105 research outputs found

    Chances of Employment in a Population of Women and Men after Surgery of Congenital Heart Disease: Gender-Specific Comparisons between Patients and the General Population

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    It was examined whether women and men (17-45 years) with operated congenital heart disease (CHD) differ with respect to chances of employment. Patients were compared with the general population. Patients (N=314) were classified by type of surgery (curative, reparative, palliative) as indicator of initial severity of disease. The second classification was performed according to a system proposed by the New York Heart Association in order to take subjectively reported impairments into account. Controls (N=1165) consisted of a 10% random sample drawn from the German Socio-Economic Panel. Chances of full- time employment decreased as disease severity increased. Chances of part- time and minor employment were higher in patients than among controls. These general effects were due to male patients, while the employment patterns of women did not differ from the control group. Independently of patient status women were more likely to have lower rates of full- time employment, and the rates of part- time and minor employment were higher. Long- term adaptation to impairments due to congenital heart disease differs between women and men with respect to employment status. While female patients do not differ from the general population, males may lower their engagement in paid work.

    Synthesis and Characterization of Mussel Adhesive Peptides

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    Mussels, marine organisms, attach to underwater surfaces by making a byssus, which is an extra-corporeal bundle of tiny tendons attached distally to a foreign surface and proximally by insertion of the root into the byssal retractor muscles. The interaction exterior of byssus and marine surface is an adhesive plaque that contains different proportion of five mytilus edulis adhesive proteins (mefp-1 to 5). Relatively high contains of Lys, L-3,4-dihydroxyphenylalanine (DOPA), trans-4-hydroxyproline, and trans-2,3-cis-3,4-dihydroxyproline formulates MAPs as an adhesive protein. Derivation of synthetic bio-adhesives from MAPs have been limited due to fairly unsuccessful synthesize adhesive polypeptides and poor yield in extraction from biological source. In this study, syntheses of mussel adhesive protein analogues have been performed. Several oligomers and polymers were synthesized with the comibation of bicyclic dipeptide building blocks, DOPA, Lys and Tyr. Use of bicyclic dipeptide building block has advantage over use of Hyp and Ser as former is expensive and latter needs side chain protection. Molecular structure, mass and size of these polymers were characterized using various techniques like NMR, MALDI, and GPC. The adhesive property of these polymers was tested using DOSY NMR experiment and AFM spectroscopy. Results obtained using AFM shows adhesion of poly-Lys-Bic-Tyr to graphite surface. These results open up a wide area in which finely tuned adhesive synthetic bio-polymers can be synthesized

    Synthetic Lipoteichoic Acid from Staphylococcus aureus Is a Potent Stimulus of Cytokine Release

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    We recently purified lipoteichoic acid (LTA) from Staphylococcus aureus to more than 99% purity by a novel preparation method and deduced its structure with the first nuclear magnetic resonance (NMR) of a complete LTA. In contrast to Gram-negative lipopolysaccharides, this LTA requires the toll-like receptor (TLR)-2 and not TLR-4 for cytokine induction in monocytes and macrophages. To elucidate the structure–function relationships for LTA from S. aureus, the lipid anchor was prepared by either acidic hydrolysis of native LTA or chemical synthesis (gentiobiosyl-sn-dimyristoylglycerol). Next, a complete LTA molecule with six glycerophosphate units carrying four alanine plus one N-acetyl-glucosamine substituent was synthesized, which displayed the same potency to activate monocytes as native LTA. However, 100–1,000 times higher concentrations of the lipid anchor were required for cytokine induction. It is worthy to note that replacing d-alanine with l-alanine blunted the effect indicating stereoselective recognition. The structure identification of this synthesized and biologically active LTA was proven by NMR and matrix-assisted laser desorption-ionization mass spectrometry. We concluded that the lipid anchor, with its fatty acids, represents an integral part of the immunostimulatory activity of LTA, but requires additional structural components on the polyglycerophosphate backbone

    Selective photodissociation of tailored molecular tags as a tool for quantum optics

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    Recent progress in synthetic chemistry and molecular quantum optics has enabled demonstrations of the quantum mechanical wave–particle duality for complex particles, with masses exceeding 10 kDa. Future experiments with even larger objects will require new optical preparation and manipulation methods that shall profit from the possibility to cleave a well-defined molecular tag from a larger parent molecule. Here we present the design and synthesis of two model compounds as well as evidence for the photoinduced beam depletion in high vacuum in one case

    The ash dispersion over Europe during the Eyjafjallajökull eruption e Comparison of CMAQ simulations to remote sensing and air-borne in-situ observations

