Read by QxMD icon Read

Critical velocity

Yun Kyoung Ryu, Reilley P Mathena, Sanghee Lim, Minhye Kwak, Michael Xu, Cyrus D Mintz
BACKGROUND: Early postnatal exposure to general anesthetic agents causes a lasting impairment in learning and memory in animal models. One hypothesis to explain this finding is that exposure to anesthetic agents during critical points in neural development disrupts the formation of brain circuitry. Here, we explore the effects of sevoflurane on the neuronal growth cone, a specialization at the growing end of axons and dendrites that is responsible for the targeted growth that underlies connectivity between neurons...
October 2016: Journal of Neurosurgical Anesthesiology
Ellen L Mintz, Juliana A Passipieri, Daniel Y Lovell, George J Christ
Despite the regenerative capacity of skeletal muscle, permanent functional and/or cosmetic deficits (e.g., volumetric muscle loss (VML) resulting from traumatic injury, disease and various congenital, genetic and acquired conditions are quite common. Tissue engineering and regenerative medicine technologies have enormous potential to provide a therapeutic solution. However, utilization of biologically relevant animal models in combination with longitudinal assessments of pertinent functional measures are critical to the development of improved regenerative therapeutics for treatment of VML-like injuries...
October 7, 2016: Journal of Visualized Experiments: JoVE
Hugo Huisman, Aletta Schutte, Johannes Van Rooyen, Carla Fourie, Ruan Kruger, Wayne Smith, Leandi Lammertyn, Leone Malan, Shani Botha, Carina Mels
OBJECTIVE: Tetrahydrobiopterin (BH4) is a cofactor for nitric oxide synthase (NOS) and may be a critical agent in endothelial function by improving nitric oxide (NO) mediated effects. It is reported that the NO synthesis capacity seems favourable in blacks despite their adverse cardiovascular profile. We therefore compared the concentrations of BH4, as well as blood pressure (BP) and arterial stiffness between black and white teachers. Furthermore, we tested the associations of BH4 with a product and inhibitor of NO synthesis, namely L-citrulline, and symmetric dimethylarginine (SDMA) respectively, in both ethnic groups...
September 2016: Journal of Hypertension
Sang-Chol Lee
Chronic hypertension can result in deleterious effects on various vascular organs including the heart and vessels. Cardiovascular magnetic resonance (CMR) has the unique advantage of the ability to assess ventricular volumes and function, valvular abnormalities, vascular pathology, myocardial perfusion and tissue characterization with high accuracy and reproducibility and also avoid the risk of radiation. As this is the case, CMR seems to be an ideal method for comprehensive assessment of patients with systemic hypertension...
September 2016: Journal of Hypertension
Christine Culpepper, Kendra Hendrickson, Susan Marshall, Jessica Benes, Theresa R Grover
BACKGROUND: Growth and nutrition are critical in neonatal care. Whether feeding guidelines improve growth and nutrition and reduce morbidity is unknown. PURPOSE: Feeding guidelines for very low birth-weight (VLBW) infants were implemented in our neonatal intensive care unit (NICU) to start and achieve full enteral feeds sooner, and increase weight gain over the first month. METHODS: Feeding guidelines for VLBW infants were implemented in January 2014, stratified by birth weight (<750, 750-1000, and 1000-1500 g)...
October 7, 2016: Advances in Neonatal Care: Official Journal of the National Association of Neonatal Nurses
Sadegh Sadeghzadeh
A multi-scale method is employed in this paper to conduct a virtual study of the high-strain behavior of single- and multi-layer graphene sheets and to investigate the design of related graphene-based devices. By bridging the length and time scales by combining the Molecular Dynamics and Finite Element methods together, a comprehensive multiscale model is developed to study the fascinating capabilities of single- and multi-layer graphene sheets in withstanding the impact of ultrafast projectiles. In order to contribute to future developments and innovations in this field, several quantitative and qualitative comparisons are also performed...
October 5, 2016: Journal of Molecular Graphics & Modelling
Laurence Ducharme-Crevier, Michele G Mills, Priya M Mehta, Craig M Smith, Mark S Wainwright
BACKGROUND: The primary objective of this study was to characterize changes in cerebral blood flow measured using transcranial Doppler in children with central nervous system infections. We hypothesized that children with central nervous system infections have abnormal cerebral blood flow, associated with a greater frequency of complications and poor neurological outcome. METHODS: We conducted a single-center, retrospective study of children admitted to the neonatal or pediatric intensive care unit with central nervous system infection and undergoing transcranial Doppler as part of routine care between March 2011 and July 2015...
