bluuebunny/crossref_metadata_2025 huggingface dataset:
Expression, subunit composition, and function of AMPA‐type glutamate receptors are changed in activated microglia; possible contribution of GluA2 (GluR‐B)‐deficiency under pathological conditions
Authors: Beppu Kaoru , Kosai Yuki , Kido Mizuho A. , Akimoto Nozomi , Mori Yuki , Kojima Yuichiro , Fujita Kyota , Okuno Yuko , Yamakawa Yukiko , Ifuku Masataka , Shinagawa Rika , Nabekura Junichi , Sprengel Rolf , Noda Mami
Published: March 2013

Microglia express AMPA (α‐amino‐hydroxy‐5‐methyl‐isoxazole‐4‐propionate)‐type of glutamate (Glu) receptors (AMPAR), which are highly Ca2+ impermeable due to the expression of GluA2. However, the functional importance of AMPAR in microglia remains to be investigated, especially under pathological conditions. As low expression of GluA2 was reported in some neurodegenerative diseases, GluA2−/− mice were used to show the functional change of microglial AMPARs in response to Glu or kainate (KA). Here we found that Glu‐induced currents in the presence of 100 μM cyclothiazide, an inhibitor of AMPAR desensitization, showed time‐dependent decrease after activation of microglia with lipopolysaccharide (LPS) in GluA2+/+ microglia, but not in GluA2−/− microglia. Upon activation of microglia, expression level of GluA2 subunits significantly increased, while expression of GluA1, A3 and A4 subunits on membrane surface significantly decreased. These results suggest that nearly homomeric GluA2 subunits were the main reason for low conductance of AMPAR in activated microglia. Increased expression of GluA2 in microglia was also detected partially in brain slices from LPS‐injected mice. Cultured microglia from GluA2−/− mice showed higher Ca2+‐permeability, consequently inducing significant increase in the release of proinflammatory cytokine, such as TNF‐α. The conditioning medium from KA‐treated GluA2−/− microglia had more neurotoxic effect on wild type cultured neurons than that from KA‐treated GluA2+/+ microglia. These results suggest that membrane translocation of GluA2‐containing AMPARs in activated microglia has functional importance and thus, dysfunction or decreased expression of GluA2 may accelerate Glu neurotoxicity via excess release of proinflammatory cytokines from microglia.
Monitoring deformation at the Geysers Geothermal Field, California using C‐band and X‐band interferometric synthetic aperture radar
Authors: Vasco D. W. , Rutqvist Jonny , Ferretti Alessandro , Rucci Alessio , Bellotti Fernando , Dobson Patrick , Oldenburg Curtis , Garcia Julio , Walters Mark , Hartline Craig
Published: March 2013

We resolve deformation at The Geysers Geothermal Field using two distinct sets of interferometric synthetic aperture radar (InSAR) data. The first set of observations utilize archived European Space Agency C‐band synthetic aperture radar data from 1992 through 1999 to image the long‐term and large‐scale subsidence at The Geysers. The peak range velocity of approximately 50 mm/year agrees with previous estimates from leveling and global positioning system observations. Data from a second set of measurements, acquired by TerraSAR‐X satellites, extend from May 2011 until April 2012 and overlap the C‐band data spatially but not temporally. These X‐band data, analyzed using a combined permanent and distributed scatterer algorithm, provide a higher density of scatterers (1122 per square kilometer) than do the C‐band data (12 per square kilometer). The TerraSAR‐X observations resolve 1 to 2 cm of deformation due to water injection into a Northwest Geysers enhanced geothermal system well, initiated on October 2011. The temporal variation of the deformation is compatible with estimates from coupled numerical modeling.
Throughfall and stemflow vary seasonally in different land‐use types in a lower montane tropical region of Panama
Authors: Macinnis‐Ng Catriona M.O. , Flores Eric E. , Müller Henry , Schwendenmann Luitgard
Published: March 2013

Catchment hydrology is influenced by land‐use change through alteration of rainfall partitioning processes. We compared rainfall partitioning (throughfall, stemflow and interception) and soil water content in three land‐use types (primary forest, secondary forest and agriculture) in the Santa Fe region of Panama. Seasonal patterns were typified by larger volumes of throughfall and stemflow in the wet season, and the size of precipitation events was the main driver of variation in rainfall redistribution. Land‐use‐related differences in rainfall partitioning were difficult to identify due to the high variability of throughfall. However, annual throughfall in agricultural sites made up a larger proportion of gross precipitation than throughfall in forest sites (94 ± 1, 83 ± 6 and 81 ± 1% for agriculture, primary and secondary forests, respectively). Proportional throughfall (% of gross precipitation becoming throughfall) was consistent throughout the year for primary forest, but for secondary forest, it was larger in the dry season than the wet season. Furthermore, proportional stemflow in the dry season was larger in secondary forest than primary forest. Stemflow, measured only in primary and secondary forests, ranged between 0.9 and 3.2% of gross precipitation. Relative soil moisture content in agricultural plots was generally elevated during the first half of the dry season in comparison to primary and secondary forests. Because throughfall is elevated in agricultural plots, we suggest careful management of the spatial distribution and spread of this land‐use type to mitigate potential negative impacts in the form of floods and high erosion rates in the catchment. Copyright © 2013 John Wiley & Sons, Ltd.
Regional differences in hydrological response to canopy interception schemes in a land surface model
Authors: Zhang Chi , Wang Dagang , Wang Guiling , Yang Weitao , Liu Xiaoping
Published: March 2013

