bluuebunny/crossref_metadata_2025 huggingface dataset:
Microsurgical Principles Related to Excision of Intraneural Ganglion at the Elbow
Authors: Xu Qintong , Chen Zenggan , Dellon A. Lee , Zhang Feng
Published: November 2013

We describe the treatment of a ganglion within the ulnar nerve at the elbow and apply the concept that an intraneural ganglion arises from the joint adjacent to the nerve in which the ganglion is located. Successful treatment of nerve compression and prevention of recurrence of the ganglion require disconnection of the nerve from the joint and deflation, not excision, of the ganglion.
Platelet-Rich Plasma for Zone II Flexor Tendon Repair
Authors: Kollitz K. M. , Parsons E. M. , Weaver M. S. , Huang J. I.
Published: November 2013

Background

Platelet-rich plasma (PRP) has shown promise in the treatment of tendinopathy, including rotator cuff and lateral epicondylitis. Here, we evaluate the effect of PRP on healing in a rabbit zone II flexor tendon model.

Methods

Thirty New Zealand white rabbits underwent transection and repair of the second and fourth flexor digitorum profundus. Half of the rabbits received autologous PRP intra-operatively, while the other half underwent standard four-strand tendon repair. Tendons were examined at 2, 4, and 8 weeks postoperatively. Range of motion and ultimate tensile strength were assessed on the fourth toes, while second toes underwent histologic analysis with hematoxylin and eosin, Masson Trichrome, and Picrosirius Red, for assessment of cell count, collagen content, and collagen maturity.

Results

There were no significant differences in ultimate tensile strength between treatments at 2, 4, or 8 weeks. There was a trend towards lower tensile strength in the PRP group at 2 weeks. There was no statistically significant difference in excursion or range of motion between PRP and control tendons. Cell counts at 4 weeks were statistically significantly reduced in the PRP tendons as compared to controls. No difference in collagen content or maturity was detected.

Conclusions

In contrast to previous studies, PRP did not significantly improve ultimate tensile strength. PRP-treated tendons exhibited trends towards reduced healing, including a significant reduction in cell counts as well as a smaller increase in collagen deposition over time as compared to controls. Further study is needed to determine the precise effect of PRP on intrasynovial flexor tendon repairs.
Nonlinear control of unsteady finite-amplitude perturbations in the Blasius boundary-layer flow
Authors: Cherubini S. , Robinet J.-C. , De Palma P.
Published: November 2013

The present work provides an optimal control strategy, based on the nonlinear Navier–Stokes equations, aimed at hampering the rapid growth of unsteady finite-amplitude perturbations in a Blasius boundary-layer flow. A variational procedure is used to find the blowing and suction control law at the wall providing the maximum damping of the energy of a given perturbation at a given target time, with the final aim of leading the flow back to the laminar state. Two optimally growing finite-amplitude initial perturbations capable of leading very rapidly to transition have been used to initialize the flow. The nonlinear control procedure has been found able to drive such perturbations back to the laminar state, provided that the target time of the minimization and the region in which the blowing and suction is applied have been suitably chosen. On the other hand, an equivalent control procedure based on the linearized Navier–Stokes equations has been found much less effective, being not able to lead the flow to the laminar state when finite-amplitude disturbances are considered. Regions of strong sensitivity to blowing and suction have been also identified for the given initial perturbations: when the control is actuated in such regions, laminarization is also observed for a shorter extent of the actuation region. The nonlinear optimal blowing and suction law consists of alternating wall-normal velocity perturbations, which appear to modify the core flow structures by means of two distinct mechanisms: (i) a wall-normal velocity compensation at small times; (ii) a rotation-counterbalancing effect al larger times. Similar control laws have been observed for different target times, values of the cost parameter, and streamwise extents of the blowing and suction zone, meaning that these two mechanisms are robust features of the optimal control strategy, provided that the nonlinear effects are taken into account.
Suitable regions for date palm cultivation in Iran are predicted to increase substantially under future climate change scenarios
Authors: SHABANI F. , KUMAR L. , TAYLOR S.
Published: November 2013

The objective of the present paper is to use CLIMEX software to project how climate change might impact the future distribution of date palm (Phoenix dactylifera L.) in Iran. Although the outputs of this software are only based on the response of a species to climate, the CLIMEX results were refined in the present study using two non-climatic parameters: (a) the location of soils containing suitable physicochemical properties and (b) the spatial distribution of soil types having suitable soil taxonomy for dates, as unsuitable soil types impose problems in air permeability, hydraulic conductivity and root development. Here, two different Global climate models (GCMs), CSIRO-Mk3.0 (CS) and MIROC-H (MR), were employed with the A2 emission scenario to model the potential date palm distribution under current and future climates in Iran for the years 2030, 2050, 2070 and 2100. The results showed that only c. 0·30 of the area identified as suitable by CLIMEX will actually be suitable for date palm cultivation: the rest of the area comprises soil types that are not favourable for date palm cultivation. Moreover, the refined outputs indicate that the total area suitable for date palm cultivation will increase to 31·3 million ha by 2100, compared with 4·8 million ha for current date palm cultivation. The present results also indicate that only heat stress will have an impact on date palm distribution in Iran by 2100, with the areas currently impacted by cold stress diminishing by 2100.
Olfaction, pheromones and life
Authors: Hoskison E E
Published: November 2013

Background:

From an evolutionary standpoint, olfaction is one of the oldest senses, and one that affects all aspects of life. This review discusses the influence of olfaction and pheromones on life.

