bluuebunny/crossref_metadata_2025 huggingface dataset:
Age of onset group characteristics in forensic patients with schizophrenia
Authors: Vinokur D. , Levine S.Z. , Roe D. , Krivoy A. , Fischel T.
Published: February 2013

This study aims to empirically identify age of onset groups and their clinical and background characteristics in forensic patients with schizophrenia. Hospital charts were reviewed of all 138 forensic patients with schizophrenia admitted to Geha Psychiatric Hospital that serves a catchment area of approximately 500,000 people, from 2000 to 2009 inclusive. Admixture analysis empirically identified early- (M = 19.99, SD = 3.31) and late-onset groups (M = 36.13, SD = 9.25). Early-onset was associated with more suicide attempts, violence before the age of 15, and early conduct problems, whereas late-onset was associated with a greater likelihood of violence after the age of 18 and marriage (P < 0.01). The current findings provide clinicians with a unique direction for risk assessment and indicate differences in violence between early- and late-onset schizophrenia, particularly co-occurrence of harmful behavioral phenotypes.
Factors associated with borderline personality disorder in major depressive patients and their relationship to bipolarity
Authors: Azorin J.M. , Kaladjian A. , Adida M. , Fakra E. , Belzeaux R. , Hantouche E. , Lancrenon S.
Published: February 2013

Objective

To analyze the interface between borderline personality disorder (BPD) and bipolarity in depressed patients comorbid with BPD.

Methods

As part of National Multi-site Study of 493 consecutive DSM-IV major depressive patients evaluated in at least two semi-structured interviews 1 month apart, 19 (3.9%) had comorbid BPD (BPD+), whereas 474 (96.1%) did not manifest this comorbidity (BPD−).

Results

Compared to BPD (−), BPD (+) patients displayed higher rates of bipolar (BP) disorders and temperaments, an earlier age at onset with a family history of affective illness, more comorbidity, more stressors before the first episode which was more often depressive or mixed, as well as a greater number and severity of affective episodes.

Conclusions

The hypothesis which fitted at best our findings was to consider BPD as a contributory factor in the development of BP disorder, which could have favoured the progression from unipolar major depression to BP disorder. We could not however exclude that some features of BP disorder may have contributed to the development of BPD.
Diabetes mellitus, metabolic syndrome and obesity are not significant risk factors for hepatocellular carcinoma in an HBV‐ and HCV‐endemic area of Southern Taiwan
Authors: Chen Chao‐Tung , Chen Jing‐Yi , Wang Jing‐Houng , Chang Kuo‐Chin , Tseng Po‐Lin , Kee Kwong‐Ming , Chen Pao‐Fei , Tsai Lin‐San , Chen Shu‐Chuan , Lin Sheng‐Che , Lu Sheng‐Nan
Published: February 2013

A prominent factor in hepatocellular carcinoma (HCC) is chronic infection with hepatitis B virus (HBV) and hepatitis C virus (HCV). Diabetes mellitus (DM), metabolic syndrome (MetS), and obesity have also been implicated in HCC development, but these associations are not observed in all HBV‐ and HCV‐endemic areas. We attempted to clarify the role of these factors in HCC development in an HBV‐ and HCV‐endemic area in southern Taiwan. A community‐based health examination was conducted in 2004 in Tainan County. After individuals with incomplete data and those with known HCC were excluded, there were 56,231 participants who were over 40 years of age. A further 262 HCC cases were identified from the National Cancer Registration Database records from 2005 to 2007. The hepatitis B surface antigen (HBsAg) seropositivity, anti‐HCV seropositivity, platelet count, serum biochemical data, blood pressure, sociodemographic information, and anthropometric measurements were analyzed. Survival analyses were used to identify the associations between these factors and HCC. For the 262 HCC cases, male gender and age greater than 65 years were risk factors. Furthermore, a high alanine aminotransferase level, chronic HBV and/or HCV infection, and liver cirrhosis were also risk factors for HCC. However, DM, MetS and obesity were not associated with HCC development in the non‐HBV‐/non‐HCV‐infected, HBV, HCV, or dual B/C groups. In this HBV‐ and HCV‐ endemic area, DM, MetS and obesity were not risk factors for developing HCC.
Outcomes After Ultrasound‐Guided Platelet‐Rich Plasma Injections for Chronic Tendinopathy: A Multicenter, Retrospective Review
Authors: Mautner Kenneth , Colberg Ricardo E. , Malanga Gerard , Borg‐Stein Joanne P. , Harmon Kimberly G. , Dharamsi Aisha S. , Chu Samuel , Homer Paul
Published: February 2013

Objective

To determine whether ultrasound‐guided platelet‐rich plasma (PRP) injections are an effective treatment for chronic tendinopathies.

Design

A retrospective, cross‐sectional survey.

Setting

Four academic sports medicine centers from across the United States.

Patients

A total of 180 men and women between the ages of 18 and 75 years who received ultrasound‐guided PRP injections for tendinopathy refractory to conventional treatments.

Interventions

Survey on satisfaction and functional outcome.

Main Outcome Measurements

Perceived improvement in symptoms at least 6 months after treatment, perceived change in visual analog scale score, assessment of functional pain, and overall satisfaction.

