bluuebunny/crossref_metadata_2025_split huggingface dataset:
Strain rate and temperature dependence of a nanoparticle‐filled poly(dimethylsiloxane) undergoing shear deformation
Authors: Yan Lei , Dillard David A. , West Robert L. , Rubis Kenneth J. , Gordon Glenn V. 
Published: May 2012

AbstractThe mechanical properties in shear of unfilled and nanoparticle‐filled polydimethylsiloxane (PDMS) networks are reported. The effect of silicate‐based nanoparticles on the mechanical response was studied as functions of rate and temperature using the time–temperature superposition principle. An apparent yielding phenomenon was observed in the filled polymer in spite of the more typical elastomeric behavior exhibited by the pure PDMS network. The time–temperature superposition principle was applied to capture the shear strain rate (10−4–10−1 s−1) and temperature (−40 to 60°C) dependence of the stress response of the filled PDMS at different strains and at the yield point. A power‐law relationship was found to adequately describe the resulting master curves for yield stress in shear. Using a triangular shear displacement profile at 10−2 s−1, the effect of temperature (−20 to 80°C) on the recovery from a particularly pronounced Mullins effect was investigated as a function of rest time. Given adequate rest time (between 10 and 102 min), recovery was observed for the temperature range studied. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
N‐terminal acetylation of α‐synuclein induces increased transient helical propensity and decreased aggregation rates in the intrinsically disordered monomer
Authors: Kang Lijuan , Moriarty Gina M. , Woods Lucy A. , Ashcroft Alison E. , Radford Sheena E. , Baum Jean 
Published: May 2012

AbstractThe conformational properties of soluble α‐synuclein, the primary protein found in patients with Parkinson's disease, are thought to play a key role in the structural transition to amyloid fibrils. In this work, we report that recombinant 100% N‐terminal acetylated α‐synuclein purified under mild physiological conditions presents as a primarily monomeric protein, and that the N‐terminal acetyl group affects the transient secondary structure and fibril assembly rates of the protein. Residue‐specific NMR chemical shift analysis indicates substantial increase in transient helical propensity in the first 9 N‐terminal residues, as well as smaller long‐range changes in residues 28–31, 43–46, and 50–66: regions in which the three familial mutations currently known to be causative of early onset disease are found. In addition, we show that the N‐terminal acetylated protein forms fibrils that are morphologically similar to those formed from nonacetylated α‐synuclein, but that their growth rates are slower. Our results highlight that N‐terminal acetylation does not form significant numbers of dimers, tetramers, or higher molecular weight species, but does alter the conformational distributions of monomeric α‐synuclein species in regions known to be important in metal binding, in association with membranes, and in regions known to affect fibril formation rates.
How cells process information: Quantification of spatiotemporal signaling dynamics
Authors: Ganesan Ambhighainath , Zhang Jin 
Published: May 2012

AbstractArguably, one of the foremost distinctions between life and non‐living matter is the ability to sense environmental changes and respond appropriately—an ability that is invested in every living cell. Within a single cell, this function is largely carried out by networks of signaling molecules. However, the details of how signaling networks help cells make complicated decisions are still not clear. For instance, how do cells read graded, analog stress signals but convert them into digital live‐or‐die responses? The answer to such questions may originate from the fact that signaling molecules are not static but dynamic entities, changing in numbers and activity over time and space. In the past two decades, researchers have been able to experimentally monitor signaling dynamics and use mathematical techniques to quantify and abstract general principles of how cells process information. In this review, the authors first introduce and discuss various experimental and computational methodologies that have been used to study signaling dynamics. The authors then discuss the different types of temporal dynamics such as oscillations and bistability that can be exhibited by signaling systems and highlight studies that have investigated such dynamics in physiological settings. Finally, the authors illustrate the role of spatial compartmentalization in regulating cellular responses with examples of second‐messenger signaling in cardiac myocytes.
Open quantum dots: Physics of the non‐Hermitian Hamiltonian
Authors: Ferry D.K. , Akis R. , Burke A.M. , Knezevic I. , Brunner R. , Bird J.P. , Meisels R. , Kuchar F. , Bird J.P. 
Published: May 2012

