bluuebunny/crossref_metadata_2025 huggingface dataset:
Iridium and Rhodium Complexes within a Macroreticular Acidic Resin: A Heterogeneous Photocatalyst for Visible‐light Driven H2 Production without an Electron Mediator
Authors: Mori Kohsuke , Kubota Yoshihiko , Yamashita Hiromi
Published: October 2013

Direct ion exchange of cyclometalated iridium(III) and tris‐2,2′‐bipyridyl rhodium(III) complexes, of which the former acts as a photosensitizer and the latter as a proton reduction catalyst, within a macroreticular acidic resin has been accomplished with the aim of developing a photocatalyst for H2 production under visible‐light irradiation. Ir LIII‐edge and Rh K‐edge X‐ray absorption fine structure (XAFS) measurements suggest that the Ir and Rh complexes are easily accommodated in the macroreticular space without considerable structural changes. The photoluminescence emission of the exchanged Ir complex due to a triplet ligand charge‐transfer (3LC) and metal‐to‐ligand charge‐transfer (3MLCT) transition near 550 nm decreases with increasing the amount of the Rh complex, thus suggesting the occurrence of an electron transfer from Ir to Rh. The Ir‐Rh/resin catalyst behaves as a heterogeneous photocatalyst capable of both visible‐light sensitization and H2 production in an aqueous medium in the absence of an electron mediator. The photocatalytic activitity is strongly dependent on the amount of the components and reaches a maximum at a molar ratio of 2:1 of Ir/Rh complexes. Moreover, leaching and agglomeration of the active metal complexes are not observed, and the recovered photocatalyst can be recycled without loss in catalytic activity.
Sigma‐2 Receptor Agonists as Possible Antitumor Agents in Resistant Tumors: Hints for Collateral Sensitivity
Authors: Niso Mauro , Abate Carmen , Contino Marialessandra , Ferorelli Savina , Azzariti Amalia , Perrone Roberto , Colabufo Nicola Antonio , Berardi Francesco
Published: October 2013

With the aim of contributing to the development of novel antitumor agents, high‐affinity σ2 receptor agonists were developed, with 6,7‐dimethoxy‐2‐[4‐[1‐(4‐fluorophenyl)‐1H‐indol‐3‐yl]butyl]‐1,2,3,4‐tetrahydroisoquinoline (15) and 9‐[4‐(6,7‐dimethoxy‐1,2,3,4‐tetrahydroisoquinolin‐2‐yl)butyl]‐9H‐carbazole (25) showing exceptional selectivity for the σ2 subtype. Most of the compounds displayed notable antiproliferative activity in human MCF7 breast adenocarcinoma cells, with similar activity in the corresponding doxorubicin‐resistant MCF7adr cell line. Surprisingly, a few compounds, including 25, displayed enhanced activity in MCF7adr cells over parent cells, recalling the phenomenon of collateral sensitivity, which is under study for the treatment of drug‐resistant tumors. All of the compounds showed interaction with P‐glycoprotein (P‐gp), and 15 and 25, with the greatest activity, were able to revert P‐gp‐mediated resistance and reestablish the antitumor effect of doxorubicin in MCF7adr cells. We therefore identified a series of σ2 receptor agonists endowed with intriguing antitumor properties; these compounds deserve further investigation for the development of alternate strategies against multidrug‐ resistant cancers.
Target Hopping as a Useful Tool for the Identification of Novel EphA2 Protein–Protein Antagonists
Authors: Tognolini Massimiliano , Incerti Matteo , Pala Daniele , Russo Simonetta , Castelli Riccardo , Hassan‐Mohamed Iftiin , Giorgio Carmine , Lodola Alessio
Published: October 2013

Lithocholic acid (LCA), a physiological ligand for the nuclear receptor FXR and the G‐protein‐coupled receptor TGR5, has been recently described as an antagonist of the EphA2 receptor, a key member of the ephrin signalling system involved in tumour growth. Given the ability of LCA to recognize FXR, TGR5, and EphA2 receptors, we hypothesized that the structural requirements for a small molecule to bind each of these receptors might be similar. We therefore selected a set of commercially available FXR or TGR5 ligands and tested them for their ability to inhibit EphA2 by targeting the EphA2‐ephrin‐A1 interface. Among the selected compounds, the stilbene carboxylic acid GW4064 was identified as an effective antagonist of EphA2, being able to block EphA2 activation in prostate carcinoma cells, in the micromolar range. This finding proposes the “target hopping” approach as a new effective strategy to discover new protein–protein interaction inhibitors.
Potential utility of cell sheets derived from the anterior cruciate ligament and synovium fabricated in temperature‐responsive culture dishes
Authors: Mitani Genya , Sato Masato , Yamato Masayuki , Kokubo Mami , Takagaki Tomonori , Ebihara Goro , Okano Teruo , Mochida Joji
Published: October 2013