Two different canopy interception schemes are applied to the parameterization of the hydrological processes in the Community Land Model version 3. One scheme treats rainfall and canopy water storage as spatially uniform within each model grid cell, and the other scheme considers sub‐grid variability of rainfall and water storage in the parameterization of canopy hydrological processes. The hydrological responses to differences between these two schemes in different regions are studied. It is found that the impact of the sub‐grid variability in the tropical regions is generally greater than the extra‐tropical regions. However, such impact can't be negligible for the extra‐tropical regions. Soil water in the total 3.4 m soil depth increases by 3% for Central‐South Europe, and vegetation temperature increases by 0.14 °C for Southeastern United States if the regional averages are considered. The magnitude of the impact is greater if the analysis focuses on the specific grid cells in these regions. The impact is tightly correlated with rainfall amount and vegetation density. The correlation coefficient between such impact and rainfall amount and vegetation density varies with regions and hydrological variables, with the largest value of 0.92 for interception loss in Amazonia. Our results indicate that the impact of the sub‐grid variability on hydrological processes in the extra‐tropical areas is also important, although rainfall amount and vegetation density in these areas are not as high as in the tropical areas. Copyright © 2013 John Wiley & Sons, Ltd.
Long‐term variations and temporal scaling of hydroclimatic time series with focus on the German part of the Elbe River Basin
Authors: Markovic D. , Koch M.
Published: March 2013

Long‐term variations and temporal scaling of mean monthly time series of river flow, precipitation, temperature, relative humidity, air pressure, duration of bright sunshine, degree of cloud cover, short wave radiation, wind speed and potential evaporation within or in vicinity of the German part of the Elbe River Basin are analyzed. Statistically significant correlations between the 2–15 year scale‐averaged wavelet spectra of the hydroclimatic variables and the North Atlantic Oscillation‐ and Arctic Oscillation index are found which suggests that such long‐term patterns in hydroclimatic time series are externally forced. The Hurst parameter estimates (H) based on the Detrended Fluctuation Analysis (DFA) indicate persistence for discharge, precipitation, wind speed, air pressure and the degree of cloud cover, all having an annual cycle and a broad low‐frequency distribution. Also, DFA H parameter estimates are higher for discharge than for precipitation. The major long‐term quasi‐periodic variability modes of precipitation detected using Singular Spectrum Analysis coincide with those detected in the discharge time series. Upon subtraction of these low‐frequency quasi‐periodic modes, the DFA H parameter estimates suggest absence of the persistence for both precipitation and discharge. Copyright © 2013 John Wiley & Sons, Ltd.
Fear‐learning deficits in subjects with fibromyalgia syndrome?
Authors: Jenewein J. , Moergeli H. , Sprott H. , Honegger D. , Brunner L. , Ettlin D. , Grillon C. , Bloch K. , Brügger M. , Schwegler K. , Schumacher S. , Hasler G.
Published: March 2013

Background

Fibromyalgia syndrome (FMS) is frequently associated with psychiatric conditions, particularly anxiety. Deficits in contingency learning during fear conditioning have been hypothesized to increase anxiety and, consequently, pain sensation in susceptible individuals. The goal of this study was to examine the relationship between contingency learning and pain experience in subjects with FMS and rheumatoid arthritis (RA).

Methods

Fourteen female FMS subjects, 14 age‐matched female RA subjects and 14 age‐matched female healthy controls (HCs) were included in a fear‐conditioning experiment. The conditioned stimulus (CS) consisted of visual signs, the unconditioned stimulus (US) of thermal stimuli. CS− predicted low‐temperature exposure (US), while CS+ was followed by low or high temperature.

Results

In the FMS group, only 50% of the subjects were aware of the US–CS contingency, whereas 86% of the RA subjects and all of the HCs were aware of the contingency. CS+ induced more anxiety than CS− in RA subjects and HCs. As expected, low‐temperature exposure was experienced as less painful after CS− than after CS+ in these subjects. FMS subjects did not show such adaptive conditioning. The effects of the type of CS on heart rate changes were significant in the HCs and the aware FMS subjects, but not in the unaware FMS subjects.

Conclusions

Contingency learning deficits represent a potentially promising and specific, but largely unstudied, psychopathological factor in FMS. Deficits in contingency learning may increase anxiety and, consequently, pain sensation. These findings have the potential to contribute to the development of novel therapeutic approaches for FMS.
The effects of entrained debris on the basal sliding stability of a glacier
Authors: Zoet L. K. , Carpenter B. , Scuderi M. , Alley R. B. , Anandakrishnan S. , Marone C. , Jackson M.
Published: March 2013