AbstractQuantum dots provide a natural system in which to study both classical and quantum features of transport, as they possess a very rich set of eigenstates.When coupled to the environment through a pair of quantum point contacts, these dots possess a mixed phase space which yields families of closed, regular orbits as well as an expansive sea of chaos. In this latter case, many of the eigenstates are decohered through interaction with the environment, but many survive and are referred to as the set of pointer states. These latter states are described by a projected, non‐Hermitian Hamiltonian which describes their dissipation through many‐body interactions with particles in the external environment.
Contact‐free reactions between micropipes in bulk SiC growth
Authors: Gutkin Mikhail Yu. , Sheinerman Alexander G. , Kohn Victor G. , Argunova Tatiana S. , Smirnov Mikhail A. , Je Jung Ho 
Published: May 2012

AbstractIt has been generally accepted that any reaction between micropipes in silicon carbide (SiC) crystals requires a direct contact of the micropipes. We propose a new model of contact‐free reactions that are realized through the emission and absorption of full‐core dislocations by micropipes.This model can explain the correlated reduction in micropipe radii in the samples with low micropipe densities which has been observed in synchrotron radiation (SR) phase contrast images supported by computer simulations. We provide a theoretical description of a contact‐free reaction between two parallel micropipes.
Linear response function approach for the boundary problem of QM/MM methods
Authors: Ueda Koki , Yamanaka Shusuke , Nakata Kazuto , Ehara Masahiro , Okumura Mitsutaka , Yamaguchi Kizashi , Nakamura Haruki 
Published: May 2012

AbstractWe present a simple approach to treat the boundary problem in quantum mechanics and molecular mechanical (QM/MM) methods. The method is based on ab initio calculations of linear response functions, which indicate nonlocal polarization of densities due to the perturbations at the specific site. We describe basic ideas as well as some numerical results. The computational results will be discussed with the boundary problem in QM/MM methods. © 2012 Wiley Periodicals, Inc.
Semiquantal molecular dynamics simulations of hydrogen‐bond dynamics in liquid water using spherical gaussian wave packets
Authors: Ono Junichi , Hyeon‐Deuk Kim , Ando Koji 
Published: May 2012

AbstractA semiquantal (SQ) molecular dynamics (MD) simulation method using spherical Gaussian wave packets (WPs) is applied to a microscopic analysis of hydrogen‐bond (H‐bond) exchange dynamics in liquid water. We focus on the molecular jump mechanism of H‐bond reorientation dynamics proposed from a classical MD simulation by Laage and Hynes (Science 2006, 311, 832). As a notable quantum effect, broadenings of both the oxygen and hydrogen WPs of jumping water are observed associated with the H‐bond switching events. Nonetheless, quantum effects on averaged trajectories of structural parameters measured with respect to the WP centers are rather minor. A 1/f fluctuation of local H‐bond number is observed in both SQ and classical simulations. This is obtained straightforwardly from the real‐time trajectories, in contrast with the originally found 1/f fluctuation (Sasai et al., J. Chem. Phys. 1992, 96, 3045) of the total potential energies collected at quenched inherent structures. The quantum effects are found to accelerate the relaxation of H‐bond number fluctuation, which is reflected in the region near the lower bound of the 1/f behavior in the power spectra. New developments in the implementation of SQMD simulations including all atoms are also described. © 2012 Wiley Periodicals, Inc.
Some formal properties of ensemble density functionals
Authors: Joubert Daniel P. 
Published: May 2012

