bluuebunny/crossref_metadata_2025 huggingface dataset:
Anisotropic charge transport and contact resistance of 6,13-bis(triisopropylsilylethynyl) pentacene field-effect transistors fabricated by a modified flow-coating method
Authors: Sakamoto Kenji , Ueno Junichi , Bulgarevich Kirill , Miki Kazushi
Published: March 2012

Using a modified flow-coating method, bottom-gate/bottom-contact type organic field-effect transistors (OFETs) with a highly oriented active layer of 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-pentacene) were fabricated. The flow-coated TIPS-pentacene films were fairly uniform and consisted of arrays of needle-shaped crystals along the flow-coating direction. The uniformity allowed us to determine the contact resistance by a transfer line method. The usefulness of the modified flow-coating method for fabricating high performance OFETs has been demonstrated, and we found that not only the field-effect mobility but also the contact resistance significantly depends on the channel current direction with respect to the flow-coating direction.
High-Q (>5000) AlN nanobeam photonic crystal cavity embedding GaN quantum dots
Authors: Sergent S. , Arita M. , Kako S. , Iwamoto S. , Arakawa Y.
Published: March 2012

We report on the fabrication and optical characterization of high-quality-factor AlN one-dimensional nanobeam photonic crystal cavities embedding GaN quantum dots and operating in the ultra-violet range. By means of electron-beam lithography, dry etching and photoelectrochemical etching, we implement a high-frequency nanobeam cavity design in an AlN epilayer containing GaN quantum dots. Room-temperature microphotoluminescence characterization of the fabricated nanobeams exhibits resonances with wavelengths as short as 320 nm and quality factors as high as Qexp = 5.0 × 103 at 380 nm. This constitutes a significant improvement over previously reported group-III nitride photonic crystal cavities in terms of operating wavelength.
Soft layer driven switching of microwave-assisted magnetic recording on segmented perpendicular media
Authors: Qiang Goh Jing , Yuan Zhi-Min , Shen Lei , Zhou Tiejun , Ping Feng Yuan
Published: March 2012

In this work, we use micromagnetic modeling to investigate microwave-assisted magnetic recording on segmented perpendicular media. Two types of microwave fields, sinusoidal and finite bandwidth square microwaves, have been chosen for our study. We show that microwave fields, when applied to the soft segment, can assist the magnetization reversal of the hard segment. The calculated assisted frequencies are insensitive to the variation of inter-segment exchange coupling of segmented perpendicular media. Our results suggest that sinusoidal microwave fields are practically more feasible than square microwave fields for the soft layer driven switching mechanism of segmented perpendicular media.
Tensile softening of metallic-glass-matrix composites in the supercooled liquid region
Authors: Qiao J. W. , Zhang Y. , Jia H. L. , Yang H. J. , Liaw P. K. , Xu B. S.
Published: March 2012

A Ti-based metallic-glass-matrix composite exhibits tensile softening (necking) in the supercooled liquid region, accompanied by a large tensile ductility and a fragmentation of dendrites. Subjected to high temperatures, concurrent crystallization does not occur, suggesting a good thermal stability of the glass matrix. The presence of high-volume-fractioned dendrites lowers the rheology of the viscous glass matrix at high temperatures, which results in an absence of super elongation as monolithic bulk metallic glasses (BMGs). A tensile strength of 970 MPa is higher than those of most BMGs under varying strain rates, ascribing to the retardation of softening by the dendrites.
Some observations on the mechanics and dynamics of tumor heterogeneity
Authors: Gillies G. T.
Published: March 2012

The genetic, proteomic and cytostructural complexities of malignant neoplasms have received much attention in cancer research for many years. However, studies of the mechanics of neoplastic phenomena at the meso- and macroscales are also now providing opportunities for understanding some aspects of tumor growth and developing new therapeutic possibilities. We provide a brief overview of some of the recent work in these areas, with emphasis on physical considerations of certain aspects of the mechanics and fluid dynamics of tumor cell invasion and dispersion.
Effects of defoliation on flower development in atemoya custard apple (Annona cherimola Mill.×A. squamosa L.) and implications for flower-development modelling
Authors: Olesen Trevor , Muldoon Steven J.
Published: March 2012

The effects of different levels of carbon limitation on the flower development of custard apple were studied in two defoliation experiments. The duration of flower development was unaffected by moderate carbon limitation, but increased with severe limitation. Both moderate and severe limitation caused a decrease in flower dry weight. Some of the data collected were combined with data from an earlier study to develop a model of the dependency of the duration of flower development on temperature. The model was applied to long-term weather records from Alstonville, northern New South Wales, to illustrate the effects of late 20th century warming on the duration of flower development.
Impaired mitochondrial function in murine oocytes is associated with controlled ovarian hyperstimulationand in vitro maturation
Authors: Ge Hongshan , Tollner Theodore L. , Hu Zhen , Da Mimi , Li Xiaohe , Guan HeQin , Shan Dan , Lu Jieqiang , Huang Changjiang , Dong Qiaoxiang
Published: March 2012

