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https://www.readbyqxmd.com/read/28215045/a-generalized-partially-linear-mean-covariance-regression-model-for-longitudinal-proportional-data-with-applications-to-the-analysis-of-quality-of-life-data-from-cancer-clinical-trials
#1
Xueying Zheng, Guoyou Qin, Dongsheng Tu
Motivated by the analysis of quality of life data from a clinical trial on early breast cancer, we propose in this paper a generalized partially linear mean-covariance regression model for longitudinal proportional data, which are bounded in a closed interval. Cholesky decomposition of the covariance matrix for within-subject responses and generalized estimation equations are used to estimate unknown parameters and the nonlinear function in the model. Simulation studies are performed to evaluate the performance of the proposed estimation procedures...
February 19, 2017: Statistics in Medicine
https://www.readbyqxmd.com/read/28213470/higher-mini-bal-total-protein-concentration-in-early-ards-predicts-faster-resolution-of-lung-injury-measured-by-more-ventilator-free-days
#2
Carolyn M Hendrickson, Jason Abbott, Hanjing Zhuo, Kathleen D Liu, Carolyn S Calfee, Michael A Matthay
The protein concentration of alveolar edema fluid in acute respiratory distress syndrome (ARDS) is dynamic. It reflects alveolar flooding during acute injury as well as fluid and protein clearance over time. We hypothesized that among ARDS patients treated with low tidal volume ventilation, higher concentrations of protein in mini-bronchoalveolar lavage (mBAL) samples would predict slower resolution of lung injury and worse clinical outcomes. Total protein and IgM concentrations in Day 0 mBAL samples from 79 subjects enrolled in the aerosolized albuterol (ALTA) ARDS Network Albuterol trial were measured by colorimetric assay and ELISA respectively...
February 17, 2017: American Journal of Physiology. Lung Cellular and Molecular Physiology
https://www.readbyqxmd.com/read/28213146/linear-ultrasonic-motor-for-absolute-gravimeter
#3
Yue Jian, Zhiyuan Yao, Vadim V Silberschmidt
Thanks to their compactness and suitability for vacuum applications, linear ultrasonic motors are considered as substitutes for classical electromagnetic motors as driving elements in absolute gravimeters. Still, their application is prevented by relatively low power output. To overcome this limitation and provide better stability, a V-type linear ultrasonic motor with a new clamping method is proposed for a gravimeter. In this paper, a mechanical model of stators with flexible clamping components is suggested, according to a design criterion for clamps of linear ultrasonic motors...
February 1, 2017: Ultrasonics
https://www.readbyqxmd.com/read/28212112/cancer-as-robust-intrinsic-state-shaped-by-evolution-a-key-issues-review
#4
Ruoshi Yuan, Xiaomei Zhu, Gaowei Wang, Site Li, Ping Ao
Cancer is a complex disease: its pathology cannot be properly understood in terms of independent players-genes, proteins, molecular pathways, or their simple combinations. This is similar to many-body physics of a condensed phase that many important properties are not determined by a single atom or molecule. The rapidly accumulating large 'omics' data also require a new mechanistic and global underpinning to organize for rationalizing cancer complexity. A unifying and quantitative theory was proposed by some of the present authors that cancer is a robust state formed by the endogenous molecular-cellular network, which is evolutionarily built for the developmental processes and physiological functions...
February 17, 2017: Reports on Progress in Physics
https://www.readbyqxmd.com/read/28211134/effect-of-age-on-the-performance-of-bispectral-and-entropy-indices-during-sevoflurane-pediatric-anesthesia-a-pharmacometric-study
#5
Alberto Sciusco, Joseph F Standing, Yucheng Sheng, Pasquale Raimondo, Gilda Cinnella, Michele Dambrosio
BACKGROUND: Bispectral index (BIS) and entropy monitors have been proposed for use in children, but research has not supported their validity for infants. However, effective monitoring of young children may be even more important than for adults, to aid appropriate anesthetic dosing and reduce the chance of adverse consequences. This prospective study aimed to investigate the relationships between age and the predictive performance of BIS and entropy monitors in measuring the anesthetic drug effects within a pediatric surgery setting...