New laboratory experiments exploring likely subglacial conditions reveal controls on the transition between stable sliding and stick‐slip motion of debris‐laden ice over rock, with implications for glacier behavior. Friction between a rock substrate and clasts in ice generates heat, which melts nearby ice to produce lubricating water. An increase in sliding speed or an increase in entrained debris raises heat generation and thus meltwater production. Unstable sliding is favored by low initial lubrication followed by rapid meltwater production in response to a velocity increase. Low initial lubrication can result from cold or drained conditions, whereas rapid increase in meltwater generation results from strong frictional heating caused by high sliding velocity or high debris loads. Strengthening of the interface (healing) during “stick” intervals between slip events occurs primarily through meltwater refreezing. When healing and unstable sliding are taken together, the experiments reported here suggest that stick‐slip behavior is common from motion of debris‐laden glacier ice over bedrock.
SERS investigation on the adsorption and photoreaction of 4‐nitroanisole in Ag hydrosols
Authors: Muniz‐Miranda Maurizio
Published: March 2013

The adsorption of 4‐nitroanisole on silver colloidal nanoparticles was investigated by surface‐enhanced Raman spectroscopy (SERS). Actually, the chemical binding with a metal substrate may play a role in changing the electronic structure of this molecule, which can be considered a push–pull chromophore, because an internal charge‐transfer occurs between methoxy and nitrogroup. A SERS signal could be detected only in chloride‐activated silver colloids, but the spectrum recorded with green‐light excitation was not related to adsorbed 4‐nitroanisole, but to its azoderivative, formed by photoreduction of the nitrogroup on the surface of the silver substrate. Copyright © 2013 John Wiley & Sons, Ltd.
Achieving landscape‐scale deer management for biodiversity conservation: The need to consider sources and sinks
Authors: Wäber Kristin , Spencer Jonathan , Dolman Paul M.
Published: March 2013

Hyper‐herbivory following predator removal is a global issue. Across North America and Europe, increasing deer numbers are affecting biodiversity and human epidemiology, but effectiveness of deer management in heterogeneous landscapes remains poorly understood. In forest habitats in Europe, deer numbers are rarely assessed and management is mainly based on impacts. Even where managed areas achieve stable or improving impact levels, the extent to which they act as sinks or persist as sources exporting deer to the wider landscape remains unknown. We present a framework to quantify effectiveness of deer management at the landscape scale. Applied across 234 km2of Eastern England, we assessed management of invasive Reeve's muntjac (Muntiacus reevesi) and native roe (Capreolus capreolus), measuring deer density (using thermal imaging distance transects 780 km/year), fertility, neonatal survival, and culling to quantify source‐sink dynamics over 2008–2010. Despite management that removed 23–40% of the annual population, 1,287 (95% CI: 289–2,680) muntjac and 585 (454–1,533) roe deer dispersed annually into the wider landscape, consistent with their ongoing range expansion. For roe deer, culled individuals comprised fewer young deer than predicted by a Leslie matrix model assuming a closed population, consistent with age‐dependent emigration. In this landscape, for roe and muntjac, an annual cull of at least 60% and 53%, respectively, is required to offset annual production. Failure to quantify deer numbers and productivity has allowed high density populations to persist as regional sources contributing to range expansion, despite deliberative management programs, and without recognition by managers who considered numbers and impacts to be stable. Reversing an unfavorable condition of woodland biodiversity requires appropriate culls across large contiguous areas, supported by knowledge of deer numbers and fertility. © 2013 The Wildlife Society.
Quasi phase matching in femtosecond pulse volume structured x‐cut lithium niobate
Authors: Thomas Jens , Hilbert Vinzenz , Geiss Reinhard , Pertsch Thomas , Tünnermann Andreas , Nolte Stefan
Published: March 2013

All optical inscription of quasi phase matching structures in an x‐cut LiNbO3 crystal is demonstrated. Quasi phase matching is obtained by periodically lowering the nonlinear refractive index of the crystal using focussed ultrashort pulses. The structures were used to frequency double 1.55 µm light. The converted signal could be enhanced by a factor of 70 with respect to the unmodified material. From these measurement it could be deduced that the nonlinearity has been periodically damped up to 20%.
Sales Growth Through Strategic Leadership
Authors: Hatami Homayoun , Prince Sara , de Uster Maria Valdivieso
Published: March 2013

In today's business environment, achieving growth is difficult, but “opportunities do exist for companies with the skill and the courage to find them,” the authors write. Strong leaders challenge how work is done, galvanize a company's teams, model positive change, and get personally involved in the process, while avoiding micromanagement. Based on research at their organization, McKinsey & Company, the authors relate that most change programs fail due to employee resistance, management that doesn't support change, and resource/budget issues. Change requires considerable daily work, “but a well‐designed and well‐executed program is worth what may become years of effort.”
Direct Adhesion of Endothelial Cells to Bioinspired Poly(dopamine) Coating Through Endogenous Fibronectin and Integrin α5β1
Authors: Wang Jin‐Lei , Ren Ke‐Feng , Chang Hao , Jia Fan , Li Bo‐Chao , Ji Ying , Ji Jian
Published: March 2013

Mussel‐inspired poly(dopamine) (PDA) coating is proven to be a simple, versatile, and effective strategy to promote cell adhesion onto various substrates. In this study, the initial adhesive behavior of human umbilical vein endothelial cells (HUVECs) is evaluated on a PDA coating under serum‐free conditions. It is found that HUVECs can attach directly to and spread with well‐organized cytoskeleton and fibrillar adhesions on the PDA surface, whereas cells adhere poorly to and barely spread on the control polycaprolactone surface. Endogenous fibronectin and α5β1 integrin are found to be involved in the cell adhesion process. These findings will lead to a better understanding of interactions between cells and PDA coating, paving the way for the further development of PDA.

