[Percentile Values for the Anthropometric Dimensions of Triplet Neonates - Analysis of German Perinatal Survey Data of 2007-2011 from all States of Germany]. / Perzentilwerte für die Körpermaße neugeborener Drillinge - Ergebnisse der deutschen Perinatalerhebung der Jahre 2007-2011 unter Beteiligung aller Bundesländer.

AIM: We aimed to develop national reference values for birth weight, length, head circumference, and weight for length for newborn triplets based on data from the German perinatal survey of 2007-2011. MATERIAL AND METHODS: Perinatal survey data of 3,690 newborn triplets from all the states of Germany were kindly provided to us by the AQUA Institute in Göttingen, Germany. Data of 3,567 newborn triplets were included in the analyses. Sex-specific percentile values were calculated using cumulative frequencies. Percentile values at birth were computed for the 3rd, 10th, 25th, 50th, 75th, 90th, and 97th percentiles for 21-36 completed weeks of gestation. RESULTS AND CONCLUSIONS: We present the first German reference values (tables and curves) for the anthropometric dimensions of triplet neonates and compare selected birth weight and length percentiles of triplets (after 32 and 34 completed weeks of gestation) to those of singletons and twins. The differences in the 50th birth weight percentiles between singletons and triplets after 32 completed weeks of gestation were 180 g for girls and 210 g for boys; after 34 weeks of gestation the differences were 320 and 325 g, respectively. The differences between twins and triplets after 32 weeks of gestation were 100 g for girls and 120 g for boys; after 34 weeks of gestation they were 130 and 135 g, respectively. The data presented here enable the classification of newborn triplets according to somatic parameters making reference to German perinatal data.

Exciton size and binding energy limitations in one-dimensional organic materials.

In current organic photovoltaic devices, the loss in energy caused by the charge transfer step necessary for exciton dissociation leads to a low open circuit voltage, being one of the main reasons for rather low power conversion efficiencies. A possible approach to avoid these losses is to tune the exciton binding energy to a value of the order of thermal energy, which would lead to free charges upon absorption of a photon, and therefore increase the power conversion efficiency towards the Shockley-Queisser limit. We determine the size of the excitons for different organic molecules and polymers by time dependent density functional theory calculations. For optically relevant transitions, the exciton size saturates around 0.7 nm for one-dimensional molecules with a size longer than about 4 nm. For the ladder-type polymer poly(benzimidazobenzophenanthroline), we obtain an exciton binding energy of about 0.3 eV, serving as a lower limit of the exciton binding energy for the organic materials investigated. Furthermore, we show that charge transfer transitions increase the exciton size and thus identify possible routes towards a further decrease of the exciton binding energy.

Vibrational modes and changing molecular conformation of perfluororubrene in thin films and solution.

We investigate the vibrational properties of perfluororubrene (PF-RUB) in thin films on silicon wafers with a native oxide layer as well as on silicon wafers covered with a self-assembled monolayer and in dichloromethane solution. In comparison with computed Raman and IR spectra, we can assign the molecular modes and identify two molecular conformations with twisted and planar tetracene backbones of the molecule. Moreover, we employ Raman imaging techniques to study the morphology and distribution of the molecular conformation in PF-RUB thin films.

[Radiation dose in cerebral angiography and flat detector CT applications in neuroradiology]. / Strahlendosis bei zerebraler Angiographie und Flachdetektor-CT-Applikationen in der Neuroradiologie.

Flat detectors (FD) have completely replaced image intensifiers in angiography. Due to this development not only the image quality of 2D digital subtraction angiography series (2-D-DSA) could be improved but also the acquisition of computed tomography (CT)-like cross-sectional images (FD-CT) within the angio suite became feasible. These techniques are now being used in daily clinical routine. Only little information about effective doses of these applications to patients has been published in the literature. We describe the effective patient dose of current applications in the field of angiography and demonstrate strategies to minimize the dose to the patient. In addition, we compare FD-CT applications to standard multislice CT applications.