Methods:

A literature search was conducted using MEDLINE (1966–2012), Embase (1988–2012), The Cochrane Library (1993–2013) and Ovid (1966–2012).

Results:

Olfaction plays an important role in life, from infancy through to adulthood and declining health in old age. Culture, memories and emotions, which add to life's complexity and overall enjoyment, are also influenced by olfaction.

Conclusion:

Olfaction has a chronological influence on life, affecting all aspects from the cradle to the grave; it plays a role in the quality of life as a key ingredient of human evolution, survival and enjoyment.
Social-ecological factors determine spatial variation in human incidence of tick-borne ehrlichiosis
Authors: BAYLES B. R. , ALLAN B. F.
Published: November 2013

The spatial distribution of human cases of tick-borne diseases is probably determined by a combination of biological and socioeconomic factors. A zoonotic tick-borne pathogen, Ehrlichia chaffeensis, is increasing in human incidence in the USA. In this study, the spatial patterns of probable and confirmed E. chaffeensis-associated cases of ehrlichiosis from 2000 to 2011 were investigated at the zip-code level in Missouri. We applied spatial statistics, including global and local regression models, to investigate the biological and socioeconomic factors associated with human incidence. Our analysis confirms that the distribution of ehrlichiosis in Missouri is non-random, with numerous clusters of high incidence. Furthermore, we identified significant, but spatially variable, associations between incidence and both biological and socioeconomic factors, including a positive association with reservoir host density and a negative association with human population density. Improved understanding of local variation in these spatial factors may facilitate targeted interventions by public health authorities.
Katabatic winds and polynya dynamics at Coats Land, Antarctica
Authors: Ebner Lars , Heinemann Günther , Haid Verena , Timmermann Ralph
Published: November 2013

Mesoscale model simulations were conducted for the Weddell Sea region for the autumn and winter periods of 2008 using a high-resolution, limited-area, non-hydrostatic atmospheric model. A sea ice–ocean model was run with enhanced horizontal resolution and high-resolution forcing data of the atmospheric model. Daily passive thermal and microwave satellite data was used to derive the polynya area in the Weddell Sea region. The focus of the study is on the formation of polynyas in the coastal region of Coats Land, which is strongly affected by katabatic flows. The polynya areas deduced from two independent remote sensing methods and data sources show good agreement, while the results of the sea ice simulation show some weaknesses. Linkages between the pressure gradient force composed of a katabatic and a synoptic component, offshore wind regimes and polynya area are identified. It is shown that the downslope surface offshore wind component of Coats Land is the main forcing factor for polynya dynamics, which is mainly steered by the offshore pressure gradient force, where the katabatic force is the dominant term. We find that the synoptic pressure gradient is opposed to the katabatic force during major katabatic wind events.
Is the Antarctic oscillation trend during the recent decades unusual?
Authors: Zhang Ziyin , Gong Daoyi , Kim Seongjoong , Mao Rui , Yang Jing
Published: November 2013

The Antarctic oscillation (AAO) has been characterized by a persistently positive trend in summer (December–January–February, DJF) during the last 50 years. Thus, the question has arisen of whether the trend is unusual. By investigating five reconstructed historical AAO time series for the past 500 years, recurrences of similar and even stronger trends have been found, indicating that the recent DJF AAO trend is not unprecedented in a historical perspective. To estimate the possible roles played by greenhouse gases or/and ozone, an analysis for DJF AAO trends during the 1969–98 period was conducted using three multiple model ensembles derived from the projects of ‘The twentieth-century climate in coupled models’ (20C3M) and ‘Pre-industrial control experiment models’ (PICTL) of the fourth assessment report of the Intergovernmental Panel on Climate Change (IPCC AR4). The results show that the ozone depletion over Antarctica and global warming may play significant roles in the strengthening trend. Combining the simulations and reconstructions we emphasize that the AAO trend related to global warming may get much stronger when enhanced by low-frequency natural variability.
Rapid decline of the largest remaining population of Bengal Florican Houbaropsis bengalensis and recommendations for its conservation
Authors: PACKMAN C. E. , SHOWLER D. A. , COLLAR N. J. , VIRAK SON , MAHOOD S. P. , HANDSCHUH M. , EVANS T. D. , CHAMNAN HONG , DOLMAN P. M.
Published: November 2013

A census of the Critically Endangered Bengal Florican Houbaropsis bengalensis was conducted between March and May 2012 on and surrounding the Tonle Sap floodplain in Cambodia, which supports the last extant population of the Indochinese subspecies blandini. We found a decline in the number of displaying males of 44–64% since a comparable estimate from the same sites in 2005 to 2007. The estimated population, including five individuals at one previously unsurveyed site, is now 216 (95% CI 156–275) displaying males, plus potential non-displaying males and an unknown number of females. If numbers continue to be lost at a similar rate, it is possible that blandini would become extinct within 10 years. Although the population faces multiple threats, this critical situation has primarily been caused by the recent, rapid conversion of the florican’s grassland habitat to intensive, industrial-scale, irrigated rice cultivation. To protect the Bengal Florican from extinction in South East Asia, existing Bengal Florican Conservation Areas (BFCAs) need expansion and improvements, including strengthened legal status by prime ministerial sub-decree and better demarcation, patrolling and management. As priorities, both irrigated rice and scrub encroachment within the BFCAs needs to be reversed, local communities better supported, and land outside the BFCAs monitored and strategically managed for florican conservation. Where possible, further BFCAs need to be established. Land purchase may also be an effective conservation measure; leasing land earmarked for cultivation would be cheaper, but less secure.
Texture Analyses Show Synergetic Effects of Biomechanical and Biochemical Stimulation on Mesenchymal Stem Cell Differentiation into Early Phase Osteoblasts
Authors: Park So Hee , Shin Ji Won , Kang Yun Gyeong , Hyun Jin-Sook , Oh Min Jae , Shin Jung-Woog
Published: November 2013

