keyword
MENU ▼
Read by QxMD icon Read
search

Systems dynamics model

keyword
https://www.readbyqxmd.com/read/29232711/dependence-of-prevalence-of-contiguous-pathways-in-proteins-on-structural-complexity
#1
Kelly M Thayer, Jesse C Galganov, Avram J Stein
Allostery is a regulatory mechanism in proteins where an effector molecule binds distal from an active site to modulate its activity. Allosteric signaling may occur via a continuous path of residues linking the active and allosteric sites, which has been suggested by large conformational changes evident in crystal structures. An alternate possibility is that the signal occurs in the realm of ensemble dynamics via an energy landscape change. While the latter was first proposed on theoretical grounds, increasing evidence suggests that such a control mechanism is plausible...
2017: PloS One
https://www.readbyqxmd.com/read/29232710/stabilizing-patterns-in-time-neural-network-approach
#2
Nadav Ben-Shushan, Misha Tsodyks
Recurrent and feedback networks are capable of holding dynamic memories. Nonetheless, training a network for that task is challenging. In order to do so, one should face non-linear propagation of errors in the system. Small deviations from the desired dynamics due to error or inherent noise might have a dramatic effect in the future. A method to cope with these difficulties is thus needed. In this work we focus on recurrent networks with linear activation functions and binary output unit. We characterize its ability to reproduce a temporal sequence of actions over its output unit...
December 12, 2017: PLoS Computational Biology
https://www.readbyqxmd.com/read/29232130/atom-transfer-radical-polymerization-of-multi-shelled-cationic-corona-for-the-systemic-delivery-of-sirna
#3
Hyesung Kim, Young Ju Son, Wei Mao, Kam W Leong, Hyuk Sang Yoo
We propose an effective siRNA delivery system by preparing poly(DAMA-HEMA)-multilayered gold nanoparticles using multiple surface-initiated atom transfer radical polymerization (SI-ATRP) processes. The polymeric multilayer structure is characterized by transmission electron microscopy (TEM), matrix-associated laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF), UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS) and ζ-potential. The amount of siRNA electrostatically incorporated into the nanoparticle can be tuned by the number of polymeric shells, which in turn influences the cellular uptake and gene silencing effect...
December 12, 2017: Nano Letters
https://www.readbyqxmd.com/read/29232054/high-speed-microscopy-for-in-vivo-monitoring-of-lymph-dynamics
#4
Mustafa Sarimollaoglu, Amanda J Stolarz, Dmitry A Nedosekin, Brittney R Garner, Terry W Fletcher, Ekaterina I Galanzha, Nancy J Rusch, Vladimir P Zharov
The lymphatic system contributes to body homeostasis by clearing fluid, lipids, plasma proteins, and immune cells from the interstitial space. Many studies have been performed to understand lymphatic function under normal conditions and during disease. Nevertheless, a further improvement in quantification of lymphatic behavior is needed. Here, we present advanced bright-field microscopy for in vivo imaging of lymph vessels and automated quantification of lymphatic function at temporal resolution of 2 ms. Full frame videos were compressed and recorded continuously at up to 540 frames per second...
December 12, 2017: Journal of Biophotonics
https://www.readbyqxmd.com/read/29231868/a-data-driven-response-virtual-sensor-technique-with-partial-vibration-measurements-using-convolutional-neural-network
#5
Shan-Bin Sun, Yuan-Yuan He, Si-Da Zhou, Zhen-Jiang Yue
Measurement of dynamic responses plays an important role in structural health monitoring, damage detection and other fields of research. However, in aerospace engineering, the physical sensors are limited in the operational conditions of spacecraft, due to the severe environment in outer space. This paper proposes a virtual sensor model with partial vibration measurements using a convolutional neural network. The transmissibility function is employed as prior knowledge. A four-layer neural network with two convolutional layers, one fully connected layer, and an output layer is proposed as the predicting model...