February 17, 2017: Paediatric Anaesthesia
https://www.readbyqxmd.com/read/28211014/comprehensive-peptide-ion-structure-studies-using-ion-mobility-techniques-part-1-an-advanced-protocol-for-molecular-dynamics-simulations-and-collision-cross-section-calculation
#6
Samaneh Ghassabi Kondalaji, Mahdiar Khakinejad, Amirmahdi Tafreshian, Stephen J Valentine
Collision cross-section (CCS) measurements with a linear drift tube have been utilized to study the gas-phase conformers of a model peptide (acetyl-PAAAAKAAAAKAAAAKAAAAK). Extensive molecular dynamics (MD) simulations have been conducted to derive an advanced protocol for the generation of a comprehensive pool of in-silico structures; both higher energy and more thermodynamically stable structures are included to provide an unbiased sampling of conformational space. MD simulations at 300 K are applied to the in-silico structures to more accurately describe the gas-phase transport properties of the ion conformers including their dynamics...
February 16, 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28209158/gene-regulatory-network-underlying-the-immortalization-of-epithelial-cells
#7
Luis Fernando Méndez-López, Jose Davila-Velderrain, Elisa Domínguez-Hüttinger, Christian Enríquez-Olguín, Juan Carlos Martínez-García, Elena R Alvarez-Buylla
BACKGROUND: Tumorigenic transformation of human epithelial cells in vitro has been described experimentally as the potential result of spontaneous immortalization. This process is characterized by a series of cell-state transitions, in which normal epithelial cells acquire first a senescent state which is later surpassed to attain a mesenchymal stem-like phenotype with a potentially tumorigenic behavior. In this paper we aim to provide a system-level mechanistic explanation to the emergence of these cell types, and to the time-ordered transition patterns that are common to neoplasias of epithelial origin...
February 16, 2017: BMC Systems Biology
https://www.readbyqxmd.com/read/28208697/hybrid-analytical-and-data-driven-modeling-for-feed-forward-robot-control-%C3%A2
#8
René Felix Reinhart, Zeeshan Shareef, Jochen Jakob Steil
Feed-forward model-based control relies on models of the controlled plant, e.g., in robotics on accurate knowledge of manipulator kinematics or dynamics. However, mechanical and analytical models do not capture all aspects of a plant's intrinsic properties and there remain unmodeled dynamics due to varying parameters, unmodeled friction or soft materials. In this context, machine learning is an alternative suitable technique to extract non-linear plant models from data. However, fully data-based models suffer from inaccuracies as well and are inefficient if they include learning of well known analytical models...
