WorldWideScience

Sample records for physiologically relevant flow

  1. Setup of a Biomedical Facility to Study Physiologically Relevant Flow-Structure Interactions

    Science.gov (United States)

    Mehdi, Faraz; Sheng, Jian

    2013-11-01

    The design and implementation of a closed loop biomedical facility to study arterial flows is presented. The facility has a test section of 25 inches, and is capable of generating both steady and pulsatile flows via a centrifugal and a dual piston pump respectively. The Reynolds and Womersley numbers occurring in major blood vessels can be matched. The working fluid is a solution of NaI that allows refractive index matching with both rigid glass and compliant polymer models to facilitate tomographic PIV and holographic PIV. The combination of these two techniques allows us to study both large scale flow features as well as flows very close to the wall. The polymer models can be made with different modulus of elasticity and can be pre-stressed using a 5-axis stage. Radially asymmetric patches can also be pre-fabricated and incorporated in the tube during the manufacturing process to simulate plaque formation in arteries. These tubes are doped with tracer particles allowing for the measurement of wall deformation. Preliminary flow data over rigid and compliant walls is presented. One of the aims of this study is to characterize the changes in flow as the compliancy of blood vessels change due to age or disease, and explore the fluid interactions with an evolving surface boundary.

  2. Flow pumping system for physiological waveforms.

    Science.gov (United States)

    Tsai, William; Savaş, Omer

    2010-02-01

    A pulsatile flow pumping system is developed to replicate flow waveforms with reasonable accuracy for experiments simulating physiological blood flows at numerous points in the body. The system divides the task of flow waveform generation between two pumps: a gear pump generates the mean component and a piston pump generates the oscillatory component. The system is driven by two programmable servo controllers. The frequency response of the system is used to characterize its operation. The system has been successfully tested in vascular flow experiments where sinusoidal, carotid, and coronary flow waveforms are replicated.

  3. Bioprinting towards Physiologically Relevant Tissue Models for Pharmaceutics.

    Science.gov (United States)

    Peng, Weijie; Unutmaz, Derya; Ozbolat, Ibrahim T

    2016-09-01

    Improving the ability to predict the efficacy and toxicity of drug candidates earlier in the drug discovery process will speed up the introduction of new drugs into clinics. 3D in vitro systems have significantly advanced the drug screening process as 3D tissue models can closely mimic native tissues and, in some cases, the physiological response to drugs. Among various in vitro systems, bioprinting is a highly promising technology possessing several advantages such as tailored microarchitecture, high-throughput capability, coculture ability, and low risk of cross-contamination. In this opinion article, we discuss the currently available tissue models in pharmaceutics along with their limitations and highlight the possibilities of bioprinting physiologically relevant tissue models, which hold great potential in drug testing, high-throughput screening, and disease modeling. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. A Review Relevant to Turbomachinery Flows

    Directory of Open Access Journals (Sweden)

    James P. Johnston

    1998-01-01

    “buoyancy” currents in cases where density gradients occur. Turbulence modification involves reduction (stabilization or increase (destabilization of turbulent Reynolds stresses by Coriolis forces; effects which areof special importance for the understanding and prediction of flows in radial and mixed flow pump and compressor rotors. Stabilization/destabilization effects are discussed by a selective review of the basic research literature on flows in straight, radial, rotating channels and diffusers.

  5. Waveform shape analysis: extraction of physiologically relevant information from Doppler recordings.

    Science.gov (United States)

    Ramsay, M M; Broughton Pipkin, F; Rubin, P C; Skidmore, R

    1994-05-01

    1. Doppler recordings were made from the brachial artery of healthy female subjects during a series of manoeuvres which altered the pressure-flow characteristics of the vessel. 2. Changes were induced in the peripheral circulation of the forearm by the application of heat or ice-packs. A sphygmomanometer cuff was used to create graded occlusion of the vessel above and below the point of measurement. Recordings were also made whilst the subjects performed a standardized Valsalva manoeuvre. 3. The Doppler recordings were analysed both with the standard waveform indices (systolic/diastolic ratio, pulsatility index and resistance index) and by the method of Laplace transform analysis. 4. The waveform parameters obtained by Laplace transform analysis distinguished the different changes in flow conditions; they thus had direct physiological relevance, unlike the standard waveform indices.

  6. Comparison of PIV with 4D-Flow in a physiological accurate flow phantom

    Science.gov (United States)

    Sansom, Kurt; Balu, Niranjan; Liu, Haining; Aliseda, Alberto; Yuan, Chun; Canton, Maria De Gador

    2016-11-01

    Validation of 4D MRI flow sequences with planar particle image velocimetry (PIV) is performed in a physiologically-accurate flow phantom. A patient-specific phantom of a carotid artery is connected to a pulsatile flow loop to simulate the 3D unsteady flow in the cardiovascular anatomy. Cardiac-cycle synchronized MRI provides time-resolved 3D blood velocity measurements in clinical tool that is promising but lacks a robust validation framework. PIV at three different Reynolds numbers (540, 680, and 815, chosen based on +/- 20 % of the average velocity from the patient-specific CCA waveform) and four different Womersley numbers (3.30, 3.68, 4.03, and 4.35, chosen to reflect a physiological range of heart rates) are compared to 4D-MRI measurements. An accuracy assessment of raw velocity measurements and a comparison of estimated and measureable flow parameters such as wall shear stress, fluctuating velocity rms, and Lagrangian particle residence time, will be presented, with justification for their biomechanics relevance to the pathophysiology of arterial disease: atherosclerosis and intimal hyperplasia. Lastly, the framework is applied to a new 4D-Flow MRI sequence and post processing techniques to provide a quantitative assessment with the benchmarked data. Department of Education GAANN Fellowship.

  7. Lab-on-a-brane: A novel physiologically relevant planar arterial model to study transendothelial transport

    Science.gov (United States)

    Budhwani, Karim Ismail

    The tremendous quality of life impact notwithstanding, cardiovascular diseases and Cancer add up to over US$ 700bn each year in financial costs alone. Aging and population growth are expected to further expand the problem space while drug research and development remain expensive. However, preclinical costs can be substantially mitigated by substituting animal models with in vitro devices that accurately model human cardiovascular transport. Here we present a novel physiologically relevant lab-on-a-brane that simulates in vivo pressure, flow, strain, and shear waveforms associated with normal and pathological conditions in large and small blood vessels for studying molecular transport across the endothelial monolayer. The device builds upon previously demonstrated integrated microfluidic loop design by: (a) introducing nanoscale pores in the substrate membrane to enable transmembrane molecular transport, (b) transforming the substrate membrane into a nanofibrous matrix for 3D smooth muscle cell (SMC) tissue culture, (c) integrating electrospinning fabrication methods, (d) engineering an invertible sandwich cell culture device architecture, and (e) devising a healthy co-culture mechanism for human arterial endothelial cell (HAEC) monolayer and multiple layers of human smooth muscle cells (HSMC) to accurately mimic arterial anatomy. Structural and mechanical characterization was conducted using confocal microscopy, SEM, stress/strain analysis, and infrared spectroscopy. Transport was characterized using FITC-Dextran hydraulic permeability protocol. Structure and transport characterization successfully demonstrate device viability as a physiologically relevant arterial mimic for testing transendothelial transport. Thus, our lab-on-a-brane provides a highly effective and efficient, yet considerably inexpensive, physiologically relevant alternative for pharmacokinetic evaluation; possibly reducing animals used in pre-clinical testing, clinical trials cost from false

  8. Cerebral blood flow: Physiologic and clinical aspects

    International Nuclear Information System (INIS)

    Wood, J.H.

    1987-01-01

    This book contains 46 chapters divided among nine sections. The section titles are: Historical Perspectives; Cerebrovascular Anatomy; Cerebrovascular Physiology; Methods of Clinical Measurement; Experimental Methods; Imaging of Cerebral Circulation; Cerebrovascular Pathophysiology; Cerebrovascular Pharmacology; and Surgical and Interventional Augmentation

  9. [Anatomy, physiology and clinical relevance of the connecting tubule].

    Science.gov (United States)

    Miranda, N; Simeoni, M A; Ciriana, E; Panico, C; Cappello, E; Capasso, G B

    2009-01-01

    The cortical distal nephron is the site of fine regulation of salt and water excretion by peptide and mineralocorticoid hormones and the site for specific actions of diuretics. Some data suggest that sodium reabsorption and potassium secretion in the distal convoluted tubule and the connecting tubule (CNT) are sufficient to maintain the sodium and potassium balance, with little or no contribution of the collecting duct. The homeostatic role of the sodium and potassium transport systems in the collecting duct can be questioned, especially in conditions where dietary sodium intake is high and potassium intake is low compared with the physiological needs of the organism. The functional expression of epithelial sodium channels (ENaC) in the CNT is sufficient for furosemide-stimulated urinary acidification and identifies the CNT as a major segment in electrogenic urinary acidification. In the outer renal cortex, the CNT returns to the glomerular hilus and contacts the renal afferent arterioles (Af-Art). This morphology is compatible with a cross-talk between the CNT and Af-Art. This novel regulatory mechanism of the renal microcirculation may participate in the vasodilatation observed during high salt intake, perhaps by antagonizing tubuloglomerular feedback. In conclusion, the cortical distal nephron appears to be a complex site for several physiological mechanisms; it is mainly involved in salt and fluid homeostasis and in acid-base balance maintenance. Furthermore, the CNT segment appears to promote a CNT-Af-Art feedback loop.

  10. Physiologically Relevant Prosthetic Limb Movement Feedback for Upper and Lower Extremity Amputees

    Science.gov (United States)

    2016-10-01

    upper arm (elbow movement), Upper leg (knee movement) and lower leg ( ankle movement) to provide a physiologically relevant sense of limb movement...Additionally a BOA cable tensioning system is passed through these plates and anchored to the external surface of the socket. When tension is applied the

  11. Capillary response to skeletal muscle contraction: evidence that redundancy between vasodilators is physiologically relevant during active hyperaemia.

    Science.gov (United States)

    Lamb, Iain R; Novielli, Nicole M; Murrant, Coral L

    2018-04-15

    The current theory behind matching blood flow to metabolic demand of skeletal muscle suggests redundant interactions between metabolic vasodilators. Capillaries play an important role in blood flow control given their ability to respond to muscle contraction by causing conducted vasodilatation in upstream arterioles that control their perfusion. We sought to determine whether redundancies occur between vasodilators at the level of the capillary by stimulating the capillaries with muscle contraction and vasodilators relevant to muscle contraction. We identified redundancies between potassium and both adenosine and nitric oxide, between nitric oxide and potassium, and between adenosine and both potassium and nitric oxide. During muscle contraction, we demonstrate redundancies between potassium and nitric oxide as well as between potassium and adenosine. Our data show that redundancy is physiologically relevant and involved in the coordination of the vasodilator response during muscle contraction at the level of the capillaries. We sought to determine if redundancy between vasodilators is physiologically relevant during active hyperaemia. As inhibitory interactions between vasodilators are indicative of redundancy, we tested whether vasodilators implicated in mediating active hyperaemia (potassium (K + ), adenosine (ADO) and nitric oxide (NO)) inhibit one another's vasodilatory effects through direct application of pharmacological agents and during muscle contraction. Using the hamster cremaster muscle and intravital microscopy, we locally stimulated capillaries with one vasodilator in the absence and the presence of a second vasodilator (10 -7 m S-nitroso-N-acetylpenicillamine (SNAP), 10 -7 m ADO, 10 mm KCl) applied sequentially and simultaneously, and observed the response in the associated upstream 4A arteriole controlling the perfusion of the stimulated capillary. We found that KCl significantly attenuated SNAP- and ADO-induced vasodilatations by ∼49.7% and

  12. Fluid mechanics relevant to flow through pretreatment of cellulosic biomass.

    Science.gov (United States)

    Archambault-Léger, Véronique; Lynd, Lee R

    2014-04-01

    The present study investigates fluid mechanical properties of cellulosic feedstocks relevant to flow through (FT) pretreatment for biological conversion of cellulosic biomass. The results inform identifying conditions for which FT pretreatment can be implemented in a practical context. Measurements of pressure drop across packed beds, viscous compaction and water absorption are reported for milled and not milled sugarcane bagasse, switchgrass and poplar, and important factors impacting viscous flow are deduced. Using biomass knife-milled to pass through a 2mm sieve, the observed pressure drop was highest for bagasse, intermediate for switchgrass and lowest for poplar. The highest pressure drop was associated with the presence of more fine particles, greater viscous compaction and the degree of water absorption. Using bagasse without particle size reduction, the instability of the reactor during pretreatment above 140kg/m(3) sets an upper bound on the allowable concentration for continuous stable flow. Copyright © 2014. Published by Elsevier Ltd.

  13. The Creation and Physiological Relevance of Divergent Hydroxylation Patterns in the Flavonoid Pathway

    Directory of Open Access Journals (Sweden)

    Heidi Halbwirth

    2010-02-01

    Full Text Available Flavonoids and biochemically-related chalcones are important secondary metabolites, which are ubiquitously present in plants and therefore also in human food. They fulfill a broad range of physiological functions in planta and there are numerous reports about their physiological relevance for humans. Flavonoids have in common a basic C6-C3-C6 skeleton structure consisting of two aromatic rings (A and B and a heterocyclic ring (C containing one oxygen atom, whereas chalcones, as the intermediates in the formation of flavonoids, have not yet established the heterocyclic C-ring. Flavonoids are grouped into eight different classes, according to the oxidative status of the C-ring. The large number of divergent chalcones and flavonoid structures is from the extensive modification of the basic molecules. The hydroxylation pattern influences physiological properties such as light absorption and antioxidative activity, which is the base for many beneficial health effects of flavonoids. In some cases antiinfective properties are also effected.

  14. Macroscale hydrologic modeling of ecologically relevant flow metrics

    Science.gov (United States)

    Wenger, Seth J.; Luce, Charles H.; Hamlet, Alan F.; Isaak, Daniel J.; Neville, Helen M.

    2010-09-01

    Stream hydrology strongly affects the structure of aquatic communities. Changes to air temperature and precipitation driven by increased greenhouse gas concentrations are shifting timing and volume of streamflows potentially affecting these communities. The variable infiltration capacity (VIC) macroscale hydrologic model has been employed at regional scales to describe and forecast hydrologic changes but has been calibrated and applied mainly to large rivers. An important question is how well VIC runoff simulations serve to answer questions about hydrologic changes in smaller streams, which are important habitat for many fish species. To answer this question, we aggregated gridded VIC outputs within the drainage basins of 55 streamflow gages in the Pacific Northwest United States and compared modeled hydrographs and summary metrics to observations. For most streams, several ecologically relevant aspects of the hydrologic regime were accurately modeled, including center of flow timing, mean annual and summer flows and frequency of winter floods. Frequencies of high and low flows in the summer were not well predicted, however. Predictions were worse for sites with strong groundwater influence, and some sites showed errors that may result from limitations in the forcing climate data. Higher resolution (1/16th degree) modeling provided small improvements over lower resolution (1/8th degree). Despite some limitations, the VIC model appears capable of representing several ecologically relevant hydrologic characteristics in streams, making it a useful tool for understanding the effects of hydrology in delimiting species distributions and predicting the potential effects of climate shifts on aquatic organisms.

  15. Social aggravation: Understanding the complex role of social relationships on stress and health-relevant physiology.

    Science.gov (United States)

    Birmingham, Wendy C; Holt-Lunstad, Julianne

    2018-04-05

    There is a rich literature on social support and physical health, but research has focused primarily on the protective effects of social relationship. The stress buffering model asserts that relationships may be protective by being a source of support when coping with stress, thereby blunting health relevant physiological responses. Research also indicates relationships can be a source of stress, also influencing health. In other words, the social buffering influence may have a counterpart, a social aggravating influence that has an opposite or opposing effect. Drawing upon existing conceptual models, we expand these to delineate how social relationships may influence stress processes and ultimately health. This review summarizes the existing literature that points to the potential deleterious physiological effects of our relationships when they are sources of stress or exacerbate stress. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Physiological techniques for detecting expiratory flow limitation during tidal breathing

    Directory of Open Access Journals (Sweden)

    N.G. Koulouris

    2011-09-01

    Full Text Available Patients with severe chronic obstructive pulmonary disease (COPD often exhale along the same flow–volume curve during quiet breathing as they do during the forced expiratory vital capacity manoeuvre, and this has been taken as an indicator of expiratory flow limitation at rest (EFLT. Therefore, EFLT, namely attainment of maximal expiratory flow during tidal expiration, occurs when an increase in transpulmonary pressure causes no increase in expiratory flow. EFLT leads to small airway injury and promotes dynamic pulmonary hyperinflation, with concurrent dyspnoea and exercise limitation. In fact, EFLT occurs commonly in COPD patients (mainly in Global Initiative for Chronic Obstructive Lung Disease III and IV stage, in whom the latter symptoms are common, but is not exclusive to COPD, since it can also be detected in other pulmonary and nonpulmonary diseases like asthma, acute respiratory distress syndrome, heart failure and obesity, etc. The existing up to date physiological techniques of assessing EFLT are reviewed in the present work. Among the currently available techniques, the negative expiratory pressure has been validated in a wide variety of settings and disorders. Consequently, it should be regarded as a simple, noninvasive, practical and accurate new technique.

  17. Do infants find snakes aversive? Infants' physiological responses to "fear-relevant" stimuli.

    Science.gov (United States)

    Thrasher, Cat; LoBue, Vanessa

    2016-02-01

    In the current research, we sought to measure infants' physiological responses to snakes-one of the world's most widely feared stimuli-to examine whether they find snakes aversive or merely attention grabbing. Using a similar method to DeLoache and LoBue (Developmental Science, 2009, Vol. 12, pp. 201-207), 6- to 9-month-olds watched a series of multimodal (both auditory and visual) stimuli: a video of a snake (fear-relevant) or an elephant (non-fear-relevant) paired with either a fearful or happy auditory track. We measured physiological responses to the pairs of stimuli, including startle magnitude, latency to startle, and heart rate. Results suggest that snakes capture infants' attention; infants showed the fastest startle responses and lowest average heart rate to the snakes, especially when paired with a fearful voice. Unexpectedly, they also showed significantly reduced startle magnitude during this same snake video plus fearful voice combination. The results are discussed with respect to theoretical perspectives on fear acquisition. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Flow cytometric fingerprinting for microbial strain discrimination and physiological characterization.

    Science.gov (United States)

    Buysschaert, Benjamin; Kerckhof, Frederiek-Maarten; Vandamme, Peter; De Baets, Bernard; Boon, Nico

    2018-02-01

    The analysis of microbial populations is fundamental, not only for developing a deeper understanding of microbial communities but also for their engineering in biotechnological applications. Many methods have been developed to study their characteristics and over the last few decades, molecular analysis tools, such as DNA sequencing, have been used with considerable success to identify the composition of microbial populations. Recently, flow cytometric fingerprinting is emerging as a promising and powerful method to analyze bacterial populations. So far, these methods have primarily been used to observe shifts in the composition of microbial communities of natural samples. In this article, we apply a flow cytometric fingerprinting method to discriminate among 29 Lactobacillus strains. Our results indicate that it is possible to discriminate among 27 Lactobacillus strains by staining with SYBR green I and that the discriminatory power can be increased by combined SYBR green I and propidium iodide staining. Furthermore, we illustrate the impact of physiological changes on the fingerprinting method by demonstrating how flow cytometric fingerprinting is able to discriminate the different growth phases of a microbial culture. The sensitivity of the method is assessed by its ability to detect changes in the relative abundance of a mix of polystyrene beads down to 1.2%. When a mix of bacteria was used, the sensitivity was as between 1.2% and 5%. The presented data demonstrate that flow cytometric fingerprinting is a sensitive and reproducible technique with the potential to be applied as a method for the dereplication of bacterial isolates. © 2017 International Society for Advancement of Cytometry. © 2017 International Society for Advancement of Cytometry.

  19. Organismal climatology: analyzing environmental variability at scales relevant to physiological stress.

    Science.gov (United States)

    Helmuth, Brian; Broitman, Bernardo R; Yamane, Lauren; Gilman, Sarah E; Mach, Katharine; Mislan, K A S; Denny, Mark W

    2010-03-15

    Predicting when, where and with what magnitude climate change is likely to affect the fitness, abundance and distribution of organisms and the functioning of ecosystems has emerged as a high priority for scientists and resource managers. However, even in cases where we have detailed knowledge of current species' range boundaries, we often do not understand what, if any, aspects of weather and climate act to set these limits. This shortcoming significantly curtails our capacity to predict potential future range shifts in response to climate change, especially since the factors that set range boundaries under those novel conditions may be different from those that set limits today. We quantitatively examine a nine-year time series of temperature records relevant to the body temperatures of intertidal mussels as measured using biomimetic sensors. Specifically, we explore how a 'climatology' of body temperatures, as opposed to long-term records of habitat-level parameters such as air and water temperatures, can be used to extrapolate meaningful spatial and temporal patterns of physiological stress. Using different metrics that correspond to various aspects of physiological stress (seasonal means, cumulative temperature and the return time of extremes) we show that these potential environmental stressors do not always occur in synchrony with one another. Our analysis also shows that patterns of animal temperature are not well correlated with simple, commonly used metrics such as air temperature. Detailed physiological studies can provide guidance to predicting the effects of global climate change on natural ecosystems but only if we concomitantly record, archive and model environmental signals at appropriate scales.

  20. Physiological relevance of plant 2-Cys peroxiredoxin overoxidation level and oligomerization status.

    Science.gov (United States)

    Cerveau, Delphine; Ouahrani, Djelloul; Marok, Mohamed Amine; Blanchard, Laurence; Rey, Pascal

    2016-01-01

    Peroxiredoxins are ubiquitous thioredoxin-dependent peroxidases presumed to display, upon environmental constraints, a chaperone function resulting from a redox-dependent conformational switch. In this work, using biochemical and genetic approaches, we aimed to unravel the factors regulating the redox status and the conformation of the plastidial 2-Cys peroxiredoxin (2-Cys PRX) in plants. In Arabidopsis, we show that in optimal growth conditions, the overoxidation level mainly depends on the availability of thioredoxin-related electron donors, but not on sulfiredoxin, the enzyme reducing the 2-Cys PRX overoxidized form. We also observed that upon various physiological temperature, osmotic and light stress conditions, the overoxidation level and oligomerization status of 2-Cys PRX can moderately vary depending on the constraint type. Further, no major change was noticed regarding protein conformation in water-stressed Arabidopsis, barley and potato plants, whereas species-dependent up- and down-variations in overoxidation were observed. In contrast, both 2-Cys PRX overoxidation and oligomerization were strongly induced during a severe oxidative stress generated by methyl viologen. From these data, revealing that the oligomerization status of plant 2-Cys PRX does not exhibit important variation and is not tightly linked to the protein redox status upon physiologically relevant environmental constraints, the possible in planta functions of 2-Cys PRX are discussed. © 2015 John Wiley & Sons Ltd.

  1. Bayesian Population Physiologically-Based Pharmacokinetic (PBPK Approach for a Physiologically Realistic Characterization of Interindividual Variability in Clinically Relevant Populations.

    Directory of Open Access Journals (Sweden)

    Markus Krauss

    Full Text Available Interindividual variability in anatomical and physiological properties results in significant differences in drug pharmacokinetics. The consideration of such pharmacokinetic variability supports optimal drug efficacy and safety for each single individual, e.g. by identification of individual-specific dosings. One clear objective in clinical drug development is therefore a thorough characterization of the physiological sources of interindividual variability. In this work, we present a Bayesian population physiologically-based pharmacokinetic (PBPK approach for the mechanistically and physiologically realistic identification of interindividual variability. The consideration of a generic and highly detailed mechanistic PBPK model structure enables the integration of large amounts of prior physiological knowledge, which is then updated with new experimental data in a Bayesian framework. A covariate model integrates known relationships of physiological parameters to age, gender and body height. We further provide a framework for estimation of the a posteriori parameter dependency structure at the population level. The approach is demonstrated considering a cohort of healthy individuals and theophylline as an application example. The variability and co-variability of physiological parameters are specified within the population; respectively. Significant correlations are identified between population parameters and are applied for individual- and population-specific visual predictive checks of the pharmacokinetic behavior, which leads to improved results compared to present population approaches. In the future, the integration of a generic PBPK model into an hierarchical approach allows for extrapolations to other populations or drugs, while the Bayesian paradigm allows for an iterative application of the approach and thereby a continuous updating of physiological knowledge with new data. This will facilitate decision making e.g. from preclinical to

  2. Basics and principles of particle image velocimetry (PIV) for mapping biogenic and biologically relevant flows

    NARCIS (Netherlands)

    Stamhuis, Eize J.

    2006-01-01

    Particle image velocimetry (PIV) has proven to be a very useful technique in mapping animal-generated flows or flow patterns relevant to biota. Here, theoretical background is provided and experimental details of 2-dimensional digital PIV are explained for mapping flow produced by or relevant to

  3. A molecular hybrid polyoxometalate-organometallic moieties and its relevance to supercapacitors in physiological electrolytes

    Science.gov (United States)

    Chinnathambi, Selvaraj; Ammam, Malika

    2015-06-01

    Supercapacitors operating in physiological electrolytes are of great relevance for both their environmentally friendly aspect as well as the possibility to be employed for powering implantable microelectronic devices using directly biological fluids as electrolytes. Polyoxometalate (POMs) have been proven to be useful for supercapacitors in acidic media. However, in neutral pH, POMs are usually not stable. One relevant alternative is to stabilize POMs by pairing them with organic moieties to form hybrids. In this study, we combined K6P2Mo18O62·12H2O (P2Mo18) with Ru(bpy)3Cl2.6H2O (Ru(bpy)). The synthesis was carried out with and without the mild reducing agent KI. The hybrids were characterized by CHN analysis, TEM, FT-IR, XRD, TGA and cyclic voltammetry. CHN elemental analysis revealed that one mole [P2Mo18O62]6- is paired with 3 mol [Ru(bpy)3]2+ to form [Ru(bpy)3]3PMo18O62·nH2O. With KI present, [P2Mo18O62]6- is linked to 3.33 mol to yield [Ru(bpy)3]3.33PMo18O62·mH2O. Excess of Ru(bpy) in [Ru(bpy)3]3.33PMo18O62·mH2O was further confirmed by TEM, FT-IR, XRD, TGA and cyclic voltammetry. In turn, hybrid composition is found to strongly influence the supercapacitor behavior. The hybrid rich in Ru(bpy) is found to perform better for supercapacitors in physiological electrolytes. 125 F g-1 and 68 F g-1 are the capacitance values obtained with [Ru(bpy)3]3.33PMo18O62·mH2O and [Ru(bpy)3]3PMo18O62·nH2O, respectively. In terms of specific energy densities, 3.5 Wh kg-1 and 2 Wh kg-1 were obtained for both hybrid simultaneously. The difference in supercapacitor performance between both hybrids is also noticed in impedance spectroscopy which showed that [Ru(bpy)3]3.33PMo18O62·mH2O has lower electron transfer resistance if compared to [Ru(bpy)3]3PMo18O62·nH2O. Finally, if compared of parent K6P2Mo18O62·12H2O, the stability of both hybrids is found to be highly improved.

  4. General concepts of ventricular function, Myocardial perfusion, and exercise physiology relevant to nuclear cardiology

    International Nuclear Information System (INIS)

    Kronenberg, M.W.; Becker, L.C.

    1988-01-01

    Knowledge of ventricular mechanics, the physiology of the coronary circulation, and exercise physiology is necessary for the accurate interpretation of radionuclide ventriculographic and myocardial perfusion images. This chapter outlines these important basic concepts as applied to the whole heart

  5. Animal thermoregulation: a review of insulation, physiology and behaviour relevant to temperature control in buildings.

    Science.gov (United States)

    McCafferty, D J; Pandraud, G; Gilles, J; Fabra-Puchol, M; Henry, P-Y

    2017-12-28

    Birds and mammals have evolved many thermal adaptations that are relevant to the bioinspired design of temperature control systems and energy management in buildings. Similar to many buildings, endothermic animals generate internal metabolic heat, are well insulated, regulate their temperature within set limits, modify microclimate and adjust thermal exchange with their environment. We review the major components of animal thermoregulation in endothermic birds and mammals that are pertinent to building engineering, in a world where climate is changing and reduction in energy use is needed. In animals, adjustment of insulation together with physiological and behavioural responses to changing environmental conditions fine-tune spatial and temporal regulation of body temperature, while also minimizing energy expenditure. These biological adaptations are characteristically flexible, allowing animals to alter their body temperatures to hourly, daily, or annual demands for energy. They exemplify how buildings could become more thermally reactive to meteorological fluctuations, capitalising on dynamic thermal materials and system properties. Based on this synthesis, we suggest that heat transfer modelling could be used to simulate these flexible biomimetic features and assess their success in reducing energy costs while maintaining thermal comfort for given building types.

  6. Interface tracking simulations of bubbly flows in PWR relevant geometries

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Jun, E-mail: jfang3@ncsu.edu [Department of Nuclear Engineering, North Carolina State University, Raleigh, NC 27695 (United States); Rasquin, Michel, E-mail: michel.rasquin@colorado.edu [Aerospace Engineering Department, University of Colorado, Boulder, CO 80309 (United States); Bolotnov, Igor A., E-mail: igor_bolotnov@ncsu.edu [Department of Nuclear Engineering, North Carolina State University, Raleigh, NC 27695 (United States)

    2017-02-15

    Highlights: • Simulations were performed for turbulent bubbly flows in PWR subchannel geometry. • Liquid turbulence is fully resolved by direct numerical simulation approach. • Bubble behavior is captured using level-set interface tracking method. • Time-averaged single- and two-phase turbulent flow statistical quantities are obtained. - Abstract: The advances in high performance computing (HPC) have allowed direct numerical simulation (DNS) approach coupled with interface tracking methods (ITM) to perform high fidelity simulations of turbulent bubbly flows in various complex geometries. In this work, we have chosen the geometry of the pressurized water reactor (PWR) core subchannel to perform a set of interface tracking simulations (ITS) with fully resolved liquid turbulence. The presented research utilizes a massively parallel finite-element based code, PHASTA, for the subchannel geometry simulations of bubbly flow turbulence. The main objective for this research is to demonstrate the ITS capabilities in gaining new insight into bubble/turbulence interactions and assisting the development of improved closure laws for multiphase computational fluid dynamics (M-CFD). Both single- and two-phase turbulent flows were studied within a single PWR subchannel. The analysis of numerical results includes the mean gas and liquid velocity profiles, void fraction distribution and turbulent kinetic energy profiles. Two sets of flow rates and bubble sizes were used in the simulations. The chosen flow rates corresponded to the Reynolds numbers of 29,079 and 80,775 based on channel hydraulic diameter (D{sub h}) and mean velocity. The finite element unstructured grids utilized for these simulations include 53.8 million and 1.11 billion elements, respectively. This has allowed to fully resolve all the turbulence scales and the deformable interfaces of individual bubbles. For the two-phase flow simulations, a 1% bubble volume fraction was used which resulted in 17 bubbles in

  7. Characterization of a second physiologically relevant lactose permease gene (lacpB) in Aspergillus nidulans.

    Science.gov (United States)

    Fekete, Erzsébet; Orosz, Anita; Kulcsár, László; Kavalecz, Napsugár; Flipphi, Michel; Karaffa, Levente

    2016-05-01

    In Aspergillus nidulans, uptake rather than hydrolysis is the rate-limiting step of lactose catabolism. Deletion of the lactose permease A-encoding gene (lacpA) reduces the growth rate on lactose, while its overexpression enables faster growth than wild-type strains are capable of. We have identified a second physiologically relevant lactose transporter, LacpB. Glycerol-grown mycelia from mutants deleted for lacpB appear to take up only minute amounts of lactose during the first 60 h after a medium transfer, while mycelia of double lacpA/lacpB-deletant strains are unable to produce new biomass from lactose. Although transcription of both lacp genes was strongly induced by lactose, their inducer profiles differ markedly. lacpA but not lacpB expression was high in d-galactose cultures. However, lacpB responded strongly also to β-linked glucopyranose dimers cellobiose and sophorose, while these inducers of the cellulolytic system did not provoke any lacpA response. Nevertheless, lacpB transcript was induced to higher levels on cellobiose in strains that lack the lacpA gene than in a wild-type background. Indeed, cellobiose uptake was faster and biomass formation accelerated in lacpA deletants. In contrast, in lacpB knockout strains, growth rate and cellobiose uptake were considerably reduced relative to wild-type, indicating that the cellulose and lactose catabolic systems employ common elements. Nevertheless, our permease mutants still grew on cellobiose, which suggests that its uptake in A. nidulans prominently involves hitherto unknown transport systems.

  8. The effect of folate status on the uptake of physiologically relevant compounds by Caco-2 cells.

    Science.gov (United States)

    Tavares, Sandra; Sousa, Joana; Gonçalves, Pedro; Araújo, João R; Martel, Fátima

    2010-08-25

    The aim of this work was to investigate the effect of folate status on the uptake of several physiologically relevant substances by Caco-2 cells. For this, Caco-2 cells cultured in high-folate conditions (HF) and low-folate conditions (LF) were compared. Growth rates of HF and LF Caco-2 cells were similar. However, proliferation rate of LF cells was greater than that of HF cells during the first 2days of culture and slightly smaller thereafter, viability of LF cells was greater than that of HF cells, and apoptosis index was similar in both cell cultures. We verified that in LF cells, comparatively to HF cells: (1) uptake of [3H]folic acid is upregulated, via an increase in the Vmax of uptake; (2) uptake of [3H]deoxy-glucose, [3H]O-methyl-glucose and [3H]1-methyl-4-phenylpyridinium (MPP+) is downregulated, via a decrease in the Vmax of uptake; additionally, a reduction in Km was observed for [3H]O-methyl-glucose; (3) uptake of [3H]5-hydroxytryptamine and [14C]butyrate is not changed; and (4) the steady-state mRNA levels of the folic acid transporters RFC (reduced folate carrier), PCFT (proton-coupled folate transporter) and FRalpha (folate receptor alpha), of the organic cation transporter OCT1 (organic cation transporter type 1), of the glucose transporter GLUT2 (facilitative glucose transporter type 2) and of the butyrate transporter MCT1 (monocarboxylate transporter type 1) were decreased. In conclusion, folate deficiency produces substrate-specific changes in the uptake of bioactive compounds by Caco-2 cells. Moreover, these changes are associated with alterations in the mRNA levels of specific transporters for these compounds. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  9. Elucidating Dynamical Processes Relevant to Flow Encountering Abrupt Topography (FLEAT)

    Science.gov (United States)

    2015-09-30

    Encountering Abrupt Topography (FLEAT) Bo Qiu Dept of Oceanography, University of Hawaii at Manoa 1000 Pope Rd. Honolulu, HI 96822 phone: (808) 956...c) to explore relevant dynamics by using both simplified models and OGCM output with realistic topography and surface boundary conditions...scale abyssal circulation, we propose to use the Hallberg Isopycnal Model (HIM). The HIM allows sloping isopycnals to interact with bottom topography

  10. The value relevance of direct cash flows under international financial reporting standards

    OpenAIRE

    Clacher, I; de Ricquebourg, AD; Hodgson, A

    2013-01-01

    This study examines if there has been a change in the value relevance of direct cash flow components since the adoption of International Financial Reporting Standards (IFRS) in Australia. Our results show that for both industrial and extractive firms direct cash flow statements are value relevant under Australian Generally Accepted Accounting Principles (AGAAP) and remain so after the adoption of IFRS. In addition, for industrial firms there is a significant increase in the value relevance of...

  11. Flow and oscillations in collapsible tubes: Physiological applications ...

    Indian Academy of Sciences (India)

    pressure changes associated with fluid flow in the tube may be enough to generate large area changes. Collapsible ... As a very simple model, consider a single, uniform pipe containing viscous fluid flowing steadily at volume ..... (1986). For each mode the instability occurs through a Hopf bifurcation, which is supercritical.

  12. Modeling skin blood flow: a neuro-physiological approach

    NARCIS (Netherlands)

    Kingma, B.R.M.; Saris, W.H.M.; Frijns, A.J.H.; Steenhoven, van A.A.; Marken Lichtenbelt, van W.D.

    2010-01-01

    In humans skin blood flow (SBF) plays a major role in body heat loss. Therefore the accuracy of models ofhuman thermoregulation depends for a great deal on their ability to predict skin blood flow. Most SBFmodelsuse body temperatures directly for calculation of skin perfusion. However, humans do not

  13. Dual Atrioventricular Nodal Pathways Physiology: A Review of Relevant Anatomy, Electrophysiology, and Electrocardiographic Manifestations

    Directory of Open Access Journals (Sweden)

    Bhalaghuru Chokkalingam Mani, MD

    2014-01-01

    Full Text Available More than half a century has passed since the concept of dual atrioventricular (AV nodal pathways physiology was conceived. Dual AV nodal pathways have been shown to be responsible for many clinical arrhythmia syndromes, most notably AV nodal reentrant tachycardia. Although there has been a considerable amount of research on this topic, the subject of dual AV nodal pathways physiology remains heavily debated and discussed. Despite advances in understanding arrhythmia mechanisms and the widespread use of invasive electrophysiologic studies, there is still disagreement on the anatomy and physiology of the AV node that is the basis of discontinuous antegrade AV conduction. The purpose of this paper is to review the concept of dual AV nodal pathways physiology and its varied electrocardiographic manifestations.

  14. Diving physiology of seabirds and marine mammals: Relevance, challenges and some solutions for field studies.

    Science.gov (United States)

    Andrews, Russel D; Enstipp, Manfred R

    2016-12-01

    To fully understand how diving seabirds and marine mammals balance the potentially conflicting demands of holding their breath while living their lives underwater (and maintaining physiological homeostasis during exercise, feeding, growth, and reproduction), physiological studies must be conducted with animals in their natural environments. The purpose of this article is to review the importance of making physiological measurements on diving animals in field settings, while acknowledging the challenges and highlighting some solutions. The most extreme divers are great candidates for study, especially in a comparative and mechanistic context. However, physiological data are also required of a wide range of species for problems relating to other disciplines, in particular ecology and conservation biology. Physiological data help with understanding and predicting the outcomes of environmental change, and the direct impacts of anthropogenic activities. Methodological approaches that have facilitated the development of field-based diving physiology include the isolated diving hole protocol and the translocation paradigm, and while there are many techniques for remote observation, animal-borne biotelemetry, or "biologging", has been critical. We discuss issues related to the attachment of instruments, the retrieval of data and sensing of physiological variables, while also considering negative impacts of tagging. This is illustrated with examples from a variety of species, and an in-depth look at one of the best studied and most extreme divers, the emperor penguin (Aptenodytes forsteri). With a variety of approaches and high demand for data on the physiology of diving seabirds and marine mammals, the future of field studies is bright. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Thermoregulatory responses in exercising rats: methodological aspects and relevance to human physiology.

    Science.gov (United States)

    Wanner, Samuel Penna; Prímola-Gomes, Thales Nicolau; Pires, Washington; Guimarães, Juliana Bohnen; Hudson, Alexandre Sérvulo Ribeiro; Kunstetter, Ana Cançado; Fonseca, Cletiana Gonçalves; Drummond, Lucas Rios; Damasceno, William Coutinho; Teixeira-Coelho, Francisco

    2015-01-01

    Rats are used worldwide in experiments that aim to investigate the physiological responses induced by a physical exercise session. Changes in body temperature regulation, which may affect both the performance and the health of exercising rats, are evident among these physiological responses. Despite the universal use of rats in biomedical research involving exercise, investigators often overlook important methodological issues that hamper the accurate measurement of clear thermoregulatory responses. Moreover, much debate exists regarding whether the outcome of rat experiments can be extrapolated to human physiology, including thermal physiology. Herein, we described the impact of different exercise intensities, durations and protocols and environmental conditions on running-induced thermoregulatory changes. We focused on treadmill running because this type of exercise allows for precise control of the exercise intensity and the measurement of autonomic thermoeffectors associated with heat production and loss. Some methodological issues regarding rat experiments, such as the sites for body temperature measurements and the time of day at which experiments are performed, were also discussed. In addition, we analyzed the influence of a high body surface area-to-mass ratio and limited evaporative cooling on the exercise-induced thermoregulatory responses of running rats and then compared these responses in rats to those observed in humans. Collectively, the data presented in this review represent a reference source for investigators interested in studying exercise thermoregulation in rats. In addition, the present data indicate that the thermoregulatory responses of exercising rats can be extrapolated, with some important limitations, to human thermal physiology.

  16. Development of a novel, physiologically relevant cytotoxicity model: Application to the study of chemotherapeutic damage to mesenchymal stromal cells

    Energy Technology Data Exchange (ETDEWEB)

    May, Jennifer E., E-mail: Jennifer2.May@uwe.ac.uk; Morse, H. Ruth, E-mail: Ruth.Morse@uwe.ac.uk; Xu, Jinsheng, E-mail: Jinsheng.Xu@uwe.ac.uk; Donaldson, Craig, E-mail: Craig.Donaldson@uwe.ac.uk

    2012-09-15

    There is an increasing need for development of physiologically relevant in-vitro models for testing toxicity, however determining toxic effects of agents which undergo extensive hepatic metabolism can be particularly challenging. If a source of such metabolic enzymes is inadequate within a model system, toxicity from prodrugs may be grossly underestimated. Conversely, the vast majority of agents are detoxified by the liver, consequently toxicity from such agents may be overestimated. In this study we describe the development of a novel in-vitro model, which could be adapted for any toxicology setting. The model utilises HepG2 liver spheroids as a source of metabolic enzymes, which have been shown to more closely resemble human liver than traditional monolayer cultures. A co-culture model has been developed enabling the effect of any metabolised agent on another cell type to be assessed. This has been optimised to enable the study of damaging effects of chemotherapy on mesenchymal stem cells (MSC), the supportive stem cells of the bone marrow. Several optimisation steps were undertaken, including determining optimal culture conditions, confirmation of hepatic P450 enzyme activity and ensuring physiologically relevant doses of chemotherapeutic agents were appropriate for use within the model. The developed model was subsequently validated using several chemotherapeutic agents, both prodrugs and active drugs, with resulting MSC damage closely resembling effects seen in patients following chemotherapy. Minimal modifications would enable this novel co-culture model to be utilised as a general toxicity model, contributing to the drive to reduce animal safety testing and enabling physiologically relevant in-vitro study. -- Highlights: ► An in vitro model was developed for study of drugs requiring hepatic metabolism ► HepG2 spheroids were utilised as a physiologically relevant source of liver enzymes ► The model was optimised to enable study of chemotherapeutic

  17. Development of a novel, physiologically relevant cytotoxicity model: Application to the study of chemotherapeutic damage to mesenchymal stromal cells

    International Nuclear Information System (INIS)

    May, Jennifer E.; Morse, H. Ruth; Xu, Jinsheng; Donaldson, Craig

    2012-01-01

    There is an increasing need for development of physiologically relevant in-vitro models for testing toxicity, however determining toxic effects of agents which undergo extensive hepatic metabolism can be particularly challenging. If a source of such metabolic enzymes is inadequate within a model system, toxicity from prodrugs may be grossly underestimated. Conversely, the vast majority of agents are detoxified by the liver, consequently toxicity from such agents may be overestimated. In this study we describe the development of a novel in-vitro model, which could be adapted for any toxicology setting. The model utilises HepG2 liver spheroids as a source of metabolic enzymes, which have been shown to more closely resemble human liver than traditional monolayer cultures. A co-culture model has been developed enabling the effect of any metabolised agent on another cell type to be assessed. This has been optimised to enable the study of damaging effects of chemotherapy on mesenchymal stem cells (MSC), the supportive stem cells of the bone marrow. Several optimisation steps were undertaken, including determining optimal culture conditions, confirmation of hepatic P450 enzyme activity and ensuring physiologically relevant doses of chemotherapeutic agents were appropriate for use within the model. The developed model was subsequently validated using several chemotherapeutic agents, both prodrugs and active drugs, with resulting MSC damage closely resembling effects seen in patients following chemotherapy. Minimal modifications would enable this novel co-culture model to be utilised as a general toxicity model, contributing to the drive to reduce animal safety testing and enabling physiologically relevant in-vitro study. -- Highlights: ► An in vitro model was developed for study of drugs requiring hepatic metabolism ► HepG2 spheroids were utilised as a physiologically relevant source of liver enzymes ► The model was optimised to enable study of chemotherapeutic

  18. A physiologically-based pharmacokinetic(PB-PK) model for ethylene dibromide : relevance of extrahepatic metabolism

    NARCIS (Netherlands)

    Hissink, A M; Wormhoudt, L.W.; Sherratt, P.J.; Hayes, D.J.; Commandeur, J N; Vermeulen, N P; van Bladeren, P.J.

