bluuebunny/crossref_metadata_2025_split huggingface dataset:
The flexural strength and fracture toughness of reactive powder concrete in response to changing fibre size and pre‐setting pressure
Authors: İPEK M. 
Published: October 2011

ABSTRACTIn this study, steel fibre mixtures having different compositions of fibres with various sizes were used in reactive powder concrete. The mixture composition, which would present the best performance during the flexural tests, was determined. Pre‐setting pressure tests at six different magnitudes (0, 5, 10, 15, 20, 25 MPa) were conducted on the freshly prepared reactive powder concrete mixture having the determined mixture composition. The 30‐mm‐long steel fibres mixed at a ratio of 4.5% provided the highest flexure strength and the fracture toughness during these tests. The highest pre‐setting pressure was attained at 25 MPa and the flexural strength of the sample increased by 117% reaching 28.07 MPa at that pre‐setting pressure.
A model of cumulative fatigue strengthening effect due to coaxing
Authors: JUN C. , SONG‐LIN Z. , JIN‐ZHI F. , XIN‐TIAN L. 
Published: October 2011

ABSTRACTIn this paper, a fatigue experiment of auto drive shaft smooth specimen is studied in details. Through the analysis of load amplitude and load cycles, which influenced on the residual fatigue strength of structure, we find a mathematical model of strengthening effect due to coaxing. Based on the auto drive shaft work load spectrum, a cumulative fatigue strengthening model is suggested. Then, a new method of lightweight design that can maximise cumulative strengthening effect is proposed. Our model and method can provide a theoretical basis for lightweight design on structural parts of automobiles.
Transcriptional responses of surface water marine microbial assemblages to deep‐sea water amendment
Authors: Shi Yanmei , McCarren Jay , DeLong Edward F. 
Published: October 2011

SummaryDeep‐water nutrient injection in the North Pacific Subtropical Gyre provides an aperiodic yet significant source of inorganic nutrients to the nutrient‐limiting surface waters, and has been implicated in phytoplankton bloom formation. Here we examined short‐term transcriptional responses of surface water picoplankton assemblages in a deep‐sea water (DSW) mixing experiment. Both flow cytometric and transcriptomic analysis indicated stimulation of an Alteromonas‐like population in the DSW‐amended treatment after 12 h, relative to the control. Among the highly expressed alteromonad transcripts in DSW‐treated samples, those encoding genes associated with chemotaxis, cell motility and carbon metabolism were most highly represented, relative to the control. Similarly, Prochlorococcus showed significantly higher levels of transcripts associated with carbon fixation and photosynthesis, as well as slightly increased cell density, relative to the control. Although other microbial taxa did not exhibit enhanced growth, DSW‐stimulated changes in their genome‐wide transcriptional profiles were still readily detectable. Cell‐associated cyanophage DNA and cDNA profiles suggested DSW stimulation of phage‐mediated cell lysis, in previously infected cells. Comparison of the DSW‐responsive Alteromonas populations, to previously reported dissolved organic matter (DOM)‐responding alteromonads (McCarren et al., 2010), revealed differential transcript abundances, predominantly among genes encoding mobile elements and phage‐related genes. Transcript representation in other metabolic pathways differed significantly between Alteromonas populations in the two different treatments, suggesting perturbation‐specific metabolic responses to DSW and DOM. In total, the results provide new insight into short‐term responses of picoplankton to DSW mixing, which occur prior to the more well‐studied, longer‐term growth responses of larger phytoplankton species.
Synergistic metabolism of a broad range of C1 compounds in the marine methylotrophic bacterium HTCC2181
Authors: Halsey Kimberly H. , Carter Amy E. , Giovannoni Stephen J. 
Published: October 2011

