Dynamical electron transport through a nanoelectromechanical wire in a magnetic field

We investigate dynamical transport properties of interacting electrons moving in a vibrating nanoelectromechanical wire in a magnetic field. We have built an exactly solvable model in which electric current and mechanical oscillation are treated fully quantum mechanically on an equal footing. Quantum mechanically fluctuating Aharonov-Bohm phases obtained by the electrons cause nontrivial contribution to mechanical vibration and electrical conduction of the wire. We demonstrate our theory by calculating the admittance of the wire which are influenced by the multiple interplay between the mechanical and the electrical energy scales, magnetic field strength, and the electron-electron interaction

Improving estimation of the prognosis of childhood psychopathology; combination of DSM-III-R/DISC diagnoses and CBCL scores [IF: 2.7]

Objective: To compare the predictive validity of the clinical-diagnostic and the empirical-quantitative approach to assessment of childhood psychopathology, and to investigate the usefulness of combining both approaches. Method: A referred sample (N=96), aged 6 to 12 years at initial assessment, was followed up across - on average - a period of 3.2 years. It was assessed to what extent DISC/DSM-III-R diagnoses - representing the clinical-diagnostic approach, and CBCL scores - representing the empirical-quantitative approach, predicted the following signs of poor outcome: outpatient/inpatient treatment, or parents' wish for professional help for the child at follow-up, disciplinary problems in school, and police/judicial contacts. Results: Both diagnostic systems added significantly to the prediction of poor outcome, and neither of the two systems was superior. Use of both systems simultaneously provided the most accurate estimation of the prognosis, reflected by the occurrence of future poor outcome. Even diagnostic concepts that are generally regarded as relatively similar, such as ADHD (DSM) and attention problems (CBCL), or conduct disorder (DSM) and delinquent behavior (CBCL), appeared to differ in their ability to predict poor outcome. Conclusions: The present study supports the use of the empirical-quantitative approach and the clinical-diagnostic approach simultaneously, both in research and in clinical settings, to obtain a comprehensive view of the prognosis of psychopathology in children. © Association for Child Psychology and Psychiatry, 2004

Nucleosomes in gene regulation: theoretical approaches

This work reviews current theoretical approaches of biophysics and bioinformatics for the description of nucleosome arrangements in chromatin and transcription factor binding to nucleosomal organized DNA. The role of nucleosomes in gene regulation is discussed from molecular-mechanistic and biological point of view. In addition to classical problems of this field, actual questions of epigenetic regulation are discussed. The authors selected for discussion what seem to be the most interesting concepts and hypotheses. Mathematical approaches are described in a simplified language to attract attention to the most important directions of this field

Generating backwashable carbon nanotube mats on the inner surface of polymeric hollow fiber membranes

International audienc

Roll-to-Roll Thin Film Coating on Fluoropolymer Webs - Status, Challenges and Applications

Fluoropolymer webs and membranes commonly exhibit superior optical properties such as high transmittance over a broad wavelength range and very good outdoor stability. Therefore, fluoropolymer films are used in architecture, for example, in membrane roofs and facades in stadiums, shopping malls, and airports or as front-side encapsulation for solar cells. However, thin film deposition on fluoropolymer webs both in vacuum and at atmospheric pressure face several critical challenges including poor mechanical and thermo-mechanical properties, especially low dimensional stability and low elastic modulus, high and textured surface roughness, and low adhesion of thin films. This paper discusses critical process parameters in roll-to-roll processing for both vacuum processes and wet coating processes with respect to the unique properties of fluoropolymer webs. Reactively sputtered oxide layers as well as wet coated ORMOCER (a trademark of the Fraunhofer Institute) layers were deposited on ethylene tetrafluoroethylene (ETFE), polyvinylidene difluoride (PVDF), and ethylene chlorotrifluoroethylene (ECTFE) webs form single and multilayer permeation barrier systems. Layer adhesion and permeation barrier performance was reviewed in relation to the relevant process parameters. Permeation barrier coatings were selected as lead application for this study. Barrier coatings are sensitive to substrate surface irregularities and mechanical damage due to low adhesion, high strain, or roll-to-roll processing issues and therefore were a good measure for the quality of the coating on the substrate. Reactively sputtered zinc-tin oxide (ZTO) layers as well as wet coated ORMOCER (R) layers showed surprisingly good adhesion on both ETFE and PVDF surfaces. Both ZTO and - with adhesion promotion treatment - aluminum oxide (Al2O3) layers have the potential for low water transmission rates (WVTR) below 5 x 10(-2) g/(m(2)d) at 38 degrees C/90 % RH. on these substrates. Further reduction of the WVTR using multilayer stacks was demonstrated with a combination of wet coated ORMOCER layers and sputtered ZTO layers yielding a WVTR of 1 x 10(-3) g/(m(2)d) at 38 degrees C/90 % RH. To achieve that, adapted process parameters and layer stack designs such as reduced web tension and lower layer thicknesses were needed. The potential of the coatings for specific outdoor application is discussed as well as possible ways to improve the polymer web itself to gain a larger process window for roll-to-roll coating on fluoropolymer webs. Demonstrating successful coating on ETFE and PVDF, the results reviewed in this paper potentially enable the use of coated fluoropolymer webs for functionalization of membrane roofs and facades with flexible thin film solar cells, thermal insulation and solar control functionality, flexible thin film electroluminescence, and organic light-emitting diode (OLED) lighting panels as well as electrochromic devices