December 12, 2017: Sensors
https://www.readbyqxmd.com/read/29231729/simulation-of-calcium-phosphate-species-in-aqueous-solution-force-field-derivation
#6
Raffaella Demichelis, Natalya A Garcia, Paolo Raiteri, Riccardo Innocenti Malini, Colin L Freeman, John H Harding, Julian D Gale
A new force field has been derived for the aqueous calcium phosphate system that aims to reproduce the key thermodynamic properties of the system, including free energies of hydration of the ions and the solubility of the solid mineral phases. Interactions of three phosphate anions (PO 3-, HPO 2- and H PO -) with water were calibrated through comparison with the results 4424 obtained from ab initio molecular dynamics using both GGA and hybrid density functional theory with dispersion corrections. In the solid state, the force field has been evaluated by benchmarking against experiment and other existing models and is shown to reproduce the structural and mechanical properties well, despite the primary focus being on thermodynamics...
December 12, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/29230456/the-role-of-charge-and-proton-transfer-in-fragmentation-of-hydrogen-bonded-nanosystems-the-breakup-of-ammonia-clusters-upon-single-photon-multi-ionization
#7
Bart Oostenrijk, Noelle Walsh, Joakim Laksman, Erik P Månsson, Christian Grunewald, Stacey L Sorensen, Mathieu Gisselbrecht
The charge and proton dynamics in hydrogen-bonded networks are investigated using ammonia as a model system. The fragmentation dynamics of medium-sized clusters (1-2 nm) upon single photon multi-ionization is studied, by analyzing the momenta of small ionic fragments. The observed fragmentation pattern of the doubly- and triply-charged clusters reveals a spatial anisotropy of emission between fragments (back-to-back). Protonated fragments exhibit a distinct kinematic correlation, indicating a delay between ionization and fragmentation (fission)...
December 12, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/29230178/human-cardiac-31p-mr-spectroscopy-at-3-tesla-cannot-detect-failing-myocardial-energy-homeostasis-during-exercise
#8
Adrianus J Bakermans, Jason N Bazil, Aart J Nederveen, Gustav J Strijkers, S Matthijs Boekholdt, Daniel A Beard, Jeroen A L Jeneson
Phosphorus-31 magnetic resonance spectroscopy (31P-MRS) is a unique non-invasive imaging modality for probing in vivo high-energy phosphate metabolism in the human heart. We investigated whether current 31P-MRS methodology would allow for clinical applications to detect exercise-induced changes in (patho-)physiological myocardial energy metabolism. Hereto, measurement variability and repeatability of three commonly used localized 31P-MRS methods [3D image-selected in vivo spectroscopy (ISIS) and 1D ISIS with 1D chemical shift imaging (CSI) oriented either perpendicular or parallel to the surface coil] to quantify the myocardial phosphocreatine (PCr) to adenosine triphosphate (ATP) ratio in healthy humans (n = 8) at rest were determined on a clinical 3 Tesla MR system...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/29230070/assessing-climate-change-impacts-on-the-stability-of-small-tidal-inlets-part-2-data-rich-environments
#9
Trang Minh Duong, Roshanka Ranasinghe, Marcus Thatcher, Sarith Mahanama, Zheng Bing Wang, Pushpa Kumara Dissanayake, Mark Hemer, Arjen Luijendijk, Janaka Bamunawala, Dano Roelvink, Dirkjan Walstra
Climate change (CC) is likely to affect the thousands of bar-built or barrier estuaries (here referred to as Small tidal inlets - STIs) around the world. Any such CC impacts on the stability of STIs, which governs the dynamics of STIs as well as that of the inlet-adjacent coastline, can result in significant socio-economic consequences due to the heavy human utilisation of these systems and their surrounds. This article demonstrates the application of a process based snap-shot modelling approach, using the coastal morphodynamic model Delft3D, to 3 case study sites representing the 3 main STI types; Permanently open, locationally stable inlets (Type 1), Permanently open, alongshore migrating inlets (Type 2) and Seasonally/Intermittently open, locationally stable inlets (Type 3)...
January 1, 2018: Marine Geology
https://www.readbyqxmd.com/read/29229846/understanding-the-mechanisms-of-amorphous-creep-through-molecular-simulation
#10
Penghui Cao, Michael P Short, Sidney Yip
Molecular processes of creep in metallic glass thin films are simulated at experimental timescales using a metadynamics-based atomistic method. Space-time evolutions of the atomic strains and nonaffine atom displacements are analyzed to reveal details of the atomic-level deformation and flow processes of amorphous creep in response to stress and thermal activations. From the simulation results, resolved spatially on the nanoscale and temporally over time increments of fractions of a second, we derive a mechanistic explanation of the well-known variation of creep rate with stress...