February 8, 2017: Sensors
https://www.readbyqxmd.com/read/28208472/non-markovian-linear-response-theory-for-quantum-open-systems-and-its-applications
#9
H Z Shen, D X Li, X X Yi
The Kubo formula is an equation that expresses the linear response of an observable due to a time-dependent perturbation. It has been extended from closed systems to open systems in recent years under the Markovian approximation, but is barely explored for open systems in non-Markovian regimes. In this paper, we derive a formula for the linear response of an open system to a time-independent external field. This response formula is available for both Markovian and non-Markovian dynamics depending on parameters in the spectral density of the environment...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28208471/analysis-of-thermodiffusive-cellular-instabilities-in-continuum-combustion-fronts
#10
Hossein Azizi, Sebastian Gurevich, Nikolas Provatas
We explore numerically the morphological patterns of thermodiffusive instabilities in combustion fronts with a continuum fuel source, within a range of Lewis numbers and ignition temperatures, focusing on the cellular regime. For this purpose, we generalize the recent model of Brailovsky et al. to include distinct process kinetics and reactant heterogeneity. The generalized model is derived analytically and validated with other established models in the limit of infinite Lewis number for zero-order and first-order kinetics...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28208375/stable-parity-time-symmetric-nonlinear-modes-and-excitations-in-a-derivative-nonlinear-schr%C3%A3-dinger-equation
#11
Yong Chen, Zhenya Yan
The effect of derivative nonlinearity and parity-time-symmetric (PT-symmetric) potentials on the wave propagation dynamics is explored in the derivative nonlinear Schrödinger equation, where the physically interesting Scarf-II and harmonic-Hermite-Gaussian potentials are chosen. We study numerically the regions of unbroken and broken linear PT-symmetric phases and find some stable bright solitons of this model in a wide range of potential parameters even though the corresponding linear PT-symmetric phases are broken...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28208373/clustering-determines-the-dynamics-of-complex-contagions-in-multiplex-networks
#12
Yong Zhuang, Alex Arenas, Osman Yağan
We present the mathematical analysis of generalized complex contagions in a class of clustered multiplex networks. The model is intended to understand spread of influence, or any other spreading process implying a threshold dynamics, in setups of interconnected networks with significant clustering. The contagion is assumed to be general enough to account for a content-dependent linear threshold model, where each link type has a different weight (for spreading influence) that may depend on the content (e.g., product, rumor, political view) that is being spread...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28208317/quantum-kramers-model-corrections-to-the-linear-response-theory-for-continuous-bath-spectrum
#13
Ilya Rips
Decay of the metastable state is analyzed within the quantum Kramers model in the weak-to-intermediate dissipation regime. The decay kinetics in this regime is determined by energy exchange between the unstable mode and the stable modes of thermal bath. In our previous paper [Phys. Rev. A 42, 4427 (1990)PLRAAN1050-294710.1103/PhysRevA.42.4427], Grabert's perturbative approach to well dynamics in the case of the discrete bath [Phys. Rev. Lett. 61, 1683 (1988)PRLTAO0031-900710.1103/PhysRevLett.61.1683] has been extended to account for the second order terms in the classical equations of motion (EOM) for the stable modes...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28208315/tracer-counterpermeation-analysis-of-diffusivity-in-finite-length-nanopores-with-and-without-single-file-dynamics
#14
David M Ackerman, James W Evans
We perform a tracer counterpermeation (TCP) analysis for a stochastic model of diffusive transport through a narrow linear pore where passing of species within the pore is inhibited or even excluded (single-file diffusion). TCP involves differently labeled but otherwise identical particles from two decoupled infinite reservoirs adsorbing into opposite ends of the pore, and desorbing from either end. In addition to transient behavior, we assess steady-state concentration profiles, spatial correlations, particle number fluctuations, and diffusion fluxes through the pore...
January 2017: Physical Review. E
https://www.readbyqxmd.com/read/28208232/non-linear-co2-flux-response-to-seven-years-of-experimentally-induced-permafrost-thaw
#15
Marguerite Mauritz, Rosvel Bracho, Gerardo Celis, Jack Hutchings, Susan M Natali, Elaine Pegoraro, Verity G Salmon, Christina Schädel, Elizabeth E Webb, Edward A G Schuur
Rapid Arctic warming is expected to increase global greenhouse gas concentrations as permafrost thaw exposes immense stores of frozen carbon (C) to microbial decomposition. Permafrost thaw also stimulates plant growth, which could offset C loss. Using data from seven years of experimental Air and Soil warming in moist acidic tundra, we show that Soil warming had a much stronger effect on CO2 flux than Air warming. Soil warming caused rapid permafrost thaw and increased ecosystem respiration (Reco), gross primary productivity (GPP), and net summer CO2 storage (NEE)...
