bluuebunny/crossref_metadata_2025 huggingface dataset:
Collapse of zooplankton stocks during Liriope tetraphylla (Hydromedusa) blooms and dense mucilaginous aggregations in a thermohaline stratified basin
Authors: Yilmaz Izzet Noyan
Published: May 2014

A growing number of studies report an increase in jellyfish populations worldwide that may have consequences for marine planktonic food web dynamics. The principal objective of this study was to understand the changes in a zooplankton community during blooms of Liriope tetraphylla and subsequent mucilage events in the Sea of Marmara, a small highly stratified transitional basin between the Black and Aegean Seas. Liriope blooms observed in 2006 and 2007 reached a maximum abundance of 2978 ind.·m−3, following the species' first observation in 2005. Jellyfish species are known to play a key guild role by restructuring plankton communities and in the Sea of Marmara Liriope caused a temporal regime shift from a crustacean‐ to a jellyfish‐controlled system. A rapid decline in abundance of most important zooplankton species followed the Liriope increase, together with a drastic shift in community structure. The dominant summer–autumn species Penilia avirostris (Cladocera) vanished in the autumn of 2006 and was diminished ~30‐fold in 2007 when compared with years without Liriope. The decline in zooplankton and the devastating effects of mucilage on pelagic ecosystem and socio‐economics through restricting commercial fisheries implied sensitivity of the already perturbed Marmara ecosystem to changes in predator densities and environmental stability.
Impact of Increased Intramuscular Perfusion Heterogeneity on Skeletal Muscle Microvascular Hematocrit in the Metabolic Syndrome
Authors: Butcher Joshua T. , Stanley Shyla C. , Brooks Steven D. , Chantler Paul D. , Wu Fan , Frisbee Jefferson C.
Published: May 2014

Objective

To determine HMV and PS in skeletal muscle of OZR and evaluate the impact of increased microvascular perfusion heterogeneity on mass transport/exchange.

Methods

The in situ gastrocnemius muscle from OZR and LZR was examined under control conditions and following pretreatment with TEMPOL (antioxidant)/SQ‐29548 (PGH2/TxA2 receptor antagonist), phentolamine (adrenergic antagonist), or all agents combined. A spike input of a labeled blood tracer cocktail was injected into the perfusing artery. Tracer washout was analyzed using models for HMV and PS. HT was determined in in situ cremaster muscle of OZR and LZR using videomicroscopy.

Results

HMV was decreased in OZR versus LZR. While TEMPOL/SQ‐29548 or phentolamine had minor effects, treatment with all three agents improved HMV in OZR. HT was not different between strains, although variability was increased in OZR, and normalized following treatment with all three agents. PS was reduced in OZR and was not impacted by intervention.

Conclusions

Increased microvascular perfusion heterogeneity in OZR reduces HMV in muscle vascular networks and increases its variability, potentially contributing to premature muscle fatigue. While targeted interventions can ameliorate this, the reduced microvascular surface area is not acutely reversible.
Recommendations for photo‐identification methods used in capture‐recapture models with cetaceans
Authors: Urian Kim , Gorgone Antoinette , Read Andrew , Balmer Brian , Wells Randall S. , Berggren Per , Durban John , Eguchi Tomoharu , Rayment William , Hammond Philip S.
Published: May 2014

Capture‐recapture methods are frequently employed to estimate abundance of cetaceans using photographic techniques and a variety of statistical models. However, there are many unresolved issues regarding the selection and manipulation of images that can potentially impose bias on resulting estimates. To examine the potential impact of these issues we circulated a test data set of dorsal fin images from bottlenose dolphins to several independent research groups. Photo‐identification methods were generally similar, but the selection, scoring, and matching of images varied greatly amongst groups. Based on these results we make the following recommendations. Researchers should: (1) determine the degree of marking, or level of distinctiveness, and use images of sufficient quality to recognize animals of that level of distinctiveness; (2) ensure that markings are sufficiently distinct to eliminate the potential for “twins” to occur; (3) stratify data sets by distinctiveness and generate a series of abundance estimates to investigate the influence of including animals of varying degrees of markings; and (4) strive to examine and incorporate variability among analysts into capture‐recapture estimation. In this paper we summarize these potential sources of bias and provide recommendations for best practices for using natural markings in a capture‐recapture framework.
When and for how long should glucocorticoids be used in rheumatoid arthritis? International guidelines and recommendations
Authors: Gaujoux‐Viala Cécile , Gossec Laure
Published: May 2014

Glucocorticoids are widely used in rheumatoid arthritis (RA); however, their effectiveness and safety is still a subject of debate. In particular, when to introduce glucocorticoids, but also when and how to taper them, are important questions for clinicians. In this paper, we will discuss the place of glucocorticoids in the European League Against Rheumatism (EULAR) recommendations for the management of RA and review the literature that was the basis for these recommendations. The recommendations cover the introduction of glucocorticoids (and for whom they are recommended), doses and duration of treatment, and tapering strategies. Items still on the research agenda include more data on safety, particularly for long‐term use, and small doses of glucocorticoids.
The role of the folic acid to the prevention of orofacial cleft: an epidemiological study
Authors: Figueiredo RF , Figueiredo N , Feguri A , Bieski I , Mello R , Espinosa M , Damazo AS
Published: May 2014

Background

Orofacial clefts (OFCs) have complex and multifactorial etiologies. Periconceptional folic acid supplementation can significantly reduce the risk ofOFC.

