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https://www.readbyqxmd.com/read/28647460/a-prospective-study-evaluating-tobramycin-pharmacokinetics-and-optimal-once-daily-dosing-in-burn-patients
#1
Colin Lee, Sandra A N Walker, Scott E Walker, Winnie Seto, Andrew Simor, Marc Jeschke
BACKGROUND: Once-daily aminoglycoside dosing (ODA) is used in most patient populations to optimize antibacterial activity and reduce toxicity. Unfortunately, burn patients are excluded from ODA due to concerns over altered pharmacokinetics resulting in a shortened half-life and low peak aminoglycoside concentrations. Retrospective studies suggest that ODA may be appropriate if higher milligram/kilogram doses are used. However, no prospective clinical trials in burn patients exist to confirm these findings...
June 21, 2017: Burns: Journal of the International Society for Burn Injuries
https://www.readbyqxmd.com/read/28646868/comprehensive-benchmarking-of-markov-chain-monte-carlo-methods-for-dynamical-systems
#2
Benjamin Ballnus, Sabine Hug, Kathrin Hatz, Linus Görlitz, Jan Hasenauer, Fabian J Theis
BACKGROUND: In quantitative biology, mathematical models are used to describe and analyze biological processes. The parameters of these models are usually unknown and need to be estimated from experimental data using statistical methods. In particular, Markov chain Monte Carlo (MCMC) methods have become increasingly popular as they allow for a rigorous analysis of parameter and prediction uncertainties without the need for assuming parameter identifiability or removing non-identifiable parameters...
June 24, 2017: BMC Systems Biology
https://www.readbyqxmd.com/read/28646012/scatter-correction-with-combined-single-scatter-simulation-and-monte-carlo-simulation-scaling-improved-the-visual-artifacts-and-quantification-in-3d-brain-pet-ct-imaging-with-15-o-gas-inhalation
#3
Keiichi Magota, Tohru Shiga, Yukari Asano, Daiki Shinyama, Jinghan Ye, Amy E Perkins, Piotr J Maniawski, Takuya Toyonaga, Kentaro Kobayashi, Kenji Hirata, Chietsugu Katoh, Naoya Hattori, Nagara Tamaki
In three-dimensional positron emission tomography (PET)/computed tomography (CT) imaging of the brain with (15)O-gas inhalation, high radioactivity in the face mask creates cold artifacts and affects the quantitative accuracy when scatters is corrected by conventional methods (e.g., single-scatter simulation [SSS] with tail-fitting scaling [TFS-SSS]). Here we examined the validity of a newly developed scatter correction method that combines SSS with a scaling factor calculated by Monte Carlo simulation (MCS-SSS)...
June 23, 2017: Journal of Nuclear Medicine: Official Publication, Society of Nuclear Medicine
https://www.readbyqxmd.com/read/28645697/clinical-high-resolution-mapping-of-the-proteoglycan-bound-water-fraction-in-articular-cartilage-of-the-human-knee-joint
#4
Mustapha Bouhrara, David A Reiter, Kyle W Sexton, Christopher M Bergeron, Linda M Zukley, Richard G Spencer
PURPOSE: We applied a recently introduced method to achieve clinically-feasible in-vivo mapping of the proteoglycan water fraction (PgWF) of human knee cartilage with improved spatial resolution and stability as compared to existing methods. MATERIAL AND METHODS: Multicomponent driven equilibrium single-pulse observation of T1 and T2 (mcDESPOT) datasets were acquired from the knees of two healthy young subjects and one older subject with previous knee injury. Each dataset was processed using Bayesian Monte Carlo (BMC) analysis incorporating a two-component tissue model...
June 20, 2017: Magnetic Resonance Imaging
https://www.readbyqxmd.com/read/28645692/clinical-implementation-of-combined-modulated-electron-and-photon-beams-with-conventional-mlc-for-accelerated-partial-breast-irradiation
#5
Carlos Míguez, Elisa Jiménez-Ortega, Bianey A Palma, Hector Miras, Ana Ureba, Rafael Arráns, Francisco Carrasco-Peña, Ana Illescas-Vacas, Antonio Leal
PURPOSE: To report the clinical implementation of a novel external beam radiotherapy technique for accelerated partial breast irradiation treatments based on combined electron and photon modulated beams radiotherapy (MERT+IMRT) with conventional MLC. MATERIALS AND METHODS: A group of patients was selected to test the viability of the technique. The prescribed dose was 38.5Gy, following a hypofractionated schema, and the structures were defined following the NSABP-B39/RTOG-0413 protocol...