    A physiologically-based pharmacokinetic (PB-PK) model was developed for ethylene dibromide (1,2-dibromoethane, EDB) for rats and humans, partly based on previously published in vitro data (Ploemen et al., 1997). In the present study, this PB-PK model has been validated for the rat. In addition, new

  19. A physiologically-based pharmacokinetic (PB-PK) model for ethylene dibromide : relevance of extrahepatic metabolism

    NARCIS (Netherlands)

    Hissink, A.M.; Wormhoudt, L.W.; Sherratt, P.J.; Hayes, J.D.; Commandeur, J.N.M.; Vermeulen, N.P.E.; Bladeren, P.J. van

    2000-01-01

    A physiologically-based pharmacokinetic (PB-PK) model was developed for ethylene dibromide (1,2-dibromoethane, EDB) for rats and humans, partly based on previously published in vitro data (Ploemen et al., 1997). In the present study, this PB-PK model has been validated for the rat. In addition, new

  20. GPR68 Senses Flow and Is Essential for Vascular Physiology.

    Science.gov (United States)

    Xu, Jie; Mathur, Jayanti; Vessières, Emilie; Hammack, Scott; Nonomura, Keiko; Favre, Julie; Grimaud, Linda; Petrus, Matt; Francisco, Allain; Li, Jingyuan; Lee, Van; Xiang, Fu-Li; Mainquist, James K; Cahalan, Stuart M; Orth, Anthony P; Walker, John R; Ma, Shang; Lukacs, Viktor; Bordone, Laura; Bandell, Michael; Laffitte, Bryan; Xu, Yan; Chien, Shu; Henrion, Daniel; Patapoutian, Ardem

    2018-04-19

    Mechanotransduction plays a crucial role in vascular biology. One example of this is the local regulation of vascular resistance via flow-mediated dilation (FMD). Impairment of this process is a hallmark of endothelial dysfunction and a precursor to a wide array of vascular diseases, such as hypertension and atherosclerosis. Yet the molecules responsible for sensing flow (shear stress) within endothelial cells remain largely unknown. We designed a 384-well screening system that applies shear stress on cultured cells. We identified a mechanosensitive cell line that exhibits shear stress-activated calcium transients, screened a focused RNAi library, and identified GPR68 as necessary and sufficient for shear stress responses. GPR68 is expressed in endothelial cells of small-diameter (resistance) arteries. Importantly, Gpr68-deficient mice display markedly impaired acute FMD and chronic flow-mediated outward remodeling in mesenteric arterioles. Therefore, GPR68 is an essential flow sensor in arteriolar endothelium and is a critical signaling component in cardiovascular pathophysiology. Copyright © 2018 Elsevier Inc. All rights reserved.

  1. Manipulation of in vitro collagen matrix architecture for scaffolds of improved physiological relevance

    Science.gov (United States)

    Hapach, Lauren A.; VanderBurgh, Jacob A.; Miller, Joseph P.; Reinhart-King, Cynthia A.

    2015-12-01

    Type I collagen is a versatile biomaterial that is widely used in medical applications due to its weak antigenicity, robust biocompatibility, and its ability to be modified for a wide array of applications. As such, collagen has become a major component of many tissue engineering scaffolds, drug delivery platforms, and substrates for in vitro cell culture. In these applications, collagen constructs are fabricated to recapitulate a diverse set of conditions. Collagen fibrils can be aligned during or post-fabrication, cross-linked via numerous techniques, polymerized to create various fibril sizes and densities, and copolymerized into a wide array of composite scaffolds. Here, we review approaches that have been used to tune collagen to better recapitulate physiological environments for use in tissue engineering applications and studies of basic cell behavior. We discuss techniques to control fibril alignment, methods for cross-linking collagen constructs to modulate stiffness, and composite collagen constructs to better mimic physiological extracellular matrix.

  2. Physiologic Pressure and Flow Changes During Parabolic Flight (Pilot Study)

    Science.gov (United States)

    Pantalos, George; Sharp, M. Keith; Mathias, John R.; Hargens, Alan R.; Watenpaugh, Donald E.; Buckey, Jay C.

    1999-01-01

    The objective of this study was to obtain measurement of cutaneous tissue perfusion central and peripheral venous pressure, and esophageal and abdominal pressure in human test subjects during parabolic flight. Hemodynamic data recorded during SLS-I and SLS-2 missions have resulted in the paradoxical finding of increased cardiac stroke volume in the presence of a decreased central venous pressure (CVP) following entry in weightlessness. The investigators have proposed that in the absence of gravity, acceleration-induced peripheral vascular compression is relieved, increasing peripheral vascular capacity and flow while reducing central and peripheral venous pressure, This pilot study seeks to measure blood pressure and flow in human test subjects during parabolic flight for different postures.

  3. An evaluation of the hydrologic relevance of lateral flow in snow at hillslope and catchment scales

    Science.gov (United States)

    David Eiriksson; Michael Whitson; Charles H. Luce; Hans Peter Marshall; John Bradford; Shawn G. Benner; Thomas Black; Hank Hetrick; James P. McNamara

    2013-01-01

    Lateral downslope flow in snow during snowmelt and rain-on-snow (ROS) events is a well-known phenomenon, yet its relevance to water redistribution at hillslope and catchment scales is not well understood. We used dye tracers, geophysical methods, and hydrometric measurements to describe the snow properties that promote lateral flow, assess the relative velocities of...

  4. On the Quantitative Analysis of Liquid Flow in Physiological Tubes.

    Science.gov (United States)

    1982-12-01

    cri- copharyngeal sphincter which is aided by skeletal muscle (Vantrap- pen and hellemans, 1980) relaxes to accept the bolus and the gastro - esophageal ...lower ( gastro -) esophageal junction during peristalsis resulting from the interaction of gastric, esophageal and thoracic pressures. PIP is a pressure...higher than the downstream pressure and a flow velocity profile with no reflux (syn.: retropulsion). The 5 Pumping in Biological Tubes a. Peristaltic

  5. Net Income, Book Value and Cash Flows: The Value Relevance in Jordanian Economic Sectors

    Directory of Open Access Journals (Sweden)

    DHIAA SHAMKI

    2013-07-01

    Full Text Available This paper examines the value relevance of financial statements variables namely net income, book value and cash flows simultaneously relative to Jordanian services and industrial firms for the period from 2000 to 2009. The main findings of this paper are three- dimensional. First, net income is value relevant, while book value and cash flows are irrelevant. Second, net income is more value relevant than book value and cash flows in both sectors. Third, this value relevance is greater in services sector than in industrial sector. The study shows that net income assist more in explaining market values in Jordanian services and industrial firms. Since research on the value relevance of these variables has neglected Jordan (and the Middle Eastern region, the study tries to fill this practical gap. The study is the first in Jordan that examines the value relevance of net income, book value and cash flows simultaneously and compares this value relevance according to Amman Stock Exchange sectors in one study in Jordan.

  6. Keeping the intracellular vitamin C at a physiologically relevant level in endothelial cell culture

    DEFF Research Database (Denmark)

    Frikke-Schmidt, Henriette Rønne; Lykkesfeldt, Jens

    2010-01-01

    It is generally accepted that the addition of vitamin C to cell culture medium improves cell growth. However, once added, the vitamin C concentration declines rapidly. This situation differs from the in vivo environment where the endothelium is constantly supplied with ascorbate from the blood....... With a focus on intracellular vitamin C, we simulated constant supply of ascorbate by the hourly addition of freshly prepared medium containing 75 lM ascorbate and subsequently compared it with more practical regimens using combinations of ascorbate and 2-phosphoascorbate. We found that a single supplement...... of ascorbate and 2-phosphoascorbate adequately maintains intracellular vitamin C at physiological levels for up to 72 h....

  7. Physiological Plasticity to Water Flow Habitat in the Damselfish, Acanthochromis polyacanthus: Linking Phenotype to Performance

    Science.gov (United States)

    Binning, Sandra A.; Ros, Albert F. H.; Nusbaumer, David; Roche, Dominique G.

    2015-01-01

    The relationships among animal form, function and performance are complex, and vary across environments. Therefore, it can be difficult to identify morphological and/or physiological traits responsible for enhancing performance in a given habitat. In fishes, differences in swimming performance across water flow gradients are related to morphological variation among and within species. However, physiological traits related to performance have been less well studied. We experimentally reared juvenile damselfish, Acanthochromis polyacanthus, under different water flow regimes to test 1) whether aspects of swimming physiology and morphology show plastic responses to water flow, 2) whether trait divergence correlates with swimming performance and 3) whether flow environment relates to performance differences observed in wild fish. We found that maximum metabolic rate, aerobic scope and blood haematocrit were higher in wave-reared fish compared to fish reared in low water flow. However, pectoral fin shape, which tends to correlate with sustained swimming performance, did not differ between rearing treatments or collection sites. Maximum metabolic rate was the best overall predictor of individual swimming performance; fin shape and fish total length were 3.3 and 3.7 times less likely than maximum metabolic rate to explain differences in critical swimming speed. Performance differences induced in fish reared in different flow environments were less pronounced than in wild fish but similar in direction. Our results suggest that exposure to water motion induces plastic physiological changes which enhance swimming performance in A. polyacanthus. Thus, functional relationships between fish morphology and performance across flow habitats should also consider differences in physiology. PMID:25807560

  8. Retrieval-time properties of the Little-Hopfield model and their physiological relevance

    International Nuclear Information System (INIS)

    Risau-Gusman, Sebastian; Idiart, Marco A.P.

    2005-01-01

    We perform an extensive numerical investigation on the retrieval dynamics of the synchronous Hopfield model, also known as Little-Hopfield model, up to sizes of 2 18 neurons. Our results correct and extend much of the early simulations on the model. We find that the average convergence time has a power law behavior for a wide range of system sizes, whose exponent depends both on the network loading and the initial overlap with the memory to be retrieved. Surprisingly, we also find that the variance of the convergence time grows as fast as its average, making it a non-self-averaging quantity. Based on the simulation data we differentiate between two definitions for memory retrieval time, one that is mathematically strict, τ c , the number of updates needed to reach the attractor whose properties we just described, and a second definition correspondent to the time τ η when the network stabilizes within a tolerance threshold η such that the difference of two consecutive overlaps with a stored memory is smaller that η. We show that the scaling relationships between τ c and τ η and the typical network parameters as the memory load α or the size of the network N vary greatly, being τ η relatively insensitive to system sizes and loading. We propose τ η as the physiological realistic measure for the typical attractor network response

  9. New Insights into the Surgical Management of Tetralogy of Fallot: Physiological Fundamentals and Clinical Relevance.

    Science.gov (United States)

    Bove, Thierry; François, Katrien; De Wolf, Daniel

    2015-01-01

    The surgical treatment of tetralogy of Fallot can be considered as a success story in the history of congenital heart diseases. Since the early outcome is no longer the main issue, the focus moved to the late sequelae of TOF repair, i.e. the pulmonary insufficiency and the secondary adaptation of the right ventricle. This review provides recent insights into the pathophysiological alterations of the right ventricle in relation to the reconstruction of the right ventricular outflow tract after repair of tetralogy of Fallot. Its clinical relevance is documented by addressing the policy changes regarding the optimal management at the time of surgical repair as well as properly defining criteria and timing for late pulmonary valve implantation.

  10. Comparative study of Newtonian physiological blood flow through normal and stenosed carotid artery

    Science.gov (United States)

    Rahman, Mohammad Matiur; Hossain, Md. Anwar; Mamun, Khairuzzaman; Akhter, Most. Nasrin

    2017-06-01

    A numerical simulation is performed to investigate Newtonian physiological flows behavior on three dimensional idealized carotid artery (CA) and single stenosed (75% by area) carotid artery(SCA). The wall vessel is set as rigid during simulation. Bifurcated blood vessel are simulated by using three-dimensional flow analysis. Physiological and parabolic velocity profiles are set out to fix the conditions of inlet boundaries of artery. In other hand, physiological waveform is an important part of compilation and it is successfully done by utilization of Fourier series having sixteen harmonics. The investigation has a Reynolds number range of 94 to 1120. Low Reynolds number k — ω model has been used as governing equation. The investigation has been carried out to characterize the flow behavior of blood in two geometry, namely, (i) Normal carotid artery (CA) and (ii) Stenosed carotid artery (SCA). The Newtonian model has been used to study the physics of fluid. The findings of the two models are thoroughly compared in order to observe there behavioral sequence of flows. The numerical results were presented in terms of velocity, pressure, wall shear stress distributions and cross sectional velocities as well as the streamlines contour. Stenosis disturbs the normal pattern of blood flow through the artery as reduced area. At stenosis region velocity and peak Reynolds number rapidly increase and Reynolds number reach transitional and turbulent region. These flow fluctuation and turbulence have bad effect to the blood vessel which makes to accelerate the progress of stenosis.

  11. Blood Outgrowth Endothelial Cells Increase Tumor Growth Rates and Modify Tumor Physiology: Relevance for Therapeutic Targeting

    Energy Technology Data Exchange (ETDEWEB)

    Pagan, Jonathan, E-mail: jdpagan@uams.edu; Przybyla, Beata; Jamshidi-Parsian, Azemat [Department of Radiation Oncology, University of Arkansas for Medical Sciences, 4301 West Markham Street, Little Rock, AR 72205 (United States); Gupta, Kalpna [Vascular Biology Center and Division of Hematology-Oncology Transplantation, Department of Medicine, University of Minnesota Medical School, MN 72223 (United States); Griffin, Robert J. [Department of Radiation Oncology, University of Arkansas for Medical Sciences, 4301 West Markham Street, Little Rock, AR 72205 (United States)

    2013-02-18

    Endothelial cell precursors from human peripheral blood have been shown to home to areas of neovascularization and may assist tumor growth by increasing or fortifying blood vessel growth. In the present study, the influence of these cells on tumor growth and physiology was investigated and the role of these cells as a therapeutic target or in determining treatment sensitivity was tested. After isolation from human blood and expansion in vitro, actively growing cells with verified endothelial phenotype (Blood Outgrowth Endothelial Cell, BOEC) were injected i.v. into tumor bearing mice for three consecutive days. The growth rate was significantly enhanced in relatively small RERF human lung tumors (i.e., less than 150 mm{sup 3}) grown in immunocompromised mice by an average of 1.5-fold while it had no effect when injections were given to animals bearing larger tumors. There were no signs of toxicity or unwanted systemic effects. We also observed evidence of increased perfusion, vessel number, response to 15 Gy radiation and oxygenation in RERF tumors of animals injected with BOECs compared to control tumors. In addition, FSaII murine fibrosarcoma tumors were found to grow faster upon injection of BOECs. When FSaII tumors were subjected to a partial thermal ablation treatment using high intensity focused ultrasound (HIFU) there was consistently elevated detection of fluorescently labeled and i.v. injected endothelial precursors in the tumor when analyzed with optical imaging and/or histological preparations. Importantly, we also observed that BOECs treated with the novel anti-angiogenic peptide anginex in-vitro, show decreased proliferation and increased sensitivity to radiation. In vivo, the normal increase in FSaII tumor growth induced by injected BOECs was blunted by the addition of anginex treatment. It appears that endothelial precursors may significantly contribute to tumor vessel growth, tumor progression and/or repair of tumor damage and may improve the

  12. Blood Outgrowth Endothelial Cells Increase Tumor Growth Rates and Modify Tumor Physiology: Relevance for Therapeutic Targeting

    International Nuclear Information System (INIS)

    Pagan, Jonathan; Przybyla, Beata; Jamshidi-Parsian, Azemat; Gupta, Kalpna; Griffin, Robert J.

    2013-01-01

    Endothelial cell precursors from human peripheral blood have been shown to home to areas of neovascularization and may assist tumor growth by increasing or fortifying blood vessel growth. In the present study, the influence of these cells on tumor growth and physiology was investigated and the role of these cells as a therapeutic target or in determining treatment sensitivity was tested. After isolation from human blood and expansion in vitro, actively growing cells with verified endothelial phenotype (Blood Outgrowth Endothelial Cell, BOEC) were injected i.v. into tumor bearing mice for three consecutive days. The growth rate was significantly enhanced in relatively small RERF human lung tumors (i.e., less than 150 mm 3 ) grown in immunocompromised mice by an average of 1.5-fold while it had no effect when injections were given to animals bearing larger tumors. There were no signs of toxicity or unwanted systemic effects. We also observed evidence of increased perfusion, vessel number, response to 15 Gy radiation and oxygenation in RERF tumors of animals injected with BOECs compared to control tumors. In addition, FSaII murine fibrosarcoma tumors were found to grow faster upon injection of BOECs. When FSaII tumors were subjected to a partial thermal ablation treatment using high intensity focused ultrasound (HIFU) there was consistently elevated detection of fluorescently labeled and i.v. injected endothelial precursors in the tumor when analyzed with optical imaging and/or histological preparations. Importantly, we also observed that BOECs treated with the novel anti-angiogenic peptide anginex in-vitro, show decreased proliferation and increased sensitivity to radiation. In vivo, the normal increase in FSaII tumor growth induced by injected BOECs was blunted by the addition of anginex treatment. It appears that endothelial precursors may significantly contribute to tumor vessel growth, tumor progression and/or repair of tumor damage and may improve the

  13. Examination of uteroplacental blood flow with 113mIn (in physiological pregnancies)

    International Nuclear Information System (INIS)

    Ryznar, V.; Erban, J.; Pohanka, J.

    1986-01-01

    The total of 106 pregnant women in their 3rd trimester of physiological pregnancies were examined using 113m In and an LFOV Anger camera for the inflow rate of the applied radionuclide into the uteroplacental bed. The slope and T 1/2 were computed and the values valid for physiological pregnancies were defined. The authors' own method of normalization is used to process the obtained flow curves and all the data are assessed with the help of a PDP 11/34 on-line computer. In physiological pregnancies, T 1/2 and slope values for the 3rd trimester were found not to be influenced by the duration of the pregnancy or age of the pregnant woman. The discovered range of normal values for physiological pregnancies in their 3rd trimester are T 1/2 =8.3±1.7 s, slope more than 33. (author). 6 figs., 2 tabs., 34 refs

  14. Essays on the relevance and use of dirty surplus accounting flows in Europe

    NARCIS (Netherlands)

    Wang, Y.

    2006-01-01

    This thesis intends to add empirical evidence to a recently heavily debated regulatory issue, the necessity of promoting a clean surplus income statement. I document the magnitude, and assess the relevance of dirty surplus accounting flows in European member states. In particular, this thesis

  15. Physiological Signal Analysis for Evaluating Flow during Playing of Computer Games of Varying Difficulty

    Directory of Open Access Journals (Sweden)

    Yu Tian

    2017-07-01

    Full Text Available Flow is the experience of effortless attention, reduced self-consciousness, and a deep sense of control that typically occurs during the optimal performance of challenging tasks. On the basis of the person–artifact–task model, we selected computer games (tasks with varying levels of difficulty (difficult, medium, and easy and shyness (personality as flow precursors to study the physiological activity of users in a flow state. Cardiac and respiratory activity and mean changes in skin conductance (SC were measured continuously while the participants (n = 40 played the games. Moreover, the associations between self-reported psychological flow and physiological measures were investigated through a series of repeated-measures analyses. The results showed that the flow experience is related to a faster respiratory rate, deeper respiration, moderate heart rate (HR, moderate HR variability, and moderate SC. The main effect of shyness was non-significant, whereas the interaction of shyness and difficulty influenced the flow experience. These findings are discussed in relation to current models of arousal and valence. The results indicate that the flow state is a state of moderate mental effort that arises through the increased parasympathetic modulation of sympathetic activity.

  16. Physiological Signal Analysis for Evaluating Flow during Playing of Computer Games of Varying Difficulty.

    Science.gov (United States)

    Tian, Yu; Bian, Yulong; Han, Piguo; Wang, Peng; Gao, Fengqiang; Chen, Yingmin

    2017-01-01

    Flow is the experience of effortless attention, reduced self-consciousness, and a deep sense of control that typically occurs during the optimal performance of challenging tasks. On the basis of the person-artifact-task model, we selected computer games (tasks) with varying levels of difficulty (difficult, medium, and easy) and shyness (personality) as flow precursors to study the physiological activity of users in a flow state. Cardiac and respiratory activity and mean changes in skin conductance (SC) were measured continuously while the participants ( n = 40) played the games. Moreover, the associations between self-reported psychological flow and physiological measures were investigated through a series of repeated-measures analyses. The results showed that the flow experience is related to a faster respiratory rate, deeper respiration, moderate heart rate (HR), moderate HR variability, and moderate SC. The main effect of shyness was non-significant, whereas the interaction of shyness and difficulty influenced the flow experience. These findings are discussed in relation to current models of arousal and valence. The results indicate that the flow state is a state of moderate mental effort that arises through the increased parasympathetic modulation of sympathetic activity.

  17. In vivo analysis of physiological 3D blood flow of cerebral veins

    Energy Technology Data Exchange (ETDEWEB)

    Schuchardt, Florian; Schroeder, Laure; Baeuerle, Jochen; Harloff, Andreas [University Medical Centre, Department of Neurology, Freiburg (Germany); Anastasopoulos, Constantin [University Medical Center, Department of Neuropaediatrics and Muscle Disorders, Freiburg (Germany); University Medical Centre, Department of Neuroradiology, Freiburg (Germany); Markl, Michael [Northwestern University, Department of Radiology, Feinberg School of Medicine and McCormick School of Engineering, Chicago, IL (United States); Hennemuth, Anja; Drexl, Johann [Fraunhofer MEVIS, Bremen (Germany); Valdueza, Jose M. [Neurological Center, Segeberger Kliniken, Bad Segeberg (Germany); Mader, Irina [University Medical Centre, Department of Neuroradiology, Freiburg (Germany)

    2015-08-15

    To visualize and quantify physiological blood flow of intracranial veins in vivo using time-resolved, 3D phase-contrast MRI (4D flow MRI), and to test measurement accuracy. Fifteen healthy volunteers underwent repeated ECG-triggered 4D flow MRI (3 Tesla, 32-channel head coil). Intracranial venous blood flow was analysed using dedicated software allowing for blood flow visualization and quantification in analysis planes at the superior sagittal, straight, and transverse sinuses. MRI was evaluated for intra- and inter-observer agreement and scan-rescan reproducibility. Measurements of the transverse sinuses were compared with transcranial two-dimensional duplex ultrasound. Visualization of 3D blood flow within cerebral sinuses was feasible in 100 % and within at least one deep cerebral vein in 87 % of the volunteers. Blood flow velocity/volume increased along the superior sagittal sinus and was lower in the left compared to the right transverse sinus. Intra- and inter-observer reliability and reproducibility of blood flow velocity (mean difference 0.01/0.02/0.02 m/s) and volume (mean difference 0.0002/-0.0003/0.00003 l/s) were good to excellent. High/low velocities were more pronounced (8 % overestimation/9 % underestimation) in MRI compared to ultrasound. Four-dimensional flow MRI reliably visualizes and quantifies three-dimensional cerebral venous blood flow in vivo and is promising for studies in patients with sinus thrombosis and related diseases. (orig.)

  18. Pollen Contaminated With Field-Relevant Levels of Cyhalothrin Affects Honey Bee Survival, Nutritional Physiology, and Pollen Consumption Behavior.

    Science.gov (United States)

    Dolezal, Adam G; Carrillo-Tripp, Jimena; Miller, W Allen; Bonning, Bryony C; Toth, Amy L

    2016-02-01

    Honey bees are exposed to a variety of environmental factors that impact their health, including nutritional stress, pathogens, and pesticides. In particular, there has been increasing evidence that sublethal exposure to pesticides can cause subtle, yet important effects on honey bee health and behavior. Here, we add to this body of knowledge by presenting data on bee-collected pollen containing sublethal levels of cyhalothrin, a pyrethroid insecticide, which, when fed to young honey bees, resulted in significant changes in lifespan, nutritional physiology,and behavior. For the first time, we show that when young, nest-aged bees are presented with pollen containing field-relevant levels of cyhalothrin, they reduce their consumption of contaminated pollen. This indicates that, at least for some chemicals, young bees are able to detect contamination in pollen and change their behavioral response, even if the contamination levels do not prevent foraging honey bees from collecting the contaminated pollen.

  19. Imaging-Based Screen Identifies Laminin 411 as a Physiologically Relevant Niche Factor with Importance for i-Hep Applications

    Directory of Open Access Journals (Sweden)

    John Ong

    2018-03-01

    Full Text Available Summary: Use of hepatocytes derived from induced pluripotent stem cells (i-Heps is limited by their functional differences in comparison with primary cells. Extracellular niche factors likely play a critical role in bridging this gap. Using image-based characterization (high content analysis; HCA of freshly isolated hepatocytes from 17 human donors, we devised and validated an algorithm (Hepatocyte Likeness Index; HLI for comparing the hepatic properties of cells against a physiological gold standard. The HLI was then applied in a targeted screen of extracellular niche factors to identify substrates driving i-Heps closer to the standard. Laminin 411, the top hit, was validated in two additional induced pluripotent stem cell (iPSC lines, primary tissue, and an in vitro model of α1-antitrypsin deficiency. Cumulatively, these data provide a reference method to control and screen for i-Hep differentiation, identify Laminin 411 as a key niche protein, and underscore the importance of combining substrates, soluble factors, and HCA when developing iPSC applications. : Rashid and colleagues demonstrate the utility of a high-throughput imaging platform for identification of physiologically relevant extracellular niche factors to advance i-Heps closer to their primary tissue counterparts. The extracellular matrix (ECM protein screen identified Laminin 411 as an important niche factor facilitating i-Hep-based disease modeling in vitro. Keywords: iPS hepatocytes, extracellular niche, image-based screening, disease modeling, laminin

  20. On making nursing undergraduate human reproductive physiology content meaningful and relevant: discussion of human pleasure in its biological context.

    Science.gov (United States)

    McClusky, Leon Mendel

    2012-01-01

    The traditional presentation of the Reproductive Physiology component in an Anatomy and Physiology course to nursing undergraduates focuses on the broad aspects of hormonal regulation of reproduction and gonadal anatomy, with the role of the higher centres of the brain omitted. An introductory discussion is proposed which could precede the lectures on the reproductive organs. The discussion gives an overview of the biological significance of human pleasure, the involvement of the neurotransmitter dopamine, and the role of pleasure in the survival of the individual and even species. Pleasure stimuli (positive and negative) and the biological significance of naturally-induced pleasurable experiences are briefly discussed in the context of reproduction and the preservation of genetic material with an aim to foster relevancy between subject material and human behaviour in any type of society. The tenderness of this aspect of the human existence is well-understood because of its invariable association with soul-revealing human expressions such as love, infatuation, sexual flirtations, all of which are underpinned by arousal, desire and/or pleasure. Assuming that increased knowledge correlates with increased confidence, the proposed approach may provide the nurse with an adequate knowledge base to overcome well-known barriers in communicating with their patients about matters of sexual health and intimacy. Copyright © 2011 Elsevier Ltd. All rights reserved.

  1. Single-molecule analysis reveals the kinetics and physiological relevance of MutL-ssDNA binding.

    Directory of Open Access Journals (Sweden)

    Jonghyun Park

    2010-11-01

    Full Text Available DNA binding by MutL homologs (MLH/PMS during mismatch repair (MMR has been considered based on biochemical and genetic studies. Bulk studies with MutL and its yeast homologs Mlh1-Pms1 have suggested an integral role for a single-stranded DNA (ssDNA binding activity during MMR. We have developed single-molecule Förster resonance energy transfer (smFRET and a single-molecule DNA flow-extension assays to examine MutL interaction with ssDNA in real time. The smFRET assay allowed us to observe MutL-ssDNA association and dissociation. We determined that MutL-ssDNA binding required ATP and was the greatest at ionic strength below 25 mM (K(D = 29 nM while it dramatically decreases above 100 mM (K(D>2 µM. Single-molecule DNA flow-extension analysis suggests that multiple MutL proteins may bind ssDNA at low ionic strength but this activity does not enhance stability at elevated ionic strengths. These studies are consistent with the conclusion that a stable MutL-ssDNA interaction is unlikely to occur at physiological salt eliminating a number of MMR models. However, the activity may infer some related dynamic DNA transaction process during MMR.

  2. Clinically Relevant Levels of 4-Aminopyridine Strengthen Physiological Responses in Intact Motor Circuits in Rats, Especially After Pyramidal Tract Injury.

    Science.gov (United States)

    Sindhurakar, Anil; Mishra, Asht M; Gupta, Disha; Iaci, Jennifer F; Parry, Tom J; Carmel, Jason B

    2017-04-01

    4-Aminopyridine (4-AP) is a Food and Drug Administration-approved drug to improve motor function in people with multiple sclerosis. Preliminary results suggest the drug may act on intact neural circuits and not just on demyelinated ones. To determine if 4-AP at clinically relevant levels alters the excitability of intact motor circuits. In anesthetized rats, electrodes were placed over motor cortex and the dorsal cervical spinal cord for electrical stimulation, and electromyogram electrodes were inserted into biceps muscle to measure responses. The motor responses to brain and spinal cord stimulation were measured before and for 5 hours after 4-AP administration both in uninjured rats and rats with a cut lesion of the pyramidal tract. Blood was collected at the same time as electrophysiology to determine drug plasma concentration with a goal of 20 to 100 ng/mL. We first determined that a bolus infusion of 0.32 mg/kg 4-AP was optimal: it produced on average 61.5 ± 1.8 ng/mL over the 5 hours after infusion. This dose of 4-AP increased responses to spinal cord stimulation by 1.3-fold in uninjured rats and 3-fold in rats with pyramidal tract lesion. Responses to cortical stimulation also increased by 2-fold in uninjured rats and up to 4-fold in the injured. Clinically relevant levels of 4-AP strongly augment physiological responses in intact circuits, an effect that was more robust after partial injury, demonstrating its broad potential in treating central nervous system injuries.

  3. Physiologically-Relevant Modes of Membrane Interactions by the Human Antimicrobial Peptide, LL-37, Revealed by SFG Experiments

    Science.gov (United States)

    Ding, Bei; Soblosky, Lauren; Nguyen, Khoi; Geng, Junqing; Yu, Xinglong; Ramamoorthy, Ayyalusamy; Chen, Zhan

    2013-05-01

    Antimicrobial peptides (AMPs) could become the next generation antibiotic compounds which can overcome bacterial resistance by disrupting cell membranes and it is essential to determine the factors underlying its mechanism of action. Although high-resolution NMR and other biological studies have provided valuable insights, it has been a major challenge to follow the AMP-membrane interactions at physiologically-relevant low peptide concentrations. In this study, we demonstrate a novel approach to overcome this major limitation by performing Sum Frequency Generation (SFG) vibrational spectroscopic experiments on lipid bilayers containing an AMP, LL-37. Our results demonstrate the power of SFG to study non-linear helical peptides and also infer that lipid-peptide interaction and the peptide orientation depend on the lipid membrane composition. The observed SFG signal changes capture the aggregating process of LL-37 on membrane. In addition, our SFG results on cholesterol-containing lipid bilayers indicate the inhibition effect of cholesterol on peptide-induced membrane permeation process.

  4. Regulation of increased blood flow (hyperemia) to muscles during exercise: a hierarchy of competing physiological needs.

    Science.gov (United States)

    Joyner, Michael J; Casey, Darren P

    2015-04-01

    This review focuses on how blood flow to contracting skeletal muscles is regulated during exercise in humans. The idea is that blood flow to the contracting muscles links oxygen in the atmosphere with the contracting muscles where it is consumed. In this context, we take a top down approach and review the basics of oxygen consumption at rest and during exercise in humans, how these values change with training, and the systemic hemodynamic adaptations that support them. We highlight the very high muscle blood flow responses to exercise discovered in the 1980s. We also discuss the vasodilating factors in the contracting muscles responsible for these very high flows. Finally, the competition between demand for blood flow by contracting muscles and maximum systemic cardiac output is discussed as a potential challenge to blood pressure regulation during heavy large muscle mass or whole body exercise in humans. At this time, no one dominant dilator mechanism accounts for exercise hyperemia. Additionally, complex interactions between the sympathetic nervous system and the microcirculation facilitate high levels of systemic oxygen extraction and permit just enough sympathetic control of blood flow to contracting muscles to regulate blood pressure during large muscle mass exercise in humans. Copyright © 2015 the American Physiological Society.

  5. Physiologic assessment of coronary artery disease: Focus on fractional flow reserve

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Do Yeon; Koo, Bon Kwon [Dept. of Radiology, Internal Medicine and Cardiovascular Center, Seoul National University Hospital, Seoul (Korea, Republic of); Lee, Joo Myung [Dept. of Internal Medicine and Cardiovascular Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2016-06-15

    The presence of myocardial ischemia is the most important prognostic factor in patients with ischemic heart disease. Fractional flow reserve (FFR) is a gold standard invasive method used to detect the stenosis-specific myocardial ischemia. FFR-guided revascularization strategy is superior to angiography-guided strategy. The recently developed hyperemia-free index, instantaneous wave free ratio is being actively investigated. A non-invasive FFR derived from coronary CT angiography is now used in clinical practice. Due to rapid expansion of invasive and non-invasive physiologic assessment, comprehensive understanding of the role and potential pitfalls of each modality are required for its application. In this review, we focus on the basic and clinical aspects of physiologic assessment in ischemic heart disease.

  6. Physiologic assessment of coronary artery disease: Focus on fractional flow reserve

    International Nuclear Information System (INIS)

    Hwang, Do Yeon; Koo, Bon Kwon; Lee, Joo Myung

    2016-01-01

    The presence of myocardial ischemia is the most important prognostic factor in patients with ischemic heart disease. Fractional flow reserve (FFR) is a gold standard invasive method used to detect the stenosis-specific myocardial ischemia. FFR-guided revascularization strategy is superior to angiography-guided strategy. The recently developed hyperemia-free index, instantaneous wave free ratio is being actively investigated. A non-invasive FFR derived from coronary CT angiography is now used in clinical practice. Due to rapid expansion of invasive and non-invasive physiologic assessment, comprehensive understanding of the role and potential pitfalls of each modality are required for its application. In this review, we focus on the basic and clinical aspects of physiologic assessment in ischemic heart disease

  7. A D-Shaped Bileaflet Bioprosthesis which Replicates Physiological Left Ventricular Flow Patterns.

    Directory of Open Access Journals (Sweden)

    Sean Guo-Dong Tan

    Full Text Available Prior studies have shown that in a healthy heart, there exist a large asymmetric vortex structure that aids in establishing a steady flow field in the left ventricle. However, the implantation of existing artificial heart valves at the mitral position is found to have a negative effect on this physiological flow pattern. In light of this, a novel D-shaped bileaflet porcine bioprosthesis (GD valve has been designed based on the native geometry mitral valve, with the hypothesis that biomimicry in valve design can restore physiological left ventricle flow patterns after valve implantation. An in-vitro experiment using two dimensional particle velocimetry imaging was carried out to determine the hemodynamic performance of the new bileaflet design and then compared to that of the well-established St. Jude Epic valve which functioned as a control in the experiment. Although both valves were found to have similar Reynolds shear stress and Turbulent Kinetic Energy levels, the novel D-shape valve was found to have lower turbulence intensity and greater mean kinetic energy conservation.

  8. A D-Shaped Bileaflet Bioprosthesis which Replicates Physiological Left Ventricular Flow Patterns

    Science.gov (United States)

    Tan, Sean Guo-Dong; Kim, Sangho; Hon, Jimmy Kim Fatt; Leo, Hwa Liang

    2016-01-01

    Prior studies have shown that in a healthy heart, there exist a large asymmetric vortex structure that aids in establishing a steady flow field in the left ventricle. However, the implantation of existing artificial heart valves at the mitral position is found to have a negative effect on this physiological flow pattern. In light of this, a novel D-shaped bileaflet porcine bioprosthesis (GD valve) has been designed based on the native geometry mitral valve, with the hypothesis that biomimicry in valve design can restore physiological left ventricle flow patterns after valve implantation. An in-vitro experiment using two dimensional particle velocimetry imaging was carried out to determine the hemodynamic performance of the new bileaflet design and then compared to that of the well-established St. Jude Epic valve which functioned as a control in the experiment. Although both valves were found to have similar Reynolds shear stress and Turbulent Kinetic Energy levels, the novel D-shape valve was found to have lower turbulence intensity and greater mean kinetic energy conservation. PMID:27258099

  9. Form and function in hillslope hydrology: in situ imaging and characterization of flow-relevant structures

    Directory of Open Access Journals (Sweden)

    C. Jackisch

    2017-07-01

    Full Text Available The study deals with the identification and characterization of rapid subsurface flow structures through pedo- and geo-physical measurements and irrigation experiments at the point, plot and hillslope scale. Our investigation of flow-relevant structures and hydrological responses refers to the general interplay of form and function, respectively. To obtain a holistic picture of the subsurface, a large set of different laboratory, exploratory and experimental methods was used at the different scales. For exploration these methods included drilled soil core profiles, in situ measurements of infiltration capacity and saturated hydraulic conductivity, and laboratory analyses of soil water retention and saturated hydraulic conductivity. The irrigation experiments at the plot scale were monitored through a combination of dye tracer, salt tracer, soil moisture dynamics, and 3-D time-lapse ground penetrating radar (GPR methods. At the hillslope scale the subsurface was explored by a 3-D GPR survey. A natural storm event and an irrigation experiment were monitored by a dense network of soil moisture observations and a cascade of 2-D time-lapse GPR trenches. We show that the shift between activated and non-activated state of the flow paths is needed to distinguish structures from overall heterogeneity. Pedo-physical analyses of point-scale samples are the basis for sub-scale structure inference. At the plot and hillslope scale 3-D and 2-D time-lapse GPR applications are successfully employed as non-invasive means to image subsurface response patterns and to identify flow-relevant paths. Tracer recovery and soil water responses from irrigation experiments deliver a consistent estimate of response velocities. The combined observation of form and function under active conditions provides the means to localize and characterize the structures (this study and the hydrological processes (companion study Angermann et al., 2017, this issue.

  10. Form and function in hillslope hydrology: in situ imaging and characterization of flow-relevant structures

    Science.gov (United States)

    Jackisch, Conrad; Angermann, Lisa; Allroggen, Niklas; Sprenger, Matthias; Blume, Theresa; Tronicke, Jens; Zehe, Erwin

    2017-07-01

    The study deals with the identification and characterization of rapid subsurface flow structures through pedo- and geo-physical measurements and irrigation experiments at the point, plot and hillslope scale. Our investigation of flow-relevant structures and hydrological responses refers to the general interplay of form and function, respectively. To obtain a holistic picture of the subsurface, a large set of different laboratory, exploratory and experimental methods was used at the different scales. For exploration these methods included drilled soil core profiles, in situ measurements of infiltration capacity and saturated hydraulic conductivity, and laboratory analyses of soil water retention and saturated hydraulic conductivity. The irrigation experiments at the plot scale were monitored through a combination of dye tracer, salt tracer, soil moisture dynamics, and 3-D time-lapse ground penetrating radar (GPR) methods. At the hillslope scale the subsurface was explored by a 3-D GPR survey. A natural storm event and an irrigation experiment were monitored by a dense network of soil moisture observations and a cascade of 2-D time-lapse GPR trenches. We show that the shift between activated and non-activated state of the flow paths is needed to distinguish structures from overall heterogeneity. Pedo-physical analyses of point-scale samples are the basis for sub-scale structure inference. At the plot and hillslope scale 3-D and 2-D time-lapse GPR applications are successfully employed as non-invasive means to image subsurface response patterns and to identify flow-relevant paths. Tracer recovery and soil water responses from irrigation experiments deliver a consistent estimate of response velocities. The combined observation of form and function under active conditions provides the means to localize and characterize the structures (this study) and the hydrological processes (companion study Angermann et al., 2017, this issue).

  11. A global database of sap flow measurements (SAPFLUXNET) to link plant and ecosystem physiology

    Science.gov (United States)

    Poyatos, Rafael; Granda, Víctor; Flo, Víctor; Molowny-Horas, Roberto; Mencuccini, Maurizio; Oren, Ram; Katul, Gabriel; Mahecha, Miguel; Steppe, Kathy; Martínez-Vilalta, Jordi

    2017-04-01

    Regional and global networks of ecosystem CO2 and water flux monitoring have dramatically increased our understanding of ecosystem functioning in the last 20 years. More recently, analyses of ecosystem-level fluxes have successfully incorporated data streams at coarser (remote sensing) and finer (plant traits) organisational scales. However, there are few data sources that capture the diel to seasonal dynamics of whole-plant physiology and that can provide a link between organism- and ecosystem-level function. Sap flow measured in plant stems reveals the temporal patterns in plant water transport, as mediated by stomatal regulation and hydraulic architecture. The widespread use of thermometric methods of sap flow measurement since the 1990s has resulted in numerous data sets for hundreds of species and sites worldwide, but these data have remained fragmentary and generally unavailable for syntheses of regional to global scope. We are compiling the first global database of sub-daily sap flow measurements in individual plants (SAPFLUXNET), aimed at unravelling the environmental and biotic drivers of plant transpiration regulation globally. I will present the SAPFLUXNET data infrastructure and workflow, which is built upon flexible, open-source computing tools within the R environment (dedicated R packages and classes, interactive documents and apps with Rmarkdown and Shiny). Data collection started in mid-2016, we have already incorporated > 50 datasets representing > 40 species and > 350 individual plants, globally distributed, and the number of contributed data sets is increasing rapidly. I will provide a general overview of the distribution of available data sets according to climate, measurement method, species, functional groups and plant size attributes. In parallel to the sap flow data compilation, we have also collated published results from calibrations of sap flow methods, to provide a first quantification on the variability associated with different sap

  12. On-line coupling of physiologically relevant bioaccessibility testing to inductively coupled plasma spectrometry: Proof of concept for fast assessment of gastrointestinal bioaccessibility of micronutrients from soybeans.

    Science.gov (United States)

    Herrera, Mónica Alejandra; Rosende, María; Arruda, Marco Aurélio Zezzi; Miró, Manuel

    2016-10-05

    In-vitro physiologically relevant gastrointestinal extraction based on the validated Unified BARGE Method (UBM) is in this work hyphenated to inductively coupled plasma optical emission spectrometry in a batch-flow configuration for real-time monitoring of oral bioaccessibility assays with high temporal resolution. A fully automated flow analyzer is designed to foster in-line filtration of gastrointestinal extracts at predefined times (≤15 min) followed by on-line multi-elemental analysis of bioaccessible micro-nutrients, viz., Cu, Fe and Mn, in well-defined volumes of extracts (300 μL) of transgenic and non-transgenic soybean seeds taken as model samples. The hyphenated flow setup allows for recording of temporal extraction profiles to gain full knowledge of the kinetics of the gastrointestinal digestion processes, including element leaching and concomitant precipitation and complexation reactions hindering bioavailability. Simplification of the overall standard procedure is also feasible by identification of steady-state extraction conditions. Our findings indicate that reliable measurement of oral bioaccessible pools of Cu, Fe and Mn in soybean might be obtained in less than 180 min rather than 240 min as endorsed by UBM. Using a matrix-matched external calibration, limits of detection according to the 3s criteria were 0.5 μg/g for Mn, 0.6 μg/g for Cu and 2.3 μg/g for Fe. Trueness of the automatic bioaccessibility method was confirmed by mass balance validation with recoveries ranging from 87 to 116% regardless of the target element and sample. Cu was the micronutrient with the highest oral bioaccessibility ranging from 73% to 83% (7.5-7.9 μg/g) for non-transgenic and transgenic soybeans, respectively, followed by Mn and Fe within the ranges of 29-31% (10.8-11.4 μg/g) and 11-15% (8-14 μg/g), respectively, regardless of transgenesis. The proposed kinetic method is proven suitable for fast and expedient estimation of the nutritional value of

  13. Applications of flow cytometry in plant pathology for genome size determination, detection and physiological status.

    Science.gov (United States)

    D'Hondt, Liesbet; Höfte, Monica; Van Bockstaele, Erik; Leus, Leen

    2011-10-01

    Flow cytometers are probably the most multipurpose laboratory devices available. They can analyse a vast and very diverse range of cell parameters. This technique has left its mark on cancer, human immunodeficiency virus and immunology research, and is indispensable in routine clinical diagnostics. Flow cytometry (FCM) is also a well-known tool for the detection and physiological status assessment of microorganisms in drinking water, marine environments, food and fermentation processes. However, flow cytometers are seldom used in plant pathology, despite FCM's major advantages as both a detection method and a research tool. Potential uses of FCM include the characterization of genome sizes of fungal and oomycete populations, multiplexed pathogen detection and the monitoring of the viability, culturability and gene expression of plant pathogens, and many others. This review provides an overview of the history, advantages and disadvantages of FCM, and focuses on the current applications and future possibilities of FCM in plant pathology. © 2011 THE AUTHORS. MOLECULAR PLANT PATHOLOGY © 2011 BSPP AND BLACKWELL PUBLISHING LTD.

  14. A novel role of thrombopoietin as a physiological modulator of coronary flow.

    Science.gov (United States)

    Ramella, Roberta; Gallo, Maria Pia; Spatola, Tiziana; Lupia, Enrico; Alloatti, Giuseppe

    2011-02-25

    Thrombopoietin (TPO) is known for its ability to stimulate platelet production. However, little is currently known whether TPO plays a physiological function in the heart. The potential vasodilatory role of TPO was tested on the isolated rat heart. The expression of TPO receptor (c-mpl) and the TPO-dependent eNOS phosphorylation (P(Ser1179)) were studied on Cardiac-derived normal Human Micro Vascular Endothelial Cells (HMVEC-C) by Western blot analysis. While TPO (10-200 pg/mL) did not modify coronary flow (CF) under basal conditions, it reduced the coronary constriction caused by endothelin-1 (ET-1; 10nM) in a dose-dependent manner. This effect was blocked by both Wortmannin (100 nM) and L-NAME (100 nM); on HMVEC-C, TPO induced eNOS phosphorylation through a Wortmannin sensitive mechanism. Taken together, our data suggest a potential role of TPO as a physiological regulator of CF. By acting on specific receptors present on endothelial cells, TPO may induce PI3K/Akt-dependent eNOS phosphorylation and NO release. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. A G Protein-biased Designer G Protein-coupled Receptor Useful for Studying the Physiological Relevance of Gq/11-dependent Signaling Pathways.

