Education in medical genetics for physicians: Germany

We have assessed the relative amount of genetics education at each of the 3 levels of medical training in Germany, namely the undergraduate, postgraduate and continuous medical education stages. Our data show that genetics is ill represented at all levels. Written examinations at the end of the relevant section at the undergraduate level include very few questions related to medical genetics, and particularly few in subjects such as pathology, internal medicine and gynaecology and obstetrics. At the postgraduate level, only 4 specialties require knowledge in medical genetics that may be subject to examination. At the continuous medical education level, medical genetics plays a very minor role. All 3 levels have been subject to reform in recent years, but effects that might ensue from these reforms cannot be expected before 2008.     

One-year time series of investigations of analytes within human breath using ion mobility spectrometry

Ion mobility Spectrometry is used to detect volatile analytes within human breath directly. Many volatile organic compounds (VOC) show significant day-to-day variation in the signal height related to the concentration of the analyte, although the breath collection had been performed under the same conditions with respect to similar sampling procedure, similar dead volume, similar measurement time, and measurement conditions. Variations of 8 different analytes are investigated over a time period of 11 months in the exhaled breath of the same person in the same room environment. The individual variability is reported for Benzothiazole; D-Limonene; Eucalyptol; Decamethylcyclopentasiloxane; Decanal; 1-Hexanol, 2-ethyl-; Cyclohexanone, 5-methyl-2-(1-methylethyl) and Nonanal. The paper shows, that the individual variability must be taken into consideration to relate the findings to medical questions. Therefore, the room air concentration of VOCs must be taken into account, so that the difference between exhaled and inhaled air has to be used as indicator. Finally, starting with individual variabilities, the normal variation related to the specific analyte should be considered in addition.     

Rhenium oxo compounds containing eta2-pyrazolate ligands

Reaction of potassium salts of sterically demanding pyrazolates (pz = bis-3,5-tert-butylpyrazolate, pz= bis-3,5-tert-butyl-4-methylpyrazolate) with Re2O7 affords soluble eta2-pyrazolate complexes of the type [(eta2-pz)ReO3(THF)n](1: pz, n= 1 and 2: pz, n= 0). They were characterized by spectroscopic methods and by X-ray crystallography confirming the eta2-coordinate ligands. Complex 1 employing the ligand with a proton in the 4-position retains one molecule of THF, whereas the additional methyl group in 2 leads to the base-free compound 2. Compound 1 reacts with pyridine and 3,5-dimethylpyridine to form Lewis base adducts of the type [(eta2-pz)ReO3(L)](3: L = py; 4: L = 3,5-Me2py). The pronounced sensitivity towards water of these complexes is demonstrated by the reaction of 1 with one equivalent of water forming the corresponding pyrazolium perrhenate [ReO4][pzH2](5). Its solid state structure shows a hydrogen bonded dimeric assembly. Catalytic activity of 1 is established in oxygen atom transfer-reactions (OAT) from dimethylsulfoxide to triphenylphosphine, and in epoxidations of cyclooctene employing bis(trimethylsilyl) peroxide (BTSP).     

Reaction behaviour of dinuclear copper(I) complexes with m-xylyl-based ligands towards dioxygen

Intramolecular ligand hydroxylation was observed during the reactions of dioxygen with the dicopper(I) complexes of the ligands L(1)(L(1)=alpha,alpha'-bis[(2-pyridylethyl)amino]-m-xylene) and L(3)(L(3)=alpha, alpha'-bis[N-(2-pyridylethyl)-N-(2-pyridylmethyl)amino]-m-xylene). The dinuclear copper(I) complex [Cu(2)L(3)](ClO(4))(2) and the dicopper(II) complex [Cu(2)(L(1)-O)(OH)(ClO(4))]ClO(4) were characterized by single-crystal X-ray structure analysis. Furthermore, phenolate-bridged complexes were synthesized with the ligand L(2)-OH (structurally characterized [Cu(2)(L(2)-O)Cl(3)] with L(2)=alpha, alpha'-bis[N-methyl-N-(2-pyridylethyl)amino]-m-xylene; synthesized from the reaction between [Cu(2)(L(2)-O)(OH)](ClO(4))(2) and Cl(-)) and Me-L(3)-OH: [Cu(2)(Me-L(3)-O)(mu-X)](ClO(4))(2)xnH(2)O (Me-L(3)-OH = 2,6-bis[N-(2-pyridylethyl)-N-(2-pyridylmethyl)amino]-4-methylphenol and X = C(3)H(3)N(2)(-)(prz), MeCO(2)(-) and N(3)(-)). The magnetochemical characteristics of compounds were determined by temperature-dependent magnetic studies, revealing their antiferromagnetic behaviour [-2J(in cm(-1)) values: -92, -86 and -88; -374].     

