bluuebunny/crossref_metadata_2025 huggingface dataset:
Cross-leg lithotomy: is it a better position for digital rectal examination of the prostate?
Authors: Nagathan Deepak Sharanappa , Dalela Divakar , Sankhwar Satyanarayan , Goel Apul , Dwivedi Amod Kumar , Yadav Rahul , Dalela Deepansh , Gupta Dheeraj Kumar , Mandal Swarnendu
Published: July 2012

Objectives

To evaluate whether “cross-leg lithotomy” (CL) is better position for digital rectal examination (DRE) than left lateral (LL) position from urologist and patient's perspective.

Materials and methods

Two urologists performed DRE in 120 patients in LL and CL positions. Each patient was randomised, sequentially examined in both positions and responses were objectively assessed using a questionnaire and statistically analysed.

Results

Men found DRE uncomfortable [LL (81.7%), CL (85.0%)] and embarrassing [LL: (81.7%), CL (78.3%)] in both the positions. DRE was painful [LL (11.7%), CL (8.3%)] with a mean pain score of 1.92 and 1.85 respectively. Patient apprehension regarding pain was significantly higher [LL (62.5%) vs. CL (21.7%), p < 0.001] in LL position. Overall, men preferred CL to LL position [CL (78.3%), LL (21.75%), p < 0.001] for DRE. From urologist perspective, the extent of prostate felt in CL position was significantly higher (CL: 11.15 ± 1.96/12 vs. LL: 9.25 ± 2.50/12, p < 0.001). Withdrawal response was significantly higher in LL and urologist had to sit down to perform DRE in LL position.

Conclusions

Men preferred CL to LL position for DRE and CL allowed more complete examination of the prostate from urologist perspective. CL position is a better alternative for performing DRE of the prostate.
Yeast as a model system for studying lipid homeostasis and function
Authors: Santos Aline X.S. , Riezman Howard
Published: July 2012

Lipids are essential eukaryotic cellular constituents. Lipid metabolism has a strong impact on cell physiology, and despite good progress in this area, many important basic questions remain unanswered concerning the functional diversity of lipid species and on the mechanisms that cells employ to sense and adjust their lipid composition. Combining convenient experimental tractability, a large degree of conservation of metabolic pathways with other eukaryotes and the relative simplicity of its genome, proteome and lipidome, yeast represents the most advantageous model organism for studying lipid homeostasis and function. In this review we will focus on the importance of yeast as a model organism and some of the innovative advantages for the lipid research field.
Magnetic resonance imaging in a patient with an implantable cardiac defibrillator
Authors: Furusho MD Hiroshi , Kusayama MD Takashi , Chikata MD Akio , Kobayashi MD Daisuke , Murai MD Hisayoshi , Usui MD Soichiro , Okajima MD Masaki , Kaneko MD Shuichi , Yamagishi MD Masakazu , Takamura MD Masayuki
Published: July 2012

A 58‐year‐old man, in whom an implantable cardiac defibrillator (ICD) had been implanted for Brugada syndrome, suffered rapidly progressive general paralysis. Various diagnostic imaging techniques were performed, but the cause could not be determined. Magnetic resonance imaging (MRI) scanning was performed. A 1.5‐Tesla MRI system was used, and the ICD was programmed to ODO mode and all tachycardia detection was turned off. MRI was performed safely under electrocardiogram and pulse oximeter monitoring, and appropriate precautions were taken in preparation for an emergency. ICD parameters did not change in post‐imaging investigations. MRI revealed an apparent tumor in the patient's medulla and upper cervical spinal cord, which was diagnosed as high‐grade astrocytoma. When performing MRI procedures in patients with an ICD under urgent conditions, it is necessary to have complete knowledge of the procedure and to make careful preparations.
Symptomatological and cognitive correlates of vascular comorbidity in older‐elderly (at least 75 years old) men with major depressive disorder
Authors: Wang Yu‐Yuan , Chang Yun‐Hsuan , Lee Sheng‐Yu , Huang Chih‐Chun , Lee I‐Hui , Yeh Tzung‐Lieh , Yang Yen‐Kuang , Ku Yan‐Chiou , Lu Ru‐Band
Published: July 2012

Depression is a common geriatric psychiatric disorder increasing with age among elderly people (≥ 75 years old), especially those with medical comorbidities. They have higher suicide rates than younger men, but these are paid less attention. Elderly men (n = 141) who were newly admitted residents of the Veterans' Home in Tainan, Taiwan from 2004 to 2006 were recruited and screened for major depression. Specialist physicians obtained past histories of medical illnesses through chart reviews, interview, and health examinations. Fifty‐nine of the 141 elderly people had major depression and participated in this study. Thirty‐nine men in the group with vascular comorbidities (VC), and 20 in the group without (NVC) vascular comorbidities were compared. The VC group had more time‐orientation impairment, greater psychomotor retardation, and diminished concentration/decision‐making than did the NVC group. Psychomotor retardation and other cognitive function impairments (e.g., concentration and decision‐making) are characteristic manifestations among patients with major depression and vascular comorbidity compared with those without vascular comorbidity.
Yusho: 43 years later
Authors: Yoshimura Takesumi
Published: July 2012