December 11, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29229821/critical-dynamics-in-population-vaccinating-behavior
#11
A Demetri Pananos, Thomas M Bury, Clara Wang, Justin Schonfeld, Sharada P Mohanty, Brendan Nyhan, Marcel Salathé, Chris T Bauch
Vaccine refusal can lead to renewed outbreaks of previously eliminated diseases and even delay global eradication. Vaccinating decisions exemplify a complex, coupled system where vaccinating behavior and disease dynamics influence one another. Such systems often exhibit critical phenomena-special dynamics close to a tipping point leading to a new dynamical regime. For instance, critical slowing down (declining rate of recovery from small perturbations) may emerge as a tipping point is approached. Here, we collected and geocoded tweets about measles-mumps-rubella vaccine and classified their sentiment using machine-learning algorithms...
December 11, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29229579/investigation-of-the-pulsatility-of-cerebrospinal-fluid-using-cardiac-gated-intravoxel-incoherent-motion-imaging
#12
Anton S Becker, Andreas Boss, Markus Klarhoefer, Tim Finkenstaedt, Moritz C Wurnig, Cristina Rossi
The quantitative and non-invasive monitoring of cerebrospinal fluid (CSF) dynamics and composition may have high clinical relevance in the management of CSF disorders. In this study, we propose the use of the Intravoxel Incoherent Motion (IVIM) MRI for obtaining simultaneous measurements of CSF self-diffusion and fluid circulation. The rationale for this study was that turbulent fluid and mesoscopic fluid fluctuations can be modeled in a first approximation as a fast diffusion process. In this case, we expect that the fast fluid circulation and slower molecular diffusion dynamics can be quantified, assuming a bi-exponential attenuation pattern of the diffusion-weighted signal in MRI...
December 8, 2017: NeuroImage
https://www.readbyqxmd.com/read/29229425/dynamic-analysis-on-the-calcium-oscillation-model-considering-the-influences-of-mitochondria
#13
Xiang Li, Suxia Zhang, Xijun Liu, Xiaojing Wang, Anqi Zhou, Peng Liu
Based on the model considering the influences of mitochondria, a further theoretical study on the dynamic behaviors of calcium signals is made. First of all, the reason for the generation and disappearance of calcium oscillations is verified in theory. Second, an analysis on the model considering the influences of mitochondria and the model neglecting the influences of mitochondria is carried out. Third, β (representing calcium leak) is introduced and it can be found that with the increase of β, the Hopf bifurcation points of system move towards the decreasing direction of μ (representing stimulus intensity) and calcium oscillations region gradually decreases...
December 8, 2017: Bio Systems
https://www.readbyqxmd.com/read/29229222/two-degree-of-freedom-internal-model-control-pid-design-for-lfc-of-power-systems-via-logarithmic-approximations
#14
Jay Singh, Kalyan Chattterjee, C B Vishwakarma
Load frequency controller has been designed for reduced order model of single area and two-area reheat hydro-thermal power system through internal model control - proportional integral derivative (IMC-PID) control techniques. The controller design method is based on two degree of freedom (2DOF) internal model control which combines with model order reduction technique. Here, in spite of taking full order system model a reduced order model has been considered for 2DOF-IMC-PID design and the designed controller is directly applied to full order system model...
December 8, 2017: ISA Transactions
https://www.readbyqxmd.com/read/29228986/addressing-vulnerability-building-resilience-community-based-adaptation-to-vector-borne-diseases-in-the-context-of-global-change
#15
REVIEW
Kevin Louis Bardosh, Sadie Ryan, Kris Ebi, Susan Welburn, Burton Singer
BACKGROUND: The threat of a rapidly changing planet - of coupled social, environmental and climatic change - pose new conceptual and practical challenges in responding to vector-borne diseases. These include non-linear and uncertain spatial-temporal change dynamics associated with climate, animals, land, water, food, settlement, conflict, ecology and human socio-cultural, economic and political-institutional systems. To date, research efforts have been dominated by disease modeling, which has provided limited practical advice to policymakers and practitioners in developing policies and programmes on the ground...