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Flame‐retardant and mechanical properties of phenolic foams toughened with polyethylene glycol phosphates
Authors: Sui Xiaoyu , Wang Zhengzhou
Published: March 2013

Three kinds of polyethylene glycol phosphates (PEGPs) toughening agents were synthesized by esterification of phosphorus pentoxide (P2O5) with polyethylene glycol and characterized by Fourier transform infrared spectra and 31P nuclear magnetic resonance. A series of lightweight phenolic foams toughened with different loadings of PEGPs were prepared. Optical microscopy results show that the addition of PEGPs with small molecular weight PEG improves the structural homogeneity of phenolic foams obviously. The flame retardancy of toughened phenolic foams was evaluated by using UL 94, limiting oxygen index, and cone calorimeter. The results indicate that the incorporation of PEGPs not only increases the toughness of phenolic foams but also improves their flame retardancy. Moreover, the thermal stability of PEGPs and the toughened foams was investigated by thermogravimetric analysis. Copyright © 2013 John Wiley & Sons, Ltd.
Severe Hypoglycemia from Helicobacter Pylori Triple‐Drug Therapy and Insulin Detemir Drug Interaction
Authors: Otsuka Shelley H.
Published: March 2013

Two drugs commonly used in triple‐drug therapy for treatment of a Helicobacter pylori infection, clarithromycin and omeprazole, have rarely been associated with hypoglycemia when given alone. No documented interactions between H. pylori treatment with clarithromycin, amoxicillin, and omeprazole and insulin detemir have been previously reported. This case report describes an 82‐year‐old man with drug‐controlled type 2 diabetes who experienced severe hypoglycemia during treatment for a H. pylori infection in an outpatient setting. His diabetes treatment included 32 units of insulin detemir once/day at bedtime and insulin aspart, determined by carbohydrate intake, 3 times/day with meals. After 5 days of clarithromycin 500 mg twice/day, amoxicillin 500 mg twice/day, and omeprazole 20 mg twice/day for treatment of the H. pylori infection, the patient experienced hypoglycemia and self‐discontinued clarithromycin. Insulin detemir was decreased to 15 units and hypoglycemia reoccurred. Insulin detemir was further decreased to 10 units without further symptoms of hypoglycemia for the remainder of the H. pylori treatment. Once treatment was completed, the patient was instructed to resume taking 32 units of insulin detemir once/day. His blood glucose concentration returned to a baseline value, and he denied experiencing further hypoglycemic episodes. Health care practitioners should be aware of this possible drug interaction and anticipate that insulin detemir dosage adjustments may be required during treatment of H. pylori infection to avoid significant adverse events.
Instability of the chiral phase and electronic ferroelectricity in the extended Falicov–Kimball model
Authors: Golosov D. I.
Published: March 2013

We consider a spinless extended Falicov–Kimball model (EFKM) at half‐filling, for the case of opposite‐parity bands. Within the Hartree–Fock approach, we calculate the excitation energies in the chiral phase, which is a possible mean‐field solution in the presence of a hybridisation. It is shown that the chiral phase is unstable. We then briefly review the accumulated results on stability and degeneracies of the excitonic insulator phase. Based on these, we conclude that the presence of both hybridisation and narrow‐band hopping is required for electronic ferroelectricity (EFE).
An investigation on TCP large initial window
Authors: Biswas Israfil
Published: March 2013

Transport layer implicates a position where satellite networks form one integrated component of hybrid Internet architecture in today's advance technology. However, the Internet has emerged with an important new class of applications that exhibits significant variations of transmission rate over time. Variable‐rate traffic poses a new challenge for transmission control protocol that provides congestion control, especially for applications that need to share the limited capacity of a bottleneck over a long delay Internet path (e.g. paths that include satellite links). Variable‐rate traffic can be produced by persistent transmission control protocol connections and can be impacted by the initial window at the start or during the restart of a session. Current transport research issues are identified related to larger initial window to highlight the expected performance benefits and derive the implications on the design of geostationary satellite Internet systems as the network evolves toward a next‐generation Internet. Copyright © 2013 John Wiley & Sons, Ltd.
Mapping and modeling of physician collaboration network
Authors: Uddin Shahadat , Hamra Jafar , Hossain Liaquat
Published: March 2013

