bluuebunny/crossref_metadata_2025 huggingface dataset:
Amplatzer left atrial appendage occlusion: Single center 10‐year experience
Authors: Nietlispach Fabian , Gloekler Steffen , Krause René , Shakir Samera , Schmid Michael , Khattab Ahmed A. , Wenaweser Peter , Windecker Stephan , Meier Bernhard
Published: February 2013

Objectives

To report a 10‐year single center experience with Amplatzer devices for left atrial appendage (LAA) occlusion.

Background

Intermediate‐term outcome data following LAA occlusion are scarce.

Methods

Short‐ and intermediate‐term outcomes of patients who underwent LAA occlusion were assessed. All procedures were performed under local aesthesia without transesophageal echocardiography. Patients were discharged on acetylsalicylic acid and clopidogrel for 1–6 months.

Results

LAA occlusion was attempted in 152 patients (105 males, age 72 ± 10 years, CHA2DS2‐Vasc‐score 3.4 ± 1.7, HAS‐BLED‐score 2.4 ± 1.2). Nondedicated devices were used in 32 patients (21%, ND group) and dedicated Amplatzer Cardiac Plugs were used in 120 patients (79%, ACP group). A patent foramen ovale or atrial septal defect was used for left atrial access and closed at the end of LAA occlusion in 40 patients. The short‐term safety endpoints (procedural complications, bleeds) occurred in 15 (9.8%) and the efficacy endpoints (death, stroke, systemic embolization) in 0 patients. Device embolization occurred more frequently in the ND as compared to the ACP group (5 patients or 12% vs. 2 patients or 2%). Mean intermediate‐term follow up of the study population was 32 months (range 1–120). Late deaths occurred in 15 patients (5 cardiovascular, 7 noncardiac, 3 unexplained). Neurologic events occurred in 2, peripheral embolism in 1, and major bleeding in 4 patients. The composite efficacy and safety endpoint occurred in 7% and 12% of patients.

Conclusion

LAA closure may be a good alternative to oral anticoagulation. This hypothesis needs to be tested in a randomized clinical trial to ensure that all potential biases of this observational study are accounted for. © 2013 Wiley Periodicals, Inc.
Shifting Troubles: Decision‐Making versus Implementation in Participatory Watershed Governance
Authors: Roggero Matteo
Published: February 2013

We explore the implementation of the European Water Framework Directive from the point of view of institutional economics, focusing on participation in the introduction of management plans. The design of participatory processes is linked with decision‐making and implementation costs through an analytical model. The model is subsequently applied to qualitative evidence from four different empirical cases. The analysis reveals similarities between widely heterogeneous cases: process design choices seem generally to economize on decision‐making costs. The paper discusses the implications of these findings for policy implementation and future research. Copyright © 2013 John Wiley & Sons, Ltd and ERP Environment.
Managing Socio‐Ecological Systems to Achieve Sustainability: A Study of Resilience and Robustness
Authors: Domptail Stephanie , Easdale Marcos H. , Yuerlita
Published: February 2013

Growing symptoms of the mismanagement of socio‐ecological systems (SESs) show that the long‐term existence of these systems is threatened. SES management improvement is the aim of many policy measures. But how successful are these various simultaneous policy measures in achieving the sustainable management of SESs? A framework for analysing policy measures and the management actions of land users was developed by Leach et al. (2010): the authors postulate that the sustainability of an SES depends on four system properties – stability, resilience, durability and robustness – and that external shocks and stresses affect these properties differently. The aim of this contribution is to identify the strengths and weaknesses of the approach by applying it to three case studies, in Namibia, Argentina and Indonesia. We found that (1) more actions were directed towards resilience and robustness than towards command and control, (2) actions directed at stability and durability were generally undertaken at the national level and (3) the introduction of the concept of robustness to illustrate the property of adaptability enables the identification of trade‐offs among properties, but (4) issues of ecological degradation were difficult to address explicitly. We consider that the framework can make a useful contribution to policy making by framing the impact of a given intervention on SESs on the four key system properties. Yet, the framework provides a structure to make ex‐post assessment of SES management or to formulate assumptions about potential synergies/trade‐offs among impacts on system properties. However, we suggest using it as complementary to other policy impact assessment methods. Copyright © 2013 John Wiley & Sons, Ltd and ERP Environment.
Measuring Hedging Effectiveness of Index Futures Contracts: Do Dynamic Models Outperform Static Models? A Regime‐Switching Approach
Authors: Salvador Enrique , Aragó Vicent
Published: February 2013

This study estimates linear and nonlinear GARCH models to find optimal hedge ratios with futures contracts for some of the main European stock indexes. By introducing nonlinearities through a regime‐switching model, we can obtain more efficient hedge ratios and superior hedging performance in both an in‐sample and an out‐sample analysis compared to the other methodologies (constant hedge ratios and linear GARCH). Moreover, nonlinear models also reflect the different patterns followed by the dynamic relationship between the volatility of spot and futures returns during low‐ and high‐volatility periods. © 2013 Wiley Periodicals, Inc. Jrl Fut Mark 34:374–398, 2014
Contemporaneous Spill‐Over Among Equity, Gold, and Exchange Rate Implied Volatility Indices
Authors: Badshah Ihsan Ullah , Frijns Bart , Tourani‐Rad Alireza
Published: February 2013

