bluuebunny/crossref_metadata_2025 huggingface dataset:
Körperliche Beschwerden bei älteren Migranten in Deutschland 1Erstellt unter Mitwirkung der Arbeitsgruppe «Abuse of the Elderly in the European Region» (ABUEL): Joaquim F. J. Soares, Department of Public Health Sciences, Karolinska Institute, Stockholm, Sweden; Francisco Torres-González, Departmental Section of Psychiatry and Psychological Medicine, University of Granada, Spain; Elisabeth Ioannidi-Kapolou, National School of Public Health, Department of Sociology, Athens, Greece; Giovanni Lamura, Italian National Research Centre on Ageing Department of Gerontological Research, Unit of Health Economics, Ancona, Italy; Mindaugas Stankunas, Kaunas University of Medicine, Department of Health Management, A. Mickeviciaus, Kaunas, Lithuania; Henrique Barros, Department of Hygiene and Epidemiology, University of Porto Medical School, Porto, Portugal.
Authors: Csöff Rosina-Martha , Macassa Gloria , Lindert Jutta
Published: July 2010

Körperliche Beschwerden sind bei Älteren weit verbreitet; diese sind bei Migranten bislang in Deutschland und international noch wenig untersucht. Unsere multizentrische Querschnittstudie erfasste körperliche Beschwerden bei Menschen im Alter zwischen 60 und 84 Jahren mit Wohnsitz in Stuttgart anhand der Kurzversion des Gießener Beschwerdebogens (GBB-24). In Deutschland wurden 648 Personen untersucht, davon 13.4 % (n = 87) nicht in Deutschland geborene. Die Geschlechterverteilung war bei Migranten und Nichtmigranten gleich; der sozioökonomische Status lag bei den Migranten etwas niedriger: 8.0 % (n = 7) der Migranten und 2.5 % (n = 14) der Nichtmigranten verfügten über höchstens vier Jahre Schulbildung; 12.6 % (n = 11) der Migranten und 8.2 % (n = 46) der Nichtmigranten hatten ein monatliches Haushaltsnettoeinkommen von unter 1000€; 26.4 % der Migranten und 38.1 % (n = 214) der Nichtmigranten verfügten über mehr als 2000€ monatlich. Somatische Beschwerden lagen bei den Migranten bei 65.5 % (n = 57) und bei den Nichtmigranten bei 55.8 % (n = 313). Frauen wiesen häufiger somatische Beschwerden auf (61.8 %) als Männer (51.8 %). Mit steigendem Alter nahmen somatische Beschwerden zu. Mit Ausnahme der Altersgruppe der 70–74-Jährigen konnte kein signifikanter Unterschied zwischen Migranten und Nichtmigranten hinsichtlich der Häufigkeit körperlicher Beschwerden gezeigt werden. Ausblick: Es werden dringend bevölkerungsrepräsentative Studien zu körperlichen Beschwerden bei Migranten benötigt.
Längerfristige Effekte des JobFit-Trainings für Jugendliche
Authors: Koglin Ute , Petermann Franz , Heffter Philipp , Petermann Ulrike
Published: July 2010

Die quasi-experimentelle Studie untersucht die Wirksamkeit des schulbasierten JobFit-Trainings unmittelbar nach Abschluss des Programms und sechs Monate später. Es nahmen 104 Gesamtschüler im Alter zwischen 13;2 und 17;3 Jahren an der Studie teil. Es wurde überprüft, ob die Jugendlichen der Interventionsgruppe (n = 60) durch das Programm ihre sozialen Kompetenzen verbessern und Verhaltensprobleme aus Sicht der Lehrkräfte abgebaut werden konnten. Varianzanalysen (MANOVA, ANCOVA, ANOVA) mit den Werten des Strengths and Difficulties Questionnaire (SDQ-L) ergaben signifikante Unterschiede zwischen den Gruppen auf den Subskalen «Emotionale Probleme», «Verhaltensprobleme», «Prosoziales Verhalten» und «Gesamtproblemwert». Die Effektstärken (post-prä) der Gruppenunterschiede variieren zwischen d = .46 und d = .86 und entsprechen den Effekten ähnlicher angloamerikanischer Programme für das Jugendalter.
Degenerative Gelenkerkrankungen – welche Therapie ist evidenzbasiert?
Authors: Rosemann  , Huber  , Rosemann
Published: July 2010

Das Medikament der ersten Wahl in der Therapie der Arthrose ist Paracetamol. NSAR sind etwas stärker analgetisch wirksam und besitzen zudem eine antiphlogistische Komponente, ihr Einsatz sollte jedoch zeitlich immer eng begrenzt sein und der akuten, dekompensierten Arthritis vorbehalten bleiben. Diclofenac bleibt hier das Mittel der Wahl. Bei Patienten mit einem erhöhten gastrointestinalen Risiko sollte eine Kombinationstherapie aus einem tNSAR und einem Protonenpumpenhemmer erfolgen. Bei Patienten mit kardiovaskulären Risikofaktoren sollten sie nur nach strengster Indikationsstellung zum Einsatz kommen. Opioide haben bei kritischer Indikationsstellung ihre berechtigte Stellung in der Arthrosetherapie. Sie sollten Bestandteil eines Schmerzregimes sein, das ein Schmerztagebuch und regelmässige Reevaluationen beinhaltet. Wichtig ist es, die Bedeutung der körperlichen Aktivität für die Gelenkfunktion und die Gewichtskontrolle deutlich zu machen.
Positive First or Negative First?
Authors: Krebs Dagmar , Hoffmeyer-Zlotnik Juergen H.P.
Published: July 2010