The present study was designed to determine whether controlled ovarian hyperstimulation (COH) and in vitro maturation (IVM), two common clinical procedures in human IVF treatment, have an impact on mitochondrial DNA (mtDNA) copy number and mitochondrial function in oocytes. Matured mouse oocytes recovered following COH, IVM and natural cycles (NC), which simulated those treatments in human clinic IVF treatment. The copies of mtDNA, the activity of mitochondria as determined by inner mitochondrial membrane potential and oocyte adenosine trisphosphate (ATP) content, pattern of mitochondrial distribution, reactive oxygen species (ROS) levels and the integrity of the cytoskeleton were evaluated in oocytes. Significant differences were detected between COH and NC groups in all measures, except the pattern of mitochondrial distribution and ROS levels. There were also significant differences detected between IVM and NC treatment groups in the copies of mitochondrial DNA, the level of ROS and the integrity of the cytoskeleton in oocytes. In conclusion, the results of this investigation indicate that non-physiological COH and IVM treatments inhibit mtDNA replication, alter mitochondrial function and increase the percentage of abnormal cytoskeleton and ROS production. Damage related to the mitochondria may partly explain the low efficiency of IVF and high rate of embryonic loss associated with these clinical procedures.
Characterisation of an in vitro system to study maternal communication with spermatozoa
Authors: Aldarmahi Ahmed , Elliott Sarah , Russell Jean , Klonisch Thomas , Hombach-Klonisch Sabine , Fazeli Alireza
Published: March 2012

In vivo, gamete maturation, fertilisation and early embryonic development take place inside the oviduct. Several studies have indicated that local responses towards gametes and embryos are generated by the maternal reproductive tract. However, no defined in vitro model currently exists to allow detailed and systematic investigation of maternal communications with gametes and embryos. Therefore, we characterised an in vitro model based on the interaction of boar spermatozoa with an immortalised porcine oviduct epithelial cell line to evaluate different factors that may affect this model. The factors tested were sperm viability, source of spermatozoa, cell passage effect and the effect of reproductive and non-reproductive epithelial cells in the interaction with spermatozoa. After 24 h of co-incubation, RNA was extracted and used to synthesise cDNA for quantitative real-time PCR. Alteration in the expression of genes such as adrenomedullin, heat-shock 70-kDa protein 8 and prostaglandin E synthase was considered as the end point of this assay. The results showed that sperm viability and cell passage number had an effect on oviductal gene expression in response to spermatozoa. Oviductal cells showed significant alterations in gene expression when compared with non-reproductive epithelial cells. The simple in vitro system described here has potential application for further studies in our understanding of mechanisms involved in maternal interactions with spermatozoa.
Analysis of the generic discourse features of the English-language medical research article
Authors: Fryer Daniel Lees
Published: March 2012

Genre analysis can be used as a means of understanding the communicative practices of specific discourse communities and may therefore be of particular benefit to students in higher education for whom the interpretation and production of discipline-specific texts is paramount. This study takes global medical research as a case in point and examines the generic discourse features of the experimental medical research article (RA), using a systemic-functional and ‘structural moves analysis’ approach. Based on this novel, combined methodology, a sequence of generic rhetorical moves and steps across a series of medical RAs are described in terms of their function and lexicogrammar. The implications of the study are discussed in relation to previous research and their potential pedagogical and methodological applications.
Semantic categories in the indigenous languages of Brazil
Authors: Hengeveld Kees , Braga Maria Luiza , de Melo Barbosa Elisiene , Silveira Coriolano Jaqueline , Jezuino da Costa Juliana , de Souza Martins Mariana , Leite de Oliveira Diego , Maciel de Oliveira Vinicius , Gomes Pereira Luana , Santana Liliane , Luiz do Carmo Santos Cassiano , dos Ramos Soares Viviane
Published: March 2012

This article investigates which semantic categories, as defined in Functional Discourse Grammar, formally manifest themselves in a sample of native languages of Brazil, and the extent to which the distribution of these manifestations across categories can be described systematically in terms of implicational hierarchies. The areas subjected to investigation are basic interrogative words, basic demonstrative words, and nominalization strategies.
Raised aspirations and attainment? A review of the impact of Aimhigher (2004–2011) on widening participation in higher education in England
Authors: Doyle Michael , Griffin Martyn
Published: March 2012

Aimhigher was discontinued on 31 July 2011. This paper reviews the literature analysing its contribution to widening participation to higher education in the UK. Successes of Aimhigher are considered alongside its challenges; particularly the necessity to situate policy within the diverse
demands of 42 areas covering England. These issues are considered in the context of wider contemporary debates concerning the quality of research into widening participation and instruments used to evaluate policy. Four strands of literature are identified and analysed: Aimhigher's impact
and evaluation, its effectiveness in targeting beneficiaries, the progression and tracking of students and policy.
Contributing knowledge and knowledge workers: the role of Chinese universities in the knowledge economy
Authors: Chen Shuang-Ye
Published: March 2012

As China has appeared only recently as an important knowledge producer with growing global economic significance, little is known internationally about how these processes develop and are managed within China. The rapidly expanding Chinese higher education system is playing an increasingly
important role in China's knowledge economy and therefore in the global knowledge society. This paper reviews historically the changing role of Chinese universities from the planned economy to the knowledge economy, analyses their contribution of knowledge and knowledge workers, and critically
reflects on the mechanisms driving or confining their future contribution to the knowledge economy.
Self‐presentation in exercise: Changes over a 12‐week cardiovascular programme for overweight and obese sedentary females
Authors: Pearson Erin S. , Hall Craig R. , Gammage Kimberley L.
Published: March 2012

