bluuebunny/crossref_metadata_2025_split huggingface dataset:
A comparative study on low‐order, amplitude‐equation and perturbation approaches in thermal convection
Authors: Albaalbaki Bashar , Khayat Roger E. 
Published: September 2011

SUMMARYA comparison among three weakly nonlinear approaches for thermo‐gravitational instability in a Newtonian fluid layer heated from below is presented. First, the dynamical systems describing the time evolution of the problem from different weakly nonlinear approaches, namely, the Lorenz model, the amplitude equations and the perturbation expansion approaches are obtained. Next, the steady states and their stability, as well as the transient behaviour are obtained from each dynamical system. The similarity and difference among the three models are emphasized. The role of each of the nondimensional groups, the Rayleigh number and the Prandtl number is compared for the three models. The different approaches lead to similar behaviours when the Rayleigh number is just above its critical value and Prandtl number is high. However, only the dynamical system obtained from the amplitude equations is able to reflect the role of the Prandtl number. On the other hand, the amplitude equations and perturbation expansion techniques are not suitable for predicting the uniform oscillatory behaviour observed frequently in Rayleigh–Bénard convection. The novelty of the current work lies in studying the critical differences in the findings of the three popular approaches to investigate weakly nonlinear thermal convection for the first time. Copyright © 2011 John Wiley & Sons, Ltd.
Direct numerical simulation of decaying two‐dimensional turbulence in a no‐slip square box using smoothed particle hydrodynamics
Authors: Robinson Martin , Monaghan Joseph J. 
Published: September 2011

SUMMARYThis paper explores the application of SPH to a DNS of decaying turbulence in a two‐dimensional no‐slip wall‐bounded domain. In this bounded domain, the inverse energy cascade, and a net torque exerted by the boundary, results in a spontaneous spin‐up of the fluid, leading to a typical end state of a large monopole vortex that fills the domain. The SPH simulations were compared against published results using a high‐accuracy pseudo‐spectral code. Ensemble averages of the kinetic energy, enstrophy and average vortex wavenumber compared well against the pseudo‐spectral results, as did the evolution of the total angular momentum of the fluid. However, although the pseudo‐spectral results emphasised the importance of the no‐slip boundaries as generators of long‐lived coherent vortices in the flow, no such generation was seen in the SPH results. Vorticity filaments produced at the boundary were always dissipated by the flow shortly after separating from the boundary layer. The kinetic energy spectrum of the SPH results was calculated using an SPH Fourier transform that operates directly on the disordered particles. The ensemble kinetic energy spectrum showed the expected k−3 scaling over most of the inertial range. However, the spectrum flattened at smaller length scales (initially less than 7.5 particle spacings and growing in size over time), indicating an excess of small‐scale kinetic energy.Copyright © 2011 John Wiley & Sons, Ltd.
Numerical study of breaking waves by a two‐phase flow model
Authors: Xie Zhihua 
Published: September 2011

SUMMARYA two‐phase flow model, which solves the flow in the air and water simultaneously, is presented for modelling breaking waves in deep and shallow water, including wave pre‐breaking, overturning and post‐breaking processes. The model is based on the Reynolds‐averaged Navier–Stokes equations with the k −ε turbulence model. The governing equations are solved by the finite volume method in a Cartesian staggered grid and the partial cell treatment is implemented to deal with complex geometries. The SIMPLE algorithm is utilised for the pressure‐velocity coupling and the air‐water interface is modelled by the interface capturing method via a high resolution volume of fluid scheme. The numerical model is validated by simulating overturning waves on a sloping beach and over a reef, and deep‐water breaking waves in a periodic domain, in which good agreement between numerical results and available experimental measurements for the water surface profiles during wave overturning is obtained. The overturning jet, air entrainment and splash‐up during wave breaking have been captured by the two‐phase flow model, which demonstrates the capability of the model to simulate free surface flow and wave breaking problems.Copyright © 2011 John Wiley & Sons, Ltd.
THE EFFECTS OF INSURANCE MANDATES ON CHOICES AND OUTCOMES IN INFERTILITY TREATMENT MARKETS
Authors: Hamilton Barton H. , McManus Brian 
Published: September 2011