The aim of the present study is to describe recent issues with Yusho disease in Japan, describe the state of dioxin accumulation and the intake of dioxin via food in Japan, and introduce the Japan Environment and Children's Study. Yusho disease manifested in western Japan in 1968. The causes of Yusho are believed to be dioxin‐related compounds, mainly polychlorinated biphenyls (PCBs) and polychlorinated dibenzofurans (PCDFs), via the ingestion of rice oil produced in February 1968. As of March 31, 2011, there were 1961 registered Yusho cases, but of these 539 are deceased. A retrospective cohort study on registered Yusho cases reported that the standardized mortality ratios (SMRs) for the major causes of death were not significantly elevated, with the exception of all‐cancer (SMR = 1.26; 95% confidence interval [CI]: 1.03–1.53) and lung cancer mortality (SMR = 1.56; 95% CI: 1.03–2.27) in males. The results of the Yusho mortality study show that the SMR for liver cancer in males tends to decrease over time. In 2011, the Ministry of the Environment of Japan reported that the average concentration of dioxins in the blood (2002–2010) of the Japanese people was 19 pg‐TEQ/g‐fat, demonstrating a range of 0.10–130 pg‐TEQ/g‐fat, and that the average dioxin intake from food (2002–2010) was 0.82 pg‐TEQ/kg‐body weight/day, demonstrating a range of 0.031–6.2 pg‐TEQ/kg‐body weight/day according to 2006 WHO TEFs. The Japan Environment and Children's Study Project was launched in 2011 and is supported by the Ministry of the Environment of Japan. In this project, 100,000 mother and child pairs will be recruited over 3 years from designated study areas. Follow‐up examinations will be carried out from pregnancy until the children are 13 years of age (a so‐called birth‐cohort study). This project will be implemented by the National Center at the National Institute for Environmental Studies and is supported by the Medical Support Center at the National Center for Child Health and Development. Field operations will be performed at 15 designated regional centers nationwide.
A 10‐Year Incidence of Acute Whiplash Injuries After Road Traffic Crashes in a Defined Population in Northern Sweden
Authors: Styrke Johan , Stålnacke Britt‐Marie , Bylund Per‐Olof , Sojka Peter , Björnstig Ulf
Published: July 2012

Objective

To examine the annual incidence of acute whiplash injuries after road traffic crashes in a geographic catchment area in Northern Sweden during the period 2000‐2009.

Design

Descriptive epidemiology determined by prospectively collected data from a defined population.

Setting

The study was conducted at a public hospital in Sweden.

Participants

The population of the hospital's catchment area (136,600 inhabitants in 1999 and 144,500 in 2009).

Methods

At the emergency department, all injured persons (approximately 11,000 per year) were asked to answer a questionnaire about the injury incident. Data from the medical records also were analyzed. From 2000‐2009, 15,506 persons were injured in vehicle crashes. Persons who were subject to an acute neck injury within whiplash‐associated disorder grades 1‐3 were included. The overall and annual incidences were calculated as incidence. Age, gender, type of injury event, and direction of impact were described. The incidences were compared with national statistics on insurance claims from 2003, 2007, and 2008 to detect changes in the proportions of claims.

Main Outcome Measures

The annual incidence of acute whiplash injuries. Secondary outcome measures were types of injury events, age and gender distribution, changes in the proportion of rear‐end crashes during 2000‐2009, and changes in the proportion of insurance claims during 2003‐2008.

Results

During 2000‐2009, 3297 cases of acute whiplash injury were encountered. The overall incidence was 235/100,000/year. The average yearly increase in incidence was 1.0%. Women comprised 51.9% and men 48.1% of the injured. Car occupants (86.4%) and bicycle riders (6.1%) were most frequently injured. The proportion of rear‐end crashes decreased from 55% to 45% from 2000‐2009. The proportion of insurance claims significantly decreased between 2003 and 2008 (P < .0001, χ2 test).

Conclusion

The incidence of emergency department visits attributable to acute whiplash injuries after road traffic crashes have been relatively stable during the past decade in our area, except in 2007 and 2008, when a peak occurred.
Nicht-lineare Zusammenhänge zwischen Intention und Verhalten
Authors: Lippke Sonia , Ernsting Anna , Richert Jana , Parschau Linda , Koring Milena , Schwarzer Ralf
Published: July 2012

Zusammenfassung. Bekanntlich sind viele Menschen weniger körperlich aktiv als empfohlen oder als sie es selbst beabsichtigen. Ziel dieser Studie ist es, die Prävalenzen von körperlicher Aktivität einerseits mit den offiziellen Empfehlungen und andererseits mit den Intentionen von Personen zu vergleichen sowie Verhalten längsschnittlich vorherzusagen. Dafür wurden Befragungsdaten von 492 Frauen und Männern zu drei Messzeitpunkten im Abstand von ca. 3 Wochen und 6,5 Wochen untersucht. Wie erwartet lagen die Prävalenzen sowohl unterhalb der Empfehlungen als auch unterhalb der eigenen Intentionen. Früheres Verhalten, Intention und Selbstwirksamkeitserwartung konnten gemeinsam spätere körperliche Aktivität vorhersagen. Bei der Analyse nicht-linearer Zusammenhänge von Intention und berichtetem Verhalten zeigte sich darüber hinaus, dass vor allem ein Mittelmaß an Intention funktional für tatsächliche Verhaltensausübung ist: gute Absichten müssen realistisch sein, um in die Tat umgesetzt werden zu können. Dies gilt insbesondere für Menschen mit Übergewicht, für die spezielle Empfehlungen für die Ausübung von körperlicher Aktivität vorliegen.
Evaluation des Gesundheitsförderungsprogramms „Aktive Bewältigung von Arbeitslosigkeit (AktivA)”
Authors: Rothländer Katrin , Mühlpfordt Susann , Richter Peter
Published: July 2012