June 20, 2017: Radiotherapy and Oncology: Journal of the European Society for Therapeutic Radiology and Oncology
https://www.readbyqxmd.com/read/28645684/detection-and-quantification-of-223-ra-uptake-in-bone-metastases-of-patients-with-castration-resistant-prostate-carcinoma-with-the-aim-of-determining-the-absorbed-dose-in-the-metastases
#6
P Mínguez, A Gómez de Iturriaga, I L Fernández, E Rodeño
PURPOSES: To obtain the necessary acquisition and calibration parameters in order to evaluate the possibility of detecting and quantifying (223)Ra uptake in bone metastases of patients treated for castration resistant prostate carcinoma. Furthermore, in the cases in which the activity can be quantified, to determine the absorbed dose. MATERIAL AND METHODS: Acquisitions from a Petri dish filled with (223)Ra were performed in the gamma camera. Monte Carlo simulations were also performed to study the partial volume effect...
June 20, 2017: Revista Española de Medicina Nuclear e Imagen Molecular
https://www.readbyqxmd.com/read/28644676/is-a-trineutron-resonance-lower-in-energy-than-a-tetraneutron-resonance
#7
S Gandolfi, H-W Hammer, P Klos, J E Lynn, A Schwenk
We present quantum Monte Carlo calculations of few-neutron systems confined in external potentials based on local chiral interactions at next-to-next-to-leading order in chiral effective field theory. The energy and radial densities for these systems are calculated in different external Woods-Saxon potentials. We assume that their extrapolation to zero external-potential depth provides a quantitative estimate of three- and four-neutron resonances. The validity of this assumption is demonstrated by benchmarking with an exact diagonalization in the two-body case...
June 9, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28643833/modelling-critical-casimir-force-induced-self-assembly-experiments-on-patchy-colloidal-dumbbells
#8
Arthur C Newton, T Anh Nguyen, Sandra J Veen, Daniela J Kraft, Peter Schall, Peter G Bolhuis
Colloidal particles suspended in a binary liquid mixture can interact via solvent mediated interactions, known as critical Casimir forces. For anisotropic colloids this interaction becomes directional, which leads to rich phase behavior. While experimental imaging and particle tracking techniques allow determination of isotropic effective potentials via Boltzmann inversion, the modeling of effective interaction in anisotropic systems is non-trivial precisely because of this directionality. Here we extract effective interaction potentials for non-spherical dumbbell particles from observed radial and angular distributions, by employing reference interaction site model (RISM) theory and direct Monte Carlo simulations...
June 23, 2017: Soft Matter
https://www.readbyqxmd.com/read/28643753/dosimetric-characteristic-of-physical-wedge-versus-enhanced-dynamic-wedge-based-on-monte-carlo-simulations
#9
Seied Rabie Mahdavi, Ghazale Geraily, Ahmad Mostaar, Arman Zia, Golbarg Esmaili, Somayeh Farahani
AIM OF STUDY: Physical wedges (PWs) are widely used in radiotherapy to obtain tilted isodose curves, but they alter beam quality. Dynamic wedges (DWs) using moving collimator overcome this problem, but measuring their beam data is not simple. The main aim of this study is to obtain all dosimetric parameters of DWs produced by Varian 2100CD with Monte Carlo simulation and compare them to those from PWs. SUBJECTS AND METHODS: To simulate 6 MV photon beams equipped with PW and DW, BEAMnrc code was used...
April 2017: Journal of Cancer Research and Therapeutics
https://www.readbyqxmd.com/read/28643317/-effect-of-metformin-on-colorectal-carcinoma-in-type-2-diabetes-mellitus-patients-a-markov-model-analysis
#10
Tianhong Su, Bing Liao, Yu Dong, Zhenwei Peng, Qian Zhou, Bin Li, Sui Peng, Ning Zhang
OBJECTIVE: To evaluate the colorectal cancer (CRC) prevention effect of metformin in comparison with that of other T2DM medications from a Markov model perspective. METHODS: Literature concerning CRC morbidity of T2DM patients with metformin or other diabetes medications treatment was reviewed in PubMed and Cochrane Library database from September 2010 to December 2016. INCLUSION CRITERIA: (1)enrolled population was adult patients with T2DM but without CRC; (2) any of the parameters applied in our model was reported; (3) randomized clinical trials (RCTs), quasi-randomized trials, prospective or retrospective cohort studies...
