keyword
MENU ▼
Read by QxMD icon Read
search

Bifurcations

keyword
https://www.readbyqxmd.com/read/29352582/a-microfluidic-distributor-combining-minimal-volume-minimal-dispersion-and-minimal-sensitivity-to-clogging
#1
Sander Jespers, Sander Deridder, Gert Desmet
A new type of microfluidic flow distributor (referred to as the mixed mode or MM-distributor) is proposed. Its performance characteristics are determined using computational fluid dynamics (CFD), both in the absence and the presence of clogging, which is an important problem in microfluidic systems. A comparison is made with two existing, well-performing distributor types: the bifurcating (BF) distributor and an optimized diverging distributor, the so-called radially interconnected (RI) distributor. It was found that, in the absence of clogging, the MM-distributor produces only a little more dispersion than the bifurcating (BF) distributor, but much less than the radially interconnected (RI) distributor...
January 12, 2018: Journal of Chromatography. A
https://www.readbyqxmd.com/read/29352464/origin-of-heterogeneous-spiking-patterns-from-continuously-distributed-ion-channel-densities-a-computational-study-in-spinal-dorsal-horn-neurons
#2
Arjun Balachandar, Steven A Prescott
Neurons are often classified by spiking pattern. Yet some neurons exhibit distinct patterns under subtly different test conditions, which suggests that they operate near an abrupt transition, or bifurcation. A set of such neurons may exhibit heterogeneous spiking patterns not because of qualitative differences in which ion channels they express, but rather because quantitative differences in expression levels cause neurons to operate on opposite sides of a bifurcation. Neurons in the spinal dorsal horn, for example, respond to somatic current injection with patterns that include tonic-, single-, gap-, delayed- and reluctant-spiking...
January 20, 2018: Journal of Physiology
https://www.readbyqxmd.com/read/29351689/microvascular-decompression-for-patients-with-hemifacial-spasm-associated-with-common-trunk-anomaly-of-the-cerebellar-arteries-case-study-and-review-of-literature
#3
Ehab El Refaee, Christian Rosenstengel, Joerg Baldauf, Dirk T Pillich, Marc Matthes, Henry W S Schroeder
BACKGROUND: Few previous studies have described the origin of both anterior and posterior inferior cerebellar arteries from one vessel as a common trunk anomaly. No previous studies have clearly described the aforementioned anomaly depending on intraoperative endoscopic visualization. OBJECTIVE: To evaluate the association of a common trunk anomaly with hemifacial spasm, which makes microvascular decompression more challenging. METHODS: All patients with common trunk anomaly associated with hemifacial spasm who received surgical treatment between 2006 and 2015 in our institution were identified in our prospectively collected database...
February 1, 2018: Operative Neurosurgery (Hagerstown, Md.)
https://www.readbyqxmd.com/read/29351598/smooth-muscle-cells-of-intracranial-vessels-from-development-to-disease
#4
Juhana Frösen, Anne Joutel
Cerebrovascular diseases that cause ischemic or hemorrhagic stroke with subsequent loss of life or functional capacity due to damage of the brain tissue are among the leading causes of human suffering and economic burden inflicted by diseases in the developed world. Diseases affecting intracranial vessels are significant contributors to ischemic and hemorrhagic strokes. Brain arteriovenous malformations (bAVM), which are a collection of abnormal blood vessels connecting arteries to veins, are the most common cause of intracranial hemorrhage in children and young adults...
January 16, 2018: Cardiovascular Research
https://www.readbyqxmd.com/read/29351074/two-nematode-species-from-freshwater-and-marine-fishes-in-thailand-including-ascarophis-scatophagi-sp-nov-cystidicolidae-from-scatophagus-argus-scatophagidae
#5
František Moravec, Thanapon Yooyen, Amornrat Sanprick
One new and one known species of parasitic nematodes are reported from Thailand for the first time: Falcaustra kaverii (Karve et Naik,1951) (Kathlaniidae) from the intestine of the freshwater fish Poropuntius deauratus (Valenciennes) (Cyprinidae) (new host record) and Ascarophis scatophagi sp. nov. (Cystidicolidae) from the intestine of the marine fish Scatophagus argus (Linnaeus) (Scatophagidae). The morphology of both these species was studied with the use of light (LM) and scanning electron microscopy (SEM) (the latter method used for F...
