19,923 results match your criteria modeling kinetic


Machine learning-based noninvasive quantification of single-imaging session dual-tracer 18F-FDG and 68Ga-DOTATATE dynamic PET-CT in oncology.

IEEE Trans Med Imaging 2021 Sep 14;PP. Epub 2021 Sep 14.

68Ga-DOTATATE PET-CT is routinely used for imaging neuroendocrine tumor (NET) somatostatin receptor subtype 2 (SSTR2) density in patients, and is complementary to FDG PET-CT for improving the accuracy of NET detection, characterization, grading, staging, and predicting/monitoring NET responses to treatment. Performing sequential 18F-FDG and 68Ga-DOTATATE PET scans would require 2 or more days and can delay patient care. To align temporal and spatial measurements of 18F-FDG and 68Ga-DOTATATE PET, and to reduce scan time and CT radiation exposure to patients, we propose a single-imaging session dual-tracer dynamic PET acquisition protocol in the study. Read More

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September 2021

Understanding the Origin of Enhanced Piezoelectric Response in PVDF Matrices with Embedded ZnO Nanoparticles, from Polarizable Molecular Dynamics Simulations.

J Chem Inf Model 2021 Sep 14. Epub 2021 Sep 14.

Omicas Program, Pontificia Universidad Javeriana, Cali 760031, Colombia.

The pervasive use of portable electronic devices, powered from rechargeable batteries, represents a significant portion of the electricity consumption in the world. A sustainable and alternative energy source for these devices would require unconventional power sources, such as harvesting kinetic/potential energy from mechanical vibrations, ultrasound waves, and biomechanical motion, to name a few. Piezoelectric materials transform mechanical deformation into electric fields or, conversely, external electric fields into mechanical motion. Read More

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September 2021

Frustrated peptide chains at the fibril tip control the kinetics of growth of amyloid-β fibrils.

Proc Natl Acad Sci U S A 2021 Sep;118(38)

William A. Brookshire Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204-4004;

Amyloid fibrillization is an exceedingly complex process in which incoming peptide chains bind to the fibril while concertedly folding. The coupling between folding and binding is not fully understood. We explore the molecular pathways of association of Aβ40 monomers to fibril tips by combining time-resolved in situ scanning probe microscopy with molecular modeling. Read More

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September 2021

Spatial spread of COVID-19 outbreak in Italy using multiscale kinetic transport equations with uncertainty.

Math Biosci Eng 2021 08;18(5):7028-7059

Department of Mathematics and Computer Science, University of Ferrara, Via Machiavelli 30, Ferrara 44121, Italy.

In this paper we introduce a space-dependent multiscale model to describe the spatial spread of an infectious disease under uncertain data with particular interest in simulating the onset of the COVID-19 epidemic in Italy. While virus transmission is ruled by a SEIAR type compartmental model, within our approach the population is given by a sum of commuters moving on a extra-urban scale and non commuters interacting only on the smaller urban scale. A transport dynamics of the commuter population at large spatial scales, based on kinetic equations, is coupled with a diffusion model for non commuters at the urban scale. Read More

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Ligand-Driven Grain Engineering of High Mobility Two-Dimensional Perovskite Thin-Film Transistors.

J Am Chem Soc 2021 Sep 13. Epub 2021 Sep 13.

Davidson School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907, United States.

Controlling grain growth is of great importance in maximizing the charge carrier transport for polycrystalline thin-film electronic devices. The thin-film growth of halide perovskite materials has been manipulated via a number of approaches including solvent engineering, composition engineering, and post-treatment processes. However, none of these methods lead to large-scale atomically flat thin films with extremely large grain size and high charge carrier mobility. Read More

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September 2021

and Investigation of S1PR1 Expression in the Central Nervous System Using [H]CS1P1 and [C]CS1P1.

ACS Chem Neurosci 2021 Sep 13. Epub 2021 Sep 13.

Department of Radiology, Washington University School of Medicine, St Louis, Missouri 63110, United States.

Sphingosine-1-phosphate receptor 1 (S1PR1) is ubiquitously expressed among all tissues and plays key roles in many physiological and cellular processes. In the central nervous system (CNS), S1PR1 is expressed in different types of cells including neurons, astrocytes, and oligodendrocyte precursor cells. S1PR1 has been recognized as a novel therapeutic target in multiple sclerosis and other diseases. Read More

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September 2021

Natural Syringyl Mediators Accelerate Laccase-Catalyzed β-O-4 Cleavage and Cα-Oxidation of a Guaiacyl Model Substrate via an Aggregation Mechanism.