Results

On average, patients were 48 years old, had symptoms for a median of 18 months before treatment, and answered the survey on average 15 months after treatment. Overall, 82% of patients indicated moderate to complete improvement in symptoms. The most common injection sites were the lateral epicondyle, Achilles, and patellar tendons. Other sites treated included the rotator cuff, hamstring, gluteus medius, and medial epicondyle, among others. Furthermore, 60% of patients received only 1 injection, 30% received 2 injections, and 10% received 3 or more injections. Patients' perceived decrease in visual analog scale score was 75%, from 7.0 ± 1.8 to 1.8 ± 2.0 (−5.2, SD 2.7, 95% confidence interval −5.65 to −4.86, P < .0001). In addition, at follow‐up, 95% of patients reported having no pain at rest that disrupted their activities of daily living and 68% reported no pain during activities. A total of 85% of patients were satisfied with the procedure.

Conclusions

In this retrospective study, in which we evaluated administration of PRP for chronic tendinopathy, we found that the majority of patients reported a moderate (>50%) improvement in pain symptoms.
A Simple Technique to Restore Needle Patency During Percutaneous Lavage and Aspiration of Calcific Rotator Cuff Tendinopathy
Authors: Jelsing Elena J. , Maida Eugene , Smith Jay
Published: February 2013

Calcific rotator cuff tendinopathy caused by symptomatic calcium hydroxyapatite crystal deposition is a well‐established cause of shoulder pain. In refractory or acutely symptomatic cases, sonographically guided percutaneous lavage and aspiration can significantly reduce pain in approximately 60%‐92% of cases. Although the complication rate of sonographically guided percutaneous lavage and aspiration is apparently low, needle clogging attributable to impacted calcific debris has been described by several authors and in our experience can occur in daily practice. Traditionally, an inability to relieve the obstruction via needle repositioning or increased syringe plunger pressure has required needle removal and replacement. In this article, we outline a simple technique that can be used to restore patency of the obstructed lavage needle without necessitating needle removal and replacement.
Quality of Life and Functionality of Patients With Heel Reconstruction After Landmine Explosions
Authors: Tekin Levent , Zor Fatih , Akarsu Selim , Tuncer Salim Kemal , Öztürk Sinan , Öztürk Serdar
Published: February 2013

Background

Landmine injuries cause extensive soft and bony tissue loss of the weight‐bearing areas, particularly the heel. Reconstruction of these injuries is challenging, and there are no studies that report long‐term functional results.

Objective

To determine the quality of life and long‐term functionality of patients who had heel reconstruction with free muscle flap after landmine injuries.

Design

A case‐control study.

Participants

Nine male patients who had heel reconstruction with free muscle flap. Ten male volunteers without any gait disorder were included in the study as the control group.

Methods and Interventions

Functional ambulation scale, visual analog scale, energy expenditure index, 6‐minute walking test, 10‐m walking test, and Short Form 36 were performed to determine the quality of life and functionality of the participants.

Results

There were no statistically significant differences between the 2 groups in terms of functional ambulation scale, energy expenditure index, 6‐minute walking test, and 10‐m walking test. Regarding Short Form 36 scores, all subgroup values were lower in the reconstruction group, whereas only those of general health, vitality, and physical‐emotional role limitation subgroups showed statistical significance. Mean visual analog scale scores were found to be statistically different between the groups (P < .05). Mean Freiburg Ankle scores showed moderate functionality.

Conclusion

Despite the associated physical and emotional trauma, combat‐injured veterans with heel reconstruction after landmine injuries had adequate and functional ambulation at long‐term follow‐up. Early rehabilitation and close cooperation between surgeons and rehabilitation physicians during the care of these patients will enhance patient outcomes.
Discourse and strategic continuity from Gorbachev through Putin
Authors: Anderson Richard D.
Published: February 2013

Discourse analysis reveals that Mikhail Gorbachev as General Secretary and his successors as Russian presidents have practiced a shared strategy of metaphorical – not spatial – centrism that has gradually slid the state from dictatorship toward democracy. Preservation of a political center for himself and his successors to occupy made it necessary for Boris Yeltsin to dismantle the USSR if elections in Russia were to continue. At the same time, for each successive exponent of this centrist strategy, an attempt to practice democracy without the repellent flaws of electoral fraud and political repression would forgo the strategic advantage of occupying the political center.
Can habit formation under complete market integration explain the cross‐section of international equity risk premia?
Authors: Auer Benjamin R.
Published: February 2013

In this article, we analyse whether the prominent habit formation model ofCampbell and Cochrane (1999)can explain the cross‐section of the G7 equity risk premia when formulated under the assumption of complete capital market integration. We test the conditional covariance representation of the model using a combined GARCH and GMM approach in the spirit ofBali (2008)and find that in comparison to the CAPM and the standard power utility CCAPM the habit model has superior explanatory power. It explains more than 90% of the cross‐sectional variation in risk premia. Overall, our findings suggest that global consumption‐based recession indicators and not returns of reference portfolios are key risk factors driving equity risk premia.
Applicability of Nigeria's Arbitration and Conciliation Act: Which Field Does the Act Cover?
Authors: Ikeyi Nduka , Amucheazi Ofornze
Published: February 2013