[Recommendations of the German Society for Rheumatology on the perioperative approach under therapy with DMARDs and biologicals in inflammatory rheumatic diseases]. / Empfehlungen der Deutschen Gesellschaft für Rheumatologie zur perioperativen Vorgehensweise unter Therapie mit DMARD und Biologicals bei entzündlich-rheumatischen Erkrankungen.

BACKGROUND: The perioperative administration of antirheumatic medication can lead to an increased risk of infection and to a malfunction in wound healing up to a manifest infection; however, the termination of antirheumatic therapy can result in a flare up of the disease. Both situations can endanger the success of the operation, particularly in arthroplasty. METHOD: The recommendations have been developed and approved by the Pharmacotherapy Commission of the German Society for Rheumatology following a systematic literature search (as of 30 April 2013) and a consensus process. RESULTS: As very little data with sufficiently high evidence are available, the present recommendations should be considered as having an advisory quality and an individual risk assessment should always be carried out. Classical disease-modifying antirheumatic drugs (DMARD), such as methotrexate can be continued in normal cases but whether this is also true for leflunomide is still undecided. For biologicals a break of two half-life periods before the operation is recommended. The therapy can be continued after wound healing has been completed and when there are no signs of infection.

[New percentile values for the anthropometric dimensions of singleton neonates: analysis of perinatal survey data of 2007-2011 from all 16 states of Germany]. / Neue Perzentilwerte für die Körpermaße neugeborener Einlinge: Ergebnisse der deutschen Perinatalerhebung der Jahre 2007-2011 unter Beteiligung aller 16 Bundesländer.

AIM: The aim of this study was to derive percentile values for birth weight, length, head circumference, and weight for length for singleton neonates based on the German perinatal survey of 2007-2011 (using data from all 16 states of Germany). We also compared these new percentile values with the percentile values of 1995-2000 that so far have been considered standard values. MATERIAL AND METHODS: Data of 3 187 920 singleton neonates from the German perinatal survey of the years 2007-2011 were kindly provided to us by the AQUA Institute in Göttingen, Germany. Sex specific percentile values were calculated using cumulative frequencies. Percentile values at birth were computed for the 3(rd), 10(th), 25(th), 50(th), 75(th), 90(th), and 97(th) percentiles for 21-43 completed weeks of gestation. Percentile curves and tabulated values for the years 2007-2011 were compared with the published values of 1995-2000. RESULTS AND DISCUSSION: Overall the new percentile curves closely resemble the previous ones. Minimal differences can be found for the 10(th) percentile and generally for early weeks of gestation. Values for the 10(th) percentile in the 2007-2011 dataset are somewhat higher than values of 1995-2000 for birth weight, length, and weight for length. CONCLUSIONS: We recommend the use of these new percentile values instead of the old ones.

[New percentile values for the anthropometric dimensions of twin neonates: analysis of perinatal survey data of 2007-2011 from all 16 states of Germany]. / Neue Perzentilwerte für die Körpermaße neugeborener Zwillinge: Ergebnisse der deutschen Perinatalerhebung der Jahre 2007-2011 unter Beteiligung aller 16 Bundesländer.

AIM: The aim of this study was to develop new national standards for birth weight, length, head circumference, and weight for length for newborn twins based on the German perinatal survey of 2007-2011. We also assessed trends in anthropometric measurements by comparing these new percentile values with the percentile values of 1990-1994. MATERIAL AND METHODS: Perinatal survey data of 110,313 newborn twins from all the states of Germany collected in the years 2007-2011 were kindly provided by the AQUA Institute in Göttingen, Germany. Sex specific percentile values were calculated using cumulative frequencies. Percentile values at birth were computed for the 3rd, 10th, 25th, 50th, 75th, 90th, and 97th percentiles for 21-40 completed weeks of gestation. Percentile curves and tabulated values for the years 2007-2011 were compared with the published values of 1990-1994. RESULTS AND DISCUSSION: The new percentile curves (2007-2011) closely resemble the previous ones (1990-1994). Small differences can nonetheless be found. For example, for birth weight the new values for the 10th percentile are a little higher. CONCLUSIONS: We recommend using the new percentile values instead of the old ones.