To examine whether starting a response scale with the positive or the negative categories affects response behavior, a split-ballot design using reverse forms of an 8-point scale assessing the subjective importance of job characteristics was used. Response behavior varied according to the scale format employed. Responses were more positive on the scale starting with the category “very important” (split 2). By contrast, the scale starting with the category “not at all important” (split 1) did not elicit more negative responses, but rather less positive ones. However, differences in response behavior did not systematically reflect the direction of the respective scales. Starting with the differences between the two split versions, the factorial structure of indicators assessing two dimensions of job motivation was tested for each scale type separately and then for both scale types simultaneously. Finally, models placing increasingly severe equality constraints on both scale types were tested. The paper concludes with a discussion of the results and desiderata for further research.
Experimental Vignette Studies in Survey Research
Authors: Atzmüller Christiane , Steiner Peter M.
Published: July 2010

Vignette studies use short descriptions of situations or persons (vignettes) that are usually shown to respondents within surveys in order to elicit their judgments about these scenarios. By systematically varying the levels of theoretically important vignette characteristics a large population of different vignettes is typically available – too large to be presented to each respondent. Therefore, each respondent gets only a subset of vignettes. These subsets may either be randomly selected in following the tradition of the factorial survey or systematically selected according to an experimental design. We show that these strategies in selecting vignette sets have strong implications for the analysis and interpretation of vignette data. Random selection strategies result in a random confounding of effects and heavily rely on the assumption of no interaction effects. In contrast, experimental strategies systematically confound interaction effects with main or set effects, thereby preserving a meaningful interpretation of main and important interaction effects. Using a pilot study on attitudes toward immigrants we demonstrate the implementation and analysis of a confounded factorial design.
A hybrid radial basis function–pseudospectral method for thermal convection in a 3‐D spherical shell
Authors: Wright G. B. , Flyer N. , Yuen D. A.
Published: July 2010

A novel hybrid spectral method that combines radial basis function (RBF) and Chebyshev pseudospectral methods in a “2 + 1” approach is presented for numerically simulating thermal convection in a 3‐D spherical shell. This is the first study to apply RBFs to a full 3‐D physical model in spherical geometry. In addition to being spectrally accurate, RBFs are not defined in terms of any surface‐based coordinate system such as spherical coordinates. As a result, when used in the lateral directions, as in this study, they completely circumvent the pole issue with the further advantage that nodes can be “scattered” over the surface of a sphere. In the radial direction, Chebyshev polynomials are used, which are also spectrally accurate and provide the necessary clustering near the boundaries to resolve boundary layers. Applications of this new hybrid methodology are given to the problem of convection in the Earth's mantle, which is modeled by a Boussinesq fluid at infinite Prandtl number. To see whether this numerical technique warrants further investigation, the study limits itself to an isoviscous mantle. Benchmark comparisons are presented with other currently used mantle convection codes for Rayleigh number (Ra) 7 × 103 and 105. Results from a Ra = 106 simulation are also given. The algorithmic simplicity of the code (mostly due to RBFs) allows it to be written in less than 400 lines of MATLAB and run on a single workstation. We find that our method is very competitive with those currently used in the literature.
Polar mesospheric cloud structures observed from the cloud imaging and particle size experiment on the Aeronomy of Ice in the Mesosphere spacecraft: Atmospheric gravity waves as drivers for longitudinal variability in polar mesospheric cloud occurrence
Authors: Chandran A. , Rusch D. W. , Merkel A. W. , Palo S. E. , Thomas G. E. , Taylor M. J. , Bailey S. M. , Russell J. M.
Published: July 2010

The cloud imaging and particle size (CIPS) experiment is one of three instruments on board the Aeronomy of Ice in the Mesosphere (AIM) spacecraft that was launched into a 600 km Sun‐synchronous orbit on 25 April 2007. CIPS images have shown distinct wave patterns and structures in polar mesospheric clouds (PMCs), around the summertime mesopause region, which are qualitatively similar to structures seen in noctilucent clouds (NLCs) from ground‐based photographs. The structures in PMC are generally considered to be manifestations of upward propagating atmospheric gravity waves (AGWs). Variability of AGW effects on PMC reported at several lidar sites has led to the notion of longitudinal differences in this relationship. This study compares the longitudinal variability in the CIPS‐observed wave occurrence frequency with CIPS‐measured PMC occurrence frequency and albedo along with mesospheric temperatures measured by the sounding of the atmosphere using broadband emission radiometry instrument on board the Thermosphere Ionosphere Mesosphere Energetics and Dynamics spacecraft. Our results for the latitude ranges between 70° and 80° show a distinct anticorrelation of wave structures with cloud occurrence frequency and correlations with temperature perturbations for at least two of the four seasons analyzed, supporting the idea of gravity wave‐induced cloud sublimation. The locations of the observed wave events show regions of high wave activity in both hemispheres. In the Northern Hemisphere, while the longitudinal variability in observed wave structures show changes from the 2007–2008 seasons, there exist regions of both low and high wave activities common to the two seasons. These persistent features may explain some of the observed differences in PMC activity reported by ground‐based lidar instruments distributed at different longitudes. The statistical distribution of horizontal scales increases with wavelength up to at least 250 km. We also discuss the possibility of atmospheric tides, especially the nonmigrating semidiurnal tide, aliasing our observations and affecting the results presented in this analysis.
Seasonal and interannual variability of gravity wave activity revealed by long‐term lidar observations over Mauna Loa Observatory, Hawaii
Authors: Li Tao , Leblanc Thierry , McDermid I. Stuart , Wu Dong L. , Dou Xiankang , Wang Shui
Published: July 2010