In 1988, Nigeria's Federal Military Government promulgated the Arbitration and Conciliation Decree (now the Arbitration and Conciliation Act) to provide a unified legal framework for commercial arbitration throughout Nigeria. At the time of the decree's promulgation, the Federal Military Government had unlimited competence to legislate over any matter in, and for all parts of, Nigeria. However, under Nigeria's current constitutional democracy and federal structure of government, legislative powers are shared between the Federal Government and the respective state governments. This article investigates the constitutionality of the continued application of the Arbitration and Conciliation Act as federal legislation with application in all states of the federation.
The Strong and Weak Senses of Theory-Ladenness of Experimentation: Theory-Driven versus Exploratory Experiments in the History of High-Energy Particle Physics
Authors: Karaca Koray
Published: February 2013

Argument

In the theory-dominated view of scientific experimentation, all relations of theory and experiment are taken on a par; namely, that experiments are performed solely to ascertain the conclusions of scientific theories. As a result, different aspects of experimentation and of the relations of theory to experiment remain undifferentiated. This in turn fosters a notion of theory-ladenness of experimentation (TLE) that is toocoarse-grainedto accurately describe the relations of theory and experiment in scientific practice. By contrast, in this article, I suggest that TLE should be understood as anumbrella conceptthat has different senses. To this end, I introduce a three-fold distinction among the theories of high-energy particle physics (HEP) as background theories, model theories, and phenomenological models. Drawing on this categorization, I contrast two types of experimentation, namely, “theory-driven” and “exploratory” experiments, and I distinguish between the “weak” and “strong” senses of TLE in the context of scattering experiments from the history of HEP. This distinction enables identifying the exploratory character of the deep-inelastic electron-proton scattering experiments – performed at the Stanford Linear Accelerator Center (SLAC) between the years 1967 and 1973 – thereby shedding light on a crucial phase of the history of HEP, namely, the discovery of “scaling,” which was the decisive step towards the construction of quantum chromo-dynamics as a gauge theory of strong interactions.
Introducing Applied Legal History
Authors: Brophy Alfred L.
Published: February 2013

James Oldham and Su Jin Kim write about the acceptance of arbitration in the early United States in their article, “Arbitration in America: The Early History.” They correct a misperception that stretches back at least to Justice Joseph Story's 1844 opinion inTobey v. Bristolthat said equity did not enforce arbitration awards. Oldham and Kim recover a robust culture of arbitration in the early United States and thus correct the received wisdom, which led Justice Kennedy to remark in 2001 that American courts were historically hostile to arbitration. Perhaps this newly recovered history will add support for the acceptance of arbitration in the federal courts. Oldham's and Kim's article is, therefore, part of an emerging and sometimes controversial trend in legal history to speak to contemporary issues. It is also the first of an occasional series forLaw and History Reviewon “applied legal history.”
Arbitration in America: The Early History
Authors: Oldham James , Kim Su Jin
Published: February 2013

On June 29, 1789, Zephaniah Turner of Charles County, Maryland, wrote to President George Washington and observed:

Our Laws are too Numerous. Is it not possible that an alteration might take place for the benefit of the public?…Could it not be possible to curtail the Number of Lawyers in the different States? Suppose each State was to have but Two Lawyers to be paid liberally…[and] where a real dispute subsisted between Plaintiff and Defendant a reference [to arbitration] should be proposed, and arbitrators [be] indifferently chosen by both parties…whose determination shall be final.
The impact of viral tropism and housing conditions on the transmission of three H5/H7 low pathogenic avian influenza viruses in chickens
Authors: CLAES G. , WELBY S. , VAN DEN BERG T. , VAN DER STEDE Y. , DEWULF J. , LAMBRECHT B. , MARCHÉ S.
Published: February 2013

In this study, shedding and transmission of three H5/H7 low pathogenic avian influenza viruses (LPAIVs) in poultry was characterized and the impact of floor system on transmission was assessed. Transmission experiments were simultaneously conducted with two groups of animals housed on either a grid or a floor covered with litter. Transmission was observed for H5N2 A/Ch/Belgium/150VB/99 LPAIV. This virus was shed almost exclusively via the oropharynx and no impact of floor system was seen. Transmission was also seen for H7N1 A/Ch/Italy/1067/v99 LPAIV, which was shed via both the oropharynx and cloaca. A slight increase in transmission was seen for animals housed on litter. H5N3 A/Anas Platyrhynchos/Belgium/09-884/2008 LPAIV did not spread to susceptible animals, regardless of the floor system. This study shows that environmental factors such as floor systems used in poultry barns may act upon the transmission of LPAIVs. However, the level of influence depends on the virus under consideration and, more specifically, its principal replication sites.
Using complementary methods to test whether marriage limits men's antisocial behavior
Authors: Jaffee Sara R. , Lombardi Caitlin McPherran , Coley Rebekah Levine
Published: February 2013