ACS Omega 2021 Sep 4;6(35):22578-22588. Epub 2021 Aug 4.

State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, Department of Bioinformatics and Biostatistics, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China.

Laccase-mediator systems (LMSs) have been intensively investigated in lignin degradation. Although only natural metabolites are available for fungal lignin degradation, mediator molecules from metabolites have received substantially less attention than artificial organic-synthetic compounds. It remains unclear which metabolites can accelerate laccase-catalyzed reactions and how those natural mediators influence lignin degradation. Read More

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September 2021

Ab Initio Calculation of Surface Thermochemistry for Popular Solid Transition Metal-Based Species.

ACS Omega 2021 Sep 26;6(35):22525-22536. Epub 2021 Aug 26.

Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190, China.

This work reports the thermochemistry calculations for solid-phase periodic models of ten popular transition metal-based species. These model structures were refined to stable geometry by geometric optimization along with calculating the thermodynamic properties including enthalpy, entropy, heat capacity at constant pressure, and Gibbs free energy by DMol package via first-principles ab initio calculations. The temperature-dependent thermochemistry values were converted to a NASA seven-polynomial format. Read More

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September 2021

Effect of Surface Oxidation on Oxidative Propane Dehydrogenation over Chromia: An Ab Initio Multiscale Kinetic Study.

ACS Catal 2021 Sep 24;11(17):11233-11247. Epub 2021 Aug 24.

Department of Catalysis and Chemical Reaction Engineering, National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana, Slovenia.

An increasingly utilized way for the production of propene is propane dehydrogenation. The reaction presents an alternative to conventional processes based on petroleum resources. In this work, we investigate theoretically how CrO catalyzes this reaction in oxidative and reducing environments. Read More

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September 2021

An kinetic model of 8-oxo-7,8-dihydro-2-deoxyguanosine and 8-oxo-7,8-dihydroguanosine metabolism from intracellular formation to urinary excretion.

Scand J Clin Lab Invest 2021 Sep 11:1-6. Epub 2021 Sep 11.

Institute of Clinical Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark.

Oxidatively generated DNA damage is of paramount importance in a wide range of physiological and pathophysiological processes. Urinary 8-oxo-7,8-dihydro-2-deoxyguanosine (8-oxodG) is often used as an outcome marker in studies on the role of oxidatively generated DNA damage, but its exact relation to intracellular damage levels and variations in DNA repair have been unclear. Using a new approach of quantitative kinetic modeling inspired by pharmacokinetics, we find evidence that in steady state - i. Read More

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September 2021

Center of pressure plausibility for the double-link human stance model under the intermittent control paradigm.

J Biomech 2021 Sep 3;128:110725. Epub 2021 Sep 3.

Department of Information Engineering, Università Politecnica delle Marche, 60131, Ancona, Italy. Electronic address:

Despite human balance maintenance in quiet conditions could seem a trivial motor task, it is not. Recently, the human stance was described through a double link inverted pendulum (DIP) actively controlled at the ankle with an intermittent proportional (P) and derivative (D) control actions based on the sway of a virtual inverted pendulum (VIP) that links the ankle joint with the DIP center of mass. Such description, encompassing both the mechanical model and the intermittent control policy, was referred as the DIP/VIP human stance model, and it showed physiologically plausible kinematic patterns. Read More

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September 2021

Silicate surface coverage controls quinolone transport in saturated porous media.

J Colloid Interface Sci 2021 Aug 24;607(Pt 1):347-356. Epub 2021 Aug 24.

Univ Rennes, Ecole Nationale Supérieure de Chimie de Rennes, UMR CNRS 6226, 11 Allée de Beaulieu, Rennes Cedex 7 F-35708, France; Institut Universitaire de France (IUF), MESRI, 1 rue Descartes, Paris 75231, France. Electronic address:

Although silicates are the most common anions in aquatic systems, little is known on the roles they play on the transport of emerging contaminants, such as antibiotics. Using dynamic column experiments, we revealed the controls of Si loadings on goethite (α-FeOOH) coated sands on the transport of a widely used quinolone antibiotic, here focusing on Nalidixic Acid (NA). We find that dynamic flow-through conditions (Darcy velocities of 2. Read More

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Utilization of layered double hydroxides (LDHs) and their derivatives as photocatalysts for degradation of organic pollutants.

