bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sea urchin spermatozoa generate at least two reactive oxygen species; the type of reactive oxygen species changes under different conditions
Authors: Kazama Makoto , Hino Akiya 
Published: January 2012

AbstractReactive oxygen species (ROS) cause oxidative stress and act as signal transduction molecules in many cells. Spermatozoa from several mammals generate ROS, which are involved in male infertility and signaling during capacitation. In the present study, we investigated ROS generation by sea urchin spermatozoa at the initiation of motility, during dilution with seawater, and following egg jelly treatment. In seawater containing an ROS indicator, 5‐(and 6‐)chloromethyl‐2′,7′‐dichlorodihydrofluorescein diacetate (CM‐H2DCFDA), fluorescence increased after the addition of spermatozoa. The ROS generation rate was dependent upon the dilution ratio and respiratory rate of the spermatozoa. Spermatozoa in sodium‐free seawater did not increase fluorescence, but fluorescence did increase with the addition of NaCl. Sodium chloride also led to the initiation of sperm motility and respiration. Using the indicator MitoSOX Red, ROS generation was detected from spermatozoa exposed to egg jelly dissolved in seawater, but not in normal seawater. Moreover, the respiratory inhibitor antimycin A prevented CM‐H2DCFDA‐detectable ROS and increased MitoSox‐detectable ROS at a higher concentration. These findings revealed that the ROS generated were of different species, possibly hydrogen peroxide (H2O2) and superoxide anion (${\rm O}_{{\rm 2}}^{- } $), and their detected levels were altered by egg jelly. We concluded that sea urchin spermatozoa generate at least two species of ROS depending on the physiological conditions to which they are exposed. It is possible that the major ROS from sea urchin spermatozoa changes during the course of fertilization. Mol. Reprod. Dev. 79: 283–295, 2012. © 2012 Wiley Periodicals, Inc.
In vivo waveguide elastography of white matter tracts in the human brain
Authors: Romano Anthony , Scheel Michael , Hirsch Sebastian , Braun Jürgen , Sack Ingolf 
Published: January 2012

AbstractWhite matter is composed primarily of myelinated axons which form fibrous, organized structures and can act as waveguides for the anisotropic propagation of sound. The evaluation of their elastic properties requires both knowledge of the orientation of these waveguides in space, as well as knowledge of the waves propagating along and through them. Here, we present waveguide elastography for the evaluation of the elastic properties of white matter tracts in the human brain, in vivo, using a fusion of diffusion tensor imaging, magnetic resonance elastography, spatial‐spectral filtering, a Helmholtz decomposition, and anisotropic inversions, and apply this method to evaluate the material parameters of the corticospinal tracts of five healthy human volunteers. We begin with an Orthotropic inversion model and demonstrate that redundancies in the solution for the nine elastic coefficients indicate that the corticospinal tracts can be approximated by a Hexagonal model (transverse isotropy) comprised of five elastic coefficients representative of a medium with fibers aligned parallel to a central axis, and provides longitudinal and transverse wave velocities on the order of 5.7 m/s and 2.1 m/s, respectively. This method is intended as a new modality to assess white matter structure and health by means of the evaluation of the anisotropic elasticity tensor of nerve fibers. Magn Reson Med, 2012. © 2012 Wiley Periodicals, Inc.
Multigrid methods for two‐player zero‐sum stochastic games
Authors: Akian Marianne , Detournay Sylvie 
Published: January 2012

SUMMARYWe present a fast numerical algorithm for large scale zero‐sum stochastic games with perfect information, which combines policy iteration and algebraic multigrid methods. This algorithm can be applied either to a true finite state space zero‐sum two‐player game or to the discretization of an Isaacs equation. We present numerical tests on discretizations of Isaacs equations or variational inequalities. We also present a full multilevel policy iteration, similar to full multigrid algorithm (FMG), which allows one to improve substantially the computation time for solving some variational inequalities. Copyright © 2012 John Wiley & Sons, Ltd.
Polymerizable ionic liquids for the preparation of polystyrene/clay composites
Authors: Pucci Andrea , Liuzzo Vincenzo , Melai Bernardo , Pomelli Christian Silvio , Chiappe Cinzia 
Published: January 2012