SummaryThe 1.3 Mbp genome of HTCC2181, a member of the abundant OM43 clade of coastal bacterioplankton, suggested it is an obligate methylotroph. Preliminary experiments demonstrated that methanol and formaldehyde, but not other common C1 compounds such as methylamine, could support growth. Methanol concentrations in seawater are reportedly < 100 nM, suggesting either that the flux of methanol through plankton pools is very rapid, or that methanol may not be the primary growth substrate for HTCC2181. Therefore, we investigated the apparent extreme substrate range restriction of HTCC2181 in greater detail. Growth rate and maximum cell density of HTCC2181 increased with methanol concentration, yielding a Ks value of 19 µM. In contrast, no growth was observed in the presence of the methylated (C1) compounds, methyl chloride, trimethylamine‐oxide (TMAO) or dimethylsulfoniopropionate (DMSP) when they were the sole substrates. However, growth rate, maximum cell density and cellular ATP content were significantly enhanced when any of these methylated compounds were provided in the presence of a limiting concentration of methanol. These observations fit a model in which the metabolic intermediate formaldehyde is required for net carbon assimilation, allowing C1 substrates that do not produce a formaldehyde intermediate to be oxidized for energy, but not assimilated into biomass. Rates of methanol and TMAO oxidation and assimilation were measured with 14C‐radiolabelled compounds in cultures of HTCC2181 and seawater microbial communities collected off the Oregon coast. The results indicated that in nature as well as in culture, C1 substrates are partitioned between those that are mainly oxidized to produce energy and those that are assimilated. These findings indicate that the combined fluxes of C1 compounds in coastal systems are sufficient to support significant populations of obligate methyltrophs by a metabolic strategy that involves the synergistic metabolism of multiple C1 compounds.
Isolation and characterization of the unicellular diazotrophic cyanobacterium Group C TW3 from the tropical western Pacific Ocean
Authors: Taniuchi Yukiko , Chen Yuh‐ling Lee , Chen Houng‐Yung , Tsai Mei‐Ling , Ohki Kaori 
Published: October 2011

SummaryA unicellular diazotrophic cyanobacterium strain of Group C, designated TW3, was isolated from the oligotrophic Kuroshio Current of the western Pacific Ocean. To our knowledge, this represents the first successful laboratory culture of a Group C unicellular diazotroph from oceanic water. TW3 cells are green rods, 2.5–3.0 µm in width and 4.0–6.0 µm in length. Phylogenetic analyses of both 16S rRNA and nifH gene fragments indicated that the TW3 sequences were over 98% identical to those of the previously isolated Cyanothece sp. ATCC51142 and Gloeocapsa sp., suggesting that TW3 is a member of the Group C unicellular diazotrophs. In addition, both TW3 and Cyanothece sp. ATCC51142 share morphological characteristics; both strains are sheathless and rod‐shaped, display binary fission in a single plane, and possess dispersed thylakoids. TW3 grows aerobically in nitrogen‐deficient artificial seawater, and exhibited the highest observed growth rate of 0.035 h−1 when cultured at 30°C and 140 µmol m−2 s−1 of light intensity. The nitrogen fixation rate, when grown optimally using a 12 h/12 h light–dark cycle, was 7.31 × 10−15 mol N cell−1 day−1. Immunocytochemical staining using Trichodesmium sp. NIBB1067 nitrogenase antiserum revealed the existence of diazotrophic cells sharing morphological characteristics of TW3 in the Kuroshio water from which TW3 was isolated.
A Full Scale Approximation of Covariance Functions for Large Spatial Data Sets
Authors: Sang Huiyan , Huang Jianhua Z. 
Published: October 2011

SummaryGaussian process models have been widely used in spatial statistics but face tremendous computational challenges for very large data sets. The model fitting and spatial prediction of such models typically require O(n3) operations for a data set of size n. Various approximations of the covariance functions have been introduced to reduce the computational cost. However, most existing approximations cannot simultaneously capture both the large- and the small-scale spatial dependence. A new approximation scheme is developed to provide a high quality approximation to the covariance function at both the large and the small spatial scales. The new approximation is the summation of two parts: a reduced rank covariance and a compactly supported covariance obtained by tapering the covariance of the residual of the reduced rank approximation. Whereas the former part mainly captures the large-scale spatial variation, the latter part captures the small-scale, local variation that is unexplained by the former part. By combining the reduced rank representation and sparse matrix techniques, our approach allows for efficient computation for maximum likelihood estimation, spatial prediction and Bayesian inference. We illustrate the new approach with simulated and real data sets.
New Consistent and Asymptotically Normal Parameter Estimates for Random-Graph Mixture Models
Authors: Ambroise Christophe , Matias Catherine 
Published: October 2011