We investigated the structural complexity and texture of the cytoskeleton and nucleus in human mesenchymal stem cells during early phase differentiation into osteoblasts according to the differentiation–induction method: mechanical and/or chemical stimuli. For this, fractal dimension and a number of parameters utilizing the gray-level co-occurrence matrix (GLCM) were calculated based on single-cell images after confirmation of differentiation by immunofluorescence staining. The F-actin and nuclear fractal dimensions were greater in both stimulus groups compared with the control group. The GLCM values for energy and homogeneity were lower in fibers of the F-actin cytoskeleton, indicating a dispersed F-actin arrangement during differentiation. In the nuclei of both stimulus groups, higher values for energy and homogeneity were calculated, indicating that the chromatin arrangement was chaotic during the early phase of differentiation. It was shown and confirmed that combined stimulation with mechanical and chemical factors accelerated differentiation, even in the early phase. Fractal dimension analysis and GLCM methods have the potential to provide a framework for further investigation of stem cell differentiation.
A yield-only model for the term structure of interest rates
Authors: Şahin Şule , Cairns Andrew J.G. , Kleinow Torsten , Wilkie A. David
Published: November 2013

This paper develops a term structure model for the UK nominal, real and implied inflation spot zero-coupon rates simultaneously. We start with fitting a descriptive yield curve model proposed by Cairns (1998) to fill the missing values for certain given days at certain maturities in the yield curve data provided by the Bank of England. We compare four different fixed ‘exponential rate’ parameter sets and decide the set of parameters which fits the data best. With the chosen set of parameters we fit the Cairns model to the daily values of the term structures. By applying principal component analysis on the hybrid data (Bank of England data and fitted spot rates for the missing values) we find three principal components, which can be described as ‘level’, ‘slope’ and ‘curvature’, for each of these series. We explore the relation between these principal components to construct a ‘yield-only’ model for actuarial applications. Main contribution of this paper is that the models developed in the paper enable the practitioners to forecast three term structures simultaneously and it also provides the forecast for whole term structures rather than just short and long end of the yield curves.
Li-rich Thin Film Cathode Prepared by Pulsed Laser Deposition
Authors: Yan Binggong , Liu Jichang , Song Bohang , Xiao Pengfei , Lu Li
Published: November 2013

Li-rich layer-structured cathode thin films are prepared by pulsed laser deposition. X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), X-ray photoelectron spectroscopy (XPS) and electrochemical testing in half battery cells are used to characterize crystal structure, surface morphology, chemical valence states and electrochemical performance of these thin films, respectively. It is observed that partial layer to spinel transformation takes place during post annealing and the layered structure further gradually transforms to spinel during electrochemical cycling based on the analysis of dQ/dV. Electrochemical measurement shows that the thin film electrode deposited at 350 mTorr and post-annealed at 800°C possesses the best performance.
A molecularly imprinted colloidal array as a colorimetric sensor for label-free detection of p-nitrophenol
Authors: Xue Fei , Meng Zihui , Wang Yifei , Huang Shuyue , Wang Qiuhong , Lu Wei , Xue Min
Published: November 2013

We report on the synthesis of a label-free p-nitrophenol (PNP) responsive crystalline colloidal array (CCA) based on the combination of a photonic crystal and the molecular imprinting technique.
Tunable colors and white-light emission based on a microporous luminescent Zn(ii)-MOF
Authors: He Hongming , Sun Fuxing , Borjigin Tsolmon , Zhao Nian , Zhu Guangshan
Published: November 2013

A microporous MOF material (JUC-113) was synthesized, which has permanent porosity and emits blue light. According to three-primary color, the luminescent properties of JUC-113 can be easily tuned by different combinations of the encapsulation amount of Tb3+ and Eu3+ and generated white-light emission materials.
Exploring a structural protein–drug interactome for new therapeutics in lung cancer
Authors: Peng Xiaodong , Wang Fang , Li Liwei , Bum-Erdene Khuchtumur , Xu David , Wang Bo , Sinn Anthony A. , Pollok Karen E. , Sandusky George E. , Li Lang , Turchi John J. , Jalal Shadia I. , Meroueh Samy O.
Published: November 2013

The pharmacology of drugs is often defined by more than one protein target.
Efficient residual coding algorithm based on Hadamard transform in lossless H.264/AVC
Authors: Wei Shih‐Tse , Kuo Pin‐Chen , Liu Bin‐Da , Yang Jar‐Ferr
Published: November 2013

An efficient lossless coding algorithm for encoding residual data based on H.264/AVC that uses the Hadamard transform to take advantage of data compaction is proposed. To reduce redundancies, the transformed coefficients are compacted using a compact truncation. The compacted coefficients are then compressed by an improved context‐based adaptive variable length coding coder. Simulation results show that the proposed lossless residual coding algorithm reduces the bit rate by >7.5% compared with those obtained using existing H.264/AVC lossless coding systems.
Traduction et adaptation culturelle en français d’un indicateur
de qualité de vie liée aux dysmorphoses orthodontiques : le PIDAQ
Authors: Ngom Papa Ibrahima , Attebi Pascaline , Diouf Joseph Samba , Diop Ba Khady , Badiane Alpha , Diagne Falou
Published: November 2013