Environ Sci Pollut Res Int 2021 Sep 11. Epub 2021 Sep 11.

Wastewater Technology Division, CSIR-National Environmental Engineering Research Institute, Nagpur, Maharashtra, 440020, India.

Direct or indirect discharge of wastes containing organic pollutants have contributed to the environmental pollution globally. Decontamination of highly polluted natural resources such as water using an effective treatment is a great challenge for public health and environmental protection. Photodegradation of organic pollutants using efficient photocatalyst has attracted extensive interest due to their stability, effectiveness towards degradation efficiency, energy, and cost efficiency. Read More

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September 2021

Numerical model of the spatio-temporal dynamics in a water strider group.

Sci Rep 2021 Sep 10;11(1):18047. Epub 2021 Sep 10.

Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Am Botanischen Garten, 1-9, 24118, Kiel, Germany.

The water strider group demonstrates a very complex dynamics consisting of competition for the food items, territoriality and aggression to the conspecific individuals, escaping from the predators, etc. The situation is even more complex due to the presence of different instars, which in most water strider species live in the same habitat and occupy the same niche. The presented swarm model of water striders demonstrates the realistic population dynamics. Read More

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September 2021

How LEM-based RBE and dose-averaged LET affected clinical outcomes of sacral chordoma patients treated with carbon ion radiotherapy.

Radiother Oncol 2021 Sep 7. Epub 2021 Sep 7.

Fondazione CNAO, Strada Campeggi 53, 27100 Pavia, Italy.

Purpose/objective: To understand the role of relative biological effectiveness (RBE) and dose-averaged linear energy transfer (LET) distributions in the treatment of sacral chordoma (SC) patients with carbon ion radiotherapy (CIRT).

Material/methods: Clinical plans of 50 SC patients consecutively treated before August 2018 with a local effect model-based optimization were recalculated with the modified microdosimetric kinetic RBE model (mMKM). Twenty-six patients were classified as progressive disease and the relapse volume was contoured on the corresponding follow-up diagnostic sequence. Read More

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September 2021

Nucleation limits the lengths of actin filaments assembled by formin.

Biophys J 2021 Sep 7. Epub 2021 Sep 7.

Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455 USA. Electronic address:

Formins stimulate actin polymerization by promoting both filament nucleation and elongation. Because nucleation and elongation draw upon a common pool of actin monomers, the rate at which each reaction proceeds influences the other. This interdependent mechanism determines the number of filaments assembled over the course of a polymerization reaction, as well as their equilibrium lengths. Read More

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September 2021

α-tocopherol, a slow-binding inhibitor of acetylcholinesterase.

Chem Biol Interact 2021 Sep 7:109646. Epub 2021 Sep 7.

Kazan Federal University, Neuropharmacology Laboratory, Kremlevskaya str 18, 480002, Kazan, Russian Federation. Electronic address:

Acetylcholinesterase (AChE) is reversibly inhibited by α-tocopherol (α-T). Steady state kinetic analysis shows that α-T is a mixed slow-binding inhibitor of type A of human enzyme (K = 0.49 μM; K = 1. Read More

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September 2021

Modeling Kinetics and Thermodynamics of Guest Encapsulation into the [ML] Supramolecular Organometallic Cage.

J Chem Inf Model 2021 Sep 10. Epub 2021 Sep 10.

Departament de Química and Centro de Innovación en Química Avanzada (ORFEO-CINQA), Universitat Autònoma de Barcelona, Cerdanyola del Valles, 08193 Cerdanyola del Vallès, Catalonia, Spain.

The encapsulation of molecular guests into supramolecular hosts is a complex molecular recognition process in which the guest displaces the solvent from the host cavity, while the host deforms to let the guest in. An atomistic description of the association would provide valuable insights on the physicochemical properties that guide it. This understanding may be used to design novel host assemblies with improved properties (i. Read More

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September 2021

A Kinetic Response Model for Standardized Regression Analyses of Inflammation-Triggered Hypothermic Body Temperature-Time Courses in Mice.