September 4, 2016: Pediatric Neurology
Elisa Wiedemann, Stefanie Jellinghaus, Georg Ende, Antje Augstein, Ronny Sczech, Ben Wielockx, Sönke Weinert, Ruth H Strasser, David M Poitz
Endothelial migration and proliferation are fundamental processes in angiogenesis and wound healing of injured or inflamed vessels. The present study aimed to investigate the regulation of the Eph/ephrin-system during endothelial proliferation and the impact of the ligand ephrin-A1 on proliferation and migration of human umbilical venous (HUVEC) and arterial endothelial cells (HUAEC). Endothelial cells that underwent contact inhibition showed a massive induction of ephrin-A1. In contrast, an injury to a confluent endothelial layer, associated with induction of migration and proliferation, showed reduced ephrin-A1 levels...
October 11, 2016: Cellular Signalling
Anil Nair, Sameep Chandel, Mithun K Mitra, Sudipto Muhuri, Abhishek Chaudhuri
Recent experiments have demonstrated that dynein motors exhibit catch bonding behavior, in which the unbinding rate of a single dynein decreases with increasing force, for a certain range of force. Motivated by these experiments, we study the effect of catch bonding on unidirectional transport properties of cellular cargo carried by multiple dynein motors. We introduce a threshold force bond deformation (TFBD) model, consistent with the experiments, wherein catch bonding sets in beyond a critical applied load force...
September 2016: Physical Review. E
S K Adhikari
We consider the statics and dynamics of a stable, mobile three-dimensional (3D) spatiotemporal light bullet in a cubic-quintic nonlinear medium with a focusing cubic nonlinearity above a critical value and any defocusing quintic nonlinearity. The 3D light bullet can propagate with a constant velocity in any direction. Stability of the light bullet under a small perturbation is established numerically. We consider frontal collision between two light bullets with different relative velocities. At large velocities the collision is elastic with the bullets emerge after collision with practically no distortion...
September 2016: Physical Review. E
Monica Rodríguez-Bolaños, Nallely Cabrera, Ruy Perez-Montfort
The reactivation of triosephosphate isomerase (TIM) from unfolded monomers induced by guanidine hydrochloride involves different amino acids of its sequence in different stages of protein refolding. We describe a systematic mutagenesis method to find critical residues for certain physico-chemical properties of a protein. The two similar TIMs of Trypanosoma brucei and Trypanosoma cruzi have different reactivation velocities and efficiencies. We used a small number of chimeric enzymes, additive mutants and planned site-directed mutants to produce an enzyme from T...
October 2016: Open Biology
Tom T A Lummen, Raymond J Lamb, Gabriele Berruto, Thomas LaGrange, Luca Dal Negro, F Javier García de Abajo, Damien McGrouther, B Barwick, F Carbone
Capturing and controlling plasmons at buried interfaces with nanometre and femtosecond resolution has yet to be achieved and is critical for next generation plasmonic devices. Here we use light to excite plasmonic interference patterns at a buried metal-dielectric interface in a nanostructured thin film. Plasmons are launched from a photoexcited array of nanocavities and their propagation is followed via photon-induced near-field electron microscopy (PINEM). The resulting movie directly captures the plasmon dynamics, allowing quantification of their group velocity at ∼0...
October 11, 2016: Nature Communications
Shinsuke Mori, Keisuke Hirano, Yoshiaki Ito, Masahiro Yamawaki, Motoharu Araki, Norihiro Kobayashi, Hideyuki Takimura, Yasunari Sakamoto, Masakazu Tsutsumi, Takuro Takama, Yohsuke Honda, Takahiro Tokuda, Kenji Makino, Shigemitsu Shirai
AIM: To investigate the relationship between intravascular ultrasound (IVUS) findings and restenosis after stent implantation for long occlusive femoropopliteal (FP) lesions using the intraluminal approach. METHODS: This was a single-center retrospective study of 45 patients (49 lesions) with de novo long occlusive FP lesions treated with bare metal stents implanted using the intraluminal approach under IVUS guidance from April 2007 to December 2014. All patients were followed up at least 12 months...
October 1, 2016: Journal of Atherosclerosis and Thrombosis
L E May, J D Kieffer
The swimming performance and associated swimming behaviour (i.e. substratum-skimming, station-holding and free swimming) were assessed in shortnose sturgeon Acipenser brevirostrum during critical swimming and endurance swimming tests over a rough and a smooth substratum. It was hypothesized that the addition of a rough substratum in the swimming flume may provide a surface for the A. brevirostrum to grip and offer an energetic advantage. Substratum type did not affect the critical swimming performance, but A...