This paper examines the contemporaneous spill‐over effects among the implied volatility indices for stocks (VIX), gold (GVZ), and the exchange rate (EVZ). Using the “identification through heteroskedasticity” approach of Rigobon (2003), we decompose the contemporaneous relationships between these indices into causal relationships. We find strong unidirectional spill‐over from VIX to GVZ and EVZ (increases in VIX lead to increases in GVZ and EVZ); and bi‐directional spill‐over between GVZ and EVZ. The impulse responses of our structural VAR suggest that the traditional VAR seriously overestimates the impulse responses for GVZ and EVZ. These findings have important implications for portfolio and risk management.
The North Pacific High and wintertime pre‐conditioning of California current productivity
Authors: Schroeder Isaac D. , Black Bryan A. , Sydeman William J. , Bograd Steven J. , Hazen Elliott L. , Santora Jarrod A. , Wells Brian K.
Published: February 2013

Variations in large‐scale atmospheric forcing influence upwelling dynamics and ecosystem productivity in the California Current System (CCS). In this paper, we characterize interannual variability of the North Pacific High over 40 years and investigate how variation in its amplitude and position affect upwelling and biology. We develop a winter upwelling “pre‐conditioning” index and demonstrate its utility to understanding biological processes. Variation in the winter NPH can be well described by its areal extent and maximum pressure, which in turn is predictive of winter upwelling. Our winter pre‐conditioning index explained 64% of the variation in biological responses (fish and seabirds). Understanding characteristics of the NPH in winter is therefore critical to predicting biological responses in the CCS.
Estimating the effect of Earth elasticity and variable water density on tsunami speeds
Authors: Tsai Victor C. , Ampuero Jean‐Paul , Kanamori Hiroo , Stevenson David J.
Published: February 2013

The speed of tsunami waves is typically calculated using the shallow‐water approximation over a rigid‐body Earth. Recent comparisons of tsunami arrival times from the 11 March 2011 tsunami suggest, however, that the standard formulation has errors around the 1% level, and it has been suggested that the elasticity of the Earth can explain the discrepancy. While previous work has indeed shown that such elastic deformation can modify tsunami speeds, the effect has been neglected partly due to the difficulty in understanding how large this elastic effect is. Here, we remedy this by providing a new derivation and expression for how to incorporate the first‐order effect that solid Earth elasticity and ocean water compressibility have on tsunami speeds. This result is shown to agree approximately with previous theory and helps to explain observed timing discrepancies from the 11 March 2011 tsunami. The dispersive elastic correction and the non‐dispersive compressibility correction together may account for the majority of the observed discrepancy.
Effect of the largest foreshock (Mw 7.3) on triggering the 2011 Tohoku earthquake (Mw 9.0)
Authors: Gusman Aditya Riadi , Fukuoka Mitsuteru , Tanioka Yuichiro , Sakai Shin'ichi
Published: February 2013

The slip distribution of the largest foreshock that occurred 2 days before the mainshock of the 2011 Tohoku earthquake is estimated by tsunami waveform inversion. The major slip region was located on the down‐dip side of the hypocenter, and the slip amounts ranged from 0.6 to 1.5 m. By assuming the rigidity of 4 × 1010 N m‐2, the seismic moment calculated from the slip distribution is 1.2 × 1020 N m (Mw 7.3). The slip distribution suggests that the largest foreshock did not rupture the plate interface where the dynamic rupture of the mainshock was initiated. The largest foreshock increased the Coulomb stress (1.6–4.5 bars) on the plate interface around the hypocenter of the mainshock. This indicates that the 2011 Tohoku earthquake was brought closer to failure by the largest foreshock.
Shock compression of Fe‐FeS mixture up to 204 GPa
Authors: Huang Haijun , Wu Shijie , Hu Xiaojun , Wang Qingsong , Wang Xiang , Fei Yingwei
Published: February 2013

Using a two‐stage light gas gun, we obtained new shock wave Hugoniot data for an iron‐sulfur alloy (Fe‐11.8wt%S) over the pressure range of 94–204 GPa. A least‐squares fit to the Hugoniot data yields a linear relationship between shock velocity DS and particle velocity u, DS (km/s) =3.60(0.14) +1.57(0.05) u. The measured Hugoniot data for Fe‐11.8wt%S agree well with the calculated results based on the thermodynamic parameters of Fe and FeS using the additive law. By comparing the calculated densities along the adiabatic core temperature with the PREM density profile, an iron core with 10 wt.% sulfur (S) provides the best solution for the composition of the Earth's outer core.
Observing the bottom density current over a shelf using an Argo profiling float
Authors: Vilibić Ivica , Mihanović Hrvoje
Published: February 2013

Pressure, temperature, and salinity data collected during the winter of 2011/2012 by an Argo profiling float over the Adriatic shelf were used to document the dense water formation and subsequent bottom density current (BDC) normally occurring along the shelf slope. The float was advected to the Jabuka Pit and neighboring shallow area (<275 m) after October 2010. The parking depth was set to approximately 150 m, enabling the float to mostly follow the firstOnlineseabed between December 2011 and July 2012. The profiler measured strong spatial‐temporal changes in the BDC thickness (from a few to about 50 m) and the bottom density (between 29.46 and 29.88 kg/m3). These observations show that an Argo float has the capability to observe a bottom density current and suggest that it would be possible to systematically use such floats to investigate these processes on coastal shelves.
Observed and simulated variability of the AMOC at 26°N and 41°N
Authors: Mielke C. , Frajka‐Williams E. , Baehr J.
Published: February 2013

