bluuebunny/crossref_metadata_2025_split huggingface dataset:
A framework for the evaluation of ground motion selection and modification procedures
Authors: Kwong N. Simon , Chopra Anil K. , McGuire Robin K. 
Published: October 2014

SummaryThis study develops a framework to evaluate ground motion selection and modification (GMSM) procedures. The context is probabilistic seismic demand analysis, where response history analyses of a given structure, using ground motions determined by a GMSM procedure, are performed in order to estimate the seismic demand hazard curve (SDHC) for the structure at a given site. Currently, a GMSM procedure is evaluated in this context by comparing several resulting estimates of the SDHC, each derived from a different definition of the conditioning intensity measure (IM). Using a simple case study, we demonstrate that conclusions from such an approach are not always definitive; therefore, an alternative approach is desirable. In the alternative proposed herein, all estimates of the SDHC from GMSM procedures are compared against a benchmark SDHC, under a common set of ground motion information. This benchmark SDHC is determined by incorporating a prediction model for the seismic demand into the probabilistic seismic hazard analysis calculations. To develop an understanding of why one GMSM procedure may provide more accurate estimates of the SDHC than another procedure, we identify the role of ‘IM sufficiency’ in the relationship between (i) bias in the SDHC estimate and (ii) ‘hazard consistency’ of the corresponding ground motions obtained from a GMSM procedure. Finally, we provide examples of how misleading conclusions may potentially be obtained from erroneous implementations of the proposed framework. Copyright © 2014 John Wiley & Sons, Ltd.
Designing interference‐aware network selection protocol for WLAN mobile devices
Authors: Kim Hyunsoon , Kim Hwangnam 
Published: October 2014

AbstractDue to increasing demand of wireless services for portable devices, numerous efforts to enhance wireless network performance have been made for decades. Many researchers were focused on the word ‘seamless’ for sustaining connectivity during a handover process, but wireless performance of destined access point (AP) is rarely considered. This paper analyses thoroughly usual network connection behaviour, captures several problems from the procedure, and proposes interference‐avoiding selection (IAS) mechanism that associates a wireless AP, which is expected to perform better than other APs nearby. Proposed selection mechanism concentrates on utilization of each channel within one hop range and received signal strength measured by incoming beacons from surrounding APs. Possible interference by adjacent channels is also considered in this paper. Moreover, unlike any other prior selection mechanism, IAS protocol does not require any modification on existing communication protocols, extra delay to evaluate surrounding APs, and support from huge data server that collects information and derives quality of surrounding APs ahead of the selection phase. Various analysis and performance evaluations are progressed using OPNET, ns2, and Android programming, and the evaluation results showed that proposed selection mechanism can increase the throughput of original selection mechanism by more than 55% in average. Copyright © 2014 John Wiley & Sons, Ltd.
Statistical modeling of time‐dependent fMRI activation effects
Authors: Kalus Stefanie , Bothmann Ludwig , Yassouridis Christina , Czisch Michael , Sämann Philipp G. , Fahrmeir Ludwig 
Published: October 2014

AbstractFunctional magnetic resonance imaging (fMRI) activation detection within stimulus‐based experimental paradigms is conventionally based on the assumption that activation effects remain constant over time. This assumption neglects the fact that the strength of activation may vary, for example, due to habituation processes or changing attention. Neither the functional form of time variation can be retrieved nor short‐lasting effects can be detected by conventional methods. In this work, a new dynamic approach is proposed that allows to estimate time‐varying effect profiles and hemodynamic response functions in event‐related fMRI paradigms. To this end, we incorporate the time‐varying coefficient methodology into the fMRI general regression framework. Inference is based on a voxelwise penalized least squares procedure. We assess the strength of activation and corresponding time variation on the basis of pointwise confidence intervals on a voxel level. Additionally, spatial clusters of effect curves are presented. Results of the analysis of an active oddball experiment show that activation effects deviating from a constant trend coexist with time‐varying effects that exhibit different types of shapes, such as linear, (inversely) U‐shaped or fluctuating forms. In a comparison to conventional approaches, like classical SPM, we observe that time‐constant methods are rather insensitive to detect temporary effects, because these do not emerge when aggregated across the entire experiment. Hence, it is recommended to base activation detection analyses not merely on time‐constant procedures but to include flexible time‐varying effects that harbour valuable information on individual response patterns. Hum Brain Mapp 36:731–743, 2015. © 2014 Wiley Periodicals, Inc.
The DTI connectivity of the human claustrum
Authors: Torgerson Carinna M. , Irimia Andrei , Goh S. Y. Matthew , Van Horn John Darrell 
Published: October 2014