Development of tissue‐engineered materials to treat anterior cruciate ligament (ACL) injury has been limited by the lack of phenotypic markers. We investigated the feasibility of inducing ACL regeneration using cell sheet technology based on the expression of tenomodulin (TNMD) as an early phenotypic marker of ligaments. ACL remnants, the synovium surrounding cruciate ligaments (SCL), the synovium surrounding the infrapatellar fat pads (SIF), and subcutaneous fat tissue (SCF) were obtained from patients undergoing ACL reconstruction or total knee arthroplasty. ACL cell sheets and SCL‐derived cell sheets were fabricated successfully A three‐dimensional bioengineered ACL was generated by combining triple‐layered ACL cell sheets with a bioabsorbable mesh composite. Immunohistochemical examination showed that TNMD was expressed in human ACL fibers, triple‐layered ACL cell sheets, ACL remnants, SCL, and SIF, but not in SCF. Real‐time PCR showed that TNMD mRNA was expressed at substantially higher levels in the ACL, SCL, and SIF than in the SCF. These results suggest that TNMD is a specific marker of the human ACL and that ACL sheets have a phenotype similar to that of the ACL. The greater expression of TNMD in the SCL‐ and SIF‐ suggests that the synovium is a potential cell source for ACL regeneration. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 2927–2933, 2014.
CATTLE, DIAMONDS AND INSTITUTIONS: MAIN DRIVERS OF BOTSWANA'S ECONOMIC DEVELOPMENT, 1850 TO PRESENT
Authors: Hillbom Ellen
Published: October 2013

This study investigates the role of political as well as economic institutions, factor endowments and geography as main drivers of change in Botswana's long‐term economic development, from 1850 to the present. The claim that we need to embrace multi‐causal explanations giving equal explanatory value to all mentioned potential drivers is made. Further, in order not to compress history, we should give equal attention to the pre‐colonial, colonial and post‐independence eras. The study leads by example and provides a thorough analysis that enriches our understanding of the country's past and present. Copyright © 2013 John Wiley & Sons, Ltd.
Swallowing pressure and pressure profiles in young healthy adults
Authors: Matsubara Keigo , Kumai Yoshihiko , Samejima Yasuhiro , Yumoto Eiji
Published: October 2013

Objectives/Hypothesis

To measure the swallowing pressure (SP) of normal subjects using a 2.64‐mm‐diameter high‐resolution manometry (HRM) catheter with 36 circumferential sensors.

Study Design

Repeated measures with subjects serving as controls.

Methods

Thirty healthy subjects swallowed water at different temperatures and volumes to examine the maximum SP at the velopharynx, meso‐hypopharynx, upper esophageal sphincter (UES), and cervical esophagus, and the duration of lowered pressure at the UES.

Results

The maximum SP at any location was unaffected by the volume of water, whereas the maximum SP at the UES and cervical esophagus was affected by the temperature. The duration of lowered SP at the UES was significantly prolonged with 10 versus 2 mL of cold water. The pressure curve in males had two peaks (at the velopharynx and UES), whereas that of females had a single peak at the UES.

Conclusions

Our data obtained with 2.64‐mm HRM demonstrated that as the bolus volume is increased, the duration of lowered SP at the UES is prolonged. The higher maximum SP at the velopharynx in males versus females suggests that there may be a gender difference in pressure at the velopharynx that has not been described previously. This implies that it is necessary to take gender differences into consideration when evaluating the etiology of swallowing dysfunction by examining the SP and SP curve. Moreover, the thinner catheter is less invasive and may contribute to obtaining more physiological measurements.

Level of Evidence

4 Laryngoscope, 124:711–717, 2014
Evaluation of the effects of seawater ingress into 316L lined pipes on corrosion performance
Authors: Machuca L. L. , Murray L. , Gubner R. , Bailey S. I.
Published: October 2013

The potential effects of seawater ingress into 316L lined pipes during subsea tie‐in operations on corrosion performance were investigated. Immersion and accelerated corrosion tests were conducted on 316L in different mixtures of treated seawater. In particular, we examined the effect of oxygen and microorganisms in seawater on the performance of the alloy at the different mixtures of treated seawater to assess the risk of localized corrosion in the event of seawater ingress into pipelines. Results showed that oxygen has a negative impact on the biocidal and oxygen scavenging efficiency of the chemical treatments and a detrimental effect on pitting corrosion.
Effect of hydroxyapatite coating fabricated by electrophoretic deposition method on corrosion behavior and nickel release of NiTi shape memory alloy
Authors: Maleki‐Ghaleh H. , Khalil‐Allafi J. , Khalili V. , Shakeri M. S. , Javidi M.
Published: October 2013

Natural hydroxyapatite (HA) was coated on NiTi alloy using electrophoretic deposition method to improve the corrosion resistance and biocompatibility. Coating process was performed at 120 s in various applied voltages of 40, 60, and 80 V. Sintering process was done at 800 °C under inert gas for 2 h. Electrochemical behavior of the coated samples was investigated in simulated body fluid by using electrochemical impedance spectroscopy and polarization tests. Furthermore, the nickel ions release from NiTi and HA coated‐NiTi samples were analyzed by atomic absorption analysis. Ultimately, scanning electron microscopy micrographs and X‐ray diffraction patterns were used to evaluate the morphology and phase analysis of HA coatings. The results show that the sample coated at 60 V reveals a uniform, dense coating accompanied with a higher corrosion resistance. Moreover, after 4 weeks, nickel ions release was reduced to 0.205 µg/cm2 for coated sample at 60 V.
Which factors are associated with trainees' confidence in performing obstetric and gynecological ultrasound examinations?
Authors: Tolsgaard M. G. , Rasmussen M. B. , Tappert C. , Sundler M. , Sorensen J. L. , Ottesen B. , Ringsted C. , Tabor A.
Published: October 2013

Objective

To explore the association between clinical training characteristics and trainees' level of confidence in performing ultrasound scans independently.