SummaryRandom-graph mixture models are very popular for modelling real data networks. Parameter estimation procedures usually rely on variational approximations, either combined with the expectation–maximization (EM) algorithm or with Bayesian approaches. Despite good results on synthetic data, the validity of the variational approximation is, however, not established. Moreover, these variational approaches aim at approximating the maximum likelihood or the maximum a posteriori estimators, whose behaviour in an asymptotic framework (as the sample size increases to ∞) remains unknown for these models. In this work, we show that, in many different affiliation contexts (for binary or weighted graphs), parameter estimators based either on moment equations or on the maximization of some composite likelihood are strongly consistent and √n convergent, when the number n of nodes increases to ∞. As a consequence, our result establishes that the overall structure of an affiliation model can be (asymptotically) caught by the description of the network in terms of its number of triads (order 3 structures) and edges (order 2 structures). Moreover, these parameter estimates are either explicit (as for the moment estimators) or may be approximated by using a simple EM algorithm, whose convergence properties are known. We illustrate the efficiency of our method on simulated data and compare its performances with other existing procedures. A data set of cross-citations among economics journals is also analysed.
Kalman Filter Initialization for Integrated Population Modelling
Authors: Besbeas Panagiotis , Morgan Byron J. T. 
Published: October 2011

SummaryIn integrated population modelling in ecology, where data from multiple surveys are analysed simultaneously, the Kalman filter may be used to approximate a component likelihood for a state space model of population count data. We evaluate a new method for initiating this Kalman filter, based on a stable age distribution. The new method is illustrated and compared with alternative approaches by application to data on the grey heron. The new method is simple to use, extends naturally to the case of multivariate time series of count data and performs well in a simulation study.
Two-Level Designs of Strength 3 and up to 48 Runs
Authors: Schoen Eric D. , Mee Robert W. 
Published: October 2011

SummaryThe paper will help practitioners to select strength 3 designs that are useful for screening both main effects and two-factor interactions. We calculated word length patterns, correlations of four-factor interaction contrast vectors with the intercept and ranks of the two-factor interaction matrices for all non-equivalent two-level orthogonal arrays of strength 3 and run sizes up to 48. On the basis of these characteristics, there are a limited number of designs that can be recommended for practical use.
Predicting Treatment Efficacy via Quantitative Magnetic Resonance Imaging: A Bayesian Joint Model
Authors: Wu Jincao , Johnson Timothy D. , Galbán Craig J. , Chenevert Thomas L. , Meyer Charles R. , Rehemtulla Alnawaz , Hamstra Daniel A. , Ross Brian D. 
Published: October 2011

SummaryThe prognosis for patients with high grade gliomas is poor, with a median survival of 1 year. Treatment efficacy assessment is typically unavailable until 5–6 months post diagnosis. Investigators hypothesize that quantitative magnetic resonance imaging can assess treatment efficacy 3 weeks after therapy starts, thereby allowing salvage treatments to begin earlier. The purpose of this work is to build a predictive model of treatment efficacy by using quantitative magnetic resonance imaging data and to assess its performance. The outcome is 1-year survival status. We propose a joint, two-stage Bayesian model. In stage I, we smooth the image data with a multivariate spatiotemporal pairwise difference prior. We propose four summary statistics that are functionals of posterior parameters from the first-stage model. In stage II, these statistics enter a generalized non-linear model as predictors of survival status. We use the probit link and a multivariate adaptive regression spline basis. The hybrid Metropolis-within-Gibbs algorithm and reversible jump Markov chain Monte Carlo methods are applied iteratively between the two stages to estimate the posterior distribution. Through both simulation studies and model performance comparisons we find that we can achieve higher overall correct classification rates by accounting for the spatiotemporal correlation in the images and by allowing for a more complex and flexible decision boundary provided by the generalized non-linear model.
Artistic productivity and creative thinking in Parkinson’s disease
Authors: Canesi M. , Rusconi M. L. , Isaias I. U. , Pezzoli G. 
Published: October 2011