Self‐presentational concerns, shown to influence exercise‐related cognitions and behaviours, are evaluated frequently in the absence of exercise or following a single bout of physical activity. The purpose of the present study was to examine longitudinally, the extent to which participating in a structured 12‐week cardiovascular exercise intervention elicited changes in self‐presentational efficacy expectancy (SPEE) and social physique anxiety (SPA). Participants were 80 sedentary women with overweight or obesity (mean body mass index 29.02 kg/m2, SD=4.71) between the ages of 19 and 45 wanting to begin an exercise programme (mean age 33.4 years, SD=7.6). The Self‐Presentational Efficacy Scale (SPES) and the Social Physique Anxiety Scale (SPAS) were completed by each participant prior to commencing the study, and at the 6‐ and 12‐week time points. For those who completed the programme, repeated measures ANOVAs indicated significant increases in SPEE between baseline and week 6 (P<0.001, η2=0.37), and week 6 to 12 (P<0.05, η2=0.10), while SPA decreased significantly between baseline and week 6 (P<0.01, η2=0.16). Bivariate correlation analyses revealed that length of participation in the study was positively related to SPEE and negatively related to SPA. Implications of focusing on these variables within a physical activity intervention are discussed with respect to exercise behaviour, programme development and adherence.
Athletes' precompetitive sleep behaviour and its relationship with subsequent precompetitive mood and performance
Authors: Lastella Michele , Lovell Geoff Peter , Sargent Charli
Published: March 2012

This investigation examined precompetitive sleep behaviour of 103 athletes and how it relates to precompetitive mood and subsequent performance. Results revealed that on the night before competition athletes slept well under the recommended target of eight hours of sleep for healthy adults, with almost 70% of athletes experiencing poorer sleep than usual. It was found that anxiety, noise, the need to use the bathroom and early event times were amongst the most commonly reported causes of disrupted sleep in athletes on the night prior to competition. The negative moods of fatigue and tension were both significantly negatively correlated with precompetitive relative sleep quality (r = −0.28, P = 0.004, r = −0.21, P = 0.030, respectively) and total sleep time (r = −0.23, P = 0.023, r = −0.20, P = 0.044, respectively). Additionally, tension was positively correlated with number of awakenings (r = −0.20, P = 0.045). Vigour was seen to be significantly positively associated with relative sleep quality (r = 0.24, P=0.013). The relationships between relative sleep quality and fatigue, tension and vigour accounted for approximately 4 − 5% of the variance in mood scores. Disrupted sleep did not demonstrate any significant relationship with relative sporting performance. Conclusions from the present investigation are that athletes may be at particular risk of disrupted sleep on the night prior to competition, and this disruption can negatively relate to an athlete's precompetitive mood states.
An Exploration of Racial Differences in Deviant Sexual Interests Among Male Adolescent Sexual Offenders
Authors: Burton David L. , Ginsberg Davida
Published: March 2012

In many research studies and findings from federal statistics, oneof the few areas wherein African Americans are less overre-presented in incarcerated settings is for male juvenile sexualassault. In this study, using a large sample the authors hypothe-sized that perhaps this was due to less deviant sexual interestamong these youth (as reported in prior studies) after controllingfor relevant variables that might explain differences in deviantarousal between Caucasian and African American youth. Theresult supported this hypothesis. The authors offered discussion,implications, and suggested individually and culturally basedtreatment for male adolescent sexual offenders.
Socio-Demographic Variables Predicting Formal vs. Informal Juvenile Justice System Handling and Associated Outcomes
Authors: Phillippi Stephen
Published: March 2012

This analysis compares and contrasts first-time juvenile offenders enrolled in a community-based balanced and restorative justice program whose cases were processed either informally or formally. The study examines contributors to both levels of processing and re-offending. This study examines how family characteristics are associated specifically with level of processing, which are unique attributes compared with juvenile justice studies in the literature. Multivariate predictors of formal levels of processing were age, gender, race, type of offense, marital status of biological parents, and the number of children in the home. Analyses also found that almost twice as many youth who were formally processed were recidivists at 1 year as compared to youth who were informally processed. No significant difference was found in regards to rates of recidivism at 3 years.
The Role of Perceptions in Collaborative Relationships: Implications for Forensic Social Work Practice
Authors: Cole Portia L.
Published: March 2012

This study aims to explore the perceptions held by law students who work collaboratively with social work students. Findings from the focus group data indicate that law students’ perceptions of social work may be influenced by stereotypes. Implications for students preparing to enter into forensic social work practice are considered.
Letter from the Editors (3)
Authors: Vaughan-Eden Viola , Butters Rob
Published: March 2012

Letters from the Editors
Directing a chaperone
Authors: Short Ben
Published: March 2012

Study suggests that cranial mesenchyme cells must limit Hsp90 secretion during development.
Sue Biggins: How kinetochores keep control of mitosis
Authors: Sedwick Caitlin
Published: March 2012