Objective

To evaluate the role of folate and other factors in preventingOFCby analyzing the health and socio‐demographic data collected from a population sample.

Methods

Retrospective case–control study in which mothers with children with or withoutOFCwere evaluated for the following main parameters: nutritional factors, socio‐demographic characteristics, pregnancy and family history, use of folate, and counseling by healthcare professionals.

Results

Socio‐epidemiological analysis of the 80 participants, 40 in the case group and 40 in the control group, found a significant impact on the risk ofOFCrelated to economic and educational status. The mothers who had a diet rich in vegetables and white meat had a lower risk of having children withOFC. A short interval between pregnancies, subsequent pregnancy while still breastfeeding, and family history also increased risk ofOFC.

Conclusions

Limited family planning, diet low in folate, and inadequate use of folate during the periconceptional period and during the first trimester of pregnancy were demonstrated a potential correlation with a high incidence ofOFCin this study.
Long‐term mortality associated with acute kidney injury in children following congenital cardiac surgery
Authors: Watkins Scott C. , Williamson Kelly , Davidson Mario , Donahue Brian S.
Published: May 2014

Objective

Children undergoing congenital cardiac surgery (CCS) are at increased risk for acute kidney injury (AKI) due to a number of factors. Recent evidence suggests AKI may influence mortality beyond the immediate postoperative period and hospitalization. We sought to determine the association between renal failure and longer‐term mortality in children following CCS.

Methods

Our Study population included all patients that underwent cardiac surgery at our institution during a period of 3 years from 2004 through 2006. The primary definition of acute renal injury was based on pRIFLE using estimated creatinine clearance (pRIFLE eCCL).

Results

Predictors of mortality. Age, single ventricle status, and renal failure as defined by pRIFLE stage F were associated with mortality. The hazard ratio for a patient with renal failure as defined by pRIFLE stage F was 3.82 (CI 1.89–7.75). Predictors of AKI as defined by pRIFLE. Duration of cardiopulmonary bypass (CPB) and age were the only variables associated with pRIFLE by univariate analysis. However, in the ordinal or survival model, age was the only variable associated with renal failure as defined by pRIFLE. As patient age increases from 0.30 to 3.5 years, the risks of having renal injury (pRIFLE stage I) or failure (pRIFLE stage F) decreases (OR 0.44, CI 0.21–0.94).

Conclusion

Mortality risk following CCS is increased in younger patients and those experiencing postoperative renal failure as defined by pRIFLE for a period of time that extends well beyond the immediate postoperative period and the time of hospitalization.
Effects of dexmedetomidine on sevoflurane requirement for 50% excellent tracheal intubation in children: a randomized, double‐blind comparison
Authors: He Lin , Wang Xuan , Zheng Shan
Published: May 2014

Objective

We investigated the effects of two dexmedetomidine bolus and infusion combinations on the amount of sevoflurane required to produce 50% excellent tracheal intubation conditions (ED50TI).

Methods

In a prospective, double‐blinded parallel, randomized manner, 60 children (ASA I or II, age 3–8 years) undergoing elective surgery were allocated to one of three groups: saline only (group D0), a bolus dose of 1.0 μg·kg−1 dexmedetomidine followed by a continuous infusion of 0.5 μg·kg−1·h−1 (group D1), or a bolus dose of 2.0 μg·kg−1 dexmedetomidine followed by a continuous infusion of 1.0 μg·kg−1·h−1 (group D2). Each bolus dose of dexmedetomidine was infused over 10 min, after which a dexmedetomidine infusion and 5% sevoflurane were immediately begun, with sevoflurane subsequently adjusted to target specific values determined according to Dixon's up‐and‐down method. After the target concentration of sevoflurane was maintained stable for 15 min, laryngoscopy and tracheal intubation were performed. Intubation was considered excellent only if all subcomponents of the intubation score were rated excellent. Patient enrollment continued until there were six pairs of consecutive patients in which not excellent tracheal intubation conditions were followed by excellent conditions.

Results

The ED50TI of sevoflurane in group D2 (1.41 ± 0.07%) was significantly lower than in group D1 (2.36 ± 0.16%; P < 0.001), the latter being significantly lower than in group D0 (3.52 ± 0.21%; P < 0.001).

