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Bifurcations

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https://www.readbyqxmd.com/read/28548844/two-dynamical-regimes-of-the-substrate-radical-rearrangement-reaction-in-b12-dependent-ethanolamine-ammonia-lyase-resolve-contributions-of-native-protein-configurations-and-collective-configurational-fluctuations-to-catalysis
#1
Meghan Kohne, Chen Zhu, Kurt Warncke
The kinetics of the substrate radical rearrangement reaction step in B12-dependent ethanolamine ammonia-lyase (EAL) from Salmonella typhimurium are measured over a 92 K temperature range. The observed first-order rate constants display a piecewise-continuous Arrhenius dependence, with linear regions over 295→220 K (monoexponential) and 214→203 K (biexponential) that are delineated by a kinetic bifurcation and kinks at 219 and 217 K, respectively. The results are interpreted by using a free energy landscape model and derived microscopic kinetic mechanism...
May 26, 2017: Biochemistry
https://www.readbyqxmd.com/read/28548524/topologically-enforced-bifurcations-in-superconducting-circuits
#2
G Engelhardt, M Benito, G Platero, T Brandes
The relationship of topological insulators and superconductors and the field of nonlinear dynamics is widely unexplored. To address this subject, we adopt the linear coupling geometry of the Su-Schrieffer-Heeger model, a paradigmatic example for a topological insulator, and render it nonlinearly in the context of superconducting circuits. As a consequence, the system exhibits topologically enforced bifurcations as a function of the topological control parameter, which finally gives rise to chaotic dynamics, separating phases that exhibit clear topological features...
May 12, 2017: Physical Review Letters
https://www.readbyqxmd.com/read/28548461/attending-learning-and-socioeconomic-disadvantage-developmental-cognitive-and-social-neuroscience-of-resilience-and-vulnerability
#3
REVIEW
Kylie Schibli, Kyle Wong, Nina Hedayati, Amedeo D'Angiulli
We review current findings associating socioeconomic status (SES), development of neurocognitive functions, and neurobiological pathways. A sizeable interdisciplinary literature was organized through a bifurcated developmental trajectory (BiDeT) framework, an account of the external and internal variables associated with low SES that may lead to difficulties with attention and learning, along with buffers that may protect against negative outcomes. A consistent neurocognitive finding is that low-SES children attend to information nonselectively, and engage in late filtering out of task-irrelevant information...
May 2017: Annals of the New York Academy of Sciences
https://www.readbyqxmd.com/read/28548171/fluid-shear-stress-combined-with-shear-stress-spatial-gradients-regulates-vascular-endothelial-morphology
#4
Daisuke Yoshino, Naoya Sakamoto, Masaaki Sato
High shear stress (SS) causes local changes around arterial bifurcations, which are common sites for cerebral aneurysms. High SS and SS spatial gradient (SSG) are thought to play important roles in the pathology of cerebral aneurysms. However, whether SS and SSG independently affect the function and morphology of vascular endothelial cells (ECs) exposed to fluid flow remains unclear. This study evaluated the morphology of ECs exposed to various SS and SSG combinations. Confluent ECs were exposed to a SS of 2-60 Pa and a uniform SSG of 0, 5, 10, or 15 Pa mm(-1) for 24 h...
May 26, 2017: Integrative Biology: Quantitative Biosciences From Nano to Macro
https://www.readbyqxmd.com/read/28544680/multiscale-modulation-of-nanocrystalline-cellulose-hydrogel-via-nanocarbon-hybridization-for-3d-neuronal-bilayer-formation
#5
Dongyoon Kim, Subeom Park, Insu Jo, Seong-Min Kim, Dong Hee Kang, Sung-Pyo Cho, Jong Bo Park, Byung Hee Hong, Myung-Han Yoon
Bacterial biopolymers have drawn much attention owing to their unconventional three-dimensional structures and interesting functions, which are closely integrated with bacterial physiology. The nongenetic modulation of bacterial (Acetobacter xylinum) cellulose synthesis via nanocarbon hybridization, and its application to the emulation of layered neuronal tissue, is reported. The controlled dispersion of graphene oxide (GO) nanoflakes into bacterial cellulose (BC) culture media not only induces structural changes within a crystalline cellulose nanofibril, but also modulates their 3D collective association, leading to substantial reduction in Young's modulus (≈50%) and clear definition of water-hydrogel interfaces...