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    The dispersion of volcanic ash over Europe after the outbreak of the Eyjafjallajökull on Iceland on 14 April 2010 has been simulated with a conventional three-dimensional Eulerian chemistry transport model system, the Community Multiscale Air Quality (CMAQ) model. Four different emission scenarios representing the lower and upper bounds of the emission height and intensity were considered. The atmospheric ash concentrations turned out to be highly variable in time and space. The model results were compared to three different kinds of observations: Aeronet aerosol optical depth (AOD) measurements, Earlinet aerosol extinction profiles and in-situ observations of the ash concentration by means of optical particle counters aboard the DLR Falcon aircraft. The model was able to reproduce observed AOD values and atmospheric ash concentrations. Best agreement was achieved for lower emission heights and a fraction of 2% transportable ash in the total volcanic emissions. The complex vertical structure of the volcanic ash layers in the free troposphere could not be simulated. Compared to the observations, the model tends to show vertically more extended, homogeneous aerosol layers. This is caused by a poor vertical resolution of the model at higher altitudes and a lack of information about the vertical distribution of the volcanic emissions. Only a combination of quickly available observations of the volcanic ash cloud and atmospheric transport models can give a comprehensive picture of ash concentrations in the atmosphere

    Isotope-selective high-order interferometry with large organic molecules in free fall

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    Interferometry in the time domain has proven valuable for matter-wave based measurements. This concept has recently been generalized to cold molecular clusters using short-pulse standing light waves which realized photo-depletion gratings, arranged in a time-domain TalbotâEuro"Lau interferometer (OTIMA). Here we extend this idea further to large organic molecules and demonstrate a new scheme to scan the emerging molecular interferogram in position space. The capability of analyzing different isotopes of the same monomer under identical conditions opens perspectives for studying the interference fringe shift as a function of time in gravitational free fall. The universality of OTIMA interferometry allows one to handle a large variety of particles. In our present work, quasi-continuous laser evaporation allows transferring fragile organic molecules into the gas phase, covering more than an order of magnitude in mass between 614 amu and 6509 amu, i.e. 300% more massive than in previous OTIMA experiments. For all masses, we find about 30% fringe visibility

    Isotope-selective high-order interferometry with large organic molecules in free fall

    Get PDF
    Interferometry in the time domain has proven valuable for matter-wave based measurements. This concept has recently been generalized to cold molecular clusters using short-pulse standing light waves which realized photo-depletion gratings, arranged in a time-domain TalbotâEuro"Lau interferometer (OTIMA). Here we extend this idea further to large organic molecules and demonstrate a new scheme to scan the emerging molecular interferogram in position space. The capability of analyzing different isotopes of the same monomer under identical conditions opens perspectives for studying the interference fringe shift as a function of time in gravitational free fall. The universality of OTIMA interferometry allows one to handle a large variety of particles. In our present work, quasi-continuous laser evaporation allows transferring fragile organic molecules into the gas phase, covering more than an order of magnitude in mass between 614 amu and 6509 amu, i.e. 300% more massive than in previous OTIMA experiments. For all masses, we find about 30% fringe visibility

    Pushing the mass limit for intact launch and photoionization of large neutral biopolymers

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    Since their first discovery by Louis Dunoyer and Otto Stern, molecular beams have conquered research and technology. However, it has remained an outstanding challenge to isolate and photoionize beams of massive neutral polypeptides. Here we show that femtosecond desorption from a matrix-free sample in high vacuum can produce biomolecular beams at least 25 times more efficiently than nanosecond techniques. While it has also been difficult to photoionize large biomolecules, we find that tailored structures with an abundant exposure of tryptophan residues at their surface can be ionized by vacuum ultraviolet light. The combination of these desorption and ionization techniques allows us to observe molecular beams of neutral polypeptides with a mass exceeding 20,000 amu. They are composed of 50 amino acids – 25 tryptophan and 25 lysine residues – and 26 fluorinated alkyl chains. The tools presented here offer a basis for the preparation, control and detection of polypeptide beams

    Crystal Phase Transitions in the Shell of PbS CdS Core Shell Nanocrystals Influences Photoluminescence Intensity

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    ABSTRACT We reveal the existence of two different crystalline phases, i.e., the metastable rock salt and the equilibrium zinc blende phase within the CdS shell of PbS CdS core shell nanocrystals formed by cationic exchange. The chemical composition profile of the core shell nanocrystals with different dimensions is determined by means of anomalous small angle X ray scattering with subnanometer resolution and is compared to X ray diffraction analysis. We demonstrate that the photoluminescence emission of PbS nanocrystals can be drastically enhanced by the formation of a CdS shell. Especially, the ratio of the two crystalline phases in the shell significantly influences the photoluminescence enhancement. The highest emission was achieved for chemically pure CdS shells below 1 nm thickness with a dominant metastable rock salt phase fraction matching the crystal structure of the PbS core. The metastable phase fraction decreases with increasing shell thickness and increasing Exchange times. The photoluminescence intensity depicts a constant decrease with decreasing metastable rock salt phase fraction but Shows an abrupt drop for shells above 1.3 nm thickness. We relate this effect to two different transition mechanisms for changing from the metastable rock salt phase to the equilibrium zinc blende phase depending on the shell thicknes
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