    Science.gov (United States)

    Hu, Jianxin; Stern, Matthew; Gimenez, Luis E; Wanka, Lizzy; Zhu, Lu; Rossi, Mario; Meister, Jaroslawna; Inoue, Asuka; Beck-Sickinger, Annette G; Gurevich, Vsevolod V; Wess, Jürgen

    2016-04-08

    Designerreceptorsexclusivelyactivated by adesignerdrug (DREADDs) are clozapine-N-oxide-sensitive designer G protein-coupled receptors (GPCRs) that have emerged as powerful novel chemogenetic tools to study the physiological relevance of GPCR signaling pathways in specific cell types or tissues. Like endogenous GPCRs, clozapine-N-oxide-activated DREADDs do not only activate heterotrimeric G proteins but can also trigger β-arrestin-dependent (G protein-independent) signaling. To dissect the relative physiological relevance of G protein-mediatedversusβ-arrestin-mediated signaling in different cell types or physiological processes, the availability of G protein- and β-arrestin-biased DREADDs would be highly desirable. In this study, we report the development of a mutationally modified version of a non-biased DREADD derived from the M3muscarinic receptor that can activate Gq/11with high efficacy but lacks the ability to interact with β-arrestins. We also demonstrate that this novel DREADD is activein vivoand that cell type-selective expression of this new designer receptor can provide novel insights into the physiological roles of G protein (Gq/11)-dependentversusβ-arrestin-dependent signaling in hepatocytes. Thus, this novel Gq/11-biased DREADD represents a powerful new tool to study the physiological relevance of Gq/11-dependent signaling in distinct tissues and cell types, in the absence of β-arrestin-mediated cellular effects. Such studies should guide the development of novel classes of functionally biased ligands that show high efficacy in various pathophysiological conditions but display a reduced incidence of side effects. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  16. Focal physiological uncoupling of cerebral blood flow and oxidative metabolism during somatosensory stimulation in human subjects

    International Nuclear Information System (INIS)

    Fox, P.T.; Raichle, M.E.

    1986-01-01

    Coupling between cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO 2 ) was studied using multiple sequential administrations of 15 O-labeled radiotracers and positron emission tomography. In the resting state an excellent correlation between CBF and CMRO 2 was found when paired measurements of CBF and CMRO 2 from multiple (30-48) brain regions were tested in each of 33 normal subjects. Regional uncoupling of CBF and CMRO 2 was found, however, during neuronal activation induced by somatosensory stimulation. Stimulus-induced focal augmentation of cerebral blood flow (29% mean) far exceeded the concomitant local increase in tissue metabolic rate (mean, 5%), when resting-state and stimulated-state measurements were obtained in each of 9 subjects. Stimulus duration had no significant effect on response magnitude or on the degree of CBF-CMRO 2 uncoupling observed. Dynamic, physiological regulation of CBF by a mechanism (neuronal or biochemical) dependent on neuronal firing per se, but independent of the cerebral metabolic rate of oxygen, is hypothesized

  17. Eppur Si Muove: The dynamic nature of physiological control of renal blood flow by the renal sympathetic nerves.

    Science.gov (United States)

    Schiller, Alicia M; Pellegrino, Peter Ricci; Zucker, Irving H

    2017-05-01

    Tubuloglomerular feedback and the myogenic response are widely appreciated as important regulators of renal blood flow, but the role of the sympathetic nervous system in physiological renal blood flow control remains controversial. Where classic studies using static measures of renal blood flow failed, dynamic approaches have succeeded in demonstrating sympathetic control of renal blood flow under normal physiological conditions. This review focuses on transfer function analysis of renal pressure-flow, which leverages the physical relationship between blood pressure and flow to assess the underlying vascular control mechanisms. Studies using this approach indicate that the renal nerves are important in the rapid regulation of the renal vasculature. Animals with intact renal innervation show a sympathetic signature in the frequency range associated with sympathetic vasomotion that is eliminated by renal denervation. In conscious rabbits, this sympathetic signature exerts vasoconstrictive, baroreflex control of renal vascular conductance, matching well with the rhythmic, baroreflex-influenced control of renal sympathetic nerve activity and complementing findings from other studies employing dynamic approaches to study renal sympathetic vascular control. In this light, classic studies reporting that nerve stimulation and renal denervation do not affect static measures of renal blood flow provide evidence for the strength of renal autoregulation rather than evidence against physiological renal sympathetic control of renal blood flow. Thus, alongside tubuloglomerular feedback and the myogenic response, renal sympathetic outflow should be considered an important physiological regulator of renal blood flow. Clinically, renal sympathetic vasomotion may be important for solving the problems facing the field of therapeutic renal denervation. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Resting Pd/Pa and haemodynamic relevance of coronary stenosis as evaluated by fractional flow reserve.

    Science.gov (United States)

    De Luca, Giuseppe; Verdoia, Monica; Barbieri, Lucia; Marino, Paolo; Suryapranata, Harry

    2018-03-01

    Fractional flow reserve (FFR) currently represents the gold standard in the evaluation of the haemodynamic relevance of coronary stenoses. However, both intracoronary and intravenous adenosine may be tolerated poorly by some patients. Therefore, considerable interest had been focused in the last few years on new adenosine-free indexes to define the haemodynamic relevance of coronary stenoses. So far, few data have been reported on resting Pd/Pa and its correlation with FFR as evaluated with high-dose intracoronary adenosine administration, which is the aim of the current study. FFR was assessed in 120 patients with 137 intermediate lesions during cardiac catheterization by a pressure-recording guidewire (PrimeWire). FFR was calculated as the ratio of the distal coronary pressure to the aortic pressure at hyperaemia. Intracoronary doses of adenosine were administered up to 720 μg as intracoronary boli. Exclusion criteria were as follows: (a) allergy to adenosine; (b) baseline bradycardia (heart rate values and increased the percentage of patients showing an FFR less than 0.80. Resting Pd/Pa showed good accuracy in the identification of patients with significant FFR values (value in the prediction of a positive FFR value. A value up to 0.88 was associated with a 100% positive predictive value, whereas a value of at least 0.95 was associated with a 95% negative predictive value. This study showed that in intermediate lesions, resting Pd/Pa was related linearly to FFR. We identified 0.93 as the best cut-off value in the prediction of haemodynamically significant coronary stenosis as evaluated by FFR. However, cut-off values of 0.88 and 0.95 could provide the maximal predictive positive and negative values, suggesting the additional use of FFR only in patients with resting values within this range.

  19. MANA YANG LEBIH MEMILIKI VALUE-RELEVANT: NET INCOME ATAU CASH FLOWS (Studi Terhadap Siklus Hidup Organisasi

    Directory of Open Access Journals (Sweden)

    Juniarti Juniarti

    2005-01-01

    Full Text Available This research is aimed to examine the relative value-relevant of net income and cash flow measures in different life cycle stages. Corporate life cycle consists of four stages: start up, growth, mature, and decline stage. Firms in different life cycle stages have different characteristics, and therefore in each life cycle stages the usefulness of accounting measures also different. Net incomes are predicted to be more value relevant in mature stages, while cash flows are expected to be more value relevant in stages characterized by start up, growth, and decline stages. The results prove that in the growth stage, the analysis supports the hypothesis that cash flows are more value relevant than net income. However, in the mature stage, the analysis results reject the hypothesis. This research do not analyze for the start up stage and decline stage, because of the limitation of the sample data. Abstract in Bahasa Indonesia: Penelitian ini bertujuan untuk menguji manakah yang lebih memiliki value-relevant pengukuran laba atau arus kas pada masing-masing siklus hidup perusahaan. Siklus hidup perusahaan umumnya terbagi dalam tahap start-up, growth, mature dan decline. Karakteristik perusahaan berbeda untuk setiap tahap siklus hidup tersebut, karena itu kegunaan pengukuran akuntansi juga akan berbeda. Laba diperkirakan lebih memiliki value-relevant pada tahap mature, sementara arus kas diekspektasikan lebih memiliki value-relevant ketika perusahaan berada pada tahap start-up, growth dan decline. Penelitian ini membuktikan bahwa pada tahap growth, hasil pengujian yang dilakukan mendukung hipotesis bahwa cash flow lebih memiliki value relevant dibanding laba. Tetapi, untuk tahap mature, hipotesis yang diajukan tidak berhasil dibuktikan. Penelitian ini tidak dapat melakukan pengujian untuk tahap start-up dan decline, dikarenakan data sampel untuk kedua tahap tersebut tidak mencukupi untuk dilakukan pengujian. Kata kunci: siklus hidup organisasi, value-relevant

  20. Heat transfer and fluid flow research relevant to India's nuclear power program

    International Nuclear Information System (INIS)

    Mehta, S.K.; Venkatraj, V.

    1988-01-01

    The Indian Nuclear Power Programme envisages three important stages viz., installation of thermal reactors, fast reactors and utilization of Thorium. By the year 2000 AD, it is proposed to have an installed total capacity of nuclear power of about 10,000 MWe. Starting from the present installed capacity of 1330 MWe, the additional contribution will be mainly made by thermal power reactors of the Pressurized Heavy Water type (PHWR). Apart from the reactors presently under construction about 12 numbers of 235 MWe units are planned to be constructed, which will be based on the standardized design of the reactors at Narora Atomic Power Project (NAPP). In addition, 10 units of 500 MWe capacity each, the design for which is currently under progress, will also be installed. The design, construction and operating agency is the Nuclear Power Board (NPB), while the Bhabha Atomic Research Centre (BARC) is responsible for the research and development work required. In addition to the programme on thermal power reactors, a thermal research reactor (DHRUVA) of 100 MWth capacity has been designed, constructed and has been commissioned. Some of the important heat transfer and fluid flow research problems relevant to the Indian nuclear power and research reactors are discussed in this paper

  1. Cerebral blood flow and intracranial pulsatility studied with MRI: measurement, physiological and pathophysiological aspects

    Energy Technology Data Exchange (ETDEWEB)

    Waahlin, Anders

    2012-07-01

    During each cardiac cycle pulsatile arterial blood inflates the vascular bed of the brain, forcing cerebrospinal fluid (CSF) and venous blood out of the cranium. Excessive arterial pulsatility may be part of a harmful mechanism causing cognitive decline among elderly. Additionally, restricted venous flow from the brain is suggested as the cause of multiple sclerosis. Addressing hypotheses derived from these observations requires accurate and reliable investigational methods. This work focused on assessing the pulsatile waveform of cerebral arterial, venous and CSF flows. The overall aim of this dissertation was to explore cerebral blood flow and intracranial pulsatility using MRI, with respect to measurement, physiological and pathophysiological aspects.Two-dimensional phase contrast magnetic resonance imaging (2D PCMRI) was used to assess the pulsatile waveforms of cerebral arterial, venous and CSF flow. The repeatability was assessed in healthy young subjects. The 2D PCMRI measurements of cerebral arterial, venous and CSF pulsatility were generally repeatable but the pulsatility decreased systematically during the investigation. A method combining 2D PCMRI measurements with invasive CSF infusion tests to determine the magnitude and distribution of compliance within the craniospinal system was developed and applied in a group of healthy elderly. The intracranial space contained approximately two thirds of the total craniospinal compliance. The magnitude of craniospinal compliance was less than suggested in previous studies. The vascular hypothesis for multiple sclerosis was tested. Venous drainage in the internal jugular veins was compared between healthy controls and multiple sclerosis patients using 2D PCMRI. For both groups, a great variability in the internal jugular flow was observed but no pattern specific to multiple sclerosis could be found. Relationships between regional brain volumes and potential biomarkers of intracranial cardiac-related pulsatile

  2. Cerebral blood flow and intracranial pulsatility studied with MRI: measurement, physiological and pathophysiological aspects

    International Nuclear Information System (INIS)

    Waahlin, Anders

    2012-01-01

    During each cardiac cycle pulsatile arterial blood inflates the vascular bed of the brain, forcing cerebrospinal fluid (CSF) and venous blood out of the cranium. Excessive arterial pulsatility may be part of a harmful mechanism causing cognitive decline among elderly. Additionally, restricted venous flow from the brain is suggested as the cause of multiple sclerosis. Addressing hypotheses derived from these observations requires accurate and reliable investigational methods. This work focused on assessing the pulsatile waveform of cerebral arterial, venous and CSF flows. The overall aim of this dissertation was to explore cerebral blood flow and intracranial pulsatility using MRI, with respect to measurement, physiological and pathophysiological aspects.Two-dimensional phase contrast magnetic resonance imaging (2D PCMRI) was used to assess the pulsatile waveforms of cerebral arterial, venous and CSF flow. The repeatability was assessed in healthy young subjects. The 2D PCMRI measurements of cerebral arterial, venous and CSF pulsatility were generally repeatable but the pulsatility decreased systematically during the investigation. A method combining 2D PCMRI measurements with invasive CSF infusion tests to determine the magnitude and distribution of compliance within the craniospinal system was developed and applied in a group of healthy elderly. The intracranial space contained approximately two thirds of the total craniospinal compliance. The magnitude of craniospinal compliance was less than suggested in previous studies. The vascular hypothesis for multiple sclerosis was tested. Venous drainage in the internal jugular veins was compared between healthy controls and multiple sclerosis patients using 2D PCMRI. For both groups, a great variability in the internal jugular flow was observed but no pattern specific to multiple sclerosis could be found. Relationships between regional brain volumes and potential biomarkers of intracranial cardiac-related pulsatile

  3. On the interpretation of the independent components underlying the abdominal phonogram: a study of their physiological relevance

    International Nuclear Information System (INIS)

    Jiménez-González, A; James, C J

    2012-01-01

    Recorded by positioning a sensitive acoustic sensor over the maternal womb, the abdominal phonogram is a signal that contains valuable information for foetal surveillance (e.g. heart rate), which is hidden by maternal and environmental sources. To recover such information, previous work used single-channel independent component analysis (SCICA) to separate the abdominal phonogram into statistically independent components (ICs) that, once acquired, must be objectively associated with the real sources underlying the abdominal phonogram—either physiological or environmental. This is a typical challenge for blind source separation methodologies and requires further research on the signals of interest to find a suitable solution. Here, we have conducted a joint study on 75 sets of ICs by means of statistical, spectral, complexity and time-structure analysis methods. As a result, valuable and consistent characteristics of the components separated from the abdominal phonogram by SCICA have been revealed: (1) the ICs are spectrally disjoint and sorted according to their frequency content, (2) only the ICs with lower frequency content present strong regular patterns and (3) such regular patterns are driven by well-known physiological processes given by the maternal breathing rate, the maternal heart rate and the foetal heart rate. This information was so promising that it has been used in current work for automatic classification of ICs and recovery of the traces of the physiological sources underlying the abdominal phonogram. Future work will look for the extraction of information useful for surveillance (e.g. heart rate), not only about foetal well-being, but also about maternal condition. (paper)

  4. Cadmium toxicity investigated at the physiological and biophysical levels under environmentally relevant conditions using the aquatic model plant Ceratophyllum demersum

    Czech Academy of Sciences Publication Activity Database

    Andresen, Elisa; Kappel, S.; Stärk, H.-J.; Riegger, U.; Borovec, Jakub; Mattusch, J.; Heinz, A.; Schmelzer, C.E.H.; Matoušková, Šárka; Dickinson, B.; Küpper, Hendrik

    2016-01-01

    Roč. 210, č. 4 (2016), s. 1244-1258 ISSN 0028-646X Institutional support: RVO:60077344 ; RVO:67985831 Keywords : Ceratophyllum demersum * Environmentally relevant * Light-harvesting complexes (LHCs) * Toxic metals Subject RIV: CE - Biochemistry; DD - Geochemistry (GLU-S) Impact factor: 7.330, year: 2016

  5. Corticotropin-releasing factor: effect on cerebral blood flow in physiologic and ischaemic conditions.

    Science.gov (United States)

    De Michele, Manuela; Touzani, Omar; Foster, Alan C; Fieschi, Cesare; Sette, Giuliano; McCulloch, James

    2005-09-01

    The expression of corticotrophin-releasing factor (CRF) receptors in cerebral arteries and arterioles suggests that CRF may modulate cerebral blood flow (CBF). In the present study, the effects of CRF, CRF-like peptides and the CRF broad spectrum antagonist DPhe-CRF on CBF have been investigated under normal physiologic conditions and in the margins of focal ischaemic insult. The experiments were carried out in anaesthetised and ventilated rats. Changes in CBF after subarachnoid microapplication of CRF and related peptides were assessed with a laser-Doppler flowmetry (LDF) probe. In the ischaemic animals, agents were injected approximately 60 minutes after permanent middle cerebral artery occlusion (MCAo). Microapplication of CRF and related peptides in normal rats into the subarachnoid space produced sustained concentration-dependent increases in CBF. This effect was attenuated by co-application with DPhe-CRF, which did not alter CBF itself. A second microapplication of CRF 30 min after the first failed to produce increases in CBF in normal animals. Microapplication of CRF in the subarachnoid space overlying the ischaemic cortex effected minor increases in CBF whereas D-Phe-CRF had no significant effect on CBF. Activation of the CRF peptidergic system increases CBF in the rat. Repeated activation of CRF receptors results in tachyphylaxis of the vasodilator response. CRF vasodilator response is still present after MCAo in the ischaemic penumbra, suggesting that the CRF peptidergic system may modulate CBF in ischaemic stroke.

  6. Physiological assessment of coronary lesion severity: fractional flow reserve versus nonhyperaemic indices.

    Science.gov (United States)

    Robertson, Keith E; Hennigan, Barry; Berry, Colin; Oldroyd, Keith G

    2015-08-01

    Coronary angiography alone cannot accurately identify the haemodynamic impact of a coronary artery stenosis. Current international guidelines for myocardial revascularization recommend that inducible ischaemia should be demonstrated before the consideration of percutaneous coronary intervention. Invasive physiological assessment of coronary stenosis severity has increasingly been utilized for this purpose and use of the best validated technique, fractional flow reserve (FFR), has been shown to improve clinical outcomes in patients with stable and unstable coronary artery disease. This has led to the use of FFR being recommended in international revascularization guidelines, despite which, clinical uptake has been limited. One potential reason for slow adoption has been the requirement for maximal hyperaemia at the time of FFR measurement, usually achieved by the administration of pharmacological vasodilators such as adenosine. In some healthcare systems, adenosine is expensive and, in addition, its use can be associated with significant, albeit transient, adverse effects that patients (and some operators) find uncomfortable. Consequently, several methods of nonhyperaemic lesion assessment and their potential role in decision making have been reported. In this review we will review and discuss the current evidence for hyperaemic and nonhyperaemic methods of lesion assessment. We will also look at hybrid strategies that utilize both hyperaemic and nonhyperaemic methods as a means of potentially maintaining diagnostic accuracy while minimizing the requirement for adenosine administration and discuss whether or not they represent viable clinical alternatives.

  7. Social defeat protocol and relevant biomarkers, implications for stress response physiology, drug abuse, mood disorders and individual stress vulnerability: a systematic review of the last decade.

    Science.gov (United States)

    Vasconcelos, Mailton; Stein, Dirson João; de Almeida, Rosa Maria M

    2015-01-01

    Social defeat (SD) in rats, which results from male intraspecific confrontations, is ethologically relevant and useful to understand stress effects on physiology and behavior. A systematic review of studies about biomarkers induced by the SD protocol and published from 2002 to 2013 was carried out in the electronic databases PubMed, Web of Knowledge and ScienceDirect. The search terms were: social defeat, rat, neurotrophins, neuroinflammatory markers, and transcriptional factors. Classical and recently discovered biomarkers were found to be relevant in stress-induced states. Findings were summarized in accordance to the length of exposure to stress: single, repeated, intermittent and continuous SD. This review found that the brain-derived neurotrophic factor (BDNF) is a distinct marker of stress adaptation. Along with glucocorticoids and catecholamines, BDNF seems to be important in understanding stress physiology. The SD model provides a relevant tool to study stress response features, development of addictive behaviors, clinic depression and anxiety, as well as individual differences in vulnerability and resilience to stress.

  8. Social defeat protocol and relevant biomarkers, implications for stress response physiology, drug abuse, mood disorders and individual stress vulnerability: a systematic review of the last decade

    Directory of Open Access Journals (Sweden)

    Mailton Vasconcelos

    2015-06-01

    Full Text Available Introduction: Social defeat (SD in rats, which results from male intraspecific confrontations, is ethologically relevant and useful to understand stress effects on physiology and behavior.Methods: A systematic review of studies about biomarkers induced by the SD protocol and published from 2002 to 2013 was carried out in the electronic databases PubMed, Web of Knowledge and ScienceDirect. The search terms were: social defeat, rat, neurotrophins, neuroinflammatory markers, and transcriptional factors.Results: Classical and recently discovered biomarkers were found to be relevant in stress-induced states. Findings were summarized in accordance to the length of exposure to stress: single, repeated, intermittent and continuous SD. This review found that the brain-derived neurotrophic factor (BDNF is a distinct marker of stress adaptation. Along with glucocorticoids and catecholamines, BDNF seems to be important in understanding stress physiology.Conclusion: The SD model provides a relevant tool to study stress response features, development of addictive behaviors, clinic depression and anxiety, as well as individual differences in vulnerability and resilience to stress.

  9. Effects of milk flow on the physiological and behavioural responses to feeding in an infant with hypoplastic left heart syndrome.

    Science.gov (United States)

    Pados, Britt F; Thoyre, Suzanne M; Estrem, Hayley H; Park, Jinhee; Knafl, George J; Nix, Brant

    2017-01-01

    Infants with hypoplastic left heart syndrome often experience difficulty with oral feeding, which contributes to growth failure, morbidity, and mortality. In response to feeding difficulty, clinicians often change the bottle nipple, and thus milk flow rate. Slow-flow nipples have been found to reduce the stress of feeding in other fragile infants, but no research has evaluated the responses of infants with hypoplastic left heart syndrome to alterations in milk flow. The purpose of this study was to evaluate the physiological and behavioural responses of an infant with hypoplastic left heart syndrome to bottle feeding with either a slow-flow (Dr. Brown's Preemie) or a standard-flow (Dr. Brown's Level 2) nipple. A single infant was studied for three feedings: two slow-flow and one standard-flow. Oral feeding, whether with a slow-flow or a standard-flow nipple, was distressing for this infant. During slow-flow feeding, she experienced more coughing events, whereas during standard-flow she experienced more gagging. Disengagement and compelling disorganisation were most common during feeding 3, that is slow-flow, which occurred 2 days after surgical placement of a gastrostomy tube. Clinically significant changes in heart rate, oxygen saturation, and respiratory rate were seen during all feedings. Heart rate was higher during standard-flow and respiratory rate was higher during slow-flow. Further research is needed to examine the responses of infants with hypoplastic left heart syndrome to oral feeding and to identify strategies that will support these fragile infants as they learn to feed. Future research should evaluate an even slower-flow nipple along with additional supportive feeding strategies.

  10. Coronary physiological assessment combining fractional flow reserve and index of microcirculatory resistance in patients undergoing elective percutaneous coronary intervention with grey zone fractional flow reserve.

    Science.gov (United States)

    Niida, Takayuki; Murai, Tadashi; Yonetsu, Taishi; Kanaji, Yoshihisa; Usui, Eisuke; Matsuda, Junji; Hoshino, Masahiro; Araki, Makoto; Yamaguchi, Masao; Hada, Masahiro; Ichijyo, Sadamitsu; Hamaya, Rikuta; Kanno, Yoshinori; Isobe, Mitsuaki; Kakuta, Tsunekazu

    2018-03-08

    The aim of this study is to investigate the association between fractional flow reserve (FFR) values and change in coronary physiological indices after elective percutaneous coronary intervention (PCI). Decision making for revascularization when FFR is 0.75-0.80 is controversial. A retrospective analysis was performed of 296 patients with stable angina pectoris who underwent physiological examinations before and after PCI. To investigate the differences of coronary flow improvement between territories with low-FFR (zone FFR (0.75-0.80), serial changes in physiological indices including mean transit time (Tmn), coronary flow reserve (CFR), and index of microcirculatory resistance (IMR) were compared between these two groups. Compared to low-FFR territories, grey-zone FFR territories showed significantly lower prevalence of Tmn shortening, CFR improvement, and decrease in IMR (Tmn shorting, 63.9% vs. 87.0%, P 51.3% vs. 63.3%, P = .040) and lower extent of their absolute changes (Tmn shorting, 0.06 (-0.03 to 0.16) vs. 0.22 (0.07-0.45), P zone FFR. Physiological assessment combining FFR and IMR may help identify patients who may benefit by PCI, particularly those in the grey zone. © 2018 Wiley Periodicals, Inc.

  11. Exploratory studies of flowing liquid metal divertor options for fusion-relevant magnetic fields in the MTOR facility

    International Nuclear Information System (INIS)

    Ying, A.Y.; Abdou, M.A.; Morley, N.; Sketchley, T.; Woolley, R.; Burris, J.; Kaita, R.; Fogarty, P.; Huang, H.; Lao, X.; Narula, M.; Smolentsev, S.; Ulrickson, M.

    2004-01-01

    This paper reports on experimental findings on liquid metal (LM) free surface flows crossing complex magnetic fields. The experiments involve jet and film flows using GaInSn and are conducted at the UCLA MTOR facility. The goal of this study is to understand the magnetohydrodynamics (MHD) features associated with such a free surface flow in a fusion-relevant magnetic field environment, and determine what LM free surface flow option is most suitable for lithium divertor particle pumping and surface heat removal applications in a near-term experimental plasma device, such as NSTX. Experimental findings indicate that a steady transverse magnetic field, even with gradients typical of NSTX outer divertor conditions, stabilizes a LM jet flow--reducing turbulent disturbances and delaying jet breakup. Important insights into the MHD behavior of liquid metal films under NSTX-like environments are also presented. It is possible to establish an uphill liquid metal film flow on a conducting substrate, although the MHD drag experienced by the flow could be strong and cause the flow to pile-up under simulated NSTX magnetic field conditions. The magnetic field changes the turbulent film flow so that wave structures range from 2D column-type surface disturbances at regions of high magnetic field, to ordinary hydrodynamic turbulence wave structures at regions of low field strength at the outboard. Plans for future work are also presented

  12. Monoamine oxidase inhibitory activity in tobacco particulate matter: Are harman and norharman the only physiologically relevant inhibitors?

    Science.gov (United States)

    Truman, Penelope; Grounds, Peter; Brennan, Katharine A

    2017-03-01

    Monoamine oxidase inhibition is significant in smokers, but it is still unclear how the inhibition that is seen in the brains and bodies of smokers is brought about. Our aim was to test the contribution of the harman and norharman in tobacco smoke to MAO-A inhibition from tobacco smoke preparations, as part of a re-examination of harman and norharman as the cause of the inhibition of MAO-A inhibition in the brain. Tobacco smoke particulate matter and cigarette smoke particulate matter were prepared and the amounts of harman and norharman measured. The results were compared with the total monoamine oxidase-A inhibitory activity. At a nicotine concentration of 0.6μM (a "physiological" concentration in blood) the total monoamine oxidase-A inhibitory activity measured in these samples was sufficient to inhibit the enzyme by approximately 10%. Of this inhibitory activity, only a small proportion of the total was found to be due to harman and norharman. These results show that harman and norharman provide only a moderate contribution to the total monoamine oxidase-A inhibitory activity of tobacco smoke, perhaps under 10%. This suggests that other inhibitors (either known or unknown) may be more significant contributors to total inhibitory activity than has yet been established, and deserve closer examination. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Imaging the NADH:NAD+ Homeostasis for Understanding the Metabolic Response of Mycobacterium to Physiologically Relevant Stresses.

    Science.gov (United States)

    Bhat, Shabir A; Iqbal, Iram K; Kumar, Ashwani

    2016-01-01

    studies on mycobacterial physiology and will create new avenues of research for anti-tuberculosis drug discovery.

  14. Exploring liquid metal plasma facing component (PFC) concepts-Liquid metal film flow behavior under fusion relevant magnetic fields

    International Nuclear Information System (INIS)

    Narula, M.; Abdou, M.A.; Ying, A.; Morley, N.B.; Ni, M.; Miraghaie, R.; Burris, J.

    2006-01-01

    The use of fast moving liquid metal streams or 'liquid walls' as a plasma contact surface is a very attractive option and has been looked upon with considerable interest over the past several years, both by the plasma physics and fusion engineering programs. Flowing liquid walls provide an ever replenishing contact surface to the plasma, leading to very effective particle pumping and surface heat flux removal. A key feasibility issue for flowing liquid metal plasma facing component (PFC) systems, pertains to their magnetohydrodynamic (MHD) behavior under the spatially varying magnetic field environment, typical of a fusion device. MHD forces hinder the development of a smooth and controllable liquid metal flow needed for PFC applications. The present study builds up on the ongoing research effort at UCLA, directed towards providing qualitative and quantitative data on liquid metal free surface flow behavior under fusion relevant magnetic fields

  15. Dynamic flow-through approaches for metal fractionation in environmentally relevant solid samples

    DEFF Research Database (Denmark)

    Miró, Manuel; Hansen, Elo Harald; Chomchoei, Roongrat

    2005-01-01

    generations of flow-injection analysis. Special attention is also paid to a novel, robust, non-invasive approach for on-site continuous sampling of soil solutions, capitalizing on flow-through microdialysis, which presents itself as an appealing complementary approach to the conventional lysimeter experiments...

  16. Gene expression profiling of mucolipidosis type IV fibroblasts reveals deregulation of genes with relevant functions in lysosome physiology.

    Science.gov (United States)

    Bozzato, Andrea; Barlati, Sergio; Borsani, Giuseppe

    2008-04-01

    Mucolipidosis type IV (MLIV, MIM 252650) is an autosomal recessive lysosomal storage disorder that causes mental and motor retardation as well as visual impairment. The lysosomal storage defect in MLIV is consistent with abnormalities of membrane traffic and organelle dynamics in the late endocytic pathway. MLIV is caused by mutations in the MCOLN1 gene, which codes for mucolipin-1 (MLN1), a member of the large family of transient receptor potential (TRP) cation channels. Although a number of studies have been performed on mucolipin-1, the pathological mechanisms underlying MLIV are not fully understood. To identify genes that characterize pathogenic changes in mucolipidosis type IV, we compared the expression profiles of three MLIV and three normal skin fibroblasts cell lines using oligonucleotide microarrays. Genes that were differentially expressed in patients' cells were identified. 231 genes were up-regulated, and 116 down-regulated. Real-Time RT-PCR performed on selected genes in six independent MLIV fibroblasts cell lines was generally consistent with the microarray findings. This study allowed to evidence the modulation at the transcriptional level of a discrete number of genes relevant in biological processes which are altered in the disease such as endosome/lysosome trafficking, lysosome biogenesis, organelle acidification and lipid metabolism.

  17. Cadmium toxicity investigated at the physiological and biophysical levels under environmentally relevant conditions using the aquatic model plant Ceratophyllum demersum

    DEFF Research Database (Denmark)

    Andresen, Elisa; Kappel, Sophie; Stärk, Hans-Joachim

    2016-01-01

    Cadmium (Cd) is an important environmental pollutant and is poisonous to most organisms. We aimed to unravel the mechanisms of Cd toxicity in the model water plant Ceratophyllum demersum exposed to low (nM) concentrations of Cd as are present in nature. Experiments were conducted under environmen......Cadmium (Cd) is an important environmental pollutant and is poisonous to most organisms. We aimed to unravel the mechanisms of Cd toxicity in the model water plant Ceratophyllum demersum exposed to low (nM) concentrations of Cd as are present in nature. Experiments were conducted under...... environmentally relevant conditions, including nature-like light and temperature cycles, and a low biomass to water ratio. We measured chlorophyll (Chl) fluorescence kinetics, oxygen exchange, the concentrations of reactive oxygen species and pigments, metal binding to proteins, and the accumulation of starch...... and metals. The inhibition threshold concentration for most parameters was 20 nM. Below this concentration, hardly any stress symptoms were observed. The first site of inhibition was photosynthetic light reactions (the maximal quantum yield of photosystem II (PSII) reaction centre measured as Fv /Fm , light...

  18. Change in coronary blood flow after percutaneous coronary intervention in relation to baseline lesion physiology: results of the JUSTIFY-PCI study.

    Science.gov (United States)

    Nijjer, Sukhjinder S; Petraco, Ricardo; van de Hoef, Tim P; Sen, Sayan; van Lavieren, Martijn A; Foale, Rodney A; Meuwissen, Martijn; Broyd, Christopher; Echavarria-Pinto, Mauro; Al-Lamee, Rasha; Foin, Nicolas; Sethi, Amarjit; Malik, Iqbal S; Mikhail, Ghada W; Hughes, Alun D; Mayet, Jamil; Francis, Darrel P; Di Mario, Carlo; Escaned, Javier; Piek, Jan J; Davies, Justin E

    2015-06-01

    Percutaneous coronary intervention (PCI) aims to increase coronary blood flow by relieving epicardial obstruction. However, no study has objectively confirmed this and assessed changes in flow over different phases of the cardiac cycle. We quantified the change in resting and hyperemic flow velocity after PCI in stenoses defined physiologically by fractional flow reserve and other parameters. Seventy-five stenoses (67 patients) underwent paired flow velocity assessment before and after PCI. Flow velocity was measured over the whole cardiac cycle and the wave-free period. Mean fractional flow reserve was 0.68±0.02. Pre-PCI, hyperemic flow velocity is diminished in stenoses classed as physiologically significant compared with those classed nonsignificant (PPCI, resting flow velocity over the wave-free period increased little (5.6±1.6 cm/s) and significantly less than hyperemic flow velocity (21.2±3 cm/s; P0.80 had a significantly smaller gain (Δ4.6±2.3 cm/s; PPCI physiology is strongly associated with post-PCI increase in hyperemic coronary flow velocity. Hyperemic flow velocity increases 6-fold more when stenoses classed as physiologically significant undergo PCI than when nonsignificant stenoses are treated. Resting flow velocity measured over the wave-free period changes at least 4-fold less than hyperemic flow velocity after PCI. © 2015 American Heart Association, Inc.

  19. Change in Coronary Blood Flow After Percutaneous Coronary Intervention in Relation to Baseline Lesion Physiology Results of the JUSTIFY-PCI Study

    Science.gov (United States)

    Nijjer, Sukhjinder S.; Petraco, Ricardo; van de Hoef, Tim P.; Sen, Sayan; van Lavieren, Martijn A.; Foale, Rodney A.; Meuwissen, Martijn; Broyd, Christopher; Echavarria-Pinto, Mauro; Al-Lamee, Rasha; Foin, Nicolas; Sethi, Amarjit; Malik, Iqbal S.; Mikhail, Ghada W.; Hughes, Alun D.; Mayet, Jamil; Francis, Darrel P.; Di Mario, Carlo; Escaned, Javier; Piek, Jan J.; Davies, Justin E.

    2016-01-01

    Background Percutaneous coronary intervention (PCI) aims to increase coronary blood flow by relieving epicardial obstruction. However, no study has objectively confirmed this and assessed changes in flow over different phases of the cardiac cycle. We quantified the change in resting and hyperemic flow velocity after PCI in stenoses defined physiologically by fractional flow reserve and other parameters. Methods and Results Seventy-five stenoses (67 patients) underwent paired flow velocity assessment before and after PCI. Flow velocity was measured over the whole cardiac cycle and the wave-free period. Mean fractional flow reserve was 0.68±0.02. Pre-PCI, hyperemic flow velocity is diminished in stenoses classed as physiologically significant compared with those classed nonsignificant (PPCI, resting flow velocity over the wave-free period increased little (5.6±1.6 cm/s) and significantly less than hyperemic flow velocity (21.2±3 cm/s; P0.80 had a significantly smaller gain (Δ4.6±2.3 cm/s; PPCI physiology is strongly associated with post-PCI increase in hyperemic coronary flow velocity. Hyperemic flow velocity increases 6-fold more when stenoses classed as physiologically significant undergo PCI than when nonsignificant stenoses are treated. Resting flow velocity measured over the wave-free period changes at least 4-fold less than hyperemic flow velocity after PCI. PMID:26025217

  20. Highly selective deuteration of pharmaceutically relevant nitrogen-containing heterocycles: a flow chemistry approach.

    Science.gov (United States)

    Ötvös, Sándor B; Mándity, István M; Fülöp, Ferenc

    2011-08-01

    A simple and efficient flow-based technique is reported for the catalytic deuteration of several model nitrogen-containing heterocyclic compounds which are important building blocks of pharmacologically active materials. A continuous flow reactor was used in combination with on-demand pressure-controlled electrolytic D(2) production. The D(2) source was D(2)O, the consumption of which was very low. The experimental set-up allows the fine-tuning of pressure, temperature, and flow rate so as to determine the optimal conditions for the deuteration reactions. The described procedure lacks most of the drawbacks of the conventional batch deuteration techniques, and additionally is highly selective and reproducible.

  1. Progress in lattice Boltzmann methods for magnetohydrodynamic flows relevant to fusion applications

    International Nuclear Information System (INIS)

    Pattison, M.J.; Premnath, K.N.; Morley, N.B.; Abdou, M.A.

    2008-01-01

    In this paper, an approach to simulating magnetohydrodynamic (MHD) flows based on the lattice Boltzmann method (LBM) is presented. The dynamics of the flow are simulated using a so-called multiple relaxation time (MRT) lattice Boltzmann equation (LBE), in which a source term is included for the Lorentz force. The evolution of the magnetic induction is represented by introducing a vector distribution function and then solving an appropriate lattice kinetic equation for this function. The solution of both distribution functions are obtained through a simple, explicit, and computationally efficient stream-and-collide procedure. The use of the MRT collision term enhances the numerical stability over that of a single relaxation time approach. To apply the methodology to solving practical problems, a new extrapolation-based method for imposing magnetic boundary conditions is introduced and a technique for simulating steady-state flows with low magnetic Prandtl number is developed. In order to resolve thin layers near the walls arising in the presence of high magnetic fields, a non-uniform gridding strategy is introduced through an interpolated-streaming step applied to both distribution functions. These advances are particularly important for applications in fusion engineering where liquid metal flows with low magnetic Prandtl numbers and high Hartmann numbers are introduced. A number of MHD benchmark problems, under various physical and geometrical conditions are presented, including 3-D MHD lid driven cavity flow, high Hartmann number flows and turbulent MHD flows, with good agreement with prior data. Due to the local nature of the method, the LBM also demonstrated excellent performance on parallel machines, with almost linear scaling up to 128 processors for a MHD flow problem

  2. Relationship of goat milk flow emission variables with milking routine, milking parameters, milking machine characteristics and goat physiology.

    Science.gov (United States)

    Romero, G; Panzalis, R; Ruegg, P

    2017-11-01

    The aim of this paper was to study the relationship between milk flow emission variables recorded during milking of dairy goats with variables related to milking routine, goat physiology, milking parameters and milking machine characteristics, to determine the variables affecting milking performance and help the goat industry pinpoint farm and milking practices that improve milking performance. In total, 19 farms were visited once during the evening milking. Milking parameters (vacuum level (VL), pulsation ratio and pulsation rate, vacuum drop), milk emission flow variables (milking time, milk yield, maximum milk flow (MMF), average milk flow (AVMF), time until 500 g/min milk flow is established (TS500)), doe characteristics of 8 to 10 goats/farm (breed, days in milk and parity), milking practices (overmilking, overstripping, pre-lag time) and milking machine characteristics (line height, presence of claw) were recorded on every farm. The relationships between recorded variables and farm were analysed by a one-way ANOVA analysis. The relationships of milk yield, MMF, milking time and TS500 with goat physiology, milking routine, milking parameters and milking machine design were analysed using a linear mixed model, considering the farm as the random effect. Farm was significant (Pfarms, being similar to those recommended in scientific studies. Few milking parameters and milking machine characteristics affected the tested variables: average vacuum level only showed tendency on MMF, and milk pipeline height on TS500. Milk yield (MY) was mainly affected by parity, as the interaction of days in milk with parity was also significant. Milking time was mainly affected by milk yield and breed. Also significant were parity, the interaction of days in milk with parity and overstripping, whereas overmilking showed a slight tendency. We concluded that most of the studied variables were mainly related to goat physiology characteristics, as the effects of milking parameters and

  3. Physiological and morphological determinants of maximal expiratory flow in chronic obstructive lung disease

    NARCIS (Netherlands)

    H.A.W.M. Tiddens (Harm); J.M. Bogaard (Jan); J.C. de Jongste (Johan); W.C.J. Hop (Wim); H.O. Coxson (Harvey); P.D. Pare

    1996-01-01

    textabstractMaximal expiratory flow in chronic obstructive pulmonary disease (COPD) could be reduced by three different mechanisms; loss of lung elastic recoil, decreased airway conductance upstream of flow-limiting segments; and increased collapsibility of airways.

  4. Development of an ex vivo retention model simulating bioadhesion in the oral cavity using human saliva and physiologically relevant irrigation media

    DEFF Research Database (Denmark)

    Madsen, Katrine D.; Sander, Camilla; Baldursdottir, Stefania

    2013-01-01

    In recent years, there has been a particular interest in bioadhesive formulations for oromucosal drug delivery as this may promote prolonged local therapy and enhanced systemic effect. Saliva plays a vital role in oromucosal drug absorption by dissolving the drug and presenting it to the mucosal...... in the oral cavity. Thus we aimed at developing an advanced ex vivo buccal retention model, with focus on choosing a physiologically relevant irrigation media closely resembling human saliva. Spray dried chitosan microparticles containing metformin hydrochloride as an example of a small hydrophilic drug, were...... employed as bioadhesive formulations. Chewing-stimulated human whole saliva was collected and characterized for use in retention studies in comparison with four artificial irrigation media; phosphate buffer, Saliva Orthana(®), porcine gastric mucin base media (PGM3), and xanthan gum based media (XG2...

  5. Relevant parameters in the micro silica selection for the self-flowing ultra-low cement castables production

    International Nuclear Information System (INIS)

    Studart, A.R.; Pandolfelli, V.C.; Rodrigues, J.A.; Vendrasco, S.L.

    1997-01-01

    Self-flowing ultra-low cement castables typically contain a large fraction of the particles, usually fume silica, which increase their flowability and mechanical strength at low temperatures. Fume silicas available in the market differ mainly from their amount of impurities. It is assumed that the content of soluble alkali and free carbon containing in this raw-material affects strongly the processing of self-flowing castable. In this work high alumina castables with gap-sized particle size distribution were prepared to evaluate their flowability, workability and mechanical strength for each sort of fume silica studied. It was observed that the amount of impurities affects both deflocculation and setting time of the castables and their cold and hot mechanical strength. Considerations regarding the physical and chemical characteristics relevant for selecting fume silicas for the production of self-flowing castables are presented and discussed. (author)

  6. Relevance of free cash flow as a measure of generating value for owners

    Directory of Open Access Journals (Sweden)

    Bešlić Ivana

    2014-01-01

    Full Text Available In the new economy or knowledge economy the main goal of any company should be directed towards the achievement of the business in the interest of the owners, or generating the value for owners. In dynamic business environment, an effective performance measurement system is key determinant of successful implementation of corporate strategy, growth and survival of the company. Modern performance measures should provide an accurate assessment of the intrinsic value of the company, as well as the value for the owners (shareholders. The essence is maximizing the immanent or guaranteed value of the company. The immanent value is the value of a company based on internal evaluation (assessment discounted cash flows or expected cash flow in the future by the management team. Corporate managers in Serbia are facing the challenge of increasingly efficient capital markets and the competition in the future, which requires the implementation of a value oriented corporate governance, therefore this paper presents FCF (Free Cash Flow methodology of valuation. Free cash flow (FCF is the amount of cash available for owners of the company after the necessary investments in fixed assets and working capital to maintain the current scope of activities and support to planning.

  7. The Value Relevance of Dirty Surplus Accounting Flows in the Netherlands

    NARCIS (Netherlands)

    Wang, Y.; Buijink, W.F.J.; Eken Ra, R.C.W.

    2003-01-01

    Recently the Dutch financial reporting standard setters have taken steps to make dirty surplus accounting flows more visible to parties outside firms, either by eliminating their possibility or by requiring comprehensive income type statements. These steps are presumably based on the idea that dirty

  8. Characterization of Silver Nanoparticles under Environmentally Relevant Conditions Using Asymmetrical Flow Field-Flow Fractionation (AF4.

    Directory of Open Access Journals (Sweden)

    Min-Hee Jang

    Full Text Available The development of methods to monitor manufactured nanomaterials in the environment is one of the crucial areas for the assessment of their risk. More specifically, particle size analysis is a key element, because many properties of nanomaterial are size dependent. The sizing of nanomaterials in real environments is challenging due to their heterogeneity and reactivity with other environmental components. In this study, the fractionation and characterization of a mixture of polyvinylpyrrolidone-coated silver nanoparticles (PVP-AgNPs of three different sizes were investigated using asymmetrical flow field-flow fractionation (AF4 coupled with UV-Vis spectrophotometry. In particular, the effects of electrolyte composition and natural organic matter (NOM on the particle size and stability were evaluated. The fractogram peaks (i.e., stability of three different AgNPs decreased in the presence of both 10 mM NaCl and 10 mM CaCl2, while increased with increasing concentration of humic acid (HA. In addition, the hydrodynamic diameters of AgNPs in both electrolytes slightly increased with an increase of HA concentration, suggesting the adsorption (coating of HA onto the particle surface. It is also interesting to note that an increase in the particle size depended on the types of electrolyte, which could be explained by the conformational characteristics of the adsorbed HA layers. Consistent these results, AgNPs suspended in lake water containing relatively high concentration of organic carbon (TOC showed higher particle stability and larger particle size (i.e., by approximately 4 nm than those in river water. In conclusion, the application of AF4 coupled with highly sensitive detectors could be a powerful method to characterize nanoparticles in natural waters.

