Synthesis of new racemic and optically active N‐phosphonoalkyl bicyclic β‐amino acids via the kabachnik–fields reaction as potential biologically active compounds

Novel racemic and optically active constrained N‐phosphonoalkyl bicyclic β‐amino acids have been synthesized via the Kabachnik–Fields reaction of the (RS) or (R)‐1‐aminobicyclo[2.2.2]octane‐2‐carboxylic acids with paraformaldehyde and benzaldehyde, and the dimethyl‐H‐phosphonate. The structure of obtained compounds was characterized by NMR (¹H, ¹³C, and ³¹P), LC/MS, and X‐ray diffraction analyses. © 2012 Wiley Periodicals, Inc. Heteroatom Chem 23:123–130, 2012; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20759     

DieD-Klassen der Endlichen Symmetrischen Halbgruppen Und Ihre Mächtigkeiten-Klassen der Endlichen Symmetrischen Halbgruppen Und Ihre Mächtigkeiten

Ohne ZusammenfassungDie Forschungsarbeit entstand mit Unterstützung der Alexander von Humboldt-Stiftung.     

Nonstationary quantum mechanics. IV. Nonadiabatic properties of the Schrödinger equation in adiabatic processes

It is shown that the nonstationary Schrödinger equation does not satisfy a well-known adiabatical principle in thermodynamics. A renormalization procedure based on the possible existence of a time-irreversible basic evolution equation is proposed with the help of which one comes to agreement in a variety of specific cases of an adiabatic inclusion of a perturbing potential. The ideology of the present article IV rests essentially on the ideology of the preceding articles, in particular article I.     

Surface forces in foam films from DPPC and lung surfactant phospholipid fraction

Surface properties of foam films formed from aqueous dispersions of dipalmitoyl-phosphatidylcholine (DPPC) and from solutions of a phospholipid fraction of lung surfactant (TPL) are studied employing the foam film method. Experiments are carried out within a wide range of NaCl concentrations (C_el) and the ranges of C_el determining formation of common films (CF), common black films (CBF) and bilayer Newton black films (NBF) are found. The thickness (h) of the CF and CBF decreases with the increase of C_el until the critical electrolyte concentrations (C_{el, cr}) is reached. The determined C_{el, cr} that characterize the transition to NBF show that C_{el, cr} of the TPL films is an order of magnitude higher than that of the DPPC films. The measured h of the TPL films is higher than that of the DPPC films in the whole C_el range. Besides, only the h(C_el) curve of the DPPC films outlines a metastable C_el range where both CF and NBF are obtained. Both the h(C_el) curves and the direct measurements of the disjoining pressure isotherms of the DPPC films (Π(h) isotherms) demonstrate the role of electrostatic repulsive forces for the stability of the phospholipid films The obtained results are compared with the DLVO theory equations and the evaluated potentials of the diffuse electric layer φ₀  20 mV for the DPPC films and φ₀  100 mV for TPL films show the strong effect of the charged phospholipids in the TPL mixture on the electric properties at the film interfaces.     

Runaway Electron Beam Instability in Slide-Away Discharges in the HT-7 Tokamak

Slide-away discharges are achieved by decreasing the plasma density or ramping down the plasma current in runaway discharges in the HT-7 tokamak. In the case of plasma current ramp down, the ratio of the electron plasma frequency to the electron cyclotron frequency is higher than in the stationary pulses when the discharge goes into a slide-away regime. The instability regime is characterized by relaxations in the electron cyclotron emission due to relativistic anomalous Doppler effect which transfers energy from parallel to perpendicular motion. The triggering of relativistic anomalous Doppler effect at higher density by ramping down of plasma current may provide a alternative runaway energy control scenario.     

Photoinduced dichroism in additively coloured KCl: Na at room temperature

Spectral and kinetic investigations of the reversible photoinduced dichroism in KCl : Na containing F_A and F_A + F_B centers are done. It is suggested that in presence of F_B centers the observed 〈100〉 and 〈110〉 dichroism is connected with the F_B(II) centers.     

Hologram recording in cadmium and copper doped cadmium sulphide

Photoinduced changes in the optical absorption of large crystals of cadmium sulphide doped with cadmium and copper, are used to store Bragg-angle holograms by means of a He-Ne laser. The recordings are stable in the dark at room temperature and can be erased either optically or thermally. Diffraction efficiencies of over 1% at a write energy of about 1J/cm² are obtained.     

A remark on the definition of superselection rules in terms of unbounded operators

The mathematical definition of superselection rules in the case when observables are described by unbounded operators in a fixed Hilbert space (for instance, in the frame of Wightman's axioms) is examined. The additional condition \(P_{H_q } D \subset D\) (whereD is the common domain of definition of the operators,H _q is theqth sector, and \(P_{H_q } \) is the projection onH _q ) is found to be sufficient in order to preserve-as in the case of bounded observables—the one-to-one correspondence between reducing subspacesH _q and projections \(P_{H_q } \) from the commutantA′ of the algebraA of observables. This additional condition is equivalent to the physical requirement that every physical vector state can be uniquely represented as a linear combination of physical states, each belonging to some sector.     

Structural analysis of the tripeptide glycyle-methionyl-glycine (H-Gly-Met-Gly-OH) and its hydrochloride

As part of an investigation on the coordination ability of peptides, structural analyses of the solid tripeptide glycyl-methionyl-glycine (H-Gly-Met-Gly-OH) and its hydrochloride have been carried out. The quantum chemical calculations (B3LYP/6-31+G(d) and UHF/6-31G^**) and linear-dichroic infrared (IR-LD) spectroscopy predict a near to linear structure of the pure ligand, but the experimental IR-LD data are in accordance with a cross-linked disposition of both amide fragments in the protonated form. This result is confirmed by an X-ray diffraction study of latter compound. The presented work also demonstrates the possibilities of IR-LD spectral analysis for the structural characterization of an amorphous system such as the investigated tripeptide.