Le PIDAQ (Psychosocial Impact of Dental Aesthetics Questionnaire) est un
instrument qui a été mis au point pour évaluer l’impact des dysmorphoses orthodontiques
sur la qualité de vie. L’objectif de cette étude était d’adapter en langue française le
questionnaire PIDAQ. Secondairement, une évaluation de ses propriétés psychométriques et
de sa validité a été mise en œuvre. Les recommandations de Guillemin, et
al. (1993) ont servi de base dans cette perspective. En particulier, les quatre
étapes suivantes sont rigoureusement suivies : étape préparatoire, réunion d’expert,
rétro-traduction et harmonisation. La version en français obtenue à la fin du processus
d’adaptation, que nous avons convenu de nommer QIPEO, est testée sur un échantillon de 42
sujets (33 femmes et 9 hommes) âgés de 24,60 ± 8,66 ans. Les résultats montrent une
excellente fiabilité du PIDAQ avec une cohérence interne des items qui constituent chacun
des domaines variant de 0,67 pour les « préoccupations esthétiques » à 0,87 pour l’« impact
social ». La reproductibilité des réponses données par 14 patients à deux évaluations
différentes séparées de 15 jours est bonne pour les quatre domaines avec un coefficient
intra-classe allant de 0,72 pour l’« impact social » à 0,90 pour la « perception esthétique ».
Cette étude révèle aussi que le PIDAQ a un certain degré de validité pour cette
population, les scores étant, d’une part, associés de façon significative à la perception
qu’ont les patients de l’alignement de leurs dents et, d’autre part, avec la composante de
santé dentaire de l’IOTN (Index of Orthodontic Treatment Need). Une étude
de validation sur un échantillon plus grand et plus variée de sujets issus d’une
population française est recommandée ainsi qu’une analyse de sa réactivité aux changements
(traitement, récidives, etc.).
Entretien avec Birte Melsen
Authors: Melsen Birte , Renger Stéphane
Published: November 2013

Dr Birte Melsen est née à Aabenraa, au Danemark, le 9 Juin 1939.

Elle fait ses études
dentaires au Royal Dental College à Aarhus, Danemark (1964).

Elle est
professeur et chef du Département d’Orthodontie à l’Université dentaire, à Aarhus, depuis
1975 et traite exclusivement des adultes en pratique privée à Lübeck, en Allemagne (temps
partiel depuis 1986).

Birte Melsen est l’auteur de plus de 350 articles et publications,
dans des domaines aussi variés que la croissance et le développement cranio-facial
(recherches sur cadavres humains), la biologie osseuse et les réactions tissulaires, la
distraction osseuse, les implants dentaires, les traitements adultes, les asymétries, la
stabilité à long terme, sans oublier les mini-vis orthodontiques d’ancrage temporaire, les
attaches auto-ligaturantes et l’imagerie.
Reference Correlation of the Thermal Conductivity of Methanol from the Triple Point to 660 K and up to 245 MPa
Authors: Sykioti E. A. , Assael M. J. , Huber M. L. , Perkins R. A.
Published: November 2013

This paper contains new, representative reference equations for the thermal conductivity of methanol. The equations are based in part upon a body of experimental data that has been critically assessed for internal consistency and for agreement with theory whenever possible. In the case of the dilute-gas thermal conductivity, a theoretically based correlation was adopted in order to extend the temperature range of the experimental data. Moreover, in the critical region, the experimentally observed enhancement of the thermal conductivity is well represented by theoretically based equations containing just one adjustable parameter. The correlation is applicable for the temperature range from the triple point to 660 K and pressures up to 245 MPa. The overall uncertainty (at the 95% confidence level) of the correlation over its range of applicability for the liquid and supercritical phases, excluding the critical region, is estimated to be less than 4.4%. The dilute gas region has an estimated uncertainty of 3%, and the liquid at atmospheric pressure is represented to 2%. Uncertainty in regions where data are unavailable for comparison, such as the dense gas region, may be larger.
Spontaneous polarization and pyroelectric effect in the improper ferroelectrics-ferroelastics Gd2(MoO4)3 and Tb2(MoO4)3 at low temperatures
Authors: Matyjasik S. , Shaldin Yu. V.
Published: November 2013

The experimental variations in the spontaneous polarization ΔPs(T) and pyroelectric coefficient γs(T) for Gd2(MoO4)3 (GMO) and Tb2(MoO4)3 (TMO) at low temperatures reported here differ from those for intrinsic ferroelectrics. A fundamental difference is found in the repolarization behavior of samples of GMO and TMO at fixed temperatures of 300 and 4.2 K. While the single domain formation temperature essentially has no effect on the measurements for TMO, a fundamental difference is observed in the case of GMO: single domain formation in the latter at 4.2 K leads to an order of magnitude increase in ΔPs at T > 85 K and distinct anomalies are observed in γs(T), at one of which the pyroelectric coefficient reaches a record peak of 3 × 10−4 C/(m2·K) at T = 25 K. At T = 200 K the pyroelectric coefficients equal −1.45 and −1.8 in units of 10−6 C/(m2·K). Based on these results and taking published data on the rotational structural transformation in the (001) plane and symmetry considerations into account, we propose a crystal physical model for GMO-type improper ferroelectrics consisting of four mesotetrahedra, each of which is made up of three different types (a, b, c) of MoO4 coordination tetrahedra. The physical significance of the pseudodeviator coefficient Q12*, which initiates the phase transition at T > 433 K from one non-centrally symmetric phase (mm2) into another (4¯2m), is discussed in terms of this model.
Long-range ordered nanodomains of grafted electroactive molecules
Authors: Breitwieser R. , Marsault M. , Repain V. , Lagoute J. , Chacon C. , Girard Y. , Rousset S. , Qin Z. , Battaglini N. , Zrig S. , Lang P.
Published: November 2013

