Test of electron screening and vacuum polarization in heavy muonic atoms

Energies of higherΜ X-rays have been measured in¹⁰³Rh,^natHg and²⁰³Tl to test the vacuum polarization correction and the electron screening effect in heavy muonic atoms. For tests of the energy calibration delayed nuclearγ-rays from theΜ-capture reaction were used. The experimental data agree to better than 4% with self-consistent Hartree-Fock calculations of the electron screening. Transitions which are sensitive to the vacuum polarization correction mainly, verify the calculations to better than 1.5%. Comparing all at present existing experiments with latest calculations no significant deviation of more than 0.7% of the vacuum polarization correction can be deduced.     

Struktur von Cantharidin,C10H12O4

Structure of Cantharidine, C₁₀H₁₂O₄ An X-ray structure determination of the title compound confirms the correctness of the molecular stereochemistry as deduced earlier from chemical considerations.     

The rediscovery of Alfred Werner's second hexol

A compound originally prepared by Alfred Werner but structurally misassigned has been shown by three independent X-ray structural analyses to be a hexanuclear species which can now be regarded as Werner's second hexol, his first being that famous for being the first non-carbon containing species to be optically resolved.     

Synthesis and biological evaluation of synthetic viridins derived from C(20)-heteroalkylation of the steroidal PI-3-kinase inhibitor wortmannin

A series of viridin analogs was prepared from wortmannin by nucleophilic ring opening at C(20) and evaluated against the signaling kinases PI-3-kinase and mTOR. Several subnanomolar enzyme inhibitors with orders of magnitude selectivity for PI-3-kinase and strong cytotoxic activity against four cancer cell lines were identified. Among the ten most promising derivatives, six demonstrated lower liver toxicity and greater promise for inhibition of tumor cell growth than the lead structure wortmannin.     

The Complete Asymptotic Expansion for Bernstein–Durrmeyer Operators with Jacobi Weights

The purpose of this paper is the investigation of the local asymptotic behavior of the Bernstein-Durrmeyer polynomials and their derivatives with respect to Jacobi-weights. The main result is the complete asymptotic expansion for these polynomials and their derivatives. All coefficients are calculated explicitely.     

Pressurised hot water extraction in continuous flow mode for thermolabile compounds: extraction of polyphenols in red onions

Extraction and analysis of labile compounds in complex sample matrices, such as plants, is often a big analytical challenge. In this work, the use of a “green and clean” pressurised hot water extraction (PHWE) approach performed in continuous flow mode is explored. Experimental data for extraction and degradation kinetics of selected compounds were utilised to develop a continuous flow extraction (CFE) method targeting thermolabile polyphenols in red onions, with detection by high-performance liquid chromatography (HPLC)–diode array detection (DAD)–mass spectrometry (MS). Water containing ethanol and formic acid was used as extraction solvent. Method performance was focused on extraction yield with minimal analyte degradation. By adjusting the flow rate of the extraction solvent, degradation effects were minimised, and complete extraction could be achieved within 60 min. The CFE extraction yields of the polyphenols investigated were 80–90 % of the theoretically calculated quantitative yields and were significantly higher than the yields obtained by conventional methanol extraction and static batch extraction (70–79 and 58–67 % of the theoretical yields, respectively). The precision of the developed method was lower than 8 % expressed as relative standard deviation.

The topological behaviour of a diffeomorphism near a fixed point

A topological Linearization Theorem for flows by K. Palmer is extended to the case of maps.