The seasonal and interannual variability of gravity wave (GW) variance in the upper stratosphere (35–50 km) and lower mesosphere (48–63 km) has been studied using 10.5 years (January 1997 to June 2007) of temperature profile results obtained with the Jet Propulsion Laboratory Rayleigh lidar at Mauna Loa Observatory, Hawaii (19.5°N, 155.6°W). Seasonal variability with a maximum in winter and a minimum in summer was observed in the upper stratosphere, suggesting dominance of the annual oscillation. In the lower mesosphere the seasonal oscillations of GW variance were dominated by a semiannual oscillation (SAO), likely due to the selective filtering of GWs by the tropical upper stratospheric SAO wind. Modulation of GW variance by the quasi‐biennial oscillation was clearly present only for the long vertical wavelength band in the upper stratosphere, and not in the lower mesosphere. The United Kingdom Met Office zonal mean zonal wind further supports that enhanced GW activity in the upper stratosphere corresponds to the westerly shear phase of the zonal wind at 10 hPa (∼30 km), and suppressed activity corresponds to the easterly shear phase. During the strong El Niño event in the winter of 1997–1998, enhanced GW activity was observed only in the lower mesosphere, and not in the upper stratosphere. Additional enhancement of GW variance, especially clear in the upper stratosphere, was also found during 2001–2002 and winter 2005–2006.
Non‐Fourier thermal transport in fractured geological media
Authors: Geiger Sebastian , Emmanuel Simon
Published: July 2010

In a similar way to solute transport, heat transfer in porous media is governed by advection and dispersion processes, and “non‐Fourier” behavior, characterized by early breakthrough and long tailing, might also be expected to occur. While “non‐Fickian” solute transport has been studied extensively and an effective mathematical framework (the Continuous Time Random Walk (CTRW)) has been developed to describe it, there has been little experimental or numerical investigation of non‐Fourier thermal transfer in porous media. As a result of different transfer rates for heat and solute transport, it is unclear if non‐Fourier may occur or when it can be adequately modeled by an advection‐diffusion equation. We conducted high‐resolution finite element–finite volume numerical simulations of heat transfer in two geologically realistic fractured porous domains. We calculated thermal breakthrough curves at various locations in the domains and analyzed them with a CTRW model adapted for heat transfer. Our analysis shows that heat transport in the first, well‐connected fracture network is Fourier‐like, even though the thermal front is highly irregular. Consequently, it can be modeled by an advection‐diffusion equation using macroscopic dispersivities. By contrast, heat transport in the second, poorly connected fracture pattern is highly non‐Fourier. Hence, the classical advection‐diffusion equation is unable to capture the main features, but they can be modeled successfully by CTRW. The occurrence of non‐Fourier behavior has important implications for a range of processes including geothermal reservoir engineering, radioactive waste storage, and enhanced oil recovery.
Energetic neutral atoms from the Earth's subsolar magnetopause
Authors: Fuselier S. A. , Funsten H. O. , Heirtzler D. , Janzen P. , Kucharek H. , McComas D. J. , Möbius E. , Moore T. E. , Petrinec S. M. , Reisenfeld D. B. , Schwadron N. A. , Trattner K. J. , Wurz P.
Published: July 2010

The shocked solar wind in the Earth's magnetosheath becomes nearly stationary at the subsolar magnetopause. At this location, solar wind protons are neutralized by charge exchange with neutral hydrogen atoms at the extreme limits of the Earth's tenuous exosphere. The resulting Energetic Neutral Atoms (ENAs) propagate away from the subsolar region in nearly all directions. Simultaneous observations of hydrogen ENAs from the Interstellar Boundary Explorer (IBEX) and proton distributions in the magnetosheath from the Cluster spacecraft are used to quantify this charge exchange process. By combining these observations with a relatively simple model, estimates are obtained for the ratio of ENA to shocked solar wind flux (about 10−4) and the exospheric density at distances greater than 10 Earth Radii (RE) upstream from the Earth (about 8 cm−3).
Comparison of Immortalized bEnd5 and Primary Mouse Brain Microvascular Endothelial Cells as in vitro Blood–Brain Barrier Models for the Study of T Cell Extravasation
Authors: Steiner Oliver , Coisne Caroline , Engelhardt Britta , Lyck Ruth
Published: July 2010