SUMMARYFor the 10% to 15% of American married couples who experience reproductive problems, in vitro fertilization (IVF) is the leading technologically advanced treatment procedure. However, IVF's expense may prevent many couples from receiving treatment, and those who are treated may take an overly aggressive approach to reduce the probability of failure. Aggressive treatment, which occurs through an increase in the number of embryos transferred during IVF, can lead to medically dangerous multiple births. We evaluated the principle policy proposal—insurance mandates—for improving IVF access and outcomes. We used data from US markets during 1995–2003 to show that broad insurance mandates for IVF result in not only large increases in treatment access but also significantly less aggressive treatment. More limited insurance mandates, which may apply to a subset of insurers or provide weaker guidelines for insurer behavior, generally have little effect on IVF markets. Copyright © 2011 John Wiley & Sons, Ltd.
THE EFFECT OF TAIWAN'S NATIONAL HEALTH INSURANCE ON MORTALITY OF THE ELDERLY: REVISITED
Authors: Chang Simon 
Published: September 2011

SUMMARYA recent paper estimates the effects of Taiwan's National Health Insurance (NHI) on the elderly and concludes that NHI greatly increased the medical care utilization of the elderly but did not reduce their mortality. Using more recent and more accurate mortality data of the same group of elderly, this note re‐estimates the NHI effect on mortality and finds that the mortality hazard of the previously uninsured elderly in the post‐NHI period was on average 24% lower than it would have been in the absence of NHI. However, the NHI effect on the mortality hazard is only evident in the first 6 years following the enactment of NHI, suggesting that it may be difficult to undo the damage caused by the lack of insurance in early life. Copyright © 2011 John Wiley & Sons, Ltd.
Upper aerodigestive tract neurofunctional mechanisms: Lifelong evolution and exercise
Authors: Robbins JoAnne 
Published: September 2011

AbstractThe transformation of the upper aerodigestive tract – oral cavity, pharynx, and larynx – serves the functions of eating, speaking, and breathing during sleeping and waking hours. These life‐sustaining functions may be produced by a central neural sensorimotor system that shares certain neuroanatomic networks while maintaining separate neural functional systems and network structures. Current understanding of development, maturation, underlying neural correlates, and integrative factors are discussed in light of currently available imaging modalities and recently emerging interventions. Exercise and an array of additional treatments together seem to provide promising translational pathways for evidence‐based innovation, novel habilitation, and rehabilitation strategies and delay, or even prevent neuromuscular decline cross‐cutting functions and supporting quality of life throughout increasingly enduring lifespans. © 2011 Wiley Periodicals, Inc. Head Neck, 2011
Aluminum stress and its role in the phospholipid signaling pathway in plants and possible biotechnological applications
Authors: Poot‐Poot Wilberth , Teresa Hernandez‐Sotomayor Soledad M. 
Published: September 2011

AbstractAn early response of plants to environmental signals or abiotic stress suggests that the phospholipid signaling pathway plays a pivotal role in these mechanisms. The phospholipid signaling cascade is one of the main systems of cellular transduction and is related to other signal transduction mechanisms. These other mechanisms include the generation of second messengers and their interactions with various proteins, such as ion channels. This phospholipid signaling cascade is activated by changes in the environment, such as phosphate starvation, water, metals, saline stres, and plant–pathogen interactions. One important factor that impacts agricultural crops is metal‐induced stress. Because aluminum has been considered to be a major toxic factor for agriculture conducted in acidic soils, many researchers have focused on understanding the mechanisms of aluminum toxicity in plants. We have contributed the last fifteen years in this field by studying the effects of aluminum on phospholipid signaling in coffee, one of the Mexico's primary crops. We have focused our research on aluminum toxicity mechanisms in Coffea arabica suspension cells as a model for developing future contributions to the biotechnological transformation of coffee crops such that they can be made resistant to aluminum toxicity. We conclude that aluminum is able to not only generate a signal cascade in plants but also modulate other signal cascades generated by other types of stress in plants. The aim of this review is to discuss possible involvement of the phospholipid signaling pathway in the aluminum toxicity response of plant cells. © 2011 IUBMB IUBMB Life, 2011
CD43 regulates the threshold for T cell activation by targeting Cbl functions
Authors: Pedraza‐Alva Gustavo , Mérida Lilia B. , del Rio Roxana , Fierro Nora A. , Cruz‐Muñoz Mario E. , Olivares Norma , Melchy Erika , Igras Vivian , Holländer Georg A. , Burakoff Steven J. , Rosenstein Yvonne 
Published: September 2011