  9. Characterization of Silver Nanoparticles under Environmentally Relevant Conditions Using Asymmetrical Flow Field-Flow Fractionation (AF4)

    Science.gov (United States)

    Jang, Min-Hee; Lee, Seungho; Hwang, Yu Sik

    2015-01-01

    The development of methods to monitor manufactured nanomaterials in the environment is one of the crucial areas for the assessment of their risk. More specifically, particle size analysis is a key element, because many properties of nanomaterial are size dependent. The sizing of nanomaterials in real environments is challenging due to their heterogeneity and reactivity with other environmental components. In this study, the fractionation and characterization of a mixture of polyvinylpyrrolidone-coated silver nanoparticles (PVP-AgNPs) of three different sizes were investigated using asymmetrical flow field-flow fractionation (AF4) coupled with UV-Vis spectrophotometry. In particular, the effects of electrolyte composition and natural organic matter (NOM) on the particle size and stability were evaluated. The fractogram peaks (i.e., stability) of three different AgNPs decreased in the presence of both 10 mM NaCl and 10mM CaCl2, while increased with increasing concentration of humic acid (HA). In addition, the hydrodynamic diameters of AgNPs in both electrolytes slightly increased with an increase of HA concentration, suggesting the adsorption (coating) of HA onto the particle surface. It is also interesting to note that an increase in the particle size depended on the types of electrolyte, which could be explained by the conformational characteristics of the adsorbed HA layers. Consistent these results, AgNPs suspended in lake water containing relatively high concentration of organic carbon (TOC) showed higher particle stability and larger particle size (i.e., by approximately 4nm) than those in river water. In conclusion, the application of AF4 coupled with highly sensitive detectors could be a powerful method to characterize nanoparticles in natural waters. PMID:26575993

  10. Demonstrating electromagnetic control of free-surface, liquid-metal flows relevant to fusion reactors

    Science.gov (United States)

    Hvasta, M. G.; Kolemen, E.; Fisher, A. E.; Ji, H.

    2018-01-01

    Plasma-facing components (PFC’s) made from solid materials may not be able to withstand the large heat and particle fluxes that will be produced within next-generation fusion reactors. To address the shortcomings of solid PFC’s, a variety of liquid-metal (LM) PFC concepts have been proposed. Many of the suggested LM-PFC designs rely on electromagnetic restraint (Lorentz force) to keep free-surface, liquid-metal flows adhered to the interior surfaces of a fusion reactor. However, there is very little, if any, experimental data demonstrating that free-surface, LM-PFC’s can actually be electromagnetically controlled. Therefore, in this study, electrical currents were injected into a free-surface liquid-metal that was flowing through a uniform magnetic field. The resultant Lorentz force generated within the liquid-metal affected the velocity and depth of the flow in a controllable manner that closely matched theoretical predictions. These results show the promise of electromagnetic control for LM-PFC’s and suggest that electromagnetic control could be further developed to adjust liquid-metal nozzle output, prevent splashing within a tokamak, and alter heat transfer properties for a wide-range of liquid-metal systems.

  11. Compromising σ-1 receptors at the endoplasmic reticulum render cytotoxicity to physiologically relevant concentrations of dopamine in a nuclear factor-κB/Bcl-2-dependent mechanism: potential relevance to Parkinson's disease.

    Science.gov (United States)

    Mori, Tomohisa; Hayashi, Teruo; Su, Tsung-Ping

    2012-06-01

    The endoplasmic reticulum (ER) chaperone σ-1 receptor (Sig-1R) is cytoprotective against ER stress-induced apoptosis. The level of Sig-1Rs in the brain was reported to be lower in early parkinsonian patients. Because dopamine (DA) toxicity is well known to be involved in the etiology of Parkinson's disease, we tested in this study whether a relationship might exist between Sig-1Rs and DA-induced cytotoxicity in a cellular model by using Chinese hamster ovary (CHO) cells. DA in physiological concentrations (e.g., lower than 10 μM) does not cause apoptosis. However, the same concentrations of DA cause apoptosis in Sig-1R knockdown CHO cells. In search of a mechanistic explanation, we found that unfolded protein response is not involved. Rather, the level of protective protein Bcl-2 is critically involved in this DA/Sig-1R knockdown-induced apoptosis. Specifically, the DA/Sig-1R knockdown causes a synergistic proteasomal conversion of nuclear factor κB (NF-κB) p105 to the active form of p50, which is known to down-regulate the transcription of Bcl-2. It is noteworthy that the DA/Sig-1R knockdown-induced apoptosis is blocked by the overexpression of Bcl-2. Our results therefore indicate that DA is involved in the activation of NF-κB and suggest that endogenous Sig-1Rs are tonically inhibiting the proteasomal conversion/activation of NF-κB caused by physiologically relevant concentrations of DA that would otherwise cause apoptosis. Thus, Sig-1Rs and associated ligands may represent new therapeutic targets for the treatment of parkinsonism.

  12. Study on the association between earnings management and value relevance based on the reporting method used for operating cash flows

    Directory of Open Access Journals (Sweden)

    Marilena Mironiuc

    2018-02-01

    Full Text Available This paper analyses the association between earnings management and value relevance of accounting information, for a number of 556 observations from a sample of 65 companies listed on the Bucharest Stock Exchange during a 10 year period: 2006-2015. Sampled companies are classified according to the method used for the reporting of operating cash flows. Findings confirm that entities using the indirect method have a higher level of discretionary accruals and are more tempted to opportunistically increase their earnings. As far as value relevance is concerned, results show that participants on the Romanian capital market place more weight on the information reported by entities experiencing higher levels of discretionary accruals.

  13. Numerical simulations of counterstreaming plasmas and their relevance to interhemispheric flows

    International Nuclear Information System (INIS)

    Singh, N.; Schunk, R.W.

    1983-01-01

    The collisionless expansion of ccounterstreaming plasmas has been studied by solving the self-consistent set of Vlasov and Poisson equations in one dimension. The motivation for the study is to elucidate some of the basic physical processes which may occur during the initial refilling of depleted flux tubes after a magnetic storm. The simulation geometry consisted of two high-density H + -O + -electron plasmas (conjugate ionospheres) separated by a low density H + -electron plasma (equatorial plasmasphere). The temporal evolution of the expandinng plasmas and the electrostatic potential in the region between the two sources hass the following characteristics. The initially minor H + ions rapidly flow out of the source regions, creating counterstreaming density shock fronts which propagate at the Sagdeev Mach number for ion acoustic shocks (Mapprox.1.6). However, the shocks are preceded by suprathermal forerunner ions, which are the first to fill the ''equatorial'' region. When the counterstreaming ion acoustic shocks collide, the density in the equatorial region becomes nearly a constant, twice the value of the density in the individual shocks. The electrostatic potential distribution from the source plasmas to the midpoint of the expansion region displays an interesting feature. A potential hill forms near the midpoint after the arrival of the main density shock fronts. This localized potential hill plays an important role in the thermalization of the ion streams and may occur in the equatorial plasmasphere after magnetic storms. The numerical simulations indicate that the ion beams in the counterstreaming plasmas are remarkably stable with respect to the ion acoustic instability, which is in agreement with the linear instability theory

  14. Microbial Eco-Physiology of the human intestinal tract: a flow cytometric approach

    NARCIS (Netherlands)

    Amor, Ben K.

    2004-01-01

    This thesis describes a multifaceted approach to further enhance our view of the complex human intestinal microbial ecosystem. This approach combines me advantages of flow cyrometry (FCM), a single cell and high-throughput technology, and molecular techniques that have proven themselves to be

  15. Physiological breakdown of Jeffrey six constant nanofluid flow in an endoscope with nonuniform wall

    Directory of Open Access Journals (Sweden)

    S. Nadeem

    2015-12-01

    Full Text Available This paper analyse the endoscopic effects of peristaltic nanofluid flow of Jeffrey six-constant fluid model in the presence of magnetohydrodynamics flow. The current problem is modeled in the cylindrical coordinate system and exact solutions are managed (where possible under low Reynolds number and long wave length approximation. The influence of emerging parameters on temperature and velocity profile are discussed graphically. The velocity equation is solved analytically by utilizing the homotopy perturbation technique strongly, while the exact solutions are computed from temperature equation. The obtained expressions for velocity , concentration and temperature is sketched during graphs and the collision of assorted parameters is evaluate for transform peristaltic waves. The solution depend on thermophoresis number Nt, local nanoparticles Grashof number Gr, and Brownian motion number Nb. The obtained expressions for the velocity, temperature, and nanoparticles concentration profiles are plotted and the impact of various physical parameters are investigated for different peristaltic waves.

  16. Behavioral and physiological adaptations to high-flow velocities in chubs (Gila spp.) native to Southwestern USA.

    Science.gov (United States)

    Moran, Clinton J; Gerry, Shannon P; O'Neill, Matthew W; Rzucidlo, Caroline L; Gibb, Alice C

    2018-05-18

    Morphological streamlining is often associated with physiological advantages for steady swimming in fishes. Though most commonly studied in pelagic fishes, streamlining also occurs in fishes that occupy high-flow environments. Before the installation of dams and water diversions, bonytail (Cyprinidae, Gila elegans ), a fish endemic to the Colorado River (USA), regularly experienced massive, seasonal flooding events. Individuals of G. elegans display morphological characteristics that may facilitate swimming in high-flow conditions, including a narrow caudal peduncle and a high aspect ratio caudal fin. We tested the hypothesis that these features improve sustained swimming performance in bonytail by comparing locomotor performance in G. elegans with that of the closely related roundtail chub ( Gila robusta ) and two non-native species, rainbow trout ( Oncorhynchus mykiss ) and smallmouth bass ( Micropterus dolomieu ), using a Brett-style respirometer and locomotor step-tests. Gila elegans had the lowest estimated drag coefficient and the highest sustained swimming speeds relative to the other three species. There were no detectible differences in locomotor energetics during steady swimming among the four species. When challenged by high-velocity water flows, the second native species examined in this study, G. robusta , exploited the boundary effects in the flow tank by pitching forward and bracing the pelvic and pectoral fins against the acrylic tank bottom to 'hold station'. Because G. robusta can station hold to prevent being swept downstream during high flows and G. elegans can maintain swimming speeds greater than those of smallmouth bass and rainbow trout with comparable metabolic costs, we suggest that management agencies could use artificial flooding events to wash non-native competitors downstream and out of the Colorado River habitat. © 2018. Published by The Company of Biologists Ltd.

  17. Development of an ex vivo retention model simulating bioadhesion in the oral cavity using human saliva and physiologically relevant irrigation media.

    Science.gov (United States)

    Madsen, Katrine D; Sander, Camilla; Baldursdottir, Stefania; Pedersen, Anne Marie L; Jacobsen, Jette

    2013-05-20

    In recent years, there has been a particular interest in bioadhesive formulations for oromucosal drug delivery as this may promote prolonged local therapy and enhanced systemic effect. Saliva plays a vital role in oromucosal drug absorption by dissolving the drug and presenting it to the mucosal surface. However, the rheological, chemical, and interfacial properties of this complex biological fluid may strongly affect the adhesion of bioadhesive formulations. There is a need for well characterized in vitro models to assess the bioadhesive properties of oral dosage forms for administration in the oral cavity. Thus we aimed at developing an advanced ex vivo buccal retention model, with focus on choosing a physiologically relevant irrigation media closely resembling human saliva. Spray dried chitosan microparticles containing metformin hydrochloride as an example of a small hydrophilic drug, were employed as bioadhesive formulations. Chewing-stimulated human whole saliva was collected and characterized for use in retention studies in comparison with four artificial irrigation media; phosphate buffer, Saliva Orthana(®), porcine gastric mucin base media (PGM3), and xanthan gum based media (XG2). Retention of metformin, applied as spray dried microparticles on porcine buccal mucosa, greatly depended on the characteristics of the irrigation media. When rheology of the irrigation media was examined, changes in retention profiles could be interpreted, as irrigation media containing mucin and xanthan gum possessed a higher viscosity than phosphate buffer, which led to longer retention of the drug due to better hydration of the mucosa and the spray dried microparticles. Metformin retention profiles were comparable when human saliva, Saliva Orthana(®), or PGM3 were used as irrigation media. Moreover, PGM3 displayed physico-chemical properties closest to those of human saliva with regard to pH, protein content and surface tension. Saliva Orthana(®) and PGM3 are therefore

  18. Semi-automatized segmentation method using image-based flow cytometry to study sperm physiology: the case of capacitation-induced tyrosine phosphorylation.

    Science.gov (United States)

    Matamoros-Volante, Arturo; Moreno-Irusta, Ayelen; Torres-Rodriguez, Paulina; Giojalas, Laura; Gervasi, María G; Visconti, Pablo E; Treviño, Claudia L

    2018-02-01

    Is image-based flow cytometry a useful tool to study intracellular events in human sperm such as protein tyrosine phosphorylation or signaling processes? Image-based flow cytometry is a powerful tool to study intracellular events in a relevant number of sperm cells, which enables a robust statistical analysis providing spatial resolution in terms of the specific subcellular localization of the labeling. Sperm capacitation is required for fertilization. During this process, spermatozoa undergo numerous physiological changes, via activation of different signaling pathways, which are not completely understood. Classical approaches for studying sperm physiology include conventional microscopy, flow cytometry and Western blotting. These techniques present disadvantages for obtaining detailed subcellular information of signaling pathways in a relevant number of cells. This work describes a new semi-automatized analysis using image-based flow cytometry which enables the study, at the subcellular and population levels, of different sperm parameters associated with signaling. The increase in protein tyrosine phosphorylation during capacitation is presented as an example. Sperm cells were isolated from seminal plasma by the swim-up technique. We evaluated the intensity and distribution of protein tyrosine phosphorylation in sperm incubated in non-capacitation and capacitation-supporting media for 1 and 18 h under different experimental conditions. We used an antibody against FER kinase and pharmacological inhibitors in an attempt to identify the kinases involved in protein tyrosine phosphorylation during human sperm capacitation. Semen samples from normospermic donors were obtained by masturbation after 2-3 days of sexual abstinence. We used the innovative technique image-based flow cytometry and image analysis tools to segment individual images of spermatozoa. We evaluated and quantified the regions of sperm where protein tyrosine phosphorylation takes place at the

  19. Competitive endothelial adhesion between Plasmodium falciparum isolates under physiological flow conditions

    Directory of Open Access Journals (Sweden)

    Molyneux Malcolm

    2009-09-01

    Full Text Available Abstract Background Sequestration of parasitized red blood cells in the microvasculature of major organs involves a sequence of events that is believed to contribute to the pathogenesis of severe falciparum malaria. Plasmodium falciparum infections are commonly composed of multiple subpopulations of parasites with varied adhesive properties. A key question is: do these subpopulations compete for adhesion to endothelium? This study investigated whether, in a laboratory model of cytoadherence, there is competition in binding to endothelium between pRBC infected with P. falciparum of variant adhesive phenotypes, particularly under flow conditions. Methods Four different P. falciparum isolates, of known adherence phenotypes, were matched in pairs, mixed in different proportions and allowed to bind to cultured human endothelium. Using in vitro competitive static and flow-based adhesion assays, that allow simultaneous testing of the adhesive properties of two different parasite lines, adherence levels of paired P. falciparum isolates were quantified and analysed using either non-parametric Wilcoxon's paired signed rank test or Student paired test. Results Study findings show that P. falciparum parasite lines show marked differences in the efficiency of adhesion to endothelium. Conclusion Plasmodium falciparum variants will compete for adhesion to endothelia and variants can be ranked by their efficiency of binding. These findings suggest that variants from a mixed infection will not show uniform cytoadherence and so may vary in their ability to cause disease.

  20. Functional Relevance of Coronary Artery Disease by Cardiac Magnetic Resonance and Cardiac Computed Tomography: Myocardial Perfusion and Fractional Flow Reserve

    Directory of Open Access Journals (Sweden)

    Gianluca Pontone

    2015-01-01

    Full Text Available Coronary artery disease (CAD is one of the leading causes of morbidity and mortality and it is responsible for an increasing resource burden. The identification of patients at high risk for adverse events is crucial to select those who will receive the greatest benefit from revascularization. To this aim, several non-invasive functional imaging modalities are usually used as gatekeeper to invasive coronary angiography, but the diagnostic yield of elective invasive coronary angiography remains unfortunately low. Stress myocardial perfusion imaging by cardiac magnetic resonance (stress-CMR has emerged as an accurate technique for diagnosis and prognostic stratification of the patients with known or suspected CAD thanks to high spatial and temporal resolution, absence of ionizing radiation, and the multiparametric value including the assessment of cardiac anatomy, function, and viability. On the other side, cardiac computed tomography (CCT has emerged as unique technique providing coronary arteries anatomy and more recently, due to the introduction of stress-CCT and noninvasive fractional flow reserve (FFR-CT, functional relevance of CAD in a single shot scan. The current review evaluates the technical aspects and clinical experience of stress-CMR and CCT in the evaluation of functional relevance of CAD discussing the strength and weakness of each approach.

  1. Advances in regional cerebral blood flow measurement and patho-physiological analysis by SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Odano, Ikuo [Niigata Univ. (Japan). School of Medicine

    1994-04-01

    Recently, two kinds of radiopharmaceuticals have been developed to represent the biodistribution of regional blood flow, which are N-isopropyl-p-[[sup 123]I]iodoamphetamine (IMP) and [sup 99m]Tc-hexamethylpropylene-amine-oxime (HMPAO). The charachteristics, clinical usage and imitation of these two radiolabeled agents are discussed. The advantage of [sup 123]I-IMP is that it has high first-pass extraction and long retention in brain tissue, hence it can be used to measure the absolute values of regional cerebral blood flow (rCBF). When the kinetics of [sup 123]I-IMP is assumed to be freely diffusible in the brain, its behavior is considered by 2-compartment model, especially which is assumed by the microsphere model in the early period after the i.v. injection of [sup 123]I-IMP. Comparing the rCBF measured by [sup 123]I-IMP with that by [sup 133]Xe inhalation SPECT method, we have to consider PaCO[sub 2] when both SPECT studies are performed, because PaCO[sub 2] is one of the big factors which make effects on the alteration of rCBF. [sup 123]I-IMP has an interesting character of the redistribution phenomenon which represrent the degree of ischemia in the cerebrovascular diseases. Distribution volume an important datum obtained by the SPECT study with [sup 123]I-IMP, which represent the degree of retention, i.e. binding potential of [sup 123]I-IMP in the brain tissue. I introduced the usage of the distribution volume of [sup 123]I-IMP, which was constructed in the rate constant square method, in the differential diagnosis of Parkinson's disease and progressive supranuclear palsy (PSP). The clinical usage of [sup 99m] Tc-HMPAT was mentioned, the advantage of which is the rapid fixation in the brain tissue and the distribution does not change for long time after the i.v. injection. Hence [sup 99m]Tc-HMPAO is used for the diagnosis of epileptic foci and certain loading tests such as balloon occlusion test, postural test and acetazolamide loading test. (author).

  2. Advances in regional cerebral blood flow measurement and patho-physiological analysis by SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Odano, Ikuo (Niigata Univ. (Japan). School of Medicine)

    1994-04-01

    Recently, two kinds of radiopharmaceuticals have been developed to represent the biodistribution of regional blood flow, which are N-isopropyl-p-[[sup 123]I]iodoamphetamine (IMP) and [sup 99m]Tc-hexamethylpropylene-amine-oxime (HMPAO). The charachteristics, clinical usage and imitation of these two radiolabeled agents are discussed. The advantage of [sup 123]I-IMP is that it has high first-pass extraction and long retention in brain tissue, hence it can be used to measure the absolute values of regional cerebral blood flow (rCBF). When the kinetics of [sup 123]I-IMP is assumed to be freely diffusible in the brain, its behavior is considered by 2-compartment model, especially which is assumed by the microsphere model in the early period after the i.v. injection of [sup 123]I-IMP. Comparing the rCBF measured by [sup 123]I-IMP with that by [sup 133]Xe inhalation SPECT method, we have to consider PaCO[sub 2] when both SPECT studies are performed, because PaCO[sub 2] is one of the big factors which make effects on the alteration of rCBF. [sup 123]I-IMP has an interesting character of the redistribution phenomenon which represrent the degree of ischemia in the cerebrovascular diseases. Distribution volume an important datum obtained by the SPECT study with [sup 123]I-IMP, which represent the degree of retention, i.e. binding potential of [sup 123]I-IMP in the brain tissue. I introduced the usage of the distribution volume of [sup 123]I-IMP, which was constructed in the rate constant square method, in the differential diagnosis of Parkinson's disease and progressive supranuclear palsy (PSP). The clinical usage of [sup 99m] Tc-HMPAT was mentioned, the advantage of which is the rapid fixation in the brain tissue and the distribution does not change for long time after the i.v. injection. Hence [sup 99m]Tc-HMPAO is used for the diagnosis of epileptic foci and certain loading tests such as balloon occlusion test, postural test and acetazolamide loading test. (author).

  3. Prognostic value of fractional flow reserve: linking physiologic severity to clinical outcomes.

    Science.gov (United States)

    Johnson, Nils P; Tóth, Gábor G; Lai, Dejian; Zhu, Hongjian; Açar, Göksel; Agostoni, Pierfrancesco; Appelman, Yolande; Arslan, Fatih; Barbato, Emanuele; Chen, Shao-Liang; Di Serafino, Luigi; Domínguez-Franco, Antonio J; Dupouy, Patrick; Esen, Ali M; Esen, Ozlem B; Hamilos, Michalis; Iwasaki, Kohichiro; Jensen, Lisette O; Jiménez-Navarro, Manuel F; Katritsis, Demosthenes G; Kocaman, Sinan A; Koo, Bon-Kwon; López-Palop, Ramón; Lorin, Jeffrey D; Miller, Louis H; Muller, Olivier; Nam, Chang-Wook; Oud, Niels; Puymirat, Etienne; Rieber, Johannes; Rioufol, Gilles; Rodés-Cabau, Josep; Sedlis, Steven P; Takeishi, Yasuchika; Tonino, Pim A L; Van Belle, Eric; Verna, Edoardo; Werner, Gerald S; Fearon, William F; Pijls, Nico H J; De Bruyne, Bernard; Gould, K Lance

    2014-10-21

    Fractional flow reserve (FFR) has become an established tool for guiding treatment, but its graded relationship to clinical outcomes as modulated by medical therapy versus revascularization remains unclear. The study hypothesized that FFR displays a continuous relationship between its numeric value and prognosis, such that lower FFR values confer a higher risk and therefore receive larger absolute benefits from revascularization. Meta-analysis of study- and patient-level data investigated prognosis after FFR measurement. An interaction term between FFR and revascularization status allowed for an outcomes-based threshold. A total of 9,173 (study-level) and 6,961 (patient-level) lesions were included with a median follow-up of 16 and 14 months, respectively. Clinical events increased as FFR decreased, and revascularization showed larger net benefit for lower baseline FFR values. Outcomes-derived FFR thresholds generally occurred around the range 0.75 to 0.80, although limited due to confounding by indication. FFR measured immediately after stenting also showed an inverse relationship with prognosis (hazard ratio: 0.86, 95% confidence interval: 0.80 to 0.93; p < 0.001). An FFR-assisted strategy led to revascularization roughly half as often as an anatomy-based strategy, but with 20% fewer adverse events and 10% better angina relief. FFR demonstrates a continuous and independent relationship with subsequent outcomes, modulated by medical therapy versus revascularization. Lesions with lower FFR values receive larger absolute benefits from revascularization. Measurement of FFR immediately after stenting also shows an inverse gradient of risk, likely from residual diffuse disease. An FFR-guided revascularization strategy significantly reduces events and increases freedom from angina with fewer procedures than an anatomy-based strategy. Copyright © 2014. Published by Elsevier Inc.

  4. Useful method to monitor the physiological effects of alcohol ingestion by combination of micro-integrated laser Doppler blood flow meter and arm-raising test.

    Science.gov (United States)

    Iwasaki, Wataru; Nogami, Hirofumi; Ito, Hiroki; Gotanda, Takeshi; Peng, Yao; Takeuchi, Satoshi; Furue, Masutaka; Higurashi, Eiji; Sawada, Renshi

    2012-10-01

    Alcohol has a variety of effects on the human body, affecting both the sympathetic and parasympathetic nervous system. We examined the peripheral blood flow of alcohol drinkers using a micro-integrated laser Doppler blood flow meter (micro-electromechanical system blood flow sensor). An increased heart rate and blood flow was recorded at the earlobe after alcohol ingestion, and we observed strong correlation between blood flow, heart rate, and breath alcohol content in light drinkers; but not heavy drinkers. We also found that the amplitude of pulse waves measured at the fingertip during an arm-raising test significantly decreased on alcohol consumption, regardless of the individual's alcohol tolerance. Our micro-electromechanical system blood flow sensor successfully detected various physiological changes in peripheral blood circulation induced by alcohol consumption.

  5. Is the presence of end-diastolic forward flow specific for restrictive right ventricular physiology in repaired tetralogy of Fallot?

    Science.gov (United States)

    Mori, Yoshiki; Murakami, Tomotaka; Inoue, Nao; Kaneko, Sachie; Nakashima, Yasumi; Koide, Masaaki

    2017-08-01

    End-diastolic forward flow (EDFF) is recognized as restrictive right ventricular physiology (r-RVP), but conflicting results have been reported about effects on the clinical outcome in repaired tetralogy of Fallot (r-TOF). We hypothesized that the EDFF by Doppler was not specific for diagnosing r-RVP. Sixty-two consecutive patients aged 15.7±11.6years who underwent cardiac catheterization were studied. Patients were divided according to the presence of EDFF (group 1: EDFF+, group 2: EDFF-) and RV size (group A: small RV, group B: large RV [>150ml/m 2 ]). Group 1 (n=23) had higher a right atrial pressure (RAP), pressure gradient between the RAP and pulmonary diastolic pressure (PDP), and atrial natriuretic peptide (ANP) levels than group 2. Four patients (17.4%) in group 1 and 89.7% of patients in group 2 had a normal RAP range (a wave<10mmHg). There were no differences in the RV volume, ejection fraction (EF), B-type natriuretic peptide levels, and severity of pulmonary regurgitation (PR) between groups 1 and 2. Group A had better RV and LVEF than group B, as well as a smaller LV size. The RAP in subgroup 1A was higher than that of the other 3 subgroups. Subgroup 1B had a similar RAP to group 2, and a lower PDP and a more severe PR than subgroup 1A. Patients with EDFF are associated with increased ANP levels. The presence of EDFF may not be specific for r-RVP, since it is observed in some TOF patients with low PDP (severe PR) and normal RAP. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Physiology for the pulmonary functional imager

    Energy Technology Data Exchange (ETDEWEB)

    Levin, David L., E-mail: levin.david@mayo.edu [Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905 (United States); Schiebler, Mark L. [Department of Radiology, UW-Madison School of Medicine and Public Health, 600 Highland Avenue, Madison, WI 53792-3252 (United States); Hopkins, Susan R., E-mail: shopkins@ucsd.edu [Division of Physiology 0623A, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093 (United States)

    2017-01-15

    Highlights: • An understanding of the relevant pulmonary physiology is crucial to functional lung imaging. • Spatial resolution for pulmonary functional imaging can be substantially less than that used for anatomic/clinical imaging. • Regional deformation of the lung under the influence of gravity significantly affects the measurement of pulmonary perfusion. • Large vessels identified on perfusion imaging do not represent local blood flow. • Pulmonary diseases are typically characterized by a change in the matching of ventilation and perfusion. - Abstract: As pulmonary functional imaging moves beyond the realm of the radiologist and physicist, it is important that imagers have a common language and understanding of the relevant physiology of the lung. This review will focus on key physiological concepts and pitfalls relevant to functional lung imaging.

  7. Physiology for the pulmonary functional imager

    International Nuclear Information System (INIS)

    Levin, David L.; Schiebler, Mark L.; Hopkins, Susan R.

    2017-01-01

    Highlights: • An understanding of the relevant pulmonary physiology is crucial to functional lung imaging. • Spatial resolution for pulmonary functional imaging can be substantially less than that used for anatomic/clinical imaging. • Regional deformation of the lung under the influence of gravity significantly affects the measurement of pulmonary perfusion. • Large vessels identified on perfusion imaging do not represent local blood flow. • Pulmonary diseases are typically characterized by a change in the matching of ventilation and perfusion. - Abstract: As pulmonary functional imaging moves beyond the realm of the radiologist and physicist, it is important that imagers have a common language and understanding of the relevant physiology of the lung. This review will focus on key physiological concepts and pitfalls relevant to functional lung imaging.

  8. Physiology of the fuel ethanol strain Saccharomyces cerevisiae PE-2 at low pH indicates a context-dependent performance relevant for industrial applications.

    Science.gov (United States)

    Della-Bianca, Bianca E; de Hulster, Erik; Pronk, Jack T; van Maris, Antonius J A; Gombert, Andreas K

    2014-12-01

    Selected Saccharomyces cerevisiae strains are used in Brazil to produce the hitherto most energetically efficient first-generation fuel ethanol. Although genome and some transcriptome data are available for some of these strains, quantitative physiological data are lacking. This study investigates the physiology of S. cerevisiae strain PE-2, widely used in the Brazilian fuel ethanol industry, in comparison with CEN.PK113-7D, a reference laboratory strain, focusing on tolerance to low pH and acetic acid stress. Both strains were grown in anaerobic bioreactors, operated as batch, chemostat or dynamic continuous cultures. Despite their different backgrounds, biomass and product formation by the two strains were similar under a range of conditions (pH 5 or pH cells, incubated at pH 1.5, indicated a superior survival of glucose-depleted PE-2 cells, when compared with either CEN.PK113-7D or a commercial bakers' strain. These results indicate that the sulfuric acid washing step, used in the fuel ethanol industry to decrease bacterial contamination due to non-aseptic operation, might have exerted an important selective pressure on the microbial populations present in such environments. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  9. Multiphase, multicomponent simulations and experiments of reactive flow, relevant for combining geologic CO2 sequestration with geothermal energy capture

    Science.gov (United States)

    Saar, Martin O.

    2011-11-01

    Understanding the fluid dynamics of supercritical carbon dioxide (CO2) in brine- filled porous media is important for predictions of CO2 flow and brine displacement during geologic CO2 sequestration and during geothermal energy capture using sequestered CO2 as the subsurface heat extraction fluid. We investigate multiphase fluid flow in porous media employing particle image velocimetry experiments and lattice-Boltzmann fluid flow simulations at the pore scale. In particular, we are interested in the motion of a drop (representing a CO2 bubble) through an orifice in a plate, representing a simplified porous medium. In addition, we study single-phase/multicomponent reactive transport experimentally by injecting water with dissolved CO2 into rocks/sediments typically considered for CO2 sequestration to investigate how resultant fluid-mineral reactions modify permeability fields. Finally, we investigate numerically subsurface CO2 and heat transport at the geologic formation scale.

  10. Intraocular pressure, blood pressure, and retinal blood flow autoregulation: a mathematical model to clarify their relationship and clinical relevance.

    Science.gov (United States)

    Guidoboni, Giovanna; Harris, Alon; Cassani, Simone; Arciero, Julia; Siesky, Brent; Amireskandari, Annahita; Tobe, Leslie; Egan, Patrick; Januleviciene, Ingrida; Park, Joshua

    2014-05-29

    This study investigates the relationship between intraocular pressure (IOP) and retinal hemodynamics and predicts how arterial blood pressure (BP) and blood flow autoregulation (AR) influence this relationship. A mathematical model is developed to simulate blood flow in the central retinal vessels and retinal microvasculature as current flowing through a network of resistances and capacitances. Variable resistances describe active and passive diameter changes due to AR and IOP. The model is validated by using clinically measured values of retinal blood flow and velocity. The model simulations for six theoretical patients with high, normal, and low BP (HBP-, NBP-, LBP-) and functional or absent AR (-wAR, -woAR) are compared with clinical data. The model predicts that NBPwAR and HBPwAR patients can regulate retinal blood flow (RBF) as IOP varies between 15 and 23 mm Hg and between 23 and 29 mm Hg, respectively, whereas LBPwAR patients do not adequately regulate blood flow if IOP is 15 mm Hg or higher. Hemodynamic alterations would be noticeable only if IOP changes occur outside of the regulating range, which, most importantly, depend on BP. The model predictions are consistent with clinical data for IOP reduction via surgery and medications and for cases of induced IOP elevation. The theoretical model results suggest that the ability of IOP to induce noticeable changes in retinal hemodynamics depends on the levels of BP and AR of the individual. These predictions might help to explain the inconsistencies found in the clinical literature concerning the relationship between IOP and retinal hemodynamics. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  11. Electro-osmotically actuated oscillatory flow of a physiological fluid on a porous microchannel subject to an external AC electric field having dissimilar frequencies

    Science.gov (United States)

    Misra, Jagadis C.; Chandra, Sukumar

    2014-04-01

    Electro-osmotic flow of a physiological fluid with prominent micropolar characteristics, flowing over a microchannel has been analyzed for a situation, where the system is subject to the action of an external AC electric field. In order to account for the rotation of the micro-particles suspended in the physiological fluid, the fluid has been treated as a micropolar fluid. The microchannel is considered to be bounded by two porous plates executing oscillatory motion. Such motion of the plates will normally induce oscillatory flow of the fluid. The governing equations of the fluid include a second-order partial differential equation depicting Gauss's law of electrical charge distributions and two other partial differential equations of second order that arise out of the laws of conservation of linear and angular momenta. These equations have been solved under the sole influence of electrokinetic forces, by using appropriate boundary conditions. This enabled us to determine explicit analytical expressions for the electro-osmotic velocity of the fluid and the microrotation of the suspended micro-particles. These expressions have been used to obtain numerical estimates of important physical variables associated with the oscillatory electro-osmotic flow of a blood sample inside a micro-bio-fluidic device. The numerical results presented in graphical form clearly indicate that the formation of an electrical double layer near the vicinity of the wall causes linear momentum to reduce. In contrast, the angular momentum increases with the enhancement of microrotation of the suspended microparticles. The study will find important applications in the validation of results of further experimental and numerical models pertaining to flow in micro-bio-fluidic devices. It will also be useful in the improvement of the design and construction of various micro-bio-fluidic devices.

  12. Flow pattern and cleaning performance of a stationary liquid jet operating at conditions relevant for industrial tank cleaning

    DEFF Research Database (Denmark)

    Feldung Damkjær, N.; Adler-Nissen, Jens; Jensen, B. B. B.

    2017-01-01

    jet was studied using a 19m3 tank and settings applicable to industrial operations; nozzle internal diameters, dN, of 2–5.5mm, cleaning distances, L, of 80–2490mm, and flow rates, Q, of 0.05–3.0m3h−1. Experimental data and model predictions of the behaviour of the jet when striking an unsoiled surface...

  13. Behavioural and physiological responses of brook trout Salvelinus fontinalis to midwinter flow reduction in a small ice-free mountain stream.

    Science.gov (United States)

    Krimmer, A N; Paul, A J; Hontela, A; Rasmussen, J B

    2011-09-01

    This study presents an experimental analysis of the effects of midwinter flow reduction (50-75%, reduction in discharge in 4 h daily pulses) on the physical habitat and on behaviour and physiology of overwintering brook trout Salvelinus fontinalis in a small mountain stream. Flow reduction did not result in significant lowering of temperature or formation of surface or subsurface ice. The main findings were (1) daily movement by S. fontinalis increased (c. 2·5-fold) during flow reduction, but was limited to small-scale relocations (reduced during flow reduction. (3) Although both experimental and reference fish did lose mass and condition during the experiment, no effects of flow reduction on stress indicators (blood cortisol or glucose) or bioenergetics (total body fat, water content or mass loss) were detected, probably because access to the preferred type of cover remained available. Like other salmonids, S. fontinalis moves little and seeks physical cover during winter. Unlike many of the more studied salmonids, however, this species overwinters successfully in small groundwater-rich streams that often remain ice-free, and this study identifies undercut banks as the critical winter habitat rather than substratum cover. © 2011 The Authors. Journal of Fish Biology © 2011 The Fisheries Society of the British Isles.

  14. Studies of heat transfer having relevance to nuclear reactor containment cooling by buoyancy-driven air flow

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, J. D.; Li, J.; Wang, J. [The Univ., of Manchester, Manchester (United Kingdom)

    2003-07-01

    Two separate effects experiments concerned with buoyancy-influenced convective heat transfer in vertical passages which have relevance to the problem of nuclear reactor containment cooling by means of buoyancy-driven airflow are described. A feature of each is that local values of heat transfer coefficient are determined on surfaces maintained at uniform temperature. Experimental results are presented which highlight the need for buoyancy-induced impairment of turbulent convective heat transfer to be accounted for in the design of such passive cooling systems. A strategy is presented for predicting the heat removal by combined convective and radiative heat transfer from a full scale nuclear reactor containment shell using such experimental results.

  15. Planned upgrade to the coaxial plasma source facility for high heat flux plasma flows relevant to tokamak disruption simulations

    International Nuclear Information System (INIS)

    Caress, R.W.; Mayo, R.M.; Carter, T.A.

    1995-01-01

    Plasma disruptions in tokamaks remain serious obstacles to the demonstration of economical fusion power. In disruption simulation experiments, some important effects have not been taken into account. Present disruption simulation experimental data do not include effects of the high magnetic fields expected near the PFCs in a tokamak major disruption. In addition, temporal and spatial scales are much too short in present simulation devices to be of direct relevance to tokamak disruptions. To address some of these inadequacies, an experimental program is planned at North Carolina State University employing an upgrade to the Coaxial Plasma Source (CPS-1) magnetized coaxial plasma gun facility. The advantages of the CPS-1 plasma source over present disruption simulation devices include the ability to irradiate large material samples at extremely high areal energy densities, and the ability to perform these material studies in the presence of a high magnetic field. Other tokamak disruption relevant features of CPS-1U include a high ion temperature, high electron temperature, and long pulse length

  16. Physics and (patho)physiology in confined flows: from colloidal patterns to cytoplasmic rheology and sickle cell anemia

    Science.gov (United States)

    Mahadevan, L.

    2015-03-01

    I will discuss a few problems that involve the interaction of fluids and solids in confined spaces. (i) Jamming in pressure-driven suspension flows that show a transition from Stokes flows to Darcy flows as the solids start to lock, as in evaporative patterning in colloids (e.g. coffee stain formation) .(ii) Jamming and clogging of red blood cells, as in sickle-cell pathophysiology, with implications for other diseases that involve jamming. (iii) The mechanical response of crowded networks of filaments bathed in a fluid, as in the cytoskeleton, that can be described by poroelasticity theory. In each case, I will show how simple theories of multiphase flow and deformation can be used to explain a range of experimental observations, while failing to account for others, along with some thoughts on how to improve them.

  17. Systemic-to-pulmonary collateral flow in patients with palliated univentricular heart physiology: measurement using cardiovascular magnetic resonance 4D velocity acquisition

    Directory of Open Access Journals (Sweden)

    Valverde Israel

    2012-04-01

    Full Text Available Abstract Background Systemic-to-pulmonary collateral flow (SPCF may constitute a risk factor for increased morbidity and mortality in patients with single-ventricle physiology (SV. However, clinical research is limited by the complexity of multi-vessel two-dimensional (2D cardiovascular magnetic resonance (CMR flow measurements. We sought to validate four-dimensional (4D velocity acquisition sequence for concise quantification of SPCF and flow distribution in patients with SV. Methods 29 patients with SV physiology prospectively underwent CMR (1.5 T (n = 14 bidirectional cavopulmonary connection [BCPC], age 2.9 ± 1.3 years; and n = 15 Fontan, 14.4 ± 5.9 years and 20 healthy volunteers (age, 28.7 ± 13.1 years served as controls. A single whole-heart 4D velocity acquisition and five 2D flow acquisitions were performed in the aorta, superior/inferior caval veins, right/left pulmonary arteries to serve as gold-standard. The five 2D velocity acquisition measurements were compared with 4D velocity acquisition for validation of individual vessel flow quantification and time efficiency. The SPCF was calculated by evaluating the disparity between systemic (aortic minus caval vein flows and pulmonary flows (arterial and venour return. The pulmonary right to left and the systemic lower to upper body flow distribution were also calculated. Results The comparison between 4D velocity and 2D flow acquisitions showed good Bland-Altman agreement for all individual vessels (mean bias, 0.05±0.24 l/min/m2, calculated SPCF (−0.02±0.18 l/min/m2 and significantly shorter 4D velocity acquisition-time (12:34 min/17:28 min,p 2; Fontan 0.62±0.82 l/min/m2 and not in controls (0.01 + 0.16 l/min/m2, (3 inverse relation of right/left pulmonary artery perfusion and right/left SPCF (Pearson = −0.47,p = 0.01 and (4 upper to lower body flow distribution trend related to the weight (r = 0.742, p  Conclusions 4D

  18. Reductions in dead space ventilation with nasal high flow depend on physiological dead space volume: metabolic hood measurements during sleep in patients with COPD and controls.

    Science.gov (United States)

    Biselli, Paolo; Fricke, Kathrin; Grote, Ludger; Braun, Andrew T; Kirkness, Jason; Smith, Philip; Schwartz, Alan; Schneider, Hartmut

    2018-05-01

    Nasal high flow (NHF) reduces minute ventilation and ventilatory loads during sleep but the mechanisms are not clear. We hypothesised NHF reduces ventilation in proportion to physiological but not anatomical dead space.11 subjects (five controls and six chronic obstructive pulmonary disease (COPD) patients) underwent polysomnography with transcutaneous carbon dioxide (CO 2 ) monitoring under a metabolic hood. During stable non-rapid eye movement stage 2 sleep, subjects received NHF (20 L·min -1 ) intermittently for periods of 5-10 min. We measured CO 2 production and calculated dead space ventilation.Controls and COPD patients responded similarly to NHF. NHF reduced minute ventilation (from 5.6±0.4 to 4.8±0.4 L·min -1 ; pspace ventilation (from 2.5±0.4 to 1.6±0.4 L·min -1 ; pspace ventilation correlated with baseline physiological dead space fraction (r 2 =0.36; pspace volume.During sleep, NHF decreases minute ventilation due to an overall reduction in dead space ventilation in proportion to the extent of baseline physiological dead space fraction. Copyright ©ERS 2018.

  19. Measurements of sediment temperatures, conductivity and heat flow in the North Atlantic and their relevance to radioactive waste disposal

    International Nuclear Information System (INIS)

    Noel, M.J.

    1984-01-01

    This report describes the methods which were used to measure sediment temperatures, conductivity and heat flow at ten stations in the northeast Atlantic. These have yielded data from a total of 53 individual penetrations. Surface heat fluxes are compared to the values predicted by crustal cooling models while sediment temperature profiles are examined for evidence of vertical pore water advection. No thermal evidence was found for advection through sediments in the Great Meteor East study area. However, non-linear temperature profiles may be evidence for rapid pore water advection at several locations within the King's Trough Flank study region. These results are critically assessed in terms of other factors which may give rise to the observed non-linear temperature profiles. (author)

  20. A steady-state continuous flow chamber for the study of daytime and nighttime chemistry under atmospherically relevant NO levels

    Science.gov (United States)

    Zhang, Xuan; Ortega, John; Huang, Yuanlong; Shertz, Stephen; Tyndall, Geoffrey S.; Orlando, John J.

    2018-05-01

    Experiments performed in laboratory chambers have contributed significantly to the understanding of the fundamental kinetics and mechanisms of the chemical reactions occurring in the atmosphere. Two chemical regimes, classified as high-NO vs. zero-NO conditions, have been extensively studied in previous chamber experiments. Results derived from these two chemical scenarios are widely parameterized in chemical transport models to represent key atmospheric processes in urban and pristine environments. As the anthropogenic NOx emissions in the United States have decreased remarkably in the past few decades, the classic high-NO and zero-NO conditions are no longer applicable to many regions that are constantly impacted by both polluted and background air masses. We present here the development and characterization of the NCAR Atmospheric Simulation Chamber, which is operated in steady-state continuous flow mode for the study of atmospheric chemistry under intermediate NO conditions. This particular chemical regime is characterized by constant sub-ppb levels of NO and can be created in the chamber by precise control of the inflow NO concentration and the ratio of chamber mixing to residence timescales. Over the range of conditions achievable in the chamber, the lifetime of peroxy radicals (RO2), a key intermediate from the atmospheric degradation of volatile organic compounds (VOCs), can be extended to several minutes, and a diverse array of reaction pathways, including unimolecular pathways and bimolecular reactions with NO and HO2, can thus be explored. Characterization experiments under photolytic and dark conditions were performed and, in conjunction with model predictions, provide a basis for interpretation of prevailing atmospheric processes in environments with intertwined biogenic and anthropogenic activities. We demonstrate the proof of concept of the steady-state continuous flow chamber operation through measurements of major first-generation products

  1. Testing of porous SiC with dense coating under relevant conditions for Flow Channel Insert application

    Energy Technology Data Exchange (ETDEWEB)

    Ordás, N., E-mail: nordas@ceit.es [CEIT and Tecnun (University of Navarra), Manuel de Lardizábal 15, 20018 San Sebastián (Spain); Bereciartu, A.; García-Rosales, C. [CEIT and Tecnun (University of Navarra), Manuel de Lardizábal 15, 20018 San Sebastián (Spain); Moroño, A.; Malo, M.; Hodgson, E.R. [CIEMAT, Avenida Complutense 22, 28040 Madrid (Spain); Abellà, J.; Colominas, S. [Institut Químic de Sarrià, University Ramon Llull, Via Augusta 390, 08017 Barcelona (Spain); Sedano, L. [CIEMAT, Avenida Complutense 22, 28040 Madrid (Spain)

    2014-10-15

    Highlights: • Porous SiC coated by CVD with a dense coating was developed for Flow Channel Inserts (FCI) in dual-coolant blanket concept. • Porous SiC was obtained following the sacrificial template technique, using Al{sub 2}O{sub 3} and Y{sub 2}O{sub 3} as sintering additives. • Flexural strength, thermal and electrical conductivity, and microstructure of uncoated and coated porous SiC are presented. • Adhesion of coating to porous SiC and its corrosion behavior under Pb-17.5Li at 700 °C are shown. - Abstract: Thermally and electrically insulating porous SiC ceramics are attractive candidates for Flow Channel Inserts (FCI) in dual-coolant blanket concepts thanks to its relatively inexpensive manufacturing route. To prevent tritium permeation and corrosion by Pb-15.7 a dense coating has to be applied on the porous SiC. Despite not having structural function, FCI must exhibit sufficient mechanical strength to withstand strong thermal gradients and thermo-electrical stresses during operation. This work summarizes the results on the development of coated porous SiC for FCI. Porous SiC was obtained following the sacrificial template technique, using Al{sub 2}O{sub 3} and Y{sub 2}O{sub 3} as sintering additives and a carbonaceous phase as pore former. Sintering was performed in inert gas at 1850–1950 °C during 15 min to 3 h, followed by oxidation at 650 °C to eliminate the carbonaceous phase. The most promising bulk materials were coated with a ∼30 μm thick dense SiC by CVD. Results on porosity, bending tests, thermal and electrical conductivity are presented. The microstructure of the coating, its adhesion to the porous SiC and its corrosion behavior under Pb-17.5Li are also shown.