Quantitative allocation of Bragg scattering effects in highly efficient OLEDs fabricated on periodically corrugated substrates.

Bragg scattering effects in bottom-emitting organic light-emitting diodes (OLEDs) grown on corrugated aluminum-doped zinc oxide electrodes are analyzed. Periodic corrugation is introduced by structuring the oxide electrode via UV laser ablation, a process that enables flexible adjustment of the period and height of corrugation. We demonstrate that fabrication of stable and electrically efficient OLEDs on these rough substrates is feasible. Sharp spectral features are superimposed onto the broad emission spectra of the OLEDs, providing clear evidence for Bragg scattering of light from guided modes into the air cone. Theoretical analysis based on an emissive dipole model and conservation of momentum considerations allows a quantitative description of scattering and the associated dispersion relations.

Self-heating, bistability, and thermal switching in organic semiconductors.

We demonstrate electric bistability induced by the positive feedback of self-heating onto the thermally activated conductivity in a two-terminal device based on the organic semiconductor C(60). The central undoped layer with a thickness of 300 nm is embedded between thinner n-doped layers adjacent to the contacts, minimizing injection barriers. The observed current-voltage characteristics follow the general theory for thermistors described by an Arrhenius-like conductivity law. Our findings include hysteresis phenomena and are of general relevance for the entire material class since most organic semiconductors can be described by a thermally activated conductivity.

Analysis of the German perinatal survey of the years 2007-2011 and comparison with data from 1995-1997: neonatal characteristics and duration of pregnancy.

BACKGROUND AND AIM: We have previously analysed neonatal characteristics and duration of pregnancy in Germany based on data from the German Perinatal Survey of 1995-1997. Here we describe neonatal characteristics and duration of pregnancy based on the German Perinatal Survey of 2007-2011. MATERIAL AND METHODS: We had been provided with data from the German Perinatal Survey of 1995-1997 by the chambers of physicians of all the states of Germany except Baden-Württemberg (1 815 318 singleton neonates). We were also provided with access to the perinatal survey data of 2007-2011 by the AQUA Institute in Göttingen, Germany (3 187 920 singleton neonates). We investigated regional differences within Germany and also compared the 2 periods of time. We used the computer programme SPSS for data analysis and performed plausibility checks on the survey data. RESULTS: Comparing the states of Germany, we found that birth weight was largest for neonates born in Schleswig-Holstein (3 407 g) and Mecklenburg-Western Pomerania (3 392 g); the lowest mean birth weight was observed in the Saarland (3 283 g). Preterm birth rate varied between 6.3% (Saxony) and 8.1% (Bremen, Saarland). Comparing 1995-1997 vs. 2007-2011, deliveries after 37 and 38 weeks of gestation were more common and deliveries after 39 and more weeks of gestation were less common in the later period of time. CONCLUSIONS: Regional differences in the anthropometric characteristics of neonates exist between the states of Germany. The proportion of deliveries after 39 and more weeks of gestation has decreased.

Collecting close-contact social mixing data with contact diaries: reporting errors and biases.

The analysis of contact networks plays a major role to understanding the dynamics of disease spread. Empirical contact data is often collected using contact diaries. Such studies rely on self-reported perceptions of contacts, and arrangements for validation are usually not made. Our study was based on a complete network study design that allowed for the analysis of reporting accuracy in contact diary studies. We collected contact data of the employees of three research groups over a period of 1 work week. We found that more than one third of all reported contacts were only reported by one out of the two involved contact partners. Non-reporting is most frequent in cases of short, non-intense contact. We estimated that the probability of forgetting a contact of ≤5 min duration is greater than 50%. Furthermore, the number of forgotten contacts appears to be proportional to the total number of contacts.