Biggins studies kinetochores and the mitotic checkpoint.
Recognition of DNA damage by XPC coincides with disruption of the XPC–RAD23 complex
Authors: Bergink Steven , Toussaint Wendy , Luijsterburg Martijn S. , Dinant Christoffel , Alekseev Sergey , Hoeijmakers Jan H.J. , Dantuma Nico P. , Houtsmuller Adriaan B. , Vermeulen Wim
Published: March 2012

The recognition of helix-distorting deoxyribonucleic acid (DNA) lesions by the global genome nucleotide excision repair subpathway is performed by the XPC–RAD23–CEN2 complex. Although it has been established that Rad23 homologs are essential to protect XPC from proteasomal degradation, it is unclear whether RAD23 proteins have a direct role in the recognition of DNA damage. In this paper, we show that the association of XPC with ultraviolet-induced lesions was impaired in the absence of RAD23 proteins. Furthermore, we show that RAD23 proteins rapidly dissociated from XPC upon binding to damaged DNA. Our data suggest that RAD23 proteins facilitate lesion recognition by XPC but do not participate in the downstream DNA repair process.
The RNA-binding protein Staufen1 is increased in DM1 skeletal muscle and promotes alternative pre-mRNA splicing
Authors: Ravel-Chapuis Aymeric , Bélanger Guy , Yadava Ramesh S. , Mahadevan Mani S. , DesGroseillers Luc , Côté Jocelyn , Jasmin Bernard J.
Published: March 2012

In myotonic dystrophy type 1 (DM1), dystrophia myotonica protein kinase messenger ribonucleic acids (RNAs; mRNAs) with expanded CUG repeats (CUGexp) aggregate in the nucleus and become toxic to cells by sequestering and/or misregulating RNA-binding proteins, resulting in aberrant alternative splicing. In this paper, we find that the RNA-binding protein Staufen1 is markedly and specifically increased in skeletal muscle from DM1 mouse models and patients. We show that Staufen1 interacts with mutant CUGexp mRNAs and promotes their nuclear export and translation. This effect is critically dependent on the third double-stranded RNA–binding domain of Staufen1 and shuttling of Staufen1 into the nucleus via its nuclear localization signal. Moreover, we uncover a new role of Staufen1 in splicing regulation. Overexpression of Staufen1 rescues alternative splicing of two key pre-mRNAs known to be aberrantly spliced in DM1, suggesting its increased expression represents an adaptive response to the pathology. Altogether, our results unravel a novel function for Staufen1 in splicing regulation and indicate that it may positively modulate the complex DM1 phenotype, thereby revealing its potential as a therapeutic target.
The evolution of metazoan extracellular matrix
Authors: Hynes Richard O.
Published: March 2012

The modular domain structure of extracellular matrix (ECM) proteins and their genes has allowed extensive exon/domain shuffling during evolution to generate hundreds of ECM proteins. Many of these arose early during metazoan evolution and have been highly conserved ever since. Others have undergone duplication and divergence during evolution, and novel combinations of domains have evolved to generate new ECM proteins, particularly in the vertebrate lineage. The recent sequencing of several genomes has revealed many details of this conservation and evolution of ECM proteins to serve diverse functions in metazoa.
A novel patch assembly domain in Num1 mediates dynein anchoring at the cortex during spindle positioning
Authors: Tang Xianying , Germain Bryan St. , Lee Wei-Lih
Published: March 2012

During mitosis in budding yeast, cortically anchored dynein generates pulling forces on astral microtubules to position the mitotic spindle across the mother–bud neck. The attachment molecule Num1 is required for dynein anchoring at the cell membrane, but how Num1 assembles into stationary cortical patches and interacts with dynein is unknown. We show that an N-terminal Bin/Amphiphysin/Rvs (BAR)–like domain in Num1 mediates the assembly of morphologically distinct patches and its interaction with dynein for spindle translocation into the bud. We name this domain patch assembly domain (PA; residues 1–303), as it was both necessary and sufficient for the formation of functional dynein-anchoring patches when it was attached to a pleckstrin homology domain or a CAAX motif. Distinct point mutations targeting the predicted BAR-like PA domain differentially disrupted patch assembly, dynein anchoring, and mitochondrial attachment functions of Num1. We also show that the PA domain is an elongated dimer and discuss the mechanism by which it drives patch assembly.
Seasonal bias in editorial decisions for a physics journal: you should write when you like, but submit in July
Authors: SCHREIBER Michael
Published: March 2012

A recent discussion on possible seasonal bias in editorial decisions yielded discrepant results for different journals. All studies agreed that further investigations in different fields are necessary. In this article submission and acceptance data are analyzed using a sample that is much larger than the previously investigated datasets. Specifically all the 15,478 submissions to EPL (formerly Europhysics Letters) submitted within the 12 years from 1999 to 2010 are included. While trends in the yearly number of submitted papers can be seen, these are also reflected in the number of accepted and rejected papers. Monthly fluctuations in the rate of acceptance are strong; averaging over several years smoothes these fluctuations and shows a clear maximum in July. Even more conspicuous fluctuations are found for the acceptance time, i.e. the duration of the reviewing process. Averaging over several years shows that this process is longest for manuscripts submitted in January, May and October.
Summary of the International Workshop on Magnetic Fusion Energy (MFE) Roadmapping in the ITER Era; 7–10 September 2011, Princeton, NJ, USA
Authors: Neilson G.H. , Federici G. , Li J. , Maisonnier D. , Wolf R.
Published: March 2012