Time series of the observational estimate of the Atlantic meridional overturning circulation (AMOC) have recently become available, but so far, no contemporaneous relation has been documented between them. Here, we analyze the variability of the 26°N Rapid Climate Change programme (RAPID) and the 41°N Argo‐based AMOC estimates on seasonal timescales, and we compare them to a simulation from a high‐resolution National Centers for Environmental Prediction (NCEP)‐forced ocean model. In our analysis of the observed time series, we find that the seasonal cycles of the non‐Ekman component of the AMOC between 26°N and 41°N are 180‐degrees out‐of‐phase. Removing the mean seasonal cycle from each time series, the residuals have a non‐stationary covariability. Our results demonstrate that the AMOC is meridionally covariable between 26°N and 41°N at seasonal timescales. We find the same covariability in the model, although the phasing differs from the observed phasing. This may offer the possibility of inferring AMOC variations and associated climate anomalies throughout the North Atlantic from discontinuous observations.
DOES FISCAL DISCIPLINE TOWARDS SUBNATIONAL GOVERNMENTS AFFECT CITIZENS' WELL‐BEING? EVIDENCE ON HEALTH
Authors: Piacenza Massimiliano , Turati Gilberto
Published: February 2013

This paper aims to assess the impact on citizens' well‐being of fiscal discipline imposed by the central government on subnational governments. Because healthcare policies involve strategic interactions between different layers of governments in many different countries, we focus on a particular dimension of well‐being, namely citizens' health. We model fiscal discipline by considering government expectations of future deficit bailouts from the central government. We then study how these bailout expectations affect the expenditure for healthcare policies carried out by decentralized governments. To investigate this issue, we separate efficient health spending from inefficiencies by estimating an input requirement frontier. This allows us to assess the effects of bailout expectations on both the structural component of health expenditure and its deviations from the ‘best practice’. The evidence from the 15 Italian ordinary statute regions (observed from 1993 to 2006) points out that bailout expectations do not significantly influence the position of the frontier, thus not affecting citizens' health. However, they do appear to exert a remarkable impact on excess spending. Copyright © 2013 John Wiley & Sons, Ltd.
Measurement of stream cross section using ground penetration radar with Hilbert–Huang transform
Authors: Chen Yen‐Chang , Kao Su‐Pai , Wu Jhong‐Hua
Published: February 2013

This study presents a new method to measure stream cross section without having contact with water. Compared with conventional measurement methods which apply instruments such as sounding weight, ground penetration radar (GPR), used in this study, is a non‐contact measurement method. This non‐contact measurement method can reduce the risk to hydrologists when they are conducting measurements, particularly in high flow period. However, the original signals obtained by using GPR are very complex, different from studies in the past where the measured data were mostly interpreted by experts with special skill or knowledge of GPR so that the results obtained were less objective. This study employs Hilbert–Huang transform (HHT) to process GPR signals which are difficult to interpret by hydrologists. HHT is a newly developed signal processing method that can not only process the nonlinear and non‐stationary complex signals, but also maintain the physical significance of the signal itself. Using GPR with HHT, this study establishes a non‐contact stream cross‐section measurement method with the ability to measure stream cross‐sectional areas precisely and quickly. Also, in comparison with the conventional method, no significant difference in results is found to exist between the two methods, but the new method can considerably reduce risk, measurement time, and manpower. It is proven that the non‐contact method combining GPR with HHT is applicable to quickly and accurately measure stream cross section. Copyright © 2013 John Wiley & Sons, Ltd.
LONGITUDINAL AND CONCURRENT PATHWAYS TO ALCOHOLISM: THE IMPORTANCE OF PERCEPTION OF NEIGHBORHOOD DISORDER
Authors: Martin‐Storey Alexa , Ruttle Paula L. , Temcheff Caroline E. , Serbin Lisa A. , Stack Dale M. , Ledingham Jane E. , Schwartzman Alex E.
Published: February 2013

Neighborhood‐level and individual‐level variables from childhood and adulthood were examined in relation to alcoholism in adulthood. In 1976–1978, children from working‐class neighborhood schools in Montreal, Canada participated in a study examining the outcomes of childhood behaviors. At this time, peer nominations of childhood aggression were collected. In 1999–2003, these participants were contacted during mid‐adulthood (N = 676) and asked to complete measures of perception of neighborhood disorder as well as a structured clinical interview assessing their lifetime history of alcoholism. Measures of participants’ neighborhood socioeconomic status (SES) from adolescence and adulthood were retrieved from Canadian census tract data and included in the model. Findings supported an association between neighborhood disorder and alcoholism, such that perceived disorder mediated the association between census‐based assessments of neighborhood SES and alcoholism, but not when examined within a larger model. These findings supported the importance of the individual's interpretation of their environment in relation to alcoholism.
CHILDHOOD TEMPERAMENT‐BASED ANTICIPATORY GUIDANCE IN AN HMO SETTING: A LONGITUDINAL STUDY
Authors: Cameron James R. , Rice David C. , Sparkman Gregg , Neville Helen F.
Published: February 2013