Zusammenfassung. Die vorliegende Evaluationsstudie untersucht die Wirksamkeit des Gesundheitsförderungsprogramms „Aktive Bewältigung von Arbeitslosigkeit” (AktivA), das bewährte kognitiv-behaviorale Techniken an Erwerbslose vermittelt. Anhand eines Prä-Post-Kontrollgruppenplans werden Effekte auf psychische, körperliche und sozial-kommunikative Gesundheit sowie auf Selbstwirksamkeitserwartung und wahrgenommene soziale Unterstützung geprüft. Es werden zwei unterschiedliche Zugänge betrachtet: 1. Integration des AktivA-Trainings in arbeitsmarktpolitische Maßnahmen (Interventionsgruppe (IG) n = 258/Kontrollgruppe (KG) n = 211), 2. frei zugängliches Trainingsangebot, das bei Erwerbslosen beworben wird (IG n = 184/KG n = 111). Unmittelbar nach dem Training zeigen sich in beiden Interventionsgruppen im Vergleich zu den Kontrollgruppen statistisch bedeutsame Verringerungen der gesundheitlichen Beschwerden. Bei den Teilnehmern des freien Trainingsangebotes wird zudem die wahrgenommene soziale Unterstützung gesteigert. Während die Effekte drei Monate nach dem Training im freien Zugang weiterhin bestehen, können sie im Setting Beschäftigungsträger nicht aufrechterhalten werden. Mögliche Einflussgrößen wie unterschiedliche gesundheitliche Ausgangswerte der Interventionsgruppen, motivationale Unterschiede sowie eine eventuelle Konfundierung mit dem Ende der Beschäftigungsmaßnahme werden diskutiert.
Detachment From Work in Airport Hotels
Authors: Searle Ben J.
Published: July 2012

The work of airline pilots is demanding and must be followed by rest periods (slips) so that pilots recover sufficiently well to keep flying safely. When slips occur away from home base, pilots are usually accommodated in a hotel. This paper reviews the phenomenon of psychological detachment from work (i.e., not thinking about work) and its implications for pilot accommodation and recovery. The review suggests that pilots accommodated in hotels located in or close to airports may be less able to psychologically detach from work during slips, with implications for recovery, fatigue, and ultimately safety. The paper presents a rationale for considering psychological detachment from work when evaluating the quality of hotels chosen for pilots.
Silence That May Kill
Authors: Bienefeld Nadine , Grote Gudela
Published: July 2012

Several accidents have shown that crew members’ failure to speak up can have devastating consequences. Despite decades of crew resource management (CRM) training, this problem persists and still poses a risk to flight safety. To resolve this issue, we need to better understand why crew members choose silence over speaking up. We explored past speaking up behavior and the reasons for silence in 1,751 crew members, who reported to have remained silent in half of all speaking up episodes they had experienced. Silence was highest for first officers and pursers, followed by flight attendants, and lowest for captains. Reasons for silence mainly concerned fears of damaging relationships, of punishment, or operational pressures. We discuss significant group differences in the frequencies and reasons for silence and suggest customized interventions to specifically and effectively foster speaking up.
Simulator Sickness in Flight Simulators of the German Armed Forces
Authors: Stein Michael , Robinski Maxi
Published: July 2012

We investigated simulator sickness in jet simulators without motion platforms (Eurofighter), and in a helicopter simulator (EC 135) as well as in a reconnaissance aircraft simulator (P-3C-Orion) with motion simulation. In addition, workload, visual fatigue, and vitality of pilots were measured. In contrast to jet simulators, where no flashbacks were reported, the EC 135 and the P-3C-Orion simulators proved to be problematic, causing severe simulator sickness symptoms or flashbacks. In all three studies, simulator sickness correlated positively with workload and visual fatigue, while correlating negatively with vitality. In line with previous findings, compared with no-motion simulators, motion-based simulators evoke simulator sickness more easily. Back assumptions that higher workload can reduce simulator sickness could not be proved, since positive correlations were found.
Variation and Aviation: Language and Statistical Power
Authors: de Voogt Alex
Published: July 2012

Large datasets from aviation accident databases allow for advanced statistical analyses. The results from one such analysis of helicopter night-time accidents show that this type of study is likely to separate the researcher from what can be understood in an aviation context.
Generation of a quasi-monoergetic proton beam from laser-irradiated sub-micron droplets
Authors: Ter-Avetisyan S. , Ramakrishna B. , Prasad R. , Borghesi M. , Nickles P. V. , Steinke S. , Schnürer M. , Popov K. I. , Ramunno L. , Zmitrenko N. V. , Yu. Bychenkov V.
Published: July 2012

Proton bursts with a narrow spectrum at an energy of (2.8 ± 0.3 MeV) are accelerated from sub-micron water spray droplets irradiated by high-intensity (∼5 × 1019 W/cm2), high-contrast (∼1010), ultra-short (40 fs) laser pulses. The acceleration is preferentially in the laser propagation direction. The explosion dynamics is governed by a residual ps-scale laser pulse pedestal which “mildly” preheats the droplet and changes its density profile before the arrival of the high intensity laser pulse peak. As a result, the energetic electrons extracted from the modified target by the high-intensity part of the laser pulse establish an anisotropic electrostatic field which results in anisotropic Coulomb explosion and proton acceleration predominantly in the forward direction. Hydrodynamic simulations of the target pre-expansion and 3D particle-in-cell simulations of the measured energy and anisotropy of the proton emission have confirmed the proposed acceleration scenario.
A Reynolds-averaged turbulence modeling approach using three transport equations for the turbulent viscosity, kinetic energy, and dissipation rate
Authors: Yoshizawa Akira , Abe Hiroyuki , Matsuo Yuichi , Fujiwara Hitoshi , Mizobuchi Yasuhiro
Published: July 2012