AbstractT cell (TC) activation requires the coordinated signaling of the T cell receptor (TCR) and coreceptor molecules, allowing TCs to respond to lower degrees of TCR occupancy. Coreceptor molecules set the threshold for TC activation by controlling different regulatory signaling loops. The Cbl family members prevent undesired activation of T cells by regulating TCR signals. In this report, we show that TC prestimulation by the CD43 coreceptor molecule before TCR engagement inhibits TCR‐dependent c‐Cbl tyrosine phosphorylation, c‐Cbl interaction with the adapter molecule Crk‐L and promotes Cbl‐b degradation in a PKCθ‐dependent manner. Consequently, the prolonged tyrosine phosphorylation and delayed degradation of ZAP‐70 and of the ζ chain lead to enhanced mitogen‐activated protein kinase activation and robust TC response. These data indicates that CD43‐mediated signals lower the threshold for TC activation by restricting the c‐Cbl and Cbl‐b inhibitory effects on TCR signaling. In addition to the strength and duration of intracellular signals, our data underscore temporality with which certain molecules are engaged as yet another mechanism to fine tune TC signal quality, and ultimately immune function. © 2011 IUBMB IUBMB Life, 2011
Signaling through Toll‐like receptor 4 and mast cell‐dependent innate immunity responses
Authors: Avila Martin , Gonzalez‐Espinosa Claudia 
Published: September 2011

AbstractSignal transduction through Toll‐like receptors (TLRs) has been one of the main topics in immunology research in recent years. Because of their signaling particularities based on the homotypic recognition of protein domains in multiple adaptors and selective activation of protein kinases, TLRs have become a paradigm to study ligand recognition coupled to dynamic and highly specific transcriptional and secretory responses in immune cells. Particularly, deleterious effects of Gram‐negative bacteria‐associated immune reactions has promoted intense research in the field, leading to the description of a number of canonical molecules connecting lipopolysaccharide‐induced TLR4 activation with NFκB‐dependent transcription. However, the diversity of immune cell phenotypes and the activity of distinct immune receptors in the same cell, strongly suggest that a number of elements in TLR4 signaling cascade, such as novel coreceptors, tyrosine kinases, and molecules regulating the secretion of preformed mediators remain to be described. Recent investigations have placed the mast cells, widely known by their role on allergic responses, as important effectors of innate immunity reactions against Gram‐negative bacteria. Their remarkable capacity of cytokine storage, synthesis and release, and the large number of inflammatory reactions controlled by their activation, suggest the existence of new modulators of TLR4 signaling in this particular cell type. © 2011 IUBMB IUBMB Life, 2011
mTORC1‐ and mTORC2‐interacting proteins keep their multifunctional partners focused
Authors: Bracho‐Valdés Ismael , Moreno‐Alvarez Paola , Valencia‐Martínez Israel , Robles‐Molina Evelyn , Chávez‐Vargas Lydia , Vázquez‐Prado José 
Published: September 2011