Important insights into the molecular mechanism of T cell extravasation across the blood–brain barrier (BBB) have already been obtained using immortalized mouse brain endothelioma cell lines (bEnd). However, compared with bEnd, primary brain endothelial cells have been shown to establish better barrier characteristics, including complex tight junctions and low permeability. In this study, we asked whether bEnd5 and primary mouse brain microvascular endothelial cells (pMBMECs) were equally suited as in vitro models with which to study the cellular and molecular mechanisms of T cell extravasation across the BBB. We found that both in vitro BBB models equally supported both T cell adhesion under static and physiologic flow conditions, and T cell crawling on the endothelial surface against the direction of flow. In contrast, distances of T cell crawling on pMBMECs were strikingly longer than on bEnd5, whereas diapedesis of T cells across pMBMECs was dramatically reduced compared with bEnd5. Thus, both in vitro BBB models are suited to study T cell adhesion. However, because pMBMECs better reflect endothelial BBB specialization in vivo, we propose that more reliable information about the cellular and molecular mechanisms of T cell diapedesis across the BBB can be attained using pMBMECs.
Comprehension of the Communicative Intent Behind Pointing and Gazing Gestures by Young Children with Williams Syndrome or Down Syndrome
Authors: John Angela E. , Mervis Carolyn B.
Published: July 2010

Purpose

In this study, the authors examined the ability of preschoolers with Williams syndrome (WS) or Down syndrome (DS) to infer communicative intent as expressed through gestures (pointing and eye-gaze shift).

Method

Participants were given a communicative or noncommunicative cue involving pointing or gaze shifting in the context of a hiding game. Each child completed 4 conditions formed by crossing Communicative Style (communicative vs. noncommunicative) and Gesture (point vs. gaze shift).

Results

At the group level, children in both groups located the toy significantly more often than expected by chance in the communicative condition but performed at chance in the noncommunicative condition. Children in both groups were more likely to infer communicative intent when pointing rather than gaze shifting was used. Individually, despite significantly lower developmental quotient and language standard scores, significantly more children with DS than with WS successfully used the experimenter’s communicative gestures.

Conclusions

At the group level, preschoolers with WS or DS were able to comprehend the communicative intent expressed by pointing and gazing gestures in a tabletop task. Children with DS evidenced significantly stronger pragmatic skills than did children with WS, providing further evidence that children with WS have more difficulty with sociocommunication than expected for chronological age or cognitive/language ability.
The Effects of Literate Narrative Intervention on Children With Neurologically Based Language Impairments: An Early Stage Study
Authors: Petersen Douglas B. , Gillam Sandra Laing , Spencer Trina , Gillam Ronald B.
Published: July 2010

Purpose

This study investigated the effect of a literate narrative intervention on the macrostructural and microstructural language features of the oral narratives of 3 children with neuromuscular impairment and co-morbid receptive and expressive language impairment.

Method

Three children, ages 6-8 years, participated in a multiple baseline across participants and language features study. The 3 participants engaged in 10 individual literate narrative intervention sessions following staggered baseline trials. Assessment probes eliciting picture- and verbally prompted narratives were recorded and analyzed.

Results

All three children demonstrated gains in the use of story grammar (macrostructure) and causality (microstructure), with moderate to large effect sizes based on percentage of nonoverlapping data points. Gains were seen in both picture-prompted narratives that were the direct focus of intervention and in verbally prompted narratives that served as a measure of generalization. Other features of microstructure not explicitly targeted during intervention increased in the narratives produced by the participants. Additionally, follow-up data collected 8 months after intervention indicated the maintenance of some skills over time.

Conclusion

The results of this study suggest that literate narrative intervention may be useful for improving children’s functional use of narrative macrostructure and microstructure, including literate language.
Types of Parent Verbal Responsiveness That Predict Language in Young Children With Autism Spectrum Disorder
Authors: McDuffie Andrea , Yoder Paul
Published: July 2010

Purpose

This study examined short-term predictive associations between 5 different types of parent verbal responsiveness and later spoken vocabulary for 32 young children with a confirmed diagnosis of autism spectrum disorder (ASD).

Method

Parent verbal utterances were coded from videotapes of naturalistic parent–child play sessions using interval and event-based coding. A vocabulary difference score, calculated using the MacArthur Communicative Development Inventories (L. Fenson et al., 1993), was used as the outcome measure of spoken vocabulary 6 months later.

Results

Parent follow-in comments and follow-in directives predicted spoken vocabulary after controlling for child engagement. Parent expansions of child verbal utterances predicted spoken vocabulary after controlling for child talkativeness. When entered together into a regression analysis, metrics that represented (a) the number of parent utterances following into the child’s focus of attention and (b) the number of parent utterances responding to child verbal communication acts both accounted for unique variance in predicting change in spoken vocabulary from Time 1 to Time 2.

Conclusion

Parent verbal utterances that follow into the child’s current focus of attention or respond to child verbal communication acts may facilitate the process of early vocabulary acquisition by mitigating the need for children with ASD to use attention-following as a word-learning strategy.
Role of Linguistic Input in Third Person Singular –
s
Use in the Speech of Young Children
Authors: Finneran Denise A. , Leonard Laurence B.
Published: July 2010

Purpose

To examine the role of linguistic input in how young, typically developing children use the 3rd person singular –
s
(3S) inflection.

Method

Novel verbs were presented to 16 young children in either 3S contexts (e.g., “The tiger heens”) or nonfinite (NF) contexts (e.g., “Will the tiger heen?”). The input was further manipulated for length such that half of the presentations in each context had adjectives modifying the subject. Children were then prompted to use the novel verbs in contexts requiring 3S and in contexts requiring an infinitive form. The children’s use of 3S with familiar verbs was also examined.

Results

Novel verbs heard only in 3S contexts were more likely to be produced with 3S in obligatory contexts and were more likely to be inappropriately applied to infinitive contexts than novel verbs heard only in NF contexts. Degree of 3S use in obligatory contexts was lower for familiar verbs than for novel verbs heard only in 3S contexts but higher than for novel verbs heard only in NF contexts. Length was not a significant factor.