Conclusion

Dexmedetomidine infusion produced a dose‐dependent decrease in the ED50TI of sevoflurane in children.
Biofouling impact on production and ecosystem functioning: a review for bivalve aquaculture
Authors: Lacoste Elise , Gaertner‐Mazouni Nabila
Published: May 2014

Bivalve aquaculture is worldwide impacted by biofouling development. Immersed infrastructures and shells of the reared species create new substrate for a wide range of epibionts, mainly composed of suspension feeders. Biofouling development is generally considered as a plague for bivalve aquaculture, and its control results in additional costs that can represent up to 30% of total operational costs of the industry. Epibionts have not only consequences for the species they overgrow (i.e. basibiont), but they can also alter the ecological functioning of the exploited ecosystem. In this review, we point out that the assessment of the net effect of biofouling is more complex than expected, as it combines negative and positive effects on both the commercial production and the ecosystem. Furthermore, we emphasize that the removal of biofouling can be stressful and damaging for the reared species. Biofouling control should be carefully reconsidered, on the basis of a holistic approach considering: (i) the interactions between epibionts and their basibionts; (ii) its impact on the final product; and (iii) its contribution to the sustainability of the ecosystem.
The Significance of Meander Restoration for the Hydrogeomorphology and Recovery of Wetland Organisms in the Kushiro River, a Lowland River in Japan
Authors: Nakamura Futoshi , Ishiyama Nobuo , Sueyoshi Masanao , Negishi Junjiro N. , Akasaka Takumi
Published: May 2014

The meanders and floodplains of the Kushiro River were restored in March 2011. A 1.6‐km stretch of the straightened main channel was remeandered by reconnecting the cutoff former channel and backfilling the straightened reach, and a 2.4‐km meander channel was restored. Additionally, flood levees were removed to promote river–floodplain interactions. There were four objectives of this restoration project: to restore the in‐stream habitat for native fish and invertebrates; to restore floodplain vegetation by increasing flooding frequency and raising the groundwater table; to reduce sediment and nutrient loads in the core wetland areas; to restore a river–floodplain landscape typical to naturally meandering rivers. In this project, not only the natural landscape of a meandering river but also its function was successfully restored. The monitoring results indicated that these goals were likely achieved in the short term after the restoration. The abundance and species richness of fish and invertebrate species increased, most likely because the lentic species that formerly inhabited the cutoff channel remained in the backwater and deep pools created in the restored reach. In addition, lotic species immigrated from neighboring reaches. The removal of flood levees and backfilling of the formerly straightened reach were very effective in increasing the frequency of flooding over the floodplains and raising the water table. The wetland vegetation recovered rapidly 1 year after the completion of the meander restoration. Sediment‐laden floodwater spread over the floodplain, and approximately 80–90% of the fine sediment carried by the water was filtered out by the wetland vegetation.
Principles and Operational Parameters to Optimize Poison Removal with Extracorporeal Treatments
Authors: Bouchard Josée , Roberts Darren M. , Roy Louise , Ouellet Georges , Decker Brian S. , Mueller Bruce A. , Desmeules Simon , Ghannoum Marc
Published: May 2014

A role for nephrologists in the management of a poisoned patient involves evaluating the indications for, and methods of, enhancing the elimination of a poison. Nephrologists are familiar with the various extracorporeal treatments (ECTRs) used in the management of impaired kidney function, and their respective advantages and disadvantages. However, these same skills and knowledge may not always be considered, or applicable, when prescribing ECTR for the treatment of a poisoned patient. Maximizing solute elimination is a key aim of such treatments, perhaps more so than in the treatment of uremia, because ECTR has the potential to reverse clinical toxicity and shorten the duration of poisoning. This manuscript reviews the various principles that govern poison elimination by ECTR (diffusion, convection, adsorption, and centrifugation) and how components of the ECTR can be adjusted to maximize clearance. Data supporting these recommendations will be presented, whenever available.
Cognitive, emotional and social development in adolescents born to substance using women
Authors: Irner Tina Birk , Teasdale Thomas William , Nielsen Tine , Vedal Sissel , Olofsson May
Published: May 2014

The aim of this article is to investigate the long‐term developmental consequences of being born to a substance‐using mother, focusing on cognitive functions, attention, emotional and social development. The longitudinal sample comprised 48 adolescents aged 12–16 at the time of follow‐up assessments, which included the Wechsler Intelligence Scale for Children‐III, the Test of Everyday Attention for Children, The Tower of London test and the Strengths and Difficulties Questionnaire. The adolescents scored significantly lower than the norms on Wechsler's subtests and Full‐Scale IQ, and on The Everyday Attention test. There were few differences on the Strengths and Difficulties Questionnaire. The girls reported significantly more hyperactivity than the British norms, and the teachers reported higher impact scores in boys, compared to the British norms. Thus, the results on cognitive consequences of maternal substance use appear to be very substantial while the emotional and social consequences do not. The results suggest serious negative effects of substance exposure in utero on attention and cognitive functioning in general.
The Role of Help‐Seeking in Preventing Suicide Attempts among Lesbians, Gay Men, and Bisexuals
Authors: Meyer Ilan H. , Teylan Merilee , Schwartz Sharon
Published: May 2014

One possible approach to prevention of suicide attempts is to encourage help‐seeking among individuals at risk. We assessed whether different forms of treatment were associated with lower odds of a suicide attempt in a diverse group of 388 lesbian, gay, and bisexual (LGB) adults aged 18–59, sampled from New York City venues. Of individuals who attempted suicide, 23% sought mental health or medical treatment and 14% sought religious or spiritual treatment prior to the suicide attempt. Black and Latino LGBs were underrepresented in mental health or medical treatment and Black LGBs were overrepresented in religious or spiritual treatment. Seeking mental health or medical treatment was not associated with lower odds of a suicide attempt; seeking religious or spiritual treatment was associated with higher odds of a suicide attempt. We discuss these results and posit hypotheses for further research of this understudied topic.
Microdynamics of Turkey's Export Boom in the 2000s
Authors: Cebeci Tolga , Fernandes Ana M.
Published: May 2014