June 25, 2017: Zhonghua Wei Chang Wai Ke za Zhi, Chinese Journal of Gastrointestinal Surgery
https://www.readbyqxmd.com/read/28643157/effect-of-variance-ratio-on-anova-robustness-might-1-5-be-the-limit
#11
María J Blanca, Rafael Alarcón, Jaume Arnau, Roser Bono, Rebecca Bendayan
Inconsistencies in the research findings on F-test robustness to variance heterogeneity could be related to the lack of a standard criterion to assess robustness or to the different measures used to quantify heterogeneity. In the present paper we use Monte Carlo simulation to systematically examine the Type I error rate of F-test under heterogeneity. One-way, balanced, and unbalanced designs with monotonic patterns of variance were considered. Variance ratio (VR) was used as a measure of heterogeneity (1.5, 1...
June 22, 2017: Behavior Research Methods
https://www.readbyqxmd.com/read/28643118/comparison-of-photon-organ-and-effective-dose-coefficients-for-pimal-stylized-phantom-in-bent-positions-in-standard-irradiation-geometries
#12
Shaheen Dewji, K Lisa Reed, Mauritius Hiller
Computational phantoms with articulated arms and legs have been constructed to enable the estimation of radiation dose in different postures. Through a graphical user interface, the Phantom wIth Moving Arms and Legs (PIMAL) version 4.1.0 software can be employed to articulate the posture of a phantom and generate a corresponding input deck for the Monte Carlo N-Particle (MCNP) radiation transport code. In this work, photon fluence-to-dose coefficients were computed using PIMAL to compare organ and effective doses for a stylized phantom in the standard upright position with those for phantoms in realistic work postures...
June 22, 2017: Radiation and Environmental Biophysics
https://www.readbyqxmd.com/read/28642681/%C3%AE-1-containing-gaba-a-receptors-cluster-at-synapses-where-they-mediate-slower-synaptic-currents-than-%C3%AE-2-containing-gaba-a-receptors
#13
Christine L Dixon, Pankaj Sah, Angelo Keramidas, Joseph W Lynch, Nela Durisic
GABA-A receptors (GABAARs) are pentameric ligand-gated ion channels that are assembled mainly from α (α1-6), β (β1-3) and γ (γ1-3) subunits. Although GABAARs containing γ2L subunits mediate most of the inhibitory neurotransmission in the brain, significant expression of γ1 subunits is seen in the amygdala, pallidum and substantia nigra. However, the location and function of γ1-containing GABAARs in these regions remains unclear. In "artificial" synapses, where the subunit composition of postsynaptic receptors is specifically controlled, γ1 incorporation slows the synaptic current decay rate without affecting channel deactivation, suggesting that γ1-containing receptors are not clustered and therefore activated by diffuse neurotransmitter...
2017: Frontiers in Molecular Neuroscience
https://www.readbyqxmd.com/read/28642571/pharmacokinetic-and-pharmacodynamic-modeling-of-cyadox-against-clostridium-perfringens-in-swine
#14
Lei Yan, Shuyu Xie, Dongmei Chen, Yuanhu Pan, Yanfei Tao, Wei Qu, ZhenLi Liu, Zonghui Yuan, Lingli Huang
The purpose of this study was to evaluate the activity of cyadox against Clostridium perfringens in swine and optimize the dosage regimen using ex vivo pharmacokinetic-pharmacodynamic (PK-PD) modeling. After oral administration, the ileum fluid of pigs containing the free cyadox was collected by implanted ultrafiltration probes. The Tmax, AUC24h, and CL/F of free cyadox in the ileum fluid were 1.96 h, 106.40 μg/h/mL, and 0.27 L/kg/h, respectively. Cyadox displayed a concentration-dependent killing action against C...
June 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28642456/predicting-conformational-ensembles-and-genome-wide-transcription-factor-binding-sites-from-dna-sequences
#15
Munazah Andrabi, Andrew Paul Hutchins, Diego Miranda-Saavedra, Hidetoshi Kono, Ruth Nussinov, Kenji Mizuguchi, Shandar Ahmad
DNA shape is emerging as an important determinant of transcription factor binding beyond just the DNA sequence. The only tool for large scale DNA shape estimates, DNAshape was derived from Monte-Carlo simulations and predicts four broad and static DNA shape features, Propeller twist, Helical twist, Minor groove width and Roll. The contributions of other shape features e.g. Shift, Slide and Opening cannot be evaluated using DNAshape. Here, we report a novel method DynaSeq, which predicts molecular dynamics-derived ensembles of a more exhaustive set of DNA shape features...
