Recognition of chiral anions using calix[4]arene-based ureido receptor in the 1,3-alternate conformation

A new type of calixarene-based receptor designed for the recognition of chiral anions was prepared by the introduction of (S)-2-methylbutan-1-ol moieties into the lower rim of calixarene. The immobilization of calixarene skeleton in the 1,3-alternate conformation enabled the construction of a cavity consisting of preorganised ureido functions and chiral substituents in close proximity. This cavity is capable of chiral discrimination of selected anions as demonstrated on d- and l-phenylalaninates.     

Palladium‐Catalyzed Stereoselective Intramolecular Oxidative Amidation of Alkenes in the Synthesis of 1,3‐ and 1,4‐Amino Alcohols and 1,3‐Diamines

An efficient and practical Pd‐catalyzed intramolecular oxidative allylic amidation provides facile access to derivatives of 1,3‐ and 1,4‐amino alcohols and 1,3‐diamines. The method operates under mild reaction conditions (RT) with molecular oxygen (1 atm) as the sole reoxidant of Pd. Excellent diastereoselectivities were attained with substrates bearing a secondary stereogenic center     

X‐ray collimation by crystals with precise parabolic holes based on diffractive–refractive optics

Two crystals with precise parabolic holes were used to demonstrate sagittal beam collimation by means of a diffractive–refractive double‐crystal monochromator. A new approach is introduced and beam collimation is demonstrated. Two Si(333) crystals with an asymmetry angle of α = 15° were prepared and arranged in a dispersive position (+,?,?,+). Based on theoretical calculations, this double‐crystal set‐up should provide tunable beam collimation within an energy range of 6.3–18.8 keV (Θ_B = 71–18.4°). An experiment study was performed on BM05 at ESRF. Using 8.97 keV energy, the beam profile at various distances was measured. The experimental results are in good agreement with theoretical predictions. Owing to insufficient harmonic suppression, the collimated (333) beam was overlapped by horizontally diverging (444) and (555) beams.     

MSSM Higgs sector at the one-loop level

This work provides an elementary introduction to the Higgs sector renormalisation within the Minimal Supersymmetric Standard Model (MSSM) framework. The main aim of the paper is to clarify some technical details that are usually omitted in the existing literature. The MSSM tree-level relation m _h ² + m _H ² = m _A ² + m _Z ² is renormalised using the standard technique of direct computation of the relevant one-loop Feynman diagrams. The calculation is performed within the unitary gauge and the definition of the renormalised parameters is briefly reviewed. The expected cancellation of ultraviolet divergences is explicitly checked and the well-known leading-log term is recovered. All the necessary ingredients of the computations are summarized in the appendices which makes the work more self-contained.     

Mass spectrometry in drug metabolism and pharmacokinetics: Current trends and future perspectives

Drug Metabolism and Pharmacokinetics (DMPK) is a core scientific discipline within drug discovery and development as well as post‐marketing. It helps to design and select the most promising drug candidate and obtain advanced insights on the processes that control absorption, distribution, metabolism and excretion (ADME) of the final drug candidate. Mass spectrometry is one of the key technologies applied in DMPK. Therefore, the continuous advances made in the field of mass spectrometry also directly impact the way in which we investigate the ADME properties of a compound, providing us with new tools to gather more information or improve our efficiency. An overview will be given of some important current trends and future perspectives in the field.     

EPR study of neutron irradiated Ge-S glasses

The results of EPR measurements on neutron irradiated Ge-S glasses doped by Mn are presented. It has been found that the integrated neutron flux from 1·1 × 10¹⁵ n. cm^–2 to 1·5× × 10¹⁷n. cm^–2 has no detectable effect on the nearest neighbour surroundings of Mn²⁺ probing ions but increases the intensity of all EPR lines. A new EPR line was detected in Mn-doped Ge-S glasses irradiated with the highest neutron dose of 1·5 × 10¹⁷ n. cm^–2.     

Über die an „Schwachen“ Grenzflächen Entstehenden Kopfwellen

Zusammenfassung In der vorliegenden Arbeit werden die Kopfwellen untersucht, die beim Auffallen einer harmonischen Schall-Kugelwelle auf die Ebene Grenzfläche zwischen zwei flüssigen Medien entstehen. Vorausgesetzt wird, daß die Grenzfläche schwach ist, d. h. daß die Geschwindigkeit der Schallwellen im Medium mit der Erregungsquelle nur um weniges kleiner ist als die Geschwindigkeit der Schallwellen im Medium ohne die Quelle.

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Low-frequency instability of an inhomogeneous weakly ionized plasma in crossed electric and inhomogeneous magnetic fields

The paper discusses the drift dissipative instability that arises in a weakly ionized inhomogeneous plasma in crossed electric and magnetic fields. The potential perturbations are studied in the WKB (Wentzel-Krammers-Brillouin) approximation, i.e. for k = d lnn ₀/dx. The critical magnetic field, beyond the value of which the plasma is again stable against the studied perturbations, is computed. The effect of the inhomogeneity of the magnetic field modelled by a gravitational field is analyzed and the effect of a magnetic field, growing in the direction opposite to that of the plasma density, is pointed out. Under certain circumstances similar phenomena also arise in the current-convective instability.The author wishes to express his thanks to J. Václavík, K. Jungwirth and J. Preinhaelter for their stimulating discussions and comments.     

Weak solutions for steady compressible Navier-Stokes-Fourier system in two space dimensions

We consider steady compressible Navier-Stokes-Fourier system in a bounded two-dimensional domain. We show the existence of a weak solution for arbitrarily large data for the pressure law p(ϱ, ϑ) ∼ ϱ ^γ + ϱϑ if γ > 1 and p(ϱ, ϑ) ∼ ϱ ln ^α (1 + ϱ) + ϱϑ if γ = 1, α > 0, depending on the model for the heat flux.