May 22, 2017: Small
https://www.readbyqxmd.com/read/28541601/the-approach-to-coronary-bifurcation-treatment-and-its-outcomes-in-poland-the-single-center-experience
#6
Adam Kern, Robert J Gil, Krystian Bojko, Bartłomiej Rzeszowski, Rakesh Jalali, Jerzy Górny, Jacek Bil
BACKGROUND: Coronary bifurcation lesions pose therapeutic problems during percutaneous coronary interventions. The aim of this study was to analyze the strategy of coronary bifurcation treatment and associated angiographic as well as clinical outcomes in a large hospital in Northern Poland. METHODS: Between January 2012 and January 2014 patients with stable coronary artery disease or non-ST-elevation acute coronary syndrome (NSTE-ACS) were treated with regular drug-eluting stents (rDES) or dedicated bifurcation stents (BiOSS Expert® or BiOSS LIM®)...
May 25, 2017: Cardiology Journal
https://www.readbyqxmd.com/read/28539398/a-balance-of-outward-and-linear-inward-ionic-currents-is-required-for-the-generation-of-slow-wave-oscillations
#7
Jorge Golowasch, Amitabha Bose, Yinzheng Guan, Dalia Salloum, Andrea Roeser, Farzan Nadim
Regenerative inward currents help produce slow oscillations through a negative-slope conductance region of their current-voltage relationship that is well approximated by a linear negative conductance. We used dynamic clamp injections of a linear current with such conductance, INL, to explore why some neurons can generate intrinsic slow oscillations whereas others cannot. We addressed this question, in synaptically isolated neurons of the crab Cancer borealis, after blocking action potentials. The pyloric network consists of a distinct pacemaker and follower neurons, all of which express the same complement of ionic currents...
May 24, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28536994/stability-analysis-of-a-model-of-interaction-between-the-immune-system-and-cancer-cells-in-chronic-myelogenous-leukemia
#8
Apollos Besse, Geoffrey D Clapp, Samuel Bernard, Franck E Nicolini, Doron Levy, Thomas Lepoutre
We describe here a simple model for the interaction between leukemic cells and the autologous immune response in chronic phase chronic myelogenous leukemia (CML). This model is a simplified version of the model we proposed in Clapp et al. (Cancer Res 75:4053-4062, 2015). Our simplification is based on the observation that certain key characteristics of the dynamics of CML can be captured with a three-compartment model: two for the leukemic cells (stem cells and mature cells) and one for the immune response...
May 23, 2017: Bulletin of Mathematical Biology
https://www.readbyqxmd.com/read/28530484/in%C3%A2-vivo-geometry-of-the-kissing-stent-and-covered-endovascular-reconstruction-of-the-aortic-bifurcation-configurations-in-aortoiliac-occlusive-disease
#9
Erik Groot Jebbink, Thijs G Ter Mors, Cornelis H Slump, Robert H Geelkerken, Suzanne Holewijn, Michel Mpj Reijnen
Objectives Various configurations of kissing stent (KS) configurations exist and patency rates vary. In response the covered endovascular reconstruction of the aortic bifurcation configuration was designed to minimize mismatch and improve outcome. The aim of the current study is to compare geometrical mismatch of kissing stent with the covered endovascular reconstruction of the aortic bifurcation configuration in vivo. Methods Post-operative computed tomographic data and patient demographics from 11 covered endovascular reconstruction of the aortic bifurcation and 11 matched kissing stent patients were included...
January 1, 2017: Vascular
https://www.readbyqxmd.com/read/28529795/crystal-structure-of-isopropyl-2-hy-droxy-2-phenyl-acetate-a-pharmacopoeia-reference-standard
#10
Ivan Isaiev, Svitlana Shishkina, Igor Ukrainets, Elena Bevz
The title compound, C11H14O3, is used as a pharmacopoeia reference standard for determining impurities in the drug Pregabalin, used for the treatment of epilepsy and diabetic neuropathic pain. The mol-ecule is far from being planar, with the dihedral angle between the planes of the aromatic ring and the carboxyl fragment (O-C=O) being 76.1 (6)°. The isopropyl substituent is located in a synperiplanar position relative to the C=O bond and is turned so that the C-O-C-H torsion angle is -43.7°. In the crystal, bifurcated O-H⋯(O,O) hydrogen bonds, enclosing R1(2)(5) ring motifs, lead to the formation of chains propagating along the c-axis direction...