This study investigates whether individualized, anticipatory temperament guidance could benefit the parent‐child relationship and improve children's mental health over time. Parents of preschoolers in a health management organization completed a temperament questionnaire, received written parenting information tailored to their child's temperament, and were asked to complete a program evaluation questionnaire. The numbers of subsequent visits to the pediatric and psychiatry departments with anxiety, depression, attention deficit hyperactivity disorder, and other externalizing behavior diagnoses were compared over 15 years to a control sample that received only standard care. Parents positively reviewed the program and boys who received the intervention had fewer visits with psychiatric diagnoses. Analyses revealed an interaction effect, where boys with harder‐to‐manage temperaments saw a greater reduction in visits from the intervention. By sensitizing parents to their child's temperament and helping parents understand and manage temperament‐related behaviors, anticipatory guidance can encourage a positive parent‐child relationship and reduce future occurrences of psychiatric diagnoses.
CALCULI OF COMPLEXITY: HOW PHENOMENA EMERGE FROM RULES
Authors: McDowell J. J
Published: February 2013

A complex system is one that generates emergent structures, usually by the repeated application of relatively simple rules. The structures are emergent in the sense that they are not specified in, and cannot be predicted from, the rules that produce them. Mitchell argues for a unified science of complexity but does not ultimately succeed in providing a coherent account. Her book is nevertheless useful as an introduction to some systems and algorithms that have been studied in complexity research and that may be applicable to natural phenomena, including the behavior of organisms. The book also contains interesting historical and biographical details about complexity research and some of the mathematicians and scientists who have contributed to it. A sample of the specific complex systems and algorithms Mitchell introduces is examined in this review, including iterated maps, cellular automata, genetic algorithms, and small world and random Boolean networks. The relevance of complexity theory for behavior analysis is also considered, including applications of simple rules, networks, cellular automata, and genetic algorithms.
EVIDENCE FOR RESPONSE MEMBERSHIP IN STIMULUS CLASSES BY PIGEONS
Authors: Urcuioli Peter J. , Jones B. Max , Lionello‐DeNolf Karen M.
Published: February 2013

Response membership in pigeons' stimulus‐class formation was evaluated using associative symmetry and class expansion tests. In Experiment 1, pigeons learned hue–hue (AA) and form–form (BB) successive matching plus a modified hue–form (AB) task in which reinforcement was contingent upon a left versus right side‐key response after the positive AB sequences. On subsequent BA (symmetry) probe trials, pigeons responded more often to the comparisons on the reverse of the positive than negative AB sequences and, more importantly, preferentially pecked the side key consistent with symmetry after the reversed positive sequences. In Experiment 2, the original three baseline tasks were supplemented by dot–white (CC) successive matching in which reinforcement was contingent upon a left versus right side‐key response after the positive CC sequences. Class expansion was then tested by presenting nonreinforced CA and CB successive matching probes. Comparison response rates were mostly nondifferential on CA probes but were uniformly higher on CB probes that consisted of the C samples and B comparisons from the same, hypothesized class. Together, these results provide evidence that responses can become members of stimulus classes, as predicted by Urcuioli's (2008) theory of pigeons' stimulus‐class formation and Sidman's (2000) theory of equivalence.
High‐performance doubly fed induction machine drive system using predictive direct torque control drive system fed by indirect matrix converters
Authors: Behnia Hamid , Faraji Vahid , Aghasi Majid , Arab Khaburi Davood
Published: February 2013

This paper presents a novel predictive direct torque control for doubly fed induction machine based on indirect matrix converter (IMC), which is characterized by its simple structure, minimal‐torque ripple, and constant switching frequency. Nowadays, the control strategies based on predictive methods have proved their efficiency to improve drive systems capabilities. So, in this paper, one of the best predictive methods that have recently been suggested for doubly fed induction machine drive systems is applied to IMC. The purpose of this combination is to modify the control parameters and size/volume reduction of drive system structure, which is difficult to achieve in conventional systems based on voltage source inverters. The good tracking behavior with reduced torque and flux ripple for both motoring and generating modes as well as removing bulky electrolytic capacitor from the DC link of a converter resulted by using three vectors, two active vectors together with one zero vector per switching period, and applying these vectors to the inverter stage of IMC. To improve the motor drive system performance and reduce losses caused by snubber circuits, the rectifier four‐step commutation method in rectifier bridge is used. In the inverter stage, the predictive direct torque control method is employed. The simulation results of the proposed model confirm its effectiveness and accuracy. Copyright © 2013 John Wiley & Sons, Ltd.
Generalized optical gain analysis in nonparabolic semiconductor laser
Authors: Dey Anup , Maiti Biswajit , (Sarkar) Debasree Chanda
Published: February 2013