AbstractThe origin, structure, and function of the claustrum, as well as its role in neural computation, have remained a mystery since its discovery in the 17th century. Assessing the in vivo connectivity of the claustrum may bring forth useful insights with relevance to model the overall functionality of the claustrum itself. Using structural and diffusion tensor neuroimaging in N = 100 healthy subjects, we found that the claustrum has the highest connectivity in the brain by regional volume. Network theoretical analyses revealed that (a) the claustrum is a primary contributor to global brain network architecture, and that (b) significant connectivity dependencies exist between the claustrum, frontal lobe, and cingulate regions. These results illustrate that the claustrum is ideally located within the human central nervous system (CNS) connectome to serve as the putative “gate keeper” of neural information for consciousness awareness. Our findings support and underscore prior theoretical contributions about the involvement of the claustrum in higher cognitive function and its relevance in devastating neurological disease. Hum Brain Mapp 36:827–838, 2015. © 2014 Wiley Periodicals, Inc.
Abdominal wall thickness is not useful to predict appendix visualization on sonography in adult patients with suspected appendicitis
Authors: Koseekriniramol Vasan , Kaewlai Rathachai 
Published: October 2014

ABSTRACTPurposeTo evaluate clinical and imaging factors for potential use in predicting appendix visualization on sonography (US) of adult patients with suspected appendicitis.MethodsAll adult patients who underwent appendiceal US from January through June 2010 were included in this retrospective study. Clinicopathological records were reviewed for age, sex, weight, body mass index, symptom duration, Alvarado score, surgicopathologic diagnosis, and disposition. Imaging records were collated for abdominal thicknesses, appendix visualization, and impression. The definitive diagnosis was made on pathologic evaluation.ResultsEighty‐six patients (68 women; median age, 35.5 years; age range, 16–86 years) met the inclusion criteria. The patients' mean weight was 56 kg; body mass index, 22.4; duration of symptoms, 24 hours; and Alvarado score, 6.5. Of the 86 patients, 37 (43%) had appendicitis. The appendix was visualized on US in 27 patients, of whom 25 had appendicitis; the appendix was not visualized in 59 patients, of whom 12 had appendicitis. There was no correlation between the clinical factors studied, the abdominal fat thickness (10.9 versus 10.7 mm; p = 0.90), or the abdominal wall thickness (16.9 versus 17.3 mm; p = 0.76) between patients with a US‐visualized appendix and those whose appendix was not visualized on US.ConclusionsAbdominal thicknesses and other factors are not predictive of appendix visualization on US examination of adults with suspected appendicitis. © 2014 Wiley Periodicals, Inc. J Clin Ultrasound 43:269–276, 2015
Predictors of therapy failure in a series of 741 adult pyogenic liver abscesses
Authors: Lo Joseph Zhi Wen , Leow Jeffrey Jia Jun , Ng Perryn Ling Fei , Lee Hui Qi , Mohd Noor Nor Alia , Low Jee Keem , Junnarkar Sameer P. , Woon Winston Wei Liang 
Published: October 2014

AbstractBackgroundAdult pyogenic liver abscess (PLA) is a major hepato‐biliary infection. We aim to identify risk factors associated with therapy failure.MethodsRetrospective study of 741 PLA patients (2001–2011) and comparison with earlier data (1994–1997). Risk factors associated with therapy failure were identified with multivariate analysis.ResultsIncidence of PLA is 86/100 000 admissions, with average size 5.75 cm. 68% of PLA were secondary to Klebsiella pneumoniae and there is increasing extended‐spectrum beta‐lactamase (ESBL) resistance. Compared with 1990s, there is an increasing annual incidence (from 18 to 67). Elderly age (≥55‐years‐old), presence of multiple abscesses, malignancy as etiology and patients who underwent endoscopic intervention are independent predictors for failure of antibiotics‐only therapy while average intravenous antibiotics duration and average abscess size are not. ECOG performance status ≥2, pre‐existing hypertension and hyperbilirubinaemia are independent predictors for failure of percutaneous therapy while the presence of multiple abscesses and average abscess size are not.ConclusionThere is an increasing PLA incidence with increasing ESBL resistance. Percutaneous drainage should be considered early for elderly patients (≥55‐years‐old), with multiple abscesses, malignancy as etiology or who required endoscopic intervention. We should have a low threshold for surgical intervention for patients with ECOG performance status ≥2, co‐morbidity of hypertension or hyperbilirubinaemia.
Poor outcomes after hepatectomy in patients with ascites infected by methicillin‐resistant staphylococci
Authors: Nitta Hidetoshi , Beppu Toru , Itoyama Akari , Higashi Takaaki , Sakamoto Keita , Nakagawa Shigeki , Mima Kosuke , Okabe Hirohisa , Imai Katsunori , Hayashi Hiromitsu , Hashimoto Daisuke , Chikamoto Akira , Ishiko Takatoshi , Baba Hideo 
Published: October 2014