February 16, 2017: Global Change Biology
https://www.readbyqxmd.com/read/28207799/modeling-the-leaf-angle-dynamics-in-rice-plant
#16
Yonghui Zhang, Liang Tang, Xiaojun Liu, Leilei Liu, Weixing Cao, Yan Zhu
The leaf angle between stem and sheath (SSA) is an important rice morphological trait. The objective of this study was to develop and validate a dynamic SSA model under different nitrogen (N) rates for selected rice cultivars. The time-course data of SSA were collected in three years, and a dynamic SSA model was developed for different main stem leaf ranks under different N rates for two selected rice cultivars. SSA increased with tiller age. The SSA of the same leaf rank increased with increase in N rate. The maximum SSA increased with leaf rank from the first to the third leaf, then decreased from the third to the final leaf...
2017: PloS One
https://www.readbyqxmd.com/read/28207402/reconstructing-the-temporal-progression-of-biological-data-using-cluster-spanning-trees
#17
Ryan Eshleman, Rahul Singh
Identifying the temporal progression of a set of biological samples is crucial for comprehending the dynamics of the underlying molecular interactions. It is often also a basic step in data denoising and synchronization. Finally, identifying the progression order is crucial for problems like cell lineage identification, disease progression, tumor classification, and epidemiology and thus impacts the spectrum of disciplines spanning basic biology, drug discovery, and public health. Current methods that attempt solving this problem face difficulty when it is necessary to factor-in complex relationships within the data such as grouping, partial ordering or bifurcating or multifurcating progressions...
February 9, 2017: IEEE Transactions on Nanobioscience
https://www.readbyqxmd.com/read/28206835/resilience-in-veterinary-students-and-the-predictive-role-of-mindfulness-and-self-compassion
#18
Michelle McArthur, Caroline Mansfield, Susan Matthew, Sanaa Zaki, Conor Brand, Jena Andrews, Susan Hazel
Resilience is a dynamic and multifaceted process in which individuals draw on personal and contextual resources. In difficult situations, resilient people use specific strategies to learn from the situation without being overcome by it. As stressors are inherent to veterinary work, including long work hours, ethical dilemmas, and challenging interactions with clients, resilience is an important component of professional quality of life. However, while resilience in other health professionals has received attention, it has received little in the veterinary field...
2017: Journal of Veterinary Medical Education
https://www.readbyqxmd.com/read/28201910/mode-specific-excited-state-dynamics-study-of-bis-phenylethynyl-benzene-from-ultrafast-raman-loss-spectroscopy
#19
Khokan Roy, Surajit Kayal, Freek Ariese, Andrew Beeby, Siva Umapathy
Femtosecond transient absorption (fs-TA) and Ultrafast Raman Loss Spectroscopy (URLS) have been applied to reveal the excited state dynamics of bis(phenylethynyl)benzene (BPEB), a model system for one-dimensional molecular wires that have numerous applications in opto-electronics. It is known from the literature that in the ground state BPEB has a low torsional barrier, resulting in a mixed population of rotamers in solution at room temperature. For the excited state this torsional barrier had been calculated to be much higher...
February 14, 2017: Journal of Chemical Physics
https://www.readbyqxmd.com/read/28201898/a-rayleighian-approach-for-modeling-kinetics-of-ionic-transport-in-polymeric-media
#20
Rajeev Kumar, Jyoti P Mahalik, Vera Bocharova, Eric W Stacy, Catalin Gainaru, Tomonori Saito, Mallory P Gobet, Steve Greenbaum, Bobby G Sumpter, Alexei P Sokolov
We report a theoretical approach for analyzing impedance of ionic liquids (ILs) and charged polymers such as polymerized ionic liquids (PolyILs) within linear response. The approach is based on the Rayleigh dissipation function formalism, which provides a computational framework for a systematic study of various factors, including polymer dynamics, in affecting the impedance. We present an analytical expression for the impedance within linear response by constructing a one-dimensional model for ionic transport in ILs/PolyILs...
February 14, 2017: Journal of Chemical Physics
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