AbstractThe mammalian target of rapamycin, best known as mTOR, is a phylogenetically conserved serine/threonine kinase that controls life‐defining cellular processes such as growth, metabolism, survival, and migration under the influence of multiple interacting proteins. Historically, the cellular activities blocked by rapamycin in mammalian cells were considered the only events controlled by mTOR. However, this paradigm changed with the discovery of two signaling complexes differentially sensitive to rapamycin, whose catalytic component is mTOR. The one sensitive to rapamycin, known as mTORC1, promotes protein synthesis in response to growth factors and nutrients via the phosphorylation of p70S6K and 4EBP1; while the other, known as mTORC2, promotes cell migration and survival via the activation of Rho GTPases and the phosphorylation of AKT, respectively. Although mTORC2 kinase activity is not inhibited by rapamycin, hours of incubation with this antibiotic can impede the assembly of this signaling complex. The direct mechanism by which mTORC2 leads to cell migration depends on its interaction with P‐Rex1, a Rac‐specific guanine nucleotide exchange factor, while additional indirect pathways involve the intervention of PKC or AKT, multifunctional ubiquitous serine/threonine kinases that activate effectors of cell migration upon being phosphorylated by mTORC2 in response to chemotactic signals. These mTORC2 effectors are altered in metastatic cancer. Numerous clinical trials are testing mTOR inhibitors as potential antineoplasic drugs. Here, we briefly review the actions of mTOR with emphasis on the controlling role of mTORC1 and mTORC2‐interacting proteins and highlight the mechanisms linked to cell migration. © 2011 IUBMB IUBMB Life, 2011
Protein kinase C in Wnt signaling: Implications in cancer initiation and progression
Authors: Luna‐Ulloa Luis Bernardo , Hernández‐Maqueda José G. , Castañeda‐Patlán M. Cristina , Robles‐Flores Martha 
Published: September 2011

AbstractAlthough it is well known that Wnt and protein kinase C (PKC) signaling pathways are both involved in carcinogenesis and tumor progression, their synergistic contribution to these processes or the crosstalk between them has just recently been approached. The Wnt and PKC signaling are involved in many cellular functions including proliferation, differentiation, survival, apoptosis, cytoskeletal remodeling, and cell motility. Canonical Wnt signaling has been well characterized as one of the most important contributors to tumorigenesis, and it has been implicated in many types of solid tumors. PKC is one of the key targets of noncanonical Wnt signaling, particularly in the Wnt/Ca2+ pathway. Recently, data have implicated components of noncanonical Wnt/Ca2+ and Wnt/planar cell polarity signaling in directly promoting the invasiveness and malignant progression of diverse forms of human cancer. But, unlike the canonical pathway, defining the roles of noncanonical Wnt signaling in human cancer is in its infancy. In this review, we provide a concise description of the current knowledge of the interaction between PKC and Wnt pathways and discuss the role of this crosstalk in cancer initiation and progression. © 2011 IUBMB IUBMB Life, 2011
Blood thioredoxin reductase activity, oxidative stress and hematological parameters in painters and battery workers: relationship with lead and cadmium levels in blood
Authors: Conterato Greicy M. M. , Bulcão Rachel P. , Sobieski Rocheli , Moro Angela M. , Charão Mariele F. , de Freitas Fernando A. , de Almeida Fernanda L. , Moreira Ana P. L. , Roehrs Miguel , Tonello Raquel , Batista Bruno L. , Grotto Denise , Barbosa Fernando , Garcia Solange C. , Emanuelli Tatiana 
Published: September 2011

ABSTRACTOxidative stress has been shown to be involved in lead and cadmium toxicity. We recently showed that the activity of the antioxidant enzyme thioredoxin reductase (TrxR) is increased in the kidneys of lead‐exposed rats. The present study evaluated the blood cadmium and blood lead levels (BLLs) and their relationship with hematological and oxidative stress parameters, including blood TrxR activity in 50 painters, 23 battery workers and 36 control subjects. Erythrocyte δ‐aminolevulinate dehydratase (δ‐ALA‐D) activity and its reactivation index were measured as biomarkers of lead effects. BLLs increased in painters, but were even higher in the battery workers group. In turn, blood cadmium levels increased only in the painters group, whose levels were higher than the recommended limit. δ‐ALA‐D activity was inhibited only in battery workers, whereas the δ‐ALA‐D reactivation index increased in both exposed groups; both parameters were correlated to BLLs (r = −0.59 and 0.84, P < 0.05), whereas the reactivation index was also correlated to blood cadmium levels (r = 0.27, P < 0.05). The changes in oxidative stress and hematological parameters were distinctively associated with either BLLs or blood cadmium levels, except glutathione‐S‐transferase activity, which was correlated with both lead (r = 0.34) and cadmium (r = 0.47; P < 0.05). However, TrxR activity did not correlate with any of the metals evaluated. In conclusion, blood TrxR activity does not seem to be a good parameter to evaluate oxidative stress in lead‐ and cadmium‐exposed populations. However, lead‐associated changes in biochemical and hematological parameters at low BLLs underlie the necessity of re‐evaluating the recommended health‐based limits in occupational exposure to this metal. Copyright © 2011 John Wiley & Sons, Ltd.
Deoxyactein stimulates osteoblast function and inhibits bone‐resorbing mediators in MC3T3‐E1 cells
Authors: Choi Eun Mi 
Published: September 2011