AbstractPolymerizable ionic liquids (ILs) 1‐methyl‐3‐(4‐vinylbenzyl)imidazolium chloride, 1‐hexyl‐3‐(4‐vinylbenzyl)imidazolium chloride and 1‐dodecyl‐3‐(4‐vinylbenzyl)imidazolium chloride were prepared and used as new surfactants for the modification of montmorillonite (MMT). Functionalized MMTs were prepared by cationic exchange between sodium MMT and each of the ILs. Polystyrene (PS)/MMT composites were subsequently prepared by in situ intercalative free radical polymerization of styrene containing dispersed organophilic MMT. Exfoliation of MMT in the PS matrix was achieved only for MMT functionalized with the 1‐dodecyl‐3‐(4‐vinylbenzyl)imidazolium‐based IL as revealed by X‐ray diffraction and electron microscopy. The exfoliated composites showed good transparency and higher decomposition temperature than virgin polymer matrix, particularly pronounced under air atmosphere (ΔTmax = 66 °C), data comparable to or even greater than those reported in the literature for exfoliated PS nanocomposites. Copyright © 2012 Society of Chemical Industry
3‐D optical modeling of thin‐film silicon solar cells on diffraction gratings
Authors: Isabella Olindo , Solntsev Serge , Caratelli Diego , Zeman Miro 
Published: January 2012

ABSTRACTAn effective rigorous 3‐D optical modeling of thin‐film silicon solar cells based on finite element method (FEM) is presented. The simulation of a flat single junction thin‐film silicon solar cell on thick glass (i.e., superstrate configuration) is used to validate a commercial FEM‐based package, the High Frequency Structure Simulator (HFSS). The results are compared with those of the reference software, Advanced Semiconductor Analysis (ASA) program, proving that the HFSS is capable of correctly handling glass as an incident material within very timely, short, and numerically stable calculations. By using the HFSS, we simulated single junction thin‐film silicon solar cells on glass substrates textured with one‐dimensional (1‐D) and two‐dimensional (2‐D) trapezoid‐shaped diffraction gratings. The correctness of the computed results, with respect to an actual device, is discussed, and the impact of different polarizations on spectral response and optical losses is examined. From the simulations carried out, optimal combinations for period and height in both 1‐D and 2‐D grating configurations can be indicated, leading to short‐circuit current percentage increase with respect to a flat cell of, respectively, 25.46% and 32.53%. With very limited computer memory usage and computational time in the order of tens of minutes for a single simulation, we promote the usage of 3‐D FEM as a rigorous and efficient way to simulate thin‐film silicon solar cells. Copyright © 2012 John Wiley & Sons, Ltd.
Making visible teacher reports of their teaching experiences: The Early Childhood Teacher Experiences Scale
Authors: Fantuzzo John , Perlman Staci , Sproul Faith , Minney Ashley , Perry Marlo A. , Li Feifei 
Published: January 2012

AbstractThe study developed multiple independent scales of early childhood teacher experiences (ECTES). ECTES was co‐constructed with preschool, kindergarten, and first grade teachers in a large urban school district. Demographic, ECTES, and teaching practices data were collected from 584 teachers. Factor analyses documented three teacher experience constructs: Teacher Efficacy, Job Stress, and School Support. Findings showed differences in teaching practices based on ECTES dimensions in hypothesized directions. Teachers experiencing higher levels of stress spent less time teaching literacy and numeracy and interacting with parents, whereas teachers experiencing higher levels of efficacy spent increased time teaching both cognitive skills and social‐emotional skills and communicating with parents. Analyses of program differences in these measures showed that first grade teachers reported the highest level of stress and that kindergarten and Head Start teachers were more likely to feel efficacious than were first grade teachers or other preschool teachers in child care settings. © 2011 Wiley Periodicals, Inc.
A comparison of the mystery motivator and theGet 'Em On Taskinterventions for off‐task behaviors
Authors: Kraemer Elisabeth E. , Davies Susan C. , Arndt Kelli Jo , Hunley Sawyer 
Published: January 2012