March 26, 2018: Acta Parasitologica
https://www.readbyqxmd.com/read/29350685/re-orchestration-of-blood-flow-by-micro-circulations
#6
P A R Meyer
Haemoglobin Video Imaging (HVI) demonstrates conjunctival and episcleral blood flow in man with the resolution of a single erythrocyte. A new method for establishing vessel hierarchy in micro-circulations is described, which recognises either delivery or drainage vessels and references vessel order to the capillary. These tools have been used to characterise blood flow.Anterior ciliary arteries show pulsatile variation in diameter. The episcleral arterial circle that they supply has functional apices with pulsatile flow reversal...
January 19, 2018: Eye
https://www.readbyqxmd.com/read/29350267/modern-work-up-and-extended-resection-in-perihilar-cholangiocarcinoma-the-amc-experience
#7
REVIEW
F Rassam, E Roos, K P van Lienden, J E van Hooft, H J Klümpen, G van Tienhoven, R J Bennink, M R Engelbrecht, A Schoorlemmer, U H W Beuers, J Verheij, M G Besselink, O R Busch, T M van Gulik
AIM: Perihilar cholangiocarcinoma (PHC) is a challenging disease and requires aggressive surgical treatment in order to achieve curation. The assessment and work-up of patients with presumed PHC is multidisciplinary, complex and requires extensive experience. The aim of this paper is to review current aspects of diagnosis, preoperative work-up and extended resection in patients with PHC from the perspective of our own institutional experience with this complex tumor. METHODS: We provided a review of applied modalities in the diagnosis and work-up of PHC according to current literature...
January 19, 2018: Langenbeck's Archives of Surgery
https://www.readbyqxmd.com/read/29349430/surgical-repair-of-a-celiac-artery-aneurysm-using-a-sutureless-proximal-anastomosis-device
#8
Tetsuro Uchida, Azumi Hamasaki, Yoshinori Kuroda, Atsushi Yamashita, Jun Hayashi, Mitsuaki Sadahiro
Some celiac artery aneurysms are not suitable for endovascular therapy. We describe the case of a 63-year-old man with a celiac trunk aneurysm extending to the hepatosplenic bifurcation. The aneurysm was resected and oversewn at the origin from the abdominal aorta. A saphenous vein bypass from the supraceliac aorta to the celiac artery bifurcation was performed using a sutureless anastomotic device (PAS-Port system; Cardica, Redwood City, Calif) to create the proximal anastomosis, eliminating the need for aortic clamping...
December 2017: Journal of Vascular Surgery Cases and Innovative Techniques
https://www.readbyqxmd.com/read/29349412/treatment-of-a-symptomatic-intrathoracic-internal-carotid-artery
#9
Christopher R Brown, Michael R Brown
Intrathoracic common carotid artery bifurcations are an anatomic anomaly with such rarity that only six cases have been reported to date. The true incidence of and preferred treatment options for a diseased intrathoracic common carotid artery bifurcation or internal carotid artery (ICA) have not been clearly described. This case report describes a 72-year-old man who experienced a postoperative right hemispheric stoke after an aortic valve replacement, radiofrequency maze procedure, and left atrial appendage clip...
September 2017: Journal of Vascular Surgery Cases and Innovative Techniques
https://www.readbyqxmd.com/read/29349386/successful-use-of-retrograde-branched-extension-limb-assembling-technique-in-endovascular-repair-of-pararenal-abdominal-aortic-aneurysm
#10
Jiang Xiong, Zhongzhou Hu, Hongpeng Zhang, Huanming Xu, Duanduan Chen, Wei Guo
Surgeon-modified retrograde branched extension limb assembling technique and bridged endografts were successfully used to exclude an asymptomatic pararenal abdominal aortic aneurysm and to reconstruct the superior mesenteric artery and bilateral renal arteries in a case with high-grade celiac artery stenosis, nondilated aorta above the superior mesenteric artery, and large lumen below the renal arteries. In patient-specific models for hemodynamics analysis, enhanced flow diversion to visceral arteries up to 6-month follow-up confirmed treatment feasibility; however, endograft configurations could be improved to avoid sharp corners at bifurcations, thereby ensuring smooth flow transport and possibly reducing risk for endograft narrowing or the development of thrombosis...