May 1, 2017: Acta Crystallographica. Section E, Crystallographic Communications
https://www.readbyqxmd.com/read/28529650/diagnostic-accuracy-of-ga-68-hbed-cc-psma-ligand-pet-ct-before-salvage-lymph-node-dissection-for-recurrent-prostate-cancer
#11
Cordula A Jilg, Vanessa Drendel, H Christian Rischke, Teresa Beck, Werner Vach, Kathrin Schaal, Ulrich Wetterauer, Wolfgang Schultze-Seemann, Philipp T Meyer
Background: By targeting the prostate-specific membrane antigen (PSMA) on prostate cancer (PCa) cells PSMA-PET/CT shows great potential in locating the site of biochemical recurrence even at low PSA (Prostate-specific antigen)-levels. Accurate imaging of PCa recurrent lymph node metastases (LNM) is crucial for metastases directed therapies such as salvage-lymph node dissection (salvage-LND). Objective: To evaluate the diagnostic accuracy of PSMA-PET/CT for detection of affected lymph-node regions at salvage-LND for nodal recurrence of PCa...
2017: Theranostics
https://www.readbyqxmd.com/read/28529143/dynamics-analysis-of-a-delayed-reaction-diffusion-predator-prey-system-with-non-continuous-threshold-harvesting
#12
Xuebing Zhang, Hongyong Zhao
This paper deals with a delayed reaction-diffusion predator-prey model with non-continuous threshold harvesting. Sufficient conditions for the local stability of the regular equilibrium, the existence of Hopf bifurcation and Turing bifurcation are obtained by analyzing the associated characteristic equation. By utilizing upper-lower solution method and Lyapunov functions the globally asymptotically stability of a unique regular equilibrium and asymptotically stability of a unique pseudoequilibrium are studied respectively...
May 19, 2017: Mathematical Biosciences
https://www.readbyqxmd.com/read/28528529/the-influence-of-depolarization-block-on-seizure-like-activity-in-networks-of-excitatory-and-inhibitory-neurons
#13
Christopher M Kim, Duane Q Nykamp
The inhibitory restraint necessary to suppress aberrant activity can fail when inhibitory neurons cease to generate action potentials as they enter depolarization block. We investigate possible bifurcation structures that arise at the onset of seizure-like activity resulting from depolarization block in inhibitory neurons. Networks of conductance-based excitatory and inhibitory neurons are simulated to characterize different types of transitions to the seizure state, and a mean field model is developed to verify the generality of the observed phenomena of excitatory-inhibitory dynamics...
May 20, 2017: Journal of Computational Neuroscience
https://www.readbyqxmd.com/read/28528232/a-mathematical-and-biological-plausible-model-of-decision-execution-regulation-in-go-no-go-tasks-focusing-on-the-fronto-striatal-thalamic-pathway
#14
Golnaz Baghdadi, Farzad Towhidkhah, Reza Rostami
Discovering factors influencing the speed and accuracy of responses in tasks such as "Go/No-Go" is one of issues which have been raised in neurocognitive studies. Mathematical models are considered as tools to identify and to study decision making procedure from different aspects. In this paper, a mathematical model has been presented to show several factors can alter the output of decision making procedure before execution in a "Go/No-Go" task. The dynamic of this model has two stable fixed points, each of them corresponds to the "Press" and "Not-press" responses...
May 13, 2017: Computers in Biology and Medicine
https://www.readbyqxmd.com/read/28526793/genomic-analysis-of-calderihabitans-maritimus-kkc1-a-thermophilic-hydrogenogenic-carboxydotrophic-bacterium-isolated-from-marine-sediment
#15
Kimiho Omae, Yasuko Yoneda, Yuto Fukuyama, Takashi Yoshida, Yoshihiko Sako
Calderihabitans maritimus KKC1 is a thermophilic hydrogenogenic carboxydotroph isolated from a submerged marine caldera. Here, we describe the de novo sequencing and feature analysis of the C. maritimus KKC1 genome. Genome-based phylogenetic analysis confirmed that C. maritimus KKC1 was most closely related to the genus Moorella, which includes well-studied acetogenic members. Comparative genomic analysis revealed that, like Moorella, C. maritimus KKC1 retained both the CO2-reducing Wood-Ljungdahl pathway and energy-converting hydrogenase-based module activated by reduced ferredoxin, but lacked the HydABC and NfnAB electron bifurcating enzymes and pyruvate:ferredoxin oxidoreductase required for ferredoxin reduction during acetogenic growth...