Methods

A cross‐sectional e‐survey was distributed to members of the national societies of junior obstetricians/gynecologists in Denmark, Sweden and Norway (n = 973). Multiple linear regression models were used to explore the effect that amount of time spent in specialized ultrasound units and clinical experience had on trainees' confidence in performing ultrasonography independently. Exploratory factor analysis was used to identify factors that contributed to trainees' confidence in performing ultrasonography. Trainees' ultrasound confidence was finally compared with their expected levels of performance.

Results

Of the 682 respondents (response rate 70.1%), 621 met the inclusion criteria. Clinical experience and time spent in specialized ultrasound units were predictors of trainees' confidence in performing ultrasonography independently (P < 0.001). Trainees required more than 24 months of clinical experience and 12–24 days of training in specialized ultrasound units in order to feel confident about performing transvaginal and transabdominal ultrasound scans independently. Three factors were related to ultrasound confidence: technical aspects, image perception and integration of scan into patient care. There were significant differences between trainees' level of confidence and their expected levels of performance (P < 0.001).

Conclusions

Clinical experience and time spent in specialized ultrasound units were predictors of trainees' confidence in performing ultrasonography independently. Discrepancies between trainees' confidence and their expected levels of performance raised concerns about the adequacy of current ultrasound training programs. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd.
New $ \mathcal{N}=1 $ dualities from orientifold transitions Part II: string theory
Authors: García-Etxebarria Iñaki , Heidenreich Ben , Wrase Timm
Published: October 2013

Abstract

We present a string theoretical description, given in terms of branes and orientifolds wrapping vanishing cycles, of the dual pairs of gauge theories analyzed in [1]. Based on the resulting construction we argue that the duality that we observe in field theory is inherited from S-duality of type IIB string theory. We analyze in detail the complex cone over the zeroth del Pezzo surface and discuss an infinite family of orbifolds of flat space. For the del Pezzo case we describe the system in terms of large volume objects, and show that in this language the duality can be understood from the strongly coupled behavior of the O7+ plane, which we analyze using simple F-theory considerations. For all cases we also give a different argument based on the existence of appropriate torsional components of the 3-form flux lattice. Along the way we clarify some aspects of the description of orientifolds in the derived category of coherent sheaves, and in particular we discuss the important role played by exotic orientifolds — ordinary orientifolds composed with auto-equivalences of the category — when describing orientifolds of ordinary quiver gauge theories.
The gradient flow coupling in the Schrödinger functional
Authors: Fritzsch Patrick , Ramos Alberto
Published: October 2013

Abstract

We study the perturbative behavior of the Yang-Mills gradient flow in the Schrödinger Functional, both in the continuum and on the lattice. The energy density of the flow field is used to define a running coupling at a scale given by the size of the finite volume box. From our perturbative computation we estimate the size of cutoff effects of this coupling to leading order in perturbation theory. On a set ofNf= 2 gauge field ensembles in a physical volume ofL~ 0.4 fm we finally demonstrate the suitability of the coupling for a precise continuum limit due to modest cutoff effects and high statistical precision.
Transformations of Spherical Blocks
Authors: Kashani-Poor Amir-Kian , Troost Jan
Published: October 2013

Abstract

We further explore the correspondence between
$ \mathcal{N} $
= 2 supersymmetric SU(2) gauge theory with four flavors on ϵ-deformed backgrounds and conformal field theory, with an emphasis on the ϵ-expansion of the partition function natural from a topological string theory point of view. Solving an appropriate null vector decoupling equation in the semi-classical limit allows us to express the instanton partition function as a series in quasi-modular forms of the group Γ(2), with the expected symmetry W(D
4) ⋊ S
3. In the presence of an elementary surface operator, this symmetry is enhanced to an action of
$ W\left( {D_4^{(1) }} \right)\rtimes {S_4} $
on the instanton partition function, as we demonstrate via the link between the null vector decoupling equation and the quantum Painlevé VI equation.
Hemodynamics of the Reconstructed Gastric Tube During Esophagectomy: Assessment of Outcomes with Indocyanine Green Fluorescence
Authors: Kumagai Youichi , Ishiguro Toru , Haga Norihiro , Kuwabara Koki , Kawano Tatsuyuki , Ishida Hideyuki
Published: October 2013

Background

Construction of a gastric tube that is well perfused with blood during esophagectomy is the most important factor in avoiding anastomotic leakage. We clarified the hemodynamics of the reconstructed gastric tube with indocyanine green (ICG) fluorescence.

Methods

In 20 patients undergoing gastric tube reconstruction during esophagectomy, we evaluated blood flow in the gastric tube with ICG fluorescence imaging. We divided the patients into two groups according to the quality of blood flow to the gastric tube—“good” (n = 9) and “sparse or absent” (n = 11)—based on visual assessment of the anastomosis of the right and left gastroepiploic vessels. We measured the time from initial enhancement of the root of the right gastroepiploic artery until enhancement of the most cranial branch of the left gastroepiploic artery and tip of the gastric tube.