A simple generalized theory is developed for optical gain of nonparabolic semiconductor lasers based on the three‐band model of Kane, by taking into account the wave‐vector () dependence of the optical matrix element. The gain in laser of nonparabolic semiconductors is demonstrated, by taking InAs, InSb, Hg1−xCdxTe and In1−xGaxAsyP1−y lattice matched to InP as examples, and it has been found that the peak of the gain spectra for a given carrier density is higher in the three‐band model of Kane than those with parabolic energy band approximations in all the cases. The difference between the peak of gain spectra for three‐band model and the parabolic band model is greater for laser of narrow band gap materials in comparisons with that of laser of wide band gap materials, thereby reveals the necessity for inclusion of the nonparabolicity in modeling lasers of small band gap materials. The well‐known results for wide band gap materials having parabolic energy bands has also been obtained from our generalized formulation under certain limiting condition. Copyright © 2013 John Wiley & Sons, Ltd.
Topological mapping methods for α‐helical bacterial membrane proteins – an update and a guide
Authors: Islam Salim T. , Lam Joseph S.
Published: February 2013

Integral membrane proteins with α‐helical transmembrane segments (TMS) are known to play important and diverse roles in prokaryotic cell physiology. The net hydrophobicity of TMS directly corresponds to the observed difficulties in expressing and purifying these proteins, let alone producing sufficient yields for structural studies using two‐/three‐dimensional (2D/3D) crystallographic or nuclear magnetic resonance methods. To gain insight into the function of these integral membrane proteins, topological mapping has become an important tool to identify exposed and membrane‐embedded protein domains. This approach has led to the discovery of protein tracts of functional importance and to the proposition of novel mechanistic hypotheses. In this review, we synthesize the various methods available for topological mapping of α‐helical integral membrane proteins to provide investigators with a comprehensive reference for choosing techniques suited to their particular topological queries and available resources.
Short‐term, high fat feeding‐induced changes in white adipose tissue gene expression are highly predictive for long‐term changes
Authors: Voigt Anja , Agnew Katrin , van Schothorst Evert M. , Keijer Jaap , Klaus Susanne
Published: February 2013

Scope

We aimed to evaluate the predictability of short‐term (5 days) changes in epididymal white adipose tissue (eWAT) gene expression for long‐term (12 weeks) changes induced by high‐fat diet (HFD) feeding.

Methods and results

Mice were fed semisynthetic diets containing 10 (low‐fat diet) or 40 (HFD) energy% of fat. Global gene expression in eWAT was analyzed using microarrays and confirmed by quantitative PCR. As expected, HFD feeding resulted in increased body fat accumulation and reduced glucose tolerance after 12 weeks. A total of 4678 transcripts were significantly changed by HFD after 12 weeks and 973 after 5 days, with an overlap of 764 transcripts encoding 549 genes. Of these, 79% were downregulated and 21% were upregulated by HFD, all in the same direction and highly correlated (r2 = 0.90) between the time points. Pathway analysis showed downregulation of the main identified processes: lipid metabolism, carbohydrate metabolism, and oxidative phosphorylation. Mest (mesoderm‐specific transcript) was highly upregulated, confirming its role as an early marker of fat cell expansion.

Conclusion

The high predictive value of short‐term gene expression changes for long‐term effects of high fat feeding is a promising step to establish robust early biomarkers that could shorten animal trials to assess health‐promoting food compounds.
Identification and mitigation of interference sources present in SSB‐based wireless MRI receiver arrays
Authors: Riffe Matthew J. , Twieg Michael D. , Gudino Natalia , Blumenthal Colin J. , Heilman Jeremiah A. , Griswold Mark A.
Published: February 2013

Purpose

Single sideband amplitude modulation (SSB) is an appealing platform for highly parallel wireless MRI detector arrays because the spacing between channels is ideally limited only by the MRI signal bandwidth. However this assumes that no other sources of interference are present outside that bandwidth. This work investigates the practical interference between multiple SSB‐encoded MRI signals.

Methods

Noise from coil preamplifiers and carrier bleed‐through are identified as sources of interference. Two different SSB systems were designed for 1.5 T with different noise filtering properties. We show how the differences between the filtered noise profiles impact the received MR signal's dynamic range (DRsig) and image signal‐to‐noise ratio through simulation, bench measurements, and phantom imaging experiments.

Results

When operating individually in the MR scanner, both SSB systems were shown to minimally impact the original DRsig and signal‐to‐noise ratio. Conversely, when all eight channels were operating simultaneously, an average signal‐to‐noise ratio loss was observed to be 12% in the one system, while a second system with more complex filtering was able to achieve a 3% loss in signal‐to‐noise ratio.

Conclusion

Successful wireless transmission of multiple SSB‐encoded MRI signals is possible as long as channel interference is properly managed through design and simulation. Magn Reson Med 70:1775–1786, 2013. © 2013 Wiley Periodicals, Inc.
Inverse‐motion‐based form finding for quasi‐incompressible finite electroelasticity
Authors: Ask Anna , Denzer Ralf , Menzel Andreas , Ristinmaa Matti
Published: February 2013

This work deals with inverse‐motion‐based form finding for electroelasticity. The inverse motion problem is formulated for the electroelastic case, and the resulting equations are implemented within a finite element framework. A four‐field variational approach is adopted, taking into consideration the typically incompressible behavior of the elastomer materials commonly used in electromechanical applications. By means of numerical simulations, the inverse‐motion‐based form finding makes it possible to design the referential configuration so that a given set of loads and boundary conditions results in a prespecified deformed configuration. The computational finite element framework established in this work allows for such numerical simulations and testing and thereby the possibility to improve the design and accuracy in electroelastic applications such as grippers, sensors, and seals. Copyright © 2013 John Wiley & Sons, Ltd.
The obesity epidemic and changes in self‐report biases in BMI
Authors: Hattori Aiko , Sturm Roland
Published: February 2013

Objective:

To assess time trends in measurement error of BMI and the sensitivity/specificity of classifying weight status in the United States by analyzing the difference in BMI between self‐reported and measured height and weight.