October 9, 2016: Journal of Fish Biology
Franziska Henrich, Daniela Fell, Dorota Truszkowska, Marcel Weirich, Manos Anyfantakis, Thi-Huong Nguyen, Manfred Wagner, Günter K Auernhammer, Hans-Jürgen Butt
In this work we show that the forced dynamic dewetting of surfactant solutions depends sensitively on the surfactant concentration. To measure this effect, a hydrophobic rotating cylinder was horizontally half immersed in aqueous surfactant solutions. Dynamic contact angles were measured optically by extrapolating the contour of the meniscus to the contact line. Anionic (sodium 1-decanesulfonate, S-1DeS), cationic (cetyl trimethylammonium bromide, CTAB) and nonionic surfactants (C4E1, C8E3 and C12E5) with critical micelle concentrations (CMCs) spanning four orders of magnitude were used...
September 20, 2016: Soft Matter
Marielena Gamboa Castro, Susan E Leggett, Ian Y Wong
Collective behaviors emerge from coordinated cell-cell interactions during the morphogenesis of tissues and tumors. For instance, cells may display density-dependent phase transitions from a fluid-like "unjammed" phase to a solid-like "jammed" phase, while different cell types can "self-sort". Here, we comprehensively track single cell dynamics in mixtures of sheet-forming epithelial cells and dispersed mesenchymal cells. We find that proliferating epithelial cells nucleate multicellular clusters that coarsen at a critical density, arresting migration and strengthening spatial velocity correlations...
October 12, 2016: Soft Matter
Anna Lisa Crowley, Eric Yow, Huiman X Barnhart, Melissa A Daubert, Robert Bigelow, Daniel C Sullivan, Michael Pencina, Pamela S Douglas
BACKGROUND: There is no broadly accepted standard method for assessing the quality of echocardiographic measurements in clinical research reports, despite the recognized importance of this information in assessing the quality of study results. METHODS: Twenty unique clinical studies were identified reporting echocardiographic data quality for determinations of left ventricular (LV) volumes (n = 13), ejection fraction (n = 12), mass (n = 9), outflow tract diameter (n = 3), and mitral Doppler peak early velocity (n = 4)...
October 6, 2016: Journal of the American Society of Echocardiography
Conglin Dong, Chengqing Yuan, Lei Wang, Wei Liu, Xiuqin Bai, Xinping Yan
Frictional vibration and noise caused by water-lubricated rubber stern tube bearings, which are generated under extreme conditions, severely threaten underwater vehicles' survivability and concealment performance. This study investigates the effect of flaky and spherical MoS2 nanoparticles on tribological properties and damping capacity of water-lubricated rubber materials, with the aim of decreasing frictional noise. A CBZ-1 tribo-tester was used to conduct the sliding tests between rubber ring-discs and ZCuSn10Zn2 ring-discs with water lubrication...
October 7, 2016: Scientific Reports
T Inagaki, N L Smith, K M Sherva, S Ramakrishnan
Growing evidence indicates that chronic exposure to Bisphenol A (BPA) may disrupt normal brain function and behavior mediated by gonadotropin-releasing hormone (GnRH) pathways. Previous studies have shown that low dose BPA (200ng/ml) exposure during embryogenesis altered development of extra-hypothalamic GnRH3 systems and non-reproductive locomotor behavior in medaka. Effects of parental low-dose BPA exposure on the development of GnRH3 systems and locomotor behavior of offspring are not well known. This study examines whether the neurophysiological and behavioral effects of BPA in parents (F0 generation) are carried over to their offspring (F1 generation) using stable transgenic medaka embryos/larvae with GnRH3 neurons tagged with green fluorescent protein (GFP)...
October 3, 2016: Neurotoxicology
Kar M Ang, Leslie Y Yeo, Yew M Hung, Ming K Tan
The ability to drive microcentrifugation for efficient micromixing and particle concentration and separation on a microfluidic platform is critical for a wide range of lab-on-a-chip applications. In this work, we investigate the use of amplitude modulation to enhance the efficiency of the microcentrifugal recirculation flows in surface acoustic wave microfluidic systems, thus concomitantly reducing the power consumption in these devices for a given performance requirement-a crucial step in the development of miniaturized, integrated circuits for true portable functionality...
September 2016: Biomicrofluidics
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"