Results

The gastric tube was divisible into three zones according to the dominant arteries present in the greater curvature under ICG fluorescence. The left gastroepiploic artery was enhanced in a direction opposite that of physiological blood flow in all cases. The median period from initial enhancement of the root of the right gastroepiploic artery to the most cranial branch of the left gastroepiploic artery until perfusion up to the tip of the gastric tube did not differ significantly between the “good” and the “sparse or absent” groups (P = 0.24, 0.68)

Conclusions

It is essential to preserve the whole vessel arcade of the greater curvature to achieve good blood perfusion in the gastric tube. The ICG fluorescence method has potential usefulness for evaluation of blood flow in the gastric tube.
Central Role of Relatedness in Alaska Native Youth Resilience: Preliminary Themes from One Site of the Circumpolar Indigenous Pathways to Adulthood (CIPA) Study
Authors: Wexler Lisa , Moses Joshua , Hopper Kim , Joule Linda , Garoutte Joseph
Published: October 2013

This qualitative study of youth resilience takes place in an Alaska Native community, which has undergone rapid, imposed social change over the last three generations. Elders, and successive generations have grown up in strikingly different social, economic and political contexts. Youth narratives of relationships in the context of adolescent growth and development offer insights to better understand culturally‐patterned experience, continuity and change. Local youth and adults shaped the design, implementation and analysis phases of this participatory study. Multiple interviews, totaling 20 older (ages 15–18) and younger (11–14) boys and girls provide accounts of everyday lives and life histories. Although losing close relationships was the most common stressor, many of the participants’ resilience strategies centered on their connections to others. Participants cultivated ‘relatedness’, nurturing relationships that took on kinship qualities. Within these relationships, youth participants acted more responsibly and/or developed a sense of competency and self‐worth because of others’ reliance on them.
Percutaneous Ultrasound-Guided MANOS Carpal Tunnel Release Technique
Authors: Markison Robert E.
Published: October 2013

Ultrasound (US) is used with a minimally invasive cutting device to perform carpal tunnel release with a 3 mm wrist incision. US localizes tendons, arteries, and median nerve for safe introduction of the device into the wrist. The device is inserted in a blunt configuration under the flexor retinaculum, and a cutting wire is deployed that advances a 0.9-mm needle in the palm. The surgeon releases the flexor retinaculum from the inside out through the two skin punctures. Flexor retinaculum release is confirmed with US.
Articles
Authors: Kanamori Osamu
Published: October 2013

Ce texte propose un essai d’interprétation des contes de Kenji Miyazawa à la lumière de la théorie de l’imagination matérielle de Gaston Bachelard. Il s’agit d’une mise à l’épreuve de ce cadre conceptuel dans un contexte culturel totalement différent. Ces contes de fées japonais sont relus en fonction de leurs évocations des quatre éléments d’Empédocle. Ces quatre éléments révèlent une source d’inspiration inconsciente des expressions et des intrigues de cet auteur japonais. Dans son cas, je montrerai que la terre est l’élément dominant.
Bachelard et Brunschvicg. La logique interne du discours scientifique
Authors: Gauthier Yvon
Published: October 2013

Léon Brunschvicg a été un pionnier de la philosophie des mathématiques et de l’épistémologie des sciences exactes en France. Gaston Bachelard peut être considéré comme un des héritiers les plus importants de l’épistémologie constructiviste de Brunschvicg. Les deux philosophes partagent la même conception d’une dialectique immanente de la pensée scientifique et l’idée que la philosophie consiste à construire et à analyser la logique interne du discours scientifique.
Treating symptomatic coronary artery disease in patients with Von Willebrand disease
Authors: A Hassan Syed , Amer Syed , Qureshi Waqas , Alirhayim Zaid , Kuriakose Philip
Published: October 2013

There is limited data on the occurrence of coronary artery disease (CAD) in patients with Von Willebrand disease and the literature is even scarce on their management. We at our institute reviewed the medical records of 198 patients with Von Willebrand disease over a period of 15 years, of which 6 were found to have symptomatic CAD. Acute coronary syndrome was noted in 3 patients while the remaining 3 had stable angina. Cardiac catheterization showed that left main coronary artery was the culprit vessel in all of these patients. In terms of management, stents were placed in 3 patients, two of them underwent coronary artery bypass grafting, and the remaining one patient was medically managed. Aspirin, and in some patients clopidogrel, was well tolerated with minimal side effects.
Climate archives from 90 to 250 ka in horizontal and vertical ice cores from the Allan Hills Blue Ice Area, Antarctica
Authors: Spaulding Nicole E. , Higgins John A. , Kurbatov Andrei V. , Bender Michael L. , Arcone Steven A. , Campbell Seth , Dunbar Nelia W. , Chimiak Laura M. , Introne Douglas S. , Mayewski Paul A.
Published: October 2013

Terrestrial meteorite ages indicate that some ice at the Allan Hills blue ice area (AH BIA) may be as old as 2.2 Ma. As such, ice from the AH BIA could potentially be used to extend the ice core record of paleoclimate beyond 800 ka. We collected samples from 5 to 10 cm depth along a 5 km transect through the main icefield and drilled a 225 m ice core (S27) at the midpoint of the transect to develop the climate archive of the AH BIA. Stable water isotope measurements (δD) of the surface chips and of ice core S27 yield comparable signals, indicating that the climate record has not been significantly altered in the surface ice. Measurements of 40Aratm and δ18Oatm taken from ice core S27 and eight additional shallow ice cores constrain the age of the ice to approximately 90–250 ka. Our findings provide a framework around which future investigations of potentially older ice in the AH BIA could be based.
Spielumwelten im Kindergarten: Auswirkungen auf Geschlechterunterschiede in Spielverhalten und Kompetenzentwicklung
Authors: Mayer Daniela , Bernhard Christina , Peters Annette
Published: October 2013