With the ITER project now well under way, the countries engaged in fusion research are planning, with renewed intensity, the research and major facilities needed to develop the science and technology for harnessing fusion energy. The Workshop on MFE Roadmapping in the ITER Era was organized to provide a timely forum for an international exchange of technical information and strategic perspectives on how best to tackle the remaining challenges leading to a magnetic fusion DEMO, a nuclear fusion device or devices with a level of physics and technology integration necessary to cover the essential elements of a commercial fusion power plant. Presentations addressed issues under four topics: (1) Perspectives on DEMO and the roadmap to DEMO; (2) Technology; (3) Physics-Technology integration and optimization; and (4) Major facilities on the path to DEMO. Participants identified a set of technical issues of high strategic importance, where the development strategy strongly influences the overall roadmap, and where there are divergent understandings in the world community, namely (1) the assumptions used in fusion design codes, (2) the strategy for fusion materials development, (3) the strategy for blanket development, (4) the strategy for plasma exhaust solution development and (5) the requirements and state of readiness for next-step facility options. It was concluded that there is a need to continue and to focus the international discussion concerning the scientific and technical issues that determine the fusion roadmap, and it was suggested that an international activity be organized under appropriate auspices to foster international cooperation on these issues.
Multi-layered folding with voids
Authors: Dodwell T. J. , Hunt G. W. , Peletier M. A. , Budd C. J.
Published: March 2012

In the deformation of layered materials such as geological strata, or stacks of paper, mechanical properties compete with the geometry of layering. Smooth, rounded corners lead to voids between the layers, while close packing of the layers results in geometrically induced curvature singularities. When voids are penalized by external pressure, the system is forced to trade off these competing effects, leading to sometimes striking periodic patterns. In this paper, we construct a simple model of geometrically nonlinear multi-layered structures under axial loading and pressure confinement, with non-interpenetration conditions separating the layers. Energy minimizers are characterized as solutions of a set of fourth-order nonlinear differential equations with contact-force Lagrange multipliers, or equivalently of a fourth-order free-boundary problem. We numerically investigate the solutions of this free-boundary problem and compare them with the periodic solutions observed experimentally.
On the influence of delamination on laminated paperboard creasing and folding
Authors: Beex Lars A. A. , Peerlings Ron H. J.
Published: March 2012

Laminated paperboard is used as a packaging material for a wide range of products. During production of the packaging, the fold lines are first defined in a so-called creasing (or scoring) operation in order to obtain uncracked folds. During creasing as well as folding, cracking of the board is to be avoided. A mechanical model for a single fold line has been proposed in a previous study (Beex & Peerlings 2009
Int. J. Solids Struct.
46
, 4192–4207) to investigate the general mechanics of creasing and folding, as well as which precise mechanisms trigger the breaking of the top layer. In the present study, we employ this modelling to study the influence of delamination on creasing and folding. The results reveal the separate role of the cohesive zone model and the friction model in the description of delamination. They also show how the amount of delamination behaviour should be controlled to obtain the desired high folding stiffness without breaking of the top layer.
Folding in power-law viscous multi-layers
Authors: Schmalholz Stefan M. , Schmid Daniel W.
Published: March 2012

We study high-amplitude folding in layered rocks with two-dimensional numerical simulations. We employ the finite-element method to model shortening of an incompressible multi-layer with power-law viscous rheology. The Lagrangian numerical mesh is deformed and re-meshed to accurately follow the layer interfaces. Three settings are considered: (i) pure shearing of a confined multi-layer, (ii) simple shearing of a multi-layer above a detachment, and (iii) slump folding owing to gravity sliding. In our pure shear simulations, finite-amplitude folds always develop despite confinement and thin weak interlayers. The fold shapes can be significantly irregular, resulting from initial geometrical heterogeneities that are perturbations of the layer interfaces and differences in layer thickness. The bulk normal viscosity of the multi-layer decreases significantly with progressive folding. This structural softening decreases the bulk normal viscosities by a factor of 2–20. For simple shear, the multi-layer does not develop asymmetric fold shapes significantly. Fold axial planes in the multi-layer are mostly curved and not parallel. For slump folding, fold shapes can be significantly asymmetric exhibiting strongly curved fold axial planes and overturned fold limbs. The rheology of the competent layers has a major impact on the fold shapes for gravity-driven multi-layer folding.
Localized and chaotic folding: the role of axial plane structures
Authors: Hobbs Bruce E. , Ord Alison
Published: March 2012