This paper examines the microdynamics behind the dramatic export boom experienced by Turkey during the 2000s. Using disaggregated exporter‐level customs data covering the universe of export transactions for Turkey during the period 2002–11, we characterise firm‐level dynamics in the export sector and we decompose export growth at the aggregate, sectoral and destination market levels to identify the role of firm turnover, destination turnover and product turnover. We show that year‐to‐year aggregate export growth is dominated by growth in continuous exporters, and for these, growth is dominated by exports to their continued destinations and of their continued products. However, the observed high degree of churning across firms, destinations and products accounts for a substantial part of Turkey's export growth over longer periods. The patterns of microdynamics of export growth are verified across sectors and across groups of destination markets with some exceptions regarding exports to new emerging markets where net exporter entry plays a more critical role for export growth over longer periods.
Spectral domain optical coherence tomography imaging of spectacular ecdysis in the royal python (Python regius)
Authors: Tusler Charlotte A. , Maggs David J. , Kass Philip H. , Paul‐Murphy Joanne R. , Schwab Ivan R. , Murphy Christopher J.
Published: May 2014

Objective

To describe using spectral domain optical coherence tomography (SD‐OCT), digital slit‐lamp biomicroscopy, and external photography, changes in the ophidian cuticle, spectacle, and cornea during ecdysis.

Animals Studied

Four normal royal pythons (Python regius).

Procedures

Snakes were assessed once daily throughout a complete shed cycle using nasal, axial, and temporal SD‐OCT images, digital slit‐lamp biomicroscopy, and external photography.

Results

Spectral domain optical coherence tomography (SD‐OCT) images reliably showed the spectacular cuticle and stroma, subcuticular space (SCS), cornea, anterior chamber, iris, and Schlemm's canal. When visible, the subspectacular space (SSS) was more distended peripherally than axially. Ocular surface changes throughout ecdysis were relatively conserved among snakes at all three regions imaged. From baseline (7 days following completion of a full cycle), the spectacle gradually thickened before separating into superficial cuticular and deep, hyper‐reflective stromal components, thereby creating the SCS. During spectacular separation, the stroma regained original reflectivity, and multiple hyper‐reflective foci (likely fragments from the cuticular‐stromal interface) were noted within the SCS. The cornea was relatively unchanged in character or thickness throughout all stages of ecdysis. Slit‐lamp images did not permit observation of these changes.

Conclusions

Spectral domain optical coherence tomography (SD‐OCT) provided excellent high‐resolution images of the snake anterior segment, and especially the cuticle, spectacle, and cornea of manually restrained normal snakes at all stages of ecdysis and warrants investigation in snakes with anterior segment disease. The peripheral spectacle may be the preferred entry point for diagnostic or therapeutic injections into the SSS and for initiating spectacular surgery.
An integrative approach to assess the phylogeny and the systematics of rounded‐tailed genera of the subfamily Qudsianematinae (Nematoda, Dorylaimida)
Authors: Peña‐Santiago Reyes , Álvarez‐Ortega Sergio
Published: May 2014

The evolutionary relationships of rounded‐tailed dorylaimid genera traditionally classified under the subfamily Qudsianematinae in Qudsianematidae are analysed and discussed with an integrative approach, including morphological features, postembryonic development and D2–D3 expansion segments of 28SrDNAgene sequences. Evidences are provided that support a closer relationship of these genera with members of Dorylaimidae rather than with other representatives of Qudsianematidae. Specifically, remarkable are the changes observed in the morphology of caudal region (tail) during the postembryonic development, with a common pattern: the existence of one or more long‐tailed juvenile stages that result in short, rounded‐tailed adult stage. The new phylogeny derived from such evidences does not match the current classification system, and, consequently, several taxonomic changes are proposed to improve it: eight genera are transferred from Qudsianematidae to Dorylaimidae, the new subfamily Labronematinae is proposed to accommodate them, a new classification in presented for Dorylaimidae, and emended diagnoses are given for the family Dorylaimidae and the subfamily Qudsianematinae.
Molecular phylogeny of the fungus gnat family Diadocidiidae and its position within the infraorder Bibionomorpha (Diptera)
Authors: Ševčík Jan , Kaspřák David , Mantič Michal , Ševčíková Tereza , Tóthová Andrea
Published: May 2014

The molecular phylogeny of the family Diadocidiidae (Diptera: Sciaroidea) is reconstructed based on the combined analysis of four mitochondrial (12S, 16S, COI, cytB) and two nuclear (28S, ITS2) gene markers. All the analyses strongly support Diadocidiidae as a monophyletic group. Genus Diadocidia Ruthe, 1831 includes monophyletic subgenera Diadocidia s. str. and Taidocidia Papp and Ševčík (Acta Zoologica Academiae Scientiarum Hungaricae, 51, 2005b, 329). The monophyly of Adidocidia Laštovka & Matile, 1972 was not confirmed. The position of Diadocidiidae and relationships of the families within the infraorder Bibionomorpha are demonstrated in the analyses based on three gene markers (28S, 12S and 16S). The Bayesian and maximum likelihood analyses of 10 families of Bibionomorpha revealed Sciaridae as the closest relative of Diadocidiidae. Most of the currently recognised extant families of Bibionomorpha proved to be monophyletic. The family Keroplatidae revealed as paraphyletic, with the genera of Macrocerinae being more related to Cecidomyiidae, but the support is low.
Effects of Elastic Modulus Change in Helical Tubes Under the Influence of Dynamic Changes in Curvature and Torsion
Authors: Selvarasu N. K. C. , Tafti Danesh K.
Published: May 2014