Conclusion

Linguistic input appears to have a strong effect on how young children use the 3S inflection in newly encountered verbs.
What biogeography is: a place for process
Authors: McDowall R. M.
Published: July 2010

The search for understanding of the past and present processes that have and/or continue to generate observed biotic distribution patterns substantially involves historical reconstruction based on present patterns (both phylogenetic and geographical). How this should be undertaken has been a cause for major debate over many decades. Residual patterns do not always provide explicit pointers to the causal processes, and in addition to applying our understanding of earth history, we need also to carefully explore the implications of contemporary processes as a means for unravelling pattern. Some biogeographers assert that earth and life evolve together, but knowledge of distributions and ecologies indicate that this is sometimes true and sometimes false. Just as general patterns may sometimes indicate a commonality of the means that generated the patterns so, too, do observable processes sometimes indicate commonalities. Vicariance and dispersal are fundamental attributes of biotic distributions. Phylogeography has the potential to assist us in determining which of these mechanisms has generated observable patterns.
Enhancing exposure depth for surface-plasmon polaritons interference nanolithography by waveguide modulation
Authors: Wang Jing-Quan , Liang Hui-Min , Niu Xiao-Yun , Du Jing-Lei , Ye Song , Zhang Zhi-You
Published: July 2010

A maskless interference device with a waveguide coated thin metal film is investigated for surface-plasmon polaritons interference lithography (SPPIL) in this paper. The focal depth of interference fringes in the resist is modulated obviously by the thicknesses of the waveguide and the metal film, which will solve the question of short exposure depth for conventional SPPIL, and improve the practicability of SPPIL. Simulated and analyzed results demonstrated that the focal depth of interference fringes is increased dramatically with suitable parameters for the structure.
Experimental and theoretical investigation on polarization reversal in unfatigued lead-zirconate-titanate ceramic
Authors: Zhukov Sergey , Genenko Yuri A. , von Seggern Heinz
Published: July 2010

The dynamics of polarization switching in a soft lead-zirconate-titanate ceramic has been studied over a broad time window ranging from 10−6–106 for applied fields between 0.5 and 2.5 kV/mm. The classical Kolmogorov–Avrami–Ishibashi model of the polarization reversal was not able to satisfactory explain the obtained results. Therefore, a new concept for the polarization dynamics of ferroelectric ceramics has been suggested, which is based on two principal assumptions, (1) a strong dependence of the polarization switching time on the local electric field and (2) a random distribution of the local switching times caused by an intrinsic randomness in the field distribution within the system. Thereby the switching volume is composed as an ensemble of many regions with independent dynamics governed by local field exclusively. Such random field distribution could be well adjusted by a Gaussian distribution around the mean value of the field applied. A total polarization dependence on time and applied field was obtained in explicit form with only three fitting parameters which enabled a good description of the experimental results on polarization reversal in the whole time-field domain.
Temperature dependence of vibrational frequency fluctuation of N3− in D2O
Authors: Tayama Jumpei , Ishihara Akane , Banno Motohiro , Ohta Kaoru , Saito Shinji , Tominaga Keisuke
Published: July 2010

We have studied the temperature dependence of the vibrational frequency fluctuation of the antisymmetric stretching mode of N3− in D2O by three-pulse infrared (IR) photon echo experiments. IR pump-probe measurements were also carried out to investigate the population relaxation and the orientational relaxation of the same band. It was found that the time-correlation function (TCF) of the frequency fluctuation of this mode is well described by a biexponential function with a quasistatic term. The faster decay component has a time constant of about 0.1 ps, and the slower component varies from 1.4 to 1.1 ps in the temperature range from 283 to 353 K. This result indicates that liquid dynamics related to the frequency fluctuation are not highly sensitive to temperature. We discuss the relationship between the temperature dependence of the vibrational frequency fluctuation and that of the molecular motion of the system to investigate the molecular origin of the frequency fluctuation of the solute. We compare the temperature dependence of the frequency fluctuation with that of other dynamics such as dielectric relaxation of water. In contrast to the Debye dielectric relaxation time of D2O, the two time constants of the TCF of the frequency fluctuation do not exhibit strong temperature dependence. We propose a simple theoretical model for the frequency fluctuation in solutions based on perturbation theory and the dipole-dipole interaction between the vibrational mode of the solute and the solvent molecules. This model suggests that the neighboring solvent molecules in the vicinity of the solute play an important role in the frequency fluctuation. We suggest that the picosecond component of the frequency fluctuation results from structural fluctuation of the hydrogen-bonding network in water.
Hydrogen bond, electron donor-acceptor dimer, and residence dynamics in supercritical CO2-ethanol mixtures and the effect of hydrogen bonding on single reorientational and translational dynamics: A molecular dynamics simulation study
Authors: Skarmoutsos Ioannis , Guardia Elvira , Samios Jannis
Published: July 2010