We demonstrate the capability to build zero and one-dimensional electroactive molecular nanostructures ordered over a macroscopic scale and stable under ambient conditions. To realize these arrays, we use the selective grafting of functionalized thiols (juglon and terthiophene based) on a self-organized metallic template. The nanoscale patterning of the molecular conductance is demonstrated and analyzed by scanning tunneling spectroscopy. Finally, the influence of the nanostructuring on electro-chemical properties is measured, paving the way to an all-bottom-up fabrication of nanostructured templates for nanosciences.
A hybrid kinetic Monte Carlo method for simulating silicon films grown by plasma-enhanced chemical vapor deposition
Authors: Tsalikis D. G. , Baig C. , Mavrantzas V. G. , Amanatides E. , Mataras D.
Published: November 2013

We present a powerful kinetic Monte Carlo (KMC) algorithm that allows one to simulate the growth of nanocrystalline silicon by plasma enhanced chemical vapor deposition (PECVD) for film thicknesses as large as several hundreds of monolayers. Our method combines a standard n-fold KMC algorithm with an efficient Markovian random walk scheme accounting for the surface diffusive processes of the species involved in PECVD. These processes are extremely fast compared to chemical reactions, thus in a brute application of the KMC method more than 99% of the computational time is spent in monitoring them. Our method decouples the treatment of these events from the rest of the reactions in a systematic way, thereby dramatically increasing the efficiency of the corresponding KMC algorithm. It is also making use of a very rich kinetic model which includes 5 species (H, SiH3, SiH2, SiH, and Si2H5) that participate in 29 reactions. We have applied the new method in simulations of silicon growth under several conditions (in particular, silane fraction in the gas mixture), including those usually realized in actual PECVD technologies. This has allowed us to directly compare against available experimental data for the growth rate, the mesoscale morphology, and the chemical composition of the deposited film as a function of dilution ratio.
A high-speed vertical optical trap for the mechanical testing of living cells at piconewton forces
Authors: Bodensiek Kai , Li Weixing , Sánchez Paula , Nawaz Schanila , Schaap Iwan A. T.
Published: November 2013

Although atomic force microscopy is often the method of choice to probe the mechanical response of (sub)micrometer sized biomaterials, the lowest force that can be reliably controlled is limited to ≈0.1 nN. For soft biological samples, like cells, such forces can already lead to a strain large enough to enter the non-elastic deformation regime. To be able to investigate the response of single cells at lower forces we developed a vertical optical trap. The force can be controlled down to single piconewtons and most of the advantages of atomic force microscopy are maintained, such as the symmetrical application of forces at a wide range of loading rates. Typical consequences of moving the focus in the vertical direction, like the interferometric effect between the bead and the coverslip and a shift of focus, were quantified and found to have negligible effects on our measurements. With a fast responding force feedback loop we can achieve deformation rates as high as 50 μm/s, which allow the investigation of the elastic and viscous components of very soft samples. The potential of the vertical optical trap is demonstrated by measuring the linearity of the response of single cells at very low forces and a high bandwidth of deformation rates.
Epitaxial growth of graphene on 6H-silicon carbide substrate by simulated annealing method
Authors: Yoon T. L. , Lim T. L. , Min T. K. , Hung S. H. , Jakse N. , Lai S. K.
Published: November 2013

We grew graphene epitaxially on 6H-SiC(0001) substrate by the simulated annealing method. The mechanisms that govern the growth process were investigated by testing two empirical potentials, namely, the widely used Tersoff potential [J. Tersoff, Phys. Rev. B 39, 5566 (1989)] and its more refined version published years later by Erhart and Albe [Phys. Rev. B 71, 035211 (2005)]. Upon contrasting the results obtained by these two potentials, we found that the potential proposed by Erhart and Albe is generally more physical and realistic, since the annealing temperature at which the graphene structure just coming into view at approximately 1200 K is unambiguously predicted and close to the experimentally observed pit formation at 1298 K within which the graphene nucleates. We evaluated the reasonableness of our layers of graphene by calculating carbon-carbon (i) average bond-length, (ii) binding energy, and (iii) pair correlation function. Also, we compared with related experiments the various distance of separation parameters between the overlaid layers of graphene and substrate surface.
Theoretical rotation-vibration spectrum of thioformaldehyde
Authors: Yachmenev Andrey , Polyak Iakov , Thiel Walter
Published: November 2013