A Reynolds-averaged approach to turbulent shear flows is sought with resort to a three-equation method. Its novelty is the introduction of a turbulent-viscosity transport equation through the transport equation for the Reynolds stress in addition to those for the turbulent kinetic energy and the dissipation rate. The latter two equations are used for evaluating the dimensional coefficients in the former. The aim of this model is to enhance the capability to cope with nonstationary and advection effects in various turbulent flows. The adaptability to them is confirmed through the application to homogeneous-shear and supersonic free-shear flows. In particular, the reasonable prediction is obtained in the latter where the growth rate of the shear layer is suppressed with the increase in the convective Mach number. The present model is also applied to a three-dimensional flow past a wing tip as an instance of complex aeronautical flows, and the excessive diffusion of the trailing vortices is shown to be suppressed. The turbulent-viscosity representation for the Reynolds stress is systematically supplemented with nonlinear effects of mean-velocity gradient tensors, and its adequacy is verified in a channel flow.
Breakup and vaporization of droplets under locally supersonic conditions
Authors: Kim YoungJun , Hermanson James C.
Published: July 2012

The disruption and vaporization of simulated fuel droplets in an accelerating supersonic flow was examined experimentally in a draw-down supersonic wind tunnel. The droplets achieved supersonic velocities relative to the surrounding air to give relative Mach numbers of up to 1.8 and Weber numbers of up to 300. Mono-disperse, 100 μm-diameter fluid droplets were generated using a droplet-on-demand generator upstream of the tunnel entrance. Direct close-up single- and multiple-exposure imaging was used to examine the features of droplet breakup and to determine the droplet velocities. Laser-induced fluorescence (LIF) imaging of the disrupting droplets was performed using acetone fluorescence to determine the dispersion of the expelled vapor. Three test liquids were employed: 2-propanol and tetraethylene glycol dimethyl ether as non-volatile fluids and a 50/50 hexanol-pentane mixture (Hex-Pen 50/50). The vapor pressure of the Hex-Pen 50/50 was sufficiently high to cause the droplet fluid to potentially become superheated in the decreased static pressure of the supersonic stream. The dynamics for 2-propanol and Hex-Pen 50/50 droplets were similar up to the point of disruption, which occurred more rapidly for the more volatile Hex-Pen 50/50. A 1D dynamic droplet model was developed to provide a first estimate of the expected droplet acceleration and velocity. The actual droplet velocities were in reasonable agreement with the model up to the point at which significant droplet disruption and mass loss commenced. The droplet deformation and breakup patterns for these supersonic flow conditions can be classified into four different flow regions characterized by changes in the Weber number with downstream distance as the droplets accelerate, however, those flow regimes and Weber number ranges were different than those seen for droplets disrupting in shock tubes. The disruption patterns were seen to be generally similar for the different fluids, though droplet disruption occurred more rapidly for the more volatile fluid. LIF imaging established the extent of the dispersion of the expelled vapor. Examination of the vapor clouds surrounding the droplets suggests that Hex-Pen 50/50 droplets had a greater rate of vaporization than 2-propanol droplets starting at approximately 2 mm downstream of the nozzle throat, where the air static pressure became lower than the liquid vapor pressure. This suggests that droplet superheating can have an effect on the extent and rate of droplet vaporization under locally supersonic conditions. The degree of vaporization for Hex-Pen 50/50 was approximately 1.3 times greater than that of the non-volatile fluids over all downstream distances in the supersonic flow.
Transition-density-fragment interaction combined with transfer integral approach for excitation-energy transfer via charge-transfer states
Authors: Fujimoto Kazuhiro J.
Published: July 2012

A transition-density-fragment interaction (TDFI) combined with a transfer integral (TI) method is proposed. The TDFI method was previously developed for describing electronic Coulomb interaction, which was applied to excitation-energy transfer (EET) [K. J. Fujimoto and S. Hayashi, J. Am. Chem. Soc. 131, 14152 (2009)] and exciton-coupled circular dichroism spectra [K. J. Fujimoto, J. Chem. Phys. 133, 124101 (2010)]. In the present study, the TDFI method is extended to the exchange interaction, and hence it is combined with the TI method for applying to the EET via charge-transfer (CT) states. In this scheme, the overlap correction is also taken into account. To check the TDFI-TI accuracy, several test calculations are performed to an ethylene dimer. As a result, the TDFI-TI method gives a much improved description of the electronic coupling, compared with the previous TDFI method. Based on the successful description of the electronic coupling, the decomposition analysis is also performed with the TDFI-TI method. The present analysis clearly shows a large contribution from the Coulomb interaction in most of the cases, and a significant influence of the CT states at the small separation. In addition, the exchange interaction is found to be small in this system. The present approach is useful for analyzing and understanding the mechanism of EET.
Scalable properties of metal clusters: A comparative study of modern exchange-correlation functionals
Authors: Koitz Ralph , Soini Thomas M. , Genest Alexander , Trickey S. B. , Rösch Notker
Published: July 2012