AbstractAttending to instruction is a critical behavior for academic success. Many elementary school teachers, however, identify disruptive and inattentive classroom behaviors as key barriers to students' successful educational performance. This study examined the impact of two class‐wide positive behavior support programs. The Mystery Motivator andGet 'Em On Taskinterventions were implemented in an alternating treatments design with fifth grade participants to decrease off‐task behaviors. Results indicated that both interventions effectively decreased off‐task behavior at the class‐wide level. Implications and suggestions for future research on evidence‐based behavioral interventions are discussed. © 2011 Wiley Periodicals, Inc.
Stereoselective synthesis of fully protected (2S,4S,6S)‐2‐amino‐6‐hydroxy‐4‐methyl‐8‐oxodecanoic acid (AHMOD)
Authors: Zhang Wei , Li Xiangpeng , Ding Ning , Li Yingxia 
Published: January 2012

AbstractThe stereocontrolled synthesis of fully protected (2S,4S,6S)‐2‐amino‐6‐hydroxy‐4‐methyl‐8‐oxodecanoic acid was accomplished using a glutamate derivative as starting material. The key steps of this stereochemical synthetic pathway involved an Evans asymmetric alkylation, a Sharpless asymmetric epoxidation, and a Grignard reaction. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.
A Robustness Approach to Reliability
Authors: Johannesson Pär , Bergman Bo , Svensson Thomas , Arvidsson Martin , Lönnqvist Åke , Barone Stefano , de Maré Jacques 
Published: January 2012

Reliability of products is here regarded with respect to failure avoidance rather than probability of failure. To avoid failures, we emphasize variation and suggest some powerful tools for handling failures due to variation. Thus, instead of technical calculation of probabilities from data that usually are too weak for correct results, we emphasize the statistical thinking that puts the designers focus on the critical product functions.Making the design insensitive to unavoidable variation is called robust design and is handled by (i) identification and classification of variation, (ii) design of experiments to find robust solutions, and (iii) statistically based estimations of proper safety margins.Extensions of the classical failure mode and effect analysis (FMEA) are presented. The first extension consists of identifying failure modes caused by variation in the traditional bottom–up FMEA analysis. The second variation mode and effect analysis (VMEA) is a top–down analysis, taking the product characteristics as a starting point and analyzing how sensitive these characteristics are to variation.In cases when there is sufficient detailed information of potential failure causes, the VMEA can be applied in its most advanced mode, the probabilistic VMEA. Variation is then measured as statistical standard deviations, and sensitivities are measured as partial derivatives. This method gives the opportunity to dimension tolerances and safety margins to avoid failures caused by both unavoidable variation and lack of knowledge regarding failure processes. Copyright © 2012 John Wiley & Sons, Ltd.
Rotational capacity of castellated steel beams
Authors: Daryan Amir Saedi , Sadri Mohammadreza , Saberi Hamid , Saberi Vahid , Moghadas Ahmad Baleh , Karimlu Mohammadjavad 
Published: January 2012

SUMMARYThis paper numerically studies the behavior of castellated beams with two simply supported ends under moment gradient loading and investigates the effect of beam and braced lengths on rotational capacity of castellated beams. To assure the ability of numerical models in predicting the complex behavior (especially at the location of opening) as well as the failure modes, numerical models of two experimentally tested specimens are developed. Comparison of force–displacement curves and failure modes shows that neglecting the boundary condition of the specimens, the numerical method can properly predict the behavior of castellated beams. All geometrical properties of the beams are the same as the study parameters so that the finite element model of the corresponding plain‐webbed beams can be easily created by filling the web openings in castellated beams. The accuracy of finite element models of plain‐webbed beams is evaluated by comparing the moment–rotation behavior with that of numerical models developed by other researchers. Rotational capacity of castellated beams derived from numerical models is compared with that of the corresponding I‐shaped plain‐webbed steel beams, and it is observed that in the case of short beams, web openings reduce energy absorption and plastic moment capacity of the beams compared with that of long ones. Copyright © 2012 John Wiley & Sons, Ltd.
Mechanisms of cerebellar contributions to cognition in humans
Authors: Bellebaum Christian , Daum Irene , Suchan Boris 
Published: January 2012