Background and purpose:  Creative drive and enhanced artistic‐like production may emerge in patients with Parkinson’s disease (PD) during dopaminergic therapy. However, it has not been described to date whether this artistic‐like production results from dopaminergic drugs triggering innate skills or it could be considered as a repeated behavior possibly associated with impulse control disorders (ICDs).Methods:  We investigated creative drive in a cohort of cognitively preserved patients with PD by means of the Torrance Test of Creative Thinking (TTCT). We also investigated a putative association between creative drive and ICDs in 36 PD patients with (PD‐c) or without (PD‐nc) increased artistic‐like production and 36 healthy controls (HC). We considered artistic‐like productivity to be enhanced if patients reported working on any form of art more than 2 h per day after the introduction of dopaminergic treatment. The TTCT, the Barratt Impulsiveness Scale (BIS‐11A), the Minnesota Impulsive Disorders Interview (MIDI), and the Punding Rating Scale were applied.Results:  Mean TTCT score of PD‐c was found to be similar to HC (169.4 ± 51.6 vs. 170.2 ± 69.7, respectively), and both PD‐c and HC had significantly higher TTCT scores than patients with PD‐nc (125.4 ± 46.1 P < 0.05). TTCT did not correlate with any demographic or clinical data in both PD subgroups. No correlation was found between TTCT, BIS‐11A, and MIDI.Conclusions:  Our study suggests that newly acquired artistic‐like production in patients with PD is not associated with impulsivity or ICDs. Artistic‐like production might represent the emerging of innate skills in a subset of predisposed patients with PD on dopaminergic therapy.
Parenting by anxious mothers: effects of disorder subtype, context and child characteristics
Authors: Murray Lynne , Lau Pui Yi , Arteche Adriane , Creswell Cathy , Russ Stephanie , Zoppa Letizia Della , Muggeo Michela , Stein Alan , Cooper Peter 
Published: October 2011

Background:  There has been increasing research interest in parenting by anxious adults; however, little is known about anxiety‐subtype effects, or effects of the context in which parenting is assessed.Methods:  Two groups of anxious mothers, social phobia (N = 50), generalised anxiety disorder (N = 38), and nonanxious controls (N = 62) were assessed with their 4.9‐year‐old children in three tasks: two presented threat specifically relevant to each maternal disorder, namely, a social threat task where the child had to give a speech, and a nonsocial threat task where the child had to explore potentially scary objects; the third was a nonthreat task (playing with play dough). Seven parenting dimensions were scored. Effects on parenting of maternal anxiety subgroup and task, and their interactions, were examined, as were effects of earlier child behavioural inhibition and currently manifest anxiety.Results:  There were no parenting differences between maternal groups in the nonthreat play‐dough task; parenting difficulties in the two anxious groups were principally evident in the disorder‐specific challenge. Parenting differences between nonanxious and anxious mothers occurred independently of child characteristics. There was little evidence for particular forms of parenting difficulty being unique to maternal disorder.Conclusions:  Anxious mothers’ parenting difficulties emerge when occurring under challenge, especially when this is disorder‐specific. These effects should be considered in research and clinical practice.
Training and learning robotic surgery, time for a more structured approach: a systematic review
Authors: Schreuder HWR , Wolswijk R , Zweemer RP , Schijven MP , Verheijen RHM 
Published: October 2011