We present a variational calculation of the first comprehensive T = 300 K rovibrational line list for thioformaldehyde, H2CS. It covers 41 809 rovibrational levels for states up to Jmax = 30 with vibrational band origins up to 5000 cm−1 and provides the energies and line intensities for 547 926 transitions from the ground vibrational state to these levels. It is based on our previously reported accurate ab initio potential energy surface and a newly calculated ab initio dipole moment surface. Minor empirical adjustments are made to the ab initio equilibrium geometry to reduce systematic errors in the predicted intra-band rotational energy levels. The rovibrational energy levels and transition intensities are computed variationally by using the methods implemented in the computer program TROVE. Transition wavelengths and intensities are found to be in excellent agreement with the available experimental data. The present calculations correctly reproduce the observed resonance effects, such as intensity borrowing, thus reflecting the high accuracy of the underlying ab initio surfaces. We report a detailed analysis of several vibrational bands, especially those complicated by strong Coriolis coupling, to facilitate future laboratory assignments.
Six-dimensional (1,0) superconformal models and higher gauge theory
Authors: Palmer Sam , Sämann Christian
Published: November 2013

We analyze the gauge structure of a recently proposed superconformal field theory in six dimensions. We find that this structure amounts to a weak Courant-Dorfman algebra, which, in turn, can be interpreted as a strong homotopy Lie algebra. This suggests that the superconformal field theory is closely related to higher gauge theory, describing the parallel transport of extended objects. Indeed we find that, under certain restrictions, the field content and gauge transformations reduce to those of higher gauge theory. We also present a number of interesting examples of admissible gauge structures such as the structure Lie 2-algebra of an abelian gerbe, differential crossed modules, the 3-algebras of M2-brane models, and string Lie 2-algebras.
A real-time intercepting beam-profile monitor for a medical cyclotron
Authors: Hendriks C. , Uittenbosch T. , Cameron D. , Kellogg S. , Gray D. , Buckley K. , Schaffer P. , Verzilov V. , Hoehr C.
Published: November 2013

There is a lack of real-time continuous beam-diagnostic tools for medical cyclotrons due to high power deposition during proton irradiation. To overcome this limitation, we have developed a profile monitor that is capable of providing continuous feedback about beam shape and current in real time while it is inserted in the beam path. This enables users to optimize the beam profile and observe fluctuations in the beam over time with periodic insertion of the monitor.
Electronic structural and magnetic properties of Mn5Ge3 clusters
Authors: Yuan H. K. , Chen H. , Kuang A. L. , Tian C. L. , Wang J. Z.
Published: November 2013

Theoretical understanding of the stability, ferromagnetism, and spin polarization of Mn5Ge3 clusters has been performed by using the density functional theory with generalized gradient approximation for exchange and correlation. The magnetic moments and magnetic anisotropy energy (MAE) have been calculated for both bulk and clusters, and the enhanced magnetic moment as well as the enlarged MAE have been identified in clusters. The most attractive achievement is that Mn5Ge3 clusters show a fine half-metallic character with large energy scales. The present results may have important implications for potential applications of small Mn5Ge3 clusters as both emerging spintronics and next-generation data-storage technologies.
Experimental and numerical studies of microwave power redistribution during thermal runaway
Authors: Chandran Mahesh , Bogdan Neculaes V. , Brisco Drew , Katz Sarah , Schoonover Jeffrey , Cretegny Laurent
Published: November 2013

Plasma-assisted heating of Al2O3 is used to study power redistribution during thermal runaway when two samples are simultaneously heated in a microwave cavity. It is observed that thermal runaway in one of the samples completely suppresses the power availability to the other, demonstrating that thermal runaway in one region of the cavity acts as a “sink” for microwave power. Similar effects were observed during localized thermal runaway in a spatially extended single sample. Experimental trends were explored numerically by calculating the temperature evolution T (t) when one of the samples undergoes thermal runaway. Numerical investigation qualitatively captures the essential feature that thermal instability in one sample rapidly decreases the temperature of the second sample in agreement with the experimental observation. Experimental and numerical results as well as practical implications are discussed in the context of microwave processing of materials.
Air-stable electrical conduction in oxidized poly[2-methoxy-5-(2-ethylhexyloxy)-p-phenylene vinylene] thin films
Authors: Hossein-Babaei F. , Shabani P. , Azadinia M.
Published: November 2013

Oxidation-caused electroluminescence and electrical conduction deteriorations in poly[2-methoxy-5-(2-ethylhexyloxy)-p-phenylene vinylene] (MEH-PPV) have prevented the material from being used in applications requiring air exposure. Here, we report air-stable electrical conduction in oxidized MEH-PPV layers produced by room temperature annealing of MEH-PPV thin films in air. Oxidized layers exhibit lower, but stable, conductivities. As the process is irreversible, the final conductivity is retained in vacuum, inert gas, hydrogen, and oxygen. The oxidation rates recorded at different conditions for layers of varied thickness and electrode configuration are described by a surface oxidation model. Potentials of the oxidized MEH-PPV layers in sensor technology are demonstrated.
Nonmetal sublattice population induced defect structure in transition metal aluminum oxynitrides
Authors: Shaha K. P. , Rueβ H. , Rotert S. , to Baben M. , Music D. , Schneider J. M.
Published: November 2013

The influence of oxygen concentration on the structure and mechanical properties of V0.5Al0.5OxN1−x thin films (0 ≤ x ≤ 0.8) was investigated. The unexpected experimental lattice parameter decrease with increasing oxygen concentration can be understood based on ab initio data: the oxygen incorporation induced formation of metal vacancies reduces the equilibrium volume and stabilizes the metastable solid solutions. Charge balancing is identified as the underlying physical mechanism by Bader decomposition analysis. Hence, property predictions for these oxynitrides are only meaningful if the defect structure is described.
Impact of N2 and forming gas plasma exposure on the growth and interfacial characteristics of Al2O3 on AlGaN
Authors: Qin Xiaoye , Dong Hong , Brennan Barry , Azacatl Angelica , Kim Jiyoung , Wallace Robert M.
Published: November 2013