The performance of eight generalized gradient approximation exchange-correlation (xc) functionals is assessed by a series of scalar relativistic all-electron calculations on octahedral palladium model clusters Pdn with n = 13, 19, 38, 55, 79, 147 and the analogous clusters Aun (for n up through 79). For these model systems, we determined the cohesive energies and average bond lengths of the optimized octahedral structures. We extrapolate these values to the bulk limits and compare with the corresponding experimental values. While the well-established functionals BP, PBE, and PW91 are the most accurate at predicting energies, the more recent forms PBEsol, VMTsol, and VT{84}sol significantly improve the accuracy of geometries. The observed trends are largely similar for both Pd and Au. In the same spirit, we also studied the scalability of the ionization potentials and electron affinities of the Pd clusters, and extrapolated those quantities to estimates of the work function. Overall, the xc functionals can be classified into four distinct groups according to the accuracy of the computed parameters. These results allow a judicious selection of xc approximations for treating transition metal clusters.
Spin-lattice relaxation of the methyl group protons in solids revisited: Damped quantum rotation approach
Authors: Szymański S.
Published: July 2012

Proton spin-lattice relaxation of the methyl group in solids had been one of the most thoroughly addressed theoretical problems in nuclear magnetic resonance (NMR) spectroscopy, considered at different levels of sophistication. For systems with substantial quantum tunneling effects, several quantum mechanical treatments were reported, although in practical applications the quantum models were always augmented with or replaced by the classical jump model. However, the latter has recently proved invalid in the description of NMR line shape effects in variable-temperature spectra of hindered methyl groups, while the competing theory of damped quantum rotation (DQR) was shown to be adequate. In this work, the spin-lattice relaxation issue for the methyl protons is readdressed using the latter theory. The main outcome is that, while the existing formulas for the relaxation rates remain unchanged, the crucial parameter entering them, the correlation time of the relevant random process, need to be reinterpreted. It proves to be the inverse of one of the two quantum-rate constants entering the DQR model, neither of which, when taken separately, can be related to the jump process. It can be identified with one describing the life-time broadening of the tunnel peaks in inelastic neutron scattering (INS) spectra of the methyl groups. Such a relationship between the relaxation and INS effects was reported from another laboratory long ago, but only for the low-temperature limit where thermal population of the excited torsional levels of the methyl group can be neglected. The whole spectrum of cases encountered in practical relaxation studies on protonated methyl groups is addressed for the first time. Preliminary experimental confirmation of this novel approach is reported, based on already published NMR data for a single crystal of methylmalonic acid. The once extensively debated issues of quenching of the coherent tunneling and of the classical limit in the dynamics of the methyl groups are readdressed and presented in a consistent manner.
Exact Green function for a Dirac particle in a weak gravitational plane wave field. Alternative path integral approach
Authors: Ould-Lahoucine H. K. , Chetouani L.
Published: July 2012

The exact Green function for a Dirac particle in interaction with a weak gravitational plane wave field is obtained throughout an alternative path integral approach. In addition, a canonical transformation is obtained so that the generating function is showed to be a solution to the Hamilton-Jacobi equation for spin zero particle.
Steady-state fluctuations of a genetic feedback loop: An exact solution
Authors: Grima R. , Schmidt D. R. , Newman T. J.
Published: July 2012

Genetic feedback loops in cells break detailed balance and involve bimolecular reactions; hence, exact solutions revealing the nature of the stochastic fluctuations in these loops are lacking. We here consider the master equation for a gene regulatory feedback loop: a gene produces protein which then binds to the promoter of the same gene and regulates its expression. The protein degrades in its free and bound forms. This network breaks detailed balance and involves a single bimolecular reaction step. We provide an exact solution of the steady-state master equation for arbitrary values of the parameters, and present simplified solutions for a number of special cases. The full parametric dependence of the analytical non-equilibrium steady-state probability distribution is verified by direct numerical solution of the master equations. For the case where the degradation rate of bound and free protein is the same, our solution is at variance with a previous claim of an exact solution [J. E. M. Hornos, D. Schultz, G. C. P. Innocentini, J. Wang, A. M. Walczak, J. N. Onuchic, and P. G. Wolynes, Phys. Rev. E 72, 051907 (2005)10.1103/PhysRevE.72.051907, and subsequent studies]. We show explicitly that this is due to an unphysical formulation of the underlying master equation in those studies.
Topological aspects of fermions on hyperdiamond
Authors: Saidi E. H. , Fassi-Fehri O. , Bousmina M.
Published: July 2012

Motivated by recent results on the index of the Dirac operator D = γμDμ of QCD on lattice and also by results on topological features of electrons and holes of two-dimensional graphene, we compute in this paper the index of D for fermions living on a family of even-dimensional lattices denoted as \documentclass[12pt]{minimal}\begin{document}$\mathbb {L}_{2N}$\end{document}L2N and describing the 2N-dimensional generalization of the graphene honeycomb. The calculation of this topological index is done by using the direct method based on solving explicitly the gauged Dirac equation and also by using specific properties of the lattices \documentclass[12pt]{minimal}\begin{document}$\mathbb {L} _{2N}$\end{document}L2N, which are shown to be intimately linked with the weight lattices of SU(2N + 1). The index associated with the two leading N = 1 and N = 2 elements of this family describe precisely the chiral anomalies of graphene and QCD4. Comments on the method using the spectral flow approach as well as the computation of the topological charges on 2-cycles of 2N-dimensional compact supercell in \documentclass[12pt]{minimal}\begin{document}$\mathbb {L}_{2N}$\end{document}L2N and applications to QCD4 are also given.
Mathematical and computational aspects of quaternary liquid mixing free energy measurement using light scattering
Authors: Wahle Chris W. , Ross David S. , Thurston George M.
Published: July 2012