The hydrogen bonding and dynamics in a supercritical mixture of carbon dioxide with ethanol as a cosolvent (Xethanol∼0.1) were investigated using molecular dynamics simulation techniques. The results obtained reveal that the hydrogen bonds formed between ethanol molecules are significantly more in comparison with those between ethanol-CO2 molecules and also exhibit much larger lifetimes. Furthermore, the residence dynamics in the solvation shells of ethanol and CO2 have been calculated, revealing much larger residence times for ethanol molecules in the ethanol solvation shell. These results support strongly the ethanol aggregation effects and the slow local environment reorganization inside the ethanol solvation shell, reported in a previous publication of the authors [Skarmoutsos et al., J. Chem. Phys. 126, 224503 (2007)]. The formation of electron donor-acceptor dimers between the ethanol and CO2 molecules has been also investigated and the calculated lifetimes of these complexes have been found to be similar to those corresponding to ethanol-CO2 hydrogen bonds, exhibiting a slightly higher intermittent lifetime. However, the average number of these dimers is larger than the number of ethanol-CO2 hydrogen bonds in the system. Finally, the effect of the hydrogen bonds formed between the individual ethanol molecules on their reorientational and translational dynamics has been carefully explored showing that the characteristic hydrogen bonding microstructure obtained exhibits sufficiently strong influence upon the behavior of them.
Interaction between physical aging, deformation, and segmental mobility in poly(methyl methacrylate) glasses
Authors: Lee Hau-Nan , Ediger M. D.
Published: July 2010

Optical photobleaching experiments were used to investigate the interaction between physical aging, segmental mobility, and mechanical properties in polymer glasses. Mechanical creep experiments were performed on lightly cross-linked poly(methyl methacrylate) glasses with systematically varying aging histories. By directly measuring the molecular mobility of polymer glasses under deformation, we observe that stresses in the preflow regime and flow regime have qualitatively different influences on the aging process. In the preflow regime, the effects of aging and stress on mobility act as two independent processes; stress causes an increase in segmental mobility but does not erase the influence of previous aging. In contrast, as a sample enters the flow regime, plastic deformation takes the glass into a high mobility state that is independent of any predeformation aging history.
Finite element simulation for ultraviolet excimer laser processing of patterned Si/SiGe/Si(100) heterostructures
Authors: Conde J. C. , Martín E. , Chiussi S. , Gontad F. , Serra C. , González P.
Published: July 2010

Ultraviolet (UV) Excimer laser assisted processing is an alternative strategy for producing patterned silicon germanium heterostructures. We numerically analyzed the effects caused by pulsed 193 Excimer laser radiation impinging on patterned amorphous hydrogenated silicon (a-Si:H) and germanium (a-Ge:H) bilayers deposited on a crystalline silicon substrate [Si(100)]. The proposed two dimensional axisymmetric numerical model allowed us to estimate the temperature and concentration gradients caused by the laser induced rapid melting and solidification processes. Energy density dependence of maximum melting depth and melting time evolution as well as three dimensional temperature and element distribution have been simulated and compared with experimentally obtained results.
Synthesis and thermoelectric properties of RuO2 nanorods
Authors: Music Denis , Basse Felix H.-U. , Haßdorf Ralf , Schneider Jochen M.
Published: July 2010

We have explored the effect of the O/Ru ratio on the morphology and the Seebeck coefficient of RuO2 nanorods (space group P42/mnm) synthesized by reactive sputtering. At an O/Ru ratio of 1.69, a faceted surface is observed, while nanorod formation occurs at O/Ru ratios of 2.03 and 2.24. Using classical molecular dynamics with the potential parameters derived in this work, we show that volatile species enable nanorod formation. Based on ab initio calculations, two effects of the nanorod formation on the Seebeck coefficient are observed: (i) increase due to additional states in the vicinity of the Fermi level and (ii) decrease due to oxygen point defects (volatile species). These two competing effects give rise to a moderate increase in the Seebeck coefficient upon nanorod formation.
Nanopore fabrication in amorphous Si: Viscous flow model and comparison to experiment
Authors: George H. Bola , Tang Yuye , Chen Xi , Li Jiali , Hutchinson John W. , Golovchenko Jene A. , Aziz Michael J.
Published: July 2010

Nanopores fabricated in free-standing amorphous silicon thin films were observed to close under 3 keV argon ion irradiation. The closing rate, measured in situ, exhibited a memory effect: at the same instantaneous radius, pores that started larger close more slowly. An ion-stimulated viscous flow model is developed and solved in both a simple analytical approximation for the small-deformation limit and in a finite element solution for large deformations. The finite-element solution exhibits surprising changes in cross-section morphology, which may be extremely valuable for single biomolecule detection, and are untested experimentally. The finite-element solution reproduces the shape of the measured nanopore radius versus fluence behavior and the sign and magnitude of the measured memory effect. We discuss aspects of the experimental data not reproduced by the model, and successes and failures of the competing adatom diffusion model.
Communications: Direct dynamics study of the O(P3)+C2H2 reaction: Contribution from spin nonconserving route
Authors: Rajak Karunamoy , Maiti Biswajit
Published: July 2010

The importance of intersystem crossing dynamics for the O(P3)+C2H2 reaction is demonstrated in this work. A direct dynamics trajectory surface hopping method has been employed to study the intersystem crossing effects. Our study reveals that there is a significant contribution from the spin nonconserving route to the chemical dynamics of the O(P3)+C2H2 reaction, despite small spin-orbit coupling constant values (<70 cm−1).
Monte Carlo simulations of the solid-liquid transition in hard spheres and colloid-polymer mixtures
Authors: Zykova-Timan T. , Horbach J. , Binder K.
Published: July 2010