Design and Methods:

Data from 18,394 respondents aged 20‐89 years from the National Health and Nutrition Examination Survey (NHANES) from 1999 through 2008 were analyzed. Multiple linear regression and logistic regression models estimated trends in reporting bias and misclassification of weight status by BMI categories, sex, age, and racial/ethnic groups, adjusting for the sampling design.

Results:

We find no evidence that there are time trends in the accuracy of self‐report by BMI categories, sex, age, or racial/ethnic groups. The well‐known downward bias in self‐report has remained stable over the last decade; approximately one in six to seven obese individuals were misclassified as nonobese due to underestimation of BMI.

Conclusion:

Increases in obesity rates based on self‐reported height and weight are likely to reflect actual weight increases and are not inflated by changes in reporting accuracy.
Intrahepatic lipid, not visceral or muscle fat, is correlated with insulin resistance in older, female rhesus macaques
Authors: Chu Michael P. , Klopfenstein Bethany J. , Krisky Christine M. , Urbanski Henryk F. , Rooney William D. , Kohama Steven G. , Purnell Jonathan Q.
Published: February 2013

Objective

Little is known of the effect of body composition on glucose metabolism in the aging female non‐human primate. These variables in older female Rhesus macaques were studied.

Design and Methods

Female Rhesus macaques (Macaca mulatta, n = 19, age range 23‐30 years) underwent magnetic resonance imaging and 1H spectroscopy to quantify total abdominal fat, visceral fat (VF), subcutaneous fat (SF) area, extramyocellular lipid (EMCL), intramyocellular lipid (IMCL) and intrahepatic lipid (IHL) content, and DEXA scan for whole body composition. A subgroup (n = 12) underwent a fasting blood draw and intravenous glucose tolerance test.

Results

SF correlated with homeostatic model assessment of insulin resistance (HOMAIR) and quantitative insulin sensitivity check index (QUICKI), but not after adjustment for fat mass. IHL demonstrated the strongest correlation with HOMAIR, QUICKI and calculated insulin sensitivity index (CSI), and remained significant after adjustment for fat mass. VF, IMCL, and EMCL did not correlate with any of our measures of insulin sensitivity.

Conclusions

Despite a greater amount of VF compared to SF, VF was not associated with markers of insulin resistance (IR) in the older female monkey. Instead, IHL is a marker for IR in the fasting and post‐prandial state in these animals.
The influence of weight gain patterns in pregnancy on fetal growth using cluster analysis in an obese and nonobese population
Authors: Galjaard S. , Pexsters A. , Devlieger R. , Guelinckx I. , Abdallah Y. , Lewis C. , van Calster B. , Bourne T. , Timmerman D. , Luts J.
Published: February 2013

Objective

Excessive weight gain during pregnancy has an important influence on fetal growth and on weight development in future generations.

Design and Methods

A prospective cohort study of 325 obese and nonobese Caucasian women with naturally conceived, singleton pregnancies was performed. They were followed up until delivery for maternal weight gain and for fetal growth with ultrasound‐based weight estimations and final birth weight. Using cluster analysis distinct profiles of maternal weight gain during pregnancy were obtained. Longitudinal regression analysis was performed to investigate the relationship of the maternal weight gain profile and BMI on fetal growth and final birth weight.

Results

Cluster analysis revealed four discernable maternal weight gain profiles: 12 cases (3.7%) ended up at their starting weight or decreased in weight (cluster 1), 16 cases (4.9%) who slightly increased in weight (maximum 4 kg) as compared to their initial weight (cluster 2), 114 cases (35.1%) who gained between 4 and 12 kg in weight (cluster 3), and 183 cases (56.3%) who showed the largest weight gain: more than 12 kg (cluster 4). There were statistically significant differences in fetal growth associated with weight gain cluster, which became apparent late in the second trimester and increased toward the end of pregnancy. Maternal BMI and maternal weight gain profile were independent predictors of fetal growth and birth weight.

Conclusions

Therefore, the conclusion is that the cluster analysis permits to discern four gestational weight gain (GWG) patterns in obese and nonobese subjects and that both maternal BMI and maternal weight gain pattern during pregnancy positively influence fetal growth and birth weight.
Effects of risperidone on energy balance in female C57BL/6J mice
Authors: Li Xingsheng , Johnson Maria S. , Smith Daniel L. , Li Yan , Kesterson Robert A. , Allison David B. , Nagy Tim R.
Published: February 2013

Objective

To investigate the effect of risperidone on energy expenditure and weight gain in female C57BL/6J mice.

Design and Methods

Body weight and composition, food intake, energy expenditure, and activity were determined weekly. mRNA expression of uncoupling protein 1 in brown adipose tissue, orexin, and brain‐derived neurotrophic factor in the hypothalamus were quantified using real‐time PCR.