  2. A steady-state continuous flow chamber for the study of daytime and nighttime chemistry under atmospherically relevant NO levels

    Directory of Open Access Journals (Sweden)

    X. Zhang

    2018-05-01

    Full Text Available Experiments performed in laboratory chambers have contributed significantly to the understanding of the fundamental kinetics and mechanisms of the chemical reactions occurring in the atmosphere. Two chemical regimes, classified as high-NO vs. zero-NO conditions, have been extensively studied in previous chamber experiments. Results derived from these two chemical scenarios are widely parameterized in chemical transport models to represent key atmospheric processes in urban and pristine environments. As the anthropogenic NOx emissions in the United States have decreased remarkably in the past few decades, the classic high-NO and zero-NO conditions are no longer applicable to many regions that are constantly impacted by both polluted and background air masses. We present here the development and characterization of the NCAR Atmospheric Simulation Chamber, which is operated in steady-state continuous flow mode for the study of atmospheric chemistry under intermediate NO conditions. This particular chemical regime is characterized by constant sub-ppb levels of NO and can be created in the chamber by precise control of the inflow NO concentration and the ratio of chamber mixing to residence timescales. Over the range of conditions achievable in the chamber, the lifetime of peroxy radicals (RO2, a key intermediate from the atmospheric degradation of volatile organic compounds (VOCs, can be extended to several minutes, and a diverse array of reaction pathways, including unimolecular pathways and bimolecular reactions with NO and HO2, can thus be explored. Characterization experiments under photolytic and dark conditions were performed and, in conjunction with model predictions, provide a basis for interpretation of prevailing atmospheric processes in environments with intertwined biogenic and anthropogenic activities. We demonstrate the proof of concept of the steady-state continuous flow chamber operation through measurements of major first

  3. Phun Week: Understanding Physiology

    Science.gov (United States)

    Limson, Mel; Matyas, Marsha Lakes

    2009-01-01

    Topics such as sports, exercise, health, and nutrition can make the science of physiology relevant and engaging for students. In addition, many lessons on these topics, such as those on the cardiovascular, respiratory, and digestive systems, align with national and state life science education standards. Physiology Understanding Week (PhUn…

  4. Physiological activation of the human cerebral cortex during auditory perception and speech revealed by regional increases in cerebral blood flow

    DEFF Research Database (Denmark)

    Lassen, N A; Friberg, L

    1988-01-01

    by measuring regional cerebral blood flow CBF after intracarotid Xenon-133 injection are reviewed with emphasis on tests involving auditory perception and speech, and approach allowing to visualize Wernicke and Broca's areas and their contralateral homologues in vivo. The completely atraumatic tomographic CBF...

  5. A study of unsteady physiological magneto-fluid flow and heat transfer through a finite length channel by peristaltic pumping.

    Science.gov (United States)

    Tripathi, Dharmendra; Bég, O Anwar

    2012-08-01

    Magnetohydrodynamic peristaltic flows arise in controlled magnetic drug targeting, hybrid haemodynamic pumps and biomagnetic phenomena interacting with the human digestive system. Motivated by the objective of improving an understanding of the complex fluid dynamics in such flows, we consider in the present article the transient magneto-fluid flow and heat transfer through a finite length channel by peristaltic pumping. Reynolds number is small enough and the wavelength to diameter ratio is large enough to negate inertial effects. Analytical solutions for temperature field, axial velocity, transverse velocity, pressure gradient, local wall shear stress, volume flowrate and averaged volume flowrate are obtained. The effects of the transverse magnetic field, Grashof number and thermal conductivity on the flow patterns induced by peristaltic waves (sinusoidal propagation along the length of channel) are studied using graphical plots. The present study identifies that greater pressure is required to propel the magneto-fluid by peristaltic pumping in comparison to a non-conducting Newtonian fluid, whereas, a lower pressure is required if heat transfer is effective. The analytical solutions further provide an important benchmark for future numerical simulations.

  6. Multiparameter flow cytometric remission is the most relevant prognostic factor for multiple myeloma patients who undergo autologous stem cell transplantation

    Science.gov (United States)

    Paiva, Bruno; Vidriales, Maria-Belén; Cerveró, Jorge; Mateo, Gema; Pérez, Jose J.; Montalbán, Maria A.; Sureda, Anna; Montejano, Laura; Gutiérrez, Norma C.; de Coca, Alfonso García; de las Heras, Natalia; Mateos, Maria V.; López-Berges, Maria C.; García-Boyero, Raimundo; Galende, Josefina; Hernández, Jose; Palomera, Luis; Carrera, Dolores; Martínez, Rafael; de la Rubia, Javier; Martín, Alejandro; Bladé, Joan; Lahuerta, Juan J.; Orfao, Alberto

    2008-01-01

    Minimal residual disease (MRD) assessment is standard in many hematologic malignancies but is considered investigational in multiple myeloma (MM). We report a prospective analysis of the prognostic importance of MRD detection by multiparameter flow cytometry (MFC) in 295 newly diagnosed MM patients uniformly treated in the GEM2000 protocol VBMCP/VBAD induction plus autologous stem cell transplantation [ASCT]). MRD status by MFC was determined at day 100 after ASCT. Progression-free survival (PFS; median 71 vs 37 months, P < .001) and overall survival (OS; median not reached vs 89 months, P = .002) were longer in patients who were MRD negative versus MRD positive at day 100 after ASCT. Similar prognostic differentiation was seen in 147 patients who achieved immunofixation-negative complete response after ASCT. Moreover, MRD− immunofixation-negative (IFx−) patients and MRD− IFx+ patients had significantly longer PFS than MRD+ IFx− patients. Multivariate analysis identified MRD status by MFC at day 100 after ASCT as the most important independent prognostic factor for PFS (HR = 3.64, P = .002) and OS (HR = 2.02, P = .02). Our findings demonstrate the clinical importance of MRD evaluation by MFC, and illustrate the need for further refinement of MM re-sponse criteria. This trial is registered at http://clinicaltrials.gov under identifier NCT00560053. PMID:18669875

  7. Functionalized Magnetic Resonance Contrast Agent Selectively Binds to Glycoprotein IIb/IIIa on Activated Human Platelets under Flow Conditions and Is Detectable at Clinically Relevant Field Strengths

    Directory of Open Access Journals (Sweden)

    Constantin von zur Mühlen

    2008-03-01

    Full Text Available Recent progress in molecular magnetic resonance imaging (MRI provides the opportunity to image cells and cellular receptors using microparticles of iron oxide (MPIOs. However, imaging targets on vessel walls remains challenging owing to the quantity of contrast agents delivered to areas of interest under shear stress conditions. We evaluated ex vivo binding characteristics of a functional MRI contrast agent to ligand-induced binding sites (LIBSs on activated glycoprotein IIb/IIIa receptors of human platelets, which were lining rupture-prone atherosclerotic plaques and could therefore facilitate detection of platelet-mediated pathology in atherothrombotic disease. MPIOs were conjugated to anti-LIBS single-chain antibodies (LIBS-MPIO or control antibodies (control MPIO. Ex vivo binding to human platelet-rich clots in a dose-dependent manner was confirmed on a 3 T clinical MRI scanner and by histology (p < .05 for LIBS-MPIO vs control MPIO. By using a flow chamber setup, significant binding of LIBS-MPIO to a platelet matrix was observed under venous and arterial flow conditions, but not for control MPIO (p < .001. A newly generated MRI contrast agent detects activated human platelets at clinically relevant magnetic field strengths and binds to platelets under venous and arterial flow conditions, conveying high payloads of contrast to specific molecular targets. This may provide the opportunity to identify vulnerable, rupture-prone atherosclerotic plaques via noninvasive MRI.

  8. Aquaporin-4 Functionality and Virchow-Robin Space Water Dynamics: Physiological Model for Neurovascular Coupling and Glymphatic Flow.

    Science.gov (United States)

    Nakada, Tsutomu; Kwee, Ingrid L; Igarashi, Hironaka; Suzuki, Yuji

    2017-08-18

    The unique properties of brain capillary endothelium, critical in maintaining the blood-brain barrier (BBB) and restricting water permeability across the BBB, have important consequences on fluid hydrodynamics inside the BBB hereto inadequately recognized. Recent studies indicate that the mechanisms underlying brain water dynamics are distinct from systemic tissue water dynamics. Hydrostatic pressure created by the systolic force of the heart, essential for interstitial circulation and lymphatic flow in systemic circulation, is effectively impeded from propagating into the interstitial fluid inside the BBB by the tightly sealed endothelium of brain capillaries. Instead, fluid dynamics inside the BBB is realized by aquaporin-4 (AQP-4), the water channel that connects astrocyte cytoplasm and extracellular (interstitial) fluid. Brain interstitial fluid dynamics, and therefore AQP-4, are now recognized as essential for two unique functions, namely, neurovascular coupling and glymphatic flow, the brain equivalent of systemic lymphatics.

  9. Nasal Physiology

    Science.gov (United States)

    ... Caregivers Contact ARS HOME ANATOMY Nasal Anatomy Sinus Anatomy Nasal Physiology Nasal Endoscopy Skull Base Anatomy Virtual Anatomy Disclosure ... Patient Education About this Website Font Size + - Home > ANATOMY > Nasal Physiology Nasal Anatomy Sinus Anatomy Nasal Physiology Nasal Endoscopy ...

  10. Immuno-flow cytometric detection of the ichthyotoxic dinoflagellates Gyrodinium aureolum and Gymnodinium nagasakiense: independence of physiological state

    Science.gov (United States)

    Vrieling, Engel G.; van de Poll, Willem H.; Vriezekolk, Gertie; Gieskes, Winfried W. C.

    1997-05-01

    The ichthyotoxic dinoflagellates Gyrodinium aureolum and Gymnodinium nagasakiense were cultured under different environmental conditions to test possible variability in immunochemical labelling intensity of cell-surface antigens using species-specific monoclonal antibodies. Variation of antigen abundance (which is directly related to labelling intensity) at the cell surface, determined by immuno-flow cytometry of cells labelled with FITC, appeared to be small but significant compared to control cultures. In general, a minor decrease in FIX fluorescence was recorded during exponential growth, followed by an increase during stationary growth. FITC fluorescence was correlated with cell size, shape and structure. This suggests a constant number of antigens per unit of cell surface. In all cultures, immunochemically labelled cells were distinguished clearly from unlabelled cells; immuno-flow cytometric identification is apparently not affected by growth conditions. Only at the end of the stationary growth phase in batch cultures did the FITC fluorescence values drop, which suggests that unhealthy, dying or lysing cells may either alter the composition of the cell surface or just fail to express the antigen.

  11. Toxic Effects of Ethyl Cinnamate on the Photosynthesis and Physiological Characteristics of Chlorella vulgaris Based on Chlorophyll Fluorescence and Flow Cytometry Analysis

    Science.gov (United States)

    Jiao, Yang; Ouyang, Hui-Ling; Jiang, Yu-Jiao; Kong, Xiang-Zhen; He, Wei; Liu, Wen-Xiu; Yang, Bin; Xu, Fu-Liu

    2015-01-01

    The toxic effects of ethyl cinnamate on the photosynthetic and physiological characteristics of Chlorella vulgaris were studied based on chlorophyll fluorescence and flow cytometry analysis. Parameters, including biomass, F v/F m (maximal photochemical efficiency of PSII), ФPSII (actual photochemical efficiency of PSII in the light), FDA, and PI staining fluorescence, were measured. The results showed the following: (1) The inhibition on biomass increased as the exposure concentration increased. 1 mg/L ethyl cinnamate was sufficient to reduce the total biomass of C. vulgaris. The 48-h and 72-h EC50 values were 2.07 mg/L (1.94–2.20) and 1.89 mg/L (1.82–1.97). (2) After 24 h of exposure to 2–4 mg/L ethyl cinnamate, the photosynthesis of C. vulgaris almost ceased, manifesting in ФPSII being close to zero. After 72 h of exposure to 4 mg/L ethyl cinnamate, the F v/F m of C. vulgaris dropped to zero. (3) Ethyl cinnamate also affected the cellular physiology of C. vulgaris, but these effects resulted in the inhibition of cell yield rather than cell death. Exposure to ethyl cinnamate resulted in decreased esterase activities in C. vulgaris, increased average cell size, and altered intensities of chlorophyll a fluorescence. Overall, esterase activity was the most sensitive variable. PMID:26101784

  12. Sodium bicarbonate causes dose-dependent increases in cerebral blood flow in infants and children with single ventricle physiology

    Science.gov (United States)

    Buckley, Erin M.; Naim, Maryam Y.; Lynch, Jennifer M.; Goff, Donna A.; Schwab, Peter J.; Diaz, Laura K.; Nicolson, Susan C.; Montenegro, Lisa M.; Lavin, Natasha A.; Durduran, Turgut; Spray, Thomas L.; Gaynor, J. William; Putt, Mary E.; Yodh, A.G.; Fogel, Mark A.; Licht, Daniel J.

    2013-01-01

    Background Sodium bicarbonate (NaHCO3) is a common treatment for metabolic acidemia, however little definitive information exists regarding its treatment efficacy and cerebral hemodynamic effects. This pilot observational study quantifies relative changes in cerebral blood flow (rCBF) and oxy and deoxy-hemoglobin concentrations (ΔHbO2 and ΔHb) due to bolus administration of NaHCO3 in patients with mild base deficits. Methods Infants and children with hypoplastic left heart syndrome (HLHS) were recruited prior to cardiac surgery. NaHCO3 was given as needed for treatment of base deficit. Diffuse optical spectroscopies were employed for 15 minutes post-injection to non-invasively monitor ΔHb, ΔHbO2 and rCBF relative to baseline prior to NaHCO3 administration. Results Twenty-two anesthetized and mechanically ventilated HLHS patients (1 day to 4 years old) received a median (interquartile range) dose of 1.1 (0.8, 1.8) mEq/kg NaHCO3 administered intravenously over 10–20 seconds to treat a base deficit of −4 (−6, −3) mEq/l. NaHCO3 caused significant dose-dependent increases in rCBF, however population averaged ΔHb or Δ4HbO2 compared to controls were not significant. Conclusions Dose-dependent increases in cerebral blood flow (CBF) caused by bolus NaHCO3 are an important consideration in vulnerable populations wherein risk of rapid CBF fluctuations does not outweigh the benefit of treating a base deficit. PMID:23403802

  13. Development and experimental evaluation of models for low capillary number two-phase flows in rough walled fractures relevant to natural gradient conditions

    International Nuclear Information System (INIS)

    Glass, R.J.; Yarrington, L.; Nicholl, M.J.

    1997-09-01

    The major results from SNL's Conceptual Model Development and Validation Task (WBS 1.2.5.4.6) as developed through exploration of small scale processes were synthesized in Glass et al. to give guidance to Performance Assessment on improving conceptual models for isothermal flow in unsaturated, fractured rock. There, pressure saturation and relative permeability curves for single fractures were proposed to be a function of both fracture orientation within the gravity field and initial conditions. We refer the reader to Glass et al. for a discussion of the implications of this behavior for Performance Assessment. The scientific research we report here substantiates this proposed behavior. We address the modeling of phase structure within fractures under natural gradient conditions relevant to unsaturated flow through fractures. This phase structure underlies the calculation of effective properties for individual fractures and hence fracture networks as required for Performance Assessment. Standard Percolation (SP) and Invasion Percolation (IP) approaches have been recently proposed to model the underlying phase saturation structures within the individual fractures during conditions of two-phase flow. Subsequent analysis of these structures yields effective two-phase pressure-saturation and relative permeability relations for the fracture. However, both of these approaches yield structures that are at odds with physical reality as we see in experiments and thus effective properties calculated from these structures are in error. Here we develop and evaluate a Modified Invasion Percolation (MIP) approach to better model quasi-static immiscible displacement in fractures. The effects of gravity, contact angle, local aperature field geometry, and local in-plane interfacial curvature between phases are included in the calculation of invasion pressure for individual sites in a discretized aperture field

  14. Application of carbon-11 labelled nicotine in the measurement of human cerebral blood flow and other physiological parameters

    International Nuclear Information System (INIS)

    Yokoi, Fuji; Hayashi, Tokishi; Iio, Masaaki; Hara, Toshihiko

    1993-01-01

    Using positron emission tomography (PET), we measured the regional cerebral blood flow (rCBF) in five normal human subjects after intravenous injection of carbon-11 labelled (R)nicotine. The rCBF of the same subjects was measured by PET using the C 15 O 2 inhalation steady-state method. The distribution of 11 C activity in the brain after injection of 11 C-(R)nicotine was almost equivalent to the CBF image obtaines with C 15 O 2 inhalation steady-state method. The kinetics of 11 C-(R)nicotine in the brain was analysed using a two-compartment model consisting of vascular and brain tissue compartments. The rCBF values obtained with 11 C-(R)nicotine were higher than with C 15 O 2 gas. It is possible that the relatively long fixed distribution of 11 C-(R)nicotine with a short uptake period allows stimulation studies by measurement of CBF to be performed with better photon flux and a longer imaging time than are possible with H 2 15 O. (orig.)

  15. 4D Flow Analysis of BAV-Related Fluid-Dynamic Alterations: Evidences of Wall Shear Stress Alterations in Absence of Clinically-Relevant Aortic Anatomical Remodeling

    Directory of Open Access Journals (Sweden)

    Filippo Piatti

    2017-06-01

    Full Text Available Bicuspid aortic valve (BAV is the most common congenital cardiac disease and is a foremost risk factor for aortopathies. Despite the genetic basis of BAV and of the associated aortopathies, BAV-related alterations in aortic fluid-dynamics, and particularly in wall shear stresses (WSSs, likely play a role in the progression of aortopathy, and may contribute to its pathogenesis. To test whether WSS may trigger aortopathy, in this study we used 4D Flow sequences of phase-contrast cardiac magnetic resonance imaging (CMR to quantitatively compare the in vivo fluid dynamics in the thoracic aorta of two groups of subjects: (i five prospectively enrolled young patients with normo-functional BAV and with no aortic dilation and (ii ten age-matched healthy volunteers. Through the semi-automated processing of 4D Flow data, the aortic bulk flow at peak systole was quantified, and WSSs acting on the endothelium of the ascending aorta were characterized throughout the systolic phase in terms of magnitude and time-dependency through a method recently developed by our group. Variables computed for each BAV patient were compared vs. the corresponding distribution of values obtained for healthy controls. In BAV patients, ascending aorta diameter was measured on cine-CMR images at baseline and at 3-year follow-up. As compared to controls, normo-functional BAV patients were characterized by minor bulk flow disturbances at peak systole. However, they were characterized by evident alterations of WSS distribution and peak values in the ascending aorta. In particular, in four BAV patients, who were characterized by right-left leaflet fusion, WSS peak values exceeded by 27–46% the 90th percentile of the distribution obtained for healthy volunteers. Only in the BAV patient with right-non-coronary leaflet fusion the same threshold was exceeded by 132%. Also, evident alterations in the time-dependency of WSS magnitude and direction were observed. Despite, these fluid

  16. International Union of Basic and Clinical Pharmacology Review: WNT/Frizzled signalling: receptor–ligand selectivity with focus on FZD-G protein signalling and its physiological relevance: IUPHAR Review 3

    Science.gov (United States)

    Dijksterhuis, J P; Petersen, J; Schulte, G

    2014-01-01

    The wingless/int1 (WNT)/Frizzled (FZD) signalling pathway controls numerous cellular processes such as proliferation, differentiation, cell-fate decisions, migration and plays a crucial role during embryonic development. Nineteen mammalian WNTs can bind to 10 FZDs thereby activating different downstream pathways such as WNT/β-catenin, WNT/planar cell polarity and WNT/Ca2+. However, the mechanisms of signalling specification and the involvement of heterotrimeric G proteins are still unclear. Disturbances in the pathways can lead to various diseases ranging from cancer, inflammatory diseases to metabolic and neurological disorders. Due to the presence of seven-transmembrane segments, evidence for coupling between FZDs and G proteins and substantial structural differences in class A, B or C GPCRs, FZDs were grouped separately in the IUPHAR GPCR database as the class FZD within the superfamily of GPCRs. Recently, important progress has been made pointing to a direct activation of G proteins after WNT stimulation. WNT/FZD and G protein coupling remain to be fully explored, although the basic observation supporting the nature of FZDs as GPCRs is compelling. Because the involvement of different (i) WNTs; (ii) FZDs; and (iii) intracellular binding partners could selectively affect signalling specification, in this review we present the current understanding of receptor/ligand selectivity of FZDs and WNTs. We pinpoint what is known about signalling specification and the physiological relevance of these interactions with special emphasis on FZD–G protein interactions. LINKED ARTICLESThis article is part of a themed section on Molecular Pharmacology of GPCRs. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-5 PMID:24032637

  17. Rice Physiology

    Science.gov (United States)

    P.A. Counce; Davidi R. Gealy; Shi-Jean Susana Sung

    2002-01-01

    Physiology occurs tn physical space through chemical reactions constrained by anatomy and morphology, yet guided by genetics. Physiology has been called the logic of life. Genes encode structural and fimcdonal proteins. These proteins are subsequently processed to produce enzymes that direct and govern the biomechanical processes involved in the physiology of the...

  18. Detailed Geological Modelling in Urban Areas focused on Structures relevant to the Near Surface Groundwater Flow in the context of Climatic Changes

    Science.gov (United States)

    Bach, T.; Pallesen, T. M.; Jensen, N. P.; Mielby, S.; Sandersen, P.; Kristensen, M.

    2015-12-01

    This case demonstrates a practical example from the city of Odense (DK) where new geological modeling techniques has been developed and used in the software GeoScene3D, to create a detailed voxel model of the anthropogenic layer. The voxel model has been combined with a regional hydrostratigraphic layer model. The case is part of a pilot project partly financed by VTU (Foundation for Development of Technology in the Danish Water Sector) and involves many different datatypes such as borehole information, geophysical data, human related elements (landfill, pipelines, basements, roadbeds etc). In the last few years, there has been increased focus on detailed geological modeling in urban areas. The models serve as important input to hydrological models. This focus is partly due to climate changes as high intensity rainfalls are seen more often than in the past, and water recharge is a topic too. In urban areas, this arises new challenges. There is a need of a high level of detailed geological knowledge for the uppermost zone of the soil, which typically are problematic due to practically limitations, especially when using geological layer models. Furthermore, to accommodate the need of a high detail, all relevant available data has to be used in the modeling process. Human activity has deeply changed the soil layers, e.g. by constructions as roadbeds, buildings with basements, pipelines, landfill etc. These elements can act as barriers or pathways regarding surface near groundwater flow and can attribute to local flooding or mobilization and transport of contaminants etc. A geological voxel model is built by small boxes (a voxel). Each box can contain several parameters, ex. lithology, transmissivity or contaminant concentration. Human related elements can be implemented using tools, which gives the modeler advanced options for making detailed small-scale models. This case demonstrates the workflow and the resulting geological model for the pilot area.

  19. Personalized physiological medicine.

    Science.gov (United States)

    Ince, Can

    2017-12-28

    This paper introduces the concept of personalized physiological medicine that is specifically directed at the needs of the critically ill patient. This differs from the conventional view of personalized medicine, characterized by biomarkers and gene profiling, instead focusing on time-variant changes in the pathophysiology and regulation of various organ systems and their cellular and subcellular constituents. I propose that personalized physiological medicine is composed of four pillars relevant to the critically ill patient. Pillar 1 is defined by the frailty and fitness of the patient and their physiological reserve to cope with the stress of critical illness and therapy. Pillar 2 involves monitoring of the key physiological variables of the different organ systems and their response to disease and therapy. Pillar 3 concerns the evaluation of the success of resuscitation by assessment of the hemodynamic coherence between the systemic and microcirculation and parenchyma of the organ systems. Finally, pillar 4 is defined by the integration of the physiological and clinical data into a time-learning adaptive model of the patient to provide feedback about the function of organ systems and to guide and assess the response to disease and therapy. I discuss each pillar and describe the challenges to research and development that will allow the realization of personalized physiological medicine to be practiced at the bedside for critically ill patients.

  20. Physiological parameters

    International Nuclear Information System (INIS)

    Natera, E.S.

    1998-01-01

    The physiological characteristics of man depend on the intake, metabolism and excretion of stable elements from food, water, and air. The physiological behavior of natural radionuclides and radionuclides from nuclear weapons testing and from the utilization of nuclear energy is believed to follow the pattern of stable elements. Hence information on the normal physiological processes occurring in the human body plays an important role in the assessment of the radiation dose received by man. Two important physiological parameters needed for internal dose determination are the pulmonary function and the water balance. In the Coordinated Research Programme on the characterization of Asian population, five participants submitted data on these physiological characteristics - China, India, Japan, Philippines and Viet Nam. During the CRP, data on other pertinent characteristics such as physical and dietary were simultaneously being collected. Hence, the information on the physiological characteristics alone, coming from the five participants were not complete and are probably not sufficient to establish standard values for the Reference Asian Man. Nonetheless, the data collected is a valuable contribution to this research programme

  1. Relevant Standards

    Indian Academy of Sciences (India)

    .86: Ethernet over LAPS. Standard in China and India. G.7041: Generic Framing Procedure (GFP). Supports Ethernet as well as other data formats (e.g., Fibre Channel); Protocol of ... IEEE 802.3x for flow control of incoming Ethernet data ...

  2. Human physiology in space

    Science.gov (United States)

    Vernikos, J.

    1996-01-01

    The universality of gravity (1 g) in our daily lives makes it difficult to appreciate its importance in morphology and physiology. Bone and muscle support systems were created, cellular pumps developed, neurons organised and receptors and transducers of gravitational force to biologically relevant signals evolved under 1g gravity. Spaceflight provides the only microgravity environment where systematic experimentation can expand our basic understanding of gravitational physiology and perhaps provide new insights into normal physiology and disease processes. These include the surprising extent of our body's dependence on perceptual information, and understanding the effect and importance of forces generated within the body's weightbearing structures such as muscle and bones. Beyond this exciting prospect is the importance of this work towards opening the solar system for human exploration. Although both appear promising, we are only just beginning to taste what lies ahead.

  3. Regulatory Physiology

    Science.gov (United States)

    Lane, Helen W.; Whitson, Peggy A.; Putcha, Lakshmi; Baker, Ellen; Smith, Scott M.; Stewart, Karen; Gretebeck, Randall; Nimmagudda, R. R.; Schoeller, Dale A.; Davis-Street, Janis

    1999-01-01

    As noted elsewhere in this report, a central goal of the Extended Duration Orbiter Medical Project (EDOMP) was to ensure that cardiovascular and muscle function were adequate to perform an emergency egress after 16 days of spaceflight. The goals of the Regulatory Physiology component of the EDOMP were to identify and subsequently ameliorate those biochemical and nutritional factors that deplete physiological reserves or increase risk for disease, and to facilitate the development of effective muscle, exercise, and cardiovascular countermeasures. The component investigations designed to meet these goals focused on biochemical and physiological aspects of nutrition and metabolism, the risk of renal (kidney) stone formation, gastrointestinal function, and sleep in space. Investigations involved both ground-based protocols to validate proposed methods and flight studies to test those methods. Two hardware tests were also completed.

  4. Mathematical physiology

    CERN Document Server

    Sneyd, James

    2009-01-01

    There has been a long history of interaction between mathematics and physiology. This book looks in detail at a wide selection of mathematical models in physiology, showing how physiological problems can be formulated and studied mathematically, and how such models give rise to interesting and challenging mathematical questions. With its coverage of many recent models it gives an overview of the field, while many older models are also discussed, to put the modern work in context. In this second edition the coverage of basic principles has been expanded to include such topics as stochastic differential equations, Markov models and Gibbs free energy, and the selection of models has also been expanded to include some of the basic models of fluid transport, respiration/perfusion, blood diseases, molecular motors, smooth muscle, neuroendrocine cells, the baroreceptor loop, turboglomerular oscillations, blood clotting and the retina. Owing to this extensive coverage, the second edition is published in two volumes. ...

  5. Physiological pseudomyopia.

    Science.gov (United States)

    Jones, R

    1990-08-01

    Objective refraction through plus fogging lenses and base-in prisms revealed that normally accommodation is not completely relaxed when the stimulus to accommodation is zero. The myopic shift in the refractive error due to this focus error of accommodation was defined as physiological pseudomyopia. Two previously established features of accommodation are responsible for this behavior: (1) accommodation acts as a proportional control system for steady-state responses; and (2) the rest focus of accommodation is nonzero. It is proposed that the hyperopic shift in refraction observed in cycloplegia is the result of elimination of physiological pseudomyopia.

  6. PERMCAT experiments with tritium at high helium flow rates relevant for the tritium extraction systems using the CAPER facility at TLK

    Energy Technology Data Exchange (ETDEWEB)

    Bükki-Deme, András, E-mail: andras.buekki-deme@kit.edu; Demange, David; Le, Thanh-Long; Fanghänel, Eleonore; Simon, Karl-Heinz

    2016-11-01

    Highlights: • We examined PERMCAT reactor efficiency processing tritiated water at high Helium carrier flow rates. • We have found that – as expected from previous studies – that the swamping ratio (ratio between the impurity and purge side flow rates) has a key effect on the decontamination factors. • On the other hand, some rather unexpected effects tend to show that the limiting phenomena of such specific operation of PERMCAT reactors (at high impurity flow rates, thus short residence time) lies on the kinetics of the isotope exchange reactions. - Abstract: Experiments are still necessary to consolidate the processes retained for the Tritium Extraction Systems of the European ITER Test Blanket Modules (TBM). A PERMCAT reactor combines a catalyst promoting isotope exchange reactions and a Pd/Ag membrane allowing tritium recovery from complex gaseous mixtures containing tritium in different chemical forms. Originally developed for the Tokamak Exhaust Processing, the PERMCAT process is also candidate to detritiate the water arising from an adsorption column installed in the TBM ancillary systems. We discuss the results of an extensive experimental campaign using a PERMCAT reactor to process Q{sub 2}O containing impurity gas mixtures at high flow rates. Two different experimental configurations were studied, namely PERMCAT stand-alone, and PERMCAT in combination with a zeolite molecular sieve bed (MSB, previously loaded with Q{sub 2}O) under regeneration. On the one hand, many expected behaviors were observed, such as the key influence of the swamping ratio (ratio between the impurity and purge side flow rates) on the decontamination factors. On the other hand, some rather unexpected effects tend to show that the limiting phenomena of such specific operation of PERMCAT reactors (at high flow rates, thus short residence time) lies on the kinetics of the isotope exchange reactions.

  7. Preliminary review of mass transfer and flow visualization studies and techniques relevant to the study of erosion-corrosion of reactor piping systems

    International Nuclear Information System (INIS)

    Kuzay, T.M.; Halle, H.J.; Kasza, K.E.

    1988-06-01

    This report provides some background information on the failed piping at the Surry-2 reactor; a summary of pertinent literature on mass transfer in related geometries; and a description of methodologies for visualization and erosion rate measurements in laboratory model studies that can provide greater insight into the role of flow geometry in erosion-corrosion. 18 refs., 9 figs., 1 tab

  8. Preliminary review of mass transfer and flow visualization studies and techniques relevant to the study of erosion-corrosion of reactor piping systems

    Energy Technology Data Exchange (ETDEWEB)

    Kuzay, T.M.; Halle, H.J.; Kasza, K.E.

    1988-06-01

    This report provides some background information on the failed piping at the Surry-2 reactor; a summary of pertinent literature on mass transfer in related geometries; and a description of methodologies for visualization and erosion rate measurements in laboratory model studies that can provide greater insight into the role of flow geometry in erosion-corrosion. 18 refs., 9 figs., 1 tab.

  9. Exercise physiology

    DEFF Research Database (Denmark)

    Kiens, Bente; Richter, Erik; Wojtaszewski, Jørgen

    2014-01-01

    The passing of Professor Bengt Saltin on September 12, 2014 truly marks the end of an era. As editor of the Journal of Applied Physiology and one of Bengt’s many collaborators and colleagues, I wanted the Journal to celebrate his many seminal contributions by means of an Editorial. Professor Bent...

  10. Temperature-Dependent Diffusion of H2SO4 in Air at Atmospherically Relevant Conditions: Laboratory Measurements Using Laminar Flow Technique.

    Czech Academy of Sciences Publication Activity Database

    Brus, David; Škrabalová, Lenka; Herrmann, E.; Olenius, T.; Trávníčková, Tereza; Makkonen, U.; Merikanto, J.

    2017-01-01

    Roč. 8, č. 7 (2017), č. článku 132. ISSN 2073-4433 R&D Projects: GA ČR GAP209/11/1342 Grant - others:ERC(FI) 257360; AFCE(FI) 272041; GA AF(FI) 288440 Institutional support: RVO:67985858 Keywords : diffusion coefficient * sulfuric acid * laminar flow tube Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 1.487, year: 2016

  11. Duration of Untreated Cardiac Arrest and Clinical Relevance of Animal Experiments: The Relationship Between the "No-Flow" Duration and the Severity of Post-Cardiac Arrest Syndrome in a Porcine Model.

    Science.gov (United States)

    Babini, Giovanni; Grassi, Luigi; Russo, Ilaria; Novelli, Deborah; Boccardo, Antonio; Luciani, Anita; Fumagalli, Francesca; Staszewsky, Lidia; Fiordaliso, Fabio; De Maglie, Marcella; Salio, Monica; Zani, Davide D; Letizia, Teresa; Masson, Serge; Luini, Mario V; Pravettoni, Davide; Scanziani, Eugenio; Latini, Roberto; Ristagno, Giuseppe

    2018-02-01

    The study investigated the effect of untreated cardiac arrest (CA), that is, "no-flow" time, on postresuscitation myocardial and neurological injury, and survival in a pig model to identify an optimal duration that adequately reflects the most frequent clinical scenario. An established model of myocardial infarction followed by CA and cardiopulmonary resuscitation was used. Twenty-two pigs were subjected to three no-flow durations: short (8-10 min), intermediate (12-13 min), and long (14-15 min). Left ventricular ejection fraction (LVEF) was assessed together with thermodilution cardiac output (CO) and high sensitivity cardiac troponin T (hs-cTnT). Neurological impairment was evaluated by neurological scores, serum neuron specific enolase (NSE), and histopathology. More than 60% of animals survived when the duration of CA was ≤13 min, compared to only 20% for a duration ≥14 min. Neuronal degeneration and neurological scores showed a trend toward a worse recovery for longer no-flow durations. No animals achieved a good neurological recovery for a no-flow ≥14 min, in comparison to a 56% for a duration ≤13 min (P = 0.043). Serum NSE levels significantly correlated with the no-flow duration (r = 0.892). Longer durations of CA were characterized by lower LVEF and CO compared to shorter durations (P flow time, the higher was the number of defibrillations delivered (P = 0.043). The defibrillations delivered significantly correlated with LVEF and plasma hs-cTnT. Longer no-flow durations caused greater postresuscitation myocardial and neurological dysfunction and reduced survival. An untreated CA of 12-13 min may be an optimal choice for a clinically relevant model.

  12. Environmental physiology

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    Summaries of research projects conducted during 1978 and 1979 are presented. Subject areas include: the effects of environmental pollutants on homeostasis of the hematopoietic system; pollutant effects on steroid metabolism; pollutant effects on pulmonary macrophages; effects of toxic gases on lung cells; the development of immunological methods for assessing lung damage at the cellular level; the response of erythropoietin concentration to various physiological changes; and the study of actinide metabolism in monkey skeletons

  13. The interaction of a flowing plasma with a dipole magnetic field: measurements and modelling of a diamagnetic cavity relevant to spacecraft protection

    International Nuclear Information System (INIS)

    Bamford, R; Bradford, J; Bingham, R; Gargate, L; Hapgood, M; Stamper, R; Gibson, K J; Thornton, A J; Silva, L O; Fonseca, R A; Norberg, C; Todd, T

    2008-01-01

    Here we describe a new experiment to test the shielding concept of a dipole-like magnetic field and plasma, surrounding a spacecraft forming a 'mini magnetosphere'. Initial laboratory experiments have been conducted to determine the effectiveness of a magnetized plasma barrier to be able to expel an impacting, low beta, supersonic flowing energetic plasma representing the solar wind. Optical and Langmuir probe data of the plasma density, the plasma flow velocity and the intensity of the dipole field clearly show the creation of a narrow transport barrier region and diamagnetic cavity virtually devoid of energetic plasma particles. This demonstrates the potential viability of being able to create a small 'hole' in a solar wind plasma, of the order of the ion Larmor orbit width, in which an inhabited spacecraft could reside in relative safety. The experimental results have been quantitatively compared with a 3D particle-in-cell 'hybrid' code simulation that uses kinetic ions and fluid electrons, showing good qualitative agreement and excellent quantitative agreement. Together the results demonstrate the pivotal role of particle kinetics in determining generic plasma transport barriers.

  14. Occupational physiology

    CERN Document Server

    Toomingas, Allan; Tornqvist, Ewa Wigaeus

    2011-01-01

    In a clear and accessible presentation, Occupational Physiology focuses on important issues in the modern working world. Exploring major public health problems-such as musculoskeletal disorders and stress-this book explains connections between work, well-being, and health based on up-to-date research in the field. It provides useful methods for risk assessment and guidelines on arranging a good working life from the perspective of the working individual, the company, and society as a whole.The book focuses on common, stressful situations in different professions. Reviewing bodily demands and r

  15. A Review of the Comparative Anatomy, Histology, Physiology and Pathology of the Nasal Cavity of Rats, Mice, Dogs and Non-human Primates. Relevance to Inhalation Toxicology and Human Health Risk Assessment.

    Science.gov (United States)

    Chamanza, R; Wright, J A

    2015-11-01

    There are many significant differences in the structural and functional anatomy of the nasal cavity of man and laboratory animals. Some of the differences may be responsible for the species-specific nasal lesions that are often observed in response to inhaled toxicants. This paper reviews the comparative anatomy, physiology and pathology of the nasal cavity of the rat, mouse, dog, monkey and man, highlighting factors that may influence the distribution of nasal lesions. Gross anatomical variations such as turbinate structure, folds or grooves on nasal walls, or presence or absence of accessory structures, may influence nasal airflow and species-specific uptake and deposition of inhaled material. In addition, interspecies variations in the morphological and biochemical composition and distribution of the nasal epithelium may affect the local tissue susceptibility and play a role in the development of species-specific nasal lesions. It is concluded that, while the nasal cavity of the monkey might be more similar to that of man, each laboratory animal species provides a model that responds in a characteristic and species-specific manner. Therefore for human risk assessment, careful consideration must be given to the anatomical differences between a given animal model and man. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Linking Species Traits to the Abiotic Template of Flowing Waters: Contrasting Eco physiologies Underlie Displacement of Zebra Mussels by Quagga Mussels in a Large River-Estuary

    Science.gov (United States)

    Casper, A. F.

    2005-05-01

    The St. Lawrence River-Estuary was the gateway of entry for dreissenids to North America and holds some of the oldest populations. The St. Lawrence also has four distinct physical-chemical water masses (a regional scale abiotic template) that both species inhabit. Despite their ecological similarities, quagga mussels are supplanting zebra mussels in much of their shared range. In order to try to better understand the changing distributions of these two species we compared glycogen, shell mass and tissue biomass in each of the water masses. This comparative physiological combined with experimental approaches (estuarine salinity experiments and reciprocal transplants) showed that while quagga mussels should dominate in most habitats, that abiotic/bioenergetic constraints in two regions (the Ottawa River plume and the freshwater-marine transition zone) might prevent them from dominating these locations. These findings are an example of how the interaction of landscape scale abiotic heterogeneity and a species-specific physiology can have strong impacts of distribution of biota large rivers.

  17. Effect of cocoa/chocolate ingestion on brachial artery flow-mediated dilation and its relevance to cardiovascular health and disease in humans.

    Science.gov (United States)

    Monahan, Kevin D

    2012-11-15

    Prospective studies indicate that high intake of dietary flavanols, such as those contained in cocoa/chocolate, are associated with reduced rates of cardiovascular-related morbidity and mortality in humans. Numerous mechanisms may underlie these associations such as favorable effects of flavanols on blood pressure, platelet aggregation, thrombosis, inflammation, and the vascular endothelium. The brachial artery flow-mediated dilation (FMD) technique has emerged as a robust method to quantify endothelial function in humans. Collectively, the preponderance of evidence indicates that FMD is a powerful surrogate measure for firm cardiovascular endpoints, such as cardiovascular-related mortality, in humans. Thus, literally thousands of studies have utilized this technique to document group differences in FMD, as well as to assess the effects of various interventions on FMD. In regards to the latter, numerous studies indicate that both acute and chronic ingestion of cocoa/chocolate increases FMD in humans. Increases in FMD after cocoa/chocolate ingestion appear to be dose-dependent such that greater increases in FMD are observed after ingestion of larger quantities. The mechanisms underlying these responses are likely diverse, however most data suggest an effect of increased nitric oxide bioavailability. Thus, positive vascular effects of cocoa/chocolate on the endothelium may underlie (i.e., be linked mechanistically to) reductions in cardiovascular risk in humans. Copyright © 2012 Elsevier Inc. All rights reserved.

  18. Classical and ablative Richtmyer-Meshkov instability and other ICF-relevant plasma flows diagnosed with monochromatic x-ray imaging

    International Nuclear Information System (INIS)

    Aglitskiy, Y; Metzler, N; Karasik, M; Velikovich, A L; Zalesak, S T; Schmitt, A J; Serlin, V; Weaver, J; Obenschain, S P; Gardner, J H

    2008-01-01

    In inertial confinement fusion (ICF) and high-energy density physics (HEDP), the most important manifestations of the hydrodynamic instabilities and other mixing processes involve lateral motion of the accelerated plasmas. In order to understand the experimental observations and to advance the numerical simulation codes to the point of predictive capability, it is critically important to accurately diagnose the motion of the dense plasma mass. The most advanced diagnostic technique recently developed for this purpose is the monochromatic x-ray imaging that combines large field of view with high contrast, high spatial resolution and large throughput, ensuring high temporal resolution at large magnification. Its application made it possible for the experimentalists to observe for the first time important hydrodynamic effects that trigger compressible turbulent mixing in laser targets, such as ablative Richtmyer-Meshkov (RM) instability, feedout, interaction of an RM-unstable interface with shock and rarefaction waves. It also helped to substantially improve the accuracy of diagnosing many other important plasma flows, ranging from laser-produced jets to electromagnetically driven wires in a Z-pinch, and to test various methods suggested for mitigation of the Rayleigh-Taylor instability. We will review the results obtained with the aid of this technique in ICF-HEDP studies at the Naval Research Laboratory and the prospects of its future applications.

  19. Physiological Acoustics

    Science.gov (United States)

    Young, Eric D.

    The analysis of physiological sound in the peripheral auditory system solves three important problems. First, sound energy impinging on the head must be captured and presented to the transduction apparatus in the ear as a suitable mechanical signal; second, this mechanical signal needs to be transduced into a neural representation that can be used by the brain; third, the resulting neural representation needs to be analyzed by central neurons to extract information useful to the animal. This chapter provides an overview of some aspects of the first two of these processes. The description is entirely focused on the mammalian auditory system, primarily on human hearing and on the hearing of a few commonly used laboratory animals (mainly rodents and carnivores). Useful summaries of non-mammalian hearing are available [1]. Because of the large size of the literature, review papers are referenced wherever possible.

  20. Quantification of green fluorescent protein by in vivo imaging, PCR, and flow cytometry: comparison of transgenic strains and relevance for fetal cell microchimerism.