Married men engage in significantly less antisocial behavior than unmarried men, but it is not clear whether this reflects a causal relationship. Instead, the relationship could reflect selection into marriage whereby the men who are most likely to marry (men in steady employment with high levels of education) are the least likely to engage in antisocial behavior. The relationship could also be the result of reverse causation, whereby high levels of antisocial behavior are a deterrent to marriage rather than the reverse. Both of these alternative processes are consistent with the possibility that some men have a genetically based proclivity to become married, known as an active genotype–environment correlation. Using four complementary methods, we tested the hypothesis that marriage limits men's antisocial behavior. These approaches have different strengths and weaknesses and collectively help to rule out alternative explanations, including active genotype–environment correlations, for a causal association between marriage and men's antisocial behavior. Data were drawn from the in-home interview sample of the National Longitudinal Study of Adolescent Health, a large, longitudinal survey study of a nationally representative sample of adolescents in the United States. Lagged negative binomial and logistic regression and propensity score matching models (n = 2,250), fixed-effects models of within-individual change (n = 3,061), and random-effects models of sibling differences (n = 618) all showed that married men engaged in significantly less antisocial behavior than unmarried men. Our findings replicate results from other quasiexperimental studies of marriage and men's antisocial behavior and extend the results to a nationally representative sample of young adults in the United States.
Handedness and corpus callosal morphology in Williams syndrome
Authors: Martens Marilee A. , Wilson Sarah J. , Chen Jian , Wood Amanda G. , Reutens David C.
Published: February 2013

Williams syndrome is a neurodevelopmental genetic disorder caused by a hemizygous deletion on chromosome 7q11.23, resulting in atypical brain structure and function, including abnormal morphology of the corpus callosum. An influence of handedness on the size of the corpus callosum has been observed in studies of typical individuals, but handedness has not been taken into account in studies of callosal morphology in Williams syndrome. We hypothesized that callosal area is smaller and the size of the splenium and isthmus is reduced in individuals with Williams syndrome compared to healthy controls, and examined age, sex, and handedness effects on corpus callosal area. Structural magnetic resonance imaging scans were obtained on 25 individuals with Williams syndrome (18 right-handed, 7 left-handed) and 25 matched controls. We found that callosal thickness was significantly reduced in the splenium of Williams syndrome individuals compared to controls. We also found novel evidence that the callosal area was smaller in left-handed participants with Williams syndrome than their right-handed counterparts, with opposite findings observed in the control group. This novel finding may be associated with LIM-kinase hemizygosity, a characteristic of Williams syndrome. The findings may have significant clinical implications in future explorations of the Williams syndrome cognitive phenotype.
Explanation in Physics: Explanation in Physical Theory
Authors: Clark Peter
Published: February 2013

The corpus of physical theory is a paradigm of knowledge. The evolution of modern physical theory constitutes the clearest exemplar of the growth of knowledge. If the development of physical theory does not constitute an example of progress and growth in what we know about the Universe nothing does. So anyone interested in the theory of knowledge must be interested consequently in the evolution and content of physical theory. Crucial to the conception of physics as a paradigm of knowledge is the way in which physical theory provides explanations of a vast diversity of natural phenomena on the basis of a very few fundamental principles. A central problem for the epistemologist is therefore what is theoretical explanation in physics? Here we can get good insight from what Redhead has said (this volume pp. 145–54). Indeed one could agree with almost everything Redhead says and simply endorse much of his careful and extensive defence of the covering law account of explanation in the physical sciences at least as an ideal. However I shall, I fear, try the reader's patience by extending some of the considerations he introduced and raising those issues where we disagree, especially in the important area of statistical explanation.
Labiodental fronting of /θ/ in London and Edinburgh: a cross-dialectal study
Authors: SCHLEEF ERIK , RAMSAMMY MICHAEL
Published: February 2013

This study examines the lexical and grammatical diffusion of TH-fronting amongst adolescents in London, where TH-fronting is well established, and Edinburgh, where it is a relatively new phenomenon. Our results reveal that the application of TH-fronting is constrained in Edinburgh in ways that are not relevant for London, and vice versa. Specifically, whereas TH-fronting is sensitive to phonotactic context and prosodic position in Edinburgh, we observe no such effects amongst the London speakers. Morphological complexity, on the other hand, is a significant predictor of TH-fronting in both regions; however, we also find evidence of significant gender differences in the use of fronting in London that do not emerge in our Edinburgh data. We argue that these results attest to the more established nature of TH-fronting in London as compared to Edinburgh. We also address the question of how speech perception influences the emergence and spread of innovative neutralisation phenomena like TH-fronting. The results of this study further highlight the usefulness of a comparative variationist approach to understanding patterns of dialectal variation and change.
Mediating Effects of Coping Style on Associations Between Mental Health Factors and Self-Harm Among Adolescents
Authors: McMahon Elaine M. , Corcoran Paul , McAuliffe Carmel , Keeley Helen , Perry Ivan J. , Arensman Ella
Published: February 2013

Background: There is evidence for an association between suicidal behavior and coping style among adolescents. Aims: The aims of this study were to examine associations between coping style, mental health factors, and self-harm thoughts and acts among Irish adolescents, and to investigate whether coping style mediates associations between mental health factors (depression, anxiety, and self-esteem) and self-harm. Method: A cross-sectional school-based survey was carried out. Information was obtained on history of self-harm, life events, and demographic, psychological, and lifestyle factors. Results: Emotion-oriented coping was strongly associated with poorer mental health and self-harm thoughts and acts. Problem-Oriented Coping was associated with better mental health. Mediating effects of Emotion-Oriented Coping on associations between mental health factors and deliberate self-harm (DSH) was found for both genders and between Problem-Oriented Coping and mental health factors for girls. Similar mediating effects of coping style were found when risk of self-harm thoughts was examined. Limitations: Since the methodology used was cross-sectional, it is impossible to draw conclusions regarding causal relationships between coping style and associated factors. The coping measure used was brief. Conclusions: Promotion of positive coping skills and reduction of emotion-focused approaches may build resilience to self-harm thoughts and acts among adolescents experiencing mental health problems.
Calculating excited state properties using Kohn-Sham density functional theory
Authors: Hanson-Heine Magnus W. D. , George Michael W. , Besley Nicholas A.
Published: February 2013