Effective provisioning of healthcare services during patient hospitalization requires collaboration involving a set of interdependent complex tasks, which needs to be carried out in a synergistic manner. Improved patients' outcome during and after hospitalization has been attributed to how effective different health services provisioning groups carry out their tasks in a coordinated manner. Previous studies have documented the underlying relationships between collaboration among physicians on the effective outcome in delivering health services for improved patient outcomes. However, there are very few systematic empirical studies with a focus on the effect of collaboration networks among healthcare professionals and patients' medical condition. On the basis of the fact that collaboration evolves among physicians when they visit a common hospitalized patient, in this study, we first propose an approach to map collaboration network among physicians from their visiting information to patients. We termed this network as physician collaboration network (PCN). Then, we use exponential random graph (ERG) models to explore the microlevel network structures of PCNs and their impact on hospitalization cost and hospital readmission rate. ERG models are probabilistic models that are presented by locally determined explanatory variables and can effectively identify structural properties of networks such as PCN. It simplifies a complex structure down to a combination of basic parameters such as 2‐star, 3‐star, and triangle. By applying our proposed mapping approach and ERG modeling technique to the electronic health insurance claims dataset of a very large Australian health insurance organization, we construct and model PCNs. We notice that the 2‐star (subset of 3 nodes in which 1 node is connected to each of the other 2 nodes) parameter of ERG has significant impact on hospitalization cost. Further, we identify that triangle (subset of 3 nodes in which each node is connected to the rest 2 nodes), alternative k‐star (subset of k nodes in which 1 node is connected to each of other k − 1 nodes), and alternative k − 2 path (subset of k nodes in which, between a specific pair of nodes, there exists k − 2 paths of length 2) parameters of ERG have impact on the hospital readmission rate. Our findings can have implications for healthcare administrators or managers who could potentially improve the practice cultures in their organizations by following these outcomes. Copyright © 2013 John Wiley & Sons, Ltd.
Evolution of Published Research on Molten Slags and Fluxes in the Second Millennium
Authors: Boom Rob , Riaz Shahid , Xiao Yanping , Mills Kenneth C.
Published: March 2013

Starting in 1997 with the 5th International Conference on Slags and Fluxes, a survey on research on slags has been carried out for every conference on slags and fluxes. Trends from 1980, the year of the first conference in Halifax, Canada, have been traced and discussed. For the ninth conference in the series, the survey is focused on research on molten slags and fluxes published from 2000 to 2010. In these 10 years, the center of gravity of the metals industry has shifted eastwards towards China, and the slags and fluxes literature follows this geographical shift with reference to numbers of papers published per annum. The increased attention on sustainable metals production (including recycling of valuable metals and reuse of slags as cement or construction material) is reflected in the type of research on slags. Minimization of slag production per unit of metal produced is another trend triggering innovative production process development. An in‐depth analysis is given of papers published in 2010 in selected journals from China, Europe and USA in terms of slag systems, type of research and geographical origin.
Characteristics of Alumina‐Based Inclusions in Low Carbon Al‐Killed Steel under No‐Stirring Condition
Authors: Yang Wen , Wang Xinhua , Zhang Lifeng , Wang Wanjun
Published: March 2013

Alumina‐based inclusions have a detrimental effect on castability and the surface quality of the LCAK steel sheet, thus they are expected to be removed from the steel. In order to get the detailed transient characteristics of inclusion aggregation and removal after Al addition, laboratory experiments were performed to study the formation of alumina inclusions during Al‐killed process of low carbon steel at 1873 K under no‐stirring condition. The characteristics of the alumina‐based inclusions in terms of amount, size, and morphology were investigated. The results showed that the evolution of the AF (area fraction) and average size of Al2O3 inclusions after deoxidation was divided into three stages: 0–9 min, aggregation was dominant; 9–22 min, floating was dominant; after 22 min, both the AF and size decreased slowly. Accordingly, the stirring was suggested to be strengthened in the initial 9 min under stirring condition to promote the removal of large inclusions. Based on the correlation between inclusion morphology and holding time, a simple precipitation and growth mechanism of alumina inclusions was proposed, which consisted of three main stages: precipitation stage of Al2O3 single particles, aggregation stage, and sintering stage of aggregated inclusions. And it was implied that the Ostwald‐Ripening can be finished up within 20 min.
Avoidance of Calibrating Errors with Viscosity Measurements of Metallurgical Slags
Authors: Heller Hans‐Peter , Hötzel Michael , Lychatz Bernd , Haustein Nicole
Published: March 2013

For the investigation of rheological features like dynamic viscosity, a high temperature rheometer was able to be successfully established at the Institute of Iron and Steel Technology of the TU Bergakademie Freiberg. Based on known calibration problems with high‐level pyrometries, the viscosity was calculated directly without calibration. This is possible with an air‐bearing rheometer and exact absolute torque measurement via the electrical parameters of the drive and via movement parameters and geometry of the measuring pairing. This technique meets the desired requirements in view of measuring accuracy and reproducibility of the measured results. The measurements were carried out on silicone oils in the low temperature range under dynamic conditions. It was demonstrated that the silicone oils are suited for comparative measurements under different rheological conditions. The results from the comparison of the two measuring systems (CPM and CCM in high temperature configuration) have shown that, in the high‐level temperature range, a measurement error <1% is to be expected.
Power‐aware range‐free wireless sensor network localization using neighbor distance distribution
Authors: Gopakumar Aloor , Jacob Lillykutty
Published: March 2013

In large‐scale wireless sensor networks, cost‐effective and energy‐efficient localization of sensor nodes is an important research topic. In spite of their coarse accuracy, range‐free (connectivity‐based) localization methods are considered as cost‐effective alternatives to the range‐based localization schemes with specialized hardware requirements.In this paper, we derive closed‐form expressions for the average minimum transmit powers required for the localization of sensor nodes, under deterministic path loss, log‐normal shadowing, and Rayleigh fading channel models. The impacts of propagation environment and spatial density of anchor nodes on the minimum transmit power for node localization are evaluated analytically as well as through simulations. Knowledge of the minimum transmit power requirements for localizability of a sensor node enables improving energy efficiency and prolonging lifetime of the network. We also propose a novel distance metric for range‐free localization in large‐scale sensor networks. The target and anchor nodes are assumed to be positioned according to two statistically independent two‐dimensional homogeneous Poisson point processes. Analytical expression for the average distance from a target node to its kth nearest neighbor anchor node is derived and is used for estimating the target‐to‐anchor node distances for localization. The Cramér–Rao lower bound on the localization accuracy for the new distance estimator is derived. Simulation results show the accuracy of the proposed distance estimate compared with some existing ones for range‐free localization. The results of our investigation are significant for low‐cost, energy‐efficient localization of wireless sensor nodes. Copyright © 2011 John Wiley & Sons, Ltd.
Extending P2PMesh: topology‐aware schemes for efficient peer‐to‐peer data sharing in wireless mesh networks
Authors: Alasaad Amr , Gopalakrishnan Sathish , Leung Victor C.M.
Published: March 2013