The incidence of stent late restenosis is high (Zwart et al., 2010, “Coronary Stent Thrombosis in the Current Era: Challenges and Opportunities for Treatment,” Curr. Treat. Options Cardiovasc. Med., 12(1), pp. 46–57) despite the extensive use of stents, and is most prevalent at the proximal and distal ends of the stent. Elastic modulus change in stented coronary arteries subject to the motion of the myocardium is not studied extensively. It is our objective to understand and reveal the mechanism by which changes in elastic modulus and geometry contribute to the generation of nonphysiological wall shear stress (WSS). Such adverse hemodynamic conditions could have an effect on the onset of restenosis. Three-dimensional (3D), spatiotemporally resolved computational fluid dynamics (CFD) simulations of pulsatile flow with moving wall boundaries and fluid structure interaction (FSI) were carried out for a helical artery with physiologically relevant flow parameters. To study the effect of coronary artery (CA) geometry change on stent elastic modulus mismatch, models where the curvature, torsion and both curvature and torsion change were examined. The elastic modulus is increased by a factor of two, five, and ten in the stented section for all three modes of motion. The changes in elastic modulus and arterial geometry cause critical variations in the local pressure and velocity gradients and secondary flow patterns. The pressure gradient change is  47%, with respect to the unstented baseline when the elastic modulus is increased to 10. The corresponding WSS change is 15.4%. We demonstrate that these changes are attributed to the production of vorticity (vorticity flux) caused by the wall movement and elastic modulus discontinuity. The changes in curvature dominate torsion changes in terms of the effects to local hemodynamics. The elastic modulus discontinuities along with the dynamic change in geometry affected the secondary flow patterns and vorticity flux, which in turn affects the WSS.
Dislocation Density and Grain Size Evolution in the Machining of Al6061-T6 Alloys
Authors: Ding Liqiang , Zhang Xueping , Richard Liu C.
Published: May 2014

This study focuses on addressing the severe plastic deformation (SPD) behavior and the effects of machining parameters on microstructure alternations in machined surface created from high-speed machining. A finite element (FE) model is proposed to predict the orthogonal machining of Al6061-T6 alloys at high speeds. By extracting strains, strain rates, stresses, and temperatures from this model, a dislocation density-based model is incorporated into it as a user-defined subroutine to predict dislocation densities and grain sizes in machined surface. The predicted results show that dislocation densities decrease with the depths below the machined surface, but grain sizes present an opposite tendency. Higher cutting speeds are associated with thinner plastic deformation layers. Dislocation densities decrease with cutting speeds, but grain sizes increase with cutting speeds in machined surface. Dislocation densities decrease initially and then increase with feed rates. There exists a critical feed rate to generate the maximum SPD layer in machined surface. Tool rake angle has a great impact on the depth of plastic deformation layer. Thus, it affects the distributions of dislocation densities and grain sizes. A large negative rake angle can induce an increased dislocation density in machined surface. The predicted chip thicknesses, cutting forces, distributions of dislocation densities, and grain sizes within the range of machining parameters have good agreement with experiments in terms of chip morphology, cutting forces, microstructure, and microhardness in chip and machined surface.
Identification of Machining Process Damping Using Output-Only Modal Analysis
Authors: Ahmadi K. , Altintas Y.
Published: May 2014

The existing chatter stability prediction algorithms fail in low-speed machining of difficult to cut alloys, unless process damping contributed by the tool flank face–finish surface contact is considered. This paper presents a new method in predicting the material dependent process damping coefficient from chatter free orthogonal cutting tests. An equivalent process damping coefficient of the dynamic system is estimated from the frequency domain decomposition (FDD) of the vibration signals measured during stable cutting tests. Subsequently, the specific indentation force of the workpiece material is identified from the process damping coefficients obtained over a range of cutting speeds. The specific indentation force coefficient is used in an explicit formula of process damping which considers the radius and clearance angle of the cutting edge. It is experimentally shown that when the proposed process damping model is included, the accuracy of chatter stability predictions in turning and milling improves significantly at low cutting speeds.
Molecular Dynamics Simulations and Continuum Modeling of Temperature and Strain Rate Dependent Fracture Strength of Graphene With Vacancy Defects
Authors: Dewapriya M. A. N. , Rajapakse R. K. N. D.
Published: May 2014