Die explorative Studie hatte zum Ziel, die Auswirkungen von Spielumwelten im Kindergarten auf Geschlechtertrennung im freien Spiel sowie auf Geschlechterunterschiede im Spielverhalten und der Entwicklung von Mädchen und Jungen in den Bereichen sozial-emotionale Kompetenzen und räumliches Denken zu untersuchen. Die geschlechtstypischen Spielbereiche Bau- und Puppenecke wurden zu einem geschlechtsneutral gestalteten Spielbereich zusammengelegt. Vor und zwei Monate nach der Umgestaltungsmaßnahme wurden in der Kindergartengruppe (14 Mädchen, 10 Jungen) das gleich- und gemischtgeschlechtliche Spiel und das Spielverhalten im Freispiel beobachtet sowie die sozial-emotionalen Kompetenzen und das räumliche Denken der Kinder erfasst. Nach der Umgestaltungsmaßnahme nahm das gemeinsame Spiel von Mädchen und Jungen signifikant zu und im Spielverhalten waren keine Geschlechterunterschiede mehr zu beobachten. Bei den Jungen stieg die Beschäftigung mit Fantasie- und Rollenspielen signifikant an und sie verbesserten sich in ihren sozial-emotionalen Kompetenzen. Die Mädchen spielten signifikant häufiger Konstruktionsspiele und verbesserten sich im räumlichen Denken.
A Tensile Deformation Model for In-situ Dendrite/Metallic Glass Matrix Composites
Authors: Qiao J. W. , Zhang T. , Yang F. Q. , Liaw P. K. , Pauly S. , Xu B. S.
Published: October 2013

In-situ dendrite/metallic glass matrix composites (MGMCs) with a composition of Ti46Zr20V12Cu5Be17 exhibit ultimate tensile strength of 1510 MPa and fracture strain of about 7.6%. A tensile deformation model is established, based on the five-stage classification: (1) elastic-elastic, (2) elastic-plastic, (3) plastic-plastic (yield platform), (4) plastic-plastic (work hardening) and (5) plastic-plastic (softening) stages, analogous to the tensile behavior of common carbon steels. The constitutive relations strongly elucidate the tensile deformation mechanism. In parallel, the simulation results by a finite-element method (FEM) are in good agreement with the experimental findings and theoretical calculations. The present study gives a mathematical model to clarify the work-hardening behavior of dendrites and softening of the amorphous matrix. Furthermore, the model can be employed to simulate the tensile behavior of in-situ dendrite/MGMCs.
Weakly supervised learning of semantic colour terms
Authors: Hanwell David , Mirmehdi Majid
Published: October 2013

Recognition of visual attributes in images allows an image's information content to be expressed textually. This has benefits for web search and image archiving, especially since visual attributes transcend language barriers. Classifiers are traditionally trained using manually segmented images, which are expensive and time consuming to produce. The authors propose a method which uses raw, noisy and unsegmented results of web image searches, to learn semantic colour terms. They use probabilistic graphical models on continuous domain, both for weakly supervised learning, and for segmentation of novel images. Experiments show that the authors methods give better results than the current state of the art in colour naming using noisy, weakly labelled training data.

∗Note: Colour figures are available in the online version of this paper.
Novel multifocus image fusion and reconstruction framework based on compressed sensing
Authors: Yang Zhen‐Zhen , Yang Zhen
Published: October 2013

In this study, an efficient multifocus image fusion and reconstruction framework based on compressed sensing in the wavelet domain are proposed. The new framework is composed of three phases. Firstly, the source images are represented with their sparse coefficients using the discrete wavelet transform (DWT). Secondly, the measurements are obtained by the random Gaussian matrix from their sparse coefficients, and are then fused by the proposed adaptive local energy metrics (ALEM) fusion scheme. Finally, a fast continuous linearised augmented Lagrangian method (FCLALM) is proposed to reconstruct the sparse coefficients from the fused measurement, which will be converted by the inverse DWT (IDWT) to the fused image. Our experimental results show that the proposed ALEM image fusion scheme can achieve a higher fusion quality than some existing fusion schemes. In addition, the proposed FCLALM reconstruction algorithm has a higher peak‐signal‐to‐noise ratio and a faster convergence rate as compared with some existing reconstruction methods.
Molecular field theory for biaxial smectic A liquid crystals
Authors: To T. B. T. , Sluckin T. J. , Luckhurst G. R.
Published: October 2013

Thermotropic biaxial nematic phases seem to be rare, but biaxial smectic A phases less so. Here we use molecular field theory to study a simple two-parameter model, with one parameter promoting a biaxial phase and the second promoting smecticity. The theory combines the biaxial Maier-Saupe and McMillan models. We use alternatively the Sonnet-Virga-Durand (SVD) and geometric mean approximations (GMA) to characterize molecular biaxiality by a single parameter. For non-zero smecticity and biaxiality, the model always predicts a ground state biaxial smectic A phase. For a low degree of smectic order, the phase diagram is very rich, predicting uniaxial and biaxial nematic and smectic phases, with the addition of a variety of tricritical and tetracritical points. For higher degrees of smecticity, the region of stability of the biaxial nematic phase is restricted and eventually disappears, yielding to the biaxial smectic phase. Phase diagrams from the two alternative approximations for molecular biaxiality are similar, except inasmuch that SVD allows for a first-order isotropic-biaxial nematic transition, whereas GMA predicts a Landau point separating isotropic and biaxial nematic phases. We speculate that the rarity of thermotropic biaxial nematic phases is partly a consequence of the presence of stabler analogous smectic phases.
Heterogeneous flow and brittle failure in shock-compressed silicon
Authors: Smith R. F. , Bolme C. A. , Erskine D. J. , Celliers P. M. , Ali S. , Eggert J. H. , Brygoo S. L. , Hammel B. D. , Wang J. , Collins G. W.
Published: October 2013

