

Electrophoretic, antioxidant, and FTIR profiles of some varieties of amaranth, quinoa, and buckwheat seeds and their by products were compared. Water extracts of these products were evaluated by the Folin–Ciocalteau method in order to determine total phenolic content. The antioxidant activities were determined by 2,2′-azobis-2-methyl-propanimidamide, ferric-reducing/antioxidant power, and cupric reducing antioxidant capacity radical scavenging assays. FTIR spectra showed the secondary structure of pseudocereals in the ranges of amides I, II, and III shifts. Results of evaluated methods could be used to control several products (seeds, flours, extracts, flakes, roasting) with high phenolic content and antioxidant activity suitable for supplementation in food applications.

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Graphical Abstract ?

     

On the ground state eigenfunction of a convex domain in Euclidean space

We study the first eigenfunction ₁ of the Dirichlet Laplacian on a convex domain in Euclidean space. Elementary properties of Bessel functions yield that if D is a sector in Euclidean plane with area 1 and the angle tends to 0. We aim to characterize those domains D such that is large in terms of the ratio of the first eigenvalue of D and the infimum of the first eigenvalues of all subdomains D of D with given volume.Research supported by the Deutsche Forschungsgemeinschaft