Wireless mesh networks (WMNs) have emerged as a promising technology that provides low‐cost broadband access to the Internet for fixed and mobile wireless end users. An orthogonal evolution in computer networking has been the rise of peer‐to‐peer (P2P) applications such as P2P data sharing. It is of interest to enable effective P2P data sharing in this type of networks. Conventional P2P data sharing systems are not cognizant of the underlying network topology and therefore suffer from inefficiency. We argue for dual‐layer mesh network architecture with support from wireless mesh routers for P2P applications. The main contribution of this paper is P2PMesh: a topology‐aware system that provides combined architecture and efficient schemes for enabling efficient P2P data sharing in WMNs. The P2PMesh architecture utilizes three schemes: (i) an efficient content lookup that mitigates traffic load imbalance at mesh routers; (ii) an efficient establishment of download paths; and (iii) a data transfer protocol for multi‐hop wireless networks with limited capacity. We note here that the path establishment and data transfer schemes are specific to P2P traffic and that other traffic would use routes determined by the default routing protocol in the WMN. Simulation results suggest that P2PMesh has the potential to improve the performance of P2P applications in a wireless multi‐hop setting; specifically, we focused on data sharing, but other P2P applications can also be supported by this approach. Copyright © 2011 John Wiley & Sons, Ltd.
Quality of service‐aware coordinated dynamic spectrum access: prioritized Markov model and call admission control
Authors: Jiang Xueyuan , Zhang Yangyang , Wong Kai‐Kit , Kim Jae Moung , Edwards David J.
Published: March 2013

In this paper, we propose a heterogeneous‐prioritized spectrum sharing policy for coordinated dynamic spectrum access networks, where a centralized spectrum manager coordinates the access of primary users (PUs) and secondary users (SUs) to the spectrum. Through modeling the access of PUs and multiple classes of SUs as continuous‐time Markov chains, we analyze the overall system performance with consideration of a grade‐of‐service guarantee for both the PUs and the SUs. In addition, two new call admission control (CAC) strategies are devised in our models to enhance the maximum admitted traffic of SUs for the system. Numerical results show that the proposed heterogeneous‐prioritized policy achieves higher maximum admitted traffic for SUs. The trade‐off between the system's serving capability and the fairness among multiple classes of SUs is also studied. Moreover, the proposed CAC strategies can achieve better performance under max‐sum, proportional, and max‐min fairness criteria than the conventional CAC strategies. Copyright © 2011 John Wiley & Sons, Ltd.
Preparation of progenin III from total steroidal saponins of Dioscorea nipponica Makino using a crude enzyme from Aspergillus oryzae strain
Authors: Liu Tingqiang , Yu Hongshan , Liu Chunying , Bao Yongming , Hu Xiangchun , Wang Yuanhao , Liu Bing , Fu Yaoyao , Tang Sihui , Jin Fengxie
Published: March 2013

Progenin III, one of the most active spirostanol saponins, is a potential candidate for anti-cancer therapy due to its strong antitumor activity and low hemolytic activity. However, the concentration of progenin III is extremely low in natural Dioscorea plants. In this paper, the progenin III production from total steroidal saponins of Dioscorea nipponica Makino was studied using the crude enzyme from Aspergillus oryzae DLFCC-38. The crude enzyme converting total steroidal saponins into progenin III was obtained from the A. oryzae DLFCC-38 culture. For enzyme production, the strain was cultured for 72 h at 30 °C with shaking at 150 rpm in 5 % (w/v) malt extract medium containing 2 % (v/v) extract of D. nipponica as the enzyme inducer. The crude enzyme converted total steroidal saponins into major progenin III with a high yield when the reaction was carried out for 9 h at 50 °C and pH 5.0 with the 20 mg/ml of substrate. In the preparation of progenin III, 117 g of crude progenin III was obtained from 160 g of substrate, and the crude product was purified with silica gel column to obtain 60.3 g progenin III of 93.4 % purity.
Gender Differences on Ultrasound Imaging of Lateral Abdominal Muscle Thickness in Asymptomatic Adults: A Pilot Study
Authors: Rho Monica , Spitznagle Theresa , Van Dillen Linda , Maheswari Vaibhav , Oza Sonal , Prather Heidi
Published: March 2013

Objective

To describe gender and side‐to‐side differences in lateral abdominal wall muscle thickness at rest and during contraction in asymptomatic adults.

Design

Cross‐sectional observational study.

Setting

Tertiary university outpatient musculoskeletal clinic.

Patients

Asymptomatic, healthy adults.