ABSTRACTOsteoporosis is a systemic skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue, with a consequent increase in bone fragility and susceptibility to fracture. In order to improve the treatment of osteoporosis, identification of anabolic agents with minimal side effects is highly desirable. Cimicifuga racemosa has a long and diverse history of medicinal use and deoxyactein isolated from this species is one of the major constituents. In the present study, the effect of deoxyactein on the function of osteoblastic MC3T3‐E1 cells was studied. Deoxyactein caused a significant elevation of cell growth, alkaline phosphatase activity, collagen content, and mineralization in the cells (P < 0.05). Moreover, deoxyactein significantly (P < 0.05) decreased the production of reactive oxygen species (ROS) and osteoclast differentiation‐inducing factors such as TNF‐α, IL‐6 and receptor activator of nuclear factor‐κB ligand in the presence of antimycin A, which inhibits mitochondrial electron transport and has been used as an ROS generator. These results demonstrate that deoxyactein may have positive effects on skeletal structure. Copyright © 2011 John Wiley & Sons, Ltd.
Local protein backbone folds determined by calculated NMR chemical shifts
Authors: Czajlik András , Hudáky Ilona , Perczel András 
Published: September 2011

AbstractNMR chemical shifts (CSs: δNNH, δCα, δCβ, δC′, δHNH, and δHα) were computed for the amino acid backbone conformers (αL, βL, γL, δL, εL, αD, γD, δD, and εD [Perczel et al., J Am Chem Soc 1991, 113, 6256]) modeled by oligoalanine structures. Topological differences of the extended fold were investigated on single β‐strands, hairpins with type I and II β‐turns, as well as double‐ and triple‐stranded β‐sheet models. The so‐called “capping effect” was analyzed: residues at the termini of a homoconformer sequence unit usually have different CSs than the central residues of an adequately long homoconformer model. In heteroconformer sequences capping effect ruins the direct applicability of several chemical shift types (δHNH, δC′, and δNNH) for backbone structure determination of the parent residue. Experimental δHα, δCα, and δCβ values retrieved from protein database are in good agreement with the relevant computed data in the case of the common backbone conformers (αL, βL, γL, and εL), even though neighboring residue effects were not accounted for. Experimental and computed ΔδHα‐ΔδCα, ΔδHα‐ΔδCβ, and ΔδCα‐ΔδCβ maps give qualitatively the same picture, that is, the positions of the backbone conformers relative to each other are very similar. This indicates that the Hα, Cα, and Cβ chemical shifts of alanine depend considerably on the backbone fold of the parent residue also in proteins. We provide tabulated CSs of the chiral amino acids that may predict the various structures of the residues. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
A Novel Polymeric Chemosensor: Dual Colorimetric Detection of Metal Ions Through Click Synthesis
Authors: Li Yongrong , Ashizawa Minoru , Uchida Satoshi , Michinobu Tsuyoshi 
Published: September 2011

AbstractA highly colored polystyrene derivative bearing side chain chromophores composed of dialkylanilino donor and cyano‐based acceptor groups, prepared by atom‐economic click postfunctionalization, displays the dual colorimetric detection behavior of several metal ions based on the specific interactions with different nitrogen atoms. Hard to borderline metal ions, such as Fe3+, Fe2+, and Sn2+, are always recognized by the dialkylanilino nitrogen atom, resulting in a decrease in the charge‐transfer (CT) band intensity of the donor–acceptor chromophores. On the other hand, the recognition site of a soft metal ion of Ag+ is the cyano nitrogen atom due to the readily formed multivalent coordination, which produces a bathochromic shift of the CT band.