The accuracy of excited states calculated with Kohn-Sham density functional theory using the maximum overlap method has been assessed for the calculation of adiabatic excitation energies, excited state structures, and excited state harmonic and anharmonic vibrational frequencies for open-shell singlet excited states. The computed Kohn-Sham adiabatic excitation energies are improved significantly by post self-consistent field spin-purification, but remain too low compared with experiment with a larger error than time-dependent density functional theory. Excited state structures and vibrational frequencies are also improved by spin-purification. The structures show a comparable accuracy to time-dependent density functional theory, while the harmonic vibrational frequencies are found to be more accurate for the majority of vibrational modes. The computed harmonic vibrational frequencies are also further improved by perturbative anharmonic corrections, suggesting a good description of the potential energy surface. Overall, excited state Kohn-Sham density functional theory is shown to provide an efficient method for the calculation of excited state structures and vibrational frequencies in open-shell singlet systems and provides a promising technique that can be applied to study large systems.
Electro-optical response of polymer-dispersed liquid crystal single layers of large nematic droplets oriented by rubbed teflon nanolayers
Authors: Marinov Y. G. , Hadjichristov G. B. , Petrov A. G. , Marino S. , Versace C. , Scaramuzza N.
Published: February 2013

The surface orienting effect of rubbed teflon nanolayers on the morphology and electro-optical (EO) response of polymer-dispersed liquid crystal (PDLC) single layers of large nematic droplets was studied experimentally. In PDLC composites of the nematic liquid crystal (LC) E7 and NOA65 polymer, single droplets of LC with diameters as larger as 10 μm were confined in layers with a thickness of 10 μm, and the nematic director field was efficiently modified by nanostructuring teflon rubbing of the glass plates of the PDLC cell. For layered PDLCs arranged and oriented in this way, the modulated EO response by the dielectric oscillations of the nematic director exhibits a selective amplitude-frequency modulation controllable by both temperature and voltage applied, and is simply related to the LC droplet size. That may be of practical interest for PDLC-based modulators operating in the infrasound frequency range.
Further details on the phase diagram of hard ellipsoids of revolution
Authors: Bautista-Carbajal Gustavo , Moncho-Jordá Arturo , Odriozola Gerardo
Published: February 2013

In recent work we revisited the phase diagram of hard ellipsoids of revolution (spheroids) by means of replica exchange Monte Carlo simulations. This was done by setting random initial configurations, and allows to confirm the formation of sm2 crystal structures at high densities [P. Pfleiderer and T. Schilling, Phys. Rev. E 75, 020402 (2007)10.1103/PhysRevE.75.020402] for large anisotropies and stretched-fcc for small anisotropies. In this work we employed the same technique but setting the starting cells as sm2 crystal structures having the maximum known packing density [A. Donev, F. H. Stillinger, P. M. Chaikin, and S. Torquato, Phys. Rev. Lett. 92, 255506 (2004)10.1103/PhysRevLett.92.255506]. This procedure yields a very rich behavior for quasi-spherical oblates and prolates. These systems, from low to high pressures, show the following phases: isotropic fluid, plastic solid, stretched-fcc solid, and sm2 solid. The first three transitions are first order, whereas the last one is a subtle, probably high order transition. This picture is consistent with the fact of having the sm2 structure capable of producing the maximally achievable density.
Reduced atomic pair-interaction design (RAPID) model for simulations of proteins
Authors: Ni Boris , Baumketner Andrij
Published: February 2013

Increasingly, theoretical studies of proteins focus on large systems. This trend demands the development of computational models that are fast, to overcome the growing complexity, and accurate, to capture the physically relevant features. To address this demand, we introduce a protein model that uses all-atom architecture to ensure the highest level of chemical detail while employing effective pair potentials to represent the effect of solvent to achieve the maximum speed. The effective potentials are derived for amino acid residues based on the condition that the solvent-free model matches the relevant pair-distribution functions observed in explicit solvent simulations. As a test, the model is applied to alanine polypeptides. For the chain with 10 amino acid residues, the model is found to reproduce properly the native state and its population. Small discrepancies are observed for other folding properties and can be attributed to the approximations inherent in the model. The transferability of the generated effective potentials is investigated in simulations of a longer peptide with 25 residues. A minimal set of potentials is identified that leads to qualitatively correct results in comparison with the explicit solvent simulations. Further tests, conducted for multiple peptide chains, show that the transferable model correctly reproduces the experimentally observed tendency of polyalanines to aggregate into β-sheets more strongly with the growing length of the peptide chain. Taken together, the reported results suggest that the proposed model could be used to succesfully simulate folding and aggregation of small peptides in atomic detail. Further tests are needed to assess the strengths and limitations of the model more thoroughly.
Negative magnetoresistance and anomalous Hall effect in GeMnTe-SnMnTe spin-glass-like system
Authors: Kilanski L. , Szymczak R. , Dobrowolski W. , Podgórni A. , Avdonin A. , Slynko V. E. , Slynko E. I.
Published: February 2013