The interface and atomic layer deposition (ALD) of Al2O3 on the annealed, N2 plasma and forming gas (N2:H2) exposed Al0.25Ga0.75N surface was studied using in situ X-ray photoelectron spectroscopy and low energy ion scattering spectroscopy. Exposure of the Al0.25Ga0.75N surface to the plasma treatments is able to remove spurious carbon, and readily facilitate uniform ALD Al2O3 nucleation.
Superconducting cuprate heterostructures for hot electron bolometers
Authors: Wen B. , Yakobov R. , Vitkalov S. A. , Sergeev A.
Published: November 2013

Transport properties of the resistive state of quasi-two dimensional superconducting heterostructures containing ultrathin La2−xSrxCuO4 layers synthesized using molecular beam epitaxy are studied. The electron transport exhibits strong deviation from Ohm's law, δV∼γI3, with a coefficient γ(T) that correlates with the temperature variation of the resistivity dρ/dT. Close to the normal state, analysis of the nonlinear behavior in terms of electron heating yields an electron-phonon thermal conductance per unit area ge−ph≈1 W/K cm2 at T = 20 K, one-two orders of magnitude smaller than in typical superconductors. This makes superconducting LaSrCuO heterostructures to be attractive candidate for the next generation of hot electron bolometers with greatly improved sensitivity.
Thermoelectric and mechanical properties of multi-walled carbon nanotube doped Bi0.4Sb1.6Te3 thermoelectric material
Authors: Ren Fei , Wang Hsin , Menchhofer Paul A. , Kiggans James O.
Published: November 2013

Since many thermoelectrics are brittle in nature with low mechanical strength, improving their mechanical properties is important to fabricate devices such as thermoelectric power generators and coolers. In this work, multiwalled carbon nanotubes (CNTs) were incorporated into polycrystalline Bi0.4Sb1.6Te3 through powder processing, which increased the flexural strength from 32 MPa to 90 MPa. Electrical and thermal conductivities were both reduced in the CNT containing materials, leading to unchanged figure of merit. Dynamic Young's and shear moduli of the composites were lower than the base material, while the Poisson's ratio was not affected by CNT doping.
Electroabsorption under white light illumination to investigate the internal electric field of the organic thin-film solar cells under operation
Authors: Nishimura Takuya , Furuyama Tomotaka , Miyazaki Masaru , Tanaka Senku , Hiromitsu Ichiro
Published: November 2013

Internal electric field of the Schottky-barrier solar cells ITO/pentacene/H2-phthalocyanine (H2Pc)/In/Al (cell A) and ITO/H2Pc/In/Al (cell B) was studied by electroabsorption spectroscopy under white light illumination. The H2Pc films in the two cells have different crystal orientations. Under short-circuit condition, the average internal field in the H2Pc layer of cell A is increased by 2.5 times by an illumination of 40 mW/cm2 white light, which is due to a trapping of photogenerated holes and a resulting dipole layer formation at the H2Pc/In interface, while that of cell B is not affected by the white light illumination.
Wave dispersion in the hybrid-Vlasov model: Verification of Vlasiator
Authors: Kempf Yann , Pokhotelov Dimitry , von Alfthan Sebastian , Vaivads Andris , Palmroth Minna , Koskinen Hannu E. J.
Published: November 2013

Vlasiator is a new hybrid-Vlasov plasma simulation code aimed at simulating the entire magnetosphere of the Earth. The code treats ions (protons) kinetically through Vlasov's equation in the six-dimensional phase space while electrons are a massless charge-neutralizing fluid [M. Palmroth et al., J. Atmos. Sol.-Terr. Phys. 99, 41 (2013); A. Sandroos et al., Parallel Comput. 39, 306 (2013)]. For first global simulations of the magnetosphere, it is critical to verify and validate the model by established methods. Here, as part of the verification of Vlasiator, we characterize the low-β plasma wave modes described by this model and compare with the solution computed by the Waves in Homogeneous, Anisotropic Multicomponent Plasmas (WHAMP) code [K. Rönnmark, Kiruna Geophysical Institute Reports No. 179, 1982], using dispersion curves and surfaces produced with both programs. The match between the two fundamentally different approaches is excellent in the low-frequency, long wavelength range which is of interest in global magnetospheric simulations. The left-hand and right-hand polarized wave modes as well as the Bernstein modes in the Vlasiator simulations agree well with the WHAMP solutions. Vlasiator allows a direct investigation of the importance of the Hall term by including it in or excluding it from Ohm's law in simulations. This is illustrated showing examples of waves obtained using the ideal Ohm's law and Ohm's law including the Hall term. Our analysis emphasizes the role of the Hall term in Ohm's law in obtaining wave modes departing from ideal magnetohydrodynamics in the hybrid-Vlasov model.
Induction of high-affinity NO3– uptake in grapevine roots is an active process correlated to the expression of specific members of the NRT2 and plasma membrane H+-ATPase gene families
Authors: Pii Youry , Alessandrini Massimiliano , Guardini Katia , Zamboni Anita , Varanini Zeno
Published: November 2013