May 19, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28526723/anisotomous-dichotomy-results-from-an-unequal-bifurcation-of-the-original-shoot-apical-meristem-in-diphasiastrum-digitatum-lycopodiaceae
#16
Xiaofeng Yin, Roger D Meicenheimer
PREMISE OF THE STUDY: Two types of dichotomy are recognized in Lycopodiaceae: isotomous (equal) and anisotomous (unequal). Anisotomous dichotomy (anisotomy) has been hypothesized to result from unequal growth of an equal bifurcation of the original shoot apical meristem (SAM). Diphasiastrum digitatum (Lycopodiaceae) exhibits anisotomy at various locations. We thus used D. digitatum to test this classic hypothesis about anisotomy. METHODS: Transverse areas of original and derived SAMs of anisotomy exhibited by the rhizome and the vertical aerial vegetative stem were measured using scanning electron microscopy...
May 19, 2017: American Journal of Botany
https://www.readbyqxmd.com/read/28525557/retinal-vascular-branching-in-healthy-and-diabetic-subjects
#17
Ting Luo, Thomas J Gast, Tyler J Vermeer, Stephen A Burns
Purpose: To measure the effect of nonproliferative diabetic retinopathy (NPDR) on retinal branching. To compare vascular branching in healthy and diabetic subjects with established biophysical models. Methods: Vascular bifurcations in arteries and veins were imaged in 17 NPDR and 26 healthy subjects with the Indiana adaptive optics scanning laser ophthalmoscope (AOSLO). Vessel measurements were grouped according to parent vessel diameters into large (≤50 ∼ <100 μm) and small (≤20 ∼ <50 μm) sizes...
May 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28524127/-an-acute-subdural-hematoma-caused-by-rupture-of-a-middle-cerebral-artery-aneurysm
#18
R S Dzhindzhikhadze, O N Dreval', V A Lazarev, R L Kambiev
Acute subdural hematoma caused by cerebral aneurysm rupture is rare. We describe a clinical case of an acute subdural hematoma developed due to rupture of an aneurysm at the M1 segment bifurcation of the middle cerebral artery (MCA). The acute subdural hematoma associated with intracranial hypertension and transtentorial herniation resulted in a comatose condition. The patient underwent decompressive craniectomy, hematoma removal, and clipping of the aneurysm. A significant improvement was observed in the postoperative period...
2017: Zhurnal Voprosy Neĭrokhirurgii Imeni N. N. Burdenko
https://www.readbyqxmd.com/read/28524121/-the-use-of-high-flow-extracranial-intracranial-artery-bypass-in-pathology-of-the-cerebral-and-brachiocephalic-arteries-technical-features-and-surgical-outcomes
#19
A V Dubovoy, K S Ovsyannikov, V E Guzhin, A V Cherepanov, D M Galaktionov, A M Perfil'ev, A O Sosnov
BACKGROUND: Poor outcomes of surgical treatment for complex cerebral aneurysms due to the development of cerebral ischemia were the cause to use cerebral revascularization surgery for this pathology. OBJECTIVE: the study objective was to master a high-flow extracranial-intracranial (EC-IC) artery bypass technique and evaluate its application in surgical treatment of complex and giant cerebral aneurysms as well as complex lesions of the brachiocephalic arteries. MATERIAL AND METHODS: Fifty two patients underwent high-flow IC-EC bypass surgery; of these, 34 patients had complex cerebral aneurysms, and 18 patients had complex stenotic occlusive lesions of the brachiocephalic arteries...
2017: Zhurnal Voprosy Neĭrokhirurgii Imeni N. N. Burdenko
https://www.readbyqxmd.com/read/28523829/the-prediction-of-viscous-losses-and-pressure-drop-in-models-of-the-human-airways
#20
A K Wells, I P Jones, S Hamill, R Bordas
This paper examines the viscous flow resistance in branching tubes as applied to simplified models of the lungs, and compares the results of Computational Fluid Dynamics (CFD) simulations for a range of conditions with measurement data. The results are in good agreement with the available measurement data for both inspiration and expiration. A detailed sensitivity analysis of the dissipation and viscous resistance in a branch then examines the ratio of the viscous resistance to that for a fully developed Poiseuille flow, Z...
May 18, 2017: International Journal for Numerical Methods in Biomedical Engineering
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