We investigated the temperature and strain rate dependent fracture strength of defective graphene using molecular dynamics and an atomistic model. This atomistic model was developed by introducing the influence of strain rate and vacancy defects into the kinetics of graphene. We also proposed a novel continuum based fracture mechanics framework to characterize the temperature and strain rate dependent strength of defective sheets. The strength of graphene highly depends on vacancy concentration, temperature, and strain rate. Molecular dynamics simulations, which are generally performed under high strain rates, exceedingly overpredict the strength of graphene at elevated temperatures. Graphene sheets with random vacancies demonstrate a singular stress field as in continuum fracture mechanics. Molecular dynamics simulations on the crack propagation reveal that the energy dissipation rate indicates proportionality with the strength. These findings provide a remarkable insight into the fracture strength of defective graphene, which is critical in designing experimental and instrumental applications.
Parameters Study of Hopf Bifurcation in Railway Vehicle System
Authors: Wu Xingwen , Chi Maoru
Published: May 2014

Roller rig tests were adopted to illustrate two typical types of Hopf bifurcations existing in the railway vehicles. In order to investigate the influence of the vehicles' parameters on the features of Hopf bifurcation, a suspended single wheel set model was formulated. In this model, the lateral and yaw motions of the wheel set were taken into account; Restoring forces between the flange and rail were considered as a smooth function through polynomial fitting; Wheel tread profile was assumed to be conical; Suspension elements and creep forces were considered to be linear properties. The continuation method was utilized to study the features of Hopf bifurcation of the wheel set model. Based on the suspended single wheel set model the effect of the primary suspension, the equivalent conicity of the wheel tread, the mass and spin moment of inertia of the wheel set, and the axle loads on the characteristics of Hopf bifurcation were investigated. Furthermore, the combined effect of parameters was analyzed, and the coupling regions between the parameters were found. In the coupling region, the characteristics of Hopf bifurcation are very sensitive to the variation of the parameters. Therefore, in order to avoid the abrupt change of features of Hopf bifurcation, the coupling region of parameters should be taken into account in the design stage of railway vehicles.
Computational Assessment of Stent Durability Using Fatigue to Fracture Approach
Authors: Jovicic Gordana R. , Vukicevic Arso M. , Filipovic Nenad D.
Published: May 2014

Stents are metal scaffold devices used to maintain lumen and restore blood flow of diseased artery. Despite they brought care of coronary diseases to a new level of efficacy, problem of stent fracture remains unclear even after global needs reached number of 5 × 106 devices yearly. For projected work-life of 10 years, rate of fracture occurrence in stents varies from 5% up to 25% for different designs. Analysis of such miniature devices and long-term events in realistic in vivo conditions remains impossible while experimental in vitro measurements provide limited results consuming much time and expensive equipment. The principal aim of this study was to propose procedure for numerical estimation of coronary stents durability assuming the hyperphysiological pulsatile pressure conditions. The hypothesis was whether the stent durability would be achieved safely for the projected work-life of 10 yr? The procedure was carried out within three phases: (a) initial fatigue analysis based on S-N approach; (b) fatigue lifetime assessment based on fatigue crack growth simulation using Paris power law, and (c) safe-operation, i.e., no-fatigue failure (based on Kitagawa–Takahashi diagram) as well as immediate predictions of the fracture event in the stent. For considered generic stent design, results showed that the stent durability would be achieved safely. Since special diagrams were used, the fatigue risk assessment was clearer compared to the conventional fatigue lifetimes. Moreover, it was found that crack growth was stable for both small and large scale sizes of the crack. Besides the fact that the presented procedure was shown as suitable for numerical assessment of the generic stent durability under hyperphysiological pulsatile pressure conditions, it was concluded that it might be applied for any other design as well as loading conditions. Moreover, it could be efficiently combined with experimental procedures during the process of the stent design validation to reduce manufacturing and testing costs.
Effects of thermal annealing on variations of electron traps in the channel region of amorphous In-Ga-Zn-O thin film transistor
Authors: Hino Aya , Takanashi Yasuyuki , Tao Hiroaki , Morita Shinya , Ochi Mototaka , Goto Hiroshi , Hayashi Kazushi , Kugimiya Toshihiro
Published: May 2014

Photoinduced transient spectroscopy (PITS) was applied to study the effects of thermal annealing in the thin-film transistor (TFT) fabrication process on the variations of the electron traps in the channel region of amorphous In-Ga-Zn-O (a-IGZO). A dominant peak with a maximum of around 130 K was observed in the PITS spectra, but the detailed features were varied depending on the annealing conditions. The six particular temperatures corresponding to the trap states were extracted at about 100, 140, 150, 210, 320, and 390 K from the differential PITS spectra, showing good correlation with the trap states observed in ZnO. The results of thermal desorption spectrometry suggested that the variation of electron traps in the a-IGZO thin films has its origin in the decomposition of O and Zn during the annealing process. The annealing after the etch-stop layer deposition was also examined. The peak at about 150 K extracted from the differential PITS spectra before and after the annealing was markedly decreased. The activation energy of the corresponding trap states was estimated to be around 0.3 eV, which was close to those known as the E3 center in ZnO. Secondary ion mass spectroscopy analysis suggested that the reduction of trap density was mainly due to a decrease in the number of defects which involve hydrogen atoms in their configuration. Considering these results, the variations in the electron traps in the a-IGZO thin films during the TFT fabrication process should be attributed to the introduction of Zn, O, and/or H-related defects into tetrahedra consisting of Zn-O bonds.
A comparison of acoustic and visual metrics of sperm whale longline depredation
Authors: Thode Aaron M. , Wild Lauren , Mathias Delphine , Straley Janice , Lunsford Christopher
Published: May 2014