AbstractBackgroundThis study was designed to investigate the association between infectious ascites, clinical parameters and treatment outcomes after hepatectomy.MethodsOf 891 patients who underwent hepatectomy between 2006 and 2013, 74 who underwent paracentesis for bacterial cultivation of postoperative ascites after hepatectomy were analyzed.ResultsOf the 74 patients, 42 had positive bacterial cultures (positive group) and 32 patients had negative cultures (negative group). Hospital mortality was significantly higher in the positive group than in the negative group [9/42 (21.4%) vs. 2/32 (6.3%); P = 0.035]. Hospital mortality associated with each bacterial strain was as follows: methicillin‐resistant staphylococci (MRS) (5/13, 38.5%), staphylococci (2/11, 18.2%), enterococci (2/12, 16.7%), Enterobacter (0/3, 0%), Klebsiella (0/2, 0%), and others (0/1, 0%). Cox proportional multivariate analysis revealed that MRS infection in ascites was the only risk factor of hospital death (HR = 5.08, P = 0.041) and MRS wound infection was the only risk factor to predict MRS infection in ascites (HR = 5.67, P = 0.015).ConclusionPostoperative MRS infection in postoperative ascites after hepatectomy is a potentially fatal complication; therefore, the prevention of MRS wound infection is critical to decrease postoperative hospital mortality.
Prevalence and predictors of return visits to pediatric emergency departments
Authors: Akenroye Ayobami T. , Thurm Cary W. , Neuman Mark I. , Alpern Elizabeth R. , Srivastava Geetanjali , Spencer Sandra P. , Simon Harold K. , Tejedor‐Sojo Javier , Gosdin Craig H. , Brennan Elizabeth , Gottlieb Laura M. , Gay James C. , McClead Richard E. , Shah Samir S. , Stack Anne M. 
Published: October 2014

OBJECTIVETo determine the rate of return visits to pediatric emergency departments (EDs) and identify patient‐ and visit‐level factors associated with return visits and hospitalization upon return.DESIGN AND SETTINGRetrospective cohort study of visits to 23 pediatric EDs in 2012 using data from the Pediatric Health Information System.PARTICIPANTSPatients <18 years old discharged following an ED visit.MEASURESThe primary outcomes were the rate of return visits within 72 hours of discharge from the ED and of return visits within 72 hours resulting in hospitalization. Results: 1,415,721 of the 1,610,201 ED visits to study hospitals resulted in discharge. Of the discharges, 47,294 patients (3.3%) had a return visit. Of these revisits, 9295 (19.7%) resulted in hospitalization. In multivariate analyses, the odds of having a revisit were higher for patients with a chronic condition (odds ratio [OR]: 1.91, 95% confidence interval [CI]: 1.86‐1.96), higher severity scores (OR: 1.42, 95% CI: 1.40‐1.45), and age <1 year (OR: 1.32, 95% CI: 1.22‐1.42). The odds of hospitalization on return were higher for patients with higher severity (OR: 3.42, 95% CI: 3.23‐3.62), chronic conditions (OR: 2.92, 95% CI: 2.75‐3.10), age <1 year (1.7–2.5 times the odds of other age groups), overnight arrival (OR: 1.84, 95% CI: 1.71‐1.97), and private insurance (OR: 1.47, 95% CI: 1.39‐1.56). Sickle cell disease and cancer patients had the highest rates of return at 10.7% and 7.3%, respectively.CONCLUSIONSMultiple patient‐ and visit‐level factors are associated with revisits. These factors may provide insight in how to optimize care and decrease avoidable ED utilization. Journal of Hospital Medicine 2014;9:779–787. © 2014 Society of Hospital Medicine
An assessment of beeswax as a thickener for environmentally friendly lubricating grease production
Authors: Kreivaitis Raimondas , Padgurskas Juozas , Gumbytė Milda , Kupčinskas Artūras 
Published: October 2014