June 2017: Journal of Vascular Surgery Cases and Innovative Techniques
https://www.readbyqxmd.com/read/29349371/external-ventricular-drain-as-a-nontraumatic-suction-device-in-carotid-endarterectomy
#11
Alistair Jukes, Rodney Allan
Carotid endarterectomy is a commonly performed operation to remove plaque at the region of the carotid bifurcation. We present our technique to keep the field clear and to minimize potential trauma to the carotid using a neurosurgical external ventricular drain passed behind the common carotid and placed in the dependent position under the arteriotomy.
March 2017: Journal of Vascular Surgery Cases and Innovative Techniques
https://www.readbyqxmd.com/read/29348209/influence-of-water-and-enzyme-spnf-on-the-dynamics-and-energetics-of-the-ambimodal-6-4-4-2-cycloaddition
#12
Zhongyue Yang, Song Yang, Peiyuan Yu, Yanwei Li, Charles Doubleday, Jiyong Park, Ashay Patel, Byung-Sun Jeon, William K Russell, Hung-Wen Liu, David H Russell, Kendall N Houk
SpnF is the first monofunctional Diels-Alder/[6+4]-ase that catalyzes a reaction leading to both Diels-Alder and [6+4] adducts through a single transition state. The environment-perturbed transition-state sampling method has been developed to calculate free energies, kinetic isotope effects, and quasi-classical reaction trajectories of enzyme-catalyzed reactions and the uncatalyzed reaction in water. Energetics calculated in this way reproduce the experiment and show that the normal Diels-Alder transition state is stabilized by H bonds with water molecules, while the ambimodal transition state is favored in the enzyme SpnF by both intramolecular hydrogen bonding and hydrophobic binding...
January 18, 2018: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/29347806/synchrony-induced-modes-of-oscillation-of-a-neural-field-model
#13
Jose M Esnaola-Acebes, Alex Roxin, Daniele Avitabile, Ernest Montbrió
We investigate the modes of oscillation of heterogeneous ring networks of quadratic integrate-and-fire (QIF) neurons with nonlocal, space-dependent coupling. Perturbations of the equilibrium state with a particular wave number produce transient standing waves with a specific temporal frequency, analogously to those in a tense string. In the neuronal network, the equilibrium corresponds to a spatially homogeneous, asynchronous state. Perturbations of this state excite the network's oscillatory modes, which reflect the interplay of episodes of synchronous spiking with the excitatory-inhibitory spatial interactions...
November 2017: Physical Review. E
https://www.readbyqxmd.com/read/29347796/headward-growth-and-branching-in-subterranean-channels
#14
Arshad Kudrolli, Nikolay Ionkin, Andreea Panaitescu
We investigate the erosive growth of channels in a thin subsurface sedimentary layer driven by hydrodynamic drag toward understanding subterranean networks and their relation to river networks charged by ground water. Building on a model based on experimental observations of fluid-driven evolution of bed porosity, we focus on the characteristics of the channel growth and their bifurcations in a horizontal rectangular domain subject to various fluid source and sink distributions. We find that the erosion front between low- and high-porosity regions becomes unstable, giving rise to branched channel networks, depending on the spatial fluctuations of the fluid flow near the front and the degree to which the flow is above the erodibility threshold of the medium...