Annual federal stock assessment surveys for Alaskan sablefish also attempt to measure sperm whale depredation by quantifying visual evidence of depredation, including lip remains and damaged fish. A complementary passive acoustic method for quantifying depredation was investigated during the 2011 and 2012 survey hauls. A combination of machine-aided and human analysis counted the number of distinct “creak” sounds detected on autonomous recorders deployed during the survey, emphasizing sounds that are followed by silence (“creak-pauses”), a possible indication of prey capture. These raw counts were then adjusted for variations in background noise levels between deployments. Both a randomized Pearson correlation analysis and a generalized linear model found that noise-adjusted counts of “creak-pauses” were highly correlated with survey counts of lip remains during both years (2012: r(10) = 0.89, p = 1e-3; 2011: r(39) = 0.72, p = 4e-3) and somewhat correlated with observed sablefish damage in 2011 [r(39) = 0.37, p = 0.03], but uncorrelated with other species depredation. The acoustic depredation count was anywhere from 10% to 80% higher than the visual counts, depending on the survey year and assumptions employed. The results suggest that passive acoustics can provide upper bounds on depredation rates; however, the observed correlation breaks down whenever three or more whales are present.
Planar microphone based on piezoelectric electrospun poly(γ-benzyl-α,L-glutamate) nanofibers
Authors: Ren Kailiang , West James E. , Michael Yu S.
Published: May 2014

Velocity and pressure microphones composed of piezoelectric poly(γ-benzyl-α,L-glutamate) (PBLG) nanofibers were produced by adhering a single layer of PBLG film to a Mylar diaphragm. The device exhibited a sensitivity of −60 dBV/Pa in air, and both pressure and velocity response showed a broad frequency response that was primarily controlled by the stiffness of the supporting diaphragm. The pressure microphone response was ±3 dB between 200 Hz and 4 kHz when measured in a semi-anechoic chamber. Thermal stability, easy fabrication, and simple design make this single element transducer ideal for various applications including those for underwater and high temperature use.
Syllabic reduction in Mandarin and English speech
Authors: Ann Burchfield L. , Bradlow Ann R.
Published: May 2014

This study examined whether language specific properties may lead to cross-language differences in the degree of phonetic reduction. Rates of syllabic reduction (defined here as reduction in which the number of syllables pronounced is less than expected based on canonical form) in English and Mandarin were compared. The rate of syllabic reduction was higher in Mandarin than English. Regardless of language, open syllables participated in reduction more often than closed syllables. The prevalence of open syllables was higher in Mandarin than English, and this phonotactic difference could account for Mandarin's higher rate of syllabic reduction.
Selection of spectral compressive operator for vector Taylor series-based model adaptation in noisy environments
Authors: Baek Soonho , Kang Hong-Goo
Published: May 2014

This letter investigates the impact of spectral compression on the vector Taylor series-based model adaptation algorithm. Unlike mel-frequency cepstral coefficients obtained by the logarithmic compression, the fractional power compression is used for extracting features. Since the relationship between acoustic models for clean and noisy speech depends on nonlinearity of the spectrum, it is important to select an appropriate compressive operator in the model adaptation. In this letter, the dependency of spectral nonlinearity on the speech recognition system is analyzed in various noisy environments. Experimental results confirm that the replacement of the compressive operator improves the performance of the model adaptation.
Maternal Physical Activity During Pregnancy, Child Leisure-Time Activity, and Child Weight Status at 3 to 9 Years
Authors: Mudd Lanay M. , Pivarnik Jim M. , Pfeiffer Karin A. , Paneth Nigel , Chung Hwan , Holzman Claudia
Published: May 2014

Background:

We sought to evaluate the effects of maternal leisure-time physical activity (LTPA) during pregnancy and current child LTPA on child weight status.

Methods:

Women with term pregnancies in the Pregnancy Outcomes and Community Health Study (1998–2004) were followed-up. A race-stratified subset of participants (cohort A) received extensive follow-up efforts leading to better response rates (592/926 = 64%) and diversity. The remainder (Cohort B) had a lower response rate (418/1629 = 26%). Women reported child height, weight and LTPA at 3 to 9 years (inactive vs. active), and recalled pregnancy LTPA (inactive vs. active). A 4-category maternal/child LTPA variable was created (reference: active pregnancy + active child). Children were classified as healthy weight, overweight, or obese using age- and sex-specific Body Mass Index percentiles. Logistic regression was used to assess the odds of child obesity (reference: healthy weight).

Results:

In unadjusted analyses, pregnancy inactivity increased odds for obesity when the child was active (1.6 [95% CI, 1.0−2.6] in Cohort A; 2.1 [95% CI, 1.1−4.0] in Cohort B), and more so when the child was inactive (2.4 [95% CI, 1.2−4.9] in Cohort A; 3.0 [95% CI, 1.0−8.8] in Cohort B). Adjustment for covariates attenuated results to statistical nonsignificance but the direction of relations remained.