Most natural fold systems are not sinusoidal in profile. A widely held view is that such irregularity derives solely from inherited initial geometrical perturbations. Although, undoubtedly, initial perturbations can contribute to irregularity, we explore a different (but complementary) view in which the irregular geometry results from some material or system softening process. This arises because the buckling response of a layer (or layers) embedded in a weaker matrix is controlled in a sensitive manner by the nature of the reaction forces exerted by the deforming matrix on the layer. In many theoretical treatments of the folding problem, this reaction force is assumed to be a linear function of some measure of the deformation or deformation rate. This paper is concerned with the influence of nonlinear reaction forces such as arise from nonlinear elasticity or viscosity. Localized folds arising from nonlinearity form in a fundamentally different way than the Biot wavelength selection process. As a particular example of nonlinear behaviour, we examine the influence of axial plane structures made up of layers of different mineralogy formed by chemical differentiation processes accompanying the deformation; they are referred to asmetamorphic layering. The alternating mineralogical composition in the metamorphic layers means that the embedding matrix exerts a reaction force on the folded layers that varies not only with the deflection or the velocity of deflection of the layer, but also in a periodic manner along the length of the folded layers. The influence of this spatially periodic reaction force on the development of localized and chaotic folding is explored numerically.
Detailed example of the identification and crystallographic analysis of a pseudo-merohedrally twinned crystal
Authors: Guzei Ilia , Herbst-Irmer Regine , Munyaneza Apollinaire , Darkwa James
Published: March 2012

A detailed description of the procedures utilized in the non-routine X-ray single-crystal structural determination and refinement of a pseudo-merohedrally twinned crystal of an Fe/Ni organometallic complex is presented. It illustrates to the practitioners of crystallography how to properly handle such cases and describes the logic and concrete steps necessary to account for the twinning, pseudo-symmetry and atomic positional disorder.
Form, function and functionality of two dimeric toluene-2,4-diisocyanate polymorphs
Authors: Vella-Zarb Liana , Dinnebier Robert E.
Published: March 2012

2,4-Dioxo-1,3-diazetidine-1,3-bis(methyl-m-phenylene) diisocyanate (dimerized toluene-2,4-diisocyanate, TDI) is one of the most widely used aromatic diisocyanates in the polymer industry, and it crystallizes in at least two polymorphic forms (form A and form B) depending on reaction conditions. The crystal structures of the two forms were determined from high-resolution laboratory X-ray powder diffraction data using simulated annealing and Rietveld refinement. In spite of a marked structural similarity between them, significant discrepancies in the physical properties of the two forms prompted analysis of their partitioned energy terms in an effort to better our understanding of the driving force behind such differences in behaviour.
Stable isotopes and elasmobranchs: tissue types, methods, applications and assumptions
Authors: Hussey N. E. , MacNeil M. A. , Olin J. A. , McMeans B. C. , Kinney M. J. , Chapman D. D. , Fisk A. T.
Published: March 2012

Stable‐isotope analysis (SIA) can act as a powerful ecological tracer with which to examine diet, trophic position and movement, as well as more complex questions pertaining to community dynamics and feeding strategies or behaviour among aquatic organisms. With major advances in the understanding of the methodological approaches and assumptions of SIA through dedicated experimental work in the broader literature coupled with the inherent difficulty of studying typically large, highly mobile marine predators, SIA is increasingly being used to investigate the ecology of elasmobranchs (sharks, skates and rays). Here, the current state of SIA in elasmobranchs is reviewed, focusing on available tissues for analysis, methodological issues relating to the effects of lipid extraction and urea, the experimental dynamics of isotopic incorporation, diet‐tissue discrimination factors, estimating trophic position, diet and mixing models and individual specialization and niche‐width analyses. These areas are discussed in terms of assumptions made when applying SIA to the study of elasmobranch ecology and the requirement that investigators standardize analytical approaches. Recommendations are made for future SIA experimental work that would improve understanding of stable‐isotope dynamics and advance their application in the study of sharks, skates and rays.
Diminished aversive classical conditioning in pathological gamblers
Authors: Brunborg Geir Scott , Johnsen Bjørn Helge , Mentzoni Rune Aune , Myrseth Helga , Molde Helge , Lorvik Ingjerd Meen , Bu Eli Torild Hellandsjø , Pallesen Ståle
Published: March 2012

Aims  Impaired ability to form associations between negative events in gambling and aversive somatic reactions may be a predisposing factor for pathological gambling. The current study investigated whether a group of pathological gamblers and a control group differed in aversive classical conditioning.

Design  A differential aversive classical conditioning paradigm, which consisted of three phases. In the habituation phase, one 850‐Hz tone stimulus and one 1500‐Hz tone stimulus were presented three times each in random order. In the acquisition phase, the two tones were presented 10 times each in random order, and one was always followed by a 100‐dB burst of white noise. In the extinction phase the two tones were presented three times each without the white noise.

Setting  University laboratory testing facilities and out‐patient treatment facilities.

Participants  Twenty pathological gamblers and 20 control participants.

Measurements  Duration of seven cardiac interbeat‐intervals (IBIs) following tone offset, gambling severity, tobacco and alcohol use, anxiety and depression.

Findings  No group differences were found in the habituation and acquisition phases. However, a significant group × stimuli × trials × IBIs interaction effect was found in the extinction phase (P < 0.049). Follow‐up analysis indicated that the pathological gamblers did not show aversive classical conditioning, but that the control group did.