We combine a recently developed high-resolution two-dimensional (2D) imaging velocimetry technique (velocity interferometer system for any reflector (VISAR)) with 1D VISAR measurements to construct a moving picture of heterogeneous deformation in shock-compressed single crystal silicon. The 2D VISAR takes an intensity snapshot of target velocity and reflectivity over a mm field-of-view while the compression history is simultaneously recorded by the 1D VISAR. Our data show particle velocity surface roughening due to the anisotropic onset of plasticity and, above ∼13 GPa, a structural phase transformation. Shock arrival at the Si free-surface is characterized by the formation of fracture networks and incipient velocity jetting.
The multi-layer multi-configuration time-dependent Hartree method for bosons: Theory, implementation, and applications
Authors: Cao Lushuai , Krönke Sven , Vendrell Oriol , Schmelcher Peter
Published: October 2013

We develop the multi-layer multi-configuration time-dependent Hartree method for bosons (ML-MCTDHB), a variational numerically exact ab initio method for studying the quantum dynamics and stationary properties of general bosonic systems. ML-MCTDHB takes advantage of the permutation symmetry of identical bosons, which allows for investigations of the quantum dynamics from few to many-body systems. Moreover, the multi-layer feature enables ML-MCTDHB to describe mixed bosonic systems consisting of arbitrary many species. Multi-dimensional as well as mixed-dimensional systems can be accurately and efficiently simulated via the multi-layer expansion scheme. We provide a detailed account of the underlying theory and the corresponding implementation. We also demonstrate the superior performance by applying the method to the tunneling dynamics of bosonic ensembles in a one-dimensional double well potential, where a single-species bosonic ensemble of various correlation strengths and a weakly interacting two-species bosonic ensemble are considered.
Efficiency at maximum power of a chemical engine
Authors: Hooyberghs Hans , Cleuren Bart , Salazar Alberto , Indekeu Joseph O. , Van den Broeck Christian
Published: October 2013

A cyclically operating chemical engine is considered that converts chemical energy into mechanical work. The working fluid is a gas of finite-sized spherical particles interacting through elastic hard collisions. For a generic transport law for particle uptake and release, the efficiency at maximum power ηmp takes the form \documentclass[12pt]{minimal}\begin{document}$1/2+c \,\Delta \mu + {\cal O}(\Delta \mu ^2)$\end{document}1/2+cΔμ+O(Δμ2), with 1/2 a universal constant and Δμ the chemical potential difference between the particle reservoirs. The linear coefficient c is zero for engines featuring a so-called left/right symmetry or particle fluxes that are antisymmetric in the applied chemical potential difference. Remarkably, the leading constant in ηmp is non-universal with respect to an exceptional modification of the transport law. For a nonlinear transport model, we obtain ηmp = 1/(θ + 1), with θ > 0 the power of Δμ in the transport equation.
Conduction mechanism of resistance switching in fully transparent MgO-based memory devices
Authors: Zhang Ting , Yin Jiang , Xia Yidong , Zhang Weifeng , Liu Zhiguo
Published: October 2013

Unipolar resistance switching characteristics are observed in fully transparent indium-doped SnO2/MgO/F-doped SnO2 device. In addition to the transmittance above 90% for visible light, the devices show good endurance and retention characteristics. The resistance-temperature relation curves and the corresponding Arrhenius plot confirm the semiconducting conduction behavior of both the high resistance state and the low resistance state. Experimental results indicate that Ohmic and trap controlled space-charge-limited conduction mechanism controlled the charge carriers transport at the low voltage and high voltage regions, respectively. This work presents a candidate material MgO for the application on the future see-through electronic devices.
Instrumentation for laser physics and spectroscopy using 32-bit microcontrollers with an Android tablet interface
Authors: Eyler E. E.
Published: October 2013

Several high-performance lab instruments suitable for manual assembly have been developed using low-pin-count 32-bit microcontrollers that communicate with an Android tablet via a USB interface. A single Android tablet app accommodates multiple interface needs by uploading parameter lists and graphical data from the microcontrollers, which are themselves programmed with easily modified C code. The hardware design of the instruments emphasizes low chip counts and is highly modular, relying on small “daughter boards” for special functions such as USB power management, waveform generation, and phase-sensitive signal detection. In one example, a daughter board provides a complete waveform generator and direct digital synthesizer that fits on a 1.5 in. × 0.8 in. circuit card.
A steady-state non-equilibrium molecular dynamics approach for the study of evaporation processes
Authors: Zhang Jianguo , Müller-Plathe Florian , Yahia-Ouahmed Méziane , Leroy Frédéric
Published: October 2013

Two non-equilibrium methods (called bubble method and splitting method, respectively) have been developed and tested to study the steady state evaporation of a droplet surrounded by its vapor, where the evaporation continuously occurs at the vapor-liquid interface while the droplet size remains constant. In the bubble method, gas molecules are continuously reinserted into a free volume (represented by a bubble) located at the centre of mass of the droplet to keep the droplet size constant. In the splitting method, a molecule close to the centre of mass of the droplet is split into two: In this way, the droplet size is also maintained during the evaporation. By additional local thermostats confined to the area of insertion, the effect of frequent insertions on properties such as density and temperature can be limited to the immediate insertion area. Perturbations are not observed in other parts of the droplet. In the end, both the bubble method and the splitting method achieve steady-state droplet evaporation. Although these methods have been developed using an isolated droplet, we anticipate that they will find a wide range of applications in the study of the evaporation of isolated films and droplets or thin films on heated substrates or under confinement. They can in principle also be used to study the steady-state of other physical processes, such as the diffusion or permeation of gas molecules or ions in a pressure gradient or a concentration gradient.
Tetratic phase of Hertzian spheres: Monte Carlo simulation
Authors: Terao Takamichi
Published: October 2013