Please cite this paper as: Schreuder H, Wolswijk R, Zweemer R, Schijven M, Verheijen R. Training and learning robotic surgery, time for a more structured approach: a systematic review. BJOG 2012;119:137–149.Background  Robotic assisted laparoscopic surgery is growing rapidly and there is an increasing need for a structured approach to train future robotic surgeons.Objectives  To review the literature on training and learning strategies for robotic assisted laparoscopic surgery.Search strategy  A systematic search of MEDLINE, EMBASE, the Cochrane Library and the Journal of Robotic Surgery was performed.Selection criteria  We included articles concerning training, learning, education and teaching of robotic assisted laparoscopic surgery in any specialism.Data collection and analysis  Two authors independently selected articles to be included. We categorised the included articles into: training modalities, learning curve, training future surgeons, curriculum design and implementation.Main results  We included 114 full text articles. Training modalities such as didactic training, skills training (dry lab, virtual reality, animal or cadaver models), case observation, bedside assisting, proctoring and the mentoring console can be used for training in robotic assisted laparoscopic surgery. Several training programmes in general and specific programmes designed for residents, fellows and surgeons are described in the literature. We provide guidelines for development of a structured training programme.Authors’ conclusions  Robotic surgical training consists of system training and procedural training. System training should be formally organised and should be competence based, instead of time based. Virtual reality training will play an import role in the near future. Procedural training should be organised in a stepwise approach with objective assessment of each step. This review aims to facilitate and improve the implementation of structured robotic surgical training programmes.
Catecholamines up integrates dopamine synthesis and synaptic trafficking
Authors: Wang Zhe , Ferdousy Faiza , Lawal Hakeem , Huang Zhinong , Daigle J. Gavin , Izevbaye Iyare , Doherty Olugbenga , Thomas Jerrad , Stathakis Dean G , O’Donnell Janis M. 
Published: October 2011

J. Neurochem. (2011) 10.1111/j.1471‐4159.2011.07517.xAbstractThe highly reactive nature of dopamine renders dopaminergic neurons vulnerable to oxidative damage. We recently demonstrated that loss‐of‐function mutations in the Drosophila gene Catecholamines up (Catsup) elevate dopamine pools but, paradoxically, also confer resistance to paraquat, an herbicide that induces oxidative stress‐mediated toxicity in dopaminergic neurons. We now report a novel association of the membrane protein, Catsup, with GTP cyclohydrolase rate‐limiting enzyme for tetrahydrobiopterin (BH4) biosynthesis and tyrosine hydroxylase, rate‐limiting enzyme for dopamine biosynthesis, which requires BH4 as a cofactor. Loss‐of‐function Catsup mutations cause dominant hyperactivation of both enzymes. Elevated dopamine levels in Catsup mutants coincide with several distinct characteristics, including hypermobility, minimal basal levels of 3,4‐dihydroxy‐phenylacetic acid, an oxidative metabolite of dopamine, and resistance to the vesicular monoamine transporter inhibitor, reserpine, suggesting that excess dopamine is synaptically active and that Catsup functions in the regulation of synaptic vesicle loading and release of dopamine. We conclude that Catsup regulates and links the dopamine synthesis and transport networks.
Neuronal Nogo‐A regulates glutamate receptor subunit expression in hippocampal neurons
Authors: Peng Xiangmin , Kim Jeeyong , Zhou Zhigang , Fink David J. , Mata Marina 
Published: October 2011

J. Neurochem. (2011) 10.1111/j.1471‐4159.2011.07520.xAbstractNogo‐A and its cognate receptor NogoR1 (NgR1) are both expressed in neurons. To explore the function of these proteins in neurons of the CNS, we carried out a series of studies using postnatal hippocampal neurons in culture. Interfering with the binding of Nogo‐A to NgR1 either by adding truncated soluble fragment of NgR1 (NgSR) or by reducing NgR1 protein with a specific siRNA, resulted in a marked reduction in Nogo‐A expression. Inhibition of Rho‐ROCK or MEK‐MAPK signaling resulted in a similar reduction in neuronal Nogo‐A mRNA and protein. Reducing Nogo‐A protein levels by siRNA resulted in an increase in the post‐synaptic scaffolding protein PSD95, as well as increases in GluA1/GluA2 AMPA receptor and GluN1/GluN2A/GluN2B NMDA glutamate receptor subunits. siRNA treatment to reduce Nogo‐A resulted in phosphorylation of mTOR; addition of rapamycin to block mTOR signaling prevented the up‐regulation in glutamate receptor subunits. siRNA reduction of NgR1 resulted in increased expression of the same glutamate receptor subunits. Taken together the results suggest that transcription and translation of Nogo‐A in hippocampal neurons is regulated by a signaling through NgR1, and that interactions between neuronal Nogo‐A and NgR1 regulate glutamatergic transmission by altering NMDA and AMPA receptor levels through an rapamycin‐sensitive mTOR‐dependent translation mechanism.