Magnetotransport properties of spin-glass-like Ge1−x−ySnxMnyTe mixed crystals with chemical composition changing in the range of 0.083≤x≤0.142 and 0.012≤y≤0.119 are presented. The observed negative magnetoresistance we attribute to two mechanisms, i.e., weak localization occurring at low fields and spin disorder scattering giving contribution mainly at higher magnetic fields. A pronounced hysteretic anomalous Hall effect (AHE) was observed. The estimated AHE coefficient shows a small temperature dependence and is dependent on Mn-content, with changes in the range of 10−7<RS<10−6m3/C. The scaling law analysis has proven that the AHE in this system is due to the extrinsic mechanisms, mainly due to the skew scattering accompanied with the side jump processes.
Thiolate adsorption on Au(${\bm {hkl}}$hkl) and equilibrium shape of large thiolate-covered gold nanoparticles
Authors: Barmparis Georgios D. , Honkala Karoliina , Remediakis Ioannis N.
Published: February 2013

The adsorption of thiolates on Au surfaces employing density-functional-theory calculations has been studied. The dissociative chemisorption of dimethyl disulfide (CH3S−SCH3) on 14 different Au(hkl) is used as a model system. We discuss trends on adsorption energies, bond lengths, and bond angles as the surface structure changes, considering every possible Au(hkl) with h, k, l ⩽ 3 plus the kinked Au(421). Methanethiolate (CH3S-) prefers adsorption on bridge sites on all surfaces considered; hollow and on top sites are highly unfavourable. The interface tensions for Au(hkl)-thiolate interfaces is determined at low coverage. Using the interface tensions in a Wulff construction method, we construct atomistic models for the equilibrium shape of large thiolate-covered gold nanoparticles. Gold atoms in a nanoparticle change their equilibrium positions upon adsorption of thiolates towards shapes of higher sphericity and higher concentration of step-edge atoms.
Charge emissions from electrosprays in vacuum: Mixtures of formamide with methylammonium formate
Authors: Garoz David , Fernández de la Mora Juan
Published: February 2013

The charge/mass distribution f(q/m) of nanodrops and ions electrosprayed in vacuum from mixtures of formamide (FM) and methylammonium formate (MAF) is studied by time of flight mass spectrometry at MAF/FM volumetric concentrations of 5%, 10%, 25%, and 50%. Positive and negative polarities yield comparable f(q/m) curves, though the negative mode yields ∼30% larger currents. On shifting from the highest to the lowest liquid flow rates at which a cone-jet is stable, the more conductive solutions evolve from mostly drop to primarily ion emission. A purely ionic regime is not reached under any condition, but the drops achieve unusually high q/m. As a result, these sprays have excellent electrical propulsion characteristics, some being able to cover a 25-fold range of average q/m with a polydispersive efficiency typically in the range of 80%. Results of formamide electrolytes with formates and nitrates of several other amines are more briefly reported.
Effect of growth temperature and post-growth annealing on luminescence properties of molecular beam epitaxy grown single layer Ge quantum dots
Authors: Das S. , Manna S. , Singha R. K. , Aluguri R. , Ray S. K.
Published: February 2013

We report the detailed structural and luminescence properties of Si-embedded single layer Ge nanoislands grown via Stranski-Krastanov mechanism using molecular beam epitaxy. The luminescence energy peak positions correlated with structural properties have been studied as a function of the growth temperature and post-growth annealing. The photoluminescence peak for the annealed sample (500 °C grown) is blue shifted with increasing anneal temperature compared to the as grown sample due to intermixing of Si/Ge. Electroluminescence from the single layer Ge islands in the wavelength range 1.53 to 1.67 μm has been demonstrated using a metal-insulator-semiconductor structure, making it attractive for quantum dot light emitting devices.
Morphological evolution of InGaN/GaN light-emitting diodes grown on free-standing m-plane GaN substrates
Authors: Farrell R. M. , Haeger D. A. , Fujito K. , DenBaars S. P. , Nakamura S. , Speck J. S.
Published: February 2013

We report on the morphological evolution of InGaN/GaN light-emitting diodes (LEDs) grown on nominally on-axis and intentionally misoriented free-standing m-plane GaN substrates. Large variations in p-n junction depth (±175nm) were observed for LEDs grown on nominally on-axis substrates, while negligible variations in junction depth (±20 nm) were observed for LEDs grown on intentionally misoriented substrates. The surfaces of LEDs grown on the nominally on-axis substrates were characterized by the presence of a high density of pyramidal hillocks [Hirai et al., Appl. Phys. Lett. 91, 191906 (2007)], while the surfaces of the LEDs grown on the intentionally misoriented substrates were relatively smooth and free of pyramidal hillocks. Detailed measurements indicated that the variations in junction depth observed for LEDs grown on nominally on-axis substrates were related to an evolution in the shape of individual pyramidal hillocks during the growth of the LEDs. These results indicate that growing LEDs on intentionally misoriented substrates is an effective way to eliminate the pyramidal hillocks and variations in junction depth associated with growth on nominally on-axis substrates.
Relationship between the cell thickness and the optimum period of textured back reflectors in thin-film microcrystalline silicon solar cells
Authors: Sai Hitoshi , Saito Kimihiko , Hozuki Nana , Kondo Michio
Published: February 2013