Results

Risperidone tended to induce a greater body weight gain (P = 0.052) and significantly higher food intake (P = 0.038) relative to the placebo‐treated group. Risperidone‐treated mice had a higher resting energy expenditure (P = 0.001) and total energy expenditure (TEE) (P = 0.005) than the placebo group. There were no effects of treatment, time, and treatment by time on non‐resting (or activity‐related) energy expenditure between groups. Risperidone‐treated mice showed a significantly lesser locomotor activity than placebo‐treated mice over 3 weeks (P < 0.001). Risperidone induced a higher UCP1 mRNA (P = 0.003) and a lower orexin mRNA (P = 0.001) than placebo.

Conclusion

Risperidone‐induced weight gain is associated with hyperphagia and a reduction in locomotor activity in C57BL/6J mice. Additionally, higher total and resting energy expenditure were accompanied by higher levels of UCP1 mRNA in BAT. The increased TEE could not offset the total intake of energy through risperidone‐induced hyperphagia, therefore resulting in weight gain in female C57BL/6J mice.
Municipal Rebate Programs for Environmental Retrofits: An Evaluation of Additionality and Cost‐Effectiveness
Authors: Bennear Lori S. , Lee Jonathan M. , Taylor Laura O.
Published: February 2013

When policies incentivize voluntary activities that also take place in the absence of the incentive, it is critical to identify the additionality of the policy—that is, the degree to which the policy results in actions that would not have occurred otherwise. Rebate programs have become a common conservation policy tool for local municipalities seeking to retrofit residential properties with efficient appliances. This research evaluates whether such rebates can be cost‐effective means for water utilities to promote water conservation. A unique database is developed that combines water‐use data over a three‐year period for all households that participated in a utility's high‐efficiency toilet (HET) rebate program, water‐use data for a matched sample of neighbors who did not receive a rebate, and a survey of rebate participants. Difference‐in‐differences models indicate that installation of an HET reduces household water consumption by approximately 7 percent. While installation of an HET appears to be an effective means for achieving household reductions in water consumption, our results also suggest that the rebate program is a much less effective means for achieving household reductions in water consumption. Specifically, the rebate program is found to provide limited additional water savings beyond what would have occurred naturally and is responsible for only 37 percent of the total water reduction attributable to the installation of HETs over the study period. © 2013 by the Association for Public Policy Analysis and Management.
Changing attitudes towards termination of pregnancy for trisomy 21 with non‐invasive prenatal trisomy testing: a population‐based study in Dutch pregnant women
Authors: Verweij E. J. (Joanne) , Oepkes Dick , de Boer Marjon A.
Published: February 2013

What's already known about this topic?

Decision‐making in prenatal screening involves preparing for the potential diagnosis of Down syndrome (trisomy 21 or T21) and the choice for termination of pregnancy (TOP).

What does this study add?

The results suggest that implementing non‐invasive prenatal testing may be associated with an increased uptake of prenatal testing, whereas the percentage of women who opt to terminate a pregnancy affected by trisomy 21(T21) may likely decrease.

Non‐invasive prenatal testing may not lead to a vast reduction in live births of children with T21, but unlike the current situation, most will be born in families who accepted, with or without testing, the chance of having and caring for a child with T21.
Dispersion of graphene nanoplatelets in poly(vinyl acetate) latex and effect on adhesive bond strength
Authors: Pinto Artur M , Martins Jorge , Moreira J. Agostinho , Mendes Adélio M. , Magalhães Fernão D.
Published: February 2013

Graphene nanoplatelets (GNPs) were directly dispersed in poly(vinyl acetate) (PVAc) latex in concentrations from 0.05 up to 2 wt% (based on dry weight), without using additional surfactants or dispersants. Stable dispersions were obtained due to interaction of the GNPs with protective colloids (poly(vinyl alcohol) and hydroxyethylcellulose) originally present in the latex. This caused an increase in viscosity and accentuated the pseudoplastic behavior of the latex, as evidenced by rheological measurements. Cryo‐SEM imaging showed that individual nanoplatelets were present in the aqueous phase. The equilibrium contact angle for water on dry PVAc films increased by 13° upon incorporation of 0.1 wt% GNPs due to the nanofiller hydrophobicity. However, this increase was lower for higher loadings, probably due to the occurrence of GNP agglomeration. Bond strength measurements performed with an automated bonding evaluation system setup on veneer lap joints showed more than 50% shear strength increase with incorporation of only 0.1–0.3 wt% GNPs. At higher loadings the bond strength decreased, indicating less efficient nanofiller dispersion in the polymer matrix. Raman spectroscopy analysis confirmed that GNP agglomeration was more significant at higher loadings.
Grazing‐incidence transmission small angle X‐ray scattering from thin films of block copolymers
Authors: Mahadevapuram Nikhila , Strzalka Joseph , Stein Gila E.
Published: February 2013