Front Physiol 2021 24;12:634510. Epub 2021 Aug 24.

Department of Pediatrics, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.

LPS is frequently used to induce experimental endotoxic shock, representing a standard model of acute inflammation in mice. The resulting inflammatory response leads to hypothermia of the experimental animals, which in turn can be used as surrogate for the severity of systemic inflammation. Although increasingly applied as a humane endpoint in murine studies, differences between obtained temperature-time curves are typically evaluated at a single time point with -tests or ANOVA analyses. Read More

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Biomechanical effects of lumbar fusion surgery on adjacent segments using musculoskeletal models of the intact, degenerated and fused spine.

Sci Rep 2021 Sep 9;11(1):17892. Epub 2021 Sep 9.

Division of Applied Mechanics, Department of Mechanical Engineering, Polytechnique, Montréal, QC, Canada.

Adjacent segment disorders are prevalent in patients following a spinal fusion surgery. Postoperative alterations in the adjacent segment biomechanics play a role in the etiology of these conditions. While experimental approaches fail to directly quantify spinal loads, previous modeling studies have numerous shortcomings when simulating the complex structures of the spine and the pre/postoperative mechanobiology of the patient. Read More

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September 2021

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Drug Metab Dispos 2021 Sep 9. Epub 2021 Sep 9.

Pharmaceutical Sciences, Temple University School of Pharmacy, United States

Three CYP3A4 substrates, midazolam, ticlopidine, and diazepam, display non-Michaelis-Menten kinetics, form multiple primary metabolites, and are sequentially metabolized to secondary metabolites. We generated saturation curves for these compounds and analyzed the resulting datasets using a number of single- and multi-substrate binding models. These models were parameterized using rate equations and numerical solutions of the ordinary differential equations. Read More

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September 2021

Complex Cytochrome P450 kinetics due to multisubstrate binding and sequential metabolism. Part 1. Theoretical considerations.

Drug Metab Dispos 2021 Sep 9. Epub 2021 Sep 9.

Pharmaceutical Sciences, Temple University School of Pharmacy, United States

Complexities in CYP mediated metabolism kinetics include multisubstrate binding, multiple product formation and sequential metabolism. Saturation curves and intrinsic clearances were simulated for single substrate and multisubstrate models using derived velocity equations and numerical solutions of ordinary differential equations (ODEs). Multisubstrate models focused on sigmoidal kinetics due to their dramatic impact on clearance predictions. Read More

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September 2021

The Use of Synthetic IMU Signals in the Training of Deep Learning Models Significantly Improves the Accuracy of Joint Kinematic Predictions.

Sensors (Basel) 2021 Aug 31;21(17). Epub 2021 Aug 31.

Center for Orthopedic Biomechanics, University of Denver, Denver, CO 80208, USA.

Gait analysis based on inertial sensors has become an effective method of quantifying movement mechanics, such as joint kinematics and kinetics. Machine learning techniques are used to reliably predict joint mechanics directly from streams of IMU signals for various activities. These data-driven models require comprehensive and representative training datasets to be generalizable across the movement variability seen in the population at large. Read More

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Development and Validation of a Box and Flux Model to Describe Major, Trace and Potentially Toxic Elements (PTEs) in Scottish Soils.

Int J Environ Res Public Health 2021 Aug 25;18(17). Epub 2021 Aug 25.

Scuola di Scienze Agrarie, Forestali, Alimentari ed Ambientali (SAFE), Università della Basilicata, Vialedell'Ateneo Lucano, 10, 85100 Potenza, Italy.

The box and flux model is a mathematical tool used to describe and forecast the major and trace elements perturbations of the Earth biogeochemical cycles. This mathematical tool describes the biogeochemical cycles, using kinetics of first, second and even third order. The theory and history of the box and flux modeling are shortly revised and discussed within the framework of Jim Lovelok's Gaia theory. Read More

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Characterization of Monte Carlo Dynamic/Kinetic Properties of Local Structure in Bond Fluctuation Model of Polymer System.

Materials (Basel) 2021 Aug 31;14(17). Epub 2021 Aug 31.

Department of Theoretical Physics, Wroclaw University of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland.

