Read by QxMD icon Read

Simulated practice

N V Lukasheva, D A Tolmachev, V M Nazarychev, J M Kenny, S V Lyulin
Specific intermolecular interactions, in particular H-bonding, have a strong influence on the structural, thermal and relaxation characteristics of polymers. We report here the results of molecular dynamics simulations of Nylon 6 which provides an excellent example for the investigation of such an influence. To demonstrate the effect of proper accounting for H-bonding on bulk polymer properties, the AMBER99sb force field is used with two different parametrization approaches leading to two different sets of partial atomic charges...
December 2, 2016: Soft Matter
Fangfang Tang, Feng Liu, Fabio Freschi, Yu Li, Maurizio Repetto, Luca Giaccone, Yaohui Wang, Stuart Crozier
For head magnetic resonance imaging, local gradient coils are often used to achieve high solution images. To accommodate the human head and shoulder, the head gradient coils are usually designed in an asymmetric configuration, allowing the region-of-uniformity (ROU) close to the coil's patient end. However, the asymmetric configuration leads to technical difficulties in maintaining a high gradient performance for the insertable head coil with very limited space. In this work, we present a practical design configuration of an asymmetric insertable gradient head coil offering an improved performance...
December 21, 2016: Physics in Medicine and Biology
Leigh J Smith, Rachel Kearvell, Anthony J Arnold, Kevina Choma, Aniko Cooper, Michael R Young, Donna L Matthews, Bronwyn Hilder, Debbie Howson, Katherine Fox, Katheryn Churcher
INTRODUCTION: In 2001, the Radiation Therapy Advisory Panel (RTAP) of the Australian Society of Medical Imaging and Radiation Therapy (ASMIRT) (formerly known as Australian Institute of Radiography) published a model for radiation therapist staffing in Australian radiation oncology departments. Between 2012-2013, the model was reviewed to ensure it reflected current radiation therapy practice, technology, and to facilitate forward planning of the radiation therapy workforce. METHOD: Twenty-four sites from all states participated and provided data on megavoltage simulation, planning and treatment delivery...
December 2016: Journal of Medical Radiation Sciences
Stephen J Tueller, Kiersten L Johnson, Kevin J Grimm, Sarah L Desmarais, Brian G Sellers, Richard A Van Dorn
Factor analytic work on the Positive and Negative Syndrome Scale (PANSS) and Brief Psychiatric Rating Scale (BPRS) has yielded varied and conflicting results. The current study explored potential causes of these discrepancies. Prior research has been limited by small sample sizes and an incorrect assumption that the items are normally distributed when in practice responses are highly skewed ordinal variables. Using simulation methodology, we examined the effects of sample size, (in)correctly specifying item distributions, collapsing rarely endorsed response categories, and four factor analytic models...
December 2, 2016: International Journal of Methods in Psychiatric Research
Xiaomei Zhuang, Chuang Lu
Physiologically based pharmacokinetic (PBPK) modeling and simulation can be used to predict the pharmacokinetic behavior of drugs in humans using preclinical data. It can also explore the effects of various physiologic parameters such as age, ethnicity, or disease status on human pharmacokinetics, as well as guide dose and dose regiment selection and aid drug-drug interaction risk assessment. PBPK modeling has developed rapidly in the last decade within both the field of academia and the pharmaceutical industry, and has become an integral tool in drug discovery and development...
September 2016: Acta Pharmaceutica Sinica. B
Emre Huri, Mehmet Ezer, Eddie Chan
Laparoscopic surgery is routinely used to treat many urological conditions and it is the gold standard treatment option for many surgeries such as radical nephrectomy. Due to the difficulty of learning, laparoscopic training should start outside the operating room. Although it is a very different model of laparoscopic training; the aim of this review is to show the value of human cadaveric model for laparoscopic training and present our experience in this area. Fresh frozen cadaveric model in laparoscopic training, dry lab, cadaveric model, animal models and computer based simulators are the most commonly used models for laparoscopic training...
December 2016: Turkish Journal of Urology
Hans-Sonke Jans
PURPOSE: To present and evaluate an ion chamber-based method for the cross-calibration between sites of activity measurements of unsealed radionuclides. Notably, the method allows direct comparison of short lived (i.e., clinically used) radioisotopes and the cross-calibration of radionuclide activity meters (also known as "dose calibrators"). METHODS: A portable ion chamber has been designed which is easily shipped between sites, e.g., between a standards laboratory and a nuclear medicine department...
December 2016: Medical Physics
José Gardiazabal, Philipp Matthies, Jakob Vogel, Benjamin Frisch, Nassir Navab, Sibylle Ziegler, Tobias Lasser
PURPOSE: Hand- and robot-guided mini gamma cameras have been introduced for the acquisition of single-photon emission computed tomography (SPECT) images. Less cumbersome than whole-body scanners, they allow for a fast acquisition of the radioactivity distribution, for example, to differentiate cancerous from hormonally hyperactive lesions inside the thyroid. This work compares acquisition protocols and reconstruction algorithms in an attempt to identify the most suitable approach for fast acquisition and efficient image reconstruction, suitable for localization of extended sources, such as lesions inside the thyroid...
December 2016: Medical Physics
David Romblom, Catherine Guastavino, Philippe Depalle
The objective of this study is to understand listeners' sensitivity to directional variations in non-ideal diffuse field reverberation. An ABX discrimination test was conducted using a semi-spherical 28-loudspeaker array; perceptual thresholds were estimated by systematically varying the level of a segment of loudspeakers for lateral, height, and frontal conditions. The overall energy was held constant using a gain compensation scheme. When compared to an ideal diffuse field, the perceptual threshold for detection is -2...
November 2016: Journal of the Acoustical Society of America
José M Amigó, Roberto Monetti, Beata Graff, Grzegorz Graff
Most random processes studied in nonlinear time series analysis take values on sets endowed with a group structure, e.g., the real and rational numbers, and the integers. This fact allows to associate with each pair of group elements a third element, called their transcript, which is defined as the product of the second element in the pair times the first one. The transfer entropy of two such processes is called algebraic transfer entropy. It measures the information transferred between two coupled processes whose values belong to a group...
November 2016: Chaos
Jiaheng Wang, Yang Xu, Xintong Ling, Rong Zhang, Zhi Ding, Chunming Zhao
Orthogonal frequency-division multiplexing (OFDM) is a practical technology in visible light communication (VLC) for high-speed transmissions. However, one of its operational limitations is the peak-to-average power ratio (PAPR) of the transmitted signal. In this paper, we analyze the PAPR distributions of four VLC OFDM schemes, namely DC-biased optical OFDM (DCO-OFDM), asymmetrically clipped optical OFDM (ACO-OFDM), pulse amplitude modulated discrete multitone (PAM-DMT), and Flip-OFDM. Both lower and upper clippings are considered...
November 28, 2016: Optics Express
Denis Tihon, Stafford Withington, Christopher N Thomas, Christophe Craeye
In many applications of absorbing structures it is important to understand their spatial response to incident fields, for example in thermal solar panels, bolometric imaging, and controlling radiative heat transfer. In practice, the illuminating field often originates from thermal sources and is only partially spatially coherent when it reaches the absorbing device. In this paper, we present a method to fully characterize the way a structure can absorb such partially coherent fields. The method is presented for any three-dimensional material and accounts for the partial coherence and partial polarization of the incident light...
December 1, 2016: Journal of the Optical Society of America. A, Optics, Image Science, and Vision
Marie Ng, Patrick Liu, Blake Thomson, Christopher J L Murray
BACKGROUND: Understanding trends in the distribution of body mass index (BMI) is a critical aspect of monitoring the global overweight and obesity epidemic. Conventional population health metrics often only focus on estimating and reporting the mean BMI and the prevalence of overweight and obesity, which do not fully characterize the distribution of BMI. In this study, we propose a novel method which allows for the estimation of the entire distribution. METHODS: The proposed method utilizes the optimization algorithm, L-BFGS-B, to derive the distribution of BMI from three commonly available population health statistics: mean BMI, prevalence of overweight, and prevalence of obesity...
March 12, 2016: Population Health Metrics
Jianfang Cao, Lichao Chen, Min Wang, Hao Shi, Yun Tian
Image classification uses computers to simulate human understanding and cognition of images by automatically categorizing images. This study proposes a faster image classification approach that parallelizes the traditional Adaboost-Backpropagation (BP) neural network using the MapReduce parallel programming model. First, we construct a strong classifier by assembling the outputs of 15 BP neural networks (which are individually regarded as weak classifiers) based on the Adaboost algorithm. Second, we design Map and Reduce tasks for both the parallel Adaboost-BP neural network and the feature extraction algorithm...
December 1, 2016: Scientific Reports
Yunxiao Chen, Xiaoou Li, Jingchen Liu, Zhiliang Ying
Diagnostic classification models are confirmatory in the sense that the relationship between the latent attributes and responses to items is specified or parameterized. Such models are readily interpretable with each component of the model usually having a practical meaning. However, parameterized diagnostic classification models are sometimes too simple to capture all the data patterns, resulting in significant model lack of fit. In this paper, we attempt to obtain a compromise between interpretability and goodness of fit by regularizing a latent class model...
November 30, 2016: Psychometrika
Susan Sullivan-Bolyai, Sybil Crawford, Kim Johnson, Neesha Ramchandani, Diane Quinn, Bianca D'Alesandro, Kailyn Stern, Terry Lipman, Gail Melkus, Randi Streisand
There has been a 2% to 3% increase in Type 1 diabetes (T1D) in children below 11 years old. Preteens (9-12 years old) with T1D are often overlooked regarding future diabetes self-management (DSM) expectations because parents are still in the "driver's seat." The study purpose was to explore feasibility/ability to recruit and conduct a two-arm trial on reeducation, collaboration, and social support. One component of DSM was reviewed (hypoglycemia) with preteens (n = 22) and parents (n = 22). The experimental preteens discussed hypoglycemia management with a teen mentor and nurse educator using a human patient simulator for practice, and working collaboratively with parents...
November 2016: Journal of Family Nursing
Xinzhu Wei, Jianzhi Zhang
Gene-environment interaction (G×E) refers to the phenomenon that the same mutation has different phenotypic effects in different environments. Although quantitative trait loci (QTLs) exhibiting G×E have been reported, little is known about the general properties of G×E and those of its underlying QTLs. Here we use the genotypes of 1005 segregants from a cross between two Saccharomyces cerevisiae strains and the growth rates of these segregants in 47 environments to identify growth rate QTLs (gQTLs) in each environment and QTLs that have different growth effects in each pair of environments (g×eQTLs)...
November 30, 2016: Genetics
James R Schmidt
In the Stroop task, participants identify the print color of color words. The congruency effect is the observation that response times and errors are increased when the word and color are incongruent (e.g., the word "red" in green ink) relative to when they are congruent (e.g., "red" in red). The proportion congruent (PC) effect is the finding that congruency effects are reduced when trials are mostly incongruent rather than mostly congruent. This PC effect can be context-specific. For instance, if trials are mostly incongruent when presented in one location and mostly congruent when presented in another location, the congruency effect is smaller for the former location...
2016: Frontiers in Psychology
Diptiman D Bose
Objective. To implement an integrated, comprehensive, and learner-centered elective course focused at exposing learners to the interpretation of electrocardiograms and highlighting the mechanisms underlining the abnormal electrophysiological events. Design. Learners were presented with foundational information on the mechanisms underlying electrophysiological changes associated with the development of arrhythmias. They then discussed the interpretation of electrocardiogram (ECG) recordings and diagnosis of cardiovascular events...
October 25, 2016: American Journal of Pharmaceutical Education
Rebecca D Marjerison, Jeff Melkonian, John L Hutson, Harold M van Es, Shai Sela, Larry D Geohring, Jeffrey Vetsch
Environmental nitrogen (N) losses (e.g., nitrate leaching, denitrification, and ammonia volatilization) frequently occur in maize ( L.) agroecosystems. Decision support systems, designed to optimize the application of N fertilizer in these systems, have been developed using physically based models such as the Precision Nitrogen Management (PNM) model of soil and crop processes, which is an integral component of Adapt-N, a decision support tool providing N fertilizer recommendations for maize production. Such models can also be used to estimate N losses associated with particular management practices and over a range of current climates and future climate projections...
November 2016: Journal of Environmental Quality
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"