Thin films of lamellar and cylindrical block copolymers are popular systems for low‐cost nanolithography. To be useful as nanoscale templates, the lamellae or cylinders must be oriented perpendicular to the substrate. Domain orientations are usually characterized by microscopy measurements of the film surface, but these techniques cannot detect tilted, bent, or tortuous domains in the film interior. We report a simple method to quantify out‐of‐plane disorder in thin films of block copolymers based on a variant of grazing‐incidence small angle X‐ray scattering (GI‐SAXS). A typical GI‐SAXS experiment illuminates the center of a substrate‐supported film at a grazing angle of incidence (near the film/substrate critical angle), and the strong reflected signal is interpreted with the distorted‐wave Born approximation. In a new approach, the beam footprint is moved to the far edge of the sample, allowing the acquisition of a transmission pattern. The grazing‐incidence transmission data are interpreted with the simple Born approximation, and out‐of‐plane defects are quantified through analysis of crystal truncation rods and partial Debye‐Scherrer rings. Significantly, this study demonstrates that grazing‐incidence transmission small angle X‐ray scattering can detect and quantify the buried defect structure in thin films of block copolymers. © 2013 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013
Computational design, construction, and characterization of a set of specificity determining residues in protein–protein interactions
Authors: Nagao Chioko , Izako Nozomi , Soga Shinji , Khan Samia Haseeb , Kawabata Shigeki , Shirai Hiroki , Mizuguchi Kenji
Published: February 2013

Proteins interact with different partners to perform different functions and it is important to elucidate the determinants of partner specificity in protein complex formation. Although methods for detecting specificity determining positions have been developed previously, direct experimental evidence for these amino acid residues is scarce, and the lack of information has prevented further computational studies. In this article, we constructed a dataset that is likely to exhibit specificity in protein complex formation, based on available crystal structures and several intuitive ideas about interaction profiles and functional subclasses. We then defined a “structure‐based specificity determining position (sbSDP)” as a set of equivalent residues in a protein family showing a large variation in their interaction energy with different partners. We investigated sequence and structural features of sbSDPs and demonstrated that their amino acid propensities significantly differed from those of other interacting residues and that the importance of many of these residues for determining specificity had been verified experimentally. Proteins 2012;. © 2012 Wiley Periodicals, Inc.
Electrostatic interactions play an essential role in the binding of oleic acid with α‐lactalbumin in the HAMLET‐like complex: A study using charge‐specific chemical modifications
Authors: Xie Yongjing , Min Soyoung , Harte Níal P. , Kirk Hannah , O'Brien John E. , Voorheis H. Paul , Svanborg Catharina , Hun Mok K.
Published: February 2013

Human α‐lactalbumin made lethal to tumor cells (HAMLET) and its analogs are partially unfolded protein‐oleic acid (OA) complexes that exhibit selective tumoricidal activity normally absent in the native protein itself. To understand the nature of the interaction between protein and OA moieties, charge‐specific chemical modifications of lysine side chains involving citraconylation, acetylation, and guanidination were employed and the biophysical and biological properties were probed. Upon converting the original positively‐charged lysine residues to negatively‐charged citraconyl or neutral acetyl groups, the binding of OA to protein was eliminated, as were any cytotoxic activities towards osteosarcoma cells. Retention of the positive charges by converting lysine residues to homoarginine groups (guanidination); however, yielded unchanged binding of OA to protein and identical tumoricidal activity to that displayed by the wild‐type α‐lactalbumin‐oleic acid complex. With the addition of OA, the wild‐type and guanidinated α‐lactalbumin proteins underwent substantial conformational changes, such as partial unfolding, loss of tertiary structure, but retention of secondary structure. In contrast, no significant conformational changes were observed in the citraconylated and acetylated α‐lactalbumins, most likely because of the absence of OA binding. These results suggest that electrostatic interactions between the positively‐charged basic groups on α‐lactalbumin and the negatively‐charged carboxylate groups on OA molecules play an essential role in the binding of OA to α‐lactalbumin and that these interactions appear to be as important as hydrophobic interactions. Proteins 2013. © 2012 Wiley Periodicals, Inc.
Nucleotide recognition by the initiation factor aIF5B: Free energy simulations of a neoclassical GTPase
Authors: Simonson Thomas , Satpati Priyadarshi
Published: February 2013

The GTPase aIF5B is a universally conserved initiation factor that assists ribosome assembly. Crystal structures of its nucleotide complexes, X‐ray(GTP) and X‐ray(GDP), are similar in the nucleotide vicinity, but differ in the orientation of a distant domain IV. This has led to two, contradictory, mechanistic models. One postulates that X‐ray(GTP) and X‐ray(GDP) are, respectively, the active, “ON” and the inactive, “OFF” states; the other postulates that both structures are OFF, whereas the ON state is still uncharacterized. We study GTP/GDP binding using molecular dynamics and a continuum electrostatic free energy method. We predict that X‐ray(GTP) has a ≈ 3 kcal/mol preference to bind GDP, apparently contradicting its assignment as ON. However, the preference arises mainly from a single, nearby residue from the switch 2 motif: Glu81, which becomes protonated upon GTP binding, with a free energy cost of about 4 kcal/mol. We then propose a different model, where Glu81 protonation/deprotonation defines the ON/OFF states. With this model, the X‐ray(GTP):GTP complex, with its protonated Glu81, is ON, whereas X‐ray(GTP):GDP is OFF. The model postulates that distant conformational changes such as domain IV rotation are “uncoupled” from GTP/GDP exchange and do not affect the relative GTP/GDP binding affinities. We analyze the model using a general thermodynamic framework for GTPases. It yields rather precise predictions for the nucleotide specificities of each state, and the state specificities of each nucleotide, which are roughly comparable to the homologues IF2 and aIF2, despite the lack of any conformational switching in the model. © 2012 Wiley Periodicals, Inc.