bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diagnostic and interventional sialendoscopy: A preliminary experience
Authors: Bowen Matthew A. , Tauzin Marcie , Kluka Evelyn A. , Nuss Daniel W. , DiLeo Michael , McWhorter Andrew J. , Schaitkin Barry , Walvekar Rohan R. 
Published: January 2011

AbstractObjectives/Hypothesis:To review our preliminary experience with diagnostic and therapeutic sialendoscopy for the management of non‐neoplastic disorders of the salivary gland.Study Design:Retrospective chart review.Methods:Thirty‐three consecutive patients undergoing 36 sialendoscopy procedures performed at a tertiary medical center from July 2008 to July 2010 were included.Results:The mean age of presentation was 43 years (range, 7–74 years), and 61% of patients were male. Indications included sialolithiasis (47%; 17 of 36), recurrent sialadenitis (44%, 16 of 36), and Sjo¨︂gren's syndrome (8%; three of 36). Successful endoscopy was performed in 97% (35 of 36). A papillotomy for access was necessary in 25% (nine of 36). In patients with sialolithiasis (n = 17), the mean size of the stones was 7.3 mm (range, 1–20 mm). Complete stone removal was achieved in 76% (13 of 17) of cases. Endoscopic stone removal was possible in 29% (five of 17), and a combined approach technique was required in 47% (eight of 17). Seventy‐two percent (26 of 36) of patients had complete resolution of symptoms after sialendoscopy, with 19% (seven of 36) having partial resolution of symptoms. Patients with partial improvement of symptoms had a mean duration of improvement of 4.7 months. The overall complication rate was 22% (eight of 36). The major and minor complication rates were 3% (one of 36) and 19% (seven of 36), respectively.Conclusions:Sialendoscopy is safe and effective in managing non‐neoplastic salivary gland disorders with low rates of major complications. Knowledge of options to navigate the rate‐limiting steps, like dilation of the papilla and careful case selection, are key to successful outcomes.
Differences in health-related quality of life scores after orthotopic liver transplantation with respect to selected socioeconomic factors
Authors: Saab Sammy , Bownik Hillary , Ayoub Noel , Younossi Zobair , Durazo Francisco , Han Steven , Hong Johnny C. , Farmer Douglas , Busuttil Ronald W. 
Published: January 2011

Abstract
One of the current ultimate goals of orthotopic liver transplantation (OLT) is the improvement of patients' health-related quality of life (HRQOL). The purpose of this study was to look at the effects of socioeconomic and demographic differences on the short-term and long-term HRQOL outcomes of OLT recipients. Three hundred three adult OLT recipients who were seen at the University of California Los Angeles were administered the Medical Outcomes Study Short Form 36 (SF-36), the Chronic Liver Disease Questionnaire (CLDQ), and a demographic survey. A parsimonious model of 12 socioeconomic and demographic predictors was identified. Their simultaneous influence on each SF-36 and CLDQ HRQOL domain score was evaluated with multivariate linear regression and backward selection. Hepatitis C virus impaired HRQOL; this was shown in the SF-36 Vitality and Bodily Pain domains and in most CLDQ domains. Females experienced more HRQOL impairment only within the CLDQ Abdominal Symptoms domain. OLT recipients who were married had better SF-36 Role-Emotion domain scores. OLT recipients with more than 12 years of education had better SF-36 Physical Functioning scores. Employed OLT recipients had less HRQOL impairment; this was evidenced by better scores in multiple domains of the SF-36 and the CLDQ. OLT patients with health maintenance organization or preferred provider organization insurance had higher HRQOL scores within almost all SF-36 and CLDQ domains. Patients with a mix of public and private insurance had significantly higher HRQOL scores in comparison with those with only public insurance. Identifying patients at higher risk for worse HRQOL scores, less satisfaction with OLT results, and greater problems with fatigue or mental health stressors will assist transplant centers in using their medical teams to develop early interventions and multidisciplinary approaches to improve HRQOL outcomes after OLT. Liver Transpl 17:580-590, 2011. © 2011 AASLD.
Critical care of the end-stage liver disease patient awaiting liver transplantation
Authors: Findlay James Y. , Fix Oren K. , Paugam-Burtz Catherine , Liu Linda , Sood Puneet , Tomlanovich Stephen J. , Emond Jean 
Published: January 2011

Abstract
Patients with end-stage liver disease awaiting liver transplantation frequently require intensive care admission and management due to either complications of liver failure or to intercurrent illness, particularly infection. Mortality in such patients is high and the development of an illness necessitating intensive care unit management can influence transplant candidacy. Specialized support frequently requires hemodynamic support, mechanical ventilation, and renal support. In this review, areas of management of particular importance to patients with end-stage liver disease in the intensive care unit are discussed. These areas are hepatic encephalopathy, infectious diseases, cardiovascular support, mechanical ventilation, renal support and combined transplantation, and decisions regarding delisting. Current knowledge specific to these patients, when available, is discussed, current practice is described, and areas of uncertainty in the evidence are discussed. Liver Transpl 17:496-510, 2011. © 2011 AASLD.
PHOENIX
Authors: Bzowej Natalie , Nelson David R. , Terrault Norah A. , Everson Gregory T. , Teng Lichen L. , Prabhakar Avinash , Charlton Michael R. 
Published: January 2011

Abstract
The efficacy, tolerability, and safety of the prophylactic treatment of hepatitis C virus (HCV) after liver transplantation (LT) with peginterferon alfa-2a and ribavirin are not known. LT recipients with HCV were randomized to peginterferon alfa-2a/ribavirin treatment or observation 10 to 26 weeks post-LT. Prophylaxis patients received peginterferon alfa-2a (135 μg/week for 4 weeks and then 180 μg/week for 44 weeks) plus ribavirin (the initial dose of 400 mg/day was escalated to 1200 mg/day). Observation patients received the same regimen only upon significant HCV recurrence (histological activity index ≥ 3 and/or fibrosis score ≥ 2). The primary endpoint was the proportion of patients with histological evidence of significant HCV recurrence 120 weeks after randomization. In all, 115 patients were randomized (prophylaxis arm, n = 55; observation arm, n = 60). Sustained virological response was achieved by 12 of 54 prophylaxis patients (22.2%) and by 3 of 14 observation patients who switched to treatment (21.4%). On an intent-to-treat basis, significant HCV recurrence at 120 weeks was similar in the prophylaxis (61.8%) and observation arms (65.0%, P = 0.725). The patient and graft survival rates and the rates of biopsy-proven acute cellular rejection were similar in the 2 study arms. Approximately 70% of the treated patients in both arms had at least one dose reduction for safety reasons. The most common adverse event leading to treatment withdrawal was anemia. Because of the safety profile of peginterferon alfa-2a/ribavirin and the lack of a clear benefit in terms of HCV recurrence and patient or graft survival, this study does not support the routine use of prophylactic antiviral therapy. Liver Transpl 17:528-538, 2011. © 2011 AASLD.
Progressive parkinsonism, oculomotor abnormalities and autonomic dysfunction: Clinicopathological case
Authors: Fabbrini Giovanni , Merello Marcello , Evans Andrew H. , Lees Andrew J. , Holton Janice , Williams David R. 
Published: January 2011

AbstractA 59‐year‐old woman presented with asymmetric parkinsonism that was not‐responsive to Levodopa therapy. She developed early falls, postural instability, and moderately severe autonomic dysfunction. Eye movement abnormalities were reported 2 years after her first symptoms, and she eventually developed anterocollis. Experts discuss the syndromal diagnosis and predict the underlying pathology. The pathological diagnosis is given and clinical learning points are considered. © 2011 Movement Disorder Society
Prenatal ultrasonographic measurement of the fetal iliac angle during the first and second trimester of pregnancy
Authors: Belics Zoran , Fekete Tibor , Beke Artur , Szabó István 
Published: January 2011

AbstractObjectivesThe aim of this study was to present our results of the sonographic measurement of the fetal iliac angle during the first and second trimesters of pregnancy.MethodsA total of 2168 fetal iliac angle measurements were performed in a transverse section of the fetal pelvis. The iliac angle measurements were compared in fetuses with trisomy 21 (n= 52) and fetuses with normal karyotype (n= 1980). The sensitivity, specificity, positive predictive value, negative predictive value and false positive rate in trisomy 21 fetuses were compared for multiple cut‐off value. Statistical significance for measurements was estimated for trisomy 21.ResultsA total of 2064 fetuses had adequate images for satisfactory measurement of the iliac wing angle and 1831 patients asked for a genetic invasive procedure. Of the fetuses with chromosomal aberrations, only the fetuses with trisomy 21 were included in the investigation. The risk of trisomy 21 in our population was 1 of 39. In the euploid fetuses, the mean iliac wing angle was 63.72°. The mean iliac wing angle in the fetuses with trisomy 21 was 90.32°, significantly higher than those seen in fetuses with normal karyotype.ConclusionThe proven larger iliac wing angle in neonates with Down syndrome can be demonstrated sonographically during the pregnancy, especially in the first and second trimesters. This marker may be useful in prenatal screening or exclusion of trisomy 21. Copyright © 2011 John Wiley & Sons, Ltd.
A Lyapunov controller for stable haptic manipulation of hydraulic actuators
Authors: Zarei‐nia Kurosh , Sepehri Nariman , Wu Qiong 
Published: January 2011

SUMMARYA scheme for bilateral control of hydraulic actuators is developed and experimentally evaluated in this paper. The control laws are derived based on Lyapunov's feedback control design technique. Owing to the discontinuity originating from a sign function in the control laws, the control system is non‐smooth. First, the existence, continuation, and uniqueness of Filippov's solution to the system are proven. Next, the extensions of Lyapunov's stability theory to non‐smooth systems and LaSalle's invariant set theorems are employed to prove the asymptotic stability of the control system. Effectiveness of the proposed controller is verified by simulation and experimental studies. It is shown that beside stability, the system has good transparency in terms of position and force exchanges between the master and slave actuators. Copyright © 2011 John Wiley & Sons, Ltd.
Bounding the bias of unmeasured factors with confounding and effect‐modifying potentials
Authors: Lee Wen‐Chung 
Published: January 2011

AbstractConfounding is a major concern in observational studies. To adjust for confounding bias, the potential confounder(s) for a study must first be identified and measured. But this is not always possible. The unmeasured factors may also exhibit effect modification, and this further complicates the situation. In this paper, the author derives bounding formulas for the bias of unmeasured factors with confounding and effect‐modifying potentials. Based on these formulas, the author derives two conditions (for the unmeasured factors) to explain away an observed positive finding: the low‐threshold (for the minimum of two parameters related to the unmeasured factors) and the high‐threshold (for the maximum) conditions. All these should help researchers make more prudent interpretations of their (potentially biased) results. Copyright © 2011 John Wiley & Sons, Ltd.
On the C‐statistics for evaluating overall adequacy of risk prediction procedures with censored survival data
Authors: Uno Hajime , Cai Tianxi , Pencina Michael J. , D'Agostino Ralph B. , Wei L. J. 
Published: January 2011

AbstractFor modern evidence‐based medicine, a well thought‐out risk scoring system for predicting the occurrence of a clinical event plays an important role in selecting prevention and treatment strategies. Such an index system is often established based on the subject's ‘baseline’ genetic or clinical markers via a working parametric or semi‐parametric model. To evaluate the adequacy of such a system, C‐statistics are routinely used in the medical literature to quantify the capacity of the estimated risk score in discriminating among subjects with different event times. The C‐statistic provides a global assessment of a fitted survival model for the continuous event time rather than focussing on the prediction ofbit‐year survival for a fixed time. When the event time is possibly censored, however, the population parameters corresponding to the commonly used C‐statistics may depend on the study‐specific censoring distribution. In this article, we present a simple C‐statistic without this shortcoming. The new procedure consistently estimates a conventional concordance measure which is free of censoring. We provide a large sample approximation to the distribution of this estimator for making inferences about the concordance measure. Results from numerical studies suggest that the new procedure performs well in finite sample. Copyright © 2011 John Wiley & Sons, Ltd.
Estimating transformations for repeated measures modeling of continuous bounded outcome data
Authors: Hutmacher Matthew M. , French Jonathan L. , Krishnaswami Sriram , Menon Sujatha 
Published: January 2011

AbstractContinuous bounded outcome data are unlikely to meet the usual assumptions for mixed‐effects models of normally distributed and independent subject‐specific and residual random effects. Additionally, overly complicated model structures might be necessary to account adequately for non‐drug (time‐dependent) and drug treatment effects. A transformation strategy with a likelihood component for censoring is developed to promote the simplicity of model structures and to improve the plausibility of assumptions on the random effects. The approach is motivated by Health Assessment Questionnaire Disability Index (HAQ‐DI) data from a study in subjects with rheumatoid arthritis and is evaluated using a simulation study. Copyright © 2011 John Wiley & Sons, Ltd.
Mixture cure model with random effects for clustered interval‐censored survival data
Authors: Xiang Liming , Ma Xiangmei , Yau Kelvin K. W. 
Published: January 2011

AbstractThe mixture cure model is an effective tool for analysis of survival data with a cure fraction. This approach integrates the logistic regression model for the proportion of cured subjects and the survival model (either the Cox proportional hazards or accelerated failure time model) for uncured subjects. Methods based on the mixture cure model have been extensively investigated in the literature for data with exact failure/censoring times. In this paper, we propose a mixture cure modeling procedure for analyzing clustered and interval‐censored survival time data by incorporating random effects in both the logistic regression and PH regression components. Under the generalized linear mixed model framework, we develop the REML estimation for the parameters, as well as an iterative algorithm for estimation of the survival function for interval‐censored data. The estimation procedure is implemented via an EM algorithm. A simulation study is conducted to evaluate the performance of the proposed method in various practical situations. To demonstrate its usefulness, we apply the proposed method to analyze the interval‐censored relapse time data from a smoking cessation study whose subjects were recruited from 51 zip code regions in the southeastern corner of Minnesota. Copyright © 2011 John Wiley & Sons, Ltd.
Mobile anchor assisted particle swarm optimization (PSO) based localization algorithms for wireless sensor networks
Authors: Bao Han , Zhang Baoxian , Li Cheng , Yao Zheng 
Published: January 2011

ABSTRACTNode localization is essential to wireless sensor networks (WSN) and its applications. In this paper, we propose a particle swarm optimization (PSO) based localization algorithm (PLA) for WSNs with one or more mobile anchors. In PLA, each mobile anchor broadcasts beacons periodically, and sensor nodes locate themselves upon the receipt of multiple such messages. PLA does not require anchors to move along an optimized or a pre‐determined path. This property makes it suitable for WSN applications in which data‐collection and network management are undertaken by mobile data sinks with known locations. To the best of our knowledge, this is the first time that PSO is used in range‐free localization in a WSN with mobile anchors. We further derive the upper bound on the localization error using Centroid method and PLA. Simulation results show that PLA can achieve high performance in various scenarios. Copyright © 2011 John Wiley & Sons, Ltd.
The performances study of IEEE 802.11e to support QoS in channel error environment
Authors: Wen Jyh‐Horng , Weng Chien‐Erh 
Published: January 2011

ABSTRACTOne of the most important functions in IEEE 802.11e is enhanced distributed coordination function (EDCF). EDCF is an enhanced version of IEEE 802.11 distributed coordination function (DCF) which provides a priority scheme by differentiating the inter‐frame space and the initial window size. We proposed a modified Markov chain model to study the EDCF priority scheme. We have theoretically analyzed the saturation throughput and delay by using the modified Markov chain model in non‐ideal channel scenario. We also have compared it with the Markov chain model that exists under ideal channel scenario. Simulations are also conducted to validate analytical results. Our study shows that the modified model under ideal channel scenario is better than that in channel error scenario. Copyright © 2011 John Wiley & Sons, Ltd.
Multiuser diversity beamforming for downlink channels using modulation division multiplexing
Authors: Choi Jinho 
Published: January 2011

ABSTRACTMultiuser diversity beamforming (MDB) is investigated for downlink channels of multiuser multiple input multiple output (MIMO) systems. Since the use of multiple beams simultaneously results in a poor performance of MDB when the number of users is not sufficiently large, the use of single‐beam at a time is considered to avoid performance degradation due to the interference from other beams. Furthermore, in order to share a common precoder by multiple users, modulation division multiplexing (MDM) with a higher order modulation for MDB is discussed. Performance criteria for precoder and user selection are derived under the assumption that the maximum likelihood (ML) detector is used. Copyright © 2011 John Wiley & Sons, Ltd.
Beyond computer literacy: Supporting youth's positive development through technology
Authors: Bers Marina Umaschi 
Published: January 2011

AbstractIn a digital era in which technology plays a role in most aspects of a child's life, having the competence and confidence to use computers might be a necessary step, but not a goal in itself. Developing character traits that will serve children to use technology in a safe way to communicate and connect with others, and providing opportunities for children to make a better world through the use of their computational skills, is just as important. The Positive Technological Development framework (PTD), a natural extension of the computer literacy and the technological fluency movements that have influenced the world of educational technology, adds psychosocial, civic, and ethical components to the cognitive ones. PTD examines the developmental tasks of a child growing up in our digital era and provides a model for developing and evaluating technology‐rich youth programs. The explicit goal of PTD programs is to support children in the positive uses of technology to lead more fulfilling lives and make the world a better place. This article introduces the concept of PTD and presents examples of the Zora virtual world program for young people that the author developed following this framework.
YouTube as a participatory culture
Authors: Chau Clement 
Published: January 2011

AbstractThere is an explosion of youth subscriptions to original content‐media‐sharing Web sites such as YouTube. These Web sites combine media production and distribution with social networking features, making them an ideal place to create, connect, collaborate, and circulate. By encouraging youth to become media creators and social networkers, new media platforms such as YouTube offer a participatory culture in which youth can develop, interact, and learn. As youth development researchers, we must be cognizant of this context and critically examine what this platform offers that might be unique to (or redundant of) typical adolescent experiences in other developmental contexts.
Making projects, making friends: Online community as catalyst for interactive media creation
Authors: Brennan Karen , Monroy‐Hernández Andrés , Resnick Mitchel 
Published: January 2011

AbstractTo become full and active participants in today's technologically saturated society, young people need to become creators (and not just consumers) of interactive media. Developing the requisite abilities and capacities is not a wholly individual process; it is important for young people to have access to communities where they can collaborate and share ideas. This article uses the Scratch online community for exploring how different forms of participation and collaboration can support and shape the ways in which young people develop as creators of interactive media. We describe participation in this community in terms of a spectrum ranging from socializing to creating and present examples of three forms of collaboration within the community. We argue that the most exciting interactive media creation and valuable learning experiences are taking place in the middle space, where participants draw on the best of socializing and creating practices.
El Silencio: A rural community of learners and media creators
Authors: Urrea Claudia 
Published: January 2011

AbstractA one‐to‐one learning environment, where each participating student and the teacher use a laptop computer, provides an invaluable opportunity for rethinking learning and studying the ways in which children can program computers and learn to think about their own thinking styles and become epistemologists. This article presents a study done in a rural school in Costa Rica in which students used computers to create media. Three important components of the work are described: (1) student‐owned technology that can accompany students as they interact at home and in the broader community, (2) activities that are designed with sufficient scope to encourage the appropriation of powerful ideas, and (3) teacher engagement in activity design with simultaneous support from a knowledge network of local and international colleagues and mentors.