Monte Carlo simulations at constant pressure are performed to study coexistence and interfacial properties of the liquid-solid transition in hard spheres and in colloid-polymer mixtures. The latter system is described as a one-component Asakura–Oosawa (AO) model where the polymer’s degrees of freedom are incorporated via an attractive part in the effective potential for the colloid-colloid interactions. For the considered AO model, the polymer reservoir packing fraction is ηpr=0.1 and the colloid-polymer size ratio is q≡σp/σ=0.15 (with σp and σ as the diameter of polymers and colloids, respectively). Inhomogeneous solid-liquid systems are prepared by placing the solid fcc phase in the middle of a rectangular simulation box, creating two interfaces with the adjoined bulk liquid. By analyzing the growth of the crystalline region at various pressures and for different system sizes, the coexistence pressure pco is obtained, yielding pco=11.576 kBT/σ3 for the hard-sphere system and pco=8.00 kBT/σ3 for the AO model (with kB as the Boltzmann constant and T as the temperature). Several order parameters are introduced to distinguish between solid and liquid phases and to describe the interfacial properties. From the capillary-wave broadening of the solid-liquid interface, the interfacial stiffness is obtained for the (100) crystalline plane, giving the values γ̃≈0.49 kBT/σ2 for the hard-sphere system and γ̃≈0.95 kBT/σ2 for the AO model.
Relation between the barrier interface and the built-in potential in pentacene/C60 solar cell
Authors: Nolasco J. C. , Sánchez-Díaz Antonio , Cabré R. , Ferré-Borrull J. , Marsal L. F. , Palomares E. , Pallarès J.
Published: July 2010

The mechanisms limiting the dark current in pentacene (Pc)/C60 solar cell were determined using the temperature dependence of the current-density-voltage characteristics. Our analysis allowed us to calculate the effective barrier height for electrons and holes at the interface. We then determined the built-in potential of the heterojunction and the effective doping concentration of the active layers, using capacitance-voltage characteristics. These physical parameters were used to simulate a band-energy diagram for a Pc/C60 solar cell in equilibrium. Finally, we determined a relation between the effective barrier height and the built-in potential.
Linear scaling coupled cluster method with correlation energy based error control
Authors: Ziółkowski Marcin , Jansík Branislav , Kjærgaard Thomas , Jørgensen Poul
Published: July 2010

Coupled cluster calculations can be carried out for large molecular systems via a set of calculations that use small orbital fragments of the full molecular orbital space. The error in the correlation energy of the full molecular system is controlled by the precision in the small fragment calculations. The determination of the orbital spaces for the small orbital fragments is black box in the sense that it does not depend on any user—provided molecular fragmentation, rather orbital spaces are carefully selected and extended during the calculation to give fragment energies of a specified precision. The computational method scales linearly with the size of the molecular system and is massively parallel.
End-of-range defects in germanium and their role in boron deactivation
Authors: Panciera F. , Fazzini P. F. , Collet M. , Boucher J. , Bedel E. , Cristiano F.
Published: July 2010

We investigated the thermal evolution of end-of-range (EOR) defects in germanium and their impact on junction thermal stability. After solid-phase epitaxial regrowth of a preamorphized germanium layer, EOR defects exhibiting dislocation loop-like contrast behavior are present. These defects disappear during thermal annealing at 400 °C, while boron electrical deactivation occurs. After the whole defect population vanishes, boron reactivation is observed. These results indicate that germanium self-interstitials, released by EOR defects, are the cause of B deactivation. Unlike in Si, the whole deactivation/reactivation cycle in Ge is found to take place while the maximum active B concentration exceeds its solubility limit.
Fluctuation power spectra reveal dynamical heterogeneity of peptides
Authors: Khatri Bhavin , Yew Zu Thur , Krivov Sergei , McLeish Tom , Paci Emanuele
Published: July 2010

Characterizing the conformational properties and dynamics of biopolymers and their relation to biological activity and function is an ongoing challenge. Single molecule techniques have provided a rich experimental window on these properties, yet they have often relied on simple one-dimensional projections of a multidimensional free energy landscape for a practical interpretation of the results. Here, we study three short peptides with different structural propensity (α helical, β hairpin, and random coil) in the presence (or absence) of a force applied to their ends using Langevin dynamics simulation and an all-atom model with implicit solvation. Each peptide produces fluctuation power spectra with a characteristic dynamic fingerprint consistent with persistent structural motifs of helices, hairpins, and random coils. The spectra for helix formation shows two well-defined relaxation modes, corresponding to local relaxation and cooperative coil to uncoil interconversion. In contrast, both the hairpin and random coil are polymerlike, showing a broad and continuous range of relaxation modes giving characteristic power laws of ω−5/4 and ω−3/2, respectively; the −5/4 power law for hairpins is robust and has not been previously observed. Langevin dynamics simulations of diffusers on a potential of mean force derived from the atomistic simulations fail to reproduce the fingerprints of each peptide motif in the power spectral density, demonstrating explicitly that such information is lacking in such one-dimensional projections. Our results demonstrate the yet unexploited potential of single molecule fluctuation spectroscopy to probe more fine scaled properties of proteins and biological macromolecules and how low dimensional projections may cause the loss of relevant information.
Electronic effects of single H atoms on Ge(001) revisited
Authors: Shah G. A. , Radny M. W. , Smith P. V. , Schofield S. R. , Curson N. J.
Published: July 2010