AbstractThe role of the human cerebellum in cognitive processes is the subject of ongoing debate. On the basis of neuroanatomical findings of closed cerebro‐cerebellar loops in monkeys, which originate not only in motor but also in nonmotor regions of the cerebral cortex, this article addresses mechanisms of the involvement of the human cerebellum in two well‐studied cognitive domains, executive function, working memory in particular, and associative learning, with special emphasis on the nature of a potential cerebellar contribution to these cognitive processes. The uniform organization of cortico‐cerebellar connections suggests parallels in cerebellar information processing in motor‐ and nonmotor contexts. Taking into account recent models on cerebellar function, it is suggested that the main contribution of the cerebellum to motor as well as to cognitive tasks may be to provide accurate predictions of future sensations, actions, and events. WIREs Cogn Sci 2012, 3:171–184. doi: 10.1002/wcs.1161This article is categorized under:

Neuroscience > Cognition
Object‐based attention: strategy versus automaticity
Authors: Shomstein Sarah 
Published: January 2012

AbstractThis article begins with a description of space‐ and object‐based guidance of attentional selection. It goes on to discuss the most influential, two‐rectangle, paradigm for demonstrating the existence of space‐ and object‐based attentional effects. The article then considers two different mechanisms, attentional spreading and attentional prioritization, that can potentially explain how object representations come to guide attentional selection. Finally, it discusses several empirical findings that have emerged in support of the two different mechanisms. It concludes by putting forth a new framework for investigating object‐based effects. WIREs Cogn Sci 2012, 3:163–169. doi: 10.1002/wcs.1162This article is categorized under:

Psychology > Attention
Effects of browsing by sika deer (Cervus nippon) on subalpine vegetation at Mt. Kita, central Japan
Authors: Nagaike Takuo 
Published: January 2012

AbstractThe effects of browsing by sika deer (Cervus nippon) on subalpine vegetation (Betula forests and tall grasslands) were investigated in the South Alps National Park, Japan. The browsing ratio (the number of browsed quadrats to the number of quadrats occurring in each plot) was significantly higher in Betula forests than in grasslands. A significant negative correlation was found between the browsing ratio and some species diversity indices (number of species and the Shannon–Wiener diversity index) in the Betula forests, but not in grasslands. The frequency of occurrence and the number of preferred browse species were significantly higher in Betula forests than in grasslands. Browsing was not always the most serious on the most frequent vegetation. For example, Polemonium caeruleum L. subsp. yezoense var. nipponicum, which is listed as vulnerable on Japan's red list of threatened species and was low in occurrence in Betula forests compared to grasslands, was more browsed in Betula forests than in grasslands. Less frequently occurring species subjected to more browsing could easily disappear. The disappearance of such species would exert a strong effect on the species pool in the area.
Plasma Phospholipid Fatty Acid and Ex Vivo Neutrophil Responses are Differentially Altered in Dogs Fed Fish‐ and Linseed‐Oil Containing Diets at the Same n‐6:n‐3 Fatty Acid Ratio
Authors: Waldron Mark K. , Hannah Steven S. , Bauer John E. 
Published: January 2012

AbstractThe effect of diets containing either 18‐carbon n‐3 fatty acids (FA) or 20/22‐carbon n‐3 FA on canine plasma and neutrophil membrane fatty acid composition, superoxide and leukotriene B4 and B5 production when fed at the same n‐6:n‐3 fatty acid ratio was investigated. Four groups of ten dogs each were fed a low fat basal diet supplemented with safflower oil (SFO), beef tallow (BTO), linseed oil (LSO), or Menhaden fish oil (MHO) for 28 days. Dietary fat provided 40.8% of energy and the n‐6:n‐3 of the diets were ~100:1, 9.7:1, 0.38:1, and 0.34:1 for the SFO, BTO, LSO and MHO groups, respectively. The MHO and LSO groups had increased incorporation of EPA and DPA in both the plasma and neutrophil membranes compared to the BTO and SFO groups. DHA was observed in the MHO but not in the LSO group. Neutrophils from the MHO diet fed dogs had less LTB4 and greater LTB5 than the other three groups. The LSO group also showed a reduction in LTB4 and greater LTB5 production compared to the SFO and BTO groups. Both LSO and MHO groups had lower superoxide production compared to the SFO and BTO groups. Diets containing 18 or 20/22 carbon n‐3 FA fed at the same n‐6:n‐3 resulted in differential incorporation of long chain n‐3 FA into neutrophil membranes. Thus, fatty acid type and chain length individually affect neutrophil membrane structure and function and these effects exist independent of dietary total n‐6:total n‐3 FA ratios.
Fully resolved numerical simulation of particle-laden turbulent flow in a horizontal channel at a low Reynolds number
Authors: Shao Xueming , Wu Tenghu , Yu Zhaosheng 
Published: January 2012