We provide a mathematical and computational analysis of light scattering measurement of mixing free energies of quaternary isotropic liquids. In previous work, we analyzed mathematical and experimental design considerations for the ternary mixture case [D. Ross, G. Thurston, and C. Lutzer, J. Chem. Phys. 129, 064106 (2008)10.1063/1.2937902; C. Wahle, D. Ross, and G. Thurston, J. Chem. Phys. 137, 034201 (2012)10.1063/1.4731694]. Here, we review and introduce dimension-free general formulations of the fully nonlinear partial differential equation (PDE) and its linearization, a basis for applying the method to composition spaces of any dimension, in principle. With numerical analysis of the PDE as applied to the light scattering implied by a test free energy and dielectric gradient combination, we show that values of the Rayleigh ratio within the quaternary composition tetrahedron can be used to correctly reconstruct the composition dependence of the free energy. We then extend the analysis to the case of a finite number of data points, measured with noise. In this context the linearized PDE describes the relevant diffusion of information from light scattering noise to the free energy. The fully nonlinear PDE creates a special set of curves in the composition tetrahedron, collections of which form characteristics of the nonlinear and linear PDEs, and we show that the information diffusion has a time-like direction along the positive normals to these curves. With use of Monte Carlo simulations of light scattering experiments, we find that for a modest laboratory light scattering setup, about 100–200 samples and 100 s of measurement time are enough to be able to measure the mixing free energy over the entire quaternary composition tetrahedron, to within an \documentclass[12pt]{minimal}\begin{document}$\mathcal {L}_2$\end{document}L2 error norm of 10−3. The present method can help quantify thermodynamics of quaternary isotropic liquid mixtures.
Comment on some results of Erdahl and the convex structure of reduced density matrices
Authors: Chen Jianxin , Ji Zhengfeng , Ruskai Mary Beth , Zeng Bei , Zhou Duan-Lu
Published: July 2012

In [J. Math. Phys. 13, 1608–1621 (1972)], Erdahl10.1063/1.1665885 considered the convex structure of the set of N-representable 2-body reduced density matrices in the case of fermions. Some of these results have a straightforward extension to the m-body setting and to the more general quantum marginal problem. We describe these extensions, but cannot resolve a problem in the proof of Erdahl's claim that every extreme point is exposed in finite dimensions. Nevertheless, we can show that when 2m ⩾ N every extreme point of the set of N-representable m-body reduced density matrices has a unique pre-image in both the symmetric and anti-symmetric setting. Moreover, this extends to the quantum marginal setting for a pair of complementary m-body and (N − m)-body reduced density matrices.
Phase assembly and photo-induced current in CdTe-ZnO nanocomposite thin films
Authors: Beal R. J. , Kana Kana J. B. , Potter B. G.
Published: July 2012

Sequential radio-frequency sputtering was used to produce CdTe-ZnO nanocomposite thin films with varied semiconductor-phase extended structures. Control of the spatial distribution of CdTe nanoparticles within the ZnO embedding phase was used to influence the semiconductor phase connectivity, contributing to both changes in quantum confinement induced spectral absorption and carrier transport characteristics of the resulting nanocomposite. An increased number density of CdTe particles deposited along the applied field direction produced an enhancement in the photo-induced current observed. These results highlight the opportunity to employ long-range phase assembly as a means to control optoelectronic properties of significant interest for photovoltaic applications.
Plasma density measurements in tungsten wire-array Z-pinches
Authors: Douglass J. D. , Hammer D. A. , Pikuz S. A. , Shelkovenko T. A. , Blesener K. S.
Published: July 2012

Measurements of the plasma density profile near the exploding wires in 1 MA tungsten (W) wire-array Z-pinches have been made using calibrated x-ray absorption. As many as 5 x-ray images per pulse were obtained between 65 and 160 ns after the start of the 100 ns rise time current pulse. Measured W ion densities range from above 1019/cm3 close to the wire to ∼1017/cm3 about 1 mm away from the wire in the plasma stream. After accurate geometrical registration of the individual wires in each successive image in a pulse using the Genetic Algorithm, the temporal evolution of the axial modulation wavelength distribution of the ablation rate from the wires in each array and the global mass-ablation rate as a function of time are presented.
Pressure induced amorphization of ZrMo2O8 and its relaxation on decompression as seen by in situ total x-ray scattering
Authors: Wilkinson Angus P. , Greve Benjamin K. , Ruschman Chad J. , Chapman Karena W. , Chupas Peter J.
Published: July 2012

The pressure induced amorphization of the negative thermal expansion material cubic ZrMo2O8 was examined in situ within a diamond anvil cell, using high energy x-ray total scattering, during compression up to ∼7.2 GPa, and then decompressed. The amorphization upon compression was largely complete by ∼3 GPa. There was significant, but not complete, structural relaxation of the amorphous material on decompression; the pair distribution function (PDF) for the material recovered from 7.2 GPa closely resembled that for the sample during initial compression at ∼5.5 GPa. The PDFs indicated that the amorphization, densification, and relaxation of the amorphous solid involve changes in the first coordination shell of molybdenum and the creation/loss of Mo-O-M bridges with ∼3.4 Å Mo-M separation (M–Mo or Zr).
Electrical properties of the graphitic carbon contacts on carbon nanotube field effect transistors
Authors: Tamaoki Masato , Kishimoto Shigeru , Ohno Yutaka , Mizutani Takashi
Published: July 2012