The adsorption of isolated H atoms on the Ge(001) surface is studied using density functional theory (DFT) and scanning tunneling microscopy (STM). Two stable adsorption positions that are found in DFT correspond to H atom attachment to an up-or down-buckled Ge dimer atom, respectively. Surprisingly, in the case where H bonds to the down-buckled Ge atom, we find that there is a redistribution of a unit of charge which leaves the net charge of the doubly occupied dangling bond of the unreacted Ge atom intact. This configuration is found to be the more stable of the two structures. Comparison to filled- and empty-state STM images confirms that this lowest energy structure is observed at room temperature. These results represent a fundamentally different picture of the physics and chemistry of H adsorption to Ge(001) compared with previous work.
Photodissociation dynamics of acetylene via the C̃ Π1u electronic state
Authors: Zhang Yongwei , Yuan Kaijun , Yu Shengrui , Parker David H. , Yang Xueming
Published: July 2010

Photodissociation of acetylene has been studied using the H-atom Rydberg tagging time-of-flight technique at two excitation wavelengths (148.35 and 151.82 nm) in the vacuum ultraviolet region. Product translational energy distributions have been obtained from the H-atom time-of-flight spectra. Experimental results indicate that the C2H product is mainly populated in the Ã state. Clear trans-bend ν2 and C–C stretch ν3 vibrational progressions of the C2H(Ã) product in the product internal energy distribution were observed. The anisotropy parameter obtained from experiment is clearly translational energy dependent for both photolysis wavelengths. The anisotropy parameters at the two photolysis wavelengths were also found to be significantly different from each other, suggesting different dissociation dynamics for the two photolysis wavelengths.
Optically induced fast wavelength modulation in a quantum cascade laser
Authors: Chen Gang , Martini Rainer , Park Seong-wook , Bethea Clyde G. , Chen I.-Chun A. , Grant P. D. , Dudek R. , Liu H. C.
Published: July 2010

An optically induced fast wavelength shift is demonstrated in a standard middle infrared (MIR) quantum cascade laser (QCL) by illuminating the front facet with a femtosecond (fs) near infrared (NIR) laser, allowing fast optical frequency modulation (FM) for free space optical communication (FSOC) and FM spectroscopy. Using an etalon as a narrow band-pass wavelength filter, the wavelength modulation (WM) was clearly observed at frequencies up to 1.67 GHz. This approach can also be used for wavelength conversion and might be extended to QCLs operating in different wavelength regions.
The dissociation of NO–Ar(Ã) from around threshold to 200 cm−1 above threshold
Authors: Holmes-Ross Heather L. , Lawrance Warren D.
Published: July 2010

We report an investigation of the dissociation of Ã state NO–Ar at energies from 23 cm−1 below the dissociation energy to 200 cm−1 above. The NO product rotational distributions show population in states that are not accessible with the energy available for excitation from the NO ground state. This effect is observed at photon energies from below the dissociation energy up to approximately 100 cm−1 above it. Translational energy distributions, extracted from velocity map images of individual rotational levels of the NO product, reveal contributions from excitation of high energy NO–Ar X̃ states at all the excess energies probed, although this diminishes with increasing photon energy and is quite small at 200 cm−1, the highest energy studied. These translational energy distributions show that there are contributions arising from population in vibrational levels up to the X̃ state dissociation energy. We propose that the reason such sparsely populated levels contribute to the observed dissociation is a considerable increase in the transition moment, via the Franck–Condon factor associated with these highly excited states, which arises because of the quite different geometries in the NO–Ar X̃ and Ã states. This effect is likely to arise in other systems with similarly large geometry changes.
Driving method of microtool by horizontally arranged permanent magnets for single cell manipulation
Authors: Hagiwara Masaya , Kawahara Tomohiro , Yamanishi Yoko , Arai Fumihito
Published: July 2010

This paper presents an innovative driving method for a magnetically driven microtool to achieve precise positioning control while maintaining a high power output derived from commercialized permanent magnets. An effective driving methodology using permanent magnets, whose axes are parallel to driving direction, is applied to reduce friction force on the microtool. The positioning accuracy improves by five times and the response speed becomes ten times faster against the driving stage than in the conventional method. Furthermore, this method has been extended to two-degree-of-freedom movements, and the performance of the magnetically driven microtools is experimentally validated by oocyte manipulation.
Electron transport properties of InAs ultrathin films obtained by epitaxial lift-off and van der Waals bonding on flexible substrates
Authors: Takita Hayato , Hashimoto Norihiko , Nguyen Cong Thanh , Kudo Masahiro , Akabori Masashi , Suzuki Toshi-kazu
Published: July 2010

We investigated InAs ultrathin films on flexible substrates. InAs layers grown on GaAs(001) are separated by epitaxial lift-off (ELO), followed by van der Waals bonding (VWB) on flexible substrates. We employed “normal” and “inverted” VWB; in the former, top and bottom sides are maintained during ELO and VWB, while inverted in the latter. From the InAs on flexible substrates, we fabricated Hall-bar devices with recess etch-thinning, using which electron transport properties depending on InAs layer thickness were characterized. For the inverted VWB, we observe very high electron mobilities of InAs ultrathin films, such as ∼10 000 cm2/V s for ∼100 nm thickness and ∼7000 cm2/V s for ∼20 nm. These carrier mobilities are highest not only for thin films on flexible substrates but also for InAs thin films; higher than those of InAs films grown on GaAs(111)A and membranes fabricated from them.