Photoluminescence spectroscopy of pure pentacene, perfluoropentacene, and mixed thin films.

We report detailed temperature dependent photoluminescence (PL) spectra of pentacene (PEN), perfluoropentacene (PFP), and PEN:PFP mixed thin films grown on SiO(2). PEN and PFP are particularly suitable for this study, since they are structurally compatible for good intermixing and form a model donor/acceptor system. The PL spectra of PEN are discussed in the context of existing literature and compared to the new findings for PFP. We analyze the optical transitions observed in the spectra of PEN and PFP using time-dependent density functional theory calculations. Importantly, for the mixed PEN:PFP film we observe an optical transition in PL at 1.4 eV providing evidence for coupling effects in the blend. We discuss a possible charge-transfer (CT) and provide a tentative scheme of the optical transitions in the blended films.

Resonant Raman spectra of diindenoperylene thin films.

Resonant and preresonant Raman spectra obtained on diindenoperylene (DIP) thin films are interpreted with calculations of the deformation of a relaxed excited molecule with density functional theory (DFT). The comparison of excited state geometries based on time-dependent DFT or on a constrained DFT scheme with observed absorption spectra of dissolved DIP reveals that the deformation pattern deduced from constrained DFT is more reliable. Most observed Raman peaks can be assigned to calculated A(g)-symmetric breathing modes of DIP or their combinations. As the position of one of the laser lines used falls into a highly structured absorption band, we have carefully analyzed the Raman excitation profile arising from the frequency dependence of the dielectric tensor. This procedure gives Raman cross sections in good agreement with the observed relative intensities, both in the fully resonant and in the preresonant case.

Real-time changes in the optical spectrum of organic semiconducting films and their thickness regimes during growth.

We present real-time in situ studies of optical spectra during thin film growth of several prototype organic semiconductors (pentacene, perfluoropentacene, and diindenoperylene) on SiO2. These data provide insight into surface and interface effects that are of fundamental importance and of relevance for applications in organic electronics. With respect to the bulk, the different molecular environment and structural changes within the first few monolayers can give rise to significant optical changes. Similar to interface-driven phenomena in, e.g., magnetism, spectral changes as a function of thickness d are a very general effect, decaying as 1/d in the simplest approximation. We observe energy shifts of 50-100 meV, rather small changes of the exciton-phonon coupling, and new transitions in specific systems, which should be considered as general features of the growth of organics.

Nanoscale spectroscopic imaging of organic semiconductor films by plasmon-polariton coupling.

Tip-enhanced near-field optical images and correlated topographic images of an organic semiconductor film (diindenoperylene, DIP) on Si have been recorded with high optical contrast and high spatial resolution (17 nm) using a parabolic mirror with a high numerical aperture for tip illumination and signal collection. The DIP molecular domain boundaries being one to four molecular layers (1.5-6 nm) high are resolved topographically by a shear-force scanning tip and optically by simultaneously recording the 6x10{5} times enhanced photoluminescence (PL). The excitation is 4x10{4} times enhanced and the intrinsically weak PL-yield of the DIP-film is 15-fold enhanced by the tip. The Raman spectra indicate an upright orientation of the DIP molecules. The enhanced PL contrast results from the local film morphology via stronger coupling between the tip plasmon and the exciton-polariton in the DIP film.

[Pitfalls and difficulties in interpretation of bone densitometry]. / Fehlermöglichkeiten und Interpretationsprobleme der Osteodensitometrie.

The clinical relevance of osteoporosis as a frequent systemic skeletal disease is to be found in fractures and their consequences. For prevention of these disease manifestations great importance must be attached to a safest possible diagnosis even before the occurrence of the first fracture and osteodensitometry is a well established technique for this purpose. Among the different measurement procedures DXA (dual-energy X-ray absorptiometry) has become the gold standard worldwide. This method is seen as very reliable and adequately precise. Prerequisites for these characteristics are the correct interpretation of the measurement data obtained by taking into consideration all potential influencing factors which can either false positively or false negatively influence a single value as well as the calculated mean value and the T and Z scores. Thus, exact knowledge of potential sources of error is of crucial importance. The present study shows important sources of error and difficulties in interpretation as well as a discussion of the options for their prevention. For the clinical practice osteodensitometry is to be seen as an important diagnostic component, which can only been interpreted meaningfully with respect to the clinical data.