Carbon nanotube field effect transistors (CNT-FETs) with graphitic carbon (G-C) contacts were fabricated and the electrical properties of the G-C contacts were studied. The CNT-FETs showed p-type conduction in air. However, the conduction type has changed to ambipolar in vacuum after annealing at 200 °C. This suggests that the p-type conduction in air is attributed to the adsorbed oxygen. The barrier heights at the G-C/CNT contacts in vacuum were ∼400 meV for electrons and ∼310 meV for holes. These values suggest that the Fermi level of G-C contacts is located at slightly below the midgap of the CNTs in vacuum.
30-kV spin-polarized transmission electron microscope with GaAs–GaAsP strained superlattice photocathode
Authors: Kuwahara M. , Kusunoki S. , Jin X. G. , Nakanishi T. , Takeda Y. , Saitoh K. , Ujihara T. , Asano H. , Tanaka N.
Published: July 2012

A spin-polarized electron beam has been used as the probe beam in a transmission electron microscope by using a photocathode electron gun with a photocathode made of a GaAs–GaAsP strained superlattice semiconductor with a negative electron affinity (NEA) surface. This system had a spatial resolution of the order of 1 nm for at 30 keV and it can generate an electron beam with an energy width of 0.24 eV without employing monochromators. This narrow width suggests that a NEA photocathode can realize a high energy resolution in electron energy-loss spectroscopy and a longitudinal coherence of 3 × 10−7 m.
Thermodynamic bounds on nonlinear electrostatic perturbations in intense charged particle beams
Authors: Logan Nikolas C. , Davidson Ronald C.
Published: July 2012

This paper places a lowest upper bound on the field energy in electrostatic perturbations in single-species charged particle beams with initial temperature anisotropy (T∥/T⊥<1). The result applies to all electrostatic perturbations driven by the natural anisotropies that develop in accelerated particle beams, including Harris-type electrostatic instabilities, known to limit the luminosity and minimum spot size attainable in experiments. The thermodynamic bound on the field perturbation energy of the instabilities is obtained from the nonlinear Vlasov-Poisson equations for an arbitrary initial distribution function, including the effects of intense self-fields, finite geometry, and nonlinear processes. This paper also includes analytical estimates of the nonlinear bounds for space-charge-dominated and emittance-dominated anisotropic bi-Maxwellian distributions.
Kinetic Alfven double layer formed by electron viscosity
Authors: Woo M. H. , Ryu C.-M. , Choi C. R.
Published: July 2012

The effect of the electron viscosity on the kinetic Alfven solitary wave is investigated. It is found that small electron viscosity changes the electron motion along the magnetic field producing a boundary layer, and thus that in a low beta electron-ion plasma(β≪me/mi), an obliquely propagating kinetic solitary Alfven wave can become a double layer. This double layer can exist in the sub-Alfvenic and super-Alfvenic regimes. The length scale of density drop for this double layer is on the order of that of the conventional kinetic solitary Alfven wave, and thus this double layer can accelerate electrons on a very short length scale.
Nanofocusing enhancement in a tapered slit by using a dielectric micro isosceles triangle prism and tuning the entrance aperture
Authors: Kuang Dengfeng , Ouyang Sheng , Du Zhongxun
Published: July 2012

We present a combined configuration consisting of a dielectric micro isosceles triangular prism and a metallic tapered slit for enhanced nanofocusing. The dielectric micro isosceles triangular prism collects the incident light first and then the tapered slit guides the beam to form naofocusing with higher intensity at the exit aperture of the tapered slit, which overcomes the limit of the extremely small entrance aperture diaphragm of the slit. With the help of the dielectric micro isosceles triangular prism, the intensity of the nanofocused electric field at the exit aperture of the tapered slit can be increased more than 4 folds.
Snap-in dynamics of single particles to water drops
Authors: Chen Longquan , Heim Lars-Oliver , Golovko Dmytro S. , Bonaccurso Elmar
Published: July 2012

The interaction between solid particles and gas-liquid interfaces is relevant in technological applications. Former studies did focus on detachment-dynamics of particles from thin liquid films or on attachment-dynamics of particles to gas bubbles. Here, we investigated snap-in dynamics of individual micron-sized particles to water drops by means of the colloidal probe technique. The snap-in time (∼0.1 ms) and the snap-in force of hydrophilic and hydrophobic particles were measured. The snap-in time increased with particle size regardless of wettability. The snap-in force increased with particle size and wettability. We show that the snap-in dynamics is dominated by capillarity and inertia.
One-dimensional stringlike cooperative migration of lithium ions in an ultrafast ionic conductor
Authors: Xu M. , Ding J. , Ma E.
Published: July 2012

In the recently developed ultrafast Li-ion conductor, Li10GeP2S12, our ab initio and molecular dynamics simulations have revealed a unique Li ion transport mechanism. The Li ions are discovered to migrate in a highly correlated fashion, stemming from the large Coulombic interaction between the mobile ions. The stringlike cooperative ionic motion is found to entail a rather low energy barrier, contributing to the unusually high ionic conductivity of this solid-state electrolyte. Such a collective migration mechanism may also be operative in other Li-ion battery electrolytes with high concentrations of mobile Li ions.
Characterization of vacancy-type defects in heteroepitaxial GaN grown by low-energy plasma-enhanced vapor phase epitaxy
Authors: Calloni A. , Ferragut R. , Dupasquier A. , von Känel H. , Guiller A. , Rutz A. , Ravelli L. , Egger W.
Published: July 2012