AbstractA fictitious domain method is used to perform fully resolved numerical simulations of particle-laden turbulent flow in a horizontal channel. The effects of large particles of diameter 0.05 and 0.1 times the channel height on the turbulence statistics and structures are investigated for different settling coefficients and volume fractions (0.79 %–7.08 %) for the channel Reynolds number being 5000. The results indicate the following. (a) When the particle sedimentation effect is negligible (i.e. neutrally buoyant), the presence of particles decreases the maximum r.m.s. of streamwise velocity fluctuation near the wall by weakening the intensity of the large-scale streamwise vortices, while increasing the r.m.s. of the streamwise fluctuating velocity in the region very close to the wall and in the centre region. On the other hand, the particles increase the r.m.s. of transverse and spanwise fluctuating velocities in the near-wall region by inducing the small-scale vortices. (b) When the particle settling effect is so substantial that most particles settle onto the bottom wall and form a particle sediment layer (SL), the SL plays the role of a rough wall and parts of the vortex structures shedding from the SL ascend into the core region and substantially increase the turbulence intensity there. (c) When the particle settling effect is moderate, the effects of particles on the turbulence are a combination of the former two situations, and the Shields number is a good parameter for measuring the particle settling effects (i.e. the particle concentration distribution in the transverse direction). The average velocities of the particle are smaller in the lower half-channel and larger in the upper half-channel compared to the local fluid velocities in the presence of gravity effects. The effects of the smaller particles on the turbulence are found to be stronger at the same particle volume fractions.
Rarefied gas flow around a sharp edge induced by a temperature field
Authors: Taguchi Satoshi , Aoki Kazuo 
Published: January 2012

AbstractA rarefied gas flow thermally induced around a heated (or cooled) flat plate, contained in a vessel, is considered in two different situations: (i) both sides of the plate are simultaneously and uniformly heated (or cooled); and (ii) only one side of the plate is uniformly heated. The former is known as the thermal edge flow and the latter, typically observed in the Crookes radiometer, may be called the radiometric flow. The steady behaviour of the gas induced in the container is investigated on the basis of the Bhatnagar–Gross–Krook (BGK) model of the Boltzmann equation and the diffuse reflection boundary condition by means of an accurate finite-difference method. The flow features are clarified for a wide range of the Knudsen number, with a particular emphasis placed on the structural similarity between the two flows. The limiting behaviour of the flow as the Knudsen number tends to zero (and thus the system approaches the continuum limit) is investigated for both flows. The detailed structure of the normal stress on the plate as well as the cause of the radiometric force (the force acting on the plate from the hotter to the colder side) is also clarified for the present infinitely thin plate.
Equity Mispricing and Leverage Adjustment Costs
Authors: Warr Richard S. , Elliott William B. , Koëter-Kant Johanna , Öztekin Özde 
Published: January 2012

AbstractWe find that equity mispricing impacts the speed at which firms adjust to their target leverage (TL) and does so in predictable ways depending on whether the firm is over- or underlevered. For example, firms that are above their TL and should therefore issue equity (or retire debt) adjust more rapidly toward their target when their equity is overvalued. However, when a firm is undervalued but needs to reduce leverage, the speed of adjustment is much slower. Our findings support the role of equity mispricing as an important factor that alters the cost of making capital structure adjustments.