    Science.gov (United States)

    Fujiki, Yutaka; Tao, Kai; Bianchi, Diana W; Giel-Moloney, Maryann; Leiter, Andrew B; Johnson, Kirby L

    2008-02-01

    Animal models are increasingly being used for the assessment of fetal cell microchimerism in maternal tissue. We wished to determine the optimal transgenic mouse strain and analytic technique to facilitate the detection of rare transgenic microchimeric fetal cells amongst a large number of maternal wild-type cells. We evaluated two strains of mice transgenic for the enhanced green fluorescent protein (EGFP): a commercially available, commonly used strain (C57BL/6-Tg(ACTB-EGFP)10sb/J) (CAG) and a newly created strain (ROSA26-EGFP) using three different techniques: in vivo and ex vivo fluorescent imaging (for whole body and dissected organs, respectively), PCR amplification of gfp, and flow cytometry (FCM). By fluorescent imaging, organs from CAG mice were 10-fold brighter than organs from ROSA26-EGFP mice (P characteristics that make it useful under specific experimental circumstances. The CAG mouse model is preferable when experiments require brighter cells, whereas ROSA26-EGFP is more appropriate when uniform or ubiquitous expression is more important than brightness. Investigators must carefully select the transgenic strain most suited to the experimental design to obtain the most consistent and reproducible data. In vivo imaging allows for phenotypic evaluation of whole animals and intact organs; however, we did not evaluate its utility for the detection of rare, fetal microchimeric cells in the maternal organs. Finally, while PCR amplification of a paternally inherited transgene does allow for the quantitative determination of rare microchimeric cells, FCM allows for both quantitative and qualitative evaluations of fetal cells at very high sensitivity in a plethora of maternal organs. (c) 2008 International Society for Analytical Cytology

  1. Comparative estimation of inevitable endogenous ileal flow of amino acids in Pekin ducks under varying dietary or physiological conditions and their significance to nutritional requirements for amino acids.

    Science.gov (United States)

    Akinde, D O

    2017-10-01

    In 2 experiments in Pekin ducks the inevitable endogenous ileal flow (IEIF) of AA was estimated at changing intake and source of crude fiber (CF) or soybean oil (SO) level. Also the roles of dry matter intake (DMI) and BW or age as well as the proportion of IEIF in the dietary requirement for AA were studied. In experiment 1 three basal CP (20, 60, or 100 g/kg) diets were formulated containing a low CF (LCF, 30 g/kg) or high (HCF, 80 g/kg) level; achieved with cellulose supplementation. All diets were similar in every other respect including having SO content of 40 g/kg. Four floor pens of eight 85-day-old ducks were randomly allocated to each diet. Similar diets were mixed in experiment 2 but corn cob meal replaced cellulose as the fiber source. A high SO (HSO) series was also formed by increasing the SO level from 40 g/kg in the basal series to 100 g/kg. Thus the LCF series was concurrently classified as low SO (LSO) series to control SO effect. Each of the eventual 9 diets were fed to 5 floor pens of ten 65-day-old ducks. Ileal AA flow was measured after a 5 day feeding period in both experiments. Linear regression was calculated between ileal flow and dietary intake of individual AA. The IEIF interpreted as the y-intercept of each linear function responded neither to elevated ingestion of each CF type nor to SO level. Age and DMI had no effect on IEIF computed in relation to BW, but wide discrepancies resulted when related to DMI. Overall IEIF of AA varied between 14.3 to 129.8 mg/kg BW d-1. These flows were established in model computations to account for 10 to 64% of the recommended intake of limiting AA. In conclusion the ileal inevitable flow is constant within the dietary/age conditions investigated. However it is modulated by feed intake and accounts for a significant portion of total amino acid requirement. © 2017 Poultry Science Association Inc.

  2. Space Physiology within an Exercise Physiology Curriculum

    Science.gov (United States)

    Carter, Jason R.; West, John B.

    2013-01-01

    Compare and contrast strategies remain common pedagogical practices within physiological education. With the support of an American Physiological Society Teaching Career Enhancement Award, we have developed a junior- or senior-level undergraduate curriculum for exercise physiology that compares and contrasts the physiological adaptations of…

  3. Assessment of β-carotene content, cell physiology and morphology of the yellow yeast Rhodotorula glutinis mutant 400A15 using flow cytometry.

    Science.gov (United States)

    Cutzu, Raffaela; Clemente, Ana; Reis, Alberto; Nobre, Beatriz; Mannazzu, Ilaria; Roseiro, José; Lopes da Silva, Teresa

    2013-08-01

    Flow cytometry was used to assess β-carotene content, cell membrane permeability, cell size and granularity in Rhodotorula glutinis mutant 400A15 grown under different oxygen transfer coefficients (k L a) and carbon to nitrogen ratios (C/N). A Doehlert distribution was used in order to select the best conditions that induced the highest carotenoids production. The highest β-carotene content (0.79 mg g(-1) DCW) at the lowest k L a and C/N (5 × 10(-3) s(-1) and 11.3 respectively). Under these conditions, the biomass concentration attained 18.60 g L(-1). The highest ratio of cells with permeabilised membranes (2.6 %), and the highest cell size and granularity were also obtained under these conditions. It was observed that C/N showed a stronger influence than the k L a on the measured cell parameters.

  4. Physiology and relevance of human adaptive thermogenesis response.

    Science.gov (United States)

    Celi, Francesco S; Le, Trang N; Ni, Bin

    2015-05-01

    In homoeothermic organisms, the preservation of core temperature represents a primal function, and its costs in terms of energy expenditure can be considerable. In modern humans, the endogenous thermoregulation mechanisms have been replaced by clothing and environmental control, and the maintenance of thermoneutrality has been successfully achieved by manipulation of the micro- and macroenvironment. The rediscovery of the presence and activity of brown adipose tissue in adult humans has renewed the interest on adaptive thermogenesis (AT) as a means to facilitate weight loss and improve carbohydrate metabolism. The aim of this review is to describe the recent advancements in the study of this function, and to assess the potential and limitations of exploiting AT for environmental/behavioral, and pharmacological interventions. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Why relevance theory is relevant for lexicography

    DEFF Research Database (Denmark)

    Bothma, Theo; Tarp, Sven

    2014-01-01

    This article starts by providing a brief summary of relevance theory in information science in relation to the function theory of lexicography, explaining the different types of relevance, viz. objective system relevance and the subjective types of relevance, i.e. topical, cognitive, situational...... that is very important for lexicography as well as for information science, viz. functional relevance. Since all lexicographic work is ultimately aimed at satisfying users’ information needs, the article then discusses why the lexicographer should take note of all these types of relevance when planning a new...... dictionary project, identifying new tasks and responsibilities of the modern lexicographer. The article furthermore discusses how relevance theory impacts on teaching dictionary culture and reference skills. By integrating insights from lexicography and information science, the article contributes to new...

  6. Physiology of bile secretion.

    Science.gov (United States)

    Esteller, Alejandro

    2008-10-07

    The formation of bile depends on the structural and functional integrity of the bile-secretory apparatus and its impairment, in different situations, results in the syndrome of cholestasis. The structural bases that permit bile secretion as well as various aspects related with its composition and flow rate in physiological conditions will first be reviewed. Canalicular bile is produced by polarized hepatocytes that hold transporters in their basolateral (sinusoidal) and apical (canalicular) plasma membrane. This review summarizes recent data on the molecular determinants of this primary bile formation. The major function of the biliary tree is modification of canalicular bile by secretory and reabsorptive processes in bile-duct epithelial cells (cholangiocytes) as bile passes through bile ducts. The mechanisms of fluid and solute transport in cholangiocytes will also be discussed. In contrast to hepatocytes where secretion is constant and poorly controlled, cholangiocyte secretion is regulated by hormones and nerves. A short section dedicated to these regulatory mechanisms of bile secretion has been included. The aim of this revision was to set the bases for other reviews in this series that will be devoted to specific issues related with biliary physiology and pathology.

  7. Deep learning relevance

    DEFF Research Database (Denmark)

    Lioma, Christina; Larsen, Birger; Petersen, Casper

    2016-01-01

    train a Recurrent Neural Network (RNN) on existing relevant information to that query. We then use the RNN to "deep learn" a single, synthetic, and we assume, relevant document for that query. We design a crowdsourcing experiment to assess how relevant the "deep learned" document is, compared...... to existing relevant documents. Users are shown a query and four wordclouds (of three existing relevant documents and our deep learned synthetic document). The synthetic document is ranked on average most relevant of all....

  8. Dynamic analysis of Lactobacillus delbrueckii subsp. bulgaricus CFL1 physiological characteristics during fermentation.

    Science.gov (United States)

    Rault, Aline; Bouix, Marielle; Béal, Catherine

    2008-12-01

    This study aimed at examining and comparing the relevance of various methods in order to discriminate different cellular states of Lactobacillus bulgaricus CFL1 and to improve knowledge on the dynamics of the cellular physiological state during growth and acidification. By using four fluorescent probes combined with multiparametric flow cytometry, membrane integrity, intracellular esterase activity, cellular vitality, membrane depolarization, and intracellular pH were quantified throughout fermentations. Results were compared and correlated with measurements of cultivability, acidification activity (Cinac system), and cellular ability to recover growth in fresh medium (Bioscreen system). The Cinac system and flow cytometry were relevant to distinguish different physiological states throughout growth. Lb. bulgaricus cells maintained their high viability, energetic state, membrane potential, and pH gradient in the late stationary phase, despite the gradual decrease of both cultivability and acidification activity. Viability and membrane integrity were maintained during acidification, at the expense of their cultivability and acidification activity. Finally, this study demonstrated that the physiological state during fermentation was strongly affected by intracellular pH and the pH gradient. The critical pHi of Lb. bulgaricus CFL1 was found to be equal to pH 5.8. Through linear relationships between dpH and cultivability and pHi and acidification activity, pHi and dpH well described the time course of metabolic activity, cultivability, and viability in a single analysis.

  9. Role of Coronary Myogenic Response in Pressure-Flow Autoregulation in Swine: A Meta-Analysis With Coronary Flow Modeling

    Science.gov (United States)

    Dick, Gregory M.; Namani, Ravi; Patel, Bhavesh; Kassab, Ghassan S.

    2018-01-01

    Myogenic responses (pressure-dependent contractions) of coronary arterioles play a role in autoregulation (relatively constant flow vs. pressure). Publications on myogenic reactivity in swine coronaries vary in caliber, analysis, and degree of responsiveness. Further, data on myogenic responses and autoregulation in swine have not been completely compiled, compared, and modeled. Thus, it has been difficult to understand these physiological phenomena. Our purpose was to: (a) analyze myogenic data with standard criteria; (b) assign results to diameter categories defined by morphometry; and (c) use our novel multiscale flow model to determine the extent to which ex vivo myogenic reactivity can explain autoregulation in vivo. When myogenic responses from the literature are an input for our model, the predicted coronary autoregulation approaches in vivo observations. More complete and appropriate data are now available to investigate the regulation of coronary blood flow in swine, a highly relevant model for human physiology and disease. PMID:29875686

  10. Role of Coronary Myogenic Response in Pressure-Flow Autoregulation in Swine: A Meta-Analysis With Coronary Flow Modeling

    Directory of Open Access Journals (Sweden)

    Gregory M. Dick

    2018-05-01

    Full Text Available Myogenic responses (pressure-dependent contractions of coronary arterioles play a role in autoregulation (relatively constant flow vs. pressure. Publications on myogenic reactivity in swine coronaries vary in caliber, analysis, and degree of responsiveness. Further, data on myogenic responses and autoregulation in swine have not been completely compiled, compared, and modeled. Thus, it has been difficult to understand these physiological phenomena. Our purpose was to: (a analyze myogenic data with standard criteria; (b assign results to diameter categories defined by morphometry; and (c use our novel multiscale flow model to determine the extent to which ex vivo myogenic reactivity can explain autoregulation in vivo. When myogenic responses from the literature are an input for our model, the predicted coronary autoregulation approaches in vivo observations. More complete and appropriate data are now available to investigate the regulation of coronary blood flow in swine, a highly relevant model for human physiology and disease.

  11. Chewing Over Physiology Integration

    Science.gov (United States)

    Abdulkader, Fernando; Azevedo-Martins, Anna Karenina; de Arcisio Miranda, Manoel; Brunaldi, Kellen

    2005-01-01

    An important challenge for both students and teachers of physiology is to integrate the differentareas in which physiological knowledge is didactically divided. In developing countries, such an issue is even more demanding, because budget restrictions often affect the physiology program with laboratory classes being the first on the list when it…

  12. Plant Physiology in Greenhouses

    NARCIS (Netherlands)

    Heuvelink, E.; Kierkels, T.

    2015-01-01

    Since 2004 Ep Heuvelink and Tijs Kierkels have been writing a continuing series of plant physiology articles for the Dutch horticultural journal Onder Glas and the international edition In Greenhouses. The book Plant Physiology in Greenhouses consists of 50 of their plant physiology articles. The

  13. Physiologic stress interventions in cardiac imaging

    International Nuclear Information System (INIS)

    Buda, A.J.

    1985-01-01

    Physiologic stress interventions are designed to assess the reserve capability of coronary flow and myocardial function. In the normal individual, a sufficiently intense physiologic stress may increase coronary flow and cardiac output by 500% to 600%. However, in patients with cardiac disease, these reserve responses may be absent, or considerably blunted. Thus, physiologic stress testing has proved extremely helpful in detecting cardiac abnormalities when resting cardiac function appears normal. Although dynamic exercise remains the standard approach to physiologic stress testing, a number of other interventions have been used, including: (1) isometric exercise, (2) atrial pacing, (3) cold pressor testing, (4) postextrasystolic potentiation, (5) volume loading, and (6) negative intrathoracic pressure. Each of these may be considered an alternative physiologic intervention whenever dynamic exercise is not feasible. These alternative approaches are important since, in our experience, 20% to 30% of subjects are unable to perform dynamic exercise, or exercise inadequately to produce a sufficiently intense cardiac stress. This chapter reviews physiologic considerations, indications, contraindications, protocols, and results of these physiologic stress interventions when used in combination with cardiac radionuclide procedures

  14. Doppler radar physiological sensing

    CERN Document Server

    Lubecke, Victor M; Droitcour, Amy D; Park, Byung-Kwon; Singh, Aditya

    2016-01-01

    Presents a comprehensive description of the theory and practical implementation of Doppler radar-based physiological monitoring. This book includes an overview of current physiological monitoring techniques and explains the fundamental technology used in remote non-contact monitoring methods. Basic radio wave propagation and radar principles are introduced along with the fundamentals of physiological motion and measurement. Specific design and implementation considerations for physiological monitoring radar systems are then discussed in detail. The authors address current research and commercial development of Doppler radar based physiological monitoring for healthcare and other applications.

  15. The impact of coronary chronic total occlusion percutaneous coronary intervention upon donor vessel fractional flow reserve and instantaneous wave-free ratio: Implications for physiology-guided PCI in patients with CTO.

    Science.gov (United States)

    Mohdnazri, Shah R; Karamasis, Grigoris V; Al-Janabi, Firas; Cook, Christopher M; Hampton-Till, James; Zhang, Jufen; Al-Lamee, Rasha; Dungu, Jason N; Gedela, Swamy; Tang, Kare H; Kelly, Paul A; Davies, Justin E; Davies, John R; Keeble, Thomas R

    2018-03-22

    To investigate the immediate and short term impact of right coronary artery (RCA) chronic total coronary occlusion (CTO) percutaneous coronary intervention (PCI) upon collateral donor vessel fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR). CTO PCI influences collateral donor vessel physiology, making the indication and/or timing of donor vessel revascularization difficult to determine. In patients with RCA CTO, FFR, iFR, and collateral function index (FFR coll ) were measured in LAD and LCx pre-CTO PCI, immediately post and at 4 month follow-up. 34 patients underwent successful PCI. In the predominant donor vessel immediately post PCI, FFR, and FFR coll did not change (0.76 ± 0.12 to 0.75 ± 0.13, P = 0.267 and 0.31 ± 0.10 vs. 0.34 ± 0.11, P = 0.078), but iFR increased significantly (0.86 ± 0.10 to 0.88 ± 0.10, P = 0.012). At follow-up, there was a significant increase in predominant donor FFR and iFR (0.76 ± 0.12 to 0.79 ± 0.11, P = 0.047 and 0.86 ± 0.10 to 0.90 ± 0.07, P = 0.003), accompanied by a significant reduction in FFR coll (0.31 ± 0.10 to 0.18 ± 0.07 P PCI in the case of iFR and at 4-month follow-up for FFR and iFR compared to pre-PCI with a concomitant reduction in collateral function. © 2018 Wiley Periodicals, Inc.

  16. Adaptation of endothelial cells to physiologically-modeled, variable shear stress.

    Directory of Open Access Journals (Sweden)

    Joseph S Uzarski

    Full Text Available Endothelial cell (EC function is mediated by variable hemodynamic shear stress patterns at the vascular wall, where complex shear stress profiles directly correlate with blood flow conditions that vary temporally based on metabolic demand. The interactions of these more complex and variable shear fields with EC have not been represented in hemodynamic flow models. We hypothesized that EC exposed to pulsatile shear stress that changes in magnitude and duration, modeled directly from real-time physiological variations in heart rate, would elicit phenotypic changes as relevant to their critical roles in thrombosis, hemostasis, and inflammation. Here we designed a physiological flow (PF model based on short-term temporal changes in blood flow observed in vivo and compared it to static culture and steady flow (SF at a fixed pulse frequency of 1.3 Hz. Results show significant changes in gene regulation as a function of temporally variable flow, indicating a reduced wound phenotype more representative of quiescence. EC cultured under PF exhibited significantly higher endothelial nitric oxide synthase (eNOS activity (PF: 176.0±11.9 nmol/10(5 EC; SF: 115.0±12.5 nmol/10(5 EC, p = 0.002 and lower TNF-a-induced HL-60 leukocyte adhesion (PF: 37±6 HL-60 cells/mm(2; SF: 111±18 HL-60/mm(2, p = 0.003 than cells cultured under SF which is consistent with a more quiescent anti-inflammatory and anti-thrombotic phenotype. In vitro models have become increasingly adept at mimicking natural physiology and in doing so have clarified the importance of both chemical and physical cues that drive cell function. These data illustrate that the variability in metabolic demand and subsequent changes in perfusion resulting in constantly variable shear stress plays a key role in EC function that has not previously been described.

  17. Neuromodulators: available agents, physiology, and anatomy.

    Science.gov (United States)

    Nettar, Kartik; Maas, Corey

    2011-12-01

    Neuromodulators have risen to the forefront of aesthetic medicine. By reversibly relaxing target muscles, neuromodulators exhibit their effect by softening hyperfunctional lines. An understanding of their physiology, relevant facial anatomy, and current agents is imperative for a successful aesthetic practice. © Thieme Medical Publishers.

  18. Making Deferred Taxes Relevant

    NARCIS (Netherlands)

    Brouwer, Arjan; Naarding, Ewout

    2018-01-01

    We analyse the conceptual problems in current accounting for deferred taxes and provide solutions derived from the literature in order to make International Financial Reporting Standards (IFRS) deferred tax numbers value-relevant. In our view, the empirical results concerning the value relevance of

  19. Parsimonious relevance models

    NARCIS (Netherlands)

    Meij, E.; Weerkamp, W.; Balog, K.; de Rijke, M.; Myang, S.-H.; Oard, D.W.; Sebastiani, F.; Chua, T.-S.; Leong, M.-K.

    2008-01-01

    We describe a method for applying parsimonious language models to re-estimate the term probabilities assigned by relevance models. We apply our method to six topic sets from test collections in five different genres. Our parsimonious relevance models (i) improve retrieval effectiveness in terms of

  20. Physiology of in vitro culture

    Directory of Open Access Journals (Sweden)

    Maria Jesús Cañal

    2001-01-01

    Full Text Available The culture procedures described up to the eighties, did not made any mention to the environmental control of in vitro plant development. However, growth rate, development and many of the physiologic-morphologic features of the in vitro grown plants are influenced by the culture vessel. The increasing knowledge about the environmental control of culture vessels under sterile conditions, is helping to change micorpropagation procedures. The in vitro environment with lower rate ventilation, brings about low flow rates of matter and energy, with minimum variations of temperature, high relative humidity and large daily changes of the concentration of CO2 inside the culture vessel. The type of culture vessel (size, shape, fabric and closing system can influence the evolution of the atmosphere along the time of culture. Although submitted to different stresses factors plant can be grown in vitro, but plants can be faulty in their anatomy, morphology and physiology. As a consequence, these plants shown a phenotype unable to survive to ex vitro conditions. Different strategies can be used to control the atmosphere along the different phases of micropropagation, in heterotrophic, mixotrophic or autotrophic cultures. The election of the best strategy will be based on different factors as species, number of transplantes required, or quality-price relationship. enviromental control, tissue culture, micropropagation Keywords: in vitro enviromental, characteristic physiology,

  1. Advances in physiological computing

    CERN Document Server

    Fairclough, Stephen H

    2014-01-01

    This edited collection will provide an overview of the field of physiological computing, i.e. the use of physiological signals as input for computer control. It will cover a breadth of current research, from brain-computer interfaces to telemedicine.

  2. Bone biology and physiology: Part I. The fundamentals.

    Science.gov (United States)

    Buck, Donald W; Dumanian, Gregory A

    2012-06-01

    The principles of bone biology and physiology permeate all subspecialty practices in plastic and reconstructive surgery from hand surgery to aesthetic surgery. Despite its importance in our practices, the biology of bone healing and bone physiology rarely surfaces within textbooks, literature reviews, or residency curricula. In this article, the authors present the first of a two-part series reviewing the important concepts of bone biology and bone physiology relevant to plastic surgery in an effort to ameliorate this educational gap.

  3. Neonatal Hemodynamics: From Developmental Physiology to Comprehensive Monitoring

    Directory of Open Access Journals (Sweden)

    Sabine L. Vrancken

    2018-04-01

    Full Text Available Maintenance of neonatal circulatory homeostasis is a real challenge, due to the complex physiology during postnatal transition and the inherent immaturity of the cardiovascular system and other relevant organs. It is known that abnormal cardiovascular function during the neonatal period is associated with increased risk of severe morbidity and mortality. Understanding the functional and structural characteristics of the neonatal circulation is, therefore, essential, as therapeutic hemodynamic interventions should be based on the assumed underlying (pathophysiology. The clinical assessment of systemic blood flow (SBF by indirect parameters, such as blood pressure, capillary refill time, heart rate, urine output, and central-peripheral temperature difference is inaccurate. As blood pressure is no surrogate for SBF, information on cardiac output and systemic vascular resistance should be obtained in combination with an evaluation of end organ perfusion. Accurate and reliable hemodynamic monitoring systems are required to detect inadequate tissue perfusion and oxygenation at an early stage before this result in irreversible damage. Also, the hemodynamic response to the initiated treatment should be re-evaluated regularly as changes in cardiovascular function can occur quickly. New insights in the understanding of neonatal cardiovascular physiology are reviewed and several methods for current and future neonatal hemodynamic monitoring are discussed.

  4. Culturally Relevant Cyberbullying Prevention

    OpenAIRE

    Phillips, Gregory John

    2017-01-01

    In this action research study, I, along with a student intervention committee of 14 members, developed a cyberbullying intervention for a large urban high school on the west coast. This high school contained a predominantly African American student population. I aimed to discover culturally relevant cyberbullying prevention strategies for African American students. The intervention committee selected video safety messages featuring African American actors as the most culturally relevant cyber...

  5. Laminar flow resistance in short microtubes

    Energy Technology Data Exchange (ETDEWEB)

    Phares, D.J. [Texas A and M University, College Station, TX (United States). Dept. of Mechanical Engineering; Smedley, G.T.; Zhou, J. [Glaukos Corp., Laguna Hills, CA (United States). Dept. of Research and Development

    2005-06-01

    We have measured the pressure drop for the flow of liquid through a series of short microtubes ranging from 80 to 150 {mu}m in diameter with aspect ratios between L/D = 2 and L/D = 5. These dimensions were selected to resemble lumens of implantable microstents that are under consideration for the treatment of glaucoma. For physiologically relevant pressure drops and flow rates, we have determined that a fully-developed laminar pipe flow may be assumed throughout the microtube when (L/D) > 0.20Re, where Re is the Reynolds number based on the diameter, D, and L is the length of the tube. We have examined flow rates between 0.1 and 10 {mu}L/s, corresponding to Reynolds numbers between 1 and 150. For smooth microtubes, no difference from macroscopic flow is observed for the tube sizes considered. However, flow resistance is found to be sensitive to the relative surface roughness of the tube walls. (author)

  6. Reproduction, physiology and biochemistry

    Science.gov (United States)

    This chapter summarizes fundamental knowledge and recent discoveries about the reproduction, physiology and biochemistry of plant-parasitic nematodes. Various types of reproduction are reviewed, including sexual reproduction and mitotic and meiotic parthenogenesis. Although much is known about the p...

  7. Endogenous Pyrogen Physiology.

    Science.gov (United States)

    Beisel, William R.

    1980-01-01

    Discusses the physiology of endogenous pyrogen (EP), the fever-producing factor of cellular origin. Included are: its hormone-like role, its molecular nature, bioassay procedures, cellular production and mechanisms of EP action. (SA)

  8. Aspects on the Physiological and Biochemical Foundations of Neurocritical Care

    Directory of Open Access Journals (Sweden)

    Carl-Henrik Nordström

    2017-06-01

    Full Text Available Neurocritical care (NCC is a branch of intensive care medicine characterized by specific physiological and biochemical monitoring techniques necessary for identifying cerebral adverse events and for evaluating specific therapies. Information is primarily obtained from physiological variables related to intracranial pressure (ICP and cerebral blood flow (CBF and from physiological and biochemical variables related to cerebral energy metabolism. Non-surgical therapies developed for treating increased ICP are based on knowledge regarding transport of water across the intact and injured blood–brain barrier (BBB and the regulation of CBF. Brain volume is strictly controlled as the BBB permeability to crystalloids is very low restricting net transport of water across the capillary wall. Cerebral pressure autoregulation prevents changes in intracranial blood volume and intracapillary hydrostatic pressure at variations in arterial blood pressure. Information regarding cerebral oxidative metabolism is obtained from measurements of brain tissue oxygen tension (PbtO2 and biochemical data obtained from intracerebral microdialysis. As interstitial lactate/pyruvate (LP ratio instantaneously reflects shifts in intracellular cytoplasmatic redox state, it is an important indicator of compromised cerebral oxidative metabolism. The combined information obtained from PbtO2, LP ratio, and the pattern of biochemical variables reveals whether impaired oxidative metabolism is due to insufficient perfusion (ischemia or mitochondrial dysfunction. Intracerebral microdialysis and PbtO2 give information from a very small volume of tissue. Accordingly, clinical interpretation of the data must be based on information of the probe location in relation to focal brain damage. Attempts to evaluate global cerebral energy state from microdialysis of intraventricular fluid and from the LP ratio of the draining venous blood have recently been presented. To be of clinical relevance

  9. Biophysics and cell physiology

    International Nuclear Information System (INIS)

    Mazur, P.

    1975-01-01

    Progress is reported on research activities in the fields of physiology and low-temperature biology of mammalian embryos; effects of sub-zero temperatures on eggs and embryos of sea urchins; survival of frozen-thawed human red cells; effects of radiation on physiology of Escherichia coli; transfer of triplet electronic energy in dinucleotides; effects of x radiation on DNA degradation; energy deposition by neutrons; photosynthesis; excision repair of uv-induced pyrimidine dimers in DNA of plant cells

  10. Physiology of Ramadan fasting

    OpenAIRE

    Shokoufeh Bonakdaran

    2016-01-01

    Considering the emphasis of Islam on the importance of fasting, Muslims attempt to fast from dawn until sunset during the holy month of Ramadan. Fasting is associated with several benefits for normal and healthy individuals. However, it could pose high risks to the health of diabetic patients due to certain physiological changes. This study aimed to compare the physiological changes associated with fasting in healthy individuals and diabetic patients during Ramadan. Furthermore, we reviewed t...

  11. Assessment of the adequacy of bronchial stenting by flow-volume loops

    Energy Technology Data Exchange (ETDEWEB)

    McLaren, Clare A.; Roebuck, Derek J. [Great Ormond Street Hospital for Children, Department of Radiology, London (United Kingdom); Pigott, Nick; Elliott, Martin J. [Great Ormond Street Hospital for Children, Cardiothoracic Unit, London (United Kingdom); Dunne, Catherine [Great Ormond Street Hospital for Children, Department of Physiotherapy, London (United Kingdom)

    2006-08-15

    Airway compression is a common problem in children with certain forms of congenital heart disease. Although various surgical approaches are available to overcome this form of airway obstruction, internal stenting is necessary in a minority of patients. It can be difficult to assess the success of stenting at the time of the procedure, and the interval to successful extubation is usually used as an outcome measure. Measurement of relevant parameters of respiratory physiology with flow-volume and volume-pressure loops permits immediate quantitative assessment of the adequacy of stenting. A 3-month-old infant who underwent bronchial stenting and physiological assessment at the time of the procedure is described. (orig.)

  12. Assessment of the adequacy of bronchial stenting by flow-volume loops

    International Nuclear Information System (INIS)

    McLaren, Clare A.; Roebuck, Derek J.; Pigott, Nick; Elliott, Martin J.; Dunne, Catherine

    2006-01-01

    Airway compression is a common problem in children with certain forms of congenital heart disease. Although various surgical approaches are available to overcome this form of airway obstruction, internal stenting is necessary in a minority of patients. It can be difficult to assess the success of stenting at the time of the procedure, and the interval to successful extubation is usually used as an outcome measure. Measurement of relevant parameters of respiratory physiology with flow-volume and volume-pressure loops permits immediate quantitative assessment of the adequacy of stenting. A 3-month-old infant who underwent bronchial stenting and physiological assessment at the time of the procedure is described. (orig.)

  13. The Limits to Relevance

    Science.gov (United States)

    Averill, M.; Briggle, A.

    2006-12-01

    Science policy and knowledge production lately have taken a pragmatic turn. Funding agencies increasingly are requiring scientists to explain the relevance of their work to society. This stems in part from mounting critiques of the "linear model" of knowledge production in which scientists operating according to their own interests or disciplinary standards are presumed to automatically produce knowledge that is of relevance outside of their narrow communities. Many contend that funded scientific research should be linked more directly to societal goals, which implies a shift in the kind of research that will be funded. While both authors support the concept of useful science, we question the exact meaning of "relevance" and the wisdom of allowing it to control research agendas. We hope to contribute to the conversation by thinking more critically about the meaning and limits of the term "relevance" and the trade-offs implicit in a narrow utilitarian approach. The paper will consider which interests tend to be privileged by an emphasis on relevance and address issues such as whose goals ought to be pursued and why, and who gets to decide. We will consider how relevance, narrowly construed, may actually limit the ultimate utility of scientific research. The paper also will reflect on the worthiness of research goals themselves and their relationship to a broader view of what it means to be human and to live in society. Just as there is more to being human than the pragmatic demands of daily life, there is more at issue with knowledge production than finding the most efficient ways to satisfy consumer preferences or fix near-term policy problems. We will conclude by calling for a balanced approach to funding research that addresses society's most pressing needs but also supports innovative research with less immediately apparent application.

  14. Relevant Subspace Clustering

    DEFF Research Database (Denmark)

    Müller, Emmanuel; Assent, Ira; Günnemann, Stephan

    2009-01-01

    Subspace clustering aims at detecting clusters in any subspace projection of a high dimensional space. As the number of possible subspace projections is exponential in the number of dimensions, the result is often tremendously large. Recent approaches fail to reduce results to relevant subspace...... clusters. Their results are typically highly redundant, i.e. many clusters are detected multiple times in several projections. In this work, we propose a novel model for relevant subspace clustering (RESCU). We present a global optimization which detects the most interesting non-redundant subspace clusters...... achieves top clustering quality while competing approaches show greatly varying performance....

  15. Knowledge Retention of Exercise Physiology Content between Athletes and Nonathletes

    Science.gov (United States)

    Clark, Brian; Webster, Collin; Druger, Marvin

    2006-01-01

    Based on the idea that learning is linked to personal relevance, this study examined knowledge retention of exercise physiology content between college athletes and nonathletes. No differences were observed between the groups. These findings have implications on understanding the relationship between personal relevance and memory. (Contains 1…

  16. Cerebral autoregulation control of blood flow in the brain

    CERN Document Server

    Payne, Stephen

    2016-01-01

    This Brief provides a comprehensive introduction to the control of blood flow in the brain. Beginning with the basic physiology of autoregulation, the author goes on to discuss measurement techniques, mathematical models, methods of analysis, and relevant clinical conditions, all within this single volume. The author draws together this disparate field, and lays the groundwork for future research directions. The text gives an up-to-date review of the state of the art in cerebral autoregulation, which is particularly relevant as cerebral autoregulation moves from the laboratory to the bedside. Cerebral Autoregulation will be useful to researchers in the physical sciences such as mathematical biology, medical physics, and biomedical engineering whose work is concerned with the brain. Researchers in the medical sciences and clinicians dealing with the brain and blood flow, as well as industry professionals developing techniques such as ultrasound, MRI, and CT will also find this Brief of interest.

  17. Is Information Still Relevant?

    Science.gov (United States)

    Ma, Lia

    2013-01-01

    Introduction: The term "information" in information science does not share the characteristics of those of a nomenclature: it does not bear a generally accepted definition and it does not serve as the bases and assumptions for research studies. As the data deluge has arrived, is the concept of information still relevant for information…

  18. Magnesium degradation under physiological conditions - Best practice.

    Science.gov (United States)

    Gonzalez, Jorge; Hou, Rui Qing; Nidadavolu, Eshwara P S; Willumeit-Römer, Regine; Feyerabend, Frank

    2018-06-01

    This review focusses on the application of physiological conditions for the mechanistic understanding of magnesium degradation. Despite the undisputed relevance of simplified laboratory setups for alloy screening purposes, realistic and predictive in vitro setups are needed. Due to the complexity of these systems, the review gives an overview about technical measures, defines some caveats and can be used as a guideline for the establishment of harmonized laboratory approaches.

  19. Causes of Low and High Citation Potentials in Science: Citation Analysis of Biochemistry and Plant Physiology Journals.

    Science.gov (United States)

    Marton, Janos

    1983-01-01

    Citation data of 16 biochemistry and plant physiology journals show that reasons for lower citation potentials of plant physiology articles are: (1) readership is narrower for plant physiology journals; (2) plant physiologists can cite fewer thematically relevant new articles; and (3) plant physiology research fields are more isolated. References…

  20. Plant Physiology and Development

    DEFF Research Database (Denmark)

    Taiz, Lincoln; Zeiger, Eduardo; Møller, Ian Max

    Throughout its twenty-two year history, the authors of Plant Physiology have continually updated the book to incorporate the latest advances in plant biology and implement pedagogical improvements requested by adopters. This has made Plant Physiology the most authoritative, comprehensive......, and widely used upper-division plant biology textbook. In the Sixth Edition, the Growth and Development section (Unit III) has been reorganized and expanded to present the complete life cycle of seed plants from germination to senescence. In recognition of this enhancement, the text has been renamed Plant...... Physiology and Development. As before, Unit III begins with updated chapters on Cell Walls and Signals and Signal Transduction. The latter chapter has been expanded to include a discussion of major signaling molecules, such as calcium ions and plant hormones. A new, unified chapter entitled Signals from...

  1. Clinical Relevance of Adipokines

    Directory of Open Access Journals (Sweden)

    Matthias Blüher

    2012-10-01

    Full Text Available The incidence of obesity has increased dramatically during recent decades. Obesity increases the risk for metabolic and cardiovascular diseases and may therefore contribute to premature death. With increasing fat mass, secretion of adipose tissue derived bioactive molecules (adipokines changes towards a pro-inflammatory, diabetogenic and atherogenic pattern. Adipokines are involved in the regulation of appetite and satiety, energy expenditure, activity, endothelial function, hemostasis, blood pressure, insulin sensitivity, energy metabolism in insulin sensitive tissues, adipogenesis, fat distribution and insulin secretion in pancreatic β-cells. Therefore, adipokines are clinically relevant as biomarkers for fat distribution, adipose tissue function, liver fat content, insulin sensitivity, chronic inflammation and have the potential for future pharmacological treatment strategies for obesity and its related diseases. This review focuses on the clinical relevance of selected adipokines as markers or predictors of obesity related diseases and as potential therapeutic tools or targets in metabolic and cardiovascular diseases.

  2. Information Needs/Relevance

    OpenAIRE

    Wildemuth, Barbara M.

    2009-01-01

    A user's interaction with a DL is often initiated as the result of the user experiencing an information need of some kind. Aspects of that experience and how it might affect the user's interactions with the DL are discussed in this module. In addition, users continuously make decisions about and evaluations of the materials retrieved from a DL, relative to their information needs. Relevance judgments, and their relationship to the user's information needs, are discussed in this module. Draft

  3. Tissue physiology and the response to heat

    DEFF Research Database (Denmark)

    Horsman, Michael Robert

    2006-01-01

    physiological effects should occur in normal tissues, such combination therapies must be carefully applied. Heating tumours to higher temperatures typically causes a transient increase in perfusion during heating, followed by vascular collapse which if sufficient will increase tumour necrosis. The speed...... and degree of vascular collapse is dependent on heating time, temperature and tumour model used. Such vascular collapse generally occurs at temperatures that cause a substantial blood flow increase in certain normal tissues, thus preferential anti-tumour effects can be achieved. The tumour vascular supply...... can also be exploited to improve the response to heat. Decreasing blood flow, using transient physiological modifiers or longer acting vascular disrupting agents prior to the initiation of heating, can both increase the accumulation of physical heat in the tumour, as well as increase heat sensitivity...

  4. Regulation of tumor invasion by interstitial fluid flow

    International Nuclear Information System (INIS)

    Shieh, Adrian C; Swartz, Melody A

    2011-01-01

    The importance of the tumor microenvironment in cancer progression is undisputed, yet the significance of biophysical forces in the microenvironment remains poorly understood. Interstitial fluid flow is a nearly ubiquitous and physiologically relevant biophysical force that is elevated in tumors because of tumor-associated angiogenesis and lymphangiogenesis, as well as changes in the tumor stroma. Not only does it apply physical forces to cells directly, but interstitial flow also creates gradients of soluble signals in the tumor microenvironment, thus influencing cell behavior and modulating cell–cell interactions. In this paper, we highlight our current understanding of interstitial fluid flow in the context of the tumor, focusing on the physical changes that lead to elevated interstitial flow, how cells sense flow and how they respond to changes in interstitial flow. In particular, we emphasize that interstitial flow can directly promote tumor cell invasion through a mechanism known as autologous chemotaxis, and indirectly support tumor invasion via both biophysical and biochemical cues generated by stromal cells. Thus, interstitial fluid flow demonstrates how important biophysical factors are in cancer, both by modulating cell behavior and coupling biophysical and biochemical signals

  5. Nigerian Journal of Physiological Sciences

    African Journals Online (AJOL)

    Nigerian Journal of Physiological Sciences (Niger. J. Physiol. Sci.) is a biannual publication of the Physiological Society of Nigeria. It covers diverse areas of research in physiological sciences, publishing reviews in current research areas and original laboratory and clinical research in physiological sciences. Other websites ...

  6. Simulated Exercise Physiology Laboratories.

    Science.gov (United States)

    Morrow, James R., Jr.; Pivarnik, James M.

    This book consists of a lab manual and computer disks for either Apple or IBM hardware. The lab manual serves as "tour guide" for the learner going through the various lab experiences. The manual contains definitions, proper terminology, and other basic information about physiological principles. It is organized so a step-by-step procedure may be…

  7. Physiology Flies with Time.

    Science.gov (United States)

    Sehgal, Amita

    2017-11-30

    The 2017 Nobel Prize in Medicine or Physiology has been awarded to Jeffrey Hall, Michael Rosbash, and Michael Young for elucidating molecular mechanisms of the circadian clock. From studies beginning in fruit flies, we now know that circadian regulation pervades most biological processes and has strong ties to human health and disease. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Personalized physiological medicine

    NARCIS (Netherlands)

    Ince, Can

    2017-01-01

    This paper introduces the concept of personalized physiological medicine that is specifically directed at the needs of the critically ill patient. This differs from the conventional view of personalized medicine, characterized by biomarkers and gene profiling, instead focusing on time-variant

  9. Physiological responses to hypothermia.

    Science.gov (United States)

    Wood, Thomas; Thoresen, Marianne

    2015-04-01

    Therapeutic hypothermia is the only treatment currently recommended for moderate or severe encephalopathy of hypoxic‒ischaemic origin in term neonates. Though the effects of hypothermia on human physiology have been explored for many decades, much of the data comes from animal or adult studies; the latter originally after accidental hypothermia, followed by application of controlled hypothermia after cardiac arrest or trauma, or during cardiopulmonary bypass. Though this work is informative, the effects of hypothermia on neonatal physiology after perinatal asphyxia must be considered in the context of a prolonged hypoxic insult that has already induced a number of significant physiological sequelae. This article reviews the effects of therapeutic hypothermia on respiratory, cardiovascular, and metabolic parameters, including glycaemic control and feeding requirements. The potential pitfalls of blood‒gas analysis and overtreatment of physiological changes in cardiovascular parameters are also discussed. Finally, the effects of hypothermia on drug metabolism are covered, focusing on how the pharmacokinetics, pharmacodynamics, and dosing requirements of drugs frequently used in neonatal intensive care may change during therapeutic hypothermia. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. The Face of Physiology

    Directory of Open Access Journals (Sweden)

    Paul White

    2008-10-01

    Full Text Available This article explores the relationship between the physiology of the emotions and the display of character in Victorian Britain. Charles Bell and others had begun to link certain physiological functions, such as respiration, with the expression of feelings such as fear, regarding the heart and other internal organs as instruments by which the emotions were made visible. But a purely functional account of the emotions, which emerged through the development of reflex physiology during the second half of the century, would dramatically alter the nature of feelings and the means of observing them. At the same time, instinctual or acquired sympathy, which had long underpinned the accurate reading of expressions, became a problem to be surmounted by new 'objectively'. Graphic recording instruments measuring a variety of physiological functions and used with increasing frequency in clinical diagnostics became of fundamental importance for tracing the movement of feelings during the period prior to the development of cinematography. They remained, in the form of devices such as the polygraph, a crucial and controversial means of measuring affective states, beneath the potentially deceptive surface of the body.

  11. Physiomodel - an integrative physiology in Modelica.

    Science.gov (United States)

    Matejak, Marek; Kofranek, Jiri

    2015-08-01

    Physiomodel (http://www.physiomodel.org) is our reimplementation and extension of an integrative physiological model called HumMod 1.6 (http://www.hummod.org) using our Physiolibrary (http://www.physiolibrary.org). The computer language Modelica is well-suited to exactly formalize integrative physiology. Modelica is an equation-based, and object-oriented language for hybrid ordinary differential equations (http:// www.modelica.org). Almost every physiological term can be defined as a class in this language and can be instantiated as many times as it occurs in the body. Each class has a graphical icon for use in diagrams. These diagrams are self-describing; the Modelica code generated from them is the full representation of the underlying mathematical model. Special Modelica constructs of physical connectors from Physiolibrary allow us to create diagrams that are analogies of electrical circuits with Kirchhoff's laws. As electric currents and electric potentials are connected in electrical domain, so are molar flows and concentrations in the chemical domain; volumetric flows and pressures in the hydraulic domain; flows of heat energy and temperatures in the thermal domain; and changes and amounts of members in the population domain.

  12. Avian reproductive physiology

    Science.gov (United States)

    Gee, G.F.; Gibbons, Edward F.; Durrant, Barbara S.; Demarest, Jack

    1995-01-01

    Knowledge of the many physiological factors associated with egg production , fertility, incubation, and brooding in nondomestic birds is limited. Science knows even less about reproduction in most of the 238 endangered or threatened birds. This discussion uses studies of nondomestic and, when necessary, domestic birds to describe physiological control of reproduction. Studies of the few nondomestic avian species show large variation in physiological control of reproduction. Aviculturists, in order to successfully propagate an endangered bird, must understand the bird's reproductive peculiarities. First, investigators can do studies with carefully chosen surrogate species, but eventually they need to confirm the results in the target endangered bird. Studies of reproduction in nondomestic birds increased in the last decade. Still, scientists need to do more comparative studies to understand the mechanisms that control reproduction in birds. New technologies are making it possible to study reproductive physiology of nondomestic species in less limiting ways. These technologies include telemetry to collect information without inducing stress on captives (Howey et al., 1987; Klugman, 1987), new tests for most of the humoral factors associated with reproduction, and the skill to collect small samples and manipulate birds without disrupting the physiological mechanisms (Bercovitz et al., 1985). Managers are using knowledge from these studies to improve propagation in zoological parks, private and public propagation facilities, and research institutions. Researchers need to study the control of ovulation, egg formation, and oviposition in the species of nondomestic birds that lay very few eggs in a season, hold eggs in the oviduct for longer intervals, or differ in other ways from the more thoroughly studied domestic birds. Other techniques that would enhance propagation for nondomestlc birds include tissue culture of cloned embryonic cells, cryopreservation of embryos

  13. [Relevant public health enteropathogens].

    Science.gov (United States)

    Riveros, Maribel; Ochoa, Theresa J

    2015-01-01

    Diarrhea remains the third leading cause of death in children under five years, despite recent advances in the management and prevention of this disease. It is caused by multiple pathogens, however, the prevalence of each varies by age group, geographical area and the scenario where cases (community vs hospital) are recorded. The most relevant pathogens in public health are those associated with the highest burden of disease, severity, complications and mortality. In our country, norovirus, Campylobacter and diarrheagenic E. coli are the most prevalent pathogens at the community level in children. In this paper we review the local epidemiology and potential areas of development in five selected pathogens: rotavirus, norovirus, Shiga toxin-producing E. coli (STEC), Shigella and Salmonella. Of these, rotavirus is the most important in the pediatric population and the main agent responsible for child mortality from diarrhea. The introduction of rotavirus vaccination in Peru will have a significant impact on disease burden and mortality from diarrhea. However, surveillance studies are needed to determine the impact of vaccination and changes in the epidemiology of diarrhea in Peru following the introduction of new vaccines, as well as antibiotic resistance surveillance of clinical relevant bacteria.