The defect concentration in thin GaN layers was estimated by means of positron annihilation spectroscopy. Positron lifetime and Doppler broadening of the annihilation radiation were used. A comparative study of GaN films grown with different techniques was performed. Specific attention has been given to the new low energy plasma enhanced vapor phase epitaxy (LEPEVPE) growth technique. A very high Ga vacancy density (1019 cm−3) was found in a thin GaN layer directly grown by LEPEVPE on a sapphire substrate. However, when a GaN substrate (commercial sample grown by Metal Organic Vapor Phase Epitaxy) is used as a template for LEPEVPE deposition, the vacancy density of the film is low (about 1016 cm−3). This fact provides evidences that the LEPEVPE technique is able to produce high quality GaN layers.
Synthesis of graphene-based Pt nanoparticles by a one-step in situ plasma approach under mild conditions
Authors: Wang Qi , Song Mingming , Chen Changlun , Wei Yu , Zuo Xiao , Wang Xiangke
Published: July 2012

Herein, a one-step in situ plasma approach to synthesize the highly dispersed Pt nanoparticles on graphene under mild conditions is reported. The graphene oxide (GO) was transformed into graphene and H2PtCl6 was simultaneously transformed into Pt nanoparticles under argon plasma conditions. The synthesized graphene-based Pt nanoparticles were characterized by scanning electron microscopy, atomic force microscopy, x-ray diffraction, and Fourier transform infrared spectroscopy. The analysis showed that the Pt nanoparticles were deposited on graphene as a form of face-centered cubical structure and the oxygen groups on graphene oxide were partially removed. The results of x-ray photoelectron spectroscopy analysis further confirmed the results.
Influence of alloy inhomogeneities on the determination by Raman scattering of composition and strain in Si1–xGex/Si(001) layers
Authors: Reparaz J. S. , Marcus I. C. , Goñi A. R. , Garriga M. , Alonso M. I.
Published: July 2012

In this work, we investigate the influence of alloy composition inhomogeneities on the vibrational properties of strained Si1−xGex/Si layers with x ranging from 0 to 0.5. We show that the frequencies of the principal alloy vibrational modes (Ge-Ge, Si-Ge, and Si-Si) are strongly influenced by the distribution of Ge atoms within the alloy layers, which becomes gradually random following a series of sequential annealing steps. Our measurements suggest that the composition dependence of the optical phonon frequencies in fully random and unstrained alloys is well described by the results previously published by Alonso and Winer [Phys. Rev. B 39, 10056 (1989)]. In the general case of an alloy layer with unknown degree of compositional inhomogeneity and/or strain relaxation, though the analysis of the Raman spectra is not straightforward. Therefore, we propose an analytical/graphical method to accurately estimate the Ge content and residual strain of SiGe layers exhibiting any level of compositional disorder or strain status, by performing a single Raman measurement. This would be extremely useful in situations where x-ray measurements cannot be conducted. We show that our procedure to treat the Raman data holds for the whole compositional range but with different accuracy depending upon the case: (i) For annealed SiGe layers (mostly strain relaxed) the Ge content x can be directly determined with high accuracy of ±0.01. (ii) For strained samples (usually as-grown samples) an extra criterion must be adopted seeking for a graphical solution, accounting for the degree of compositional inhomogeneity. In this case, the error in the determination of Ge content depends on alloy composition, being the upper bound ±0.02 for x<0.3 and ±0.03 for x>0.3.
Transport in the plateau regime in a tokamak pedestal
Authors: Seol J. , Shaing K. C.
Published: July 2012

In a tokamak H-mode, a strong E × B flow shear is generated during the L-H transition. Turbulence in a pedestal is suppressed significantly by this E × B flow shear. In this case, neoclassical transport may become important. The neoclassical fluxes are calculated in the plateau regime with the parallel plasma flow using their kinetic definitions. In an axisymmetric tokamak, the neoclassical particles fluxes can be decomposed into the banana-plateau flux and the Pfirsch-Schlüter flux. The banana-plateau particle flux is driven by the parallel viscous force and the Pfirsch-Schlüter flux by the poloidal variation of the friction force. The combined quantity of the radial electric field and the parallel flow is determined by the flux surface averaged parallel momentum balance equation rather than requiring the ambipolarity of the total particle fluxes. In this process, the Pfirsch-Schlüter flux does not appear in the flux surface averaged parallel momentum equation. Only the banana-plateau flux is used to determine the parallel flow in the form of the flux surface averaged parallel viscosity. The heat flux, obtained using the solution of the parallel momentum balance equation, decreases exponentially in the presence of sonic Mp without any enhancement over that in the standard neoclassical theory. Here, Mp is a combination of the poloidal E × B flow and the parallel mass flow. The neoclassical bootstrap current in the plateau regime is presented. It indicates that the neoclassical bootstrap current also is related only to the banana-plateau fluxes. Finally, transport fluxes are calculated when Mp is large enough to make the parallel electron viscosity comparable with the parallel ion viscosity. It is found that the bootstrap current has a finite value regardless of the magnitude of Mp.