June 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28641969/determining-3d-kinematics-of-the-hip-using-video-fluoroscopy-guidelines-for-balancing-radiation-dose-and-registration-accuracy
#16
Fabio D'Isidoro, Patrik Eschle, Thomas Zumbrunn, Christian Sommer, Stephan Scheidegger, Stephen J Ferguson
BACKGROUND: Video fluoroscopy is a technique currently used to retrieve the in vivo three-dimensional kinematics of human joints during activities of daily living. Minimization of the radiation dose absorbed by the subject during the measurement is a priority and has not been thoroughly addressed so far. This issue is critical for the motion analysis of the hip joint, because of the proximity of the gonads. The aims of this study were to determine the x-ray voltage and the irradiation angle that minimize the effective dose and to achieve the best compromise between delivered dose and accuracy in motion retrieval...
May 25, 2017: Journal of Arthroplasty
https://www.readbyqxmd.com/read/28641669/effect-of-biological-and-mass-transfer-parameter-uncertainty-on-n%C3%A2-o-emission-estimates-from-wrrfs
#17
Kang Song, Willie F Harper, Yuki Takeuchi, Masaaki Hosomi, Akihiko Terada
  This research used the detailed activated sludge model (ASM) to investigate the effect of parameter uncertainty on nitrous oxide (N2O) emissions from biological wastewater treatment systems. Monte Carlo simulations accounted for uncertainty in the values of the microbial growth parameters and in the volumetric mass transfer coefficient for dissolved oxygen (kLaDO), and the results show that the detailed ASM predicted N2O emission of less than 4% (typically 1%) of the total influent <inline-graphic xmlns:xlink="http://www...
July 1, 2017: Water Environment Research: a Research Publication of the Water Environment Federation
https://www.readbyqxmd.com/read/28641188/risk-assessment-of-triclosan-released-from-sewage-treatment-plants-in-european-rivers-using-a-combination-of-risk-quotient-methodology-and-monte-carlo-simulation
#18
Vasiliki S Thomaidi, Christos Matsoukas, Athanasios S Stasinakis
Ιn this study a probabilistic risk assessment was applied to investigate the environmental risks for the European aquatic environment associated with triclosan (TCS) occurrence in treated wastewater. The concentrations of TCS in effluents of European Sewage Treatment Plants (STPs) were recorded through literature review, while toxicity data was collected for three groups of aquatic organisms (algae, Daphnia magna and fish). The ratio of Measured Environmental Concentration (MEC) and Predicted No Effect Concentration (PNEC), expressed as a Risk Quotient (RQ), was calculated for risk characterization, while Monte Carlo simulation was applied to quantify the associated uncertainty...
June 19, 2017: Science of the Total Environment
https://www.readbyqxmd.com/read/28640950/development-of-a-monte-carlo-multiple-source-model-for-inclusion-in-a-dose-calculation-auditing-tool
#19
Austin M Faught, Scott E Davidson, Jonas Fontenot, Stephen F Kry, Carol Etzel, Geoffrey S Ibbott, David S Followill
PURPOSE: The Imaging and Radiation Oncology Core Houston (IROC-H) (formerly the Radiological Physics Center) has reported varying levels of agreement in their anthropomorphic phantom audits. There is reason to believe one source of error in this observed disagreement is the accuracy of the dose calculation algorithms and heterogeneity corrections used. To audit this component of the radiotherapy treatment process an independent dose calculation tool is needed. METHODS: Monte Carlo multiple source models for Elekta 6MV and 10MV therapeutic x-ray beams were commissioned based on measurement of central axis depth dose data for a 10 x 10 cm(2) field size and dose profiles for a 40 x 40 cm(2) field size...
June 22, 2017: Medical Physics
https://www.readbyqxmd.com/read/28640606/pharmacokinetics-of-mequindox-and-its-marker-residue-1-4-bisdesoxymequindox-in-swine-following-multiple-oral-gavage-and-intramuscular-administration-an-experimental-study-coupled-with-population-physiologically-based-pharmacokinetic-modeling
#20
Dongping Zeng, Zhoumeng Lin, Binghu Fang, Miao Li, Ronette Gehring, Jim E Riviere, ZhenLing Zeng
Mequindox (MEQ) is a quinoxaline-N,N-dioxide antibiotic used in food-producing animals. MEQ residue in animal-derived foods is a food safety concern. The tissue distribution of MEQ and its marker residue 1,4-bisdesoxymequindox (M1) was determined in swine following oral gavage or intramuscular injection twice daily for 3 days. The experimental data were used to construct a flow-limited physiologically based pharmacokinetic (PBPK) model. The model predictions correlated with available data well. Monte Carlo analysis showed that the times needed for M1 concentrations to fall below limit of detection (5 µg/kg) in liver for the 99th percentile of the population were 27 and 34 days after oral gavage and intramuscular administration twice daily for 3 days, respectively...
June 22, 2017: Journal of Agricultural and Food Chemistry
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