Methods

A single examiner with training in ultrasound (US) assessment evaluated all subjects and used a different hand to guide the US transducer on each side. Bilateral anteroposterior measurements of transversus abdominis (TrA) and internal oblique (IO) thickness were assessed at rest and during maximal contraction with the use of an abdominal draw‐in maneuver (ADM). Three sets of data points were obtained on 12 subjects to determine intrarater reliability within a single session.

Main Outcome Measurements

Anteroposterior thickness of TrA and IO muscles (cm).

Results

A total of 20 subjects (mean age, 29.3 years; range, 23‐46 years; 8 men and 12 women; mean body mass index, 24.4 kg/m2; range, 18.9‐34.9 kg/m2) were examined. At rest, men had greater TrA and IO thickness compared with women (men, 0.55, and women, 0.35, P = .01; and men, 0.95, and women, 0.77, P = .04, respectively). At rest, there were no side‐to‐side differences of TrA or IO muscles for both genders. With an ADM, women demonstrated a significant percent change in thickness of their TrA muscle compared with men (women, 0.77, and men, 0.29, P = .001). No significant difference was found between men and women in the percent change of IO thickness with ADM (women, 0.20, and men, 0.12, P = .24). There was excellent intrarater reliability for measurements of the right abdominal muscles (intraclass correlation coefficient = 0.92‐0.95) and moderate‐to‐good intrarater reliability for measurements of the left abdominal muscles (intraclass correlation coefficient = 0.62‐0.92).

Conclusions

Asymptomatic men have greater TrA and IO thickness at rest compared with asymptomatic women; however, women demonstrated a greater percent change in TrA thickness with an ADM compared with men.
White Matter Hyperintensity Burden and Disability in Older Adults: Is Chronic Pain a Contributor?
Authors: Buckalew Neilly , Haut Marc W. , Aizenstein Howard , Rosano Caterina , Edelman Kathryn Dunfee , Perera Subashan , Marrow Lisa , Tadic Stasa , Venkatraman Vijay , Weiner Debra
Published: March 2013

Objective

To primarily explore differences in global and regional white matter hyperintensities (WMH) in older adults with self‐reported disabling and nondisabling chronic low back pain (CLBP) and to examine the association of WMH with gait speed in all participants with CLBP. To secondarily compare WMH of the participants with CLBP with the pain‐free controls.

Design

A cross‐sectional, case‐control study.

Setting

University of Pittsburgh.

Participants

Twenty‐four community‐dwelling older adults: 8 with self‐reported disabling CLBP, 8 with nondisabling CLBP, and 8 were pain‐free. Exclusions were psychiatric or neurologic disorders (either central or peripheral), substance abuse, opioid use, or diabetes mellitus.

Methods

All participants underwent structural brain magnetic resonance imaging, and all participants with CLBP underwent the 4‐m walk test.

Main Outcome Measurements

All the participants were assessed for both global and regional WMH by using an automated localization and segmentation method, and gait speed of participants with CLBP.

Results

The disabled group demonstrated statistically significant regional WMH in a number of left hemispheric tracts: anterior thalamic radiation (P = .0391), lower cingulate (P = .0336), inferior longitudinal fasciculus (P = .0367), superior longitudinal fasciculus (P = .0011), and the superior longitudinal fasciculus branch to the temporal lobe (P = .0072). Also, there was a statistically significant negative association (rs = −0.57; P = .0225) between the left lower cingulate WMH and the gait speed in all the participants with CLBP. There was a statistical difference in global WMH burden (P = .0014) and nearly all regional tracts (both left and right hemispheres) when comparing CLBP with pain‐free participants.

Conclusions

Our findings suggest that WMH is associated with, and hence, may be accelerated by chronic pain manifesting as perceived disability, given the self‐reported disabled CLBP patients had the greatest burden, and the pain free the least, and manifesting as measurable disability, given increasing WMH was associated with decreasing gait speed in all chronic pain participants.
Game theory-based negotiation for multiple robots task allocation
Authors: Cui Rongxin , Guo Ji , Gao Bo
Published: March 2013

This paper investigates task allocation for multiple robots by applying the game theory-based negotiation approach. Based on the initial task allocation using a contract net-based approach, a new method to select the negotiation robots and construct the negotiation set is proposed by employing the utility functions. A negotiation mechanism suitable for the decentralized task allocation is also presented. Then, a game theory-based negotiation strategy is proposed to achieve the Pareto-optimal solution for the task reallocation. Extensive simulation results are provided to show that the task allocation solutions after the negotiation are better than the initial contract net-based allocation. In addition, experimental results are further presented to show the effectiveness of the approach presented.
Physicochemical and biological dynamics in a coastal Antarctic lake as it transitions from frozen to open water
Authors: Dieser Markus , Foreman Christine M. , Jaros Christopher , Lisle John T. , Greenwood Mark , Laybourn-Parry Johanna , Miller Penney L. , Chin Yu-Ping , Mcknight Diane M.
Published: March 2013