AbstractFormal properties of ensemble density functionals are examined. Expressions for the difference between energy functionals where the particle number differs by one are constructed in terms of their first functional derivatives for the universal energy functional, the electron–electron repulsion energy functional, and the interacting kinetic energy functional. Equations that must be satisfied by second and higher order functional derivatives are derived. It is also shown that the shape of
${\delta V_{ee}[\rho]\over\delta\rho({\bf r})}$
and ${\delta K[\rho]\over\delta\rho({\bf r})}$, the functional derivatives of the mutual electron–electron repulsion, and kinetic energy, respectively, are separately particle number independent for particle numbers between successive integers. © 2013 Wiley Periodicals, Inc.
Disturbance‐driven model predictive control by means of Youla–Kučera parameter switching with an application to drainage canal control
Authors: Blanchini Franco , Pellegrino Felice Andrea , Miani Stefano 
Published: May 2012

SUMMARYMotivated by applications such as drainage canal control, where the disturbance acting on a system can be predicted on the basis of weather forecast, we propose a model predictive control technique consisting in the online tuning of a Youla–Kučera parameter. Essentially, the optimal control sequence is supplied to the system by properly setting the coefficients of the Youla–Kučera parameter taken as a finite impulse response, whose length depends on that of the optimal trajectory. Stability is guaranteed for any arbitrary choice of the time‐varying coefficients that are adapted to the current forecast of disturbance. The approach is illustrated by numerical simulations of a drainage canal control system. Copyright © 2012 John Wiley & Sons, Ltd.
Mediation Effects of Environmental Cooperation on the Relationship between Sustainable Design and Performance Improvement among Chinese Apartment Developers
Authors: Zhu Qinghua , Zhao Tielin , Geng Yong 
Published: May 2012

ABSTRACTDue to increasing pressure for energy saving and emission reduction, Chinese apartment developers have initiated sustainable design practices. This paper develops a conceptual model which proposes that cooperation with construction stakeholders and customers is a mediator, necessary for apartment developers to realize environmental, economic and even competitive performance improvement through sustainable design practices. The paper examines the current practice situations of sustainable design, cooperation with construction stakeholders and customers as well as related performance improvement among Chinese apartment developers based on 92 questionnaires conducted by the authors. The mediation effects are further analysed through hierarchical regression analysis. Statistical results indicate that sustainable design should be further promoted by the Chinese governments and implemented by Chinese apartment developers. Policy implications are discussed to provide detailed suggestions on improving the cooperation with Chinese apartment developers and their construction stakeholders/customers. Such cooperation can help apartment developers to improve environmental, competitive and economic performance through sustainable design practices. Copyright © 2012 John Wiley & Sons, Ltd and ERP Environment.
A generic static analyzer for multithreaded Java programs
Authors: Ferrara P. 
Published: May 2012

SUMMARYIn this paper, we present heckmate, the first generic static analyzer of multithreaded Java programs based on abstract interpretation. heckmate can be tuned at different levels of precision and efficiency in order to prove various properties (e.g., absence of divisions by zero and data races), and it is sound for multithreaded programs. It supports all the most relevant features of Java multithreading, such as dynamic thread creation, runtime creation of monitors, and dynamic allocation of memory. The experimental results demonstrate that heckmate is accurate and efficient enough to analyze programs with some thousands of statements and a potentially infinite number of threads. Copyright © 2012 John Wiley & Sons, Ltd.
An unequal clustering algorithm based on energy balance for wireless sensor networks
Authors: Xu Guangwei , Zhu Ming , Luo Xin , Wu Min , Ren Fuji 
Published: May 2012

AbstractSensor nodes in sensor networks often gather data and deliver them to the sink. However, the energy and radio range constraints force them to cooperate in transmitting the data to the destination with multihop communication. To achieve this, nodes have to be clustered and some of them are elected as the cluster head nodes to transmit the aggregated data. Unfortunately, the clustering brings extra traffic load to the cluster head nodes, particularly those closer to the sink. These nodes die faster than before as their energy is drained at a high rate. Therefore, some clustering and cluster head election algorithms were suggested to use the unequal clustering size to extend the lifetime of cluster head nodes. However, it is difficult to obtain the accurate cluster size in the process of unequal clustering. Moreover, some cluster head nodes with the overfull cluster members may die early. We propose an enhanced unequal clustering size algorithm to optimize the unequal cluster size in the different layers and balance the dissipation energy of all cluster head nodes. Simulation results show that our algorithm dissipates approximately the same energy of cluster head nodes in the different layers per round and obviously increases the number of rounds of data gathering and transmission. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Serotonin signaling in eating disorders
Authors: Compan Valérie , Laurent Laetitia , Jean Alexandra , Macary Céline , Bockaert Joël , Dumuis Aline 
Published: May 2012