  14. Renal phosphate handling: Physiology

    Directory of Open Access Journals (Sweden)

    Narayan Prasad

    2013-01-01

    Full Text Available Phosphorus is a common anion. It plays an important role in energy generation. Renal phosphate handling is regulated by three organs parathyroid, kidney and bone through feedback loops. These counter regulatory loops also regulate intestinal absorption and thus maintain serum phosphorus concentration in physiologic range. The parathyroid hormone, vitamin D, Fibrogenic growth factor 23 (FGF23 and klotho coreceptor are the key regulators of phosphorus balance in body.

  15. Other relevant biological papers

    International Nuclear Information System (INIS)

    Shimizu, M.

    1989-01-01

    A considerable number of CRESP-relevant papers concerning deep-sea biology and radioecology have been published. It is the purpose of this study to call attention to them. They fall into three general categories. The first is papers of general interest. They are mentioned only briefly, and include text references to the global bibliography at the end of the volume. The second are papers that are not only mentioned and referenced, but for various reasons are described in abstract form. The last is a list of papers compiled by H.S.J. Roe specifically for this volume. They are listed in bibliographic form, and are also included in the global bibliography at the end of the volume

  16. Circadian physiology of metabolism.

    Science.gov (United States)

    Panda, Satchidananda

    2016-11-25

    A majority of mammalian genes exhibit daily fluctuations in expression levels, making circadian expression rhythms the largest known regulatory network in normal physiology. Cell-autonomous circadian clocks interact with daily light-dark and feeding-fasting cycles to generate approximately 24-hour oscillations in the function of thousands of genes. Circadian expression of secreted molecules and signaling components transmits timing information between cells and tissues. Such intra- and intercellular daily rhythms optimize physiology both by managing energy use and by temporally segregating incompatible processes. Experimental animal models and epidemiological data indicate that chronic circadian rhythm disruption increases the risk of metabolic diseases. Conversely, time-restricted feeding, which imposes daily cycles of feeding and fasting without caloric reduction, sustains robust diurnal rhythms and can alleviate metabolic diseases. These findings highlight an integrative role of circadian rhythms in physiology and offer a new perspective for treating chronic diseases in which metabolic disruption is a hallmark. Copyright © 2016, American Association for the Advancement of Science.

  17. Applied physiology of triathlon.

    Science.gov (United States)

    O'Toole, M L; Douglas, P S

    1995-04-01

    The triathlon is a 3-event endurance sport in which athletes compete sequentially in swimming, cycling and running. The primary determinant of success is the ability to sustain a high rate of energy expenditure for prolonged periods of time. Exercise training-induced physiological adaptations in virtually all systems of the body allow the athlete to accomplish this. Aerobic capacity (measured as maximal oxygen uptake, VO2max), economy of motion (submaximal VO2) and fractional utilisation of maximal capacity (%VO2max) reflect the integrated responses of these physiological adaptations. Numerous studies have reported relatively high mean VO2max values for various groups of triathletes that are comparable to those reported for athletes in single-event endurance sports and clearly above those reported for untrained individuals. In shorter distance triathlons and in studies using recreational (rather than elite) triathletes, VO2max is related to performance in the corresponding event of the triathlon (e.g. tethered swimming VO2max with swim time). In longer events and with more elite triathletes, VO2max correlates less well with performance. The physiological adaptations that correspond to and facilitate improved VO2max occur centrally in the cardiovascular system, centred on increased maximal cardiac output, and peripherally in the metabolic systems, centred around increased arterio-venous O2 (a-v O2) difference. While a high VO2max in individuals is clearly of importance to triathlon performance, energy output must be sustained for long periods of time, making economy of motion also very important. Studies suggests that competitive swimmers have better swimming economy than triathletes. However, since many triathletes have previously been competitive swimmers this finding is questionable. The finding suggests that triathletes from nonswimming backgrounds would benefit from improving swimming technique rather than concentrating training workouts solely on distance. In

  18. On relevant boundary perturbations of unitary minimal models

    International Nuclear Information System (INIS)

    Recknagel, A.; Roggenkamp, D.; Schomerus, V.

    2000-01-01

    We consider unitary Virasoro minimal models on the disk with Cardy boundary conditions and discuss deformations by certain relevant boundary operators, analogous to tachyon condensation in string theory. Concentrating on the least relevant boundary field, we can perform a perturbative analysis of renormalization group fixed points. We find that the systems always flow towards stable fixed points which admit no further (non-trivial) relevant perturbations. The new conformal boundary conditions are in general given by superpositions of 'pure' Cardy boundary conditions

  19. Review of zonal flows

    International Nuclear Information System (INIS)

    Diamond, P.H.; Itoh, S.-I.; Itoh, K.; Hahm, T.S.

    2004-10-01

    A comprehensive review of zonal flow phenomena in plasmas is presented. While the emphasis is on zonal flows in laboratory plasmas, zonal flows in nature are discussed as well. The review presents the status of theory, numerical simulation and experiments relevant to zonal flows. The emphasis is on developing an integrated understanding of the dynamics of drift wave - zonal flow turbulence by combining detailed studies of the generation of zonal flows by drift waves, the back-interaction of zonal flows on the drift waves, and the various feedback loops by which the system regulates and organizes itself. The implications of zonal flow phenomena for confinement in, and the phenomena of fusion devices are discussed. Special attention is given to the comparison of experiment with theory and to identifying direction for progress in future research. (author)

  20. User perspectives on relevance criteria

    DEFF Research Database (Denmark)

    Maglaughlin, Kelly L.; Sonnenwald, Diane H.

    2002-01-01

    , partially relevant, or not relevant to their information need; and explained their decisions in an interview. Analysis revealed 29 criteria, discussed positively and negatively, that were used by the participants when selecting passages that contributed or detracted from a document's relevance......This study investigates the use of criteria to assess relevant, partially relevant, and not-relevant documents. Study participants identified passages within 20 document representations that they used to make relevance judgments; judged each document representation as a whole to be relevant...... matter, thought catalyst), full text (e.g., audience, novelty, type, possible content, utility), journal/publisher (e.g., novelty, main focus, perceived quality), and personal (e.g., competition, time requirements). Results further indicate that multiple criteria are used when making relevant, partially...

  1. Physiology of the hormetic effect

    International Nuclear Information System (INIS)

    Totter, J.R.

    1987-01-01

    Beneficial (hormetic) effects of ionizing radiation have been largely ignored in developing radiobiological theory, chiefly because a suitable explanatory hypothesis is lacking. Examination of the relevant literature has revealed that food restriction effects in animals resemble those of low-level, low-LET, whole-body ionizing radiation exposure (without food restriction) in two major respects: increased longevity and change in the variance of longevity. These physiological changes can be interpreted as resulting from alteration of the steady-state flux of oxygen radicals which affect the endocrine balance. Oxy-radical-producing, low-level ionizing radiation exposure (whole body) is interpreted by the body as excess food intake, thus lowering the appetite and reducing caloric intake which, in turn, increases longevity. The greater variance in longevity accompanying increases in the median age at death with food restriction alters the ratio of long-lived to short-lived descendants and hastens the population's adaptation to semi-permanently diminished rates of food supply. Less variance and earlier mean ages at death result from an increased rate of food supply. Whole-body ionizing radiation exposure results in a mixed response, because it reduces caloric intake while signaling that an increase has occurred

  2. The emergence of Applied Physiology within the discipline of Physiology.

    Science.gov (United States)

    Tipton, Charles M

    2016-08-01

    Despite the availability and utilization of the physiology textbooks authored by Albrecht von Haller during the 18th century that heralded the modern age of physiology, not all physicians or physiologists were satisfied with its presentation, contents, or application to medicine. Initial reasons were fundamental disagreements between the "mechanists," represented by Boerhaave, Robinson, and von Haller, and the "vitalists," represented by the faculty and graduates of the Montpellier School of Medicine in France, notably, Bordeu and Barthez. Subsequently, objections originated from Europe, United Kingdom, and the United States in publications that focused not only on the teaching of physiology to medical and secondary students, but on the specific applications of the content of physiology to medicine, health, hygiene, pathology, and chronic diseases. At the turn of the 20th century, texts began to appear with applied physiology in their titles and in 1926, physician Samson Wright published a textbook entitled Applied Physiology that was intended for both medical students and the medical profession. Eleven years later, physicians Best and Taylor published The Physiological Basis of Medical Practice: A University of Toronto Texbook in Applied Physiology Although both sets of authors defined the connection between applied physiology and physiology, they failed to define the areas of physiology that were included within applied physiology. This was accomplished by the American Physiological Society (APS) Publications Committee in 1948 with the publication of the Journal of Appplied Physiology, that stated the word "applied" would broadly denote human physiology whereas the terms stress and environment would broadly include work, exercise, plus industrial, climatic and social factors. NIH established a study section (SS) devoted to applied physiology in 1964 which remained active until 2001 when it became amalgamated into other SSs. Before the end of the 20th century when

  3. Physiology of woody plants

    CERN Document Server

    Hazewinkel, Michiel; Pallardy, Stephen G

    1996-01-01

    This completely revised classic volume is an up-to-date synthesis of the intensive research devoted to woody plants. Intended primarily as a text for students and a reference for researchers, this interdisciplinary book should be useful to a broad range of scientists from agroforesters, agronomists, and arborists to plant pathologists, ecophysiologists, and soil scientists. Anyone interested in plant physiology will find this text invaluable. Key Features * Includes supplementary chapter summaries and lists of general references * Provides a solid foundation of reference information * Thoroughly updated classic text/reference.

  4. Physiologic and Pharmacokinetic Changes in Pregnancy

    Directory of Open Access Journals (Sweden)

    Maged eCostantine

    2014-04-01

    Full Text Available Physiologic changes in pregnancy induce profound alterations to the pharmacokinetic properties of many medications. These changes affect distribution, absorption, metabolism, and excretion of drugs, and thus may impact their pharmacodynamic properties during pregnancy. Pregnant women undergo several adaptations in many organ systems. Some adaptations are secondary to hormonal changes in pregnancy, while others occur to support the gravid woman and her developing fetus. Some of the changes in maternal physiology during pregnancy include, for example, increased maternal fat and total body water, decreased plasma protein concentrations, especially albumin, increased maternal blood volume, cardiac output and blood flow to the kidneys and uteroplacental unit, and decreased blood pressure. The maternal blood volume expansion occurs at a larger proportion than the increase in red blood cell mass, which results in physiologic anemia and hemodilution. Other physiologic changes include increased tidal volume, partially compensated respiratory alkalosis, delayed gastric emptying and gastrointestinal motility, and altered activity of hepatic drug metabolizing enzymes. Understating these changes and their profound impact on the pharmacokinetic properties of drugs in pregnancy is essential to optimize maternal and fetal health.

  5. [Anatomy and physiology of sexuality].

    Science.gov (United States)

    Cour, F; Droupy, S; Faix, A; Methorst, C; Giuliano, F

    2013-07-01

    Knowledge of the physiology of male and female sexuality has advanced considerably. Initially there is always desire with its biological neuroendocrine components and its emotional field which is particularly marked in women. There is a distinction between "spontaneous" sexual desire related to intrinsic affective, cognitive stimuli, and fantasies, and "reactive" sexual desire in response to physical arousal. There are similarities between men and women concerning the activation of cerebral zones in sexual arousal contexts in laboratory conditions. The neural pathways for sexual arousal are similar between men and women, bringing into play the sympathetic centres of the thoracic and lumbar spinal cord and, at the sacral level, the parasympathetic center and the motoneurons controlling the muscular contractions of the pelviperineal striated muscles. Genital sensitivity is mainly transmitted by the pudendal nerve in both men and women. Sexual arousal in men consists of penile erection, and ejaculation accompanied with orgasm. In women, sexual arousal causes increase in blood to flow to the vagina leading to lubrication and to the vulva leading to the erection of the clitoris and vulvar hyperaemia. The orgasm which can be multiple in women is accompanied by contractions of the striated perineal muscles. Several neurotransmitters are closely involved in the control of sexuality at the central level: dopamine, ocytocin, serotonin, and peripheral: nitric oxide and noradrenaline in men, vasoactive intestinal peptide and neuropeptide Y in women. Copyright © 2012. Published by Elsevier Masson SAS.

  6. Starting physiology: bioelectrogenesis.

    Science.gov (United States)

    Baptista, Vander

    2015-12-01

    From a Cartesian perspective of rational analysis, the electric potential difference across the cell membrane is one of the fundamental concepts for the study of physiology. Unfortunately, undergraduate students often struggle to understand the genesis of this energy gradient, which makes the teaching activity a hard task for the instructor. The topic of bioelectrogenesis encompasses multidisciplinary concepts, involves several mechanisms, and is a dynamic process, i.e., it never turns off during the lifetime of the cell. Therefore, to improve the transmission and acquisition of knowledge in this field, I present an alternative didactic model. The design of the model assumes that it is possible to build, in a series of sequential steps, an assembly of proteins within the membrane of an isolated cell in a simulated electrophysiology experiment. Initially, no proteins are inserted in the membrane and the cell is at a baseline energy state; the extracellular and intracellular fluids are at thermodynamic equilibrium. Students are guided through a sequence of four steps that add key membrane transport proteins to the model cell. The model is simple at the start and becomes progressively more complex, finally producing transmembrane chemical and electrical gradients. I believe that this didactic approach helps instructors with a more efficient tool for the teaching of the mechanisms of resting membrane potential while helping students avoid common difficulties that may be encountered when learning this topic. Copyright © 2015 The American Physiological Society.

  7. Riparian trees as common denominators across the river flow spectrum: are ecophysiological methods useful tools in environmental flow assessments?

    CSIR Research Space (South Africa)

    Schachtschneider, K

    2014-04-01

    Full Text Available physiological differences for trees occurred along rivers of the drier flow regime spectrum (seasonal and ephemeral). As such, this physiological measurement may be a valuable indicator for water stress, while the other measurements might provide more conclusive...

  8. Physiological mechanisms underlying animal social behaviour.

    Science.gov (United States)

    Seebacher, Frank; Krause, Jens

    2017-08-19

    Many species of animal live in groups, and the group represents the organizational level within which ecological and evolutionary processes occur. Understanding these processes, therefore, relies on knowledge of the mechanisms that permit or constrain group formation. We suggest that physiological capacities and differences in physiology between individuals modify fission-fusion dynamics. Differences between individuals in locomotor capacity and metabolism may lead to fission of groups and sorting of individuals into groups with similar physiological phenotypes. Environmental impacts such as hypoxia can influence maximum group sizes and structure in fish schools by altering access to oxygenated water. The nutritional environment determines group cohesion, and the increase in information collected by the group means that individuals should rely more on social information and form more cohesive groups in uncertain environments. Changing environmental contexts require rapid responses by individuals to maintain group coordination, which are mediated by neuroendocrine signalling systems such as nonapeptides and steroid hormones. Brain processing capacity may constrain social complexity by limiting information processing. Failure to evaluate socially relevant information correctly limits social interactions, which is seen, for example, in autism. Hence, functioning of a group relies to a large extent on the perception and appropriate processing of signals from conspecifics. Many if not all physiological systems are mechanistically linked, and therefore have synergistic effects on social behaviour. A challenge for the future lies in understanding these interactive effects, which will improve understanding of group dynamics, particularly in changing environments.This article is part of the themed issue 'Physiological determinants of social behaviour in animals'. © 2017 The Author(s).

  9. Anthropometric and physiological predispositions for elite soccer.

    Science.gov (United States)

    Reilly, T; Bangsbo, J; Franks, A

    2000-09-01

    This review is focused on anthropometric and physiological characteristics of soccer players with a view to establishing their roles within talent detection, identification and development programmes. Top-class soccer players have to adapt to the physical demands of the game, which are multifactorial. Players may not need to have an extraordinary capacity within any of the areas of physical performance but must possess a reasonably high level within all areas. This explains why there are marked individual differences in anthropometric and physiological characteristics among top players. Various measurements have been used to evaluate specific aspects of the physical performance of both youth and adult soccer players. The positional role of a player is related to his or her physiological capacity. Thus, midfield players and full-backs have the highest maximal oxygen intakes ( > 60 ml x kg(-1) x min(-1)) and perform best in intermittent exercise tests. On the other hand, midfield players tend to have the lowest muscle strength. Although these distinctions are evident in adult and elite youth players, their existence must be interpreted circumspectly in talent identification and development programmes. A range of relevant anthropometric and physiological factors can be considered which are subject to strong genetic influences (e.g. stature and maximal oxygen intake) or are largely environmentally determined and susceptible to training effects. Consequently, fitness profiling can generate a useful database against which talented groups may be compared. No single method allows for a representative assessment of a player's physical capabilities for soccer. We conclude that anthropometric and physiological criteria do have a role as part of a holistic monitoring of talented young players.

  10. The mean Evershed flow

    Science.gov (United States)

    Hu, W.-R.

    1984-09-01

    The paper gives a theoretical analysis of the overall characteristics of the Evershed flow (one of the main features of sunspots), with particular attention given to its outward flow from the umbra in the photosphere, reaching a maximum somewhere in the penumbra, and decreasing rapidly further out, and its inward flow of a comparable magnitude in chromosphere. Because the inertial force of the flow is small, the relevant dynamic process can be divided into a base state and a perturbation. The base-state solution yields the equilibrium relations between the pressure gradient, the Lorentz force, and gravity, and the flow law. The perturbation describes the force driving the Evershed flow. Since the pressure gradient in the base state is already in equilibrium with the Lorentz force and the gravity, the driving force of the mean Evershed flow is small.

  11. Monochloramine Cometabolism by Nitrifying Biofilm Relevant ...

    Science.gov (United States)

    Recently, biological monochloramine removal (i.e., cometabolism) by a pure culture ammonia–oxidizing bacteria, Nitrosomonas europaea, and a nitrifying mixed–culture have been shown to increase monochloramine demand. Although important, these previous suspended culture batch kinetic experiments were not representative of drinking water distribution systems where bacteria grow predominantly as biofilm attached to pipe walls or sediments and physiological differences may exist between suspension and biofilm growth. Therefore, the current research was an important next step in extending the previous results to investigate monochloramine cometabolism by biofilm grown in annular reactors under drinking water relevant conditions. Estimated monochloramine cometabolism kinetics were similar to those of ammonia metabolism, and monochloramine cometabolism was a significant loss mechanism (25–40% of the observed monochloramine loss). These results demonstrated that monochloramine cometabolism occurred in drinking water relevant nitrifying biofilm; thus, cometabolism may be a significant contribution to monochloramine loss during nitrification episodes in distribution systems. Investigate whether or not nitrifying biofilm can biologically transform monochloramine under drinking water relevant conditions.

  12. Invasive physiological indices to determine the functional significance of coronary stenosis

    Directory of Open Access Journals (Sweden)

    Firas R. AL-Obaidi

    2018-03-01

    Full Text Available Physiological measurements are now commonly used to assess coronary lesions in the cardiac catheterisation laboratory, and this practice is evidence-based and supported by clinical guidelines. Fractional flow reserve is currently the gold standard method to determine whether coronary lesions are functionally significant, and is used to guide revascularization. There are however several other physiological measurements that have been proposed as alternatives to the fractional flow reserve. This review aims to comprehensively discuss physiological indices that can be used in the cardiac catheterisation laboratory to determine the functional significance of coronary lesions. We will focus on their advantages and disadvantages, and the current evidence supporting their use. Keywords: Coronary physiology, Fractional flow reserve, Resting physiological indices, Coronary flow reserve

  13. Home geriatric physiological measurements.

    Science.gov (United States)

    Tamura, Toshiyo

    2012-10-01

    In an ageing society, the elderly can be monitored with numerous physiological, physical and passive devices. Sensors can be installed in the home for continuous mobility assistance and unobtrusive disease prevention. This review presents several modern sensors, which improve the quality of life and assist the elderly, disabled people and their caregivers. The main concept of geriatric sensors is that they are capable of providing assistance without limiting or disturbing the subject's daily routine, giving him or her greater comfort, pleasure and well-being. Furthermore, this review includes associated technologies of wearable/implantable monitoring systems and the 'smart-house' project. This review concludes by discussing future challenges of the future aged society.

  14. Home geriatric physiological measurements

    International Nuclear Information System (INIS)

    Tamura, Toshiyo

    2012-01-01

    In an ageing society, the elderly can be monitored with numerous physiological, physical and passive devices. Sensors can be installed in the home for continuous mobility assistance and unobtrusive disease prevention. This review presents several modern sensors, which improve the quality of life and assist the elderly, disabled people and their caregivers. The main concept of geriatric sensors is that they are capable of providing assistance without limiting or disturbing the subject's daily routine, giving him or her greater comfort, pleasure and well-being. Furthermore, this review includes associated technologies of wearable/implantable monitoring systems and the ‘smart-house’ project. This review concludes by discussing future challenges of the future aged society. (topical review)

  15. Physiology for engineers applying engineering methods to physiological systems

    CERN Document Server

    Chappell, Michael

    2016-01-01

    This book provides an introduction to qualitative and quantitative aspects of human physiology. It looks at biological and physiological processes and phenomena, including a selection of mathematical models, showing how physiological problems can be mathematically formulated and studied. It also illustrates how a wide range of engineering and physics topics, including electronics, fluid dynamics, solid mechanics and control theory can be used to describe and understand physiological processes and systems. Throughout the text there are introductions to measuring and quantifying physiological processes using both signal and imaging technologies. Physiology for Engineers describes the basic structure and models of cellular systems, the structure and function of the cardiovascular system, the electrical and mechanical activity of the heart and provides an overview of the structure and function of the respiratory and nervous systems. It also includes an introduction to the basic concepts and applications of reacti...

  16. Correlation between vortices and wall shear stress in a curved artery model under pulsatile flow conditions

    Science.gov (United States)

    Cox, Christopher; Plesniak, Michael W.

    2017-11-01

    One of the most physiologically relevant factors within the cardiovascular system is the wall shear stress. The wall shear stress affects endothelial cells via mechanotransduction and atherosclerotic regions are strongly correlated with curvature and branching in the human vasculature, where the shear stress is both oscillatory and multidirectional. Also, the combined effect of curvature and pulsatility in cardiovascular flows produces unsteady vortices. In this work, our goal is to assess the correlation between multiple vortex pairs and wall shear stress. To accomplish this, we use an in-house high-order flux reconstruction Navier-Stokes solver to simulate pulsatile flow of a Newtonian blood-analog fluid through a rigid 180° curved artery model. We use a physiologically relevant flow rate and generate results using both fully developed and uniform entrance conditions, the latter motivated by the fact that flow upstream to a curved artery may not be fully developed. Under these two inflow conditions, we characterize the evolution of various vortex pairs and their subsequent effect on several wall shear stress metrics. Supported by GW Center for Biomimetics and Bioinspired Engineering.

  17. Physiological regulation of epithelial sodium channel by proteolysis

    DEFF Research Database (Denmark)

    Svenningsen, Per; Friis, Ulla G; Bistrup, Claus

    2011-01-01

    PURPOSE OF REVIEW: Activation of epithelial sodium channel (ENaC) by proteolysis appears to be relevant for day-to-day physiological regulation of channel activity in kidney and other epithelial tissues. Pathophysiogical, proteolytic activation of ENaC in kidney has been demonstrated in proteinuric...

  18. Relevance of human anatomy in daily clinical practice.

    Science.gov (United States)

    Arráez-Aybar, Luis-Alfonso; Sánchez-Montesinos, Indalecio; Mirapeix, Rosa-M; Mompeo-Corredera, Blanca; Sañudo-Tejero, Jose-Ramón

    2010-12-20

    the aim of this study has been to evaluate the relevance of gross human anatomy in daily clinical practice and to compare it to that of other basic sciences (biochemistry, bioethics, cytohistology, microbiology, pharmacology, physiology, psychology). a total of 1250 questionnaires were distributed among 38 different medical speciality professionals. Answers were analyzed taking into account speciality (medical, surgery and others), professional status (training physician or staff member) and professional experience. the response rate was 42.9% (n=536). Gross human anatomy was considered the most relevant basic discipline for surgical specialists, while pharmacology and physiology were most relevant for medical specialists. Knowledge of anatomy was also considered fundamental for understanding neurological or musculoskeletal disorders. In undergraduate programmes, the most important focuses in teaching anatomy were radiological, topographical and functional anatomy followed by systematic anatomy. In daily medical practice anatomy was considered basic for physical examination, symptom interpretation and interpretation of radiological images. When professional status or professional experience was considered, small variations were shown and there were no significant differences related to gender or community. our results underline the relevance of basic sciences (gross anatomy, physiology, and pharmacology) in daily professional activity. Evidence-based studies such as ours, lend greater credibility and objectivity to the role of gross anatomy in the undergraduate training of health professionals and should help to establish a more appropriate curriculum for future professionals. 2010 Elsevier GmbH. All rights reserved.

  19. Procedures of Exercise Physiology Laboratories

    Science.gov (United States)

    Bishop, Phillip A.; Fortney, Suzanne; Greenisen, Michael; Siconolfi, Steven F.; Bamman, Marcas M.; Moore, Alan D., Jr.; Squires, William

    1998-01-01

    This manual describes the laboratory methods used to collect flight crew physiological performance data at the Johnson Space Center. The Exercise Countermeasures Project Laboratory is a standard physiology laboratory; only the application to the study of human physiological adaptations to spaceflight is unique. In the absence of any other recently published laboratory manual, this manual should be a useful document staffs and students of other laboratories.

  20. [Physiological features of skin ageing in human].

    Science.gov (United States)

    Tikhonova, I V; Tankanag, A V; Chemeris, N K

    2013-01-01

    The issue deals with the actual problem of gerontology, notably physiological features of human skin ageing. In the present review the authors have considered the kinds of ageing, central factors, affected on the ageing process (ultraviolet radiation and oxidation stress), as well as the research guidelines of the ageing changes in the skin structure and fuctions: study of mechanical properties, microcirculation, pH and skin thickness. The special attention has been payed to the methods of assessment of skin blood flow, and to results of investigations of age features of peripheral microhemodynamics. The laser Doppler flowmetry technique - one of the modern, noninvasive and extensively used methods for the assessmant of skin blood flow microcirculation system has been expanded in the review. The main results of the study of the ageing changes of skin blood perfusion using this method has been also presented.

  1. Cardiovascular Physiology of Dinosaurs.

    Science.gov (United States)

    Seymour, Roger S

    2016-11-01

    Cardiovascular function in dinosaurs can be inferred from fossil evidence with knowledge of how metabolic rate, blood flow rate, blood pressure, and heart size are related to body size in living animals. Skeletal stature and nutrient foramen size in fossil femora provide direct evidence of a high arterial blood pressure, a large four-chambered heart, a high aerobic metabolic rate, and intense locomotion. But was the heart of a huge, long-necked sauropod dinosaur able to pump blood up 9 m to its head? ©2016 Int. Union Physiol. Sci./Am. Physiol. Soc.

  2. When pain and hunger collide; psychological influences on differences in brain activity during physiological and non-physiological gastric distension.

    Science.gov (United States)

    Coen, S J

    2011-06-01

    Functional neuroimaging has been used extensively in conjunction with gastric balloon distension in an attempt to unravel the relationship between the brain, regulation of hunger, satiety, and food intake tolerance. A number of researchers have also adopted a more physiological approach using intra-gastric administration of a liquid meal which has revealed different brain responses to gastric balloon distension. These differences are important as they question the utility and relevance of non-physiological models such as gastric balloon distension, especially when investigating mechanisms of feeding behavior such as satiety. However, an assessment of the relevance of physiological versus non-physiological gastric distension has been problematic due to differences in distension volumes between studies. In this issue of Neurogastroenterology and Motility, Geeraerts et al. compare brain activity during volume matched nutrient gastric distension and balloon distension in healthy volunteers. Gastric balloon distension activated the 'visceral pain neuromatrix'. This network of brain regions was deactivated during nutrient infusion, supporting the notion that brain activity during physiological versus non-physiological distension is indeed different. The authors suggest deactivation of the pain neuromatrix during nutrient infusion serves as a prerequisite for tolerance of normal meal volumes in health. © 2011 Blackwell Publishing Ltd.

  3. Conservation physiology of marine fishes

    DEFF Research Database (Denmark)

    Jørgensen, Christian; Peck, Myron A.; Antognarelli, Fabio

    2012-01-01

    At the end of May, 17 scientists involved in an EU COST Action on Conservation Physiology of Marine Fishes met in Oristano, Sardinia, to discuss how physiology can be better used in modelling tools to aid in management of marine ecosystems. Current modelling approaches incorporate physiology...... to different extents, ranging from no explicit consideration to detailed physiological mechanisms, and across scales from a single fish to global fishery resources. Biologists from different sub-disciplines are collaborating to rise to the challenge of projecting future changes in distribution and productivity...

  4. Artificial intelligence, physiological genomics, and precision medicine.

    Science.gov (United States)

    Williams, Anna Marie; Liu, Yong; Regner, Kevin R; Jotterand, Fabrice; Liu, Pengyuan; Liang, Mingyu

    2018-04-01

    Big data are a major driver in the development of precision medicine. Efficient analysis methods are needed to transform big data into clinically-actionable knowledge. To accomplish this, many researchers are turning toward machine learning (ML), an approach of artificial intelligence (AI) that utilizes modern algorithms to give computers the ability to learn. Much of the effort to advance ML for precision medicine has been focused on the development and implementation of algorithms and the generation of ever larger quantities of genomic sequence data and electronic health records. However, relevance and accuracy of the data are as important as quantity of data in the advancement of ML for precision medicine. For common diseases, physiological genomic readouts in disease-applicable tissues may be an effective surrogate to measure the effect of genetic and environmental factors and their interactions that underlie disease development and progression. Disease-applicable tissue may be difficult to obtain, but there are important exceptions such as kidney needle biopsy specimens. As AI continues to advance, new analytical approaches, including those that go beyond data correlation, need to be developed and ethical issues of AI need to be addressed. Physiological genomic readouts in disease-relevant tissues, combined with advanced AI, can be a powerful approach for precision medicine for common diseases.

  5. Modeling of Cerebral Oxygen Transport Based on In vivo Microscopic Imaging of Microvascular Network Structure, Blood Flow, and Oxygenation.

    Science.gov (United States)

    Gagnon, Louis; Smith, Amy F; Boas, David A; Devor, Anna; Secomb, Timothy W; Sakadžić, Sava

    2016-01-01

    Oxygen is delivered to brain tissue by a dense network of microvessels, which actively control cerebral blood flow (CBF) through vasodilation and contraction in response to changing levels of neural activity. Understanding these network-level processes is immediately relevant for (1) interpretation of functional Magnetic Resonance Imaging (fMRI) signals, and (2) investigation of neurological diseases in which a deterioration of neurovascular and neuro-metabolic physiology contributes to motor and cognitive decline. Experimental data on the structure, flow and oxygen levels of microvascular networks are needed, together with theoretical methods to integrate this information and predict physiologically relevant properties that are not directly measurable. Recent progress in optical imaging technologies for high-resolution in vivo measurement of the cerebral microvascular architecture, blood flow, and oxygenation enables construction of detailed computational models of cerebral hemodynamics and oxygen transport based on realistic three-dimensional microvascular networks. In this article, we review state-of-the-art optical microscopy technologies for quantitative in vivo imaging of cerebral microvascular structure, blood flow and oxygenation, and theoretical methods that utilize such data to generate spatially resolved models for blood flow and oxygen transport. These "bottom-up" models are essential for the understanding of the processes governing brain oxygenation in normal and disease states and for eventual translation of the lessons learned from animal studies to humans.

  6. Respiratory physiology during early life.

    Science.gov (United States)

    Stocks, J

    1999-08-01

    Despite the rapid adaptation to extrauterine life, the respiratory system of an infant is not simply a miniaturized version of that of an adult, since the rapid somatic growth that occurs during the first year of life is accompanied by major developmental changes in respiratory physiology. The highly compliant chest wall of the infant results in relatively low transpulmonary pressures at end expiration with increased tendency of the small peripheral airways to close during tidal breathing. This not only impairs gas exchange and ventilation-perfusion balance, particularly in dependent parts of the lung, but, together with the small absolute size of the airways, renders the infant and young child particularly susceptible to airway obstruction. Premature airways are highly compliant structures compared with those of mature newborns or adults. This increased compliance can cause airway collapse, resulting in increased airways resistance, flow limitation, poor gas exchange and increased work of breathing. Although there is clear evidence that airway reactivity is present from birth, its role in wheezing lower respiratory tract illnesses in young infants may be overshadowed by pre-existing abnormalities of airway geometry and lung mechanics, or by pathological changes such as airway oedema and mucus hypersecretion. Attempts to assess age-related changes in airway reactivity or response to aerosol therapy in the very young is confounded by changes in breathing patterns and the fact that infants are preferential nose breathers. There is increasing evidence that pre-existing abnormalities of respiratory function, associated with adverse events during foetal life (including maternal smoking during pregnancy), and familial predisposition to wheezing are important determinants of wheezing illnesses during the first years of life. This emphasizes the need to identify and minimize any factors that threaten the normal development of the lung during this critical period if

  7. Smolt physiology and endocrinology

    Science.gov (United States)

    McCormick, Stephen D.; McCormick, Stephen D.; Farrell, Anthony Peter; Brauner, Colin J.

    2013-01-01

    Hormones play a critical role in maintaining body fluid balance in euryhaline fishes during changes in environmental salinity. The neuroendocrine axis senses osmotic and ionic changes, then signals and coordinates tissue-specific responses to regulate water and ion fluxes. Rapid-acting hormones, e.g. angiotensins, cope with immediate challenges by controlling drinking rate and the activity of ion transporters in the gill, gut, and kidney. Slow-acting hormones, e.g. prolactin and growth hormone/insulin-like growth factor-1, reorganize the body for long-term acclimation by altering the abundance of ion transporters and through cell proliferation and differentiation of ionocytes and other osmoregulatory cells. Euryhaline species exist in all groups of fish, including cyclostomes, and cartilaginous and teleost fishes. The diverse strategies for responding to changes in salinity have led to differential regulation and tissue-specific effects of hormones. Combining traditional physiological approaches with genomic, transcriptomic, and proteomic analyses will elucidate the patterns and diversity of the endocrine control of euryhalinity.

  8. Polyamines in plant physiology

    Science.gov (United States)

    Galston, A. W.; Sawhney, R. K.

    1990-01-01

    The diamine putrescine, the triamine spermidine, and the tetramine spermine are ubiquitous in plant cells, while other polyamines are of more limited occurrence. Their chemistry and pathways of biosynthesis and metabolism are well characterized. They occur in the free form as cations, but are often conjugated to small molecules like phenolic acids and also to various macromolecules. Their titer varies from approximately micromolar to more than millimolar, and depends greatly on environmental conditions, especially stress. In cereals, the activity of one of the major polyamine biosynthetic enzymes, arginine decarboxylase, is rapidly and dramatically increased by almost every studied external stress, leading to 50-fold or greater increases in putrescine titer within a few hours. The physiological significance of this increase is not yet clear, although most recent work suggests an adaptive, protective role. Polyamines produced through the action of ornithine decarboxylase, by contrast, seem essential for DNA replication and cell division. The application of exogenous polyamines produces effects on patterns of senescence and morphogenesis, suggesting but not proving a regulatory role for polyamines in these processes. The evidence for such a regulatory role is growing.

  9. Clinical physiology grand rounds.

    Science.gov (United States)

    Richards, Jeremy; Schwartzstein, Richard; Irish, Julie; Almeida, Jacqueline; Roberts, David

    2013-04-01

    Clinical Physiology Grand Rounds (CPGR) is an interactive, case-based conference for medical students designed to: (1) integrate preclinical and clinical learning; (2) promote inductive clinical reasoning; and (3) emphasise students as peer teachers. CPGR specifically encourages mixed learning level student interactions and emphasises the use of concept mapping. We describe the theoretical basis and logistical considerations for an interactive, integrative, mixed-learner environment such as CPGR. In addition, we report qualitative data regarding students' attitudes towards and perceptions of CPGR. Medical students from first to fourth year participate in a monthly, interactive conference. The CPGR was designed to bridge gaps and reinforce linkages between basic science and clinical concepts, and to incorporate interactive vertical integration between preclinical and clinical students. Medical education and content experts use Socratic, interactive teaching methods to develop real-time concept maps to emphasise the presence and importance of linkages across curricula. Student focus groups were held to assess attitudes towards and perceptions of the mixed-learner environment and concept maps in CPGR. Qualitative analyses of focus group transcripts were performed to develop themes and codes describing the students' impressions of CPGR. CPGR is a case-based, interactive conference designed to help students gain an increased appreciation of linkages between basic science and clinical medicine concepts, and an increased awareness of clinical reasoning thought processes. Success is dependent upon explicit attention being given to goals for students' integrated learning. © Blackwell Publishing Ltd 2013.

  10. Regulating plant physiology with organic electronics.

    Science.gov (United States)

    Poxson, David J; Karady, Michal; Gabrielsson, Roger; Alkattan, Aziz Y; Gustavsson, Anna; Doyle, Siamsa M; Robert, Stéphanie; Ljung, Karin; Grebe, Markus; Simon, Daniel T; Berggren, Magnus

    2017-05-02

    The organic electronic ion pump (OEIP) provides flow-free and accurate delivery of small signaling compounds at high spatiotemporal resolution. To date, the application of OEIPs has been limited to delivery of nonaromatic molecules to mammalian systems, particularly for neuroscience applications. However, many long-standing questions in plant biology remain unanswered due to a lack of technology that precisely delivers plant hormones, based on cyclic alkanes or aromatic structures, to regulate plant physiology. Here, we report the employment of OEIPs for the delivery of the plant hormone auxin to induce differential concentration gradients and modulate plant physiology. We fabricated OEIP devices based on a synthesized dendritic polyelectrolyte that enables electrophoretic transport of aromatic substances. Delivery of auxin to transgenic Arabidopsis thaliana seedlings in vivo was monitored in real time via dynamic fluorescent auxin-response reporters and induced physiological responses in roots. Our results provide a starting point for technologies enabling direct, rapid, and dynamic electronic interaction with the biochemical regulation systems of plants.

  11. Differences in Perceived and Physiologic Genital Arousal Between Women With and Without Sexual Dysfunction.

    Science.gov (United States)

    Handy, Ariel B; Stanton, Amelia M; Pulverman, Carey S; Meston, Cindy M

    2018-01-01

    a role in women's experience of sexual dysfunction and might be more clinically relevant for women with sexual dysfunction than genital blood flow. This study's large sample is unique in sexual psychophysiology, and it strengthens the credibility of the findings. However, this study is limited in that arousal-specific dysfunction was determined with self-report measures, not by a clinician-administered assessment. These findings suggest distinct response trajectories in women with and without sexual dysfunction, and although perceived genital responses are important for women who are experiencing problems with arousal, they do not seem to be related to objective measures of physiologic arousal. Handy AB, Stanton AM, Pulverman CS, Meston CM. Differences in Perceived and Physiologic Genital Arousal Between Women With and Without Sexual Dysfunction. J Sex Med 2018;15:52-63. Copyright © 2017 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

  12. On the marginally relevant operator in z=2 Lifshitz holography

    International Nuclear Information System (INIS)

    Holsheimer, Kristian

    2014-01-01

    We study holographic renormalization and RG flow in a strongly-coupled Lifshitz-type theory in 2+1 dimensions with dynamical exponent z=2. The bottom-up gravity dual we use is 3+1 dimensional Einstein gravity coupled to a massive vector field. This model contains a marginally relevant operator around the Lifshitz fixed point. We show how holographic renormalization works in the presence of this marginally relevant operator without the need to introduce explicitly cutoff-dependent counterterms. A simple closed-form expression is found for the renormalized on-shell action. We also discuss how asymptotically Lifshitz geometries flow to AdS in the interior due to the marginally relevant operator. We study the behavior of the renormalized entanglement entropy and confirm that it decreases monotonically along the Lifshitz-to-AdS RG flow

  13. Astrophysical Flows

    Science.gov (United States)

    Pringle, James E.; King, Andrew

    2003-07-01

    Almost all conventional matter in the Universe is fluid, and fluid dynamics plays a crucial role in astrophysics. This new graduate textbook provides a basic understanding of the fluid dynamical processes relevant to astrophysics. The mathematics used to describe these processes is simplified to bring out the underlying physics. The authors cover many topics, including wave propagation, shocks, spherical flows, stellar oscillations, the instabilities caused by effects such as magnetic fields, thermal driving, gravity, shear flows, and the basic concepts of compressible fluid dynamics and magnetohydrodynamics. The authors are Directors of the UK Astrophysical Fluids Facility (UKAFF) at the University of Leicester, and editors of the Cambridge Astrophysics Series. This book has been developed from a course in astrophysical fluid dynamics taught at the University of Cambridge. It is suitable for graduate students in astrophysics, physics and applied mathematics, and requires only a basic familiarity with fluid dynamics.• Provides coverage of the fundamental fluid dynamical processes an astrophysical theorist needs to know • Introduces new mathematical theory and techniques in a straightforward manner • Includes end-of-chapter problems to illustrate the course and introduce additional ideas

  14. Physiologic effects of bowel preparation

    DEFF Research Database (Denmark)

    Holte, Kathrine; Nielsen, Kristine Grubbe; Madsen, Jan Lysgård

    2004-01-01

    PURPOSE: Despite the universal use of bowel preparation before colonoscopy and colorectal surgery, the physiologic effects have not been described in a standardized setting. This study was designed to investigate the physiologic effects of bowel preparation. METHODS: In a prospective study, 12...

  15. Homer W. Smith's contribution to renal physiology.

    Science.gov (United States)

    Giebisch, Gerhard

    2004-01-01

    Homer Smith was, for three decades, from the 1930s until his death in 1962, one of the leaders in the field of renal physiology. His contributions were many: he played a major role in introducing and popularizing renal clearance methods, introduced non-invasive methods for the measurement of glomerular filtration rate, of renal blood flow and tubular transport capacity, and provided novel insights into the mechanisms of excretion of water and electrolytes. Homer Smith's contributions went far beyond his personal investigations. He was a superb writer of several inspiring textbooks of renal physiology that exerted great and lasting influence on the development of renal physiology. Smith's intellectual insights and ability for critical analysis of data allowed him to create broad concepts that defined the functional properties of glomeruli, tubules and the renal circulation. A distinguishing feature of Homer Smith's career was his close contact and collaboration, over many years, with several clinicians of his alma mater, New York University. For initiating these pathophysiological investigations, he is justly credited to have advanced, in a major way, our understanding of altered renal function in disease. Smith's lasting scientific impact is also reflected by a whole school of investigators that trained with him and who applied his methods, analyses and concepts to the study of renal function all over the world. So great was his influence and preeminence that Robert Pitts, in his excellent tribute to Homer Smith in the Memoirs of the National Academy of Science states that his death brought an end to what might be aptly called the Smithian Era of renal physiology.

  16. Computation of tokamak equilibria with steady flow

    International Nuclear Information System (INIS)

    Kerner, W.; Tokuda, Shinji

    1987-08-01

    The equations for ideal MHD equilibria with stationary flow are reexamined and addressed as numerically applied to tokamak configurations with a free plasma boundary. Both the isothermal (purely toroidal flow) and the poloidal flow cases are treated. Experiment-relevant states with steady flow (so far only in the toroidal direction) are computed by the modified SELENE40 code. (author)

  17. A physiological toxicokinetic model for dermal absorption of waterborne pyrene by trout

    Energy Technology Data Exchange (ETDEWEB)

    Namdari, R.; Law, F.C.P. [Simon Fraser Univ., Burnaby, British Columbia (Canada)

    1995-12-31

    A physiologically-based toxicokinetic (PB-TK) model was developed to describe the disposition of pyrene in trout following a bolus injection into the dorsal aorta. In the present study, the PB-TK model was adapted for dermal absorption of waterborne pyrene by trout. A skin compartment with transdermal flux described mathematically by the permeability-area-concentration product was added to the PB-TK model to allow prediction of pyrene concentrations in target organs and blood on the basis of exposure concentration at the skin surface. Physiologically relevant parameters e.g., organ volume, blood flow rate, and tissue/blood partitioning coefficient which were derived from the model were similar to those reported in the previous publication. The dermal PB-TK model was validated by exposing the trunk of trout (400--500 g) to stagnant water containing 24 ppm pyrene in a specially designed chamber for 4 hr, 24 hr or 48 hr. The trout were sacrificed at the conclusion of pyrene exposure and the tissues analyzed for unchanged pyrene by HPLC. In separate experiments, trout were implanted with dorsal aorta cannuli before the trunks were exposed to stagnant water containing 24 ppm pyrene in the chamber for 4 hr. At specific time intervals during and after pyrene exposure, blood samples were withdrawn through the cannula and analyzed for pyrene by HPLC. The agreement between simulated and experimentally obtained values shows that this model is an appropriate tool to predict dermal absorption of waterborne pyrene by trout.