Silicon nanowire oxidation: the influence of sidewall structure and gold distribution.

The oxidation behavior of Si nanowires (SiNWs) grown by the gold (Au) catalyzed vapor-liquid-solid (VLS) growth process in an electron beam evaporation (EBE) reactor is studied. The VLS SiNWs exhibit hexagonal shape with essentially {112} facets where each facet shows a saw-tooth faceting itself, consisting of alternating {111} and {113} facets. Depending on growth temperatures (450-750 degrees C) and evaporation currents (40-80 mA) that determine the silicon vapor supply, this facet formation is more or less pronounced. The diffusion of Au atoms on the faceted SiNW surfaces and the formation of Au nanoparticles on the SiNW facets during growth and during ex situ annealing are studied. Upon diffusion, the Au atoms agglomerate and form Au nanoparticles that preferably arrange themselves on {113} facets. Upon annealing in air at temperatures between 800 and 950 degrees C the gold nanoparticles agglomerate further and form bigger particles of a few tens of nm in diameter that reside at the interface between the growing silica (SiO(2)) layer and the SiNW itself, which in turn shrinks during SiNW oxidation. The oxide layer thickness and the oxide appearance depend on the annealing conditions (time and temperature) and systematically varied oxidation processing is described in this paper as investigated by cross-sectional transmission electron microscopy (TEM) including high resolution studies as well as scanning electron microscopy (SEM) studies. Our results strongly suggest that the SiNWs can be fully oxidized, thus forming silica NWs that can either keep their initial shape or, under certain annealing conditions, do not keep their initial wire shape but assume a bamboo-like shape that forms most likely as a result of locally high stresses that are related to nanocrack formation. The nanocracks form in the growing oxide layer mediated by the presence of Au nanoparticles that yield gold-enhanced SiNW oxidation and thus a faster oxidation rate.

Optical spectra obtained from amorphous films of rubrene: Evidence for predominance of twisted isomer.

In order to investigate the optical properties of rubrene we study the vibronic progression of the first absorption band (lowest pi-->pi( *) transition). We analyze the dielectric function epsilon(2) of rubrene in solution and thin films using the displaced harmonic oscillator model and derive all relevant parameters of the vibronic progression. The findings are supplemented by density functional calculations using B3LYP hybrid functionals. Our theoretical results for the molecule in two different conformations, i.e., with a twisted or planar tetracene backbone, are in very good agreement with the experimental data obtained for rubrene in solution and thin films. Moreover, a simulation based on the monomer spectrum and the calculated transition energies of the two conformations indicates that the thin film spectrum of rubrene is dominated by the twisted isomer.

S(1)<--S(0) transition of 2,3-benzofluorene at low temperatures in the gas phase.

The S(1)((1)A('))<--S(0)((1)A(')) absorption spectrum of jet-cooled 2,3-benzofluorene (Bzf) has been measured by cavity ring-down spectroscopy. The potential energy surfaces of the S(n=0,1,2) states of Bzf have been investigated with calculations based on the time-dependent density functional theory (TD-DFT). At the B3LYP/TZ level of theory, TD-DFT does not deliver a realistic difference between the excited S(1) and S(2) potential energy surfaces, a problem which can be avoided by introducing a reference geometry where this difference coincides with the observation. In this geometry, an expression for the Herzberg-Teller corrected intensities of the vibronic bands is proposed, allowing a straightforward assignment of the observed a(') modes below 900 cm(-1), including realistic calculated intensities. For vibronic bands at higher energies, the agreement between calculated and observed modes is deteriorated by substantial Dushinsky rotations and nonparabolicities of the potential energy surface S(1).