Conclusions  Pathological gamblers have a diminished capacity to form associations between aversive events and stimuli that predict aversive events. Aversion learning is likely to be an ineffective treatment for pathological gamblers.
The association between drinking motives and alcohol‐related consequences – room for biases and measurement issues?
Authors: Gmel Gerhard , Labhart Florian , Fallu Jean‐Sébastien , Kuntsche Emmanuel
Published: March 2012

Aims  To investigate whether the predominant finding of generalized positive associations between self‐rated motives for drinking alcohol and negative consequences of drinking alcohol are influenced by (i) using raw scores of motives that may weight inter‐individual response behaviours too strongly, and (ii) predictor‐criterion contamination by using consequence items where respondents attribute alcohol use as the cause.

Design  Cross‐sectional study within the European School Survey Project on Alcohol and other Drugs (ESPAD).

Setting  School classes.

Participants  Students, aged 13–16 (n = 5633).

Measurements  Raw, rank and mean‐variance standardized scores of the Drinking Motives Questionnaire—Revised (DMQ‐R); four consequences: serious problems with friends, sexual intercourse regretted the next day, physical fights and troubles with the police, each itemized with attribution (‘because of your alcohol use’) and without.

Findings  As found previously in the literature, raw scores for all drinking motives had positive associations with negative consequences of drinking, while transformed (rank or Z) scores showed a more specific pattern: external reinforcing motives (social, conformity) had negative and internal reinforcing motives (enhancement, coping) had non‐significant or positive associations with negative consequences. Attributed consequences showed stronger associations with motives than non‐attributed ones.

Conclusion  Standard scoring of the Drinking Motives Questionnaire (Revised) fails to capture motives in a way that permits specific associations with different negative consequences to be identified, whereas use of rank or Z‐scores does permit this. Use of attributed consequences overestimates the association with drinking motives.
Comparison of sparse‐grid geometric and random sampling methods in nonlinear inverse solution uncertainty estimation
Authors: Tompkins Michael J. , Fernández Martínez Juan Luis , Fernández Muñiz Zulima
Published: March 2012

A new uncertainty estimation method, which we recently introduced in the literature, allows for the comprehensive search of model posterior space while maintaining a high degree of computational efficiency. The method starts with an optimal solution to an inverse problem, performs a parameter reduction step and then searches the resulting feasible model space using prior parameter bounds and sparse‐grid polynomial interpolation methods. After misfit rejection, the resulting model ensemble represents the equivalent model space and can be used to estimate inverse solution uncertainty. While parameter reduction introduces a posterior bias, it also allows for scaling this method to higher dimensional problems. The use of Smolyak sparse‐grid interpolation also dramatically increases sampling efficiency for large stochastic dimensions. Unlike Bayesian inference, which treats the posterior sampling problem as a random process, this geometric sampling method exploits the structure and smoothness in posterior distributions by solving a polynomial interpolation problem and then resampling from the resulting interpolant. The two questions we address in this paper are 1) whether our results are generally compatible with established Bayesian inference methods and 2) how does our method compare in terms of posterior sampling efficiency. We accomplish this by comparing our method for two electromagnetic problems from the literature with two commonly used Bayesian sampling schemes: Gibbs’ and Metropolis‐Hastings. While both the sparse‐grid and Bayesian samplers produce compatible results, in both examples, the sparse‐grid approach has a much higher sampling efficiency, requiring an order of magnitude fewer samples, suggesting that sparse‐grid methods can significantly improve the tractability of inference solutions for problems in high dimensions or with more costly forward physics.
The effect of using an alternative irrigant between sodium hypochlorite and chlorhexidine to prevent the formation of para‐chloroaniline within the root canal system
Authors: Mortenson D. , Sadilek M. , Flake N. M. , Paranjpe A. , Heling I. , Johnson J. D. , Cohenca N.
Published: March 2012

Mortenson D, Sadilek M, Flake NM, Paranjpe A, Heling I, Johnson JD, Cohenca N. The effect of using an alternative irrigant between sodium hypochlorite and chlorhexidine to prevent the formation of para‐chloroaniline within the root canal system. International Endodontic Journal, 45, 878–882, 2012.

Aim  To determine if the formation of para‐chloroaniline (PCA) can be avoided by using an alternative irrigant following sodium hypochlorite but before chlorhexidine.

Methodology  Fifty‐five single‐rooted teeth were decoronated, instrumented to size 40, .06 taper whilst being irrigated with 14% ethylene‐diamine‐tetra‐acetic acid (EDTA) and 6% NaOCl. Samples were then randomly divided into three experimental and two control groups. Group 1 was irrigated with saline followed by 2% chlorhexidine gluconate (CHX). Group 2 was irrigated with 50% citric acid (CA) followed by 2% CHX. Group 3 was irrigated with 14% EDTA followed by 2% CHX. The chemical identity and quantification of the PCA in the formed precipitate was determined using gas chromatography/mass spectrometry (GC/MS).

Results  All experimental groups contained PCA. The mean level of PCA for group 1 (sterile saline) was 229 ng mL−1, group 2 (citric acid) 72 ng mL−1 and group 3 (EDTA) 400 ng mL−1, respectively. A significant difference was found between the saline and EDTA groups and the negative control (P < 0.05). Although no statistical significance was found between the negative control and citric acid group, PCA was still present in this experimental group.