Influence of dextran coating on the magnetic behaviour of iron oxide nanoparticles

Magnetic iron oxide nanoparticles with mean diameters in the range from 10 to 30 nm were prepared by modified chemical precipitation routes. The particles were suspended in an aqueous solution by coating of the particles with carboxymethyldextran. A stability against agglomeration was achieved over a period of more than 7 days. In the present investigation, the structural and the magnetic properties of the nanoparticles were investigated. The influence of the dextran shell on the strength of the dipole–dipole interactions between the neighbouring particles was determined by investigation of the remanence behaviour (Henkel plot) of coated as well as of uncoated particles.     

Synthesis of the stabilized active metabolite of clopidogrel

The convergent synthesis of the stabilized active metabolite of clopidogrel was achieved in eleven steps from commercially available 1,2,3,6-tetrahydropyridine and 2-bromo-3′-methoxy acetophenone (MPBr). This synthetic route used a standard Horner–Wadsworth–Emmons reaction allowing the introduction of a Z exocyclic double bond. A selective hydrolysis of an acrylic methyl ester moiety, isolated by an efficient and reliable preparative chiral chromatography at gram scale, released the title compound with a 98% LC purity and d.e. >99%.     

Electrochemically deposited palladium as a substrate for self-assembled monolayers

The vast majority of reports of self-assembled monolayers (SAMs) on metals focus on the use of gold. However, other metals, such as palladium, platinum, and silver offer advantages over gold as a substrate. In this work, palladium is electrochemically deposited from PdCl2 solutions on glassy carbon electrodes to form a substrate for alkanethiol SAMs. The conditions for deposition are optimized with respect to the electrolyte, pH, and electrochemical parameters. The palladium surfaces have been characterized by scanning electron microscopy (SEM) and the surface roughness has been estimated by chronocoulometry. SAMs of alkane thiols have been formed on the palladium surfaces, and their ability to suppress a Faradaic process is used as an indication for palladium coverage on the glassy carbon. The morphology of the Pd deposit as characterized by SEM and the blocking behavior of the SAM formed on deposited Pd delivers a consistent picture of the Pd surface. It has been clearly demonstrated that, via selection of experimental conditions for the electrochemical deposition, the morphology of the palladium surface and its ability to support SAMs can be controlled. The work will be applied to create a mixed monolayer of metals, which can subsequently be used to create a mixed SAM of a biocomponent and an alkanethiol for biosensing applications.     

Fracture and cavitation in a constrained thin metal layer under a scale effect in layered materials

Dislocation activities are confined within a thin metal layer. Therefore instead of continuum plasticity theory, individual dislocation activities are considered in order to analyse their effects on fracture, especially interface fracture. Three failure modes may occur in the thin ductile layer: interface fracture, metal fracture and metal cavitation. These failure modes are studied and the competition between them is examined. It seems that interface fracture occurs prior to metal fracture provided that the cohesive strengths of the interface and the metal are similar. In general, the fracture toughness of the thin layer will increase with increasing layer thickness. However, at a layer thickness of about 10 mm, the layer is more likely to fail by interface debonding, prior to any failure by ductile cavitation. Finally, using material and geometric parameters, a relation is given which determines the competition between crack fracture and cavity instability.     

Gas-phase structures of neutral silicon clusters

Vibrational spectra of neutral silicon clusters Si(n), in the size range of n = 6-10 and for n = 15, have been measured in the gas phase by two fundamentally different IR spectroscopic methods. Silicon clusters composed of 8, 9, and 15 atoms have been studied by IR multiple photon dissociation spectroscopy of a cluster-xenon complex, while clusters containing 6, 7, 9, and 10 atoms have been studied by a tunable IR-UV two-color ionization scheme. Comparison of both methods is possible for the Si(9) cluster. By using density functional theory, an identification of the experimentally observed neutral cluster structures is possible, and the effect of charge on the structure of neutrals and cations, which have been previously studied via IR multiple photon dissociation, can be investigated. Whereas the structures of small clusters are based on bipyramidal motifs, a trigonal prism as central unit is found in larger clusters. Bond weakening due to the loss of an electron leads to a major structural change between neutral and cationic Si(8).     

Crystalline morphology in polymer blends via competition with spinodal decomposition

Miscible polymer blends containing one crystallizable component and exhibiting liquid-liquid phase separation at elevated temperatures [lower critical solution temperature (LCST) behavior] offer an excellent possibility of controlling morphology and thus mechanical properties. For instance, if a homogeneous mixture of dissimilar polymers is allowed to undergo a rapid temperature jump from below LCST to above LCST, spinodal decomposition takes place and a highly interconnected two-phase morphology with uniform domain size (so-called modulated structure) develops. By quenching the phase-separated system below the glass transition temperature after an appropriate time of phase separation, one is able to fix this characteristic morphology [1]. By quenching the phase-separated blend below the melting point of the crystallizable component to different supercooling depths, it is possible to control the number of nuclei and thus the spherulite's size, creating more or less ordered structures.