We report the results of the characterization of local Monte Carlo (MC) dynamics of an equilibrium bond fluctuation model polymer matrix (BFM), in time interval typical for MC simulations of non-linear optical phenomena in host-guest systems. The study contributes to the physical picture of the dynamical aspects of characterized previously in the static regime. The polymer dynamics was studied at three temperatures (below, above and close to the glass transition), using time-dependent generalization of the static parameters which characterize local free volume and local mobility of the matrix. Read More

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Structural requirements of flavonoids for the selective inhibition of α-amylase versus α-glucosidase.

Food Chem 2021 Aug 30;370:130981. Epub 2021 Aug 30.

Whistler Center for Carbohydrate Research and Department of Food Science, Purdue University, West Lafayette, IN 47907, USA. Electronic address:

In the present study, 14 structurally unique flavonoids were screened to systematically investigate structural requirements for selectively inhibiting human α-amylase versus α-glucosidase to obtain a slow but complete starch digestion for health benefit. The selective inhibition property of three flavonoids chosen against the two classes of starch digestive enzymes was confirmed through various analytical techniques - in vitro inhibition assay, fluorescence quenching, kinetic study, and molecular modeling. Considering the chemical structure of flavonoids, the double bond between C2 and C3 and OH groups at A5 and B3 are critical for the inhibition of α-amylase allowing flavonoids to lie parallel on the α-amylase catalytic active site, whereas the OH groups at B3 and C3 are important for α-glucosidase inhibition causing B-ring specific entry into the catalytic active site of α-glucosidase. Read More

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CHIR99021 Promotes hiPSC-Derived Cardiomyocyte Proliferation in Engineered 3D Microtissues.

Adv Healthc Mater 2021 Sep 9:e2100926. Epub 2021 Sep 9.

Experimental Renal and Cardiovascular Research, Department of Nephropathology, Institute of Pathology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Muscle Research Center Erlangen (MURCE), Erlangen, 91054, Germany.

Cardiac tissue engineering is a promising strategy to generate human cardiac tissues for modeling cardiac diseases, screening for therapeutic drugs, and repairing the injured heart. Yet, several issues remain to be resolved including the generation of tissues with high cardiomyocyte density. Here, it is shown that the integration of the glycogen synthase kinase-3β inhibitor CHIR99021 in collagen I hydrogels promotes proliferation of human-induced pluripotent stem cell-derived (hiPSC) cardiomyocytes post-fabrication improving contractility of and calcium flow in engineered 3D cardiac microtissues. Read More

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September 2021

Tuning Cell-Free Composition Controls the Time Delay, Dynamics, and Productivity of TX-TL Expression.

ACS Synth Biol 2021 Sep 9. Epub 2021 Sep 9.

Department of Biological Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, United States.

The composition of cell-free expression systems (TX-TL) is adjusted by adding macromolecular crowding agents and salts. However, the effects of these cosolutes on the dynamics of individual gene expression processes have not been quantified. Here, we carry out kinetic mRNA and protein level measurements on libraries of genetic constructs using the common cosolutes PEG-8000, Ficoll-400, and magnesium glutamate. Read More

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September 2021

Characterization of Compound-Specific, Concentration-Independent Biophysical Properties of Sodium Channel Inhibitor Mechanism of Action Using Automated Patch-Clamp Electrophysiology.

Front Pharmacol 2021 23;12:738460. Epub 2021 Aug 23.

Plant Protection Institute, Centre for Agricultural Research, Martonvásár, Hungary.

We have developed an automated patch-clamp protocol that allows high information content screening of sodium channel inhibitor compounds. We have observed that individual compounds had their specific signature patterns of inhibition, which were manifested irrespective of the concentration. Our aim in this study was to quantify these properties. Read More

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Modeling and Analysis of the Macronutrient Signaling Network in Budding Yeast.

Mol Biol Cell 2021 Sep 8:mbcE20020117. Epub 2021 Sep 8.

Division of Systems Biology, Academy of Integrated Science, Virginia Tech.

Adaptive modulation of the global cellular growth state of unicellular organisms is crucial for their survival in fluctuating nutrient environments. Because these organisms must be able to respond reliably to ever varying and unpredictable nutritional conditions, their nutrient signaling networks must have a certain in-built robustness. In eukaryotes, such as the budding yeast , distinct nutrient signals are relayed by specific plasma membrane receptors to signal transduction pathways that are interconnected in complex information-processing networks, which have been well characterized. Read More

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September 2021