December 11, 2017: Infectious Diseases of Poverty
https://www.readbyqxmd.com/read/29228949/a-mathematical-model-for-histamine-synthesis-release-and-control-in-varicosities
#16
Janet Best, H F Nijhout, Srimal Samaranayake, Parastoo Hashemi, Michael Reed
BACKGROUND: Histamine (HA), a small molecule that is synthesized from the amino acid histidine, plays an important role in the immune system where it is associated with allergies, inflammation, and T-cell regulation. In the brain, histamine is stored in mast cells and other non-neuronal cells and also acts as a neurotransmitter. The histamine neuron cell bodies are in the tuberomammillary (TM) nucleus of the hypothalamus and these neurons send projections throughout the central nervous system (CNS), in particular to the cerebral cortex, amygdala, basal ganglia, hippocampus, thalamus, retina, and spinal cord...
December 12, 2017: Theoretical Biology & Medical Modelling
https://www.readbyqxmd.com/read/29228877/homogenization-techniques-for-population-dynamics-in-strongly-heterogeneous-landscapes
#17
Brian P Yurk, Christina A Cobbold
An important problem in spatial ecology is to understand how population-scale patterns emerge from individual-level birth, death, and movement processes. These processes, which depend on local landscape characteristics, vary spatially and may exhibit sharp transitions through behavioural responses to habitat edges, leading to discontinuous population densities. Such systems can be modelled using reaction-diffusion equations with interface conditions that capture local behaviour at patch boundaries. In this work we develop a novel homogenization technique to approximate the large-scale dynamics of the system...
December 2018: Journal of Biological Dynamics
https://www.readbyqxmd.com/read/29226571/mouse-models-of-psoriasis-and-their-relevance
#18
REVIEW
Kimiko Nakajima, Shigetoshi Sano
Psoriasis is an inflammatory skin disorder that includes dynamic interactions between the immune system and skin and is clinically characterized by keratinocyte proliferation and distinct inflammatory cell infiltrates. Cross-talk between keratinocytes and immunocytes is essential for the development of psoriasis given that it mediates the production of cytokines, chemokines and growth factors. To resolve the pathogenesis of psoriasis, numerous experimental animal models have been generated. In this review, we discuss recent findings from mouse models, their relevancy to psoriasis and use, including the discovery of new therapies...
December 10, 2017: Journal of Dermatology
https://www.readbyqxmd.com/read/29225502/on-the-analysis-of-the-double-hopf-bifurcation-in-machining-processes-via-centre-manifold-reduction
#19
T G Molnar, Z Dombovari, T Insperger, G Stepan
The single-degree-of-freedom model of orthogonal cutting is investigated to study machine tool vibrations in the vicinity of a double Hopf bifurcation point. Centre manifold reduction and normal form calculations are performed to investigate the long-term dynamics of the cutting process. The normal form of the four-dimensional centre subsystem is derived analytically, and the possible topologies in the infinite-dimensional phase space of the system are revealed. It is shown that bistable parameter regions exist where unstable periodic and, in certain cases, unstable quasi-periodic motions coexist with the equilibrium...
November 2017: Proceedings. Mathematical, Physical, and Engineering Sciences
https://www.readbyqxmd.com/read/29224971/biomechanical-effects-of-a-mandibular-advancement-device-on-the-temporomandibular-joint
#20
David S P Heidsieck, Jan Harm Koolstra, Maurits H T de Ruiter, Aarnoud Hoekema, Jan de Lange
PURPOSE: Mandibular advancement devices are commonly used in the treatment of patients with mild to moderate obstructive sleep apnea (OSA). Designed to maintain the mandible in forced protrusion while being worn, mandibular advancement devices (MADs) are intended to increase the upper airway during sleep, thereby reducing OSA symptoms. Depending on the extent of mandibular protrusion, side effects including temporomandibular joint dysfunction are frequently reported. These are likely to reduce overall treatment success by affecting therapeutic adherence...
November 22, 2017: Journal of Cranio-maxillo-facial Surgery
keyword
keyword
54333
1
2
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"