AbstractEnvironmentally friendly lubricants are preferred in many applications where groundwater or soil pollution is possible. The main purpose of the current study was to evaluate the possibility of beeswax use as a thickener for lubricating greases. European beeswax was used as a thickening material for the preparation of lubricating greases. Rapeseed oil and two mineral oils were used as base oils. The consistency, dropping point temperature, and tribological properties of the prepared lubricating greases were investigated and compared with conventional soap‐thickened greases. The prepared greases exhibited good tribological properties, especially the rapeseed‐oil‐based grease. However, tribological properties of conventional lubricating grease were superior to prepared ones. The weakness of the prepared lubricating greases is their narrow working temperature range. However, the beeswax together with rapeseed oil has great potential in the production of environmentally friendly, completely renewable lubricating greases. Copyright © 2014 John Wiley & Sons, Ltd.
7‐Tesla Magnetic Resonance Imaging for Brain Iron Quantification in Homozygous and Heterozygous PANK2 Mutation Carriers
Authors: Dusek Petr , Tovar Martinez Elena Maria , Madai Vince Istvan , Jech Robert , Sobesky Jan , Paul Friedemann , Niendorf Thoralf , Wuerfel Jens , Schneider Susanne A. 
Published: October 2014

AbstractPantothenate‐kinase–associated neurodegeneration (PKAN) is an autosomal recessive disorder characterized by iron deposits in basal ganglia. The aim of this study was to quantify iron concentrations of deep gray matter structures in heterozygous PANK2 mutation carriers and in PKAN patients using quantitative susceptibility mapping MRI. By determining iron concentration, we intended to find mutation‐specific brain parenchymal stigmata in heterozygous PANK2 mutation carriers in comparison to age‐matched healthy volunteers. We studied 11 heterozygous PANK2 gene mutation carriers (mean age: 43.4 years; standard deviation [SD]: 10.5), who were found to be clinically asymptomatic by neurological examination. These carriers were compared to 2 clinically affected PKAN patients 21 and 32 years of age and to 13 age‐matched, healthy controls (mean age: 39.7; SD, 13.6). Scanning was performed on a 7.0‐Tesla whole‐body scanner applying three‐dimensional susceptibility‐weighted gradient echo acquisitions. Susceptibility maps were calculated by threshold‐based k‐space division with single‐orientation acquisition. Magnetic susceptibility values, relative to the occipital white matter, were determined for the following regions of interest (ROI): globus pallidus (GP), thalamus, putamen, internal capsule (IC), caudate nucleus, substantia nigra (SN), and red nucleus. Heterozygous PANK2 mutation carriers did not show increased brain iron concentrations, compared to healthy controls (P > 0.05), in any of the examined ROIs. In PKAN patients, more than 3 times higher concentrations of iron were found in the GP, SN, and IC. Our results suggest that heterozygous mutations in PANK2 gene do not cause brain iron accumulation nor do they cause movement disorders.
Effects of Tyrosine on Parkinson's Disease: A Randomized, Double‐Blind, Placebo‐Controlled Trial
Authors: DiFrancisco‐Donoghue Joanne , Rabin Ely , Lamberg Eric M. , Werner William G. 
Published: October 2014