November 2017: Physical Review. E
https://www.readbyqxmd.com/read/29347775/mode-locking-in-systems-of-globally-coupled-phase-oscillators
#15
Sebastian Eydam, Matthias Wolfrum
We investigate the dynamics of a Kuramoto-type system of globally coupled phase oscillators with equidistant natural frequencies and a coupling strength below the synchronization threshold. It turns out that in such cases one can observe a stable regime of sharp pulses in the mean field amplitude with a pulsation frequency given by spacing of the natural frequencies. This resembles a process known as mode locking in lasers and relies on the emergence of a phase relation induced by the nonlinear coupling. We discuss the role of the first and second harmonics in the phase-interaction function for the stability of the pulsations and present various bifurcating dynamical regimes such as periodically and chaotically modulated mode locking, transitions to phase turbulence, and intermittency...
November 2017: Physical Review. E
https://www.readbyqxmd.com/read/29347743/flat-bands-and-compactons-in-mechanical-lattices
#16
Nathan Perchikov, O V Gendelman
Local configurational symmetry in lattice structures may give rise to stationary, compact solutions, even in the absence of disorder and nonlinearity. These compact solutions are related to the existence of flat dispersion curves (bands). Nonlinearity can destabilize such compactons. One common flat-band-generating system is the one-dimensional cross-stitch model, in which compactons were shown to exist for the photonic lattice with Kerr nonlinearity. The compactons exist there already in the linear regime and are not generally destructed by that nonlinearity...
November 2017: Physical Review. E
https://www.readbyqxmd.com/read/29347715/cusps-enable-line-attractors-for-neural-computation
#17
Zhuocheng Xiao, Jiwei Zhang, Andrew T Sornborger, Louis Tao
Line attractors in neuronal networks have been suggested to be the basis of many brain functions, such as working memory, oculomotor control, head movement, locomotion, and sensory processing. In this paper, we make the connection between line attractors and pulse gating in feed-forward neuronal networks. In this context, because of their neutral stability along a one-dimensional manifold, line attractors are associated with a time-translational invariance that allows graded information to be propagated from one neuronal population to the next...
November 2017: Physical Review. E
https://www.readbyqxmd.com/read/29347700/numerical-design-of-a-t-shaped-microfluidic-device-for-deformability-based-separation-of-elastic-capsules-and-soft-beads
#18
M M Villone, M Trofa, M A Hulsen, P L Maffettone
We propose a square cross-section microfluidic channel with an orthogonal side branch (asymmetric T-shaped bifurcation) for the separation of elastic capsules and soft beads suspended in a Newtonian liquid on the basis of their mechanical properties. The design is performed through three-dimensional direct numerical simulations. When suspended objects start near the inflow channel centerline and the carrier fluid is equally partitioned between the two outflow branches, particle separation can be achieved based on their deformability, with the stiffer ones going "straight" and the softer ones being deviated to the "side" branch...
November 2017: Physical Review. E
https://www.readbyqxmd.com/read/29347648/nonreciprocal-wave-transmission-through-an-extended-discrete-nonlinear-schr%C3%A3-dinger-dimer
#19
Muhammad Abdul Wasay
We analyze a one-dimensional extended discrete nonlinear Schrödinger (DNLS) dimer model for nonreciprocal wave transmission. The extension corresponds to the addition of a nonlocal or intersite nonlinear response in addition to a purely cubic local (on-site) nonlinear response, which refines the purely cubic model and aligns to more realistic situations. We observe that a diodelike action persists in the extended case; however, the inclusion of nonlocal response tends to reduce the diode action. We show that this extension results in achieving the diode effect at lower incoming intensities as compared to the purely cubic case...
November 2017: Physical Review. E
https://www.readbyqxmd.com/read/29347647/fast-and-slow-domino-regimes-in-transient-network-dynamics
#20
Peter Ashwin, Jennifer Creaser, Krasimira Tsaneva-Atanasova
It is well known that the addition of noise to a multistable dynamical system can induce random transitions from one stable state to another. For low noise, the times between transitions have an exponential tail and Kramers' formula gives an expression for the mean escape time in the asymptotic limit. If a number of multistable systems are coupled into a network structure, a transition at one site may change the transition properties at other sites. We study the case of escape from a "quiescent" attractor to an "active" attractor in which transitions back can be ignored...
November 2017: Physical Review. E
keyword
keyword
71557
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"