  18. Cassava biology and physiology.

    Science.gov (United States)

    El-Sharkawy, Mabrouk A

    2004-11-01

    Cassava or manioc (Manihot esculenta Crantz), a perennial shrub of the New World, currently is the sixth world food crop for more than 500 million people in tropical and sub-tropical Africa, Asia and Latin America. It is cultivated mainly by resource-limited small farmers for its starchy roots, which are used as human food either fresh when low in cyanogens or in many processed forms and products, mostly starch, flour, and for animal feed. Because of its inherent tolerance to stressful environments, where other food crops would fail, it is often considered a food-security source against famine, requiring minimal care. Under optimal environmental conditions, it compares favorably in production of energy with most other major staple food crops due to its high yield potential. Recent research at the Centro Internacional de Agricultura Tropical (CIAT) in Colombia has demonstrated the ability of cassava to assimilate carbon at very high rates under high levels of humidity, temperature and solar radiation,which correlates with productivity across all environments whether dry or humid. When grown on very poor soils under prolonged drought for more than 6 months, the crop reduce both its leaf canopy and transpiration water loss, but its attached leaves remain photosynthetically active, though at greatly reduced rates. The main physiological mechanism underlying such a remarkable tolerance to drought was rapid stomatal closure under both atmospheric and edaphic water stress, protecting the leaf against dehydration while the plant depletes available soil water slowly during long dry periods. This drought tolerance mechanism leads to high crop water use efficiency values. Although the cassava fine root system is sparse, compared to other crops, it can penetrate below 2 m soil,thus enabling the crop to exploit deep water if available. Leaves of cassava and wild Manihot possess elevated activities of the C4 enzyme PEP carboxylase but lack the leaf Kranz anatomy typical of C4

  19. Comparative Digestive Physiology

    Science.gov (United States)

    Karasov, William H.; Douglas, Angela E.

    2015-01-01

    In vertebrates and invertebrates, morphological and functional features of gastrointestinal (GI) tracts generally reflect food chemistry, such as content of carbohydrates, proteins, fats, and material(s) refractory to rapid digestion (e.g., cellulose). The expression of digestive enzymes and nutrient transporters approximately matches the dietary load of their respective substrates, with relatively modest excess capacity. Mechanisms explaining differences in hydrolase activity between populations and species include gene copy number variations and single-nucleotide polymorphisms. Transcriptional and posttranscriptional adjustments mediate phenotypic changes in the expression of hydrolases and transporters in response to dietary signals. Many species respond to higher food intake by flexibly increasing digestive compartment size. Fermentative processes by symbiotic microorganisms are important for cellulose degradation but are relatively slow, so animals that rely on those processes typically possess special enlarged compartment(s) to maintain a microbiota and other GI structures that slow digesta flow. The taxon richness of the gut microbiota, usually identified by 16S rRNA gene sequencing, is typically an order of magnitude greater in vertebrates than invertebrates, and the interspecific variation in microbial composition is strongly influenced by diet. Many of the nutrient transporters are orthologous across different animal phyla, though functional details may vary (e.g., glucose and amino acid transport with K+ rather than Na+ as a counter ion). Paracellular absorption is important in many birds. Natural toxins are ubiquitous in foods and may influence key features such as digesta transit, enzymatic breakdown, microbial fermentation, and absorption PMID:23720328

  20. Profiles of Dialogue for Relevance

    Directory of Open Access Journals (Sweden)

    Douglas Walton

    2016-12-01

    Full Text Available This paper uses argument diagrams, argumentation schemes, and some tools from formal argumentation systems developed in artificial intelligence to build a graph-theoretic model of relevance shown to be applicable (with some extensions as a practical method for helping a third party judge issues of relevance or irrelevance of an argument in real examples. Examples used to illustrate how the method works are drawn from disputes about relevance in natural language discourse, including a criminal trial and a parliamentary debate.

  1. Flow cytometry, fluorescent probes, and flashing bacteria

    NARCIS (Netherlands)

    Bunthof, C.J.

    2002-01-01


    Key words: fluorescent probes, flow cytometry, CSLM, viability, survival, microbial physiology, lactic acid bacteria, Lactococcus lactis , Lactobacillus plantarum , cheese, milk,

  2. Using Stimulation of the Diving Reflex in Humans to Teach Integrative Physiology

    Science.gov (United States)

    Choate, Julia K.; Denton, Kate M.; Evans, Roger G.; Hodgson, Yvonne

    2014-01-01

    During underwater submersion, the body responds by conserving O[subscript 2] and prioritizing blood flow to the brain and heart. These physiological adjustments, which involve the nervous, cardiovascular, and respiratory systems, are known as the diving response and provide an ideal example of integrative physiology. The diving reflex can be…

  3. Relevance theory: pragmatics and cognition.

    Science.gov (United States)

    Wearing, Catherine J

    2015-01-01

    Relevance Theory is a cognitively oriented theory of pragmatics, i.e., a theory of language use. It builds on the seminal work of H.P. Grice(1) to develop a pragmatic theory which is at once philosophically sensitive and empirically plausible (in both psychological and evolutionary terms). This entry reviews the central commitments and chief contributions of Relevance Theory, including its Gricean commitment to the centrality of intention-reading and inference in communication; the cognitively grounded notion of relevance which provides the mechanism for explaining pragmatic interpretation as an intention-driven, inferential process; and several key applications of the theory (lexical pragmatics, metaphor and irony, procedural meaning). Relevance Theory is an important contribution to our understanding of the pragmatics of communication. © 2014 John Wiley & Sons, Ltd.

  4. Clinical relevance in anesthesia journals

    DEFF Research Database (Denmark)

    Lauritsen, Jakob; Møller, Ann M

    2006-01-01

    The purpose of this review is to present the latest knowledge and research on the definition and distribution of clinically relevant articles in anesthesia journals. It will also discuss the importance of the chosen methodology and outcome of articles.......The purpose of this review is to present the latest knowledge and research on the definition and distribution of clinically relevant articles in anesthesia journals. It will also discuss the importance of the chosen methodology and outcome of articles....

  5. A mathematical model of coronary blood flow control: simulation of patient-specific three-dimensional hemodynamics during exercise.

    Science.gov (United States)

    Arthurs, Christopher J; Lau, Kevin D; Asrress, Kaleab N; Redwood, Simon R; Figueroa, C Alberto

    2016-05-01

    This work presents a mathematical model of the metabolic feedback and adrenergic feedforward control of coronary blood flow that occur during variations in the cardiac workload. It is based on the physiological observations that coronary blood flow closely follows myocardial oxygen demand, that myocardial oxygen debts are repaid, and that control oscillations occur when the system is perturbed and so are phenomenological in nature. Using clinical data, we demonstrate that the model can provide patient-specific estimates of coronary blood flow changes between rest and exercise, requiring only the patient's heart rate and peak aortic pressure as input. The model can be used in zero-dimensional lumped parameter network studies or as a boundary condition for three-dimensional multidomain Navier-Stokes blood flow simulations. For the first time, this model provides feedback control of the coronary vascular resistance, which can be used to enhance the physiological accuracy of any hemodynamic simulation, which includes both a heart model and coronary arteries. This has particular relevance to patient-specific simulation for which heart rate and aortic pressure recordings are available. In addition to providing a simulation tool, under our assumptions, the derivation of our model shows that β-feedforward control of the coronary microvascular resistance is a mathematical necessity and that the metabolic feedback control must be dependent on two error signals: the historical myocardial oxygen debt, and the instantaneous myocardial oxygen deficit. Copyright © 2016 the American Physiological Society.

  6. Physiology knowledge plays a role when novices learn technical echocardiography skills

    DEFF Research Database (Denmark)

    Nielsen, Dorte Guldbrand; Gøtzsche, Ole; Eika, Berit

    2010-01-01

    Purpose: Little is known about factors of relevance for achieving technical skills of echocardiography (TTE); one of the essential skills defined by the European Society of Cardiology Core Curriculum. In an earlier study we have shown that there is a strong correlation between physiology knowledge...... and interpretation skills of intermediately trained echocardiographers. This study investigates the role of physiology knowledge in the development of echocardiographic technical expertise. Methods: Forty-five physicians (15 novices, 15 intermediates and 15 experts) were evaluated on technical skills. Participants...... of echocardiography relevant physiology knowledge. Results: A strong and significant correlation between expertise level and technical checklist scores was found (r = .76, p

  7. Critical Issues in Modelling Lymph Node Physiology

    Directory of Open Access Journals (Sweden)

    Dmitry Grebennikov

    2016-12-01

    Full Text Available In this study, we discuss critical issues in modelling the structure and function of lymph nodes (LNs, with emphasis on how LN physiology is related to its multi-scale structural organization. In addition to macroscopic domains such as B-cell follicles and the T cell zone, there are vascular networks which play a key role in the delivery of information to the inner parts of the LN, i.e., the conduit and blood microvascular networks. We propose object-oriented computational algorithms to model the 3D geometry of the fibroblastic reticular cell (FRC network and the microvasculature. Assuming that a conduit cylinder is densely packed with collagen fibers, the computational flow study predicted that the diffusion should be a dominating process in mass transport than convective flow. The geometry models are used to analyze the lymph flow properties through the conduit network in unperturbed- and damaged states of the LN. The analysis predicts that elimination of up to 60%–90% of edges is required to stop the lymph flux. This result suggests a high degree of functional robustness of the network.

  8. A generic whole body physiologically based pharmacokinetic model for therapeutic proteins in PK-Sim.

    Science.gov (United States)

    Niederalt, Christoph; Kuepfer, Lars; Solodenko, Juri; Eissing, Thomas; Siegmund, Hans-Ulrich; Block, Michael; Willmann, Stefan; Lippert, Jörg

    2018-04-01

    Proteins are an increasingly important class of drugs used as therapeutic as well as diagnostic agents. A generic physiologically based pharmacokinetic (PBPK) model was developed in order to represent at whole body level the fundamental mechanisms driving the distribution and clearance of large molecules like therapeutic proteins. The model was built as an extension of the PK-Sim model for small molecules incorporating (i) the two-pore formalism for drug extravasation from blood plasma to interstitial space, (ii) lymph flow, (iii) endosomal clearance and (iv) protection from endosomal clearance by neonatal Fc receptor (FcRn) mediated recycling as especially relevant for antibodies. For model development and evaluation, PK data was used for compounds with a wide range of solute radii. The model supports the integration of knowledge gained during all development phases of therapeutic proteins, enables translation from pre-clinical species to human and allows predictions of tissue concentration profiles which are of relevance for the analysis of on-target pharmacodynamic effects as well as off-target toxicity. The current implementation of the model replaces the generic protein PBPK model available in PK-Sim since version 4.2 and becomes part of the Open Systems Pharmacology Suite.

  9. Role of coronary physiology in the contemporary management of coronary artery disease

    Science.gov (United States)

    Ruparelia, Neil; Kharbanda, Rajesh K

    2015-01-01

    Coronary artery disease (CAD) remains the leading cause of death worldwide with approximately 1 in 30 patients with stable CAD experiencing death or acute myocardial infarction each year. The presence and extent of resultant myocardial ischaemia has been shown to confer an increased risk of adverse outcomes. Whilst, optimal medical therapy (OMT) forms the cornerstone of the management of patients with stable CAD, a significant number of patients present with ischaemia refractory to OMT. Historically coronary angiography alone has been used to determine coronary lesion severity in both stable and acute settings. It is increasingly clear that this approach fails to accurately identify the haemodynamic significance of lesions; especially those that are visually “intermediate” in severity. Revascularisation based upon angiographic appearances alone may not reduce coronary events above OMT. Technological advances have enabled the measurement of physiological indices including the fractional flow reserve, the index of microcirculatory resistance and the coronary flow reserve. The integration of these parameters into the routine management of patients presenting to the cardiac catheterization laboratory with CAD represents a critical adjunctive tool in the optimal management of these patients by identifying patients that would most benefit from revascularisation and importantly also highlighting patients that would not gain benefit and therefore reducing the likelihood of adverse outcomes associated with coronary revascularisation. Furthermore, these techniques are applicable to a broad range of patients including those with left main stem disease, proximal coronary disease, diabetes mellitus, previous percutaneous coronary intervention and with previous coronary artery bypass grafting. This review will discuss current concepts relevant to coronary physiology assessment, its role in the management of both stable and acute patients and future applications. PMID

  10. Role of coronary physiology in the contemporary management of coronary artery disease.

    Science.gov (United States)

    Ruparelia, Neil; Kharbanda, Rajesh K

    2015-02-16

    Coronary artery disease (CAD) remains the leading cause of death worldwide with approximately 1 in 30 patients with stable CAD experiencing death or acute myocardial infarction each year. The presence and extent of resultant myocardial ischaemia has been shown to confer an increased risk of adverse outcomes. Whilst, optimal medical therapy (OMT) forms the cornerstone of the management of patients with stable CAD, a significant number of patients present with ischaemia refractory to OMT. Historically coronary angiography alone has been used to determine coronary lesion severity in both stable and acute settings. It is increasingly clear that this approach fails to accurately identify the haemodynamic significance of lesions; especially those that are visually "intermediate" in severity. Revascularisation based upon angiographic appearances alone may not reduce coronary events above OMT. Technological advances have enabled the measurement of physiological indices including the fractional flow reserve, the index of microcirculatory resistance and the coronary flow reserve. The integration of these parameters into the routine management of patients presenting to the cardiac catheterization laboratory with CAD represents a critical adjunctive tool in the optimal management of these patients by identifying patients that would most benefit from revascularisation and importantly also highlighting patients that would not gain benefit and therefore reducing the likelihood of adverse outcomes associated with coronary revascularisation. Furthermore, these techniques are applicable to a broad range of patients including those with left main stem disease, proximal coronary disease, diabetes mellitus, previous percutaneous coronary intervention and with previous coronary artery bypass grafting. This review will discuss current concepts relevant to coronary physiology assessment, its role in the management of both stable and acute patients and future applications.

  11. Plant aquaporins: roles in plant physiology.

    Science.gov (United States)

    Li, Guowei; Santoni, Véronique; Maurel, Christophe

    2014-05-01

    Aquaporins are membrane channels that facilitate the transport of water and small neutral molecules across biological membranes of most living organisms. Here, we present comprehensive insights made on plant aquaporins in recent years, pointing to their molecular and physiological specificities with respect to animal or microbial counterparts. In plants, aquaporins occur as multiple isoforms reflecting a high diversity of cellular localizations and various physiological substrates in addition to water. Of particular relevance for plants is the transport by aquaporins of dissolved gases such as carbon dioxide or metalloids such as boric or silicic acid. The mechanisms that determine the gating and subcellular localization of plant aquaporins are extensively studied. They allow aquaporin regulation in response to multiple environmental and hormonal stimuli. Thus, aquaporins play key roles in hydraulic regulation and nutrient transport in roots and leaves. They contribute to several plant growth and developmental processes such as seed germination or emergence of lateral roots. Plants with genetically altered aquaporin functions are now tested for their ability to improve plant resistance to stresses. This article is part of a Special Issue entitled Aquaporins. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Water-soluble triazabutadienes that release diazonium species upon protonation under physiologically relevant conditions.

    Science.gov (United States)

    Kimani, Flora W; Jewett, John C

    2015-03-23

    Triazabutadienes are an understudied structural motif that have remarkable reactivity once rendered water-soluble. It is shown that these molecules readily release diazonium species in a pH-dependent manner in a series of buffer solutions with pH ranges similar to those found in cells. Upon further development, we expect that this process will be well suited to cargo-release strategies and organelle-specific bioconjugation reactions. These compounds offer one of the mildest ways of generating diazonium species in aqueous solutions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. RODENT LEYDIG CELL TUMORIGENESIS: A REVIEW OF THE PHYSIOLOGY, PATHOLOGY, MECHANISMS, AND RELEVANCE TO HUMANS

    Science.gov (United States)

    Leydig cells (LCs) are the cells of the testis that have as their primary function the production of testosterone. LCs are a common target of compounds tested in rodent carcinogenicity bioassays. The number of reviews on Leydig cell tumors (LCTs) has increased in recent years bec...

  14. Relevance of trichothecenes in fungal physiology: Disruption of tri5 in Trichoderma arundinaceum

    Science.gov (United States)

    Trichothecenes are sesquiterpenoid mycotoxins produced mainly by Fusarium species. Harzianum A (HA), a non-phytotoxic trichothecene produced by Trichoderma arundinaceum, has recently been found to have antagonistic activity against fungal plant pathogens and to induce plant genes involved in defense...

  15. Molecular and physiological responses to abiotic stress in forest trees and their relevance to tree improvement.

    Science.gov (United States)

    Harfouche, Antoine; Meilan, Richard; Altman, Arie

    2014-11-01

    Abiotic stresses, such as drought, salinity and cold, are the major environmental stresses that adversely affect tree growth and, thus, forest productivity, and play a major role in determining the geographic distribution of tree species. Tree responses and tolerance to abiotic stress are complex biological processes that are best analyzed at a systems level using genetic, genomic, metabolomic and phenomic approaches. This will expedite the dissection of stress-sensing and signaling networks to further support efficient genetic improvement programs. Enormous genetic diversity for stress tolerance exists within some forest-tree species, and due to advances in sequencing technologies the molecular genetic basis for this diversity has been rapidly unfolding in recent years. In addition, the use of emerging phenotyping technologies extends the suite of traits that can be measured and will provide us with a better understanding of stress tolerance. The elucidation of abiotic stress-tolerance mechanisms will allow for effective pyramiding of multiple tolerances in a single tree through genetic engineering. Here we review recent progress in the dissection of the molecular basis of abiotic stress tolerance in forest trees, with special emphasis on Populus, Pinus, Picea, Eucalyptus and Quercus spp. We also outline practices that will enable the deployment of trees engineered for abiotic stress tolerance to land owners. Finally, recommendations for future work are discussed. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Relevance of Peptide Uptake Systems to the Physiology and Virulence of Streptococcus agalactiae

    OpenAIRE

    Samen, Ulrike; Gottschalk, Birgit; Eikmanns, Bernhard J.; Reinscheid, Dieter J.

    2004-01-01

    Streptococcus agalactiae is a major cause of invasive infections in human newborns. To satisfy its growth requirements, S. agalactiae takes up 9 of the 20 proteinogenic amino acids from the environment. Defined S. agalactiae mutants in one or several of four putative peptide permease systems were constructed and tested for peptide uptake, growth in various media, and expression of virulence traits. Oligopeptide uptake by S. agalactiae was shown to be mediated by the ABC transporter OppA1-F, w...

  17. Combinatorial polymer electrospun matrices promote physiologically-relevant cardiomyogenic stem cell differentiation.

    Directory of Open Access Journals (Sweden)

    Mukesh K Gupta

    Full Text Available Myocardial infarction results in extensive cardiomyocyte death which can lead to fatal arrhythmias or congestive heart failure. Delivery of stem cells to repopulate damaged cardiac tissue may be an attractive and innovative solution for repairing the damaged heart. Instructive polymer scaffolds with a wide range of properties have been used extensively to direct the differentiation of stem cells. In this study, we have optimized the chemical and mechanical properties of an electrospun polymer mesh for directed differentiation of embryonic stem cells (ESCs towards a cardiomyogenic lineage. A combinatorial polymer library was prepared by copolymerizing three distinct subunits at varying molar ratios to tune the physicochemical properties of the resulting polymer: hydrophilic polyethylene glycol (PEG, hydrophobic poly(ε-caprolactone (PCL, and negatively-charged, carboxylated PCL (CPCL. Murine ESCs were cultured on electrospun polymeric scaffolds and their differentiation to cardiomyocytes was assessed through measurements of viability, intracellular reactive oxygen species (ROS, α-myosin heavy chain expression (α-MHC, and intracellular Ca(2+ signaling dynamics. Interestingly, ESCs on the most compliant substrate, 4%PEG-86%PCL-10%CPCL, exhibited the highest α-MHC expression as well as the most mature Ca(2+ signaling dynamics. To investigate the role of scaffold modulus in ESC differentiation, the scaffold fiber density was reduced by altering the electrospinning parameters. The reduced modulus was found to enhance α-MHC gene expression, and promote maturation of myocyte Ca(2+ handling. These data indicate that ESC-derived cardiomyocyte differentiation and maturation can be promoted by tuning the mechanical and chemical properties of polymer scaffold via copolymerization and electrospinning techniques.

  18. LEFT VENTRICULAR ROTATION, TWIST AND UNTWIST: PHYSIOLOGICAL ROLE AND CLINICAL RELEVANCE

    Directory of Open Access Journals (Sweden)

    E. N. Pavlyukova

    2015-09-01

    Full Text Available The helical ventricular myocardial band of Torrent-Guasp is a new concept, which provides strong grounds for reconciliation of some important aspects in cardiovascular medicine. Oblique fiber orientation provides left ventricular rotation, which in addition to radial thickening and longitudinal shortening, is predicted as an essential component of the effective left ventricular pumping. Left ventricular rotation can be measured in clinical practice noninvasively using echocardiography and this provides new opportunities for the assessment of different aspects of left ventricular mechanical function.

  19. Flow Control for Supersonic Inlet Applications

    Science.gov (United States)

    2014-06-10

    1221-1233, May 2013 3. Loth, E., Titchener, N., Babinsky, H., Povinelli , L., “Canonical NSBLI Flows Relevant to External Compression Inlets”, AIAA J...Tennessee, Jan. 9-12, 2012 7. Loth, E.L., Titchener, N., Babinsky, H., Povinelli , L.A., “A Canonical Normal SBLI Flow Relevant to External

  20. Conservation physiology of animal migration

    Science.gov (United States)

    Lennox, Robert J.; Chapman, Jacqueline M.; Souliere, Christopher M.; Tudorache, Christian; Wikelski, Martin; Metcalfe, Julian D.; Cooke, Steven J.

    2016-01-01

    Migration is a widespread phenomenon among many taxa. This complex behaviour enables animals to exploit many temporally productive and spatially discrete habitats to accrue various fitness benefits (e.g. growth, reproduction, predator avoidance). Human activities and global environmental change represent potential threats to migrating animals (from individuals to species), and research is underway to understand mechanisms that control migration and how migration responds to modern challenges. Focusing on behavioural and physiological aspects of migration can help to provide better understanding, management and conservation of migratory populations. Here, we highlight different physiological, behavioural and biomechanical aspects of animal migration that will help us to understand how migratory animals interact with current and future anthropogenic threats. We are in the early stages of a changing planet, and our understanding of how physiology is linked to the persistence of migratory animals is still developing; therefore, we regard the following questions as being central to the conservation physiology of animal migrations. Will climate change influence the energetic costs of migration? Will shifting temperatures change the annual clocks of migrating animals? Will anthropogenic influences have an effect on orientation during migration? Will increased anthropogenic alteration of migration stopover sites/migration corridors affect the stress physiology of migrating animals? Can physiological knowledge be used to identify strategies for facilitating the movement of animals? Our synthesis reveals that given the inherent challenges of migration, additional stressors derived from altered environments (e.g. climate change, physical habitat alteration, light pollution) or interaction with human infrastructure (e.g. wind or hydrokinetic turbines, dams) or activities (e.g. fisheries) could lead to long-term changes to migratory phenotypes. However, uncertainty remains

  1. Shippingport: A relevant decommissioning project

    International Nuclear Information System (INIS)

    Crimi, F.P.

    1988-01-01

    Because of Shippingport's low electrical power rating (72 MWe), there has been some misunderstanding on the relevancy of the Shippingport Station Decommissioning Project (SSDP) to a modern 1175 MWe commercial pressurized water reactor (PWR) power station. This paper provides a comparison of the major components of the reactor plant of the 72 MWe Shippingport Atomic Power Station and an 1175 MWe nuclear plant and the relevancy of the Shippingport decommissioning as a demonstration project for the nuclear industry. For the purpose of this comparison, Portland General Electric Company's 1175 MWe Trojan Nuclear Plant at Rainier, Oregon, has been used as the reference nuclear power plant. 2 refs., 2 figs., 1 tab

  2. Interpretation of physiological indicators of motivation: Caveats and recommendations.

    Science.gov (United States)

    Richter, Michael; Slade, Kate

    2017-09-01

    Motivation scientists employing physiological measures to gather information about motivation-related states are at risk of committing two fundamental errors: overstating the inferences that can be drawn from their physiological measures and circular reasoning. We critically discuss two complementary approaches, Cacioppo and colleagues' model of psychophysiological relations and construct validation theory, to highlight the conditions under which these errors are committed and provide guidance on how to avoid them. In particular, we demonstrate that the direct inference from changes in a physiological measure to changes in a motivation-related state requires the demonstration that the measure is not related to other relevant psychological states. We also point out that circular reasoning can be avoided by separating the definition of the motivation-related state from the hypotheses that are empirically tested. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Integrating physiological regulation with stem cell and tissue homeostasis

    Science.gov (United States)

    Nakada, Daisuke; Levi, Boaz P.; Morrison, Sean J.

    2015-01-01

    Summary Stem cells are uniquely able to self-renew, to undergo multilineage differentiation, and to persist throughout life in a number of tissues. Stem cells are regulated by a combination of shared and tissue-specific mechanisms and are distinguished from restricted progenitors by differences in transcriptional and epigenetic regulation. Emerging evidence suggests that other aspects of cellular physiology, including mitosis, signal transduction, and metabolic regulation also differ between stem cells and their progeny. These differences may allow stem cells to be regulated independently of differentiated cells in response to circadian rhythms, changes in metabolism, diet, exercise, mating, aging, infection, and disease. This allows stem cells to sustain homeostasis or to remodel relevant tissues in response to physiological change. Stem cells are therefore not only regulated by short-range signals that maintain homeostasis within their tissue of origin, but also by long-range signals that integrate stem cell function with systemic physiology. PMID:21609826

  4. Bringing physiology into PET of the liver.

    Science.gov (United States)

    Keiding, Susanne

    2012-03-01

    Several physiologic features make interpretation of PET studies of liver physiology an exciting challenge. As with other organs, hepatic tracer kinetics using PET is quantified by dynamic recording of the liver after the administration of a radioactive tracer, with measurements of time-activity curves in the blood supply. However, the liver receives blood from both the portal vein and the hepatic artery, with the peak of the portal vein time-activity curve being delayed and dispersed compared with that of the hepatic artery. The use of a flow-weighted dual-input time-activity curve is of importance for the estimation of hepatic blood perfusion through initial dynamic PET recording. The portal vein is inaccessible in humans, and methods of estimating the dual-input time-activity curve without portal vein measurements are being developed. Such methods are used to estimate regional hepatic blood perfusion, for example, by means of the initial part of a dynamic (18)F-FDG PET/CT recording. Later, steady-state hepatic metabolism can be assessed using only the arterial input, provided that neither the tracer nor its metabolites are irreversibly trapped in the prehepatic splanchnic area within the acquisition period. This is used in studies of regulation of hepatic metabolism of, for example, (18)F-FDG and (11)C-palmitate.

  5. Ecological principles relevant to nuclear war

    International Nuclear Information System (INIS)

    Hutchinson, T.C.; Cropper, W.P. Jr.; Grover, H.D.

    1985-01-01

    The ecological principles outlined are very basic ones; the authors anticipate a readership trained in a broad range of disciplines, including those unfamiliar with the academic discipline of ecology. The authors include substantial discussion on ecophysiology (i.e., the responses of organisms to their environment) because this is relevant to the new understanding of the potential climatic consequences of nuclear war. In particular, the physiological sensitivity of organisms to reduced levels of light and temperature are a key part of the analysis of the potential ecological effects and agricultural effects of nuclear war. Much of the ecological analysis has been organized around major biological units called biomes. The authors describe the biome concept and discuss some of the environmental-climatic factors that are believed to control biome distribution. Emphasis is given to plants because of their controlling influence on ecosystem functions through their role as primary producers. Future reports are needed to address more fully the potential effects on animals. Much more research needs to be done on both plant and animal responses to the types of perturbations possible for the aftermath of a nuclear war. Another important element for analysis of the potential ecological consequences of nuclear war concerns recovery processes. As the post-nuclear war environmental extremes ameliorate, ecological communities in devastated regions would begin to reorganize. It is not possible to predict the course of such a succession precisely, but some principles concerning post-perturbation replacement (such as seed banks and germination), relevant successional patterns, and organism strategies are discussed

  6. Medical student attitudes toward kidney physiology and nephrology: a qualitative study.

    Science.gov (United States)

    Roberts, John K; Sparks, Matthew A; Lehrich, Ruediger W

    2016-11-01

    Interest in nephrology among trainees is waning in the USA. Early perceptions and attitudes to subject matter can be linked to the quality of pre-clinical curricula. We wanted to explore these attitudes in the setting of modern curriculum redesign. We utilized Q methodology to understand first-year medical student attitudes after an innovative kidney physiology curriculum redesign that focuses on blending multiple learning methods. First-year medical students were invited to take a Q sort survey at the conclusion of a kidney physiology course. Students prioritized statements related to their understanding of kidney physiology, learning preferences, preferred course characteristics, perceived clinical relevance of kidney physiology, and interest in nephrology as a career. Factor analysis was performed to identify different student viewpoints. At the conclusion of our modified course, all students (n = 108) were invited to take the survey and 44 (41%) Q sorts were returned. Two dominant viewpoints were defined according to interest in nephrology. The Potentials are students who understand kidney physiology, perceive kidney physiology as clinically relevant, attend class sessions, utilize videos, and are willing to shadow a nephrologist. The Uninterested are students who are less satisfied with their kidney physiology knowledge, prefer to study alone with a textbook, avoid lectures, and are not interested in learning about nephrology. In an updated renal physiology course, students that use multiple learning methods also have favorable attitudes toward learning kidney physiology. Thus, modern curriculum changes that accommodate a variety of learning styles may promote positive attitudes toward nephrology.

  7. Human health and the environment: Predicting plasma protein binding and metabolic clearance rates of environmentally relevant chemicals.

    Science.gov (United States)

    In silico methods provide a rapid, inexpensive means of screening a wide array of environmentally relevant pollutants, pesticides, fungicides and consumer products for further toxicity testing. Physiologically based pharmacokinetic (PBPK) models bridge the gap between in vitro as...

  8. Physiology of fish endocrine pancreas.

    Science.gov (United States)

    Plisetskaya, E M

    1989-06-01

    From the very beginning of physiological studies on the endocine pancreas, fish have been used as experimental subjects. Fish insulin was one of the first vertebrate insulins isolated and one of the first insulins whose primary and then tertiary structures were reported. Before a second pancreatic hormone, glucagon, was characterized, a physiologically active 'impurity', similar to that in mammalian insulin preparations, was found in fish insulins.Fish have become the most widely used model for studies of biosynthesis and processing of the pancreatic hormones. It seems inconceivable, therefore, that until the recent past cod and tuna insulins have been the only purified piscine islet hormones available for physiological experiments. The situation has changed remarkably during the last decade.In this review the contemporary status of physiological studies on the fish pancreas is outlined with an emphasis on the following topics: 1) contents of pancreatic peptides in plasma and in islet tissue; 2) actions of piscine pancreatic hormones in fish; 3) specific metabolic consequences of an acute insufficiency of pancreatic peptides; 4) functional interrelations among pancreatic peptides which differ from those of mammals. The pitfalls, lacunae and the perspectives of contemporary physiological studies on fish endocrine pancreas are outlined.

  9. Physiology in Medicine: Understanding dynamic alveolar physiology to minimize ventilator-induced lung injury.

    Science.gov (United States)

    Nieman, Gary F; Satalin, Josh; Kollisch-Singule, Michaela; Andrews, Penny; Aiash, Hani; Habashi, Nader M; Gatto, Louis A

    2017-06-01

    Acute respiratory distress syndrome (ARDS) remains a serious clinical problem with the main treatment being supportive in the form of mechanical ventilation. However, mechanical ventilation can be a double-edged sword: if set improperly, it can exacerbate the tissue damage caused by ARDS; this is known as ventilator-induced lung injury (VILI). To minimize VILI, we must understand the pathophysiologic mechanisms of tissue damage at the alveolar level. In this Physiology in Medicine paper, the dynamic physiology of alveolar inflation and deflation during mechanical ventilation will be reviewed. In addition, the pathophysiologic mechanisms of VILI will be reviewed, and this knowledge will be used to suggest an optimal mechanical breath profile (MB P : all airway pressures, volumes, flows, rates, and the duration that they are applied at both inspiration and expiration) necessary to minimize VILI. Our review suggests that the current protective ventilation strategy, known as the "open lung strategy," would be the optimal lung-protective approach. However, the viscoelastic behavior of dynamic alveolar inflation and deflation has not yet been incorporated into protective mechanical ventilation strategies. Using our knowledge of dynamic alveolar mechanics (i.e., the dynamic change in alveolar and alveolar duct size and shape during tidal ventilation) to modify the MB P so as to minimize VILI will reduce the morbidity and mortality associated with ARDS. Copyright © 2017 the American Physiological Society.

  10. Magnesium degradation under physiological conditions – Best practice

    Directory of Open Access Journals (Sweden)

    Jorge Gonzalez

    2018-06-01

    Full Text Available This review focusses on the application of physiological conditions for the mechanistic understanding of magnesium degradation. Despite the undisputed relevance of simplified laboratory setups for alloy screening purposes, realistic and predictive in vitro setups are needed. Due to the complexity of these systems, the review gives an overview about technical measures, defines some caveats and can be used as a guideline for the establishment of harmonized laboratory approaches.

  11. Cell physiology based pharmacodynamic modeling of antimicrobial drug combinations

    OpenAIRE

    Hethey, Christoph Philipp

    2017-01-01

    Mathematical models of bacterial growth have been successfully applied to study the relationship between antibiotic drug exposure and the antibacterial effect. Since these models typically lack a representation of cellular processes and cell physiology, the mechanistic integration of drug action is not possible on the cellular level. The cellular mechanisms of drug action, however, are particularly relevant for the prediction, analysis and understanding of interactions between antibiotics. In...

  12. Dramatic lives and relevant becomings

    DEFF Research Database (Denmark)

    Henriksen, Ann-Karina; Miller, Jody

    2012-01-01

    of marginality into positions of relevance. The analysis builds on empirical data from Copenhagen, Denmark, gained through ethnographic fieldwork with the participation of 20 female informants aged 13–22. The theoretical contribution proposes viewing conflicts as multi-linear, multi-causal and non...

  13. Regularization in Matrix Relevance Learning

    NARCIS (Netherlands)

    Schneider, Petra; Bunte, Kerstin; Stiekema, Han; Hammer, Barbara; Villmann, Thomas; Biehl, Michael

    A In this paper, we present a regularization technique to extend recently proposed matrix learning schemes in learning vector quantization (LVQ). These learning algorithms extend the concept of adaptive distance measures in LVQ to the use of relevance matrices. In general, metric learning can

  14. The Virtual Physiological Human ToolKit.

    Science.gov (United States)

    Cooper, Jonathan; Cervenansky, Frederic; De Fabritiis, Gianni; Fenner, John; Friboulet, Denis; Giorgino, Toni; Manos, Steven; Martelli, Yves; Villà-Freixa, Jordi; Zasada, Stefan; Lloyd, Sharon; McCormack, Keith; Coveney, Peter V

    2010-08-28

    The Virtual Physiological Human (VPH) is a major European e-Science initiative intended to support the development of patient-specific computer models and their application in personalized and predictive healthcare. The VPH Network of Excellence (VPH-NoE) project is tasked with facilitating interaction between the various VPH projects and addressing issues of common concern. A key deliverable is the 'VPH ToolKit'--a collection of tools, methodologies and services to support and enable VPH research, integrating and extending existing work across Europe towards greater interoperability and sustainability. Owing to the diverse nature of the field, a single monolithic 'toolkit' is incapable of addressing the needs of the VPH. Rather, the VPH ToolKit should be considered more as a 'toolbox' of relevant technologies, interacting around a common set of standards. The latter apply to the information used by tools, including any data and the VPH models themselves, and also to the naming and categorizing of entities and concepts involved. Furthermore, the technologies and methodologies available need to be widely disseminated, and relevant tools and services easily found by researchers. The VPH-NoE has thus created an online resource for the VPH community to meet this need. It consists of a database of tools, methods and services for VPH research, with a Web front-end. This has facilities for searching the database, for adding or updating entries, and for providing user feedback on entries. Anyone is welcome to contribute.

  15. The physiological basis and application of renal radionuclide studies

    International Nuclear Information System (INIS)

    Britton, K.E.

    1983-01-01

    A knowledge of the basic physiology of the kidney is essential for an understanding of the application of radionuclide studies in clinical practice. A knowledge of the physiology of the kidney allows one to develop physiological models that are isomorphic and then apply the appropriate type of data analysis in relationship to these models. In this way mistakes in the type of analysis can be avoided and a strong basis for the interpretation of renal radionuclide studies in health and disease is thereby provided. Methods for measuring total renal function, the contribution of each kidney to total renal function, the presence or absence of obstructive nephropathy and the determination of the relative flows to the cortical and juxtamedullary nephrons are given as examples of this approach. (author)

  16. Noninvasive physiologic assessment of coronary stenoses using cardiac CT.

    Science.gov (United States)

    Xu, Lei; Sun, Zhonghua; Fan, Zhanming

    2015-01-01

    Coronary CT angiography (CCTA) has become an important noninvasive imaging modality in the diagnosis of coronary artery disease (CAD). CCTA enables accurate evaluation of coronary artery stenosis. However, CCTA provides limited information on the physiological significance of stenotic lesions. A noninvasive "one-stop-shop" diagnostic test that can provide both anatomical significance and functional significance of stenotic lesions would be beneficial in the diagnosis and management of CAD. Recently, with the introduction of novel techniques, such as myocardial CT perfusion, CT-derived fractional flow reserve (FFRCT), and transluminal attenuation gradient (TAG), CCTA has emerged as a noninvasive method for the assessment of both anatomy of coronary lesions and its physiological consequences during a single study. This review provides an overview of the current status of new CT techniques for the physiologic assessments of CAD.

  17. Noninvasive Physiologic Assessment of Coronary Stenoses Using Cardiac CT

    Directory of Open Access Journals (Sweden)

    Lei Xu

    2015-01-01

    Full Text Available Coronary CT angiography (CCTA has become an important noninvasive imaging modality in the diagnosis of coronary artery disease (CAD. CCTA enables accurate evaluation of coronary artery stenosis. However, CCTA provides limited information on the physiological significance of stenotic lesions. A noninvasive “one-stop-shop” diagnostic test that can provide both anatomical significance and functional significance of stenotic lesions would be beneficial in the diagnosis and management of CAD. Recently, with the introduction of novel techniques, such as myocardial CT perfusion, CT-derived fractional flow reserve (FFRCT, and transluminal attenuation gradient (TAG, CCTA has emerged as a noninvasive method for the assessment of both anatomy of coronary lesions and its physiological consequences during a single study. This review provides an overview of the current status of new CT techniques for the physiologic assessments of CAD.

  18. Stimulating Student Interest in Physiology: The Intermedical School Physiology Quiz

    Science.gov (United States)

    Cheng, Hwee-Ming

    2010-01-01

    The Intermedical School Physiology Quiz (IMSPQ) was initiated in 2003 during the author's last sabbatical from the University of Malaya. At this inaugural event, there were just seven competing teams from Malaysian medical schools. The challenge trophy for the IMSPQ is named in honor of Prof. A. Raman, who was the first Malaysian Professor of…

  19. From Physiology to Prevention: Further remarks on a physiological imperative

    Directory of Open Access Journals (Sweden)

    B Jouanjean

    2012-05-01

    Full Text Available Physiology, is the fundamental and functional expression of life. It is the study of all the representative functions of Man in all his capacities, and in particular, his capacity to work. It is very possible to establish a link between a physiological and physiopathological state, the capacity of work and the economy, which can be understood as the articulation between the physiological capacities of Man and the production of work. If these functions are innately acquired by Man they are likewise maintained by regulatory functions throughout life. The stability of these regulatory mechanisms represent the state of good health. The management of this state, constitutes Primary Prevention where both chronic and acute physiopathology defines an alteration in these regulatory mechanisms. We deduce from this reasoning that a tripartite management adapted to the physiological situation is viable and that by choosing parameters specific to individual and collective behavior, it is possible to inject, and combine, at each level and to each demand in order to budget a healthcare system in a more balanced and equitable way. 

  20. Extracellular vesicles: fundamentals and clinical relevance

    Directory of Open Access Journals (Sweden)

    Wael Nassar

    2015-01-01

    Full Text Available All types of cells of eukaryotic organisms produce and release small nanovesicles into their extracellular environment. Early studies have described these vesicles as ′garbage bags′ only to remove obsolete cellular molecules. Valadi and colleagues, in 2007, were the first to discover the capability of circulating extracellular vesicles (EVs to horizontally transfer functioning gene information between cells. These extracellular vesicles express components responsible for angiogenesis promotion, stromal remodeling, chemoresistance, genetic exchange, and signaling pathway activation through growth factor/receptor transfer. EVs represent an important mode of intercellular communication by serving as vehicles for transfer between cells of membrane and cytosolic proteins, lipids, signaling proteins, and RNAs. They contribute to physiology and pathology, and they have a myriad of potential clinical applications in health and disease. Moreover, vesicles can pass the blood-brain barrier and may perhaps even be considered as naturally occurring liposomes. These cell-derived EVs not only represent a central mediator of the disease microenvironment, but their presence in the peripheral circulation may serve as a surrogate for disease biopsies, enabling real-time diagnosis and disease monitoring. In this review, we′ll be addressing the characteristics of different types of extracellular EVs, as well as their clinical relevance and potential as diagnostic markers, and also define therapeutic options.

  1. Stress response assessment of Lactobacillus sakei strains selected as potential autochthonous starter cultures by flow cytometry and nucleic acid double-staining analyses.

    Science.gov (United States)

    Bonomo, M G; Milella, L; Martelli, G; Salzano, G

    2013-09-01

    The aim of this study was to apply the flow cytometry to Lactobacillus sakei strains, selected as potential autochthonous starters, to investigate dynamics and physiological heterogeneity of microbial behaviour under different stress conditions. A simultaneous nucleic acid double-staining assay was applied to discriminate cell populations in different physiological states after exposure to heat (50 and 55°C) and acid (pH 2·5 and 3·0) stresses. Alive cells with intact membranes, damaged cells still alive but with injured membranes, so with even a recovery ability, and dead cells with a permanent membrane damage were differentiated with a significant increase in damaged cells after stronger stress treatments. The existence and characteristics of subpopulations displaying heterogeneity in particular conditions are highly relevant, because specific subpopulations may show improved survival, changes and dynamics under stress conditions. This assay has potential for physiological research on lactic acid bacteria and for application in the food industry. The assessment of intermediate physiological states in Lb. sakei strains with recovery possibility could be an important criterion for application of potential starter cultures. Application of flow cytometry and characterization of sorted subpopulations may contribute to further understanding of diversity and heterogeneity in physiology of bacterial populations. © 2013 The Society for Applied Microbiology.

  2. The Limits of Exercise Physiology

    DEFF Research Database (Denmark)

    Gabriel, Brendan M; Zierath, Juleen R

    2017-01-01

    Many of the established positive health benefits of exercise have been documented by historical discoveries in the field of exercise physiology. These investigations often assess limits: the limits of performance, or the limits of exercise-induced health benefits. Indeed, several key findings have...... been informed by studying highly trained athletes, in addition to healthy or unhealthy people. Recent progress has been made in regard to skeletal muscle metabolism and personalized exercise regimes. In this perspective, we review some of the historical milestones of exercise physiology, discuss how...

  3. Flow Velocities After Carotid Artery Stenting: Impact of Stent Design. A Fluid Dynamics Study in a Carotid Artery Model with Laser Doppler Anemometry

    International Nuclear Information System (INIS)

    Greil, Oliver; Kleinschmidt, Thomas; Weiss, Wolfgang; Wolf, Oliver; Heider, Peter; Schaffner, Silvio; Gianotti, Marc; Schmid, Thomas; Liepsch, Dieter; Berger, Hermann

    2005-01-01

    Purpose. To study the influence of a newly developed membrane stent design on flow patterns in a physiologic carotid artery model. Methods. Three different stents were positioned in silicone models of the carotid artery: a stainless steel stent (Wall-stent), a nitinol stent (SelfX), and a nitinol stent with a semipermeable membrane (MembraX). To increase the contact area of the membrane with the vessel wall, another MembranX model was modified at the outflow tract. The membrane consists of a biocompatible silicone-polyurethane copolymer (Elast-Eon) with a pore size of 100 μm. All stents were deployed across the bifurcation and the external carotid artery origin. Flow velocity measurements were performed with laser Doppler anemometry (LDA), using pulsatile flow conditions (Re = 220; flow 0.39 l/min; flow rate ratio ICA:ECA = 70:30) in hemodynamically relevant cross-sections. The hemodynamic changes were analyzed by comparing velocity fluctuations of corresponding flow profiles. Results. The flow rate ratio ICA:ECA shifted significantly from 70/30 to 73.9/26.1 in the MembraX and remained nearly unchanged in the SelfX and Wallstent. There were no changes in the flow patterns at the inflow proximal to the stents. In the stent no relevant changes were found in the SelfX. In the Wallstent the separation zone shifted from the orifice of the ICA to the distal end of the stent. Four millimeters distal to the SelfX and the Wallstent the flow profile returned to normal. In the MembraX an increase in the central slipstreams was found with creation of a flow separation distal to the stent. With a modification of the membrane this flow separation vanished. In the ECA flow disturbances were seen at the inner wall distal to the stent struts in the SelfX and the Wallstent. With the MembraX a calming of flow could be observed in the ECA with a slight loss of flow volume. Conclusions. Stent placement across the carotid artery bifurcation induces alterations of the physiologic flow

  4. Personality, emotion, and individual differences in physiological responses.

    Science.gov (United States)

    Stemmler, Gerhard; Wacker, Jan

    2010-07-01

    A dominant paradigm in biopsychological personality research seeks to establish links between emotional and motivational traits and habitual, transsituationally consistent individual differences in measures of physiological activity. An alternative approach conceptualizes traits as dispositions that are only operative in certain situational contexts and consequently predicts associations between emotional and motivational traits and physiological activity only for trait-relevant situational contexts in which the physiological systems underlying the traits in question are engaged. In the present paper we first examine and contrast these personistic and interactionistic conceptualizations of personality and personality-physiology associations and then present data from several large studies (N>100) in which electrocortical (e.g., frontal alpha asymmetry) and somatovisceral parