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https://www.readbyqxmd.com/read/28240007/delineation-of-margins-for-the-planning-target-volume-ptv-for-image-guided-radiotherapy-igrt-of-gastric-cancer-based-on-intrafraction-motion
#1
Paulina Leszczyńska, Wojciech Leszczyński, Jerzy Wydmański, Dębiec Kinga, Agnieszka Namysł Kaletka, Andrzej Tukiendorf, Leszek Hawrylewicz
Background: Application of the image-guided radiotherapy (IGRT) system for gastric cancer involving daily verification of patient positioning on the treatment machine allows minimisation of geometrical errors as a consequence of intra- and inter-fraction motion. The purpose of this study was to define the intrafraction motion in gastric cancer patients during a treatment session based on the IGRT system and designation of margins around the clinical target volume CTV (internal target volume ITV) necessary to delineate the planning target volume (PTV)...
1, 2017: Asian Pacific Journal of Cancer Prevention: APJCP
https://www.readbyqxmd.com/read/28239929/a-tutorial-on-the-use-of-instrumental-variables-in-pharmacoepidemiology
#2
REVIEW
Ashkan Ertefaie, Dylan S Small, James H Flory, Sean Hennessy
PURPOSE: Instrumental variable (IV) methods are used increasingly in pharmacoepidemiology to address unmeasured confounding. In this tutorial, we review the steps used in IV analyses and the underlying assumptions. We also present methods to assess the validity of those assumptions and describe sensitivity analysis to examine the effects of possible violations of those assumptions. METHODS: Observational studies based on regression or propensity score analyses rely on the untestable assumption that there are no unmeasured confounders...
February 27, 2017: Pharmacoepidemiology and Drug Safety
https://www.readbyqxmd.com/read/28239905/estimators-for-longitudinal-latent-exposure-models-examining-measurement-model-assumptions
#3
Brisa N Sánchez, Sehee Kim, Mary D Sammel
Latent variable (LV) models are increasingly being used in environmental epidemiology as a way to summarize multiple environmental exposures and thus minimize statistical concerns that arise in multiple regression. LV models may be especially useful when multivariate exposures are collected repeatedly over time. LV models can accommodate a variety of assumptions but, at the same time, present the user with many choices for model specification particularly in the case of exposure data collected repeatedly over time...
February 27, 2017: Statistics in Medicine
https://www.readbyqxmd.com/read/28239692/high-throughput-screening-of-microchip-synthesized-genes-in-programmable-double-emulsion-droplets
#4
H F Chan, S Ma, J Tian, K W Leong
The rapid advances in synthetic biology and biotechnology are increasingly demanding high-throughput screening technology, such as screening of the functionalities of synthetic genes for optimization of protein expression. Compartmentalization of single cells in water-in-oil (W/O) emulsion droplets allows screening of a vast number of individualized assays, and recent advances in automated microfluidic devices further help realize the potential of droplet technology for high-throughput screening. However these single-emulsion droplets are incompatible with aqueous phase analysis and the inner droplet environment cannot easily communicate with the external phase...
February 27, 2017: Nanoscale
https://www.readbyqxmd.com/read/28239676/intact-ventral-striatal-prediction-error-signaling-in-medicated-schizophrenia-patients
#5
Adam J Culbreth, Andrew Westbrook, Ziye Xu, Deanna M Barch, James A Waltz
BACKGROUND: Midbrain dopaminergic neurons code a computational quantity, reward prediction error (RPE), which has been causally related to learning. Recently, this insight has been leveraged to link phenomenological and biological levels of understanding in psychiatric disorders, such as schizophrenia. However, results have been mixed, possibly due to small sample sizes. Here we present results from two studies with relatively large Ns to assess VS RPE in schizophrenia. METHODS: In the current study we analyzed data from two independent studies, involving a total of 87 chronic medicated schizophrenia patients and 61 controls...
September 2016: Biological Psychiatry: Cognitive Neuroscience and Neuroimaging
https://www.readbyqxmd.com/read/28239671/development-of-a-model-to-determine-mass-transfer-coefficient-and-oxygen-solubility-in-bioreactors
#6
Johnny Lee
The objective of this paper is to present an experimentally validated mechanistic model to predict the oxygen transfer rate coefficient (Kla) in aeration tanks for different water temperatures. Using experimental data created by Hunter and Vogelaar, the formula precisely reproduces experimental results for the standardized Kla at 20 °C, comparatively better than the current model used by ASCE 2-06 based on the equation Kla20 = Kla. ([Formula: see text])((20-T)) where T is in °C. Currently, reported values for [Formula: see text] range from 1...
February 2017: Heliyon
https://www.readbyqxmd.com/read/28239605/low-dimensional-synergistic-representation-of-bilateral-reaching-movements
#7
Martin K Burns, Vrajeshri Patel, Ionut Florescu, Kishore V Pochiraju, Ramana Vinjamuri
Kinematic and neuromuscular synergies have been found in numerous aspects of human motion. This study aims to determine how effectively kinematic synergies in bilateral upper arm movements can be used to replicate complex activities of daily living (ADL) tasks using a sparse optimization algorithm. Ten right-handed subjects executed 18 rapid and 11 natural-paced ADL tasks requiring bimanual coordination while sitting at a table. A position tracking system was used to track the subjects' arms in space, and angular velocities over time for shoulder abduction, shoulder flexion, shoulder internal rotation, and elbow flexion for each arm were computed...
2017: Frontiers in Bioengineering and Biotechnology
https://www.readbyqxmd.com/read/28239446/mechanism-of-transcription-coupled-dna-modification-recognition
#8
REVIEW
Ji Hyun Shin, Liang Xu, Dong Wang
As a key enzyme for gene expression, RNA polymerase II (pol II) reads along the DNA template and catalyzes accurate mRNA synthesis during transcription. On the other hand, genomic DNA is under constant attack by endogenous and environmental stresses. These attack cause many DNA lesions. Pol II functions as a specific sensor that is able to recognize changes in DNA sequences and structures and induces different outcomes. A critical question in the field is how Pol II recognizes and senses these DNA modifications or lesions...
2017: Cell & Bioscience
https://www.readbyqxmd.com/read/28239345/improvements-in-orientation-and-balancing-abilities-in-response-to-one-month-of-intensive-slackline-training-a-randomized-controlled-feasibility-study
#9
Milos Dordevic, Anita Hökelmann, Patrick Müller, Kathrin Rehfeld, Notger G Müller
Background: Slackline-training has been shown to improve mainly task-specific balancing skills. Non-task specific effects were assessed for tandem stance and preferred one-leg stance on stable and perturbed force platforms with open eyes. It is unclear whether transfer effects exist for other balancing conditions and which component of the balancing ability is affected. Also, it is not known whether slackline-training can improve non-visual-dependent spatial orientation abilities, a function mainly supported by the hippocampus...
2017: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/28239330/a-statistical-method-for-synthesizing-mediation-analyses-using-the-product-of-coefficient-approach-across-multiple-trials
#10
Shi Huang, David P MacKinnon, Tatiana Perrino, Carlos Gallo, Gracelyn Cruden, C Hendricks Brown
Mediation analysis often requires larger sample sizes than main effect analysis to achieve the same statistical power. Combining results across similar trials may be the only practical option for increasing statistical power for mediation analysis in some situations. In this paper, we propose a method to estimate: 1) marginal means for mediation path a, the relation of the independent variable to the mediator; 2) marginal means for path b, the relation of the mediator to the outcome, across multiple trials; and 3) the between-trial level variance-covariance matrix based on a bivariate normal distribution...
November 2016: Statistical Methods & Applications
https://www.readbyqxmd.com/read/28239243/on-modified-dunkl-generalization-of-sz%C3%A3-sz-operators-via-q-calculus
#11
M Mursaleen, Md Nasiruzzaman, Abdullah Alotaibi
The purpose of this paper is to introduce a modification of q-Dunkl generalization of exponential functions. These types of operators enable better error estimation on the interval [Formula: see text] than the classical ones. We obtain some approximation results via a well-known Korovkin-type theorem and a weighted Korovkin-type theorem. Further, we obtain the rate of convergence of the operators for functions belonging to the Lipschitz class.
2017: J Inequal Appl
https://www.readbyqxmd.com/read/28239239/identifying-subgroups-of-enhanced-predictive-accuracy-from-longitudinal-biomarker-data-using-tree-based-approaches-applications-to-fetal-growth
#12
Jared C Foster, Danping Liu, Paul S Albert, Aiyi Liu
Longitudinal monitoring of biomarkers is often helpful for predicting disease or a poor clinical outcome. In this paper, We consider the prediction of both large and small-for-gestational-age births using longitudinal ultrasound measurements, and attempt to identify subgroups of women for whom prediction is more (or less) accurate, should they exist. We propose a tree-based approach to identifying such subgroups, and a pruning algorithm which explicitly incorporates a desired type-I error rate, allowing us to control the risk of false discovery of subgroups...
January 2017: Journal of the Royal Statistical Society. Series A, (Statistics in Society)
https://www.readbyqxmd.com/read/28239236/assessing-composition-and-structure-of-soft-biphasic-media-from-kelvin-voigt-fractional-derivative-model-parameters
#13
Hong Mei Zhang, Yue Wang, Mostafa Fatemi, Michael F Insana
Kelvin-Voigt fractional derivative (KVFD) model parameters have been used to describe viscoelastic properties of soft tissues. However, translating model parameters into a concise set of intrinsic mechanical properties related to tissue composition and structure remains challenging. This paper begins by exploring these relationships using a biphasic emulsion materials with known composition. Mechanical properties are measured by analyzing data from two indentation techniques - ramp-stress relaxation and load-unload hysteresis tests...
March 2017: Measurement Science & Technology
https://www.readbyqxmd.com/read/28239235/quality-control-of-an-hourly-rainfall-dataset-and-climatology-of-extremes-for-the-uk
#14
Stephen Blenkinsop, Elizabeth Lewis, Steven C Chan, Hayley J Fowler
Sub-daily rainfall extremes may be associated with flash flooding, particularly in urban areas but, compared with extremes on daily timescales, have been relatively little studied in many regions. This paper describes a new, hourly rainfall dataset for the UK based on ∼1600 rain gauges from three different data sources. This includes tipping bucket rain gauge data from the UK Environment Agency (EA), which has been collected for operational purposes, principally flood forecasting. Significant problems in the use of such data for the analysis of extreme events include the recording of accumulated totals, high frequency bucket tips, rain gauge recording errors and the non-operation of gauges...
February 2017: International Journal of Climatology: a Journal of the Royal Meteorological Society
https://www.readbyqxmd.com/read/28239230/experimental-analysis-of-steel-beams-subjected-to-fire-enhanced-by-brillouin-scattering-based-fiber-optic-sensor-data
#15
Yi Bao, Yizheng Chen, Matthew S Hoehler, Christopher M Smith, Matthew Bundy, Genda Chen
This paper presents high temperature measurements using a Brillouin scattering-based fiber optic sensor and the application of the measured temperatures and building code recommended material parameters into enhanced thermomechanical analysis of simply supported steel beams subjected to combined thermal and mechanical loading. The distributed temperature sensor captures detailed, nonuniform temperature distributions that are compared locally with thermocouple measurements with less than 4.7% average difference at 95% confidence level...
January 2017: Journal of Structural Engineering (New York, N.Y.)
https://www.readbyqxmd.com/read/28239204/closing-the-sea-level-budget-on-a-regional-scale-trends-and-variability-on-the-northwestern-european-continental-shelf
#16
Thomas Frederikse, Riccardo Riva, Marcel Kleinherenbrink, Yoshihide Wada, Michiel van den Broeke, Ben Marzeion
Long-term trends and decadal variability of sea level in the North Sea and along the Norwegian coast have been studied over the period 1958-2014. We model the spatially nonuniform sea level and solid earth response to large-scale ice melt and terrestrial water storage changes. GPS observations, corrected for the solid earth deformation, are used to estimate vertical land motion. We find a clear correlation between sea level in the North Sea and along the Norwegian coast and open ocean steric variability in the Bay of Biscay and west of Portugal, which is consistent with the presence of wind-driven coastally trapped waves...
October 28, 2016: Geophysical Research Letters
https://www.readbyqxmd.com/read/28239186/a-priori-mesh-grading-for-the-numerical-calculation-of-the-head-related-transfer-functions
#17
Harald Ziegelwanger, Wolfgang Kreuzer, Piotr Majdak
Head-related transfer functions (HRTFs) describe the directional filtering of the incoming sound caused by the morphology of a listener's head and pinnae. When an accurate model of a listener's morphology exists, HRTFs can be calculated numerically with the boundary element method (BEM). However, the general recommendation to model the head and pinnae with at least six elements per wavelength renders the BEM as a time-consuming procedure when calculating HRTFs for the full audible frequency range. In this study, a mesh preprocessing algorithm is proposed, viz...
December 15, 2016: Applied Acoustics. Acoustique Appliqué. Angewandte Akustik
https://www.readbyqxmd.com/read/28238938/estimating-direction-in-brain-behavior-interactions-proactive-and-reactive-brain-states-in-driving
#18
Javier O Garcia, Justin Brooks, Scott Kerick, Tony Johnson, Tim R Mullen, Jean M Vettel
Conventional neuroimaging analyses have ascribed function to particular brain regions, exploiting the power of the subtraction technique in fMRI and event-related potential analyses in EEG. Moving beyond this convention, many researchers have begun exploring network-based neurodynamics and coordination between brain regions as a function of behavioral parameters or environmental statistics; however, most approaches average evoked activity across the experimental session to study task-dependent networks. Here, we examined on-going oscillatory activity as measured with EEG and use a methodology to estimate directionality in brain-behavior interactions...
February 22, 2017: NeuroImage
https://www.readbyqxmd.com/read/28238808/hypophosphatasia-an-overview-for-2017
#19
Michael P Whyte
Hypophosphatasia (HPP) is the inborn-error-of-metabolism that features low serum alkaline phosphatase (ALP) activity (hypophosphatasemia) caused by loss-of-function mutation(s) of the gene that encodes the tissue-nonspecific isoenzyme of ALP (TNSALP). Autosomal recessive or autosomal dominant inheritance from among >300 TNSALP (ALPL) mutations largely explains HPP's remarkably broad-ranging severity. TNSALP is a cell-surface homodimeric phosphohydrolase richly expressed in the skeleton, liver, kidney, and developing teeth...
February 24, 2017: Bone
https://www.readbyqxmd.com/read/28238657/frogs-exploit-statistical-regularities-in-noisy-acoustic-scenes-to-solve-cocktail-party-like-problems
#20
Norman Lee, Jessica L Ward, Alejandro Vélez, Christophe Micheyl, Mark A Bee
Noise is a ubiquitous source of errors in all forms of communication [1]. Noise-induced errors in speech communication, for example, make it difficult for humans to converse in noisy social settings, a challenge aptly named the "cocktail party problem" [2]. Many nonhuman animals also communicate acoustically in noisy social groups and thus face biologically analogous problems [3]. However, we know little about how the perceptual systems of receivers are evolutionarily adapted to avoid the costs of noise-induced errors in communication...
February 17, 2017: Current Biology: CB
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