The nature of the melting transition of a bilayer comprising Hertzian spheres, confined between parallel walls, was investigated with the multicolour domain decomposition Monte Carlo simulation. It was confirmed that an ordered bilayer structure with a square lattice symmetry appeared parallel to the walls of confinement at a certain density and temperature. Bond-orientational order parameters of the system were studied numerically, and it has been suggested that this system obeys a two-stage melting transition with an intermediate phase called the tetratic phase. A snapshot of the spatial distribution of domains in which the bond-orientational order of the system exists shows a filamentary structure in the transition regime.
Polymerization-induced spinodal decomposition of ethylene glycol/phenolic resin solutions under electric fields
Authors: Zhang Gang , Qiao Guanjun
Published: October 2013

Temporal evolution of polymerization-induced spinodal decomposition (PISD) under electric fields was investigated numerically in ethylene glycol/phenolic resin solutions with different initial composition. A model composed of the nonlinear Cahn-Hilliard-Cook equation for spinodal decomposition and a rate equation for curing reaction was utilized to describe the PISD phenomenon. As initial composition varied, deformed droplet-like and aligned bi-continuous structures were observed in the presence of an electric field. Moreover, the anisotropic parameter (D), determined from the 2D-FFT power spectrum, was employed to quantitatively characterize the degree of morphology anisotropy. The value of D increased quickly in the early stage and then decreased in the intermediate stage of spinodal decomposition, which was attributed to the resistance of coarsening process to morphology deformation and the decline of electric stress caused by polymerization reaction. The results can also provide a guidance on how to control the morphology of monolithic porous polymer and carbon materials with anisotropic structures.
Ultrafast laser induced electronic and structural modifications in bulk fused silica
Authors: Mishchik K. , D'Amico C. , Velpula P. K. , Mauclair C. , Boukenter A. , Ouerdane Y. , Stoian R.
Published: October 2013

Ultrashort laser pulses can modify the inner structure of fused silica, generating refractive index changes varying from soft positive (type I) light guiding forms to negative (type II) values with void presence and anisotropic sub-wavelength modulation. We investigate electronic and structural material changes in the type I to type II transition via coherent and incoherent secondary light emission reflecting free carrier behavior and post-irradiation material relaxation in the index change patterns. Using phase contrast microscopy, photoluminescence, and Raman spectroscopy, we determine in a space-resolved manner defect formation, redistribution and spatial segregation, and glass network reorganization paths in conditions marking the changeover between type I and type II photoinscription regimes. We first show characteristic patterns of second harmonic generation in type I and type II traces, indicating the collective involvement of free carriers and polarization memory. Second, incoherent photoemission from resonantly and non-resonantly excited defect states reveals accumulation of non-bridging oxygen hole centers (NBOHCs) in positive index domains and oxygen deficiency centers (ODCs) with O2− ions segregation in void-like regions and in the nanostructured domains, reflecting the interaction strength. Complementary Raman investigations put into evidence signatures of the different environments where photo-chemical densification (bond rearrangements) and mechanical effects can be indicated. NBOHCs setting in before visible index changes serve as precursors for subsequent compaction build-up, indicating a scenario of cold, defect-assisted densification for the soft type I irradiation regime. Additionally, we observe hydrodynamic effects and severe bond-breaking in type II zones with indications of phase transition. These observations illuminate densification paths in fused silica in low power irradiation regimes, and equally in energetic ranges, characterized by the onset of thermo-mechanical effects.
Fundamental measure density functional theory study of liquid-vapor interface of dipolar and quadrupolar fluids
Authors: Warshavsky V. B. , Zeng X. C.
Published: October 2013

We have studied interfacial structure and properties of liquid-vapor interfaces of dipolar fluids and quadrupolar fluids, respectively, using the classical density functional theory (DFT). Towards this end, we employ the fundamental measure DFT for a reference hard-sphere (HS) part of free energy and the modified mean field approximation for the correlation function of dipolar or quadrupolar fluid. At low temperatures we find that both the liquid-vapor interfacial density profile and orientational order parameter profile exhibit weakly damped oscillatory decay into the bulk liquid. At high temperatures the decay of interfacial density and order parameter profiles is entirely monotonic. The scaled temperature τ = 1 − T/Tc that separates the two qualitatively different interfacial structures is in the range 0.10–0.15. At a given (dimensionless) temperature, increasing the dipolar or quadrupolar moment enhances the density oscillations. Application of an electric field (normal to the interface) will damp the oscillations. Likewise, at the given temperature, increasing the strength of any multipolar moment also increases the surface tensions while increasing the strength of the applied electric field will reduce the surface tensions. The results are compared with those based on the local-density approximations (LDA) for the reference HS part of free energy as well as with results of numerical experiments.
Linear dispersion relation for the mirror instability in context of the gyrokinetic theory
Authors: Porazik Peter , Johnson Jay R.
Published: October 2013