Periodically textured back reflectors with hexagonal dimple arrays are applied to thin-film microcrystalline silicon (μc-Si:H) solar cells. When the textures have a moderate aspect ratio, the optimum period for obtaining a high short circuit current density (JSC) is found to be equal to or slightly larger than the cell thickness. If the cell thickness exceeds the texture period, the cell surface tends to be flattened and texture-induced defects are generated, which constrain the improvement in JSC. Based on these findings, we have fabricated optimized μc-Si:H cells achieving a high efficiency exceeding 10% and a JSC of 30 mA/cm2.
The role of octahedral tilting in the structural phase transition and magnetic anisotropy in SrRuO3 thin film
Authors: Lu Wenlai , Dong Song Wen , He Kaihua , Chai Jianwei , Sun Cheng-Jun , Chow Gan-Moog , Chen Jing-Sheng
Published: February 2013

We present a stoichiometry-dependent structural phase transition in SrRuO3 film on SrTiO3 substrate. The oxygen stoichiometry in the films was varied by changing the oxygen partial pressure P(O2) during the deposition process. For SrRuO3 films with P(O2) ≥ 60 mTorr, they exhibited a pseudo-orthorhombic structure with in-plane uniaxial magnetic anisotropy. On the other hand for films with P(O2) ≤ 45 mTorr, the tetragonal SrRuO3 phase with a perpendicular uniaxial magnetic anisotropy was stabilized at room temperature. The big difference in the magnetic anisotropy of these two SrRuO3 phases was shown to be closely linked to their respective RuO6 octahedral rotation patterns: the RuO6 octahedra rotate differently along the two orthogonal in-plane directions in the pseudo-orthorhombic phase, whereas in the tetragonal phase only octahedral rotations around z-axis are present and the octahedral tilts along the in-plane axes are diminished. First-principles calculations show that such a suppression of the RuO6 octahedra tilting in the tetragonal phase arises from the oxygen vacancies at the octahedral apex (along z-axis). This work demonstrates that the stoichiometry plays an important role in determining the octahedral rotations and tilts in the perovskite materials, which may induce new phases with distinctively different structural symmetry and physical property.
Joule heat generation in thermionic cathodes of high-pressure arc discharges
Authors: Benilov M. S. , Cunha M. D.
Published: February 2013

The nonlinear surface heating model of plasma-cathode interaction in high-pressure arcs is extended to take into account the Joule effect inside the cathode body. Calculation results are given for different modes of current transfer to tungsten cathodes of different configurations in argon plasmas of atmospheric or higher pressures. Special attention is paid to analysis of energy balances of the cathode and the near-cathode plasma layer. In all the cases, the variation of potential inside the cathode is much smaller than the near-cathode voltage drop. However, this variation can be comparable to the volt equivalent of the energy flux from the plasma to the cathode and then the Joule effect is essential. Such is the case of the diffuse and mixed modes on rod cathodes at high currents, where the Joule heating causes a dramatic change of thermal and electrical regimes of the cathode. The Joule heating has virtually no effect over characteristics of spots on rod and infinite planar cathodes.
Effects of parameter variations on negative effective constitutive parameters of non-metallic metamaterials
Authors: Li Yang , Bowler Nicola
Published: February 2013

Analytical expressions describing the variability of effective constitutive parameters of non-metallic metamaterials, as a function of the constituent geometric and material parameters and their variations, have been developed from the total differential of Clausius-Mossotti expressions (using Mie dipole polarizabilities) for the effective (bulk) constitutive parameters of the metamaterial. In practice, these expressions are important for estimating the performance of a metamaterial with particular variations in the parameters of its constituents that arise during the fabrication process, and can be used to guard against extinction of desired double negative (DNG) behavior. With the derived expressions, the effects of parameter variations on effective constitutive parameters of non-metallic metamaterials have been analyzed for three types of metamaterials: (i) cubic arrays of identical magnetodielectric spheres; (ii) cubic arrays of dielectric spheres with equal radius but two different permittivities; and (iii) cubic arrays of dielectric spheres with equal permittivity but two different radii. These effects are evaluated in terms of the calculated variations in values of the effective constitutive parameters of the metamaterial in the vicinity of the DNG or single negative (SNG) band for particular geometric and material parameters and their variations. Results show that variation in the following parameters impacts DNG bandwidth. Listed in order from greatest to least influence: (i) sphere radius; (ii) sphere permittivity and permeability; (iii) lattice constant of the array; and (iv) the constitutive parameters of the array medium, all impact the width of the achievable DNG band. For particular cases studied here, results also show that the DNG behavior may be extinguished if there are 0.78%, 0.016%, and 0.016% variations in all parameters of metamaterial types (i), (ii), and (iii), respectively, as defined above. For the design of non-metallic metamaterials with inclusions, having arbitrary material parameters, in either periodic or random arrangement, the presented results can give a qualitative guide on the level of fabrication tolerances that should be achieved in order to observe the predicted SNG or DNG behavior experimentally.
Effect of temperature and concentration on commercial silicon module based low-concentration photovoltaic system
Authors: Yadav Pankaj , Tripathi Brijesh , Lokhande Makarand , Kumar Manoj
Published: February 2013