Pony Lake, at Cape Royds, Antarctica, is a shallow, eutrophic, coastal lake that freezes solid in the winter. Changes in Pony Lake's physicochemical parameters and microbial community were studied during the transition from ice to open water. Due to rising water temperatures, the progressive melt of the ice column and the gradual mixing of basal brines into the remaining water column, Pony Lake evolved physically and chemically over the course of the summer, thereby affecting the microbial community composition. Temperature, pH, conductivity, nutrients and major ion concentrations reached their maximum in January. Pony Lake was colonized by bacteria, viruses, phytoflagellates, ciliates, and a small number of rotifers. Primary and bacterial production were highest in mid-December (2.66 mg C l-1d-1and 30.5 μg C l-1d-1, respectively). A 16S rRNA gene analysis of the bacterioplankton revealed 34 unique sequences dominated by members of theβ- andγ-proteobacterialineages. Cluster analyses on denaturing gradient gel electrophoresis (DGGE) banding patterns and community structure indicated a shift in the dominant members of the microbial community during the transition from winter ice, to early, and late summer lakewater. Our data demonstrate that temporal changes in physicochemical parameters during the summer months determine community dynamics and mediate changes in microbial species composition.
NONCONNECTEDNESS OF THE SET OF BANKRUPTCY-FREE MONEY EQUILIBRIA IN THE STATIC ECONOMY: A CONSTRUCTIVE EXAMPLE
Authors: Kang Minwook
Published: March 2013

A static economy in which nominal taxes and transfers are balanced, as proposed by Balasko and Shell (1993), typically has a continuum of equilibrium money prices. This paper presents a constructive example in which the set of equilibrium money prices is not connected. By allowing negative consumption as a mathematical construct, closed form solutions for equilibrium tax-adjusted income are derived. The main result of the example implies that bankrupt taxpayers with negative tax-adjusted income can be free from bankruptcy as the price of money increases. This paradoxical outcome is similar to that of the transfer paradox, as suggested by Gale (1974), where tax-transfer plans make taxpayers better off.
Cyberball
Authors: Ruggieri Sabrina , Bendixen Mons , Gabriel Ute , Alsaker Françoise
Published: March 2013

We examined the effects of ostracism in early adolescent populations using the cyberball paradigm ( Williams, Cheung, & Choi, 2000 ). Ninety-one Swiss school students, aged 10–14 years, were randomly assigned to the ostracism (24 girls, 23 boys) or the inclusion (23 girls, 21 boys) condition and were led to believe that they were playing cyberball with two other same-sex students. In reality, they were computer-generated confederates. We assessed self-reported levels of mood before and after playing the game as well as sense of belonging, self-esteem, meaningful existence, and control after the game. Compared to nonostracized students, adolescents in the ostracism condition reported significantly lower levels of positive mood after playing the game. Furthermore, they reported a lower sense of belonging and lower levels of self-esteem, meaningful existence, and control. The present results from a non-English-speaking sample correspond well to the few earlier findings in adolescent and adult populations by suggesting that even brief periods of ostracism with unknown others can lead to a significant decrease in well-being in these age groups.
Knockdown of cathepsin D in zebrafish fertilized eggs determines congenital myopathy
Authors: Follo Carlo , Ozzano Matteo , Montalenti Claudia , Santoro Massimo Mattia , Isidoro Ciro
Published: March 2013

CD (cathepsin D) is a ubiquitous lysosomal hydrolase involved in a variety of pathophysiological functions, including protein turnover, activation of pro-hormones, cell death and embryo development. CD-mediated proteolysis plays a pivotal role in tissue and organ homoeostasis. Altered expression and compartmentalization of CD have been observed in diseased muscle fibres. Whether CD is actively involved in muscle development, homoeostasis and dystrophy remains to be demonstrated. Zebrafish (Danio rerio) is emerging as a valuable ‘in vivo’ vertebrate model for muscular degeneration and congenital myopathies. In this work, we report on the perturbance of the somitic musculature development in zebrafish larvae caused by MPO (morpholino)-mediated silencing of CD in oocytes at the time of fertilization. Restoring CD expression, using an MPO-non-matching mutated mRNA, partially rescued the normal phenotype, confirming the indispensable role of CD in the correct development and integrity of the somitic musculature. This is the first report showing a congenital myopathy caused by CD deficiency in a vertebrate experimental animal model.
Changes in retinal aquaporin-9 (AQP9) expression in glaucoma
Authors: Yang Ming-Hui , Dibas Adnan , Tyan Yu-Chang
Published: March 2013

The eye contains numerous water channel proteins and the roles of AQPs (aquaporins) in the retina are blurred, especially under disease conditions. The purpose of this study was to investigate the expression of AQP9 gene and proteins affected by elevated IOP (intraocular pressure) in a rat model of glaucoma induced by intravitreous injection of hypertonic saline into the episcleral veins. The gene and protein expressions of AQP9 were investigated by real-time PCR and Western blotting. The immunoreactive expression of AQP9, AQP4 and GFAP (glial fibrillary acidic protein) in the optic nerve of rats exposed to experimentally elevated IOP was detected by immunofluorescence microscopy. The mRNA and protein expression levels of AQP9 were up-regulated in the retina of an animal model of glaucoma. The immunoreactivities of the AQP9, AQP4 and GFAP were also detected and increased in the optic nerve region. The expression of AQP9 was up-regulated in this glaucoma model and the immunoreactivities of the AQP4 and GFAP were also detected as co-localizing with AQP9 in the optic nerve region, indicating retina ganglion cells were surrounded by activated astrocytes. This may indicate that the injured neurons may rely on the astrocytes. The alterations of AQP expression may compensate the glaucomatous damage.