Conclusions  Citric acid used as the intermittent irrigant had the least amount of PCA formation in the canal system. Until the threshold required to cause biological damage in humans is determined, the combination of NaOCl and CHX in root canal treatment should be avoided.
Variability of physicochemical properties of an epoxy resin sealer taken from different parts of the same tube
Authors: Baldi J. V. , Bernardes R. A. , Duarte M. A. H. , Ordinola‐Zapata R. , Cavenago B. C. , Moraes J. C. S. , de Moraes I. G.
Published: March 2012

Baldi JV, Bernardes RA, Duarte MAH, Ordinola‐Zapata R, Cavenago BC, Moraes JCS, de Moraes IG. Variability of physicochemical properties of an epoxy resin sealer taken from different parts of the same tube. International Endodontic Journal, 45, 915–920, 2012.

Aim  To analyse several physicochemical properties of AH Plus (Dentsply DeTrey, Konstanz, Germany), including setting time, flow, radiopacity and the degree of conversion (DC); and to correlate the results with the source of the material: from the beginning, middle or end of the tubes in which they were supplied.

Methodology  Three experimental groups were established for each property investigated. Group 1 corresponded to material taken from the beginning of tubes A and B; Group 2 corresponded to material taken from the middle of each tube; and group 3 corresponded to that from the end of each tube. The setting time, flow and radiopacity were studied according to American National Standards Institute/American Dental Association (ANSI/ADA) Specification 57. DC was determined from infrared spectra, which were recorded at 1‐h intervals for the first 6 h; then, at 2‐h intervals for the next 14 h; then, at 24 and 30 h. Data were analysed statistically by analysis of variance (anova), Tukey–Kramer, Kruskal–Wallis and Dunn tests, with a significance level of 5%.

Results  Group 1 had a significantly longer setting time (2303 ± 1058 min) (P < 0.05). Group 3 had the lowest flowability (30.0 ± 0.7 mm) and the highest radiopacity (14.85 ± 1.8 mm Al) (P < 0.05). No differences were found for the DC test (P > 0.05).

Conclusion  The results suggest that segregation occurs between the organic and inorganic components of AH Plus sealer, thereby changing the setting time, flow and radiopacity.
Effectiveness of ProTaper, D‐RaCe, and Mtwo retreatment files with and without supplementary instruments in the removal of root canal filling material
Authors: Marques da Silva B. , Baratto‐Filho F. , Leonardi D. P. , Henrique Borges A. , Volpato L. , Branco Barletta F.
Published: March 2012

Marques da Silva B, Baratto‐Filho F, Leonardi DP, Henrique Borges A, Volpato L, Branco Barletta F. Effectiveness of ProTaper, D‐RaCe, and Mtwo retreatment files with and without supplementary instruments in the removal of root canal filling material. International Endodontic Journal, 45, 927–932, 2012.

Aim  To assess the efficacy of different retreatment rotary files in removing gutta‐percha and endodontic sealer from canals.

Methodology  Ninety straight single‐rooted premolars were prepared up to a size 30 and filled with gutta‐percha and sealer and then randomly assigned to six retreatment groups (n = 15). Groups I, III, and V were retreated using rotary systems ProTaper Universal Retreatment (PTUR), D‐RaCe, and Mtwo Retreatment, respectively. Groups II, IV, and VI were retreated using the additional instruments F4, size 40, .04 taper RaCe, and size 40, .04 taper Mtwo, respectively. The roots were split vertically, and images of the halves were obtained using a high‐resolution scanner and evaluated with AutoCAD software to calculate the percentage of residual material. Data were analyzed with Kruskal–Wallis and Student–Newman–Keuls tests using a 5% significance cutoff (P < 0.05).

Results  There were no statistically significant differences (P > 0.05) between groups when additional instruments were used. The percentage of residual material was lowest in the PTUR group and was statistically significant only when compared to the D‐RaCe system (P = 0.0038).

Conclusions  All root canals had residual filling material after retreatment even when additional instruments were used.
Bark extract of Bathysa cuspidata attenuates extra‐pulmonary acute lung injury induced by paraquat and reduces mortality in rats
Authors: Novaes Rômulo D. , Gonçalves Reggiani V. , Cupertino Marli C. , Marques Daiane C. S. , Rosa Damiana D. , Peluzio Maria do Carmo G. , Neves Clóvis A. , Leite João Paulo V.
Published: March 2012

This study investigated the effect of the bark extract of Bathysa cuspidata on paraquat (PQ)‐induced extra‐pulmonary acute lung injury (ALI) and mortality in rats. ALI was induced with a single dose of PQ (30 mg/kg, i.p.), and animals were treated with B. cuspidata extract (200 and 400 mg/kg). Analyses were conducted of survival, cell migration, lung oedema, malondialdehyde, proteins carbonyls, catalase, superoxide dismutase, histopathology and the stereology of lung tissue. Rats exposed to PQ and treated with 200 and 400 mg of the extract presented lower mortality (20% and 30%), compared with PQ alone group (50%). Furthermore, lung oedema, septal thickening, alveolar collapse, haemorrhage, cell migration, malondialdehyde and proteins carbonyl levels decreased, and catalase and superoxide dismutase activity were maintained. These results show that the bark extract of B. cuspidata reduced PQ‐induced extra‐pulmonary ALI and mortality in rats and suggest that these effects may be associated with the inhibition of oxidative damage.