The linear dispersion relation for the mirror instability is discussed in context of the gyrokinetic theory. The objective is to provide a coherent view of different kinetic approaches used to derive the dispersion relation. The method based on gyrocenter phase space transformations is adopted in order to display the origin and ordering of various terms.
A stochastic diffusion process for Lochner's generalized Dirichlet distribution
Authors: Bakosi J. , Ristorcelli J. R.
Published: October 2013

The method of potential solutions of Fokker-Planck equations is used to develop a transport equation for the joint probability of N stochastic variables with Lochner's generalized Dirichlet distribution [R. H. Lochner, “A generalized Dirichlet distribution in Bayesian life testing,” J. R. Stat. Soc. Ser. B (Methodol.) 37(1), 103–113 (1975)] as its asymptotic solution. Individual samples of a discrete ensemble, obtained from the system of stochastic differential equations, equivalent to the Fokker-Planck equation developed here, satisfy a unit-sum constraint at all times and ensure a bounded sample space, similarly to the process developed in [J. Bakosi and J. R. Ristorcelli, “A stochastic diffusion process for the Dirichlet distribution,” Int. J. Stoch. Anal. 2013, 7]. Consequently, the generalized Dirichlet diffusion process may be used to represent realizations of a fluctuating ensemble of N variables subject to a conservation principle. Compared to the Dirichlet distribution and process, the additional parameters of the generlized Dirichlet distribution allow a more general class of physical processes to be modeled with a more general covariance matrix.
The effect of vibrational entropy on the solubility and stability of ordered Al3Li phases in Al-Li alloys
Authors: Mao Zugang , Seidman David N. , Wolverton C.
Published: October 2013

The solubility and stability of three possible ordered Al3Li structures in Al-Li alloys are studied using first-principles calculations: δ′-Al3Li(L12), δ-Al3Li(DO22), and β-Al3Li(DO3). We find that δ′-Al3Li(L12) is the most stable phase and β-Al3Li(DO3) is energetically unfavorable. The vibrational formation entropy makes a significant contribution to the solubility for all three ordered Al3Li structures and yields a 1.6-fold increase in the calculated solubility of δ′-Al3Li(L12), a 1.8-fold increase for δ-Al3Li(DO22), and a 2.5-fold increase for β-Al3Li(DO3). The solubility of δ′-Al3Li(L12) is greater than those of δ-Al3Li(DO22) and β-Al3Li(DO3), and the δ′-Al3Li(L12) solvus curve is in good agreement with the experimental one.
Toughness enhancement in hard ceramic thin films by alloy design
Authors: Kindlund H. , Sangiovanni D. G. , Martínez-de-Olcoz L. , Lu J. , Jensen J. , Birch J. , Petrov I. , Greene J. E. , Chirita V. , Hultman L.
Published: October 2013

Hardness is an essential property for a wide range of applications. However, hardness alone, typically accompanied by brittleness, is not sufficient to prevent failure in ceramic films exposed to high stresses. Using VN as a model system, we demonstrate with experiment and density functional theory (DFT) that refractory VMoN alloys exhibit not only enhanced hardness, but dramatically increased ductility. V0.5Mo0.5N hardness is 25% higher than that of VN. In addition, while nanoindented VN, as well as TiN reference samples, suffer from severe cracking typical of brittle ceramics, V0.5Mo0.5N films do not crack. Instead, they exhibit material pile-up around nanoindents, characteristic of plastic flow in ductile materials. Moreover, the wear resistance of V0.5Mo0.5N is considerably higher than that of VN. DFT results show that tuning the occupancy of d–t2g metallic bonding states in VMoN facilitates dislocation glide, and hence enhances toughness, via the formation of stronger metal/metal bonds along the slip direction and weaker metal/N bonds across the slip plane.
Scanning transmission electron microscopy investigations of self-forming diffusion barrier formation in Cu(Mn) alloys on SiO2
Authors: Lozano J. G. , Bogan J. , Casey P. , McCoy A. P. , Hughes G. , Nellist P. D.
Published: October 2013

Scanning transmission electron microscopy in high angle annular dark field mode has been used to undertake a characterisation study with sub-nanometric spatial resolution of the barrier formation process for a Cu(Mn) alloy (90%/10%) deposited on SiO2. Electron energy loss spectroscopy (EELS) measurements provide clear evidence for the expulsion of the alloying element to the dielectric interface as a function of thermal annealing where it chemically reacts with the SiO2. Analysis of the Mn L23 intensity ratio in the EELS spectra indicates that the chemical composition in the barrier region which has a measured thickness of 2.6 nm is MnSiO3.
Stokes matrices for the quantum cohomologies of a class of orbifold projective lines
Authors: Iwaki Kohei , Takahashi Atsushi
Published: October 2013

We prove the Dubrovin's conjecture for the Stokes matrices for the quantum cohomology of orbifold projective lines. The conjecture states that the Stokes matrix of the first structure connection of the Frobenius manifold constructed from the Gromov-Witten theory coincides with the Euler matrix of a full exceptional collection of the bounded derived category of the coherent sheaves. Our proof is based on the homological mirror symmetry, primitive forms of affine cusp polynomials, and the Picard-Lefschetz theory.
On quantization of nondispersive wave packets
Authors: Altaisky M. V. , Kaputkina N. E.
Published: October 2013

Nondispersive wave packets are widely used in optics and acoustics. We found it interesting that such packets could be also a subject of quantum field theory. Canonical commutation relations for the nondispersive wave packets are constructed.