Conclusions:

Maternal inactivity during pregnancy may contribute to child obesity risk.
Changes in Meeting Physical Activity Guidelines After Discharge From the Military
Authors: Littman Alyson J. , Jacobson Isabel G. , Boyko Edward J. , Smith Tyler C.
Published: May 2014

Background:

Understanding physical activity (PA) after discharge from the military can inform theory on the role of habit and reinforcement in behavior maintenance and has implications for this population’s future health.

Methods:

Using data from 28,866 Millennium Cohort Study participants (n = 3782 of whom were discharged during the years between assessments), we 1) investigated changes in meeting federal PA guidelines for moderate-to-vigorous activity (MVPA) following military discharge and 2) determined predictors of meeting these guidelines after discharge.

Results:

MVPA declined more in those who were discharged than in those who were not (−17.8 percentage points vs. −2.7 percentage points), with greater declines in former active-duty personnel, those who had deployed with combat exposures, had 14 to 25 years of service, and had been discharged more recently (>2 years prior). In those who were discharged, being normal or overweight (vs. obese), and a nonsmoker or former smoker (vs. current smoker) were positively associated with meeting MVPA Guidelines at follow-up, while meeting MVPA Guidelines at baseline and depression were inversely associated.

Conclusions:

Reductions in MVPA were substantial and unexpected. Increased understanding of transitional periods that may benefit from interventions to mitigate declines in PA will help prevent excess weight gain and physical inactivity-associated health consequences.
A Comparison of Children’s Physical Activity Levels in Physical Education, Recess, and Exergaming
Authors: Gao Zan , Chen Senlin , Stodden David F.
Published: May 2014

Purpose:

To compare young children’s different intensity physical activity (PA) levels in physical education, recess and exergaming programs.

Methods:

Participants were 140 first and second grade children (73 girls; Meanage= 7.88 years). Beyond the daily 20-minute recess, participants attended 75-minute weekly physical education classes and another 75-minute weekly exergaming classes. Children’s PA levels were assessed by ActiGraph GTX3 accelerometers for 3 sessions in the 3 programs. The outcome variables were percentages of time spent in sedentary, light PA and moderate-to-vigorous PA (MVPA).

Results:

There were significant main effects for program and grade, and an interaction effect for program by grade. Specifically, children’s MVPA in exergaming and recess was higher than in physical education. The 2nd-grade children demonstrated lower sedentary behavior and MVPA than the first-grade children during recess; less light PA in both recess and exergaming than first-grade children; and less sedentary behavior but higher MVPA in exergaming than first-grade children.

Conclusions:

Young children generated higher PA levels in recess and exergaming as compared with physical education. Hence, other school-based PA programs may serve as essential components of a comprehensive school PA program. Implications are provided for educators and health professionals.
The Liver Speaks Up in the Sugar Debate
Authors: Price Elvin
Published: May 2014

Even the moderate amount of fructose in a 12-oz can of soda impairs lipid metabolism in the liver of healthy volunteers.
Pentraxin 3 Sends Urinary Tract Infection Down the Drain
Authors: Serezani Henrique
Published: May 2014

The pattern-recognition receptor pentraxin 3 is essential to control uropathogenic
Escherichia coli
infection in the urinary tract.
Science Translational Medicine
Podcast: 14 May 2014
Authors: Sheline Yvette I. , Smith Orla
Published: May 2014

Yvette Sheline discusses an antidepressant drug that decreases amyloid-β in the cerebrospinal fluid of healthy people.
In Vitro
Susceptibility of Equine-Obtained Isolates of Corynebacterium pseudotuberculosis to Gallium Maltolate and 20 Other Antimicrobial Agents
Authors: Norman T. E. , Batista M. , Lawhon S. D. , Zhang S. , Kuskie K. R. , Swinford A. K. , Bernstein L. R. , Cohen N. D.
Published: May 2014

This study's objective was to determine the
in vitro
antimicrobial activities of gallium maltolate (GaM) and 20 other antimicrobial agents against clinical equine isolates of
Corynebacterium pseudotuberculosis
. The growth of cultured isolates was not inhibited by any concentration of GaM. MIC data revealed susceptibility to commonly used antimicrobials.
Influenza Viruses and mRNA Splicing: Doing More with Less
Authors: Dubois Julia , Terrier Olivier , Rosa-Calatrava Manuel
Published: May 2014

During their nuclear replication stage, influenza viruses hijack the host splicing machinery to process some of their RNA segments, the M and NS segments. In this review, we provide an overview of the current knowledge gathered on this interplay between influenza viruses and the cellular spliceosome, with a particular focus on influenza A viruses (IAV). These viruses have developed accurate regulation mechanisms to reassign the host spliceosome to alter host cellular expression and enable an optimal expression of specific spliced viral products throughout infection. Moreover, IAV segments undergoing splicing display high levels of similarity with human consensus splice sites and their viral transcripts show noteworthy secondary structures. Sequence alignments and consensus analyses, along with recently published studies, suggest both conservation and evolution of viral splice site sequences and structure for improved adaptation to the host. Altogether, these results emphasize the ability of IAV to be well adapted to the host’s splicing machinery, and further investigations may contribute to a better understanding of splicing regulation with regard to viral replication, host range, and pathogenesis.