The phenomenon of NO3– induction in plant roots has been characterised both in herbaceous and woody plants. Grapevine (Vitis vinifera L.) plants, hydroponically grown, showed an increase in NO3– uptake rate in response to anion treatment for different periods in the nutrient solution after 1 week of NO3– deprivation. The expression profile of the two high-affinity NO3– transporters VvNRT2.4A and VvNRT2.4B, and the gene encoding the accessory protein VvNAR2.2 exhibits a similar trend to that of the anion uptake. The induction, also involving the increase in activity and protein levels of plasma membrane H+-ATPase, is correlated with the expression profile of two (VvHA2 and VvHA4) out of eight putative plasma membrane H+-ATPase genes identified in grapevine genome.
Application of spatial analysis technology to the planning of access to oral health care for at-risk populations in Australian capital cities
Authors: Almado Haidar , Kruger Estie , Tennant Marc
Published: November 2013

Australians are one of the healthiest populations in the world but there is strong evidence that health inequalities exist. Australia has 23.1 million people spread very unevenly over ~20 million square kilometres. This study aimed to apply spatial analysis tools to measure the spatial distribution of fixed adult public dental clinics in the eight metropolitan capital cities of Australia. All population data for metropolitan areas of the eight capital cities were integrated with socioeconomic data and health-service locations, using Geographic Information Systems, and then analysed. The adult population was divided into three subgroups according to age, consisting of 15-year-olds and over (n = 7.2 million), retirees 65 years and over (n = 1.2 million), and the elderly, who were 85 years and over (n = 0.15 million). It was evident that the States fell into two groups; Tasmania, Northern Territory, Australian Capital Territory and Western Australia in one cluster, and Victoria, New South Wales, Queensland and South Australia in the other. In the first group, the average proportion of the population of low socioeconomic status living in metropolitan areas within 2.5 km of a government dental clinic is 13%, while for the other cluster, it is 42%. The clustering remains true at 5 km from the clinics. The first cluster finds that almost half (46%) of the poorest 30% of the population live within 5 km of a government dental clinic. The other cluster of States finds nearly double that proportion (86%). The results from this study indicated that access distances to government dental services differ substantially in metropolitan areas of the major Australian capital cities.
Death-specific protein in a marine diatom regulates photosynthetic responses to iron and light availability
Authors: Thamatrakoln Kimberlee , Bailleul Benjamin , Brown Christopher M. , Gorbunov Maxim Y. , Kustka Adam B. , Frada Miguel , Joliot Pierre A. , Falkowski Paul G. , Bidle Kay D.
Published: November 2013

Significance

Diatoms are unicellular eukaryotic phytoplankton responsible for nearly one-half of total marine primary productivity. We identified a plastid-targeted protein in the coastal diatom
Thalassiosira pseudonana
(TpDSP1) that enhances growth during iron limitation under low light. Clone lines overexpressing TpDSP1 had lower quantum requirements for growth, increased levels of photosynthetic and carbon fixation proteins, and increased cyclic electron flow around photosystem I, an energy-producing pathway with a heretofore unappreciated role in diatoms. At the same time, clones growing under replete conditions had markedly reduced growth and photosynthetic rates under high light, suggesting that, although TpDSP1 confers a competitive advantage under iron limitation, cells walk an ecological tightrope through the regulation of this protein.
The HIV-1 reservoir in eight patients on long-term suppressive antiretroviral therapy is stable with few genetic changes over time
Authors: Josefsson Lina , von Stockenstrom Susanne , Faria Nuno R. , Sinclair Elizabeth , Bacchetti Peter , Killian Maudi , Epling Lorrie , Tan Alice , Ho Terence , Lemey Philippe , Shao Wei , Hunt Peter W. , Somsouk Ma , Wylie Will , Douek Daniel C. , Loeb Lisa , Custer Jeff , Hoh Rebecca , Poole Lauren , Deeks Steven G. , Hecht Frederick , Palmer Sarah
Published: November 2013

Significance

Identifying the source and dynamics of persistent HIV-1 during combinational antiretroviral therapy (cART) is crucial for understanding the barriers to curing HIV infection. Through genetic characterization of HIV-1 DNA in infected cells from peripheral blood and gut-associated lymphoid tissue from patients after long-term suppressive cART, our study reveals that the primary barrier to a cure is a remarkably stable pool of infected memory CD4
+
T cells. Through in-depth phylogenetic analyses, we determined that the HIV-1 reservoir in these cells from eight patients is kept stable during long-term cART and, with little evidence of viral replication, this population could be maintained by homeostatic cell proliferation or other processes.
Suppression of WC-independent
frequency
transcription by RCO-1 is essential for
Neurospora
circadian clock
Authors: Zhou Zhipeng , Liu Xiao , Hu Qiwen , Zhang Ning , Sun Guangyan , Cha Joonseok , Wang Ying , Liu Yi , He Qun
Published: November 2013

Significance

Rhythmic clock gene transcription is essential for the functions of eukaryotic circadian clocks. In the
Neurospora
circadian oscillator, the WHITE COLLAR (WC) complex is responsible for rhythmic
frequency
(
frq
) transcription and was thought to be the only transcriptional activator for
frq
. Here, we show that
frq
can be constitutively transcribed in a WC-independent manner when the transcriptional corepressor
rco-1
is deleted. In
rco-1
mutants, high-level constitutive WC-independent
frq
transcription results in impaired WC activity and loss of circadian rhythmicity. Our results further indicate that RCO-1 acts together with the histone modifier SET-2 and the chromatin remodeling factor CHD-1 to regulate normal chromatin structure at the
frq
locus, which permits rhythmic
frq
transcription.