A low-concentration photovoltaic (LCPV) system has immense potential for further cost reduction of solar photovoltaic (PV) power as compared to flat panel PV. This paper explains the performance of commercially available solar PV module mounted on parabolic trough collector experimentally and theoretically. A piecewise linear parabolic trough collector is modeled and designed to focus the solar radiation with uniform intensity on solar PV module. Silicon solar PV module based LCPV system is also modeled and simulated to study the variation of output power, open-circuit voltage, and short-circuit current with respect to module temperature and irradiance. The developed theoretical model is able to predict the performance of a LCPV system under the actual test conditions (ATCs). It was observed that the open-circuit voltage decreases from 9.86 to 8.24 V with temperature coefficient of voltage ≈−0.021 V/K under ATC. The short-circuit current of LCPV system shows increasing trend with light concentration with a rate of ≈0.285 Am2/kW. The results confirm that the commercially available silicon solar PV module performs satisfactorily up to ∼8 Sun concentration.
Torque ripple minimization and maximum power point tracking of a permanent magnet reluctance generator for wind energy conversion system
Authors: Sunan E. , Kucuk F. , Raza K. S. , Goto H. , Guo H. J. , Ichinokura O.
Published: February 2013

A permanent magnet reluctance generator (PMRG), which is the member of switched reluctance machine (SRM) family, has an extremely simple and robust structure: no winding on both rotor and stator. Required flux for energy conversion is provided by magnets buried in stator yokes. Thus, it seems to be suitable for wind energy conversion systems (WECSs) for reducing power generation cost to the level of fossil energy conversion systems. In a PMRG based conventional WECS, the PMRG is often accompanied by a simple diode bridge and a maximum power point tracking (MPPT) controlled converter. This type of converter topology does not allow utilizing any torque ripple minimization strategy. Thus, the system inevitably suffers from large torque ripples due to the doubly salient structure of both stator and rotor of the PMRG. Torque ripples propagate acoustic noise, vibrations, and mechanical stress in the turbine-shaft. Exposing to such ripples may result serious failure or damage in the WECS. In this paper, a novel algorithm consisting of MPPT and torque ripple control has been tested on the PMRG based WECS. The control strategy is applied to the system through an asymmetric half bridge (AHB) converter which is accepted to be a traditional converter for SRMs. The performance of control method has been verified under the conditions of constant and variable wind speed. Both simulation and experiment results prove that the control algorithm with the AHB converter allows significant torque ripple reduction in PMRG based WECS while generating power at its maximum point.
Stretching DNA by electric field and flow field in microfluidic devices: An experimental validation to the devices designed with computer simulations
Authors: Lee Cheng-Han , Hsieh Chih-Chen
Published: February 2013

We examined the performance of three microfluidic devices for stretching DNA. The first device is a microchannel with a contraction, and the remaining two are the modifications to the first. The modified designs were made with the help of computer simulations [C. C. Hsieh and T. H. Lin, Biomicrofluidics 5(4), 044106 (2011) and C. C. Hsieh, T. H. Lin, and C. D. Huang, Biomicrofluidics 6, 044105 (2012)] and they were optimized for operating with electric field. In our experiments, we first used DC electric field to stretch DNA. However, the experimental results were not even in qualitative agreement with our simulations. More detailed investigation revealed that DNA molecules adopt a globular conformation in high DC field and therefore become more difficult to stretch. Owing to the similarity between flow field and electric field, we turned to use flow field to stretch DNA with the same devices. The evolution patterns of DNA conformation in flow field were found qualitatively the same as our prediction based on electric field. We analyzed the maximum values, the evolution and the distributions of DNA extension at different Deborah number in each device. We found that the shear and the hydrodynamic interaction have significant influence on the performance of the devices.
Characterizing chaotic dynamics from simulations of large strain behavior of a granular material under biaxial compression
Authors: Small Michael , Walker David M. , Tordesillas Antoinette , Tse Chi K.
Published: February 2013

For a given observed time series, it is still a rather difficult problem to provide a useful and compelling description of the underlying dynamics. The approach we take here, and the general philosophy adopted elsewhere, is to reconstruct the (assumed) attractor from the observed time series. From this attractor, we then use a black-box modelling algorithm to estimate the underlying evolution operator. We assume that what cannot be modeled by this algorithm is best treated as a combination of dynamic and observational noise. As a final step, we apply an ensemble of techniques to quantify the dynamics described in each model and show that certain types of dynamics provide a better match to the original data. Using this approach, we not only build a model but also verify the performance of that model. The methodology is applied to simulations of a granular assembly under compression. In particular, we choose a single time series recording of bulk measurements of the stress ratio in a biaxial compression test of a densely packed granular assembly—observed during the large strain or so-called critical state regime in the presence of a fully developed shear band. We show that the observed behavior may best be modeled by structures capable of exhibiting (hyper-) chaotic dynamics.