Über die Einwirkung der Reductionsmittel auf Cholsäure

Ohne Zusammenfassung     

Pulsed bed calorimetry

Conventional calorimetry has always the difficulty of choosing between near to equilibrium working conditions and high thermal ramp rates. Thus, either the transport phenomena and sample homogeneities are good but the signals become weak due to thermal losses, or the signals are sharp, but strong gradients across the sample lead to chemical and thermal heterogeneities. The described pulsed fluidized bed technique, by strongly stirring the sample, allows good sample homogeneities even at high ramp rates. Moreover, the permanently regenerated cover gas allows as well a good heat transfer towards the thermocouples as a constant atmosphere composition leading to very precise onset temperatures.     

Tractor beam for fully immersed multiple objects: Long distance pulling,trapping, and rotation with a single optical set‐up

In this article, we have theoretically demonstrated the mechanism of an active tractor beam for multiple fully immersed objects with additional abilities to yielding stable long distance levitation, a controlled rotation and a desired 3D trapping. This is demonstrated with a single optical set‐up by using two coaxial, or even non‐coaxial, superimposed higher order monochromatic Bessel beams of reverse helical nature and different frequencies. The superimposed beams can possess periodic intensity variations both along and around the beam‐axis due to a difference in longitudinal wave‐numbers and beam orders, respectively. The difference in frequencies of the two laser beams makes the intensity pattern to move along and around the beam‐axis in a continuous way without manual ramping of phase, which allows for bidirectional movement of completely immersed multiple particles. The condition for increasing or decreasing the dimension of binding regions is also proposed here to manipulate multiple immersed objects of different sizes under dipole approximation.

     

Efficient One-Pot Synthesis of Substituted Pyrido[2,3-d]pyrimidines from Vinamidinium and Chloropropeniminium Salts

A novel and efficient one-pot preparation of 6-substituted pyrido-[2,3-d]pyrimidines by cyclocondensation of 6-amino-1,3-dimethyluracil with symmetrical vinamidinium salts under basic conditions has been developed. Regioselectivity was observed with an unsymmetrical chloropropeniminium salt.     

Mass spectrometry as a tool for the selective profiling of destruxins; their first identification in Lecanicillium longisporum

Mass spectrometry was applied to the identification of the destruxins (dtxs), cyclic peptides that are commonly produced by the fungal insect‐pathogen, Metarhizium anisopliae. The aim of the study was to optimise a methodology in order to firstly determine whether these compounds were present in other species and to determine the effect of differing growth conditions upon the dtx content detected. Matrix‐assisted laser desorption/ionisation time‐of‐flight mass spectrometry (MALDI‐ToF‐MS) was initially used to analyse the dtxs, but limitations were indicated. Nano‐scale high‐performance liquid chromatography/electrospray ionisation mass spectrometry (HPLC/ESI‐MS) and automated ‘data‐dependent’ tandem mass spectrometric (MS/MS) analysis were also applied, utilising characteristic neutral losses during fragmentation to confirm the presence of the dtxs. This latter approach distinguished the dtx E and B isoforms by retention time and diagnostic neutral losses during fragmentation allowing extraction of the destruxin data from a complex dataset. This process revealed the presence of a number of dtxs in the fungal species Lecanicillium longisporum, a species previously not known to produce dtxs, and dtx production in this species was shown to be significantly higher in aerated cultures compared with still cultures. Copyright © 2009 John Wiley & Sons, Ltd.     

Problème de Dirichlet relatif à une perturbation non lineaire des espaces harmoniques

In this paper, we prove for a more general semi-linear perturbation of linear harmonic spaces, the existence and the unicity of the solution of the Dirichlet problem and we apply our results for the non-linear stationary Schrödinger equation.     

Large shift and small broadening of Br2 valence band upon dimer formation with H2O: an ab initio study

Valence electronic excitation spectra are calculated for the H(2)O···Br(2) complex using highly correlated ab initio potentials for both the ground and the valence electronic excited states and a 2-D approximation for vibrational motion. Due to the strong interaction between the O-Br and the Br-Br stretching motions, inclusion of these vibrations is the minimum necessary for the spectrum calculation. A basis set calculation is performed to determine the vibrational wave functions for the ground electronic state and a wave packet simulation is conducted for the nuclear dynamics on the excited state surfaces. The effects of both the spin-orbit interaction and temperature on the spectra are explored. The interaction of Br(2) with a single water molecule induces nearly as large a shift in the spectrum as is observed for an aqueous solution. In contrast, complex formation has a remarkably small effect on the T = 0 K width of the valence bands due to the fast dissociation of the dihalogen bond upon excitation. We therefore conclude that the widths of the spectra in aqueous solution are mostly due to inhomogeneous broadening.     

Chemical composition and antioxidant activity of the essential oil of Juniperus phoenicea L. berries

This study is designed to examine the chemical composition and antioxidant activity of the essential oil of Juniperus phoenicea L. ripe and unripe berries. GC and GC/MS analyses resulted in the detection of 42 components representing approximately 96.50-99.57% of the oils. Major components of the oils were α-pinene (58.61-77.39%), camphene (0.67-9.31%), δ-3-carene (0-10.01%) and trans-verbenol (0-5.24%). Antioxidant activities were determined by two different test systems, DPPH and ABTS radical scavenging activities. In both systems ripe berries exhibited better activity potential than the unripe ones.