AbstractIndividuals with Parkinson's disease (PD) can suffer from orthostatic hypotension (OH) resulting from reduced levels of norepinephrine (NE), which inhibits the sympathetic nervous system. Levodopa reduces NE levels even further, leading to a greater decrease in blood pressure (BP) and increased OH. Tyrosine is a nonessential amino acid that is the major precursor to NE. Reduced levels of tyrosine have been shown after administration of l‐dopa. This study was a single‐center, randomized, double‐blind, placebo‐controlled trial to test the effects of supplementing l‐tyrosine on BP, plasma tyrosine, NE levels, and autonomic responses to exercise in PD. Thirty‐six subjects with PD receiving l‐dopa medication that suffer from OH participated. Random assignment was to a placebo group or l‐tyrosine 1,000 mg (500 mg of 2× daily) group for 7 days. OH testing and exercise testing was performed pre‐ and postsupplementation. There was no effect of tyrosine on BP after OH testing postsupplementation (tyrosine, n = 17; placebo, n = 19). There was an increase in plasma tyrosine in the tyrosine group (P > 0.05). There were no significant changes in any of the secondary outcome measures. l‐tyrosine at 1,000 mg (500 mg/2× day) for 7 days is safe and well tolerated in PD. Our results were inconclusive as to whether an increase in plasma tyrosine has an effect on OH in subjects with PD. An increase in plasma tyrosine had no effect on BP or autonomic responses in subjects with PD during acute exercise stress. (Trial registration: ClinicalTrials.gov.; identifier: NCT01676103)
Accounting for evolving pore size distribution in water retention models for compacted clays
Authors: Della Vecchia Gabriele , Dieudonné Anne‐Catherine , Jommi Cristina , Charlier Robert 
Published: October 2014

SummaryWater retention in compacted clays is dominated by multi‐modal pore size distribution which evolves during hydro‐mechanical paths depending on water content and stress history. A description of the evolutionary fabric has been recently introduced in models for water retention, but mostly on a heuristic base. Here, a possible systematic approach to account for evolving pore size distribution is presented, and its implications in models for water retention are discussed. The approach relies on quantitative information derived from mercury intrusion porosimetry data. The information is exploited to introduce physically based evolution laws for the parameters of water retention models. These laws allow tracking simultaneously the evolution of the aggregated fabric and the consequent hydraulic state of compacted clays. The influence of clay microstructure, mechanical constraints and water content changes on the water retention properties is highlighted and quantified from experimental data on different compacted soils with different activity of the clayey fraction. The framework is discussed with reference to a widespread water retention model and validated against experimental data on a Sicilian scaly clay compacted to different dry densities and subjected to a number of hydro‐mechanical paths. Copyright © 2014 John Wiley & Sons, Ltd.
Correlation of gas permeation and free volume in new and used high free volume thin film composite membranes
Authors: Koschine Toenjes , Rätzke Klaus , Faupel Franz , Khan Muntazim Munir , Emmler Thomas , Filiz Volkan , Abetz Volker , Ravelli Luca , Egger Werner 
Published: October 2014

ABSTRACTPolymeric gas separation membranes frequently undergo the phenomenon of aging, that is, performance parameters like permeability decrease with storage or usage time. Here, we report on a new approach of reducing aging by incorporation of functionalized multiwalled carbon nanotubes into a polymer of intrinsic microporosity. Free volume and permeability measurements clearly show a reduced aging with incorporation of the carbon nantubes. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2015, 53, 213–217
Analysis of minimum transmit sum power and scheduling power gain for multi‐user MIMO‐OFDM networks with rate constraints
Authors: Gao Xiangyu , Zhu Yuesheng , Ping Li 
Published: October 2014

ABSTRACTMinimum transmit sum power (MTSP) is of high theoretical and practical value in multi‐user rate‐constrained systems; it is, however, quite difficult to be numerically characterized in complex channels for the prohibitively high computational power required. In this paper, we present a computationally efficient method to approximate the MTSP in multi‐user multiple‐input multiple‐output orthogonal frequency division multiplexing (MU‐MIMO‐OFDM) wireless networks. Specifically, we propose both lower and upper bounds of the MTSP, which are asymptotically accurate in the limit of large K, the number of users. Then, we develop two iterative water‐filling algorithms to numerically solve the proposed bounds. These algorithms are with low complexity, that is, linear in K, and therefore enable the analysis of MTSP in complex channels even if K is large. Numerical results demonstrate the effectiveness of the bounds in approximating the MTSP and the high computational efficiency of the proposed iterative water‐filling algorithms. With the proposed bounds, we further numerically study scheduling power gain (SPG), which is defined as MTSP reduction achieved by scheduling resources over multiple channel blocks in time domain. We simulate the SPG in different wireless environments defined in Third Generation Partnership Project spatial channel extended model and find insignificant SPG in some cases, indicating that the benefit from scheduling over multiple channel blocks is limited and simply allocating resources within the present channel is sufficient. Our analysis on the MTSP and SPG provides guidelines on the design of resource schedulers in MU‐MIMO‐OFDM networks. Copyright © 2014 John Wiley & Sons, Ltd.