AbstractThe brain serotonin (5‐hydroxytryptamine, 5‐HT) system is implicated in the neurobiological control of feeding and appears to be dysfunctional in patients suffering from feeding disorders, such as anorexia, bulimia, and obesity. Thanks to the identification and cloning of 5‐HT receptors, the production of agonist and antagonist compounds, and the generation of 5‐HT receptor knock‐out mice, our knowledge on the implication of different 5‐HT receptor subtypes in feeding behavior has greatly increased. A number of studies have demonstrated an involvement of the hypothalamic 5‐HT1B and 5‐HT2C receptors in food intake and body weight control, but the downstream events induced by such signaling remain to be explored. Moreover, little is known about the influence of 5‐HT on the rewarding value of eating. Such value may not necessarily be linked to food consumption, but rather to voluntary reduction of food intake, as recently demonstrated upon activation of the 5‐HT4 receptors in the nucleus accumbens. Thus, abnormalities in the reward system in addition to those in the central control of the autonomic nervous system might contribute to the anorexic behavior. Recent studies have also reported an involvement of the 5‐HT6 and 5‐HT7 receptors in feeding behavior. Potential 5‐HT receptor agonists/antagonists could then be developed and used in association with psychological treatment to better cope with the stressors that trigger anorexia and drug dependence. WIREs Membr Transp Signal 2012, 1:715–729. doi: 10.1002/wmts.45For further resources related to this article, please visit the WIREs website.
Serotonergic signaling: multiple effectors and pleiotropic effects
Authors: Masson Justine , Emerit Michel Boris , Hamon Michel , Darmon Michèle 
Published: May 2012

AbstractSerotonin (5‐HT) is a neurotransmitter which exerts both central and peripheral control on numerous physiological functions such as sleep/wake cycle, thermoregulation, food intake, nociception, locomotion, sexual behavior, gastrointestinal motility, blood coagulation, and cardiovascular homeostasis. These multiple effects are mediated by a family of serotonin receptors which comprises at least 13 distinct G‐protein‐coupled receptors (GPCRs) of the A type and a combination of ligand‐gated cation channel heteropentameric receptors of the conserved 5‐HT3 Cys‐loop type. Many of these receptors are targets of pharmaceutical drugs justifying the wide interest to elucidate their functioning. Over the past decades, substantial investigations have led to the current understanding of the complex signal transduction mechanisms which these receptors initiate. The idea of a unique coupling of a receptor to a linear pathway has evolved into a multiplicity of alternative bifurcations and feedback mechanisms. The emerging signaling model includes the capacity of 5‐HT receptors GPCR superfamily to couple and initiate transduction through several G proteins depending on the tissue and/or the presence of interacting proteins. In turn, these G proteins may activate many effectors. On the other hand, the complexity increases further with the capacity of 5‐HT receptors to transduce signals through G‐protein‐independent pathways. These multiple couplings often participate in the control of gene transcription, thereby resulting in 5‐HT‐mediated long‐term (neuroplastic) adaptive functional changes. WIREs Membr Transp Signal 2012, 1:685–713. doi: 10.1002/wmts.50For further resources related to this article, please visit the WIREs website.
Transport of water against its concentration gradient: fact or fiction?
Authors: Zeuthen Thomas , MacAulay Nanna 
Published: May 2012

AbstractWater transport across cell membranes is central to most physiological functions. About 200 L of water move across epithelial cells each day in humans in order to maintain whole‐body homeostasis; water transport in and out of organs such as the brain and eye are of major clinical importance. It is well established that the water transport is driven by ion transport, but how? Osmosis is not always the answer: water can be transported against considerable osmotic gradients, apparently without any external osmotic or hydrostatic driving forces.It is generally accepted that cotransporters of the symport type play a key role for the coupling between ion and water fluxes. Models of coupling are either molecular or based on unstirred layer effects, and can be distinguished by their response time: for molecular models, water transport follows changes of substrate transport instantaneously; in unstirred layer models there is a delay while the osmolarity changes in the solutions surrounding the cotransport protein. For cotransporters expressed heterologously in Xenopus oocytes, influx of water can be detected about 1 second after initiation of cotransport of ions and other substrates. This is 20 times faster than expected (and observed) for unstirred layer effects. Water transport in cotransporters is best explained by a molecular model in which ion and water fluxes are coupled by a mechanism within the protein. This would also clarify how cotransporters exploit the free energy in the ion fluxes for the uphill transport of water. WIREs Membr Transp Signal 2012, 1:373–381. doi: 10.1002/wmts.54For further resources related to this article, please visit the WIREs website.
Synthesis, Characterization, and Properties of a Carbonate‐Bridged Dinuclear Rhodium(III) Complex via Fixation of Atmospheric CO2
Authors: Du Liyong , Zhang Songlin , Ding Yuqiang 
Published: May 2012

AbstractA carbonate‐bridged rhodium(III) dimeric complex of formula μ‐CO3‐[(ppy)2Rh]2, (ppy = 2‐phenylpyridine) was synthesized and characterized by IR and 1H NMR spectroscopy as well as X‐ray diffraction. The bridging carbonate ion presumably originates from the capture of CO2 in air deduced on a series of control experiments, which may have valuable implications for the study of fixation of CO2. The luminescent and thermal properties of this complex were also investigated.
Cationic η6‐Coordinated BINAP Rhodium Complexes with Benzene and Toluene
Authors: Fischer Christian , Selle Carmen , Drexler Hans‐Joachim , Heller Detlef 
Published: May 2012

AbstractTwo novel BINAP rhodium complexes containing η6‐coordinated arenes have been disclosed. Both have been characterized by X‐ray analysis and NMR spectroscopy.
Paradox of marine protected areas: suppression of fishing may cause species loss
Authors: Takashina Nao , Mougi Akihiko , Iwasa Yoh 
Published: May 2012

AbstractA number of fish and invertebrate stocks have been depleted by overexploitation in recent years. To address this, marine protected areas (MPAs) are often established to protect biodiversity and recover stocks. We analyzed the potential impact of establishing MPAs on marine ecosystems using mathematical models. We demonstrate that establishment of an MPA can sometimes result in a considerable decline, or even extinction, of a species. We focus on a prey–predator system in two patches, one exposed to fishing activity and the other protected (MPA). Our analyses reveal that the establishment of the MPA can cause a reduction in prey abundance, and even extinction of the prey. Such unintended consequences are more likely to occur if the predator species is a generalist and if the MPA is intended to protect only the predatory species. Further, a mobile predator that migrates adaptively rather than randomly is associated with a greater reduction in prey abundance.
The Intelligent Egg, and How It Got That Way: from Genes to Genius in a Few Easy Lessons
Authors: Weiss Kenneth M. 
Published: May 2012

Abstract
A seed has no flowers or leaves, and an egg no fingers or lungs. Yet plants and animals not only have these things but they resemble their parents in detail throughout their bodies. Something is inherited, but what is it? Life is based on the activities of cells. An organism has large numbers of them—a human has trillions! Cells live as separate units, which enables them each to do its own thing within its particular organ, but to be an organism they must work together. A cell can only detect its immediate local environment, but that includes various kinds of signals or information from nearby or far away within the body—or even from the external environment. It is by being local but responding globally in this way that an egg becomes an organism, an organism manages its way through life, and organisms make up species and ecosystems that interact with each other. The evolution of these abilities has produced the glorious array of living forms that populate the world. In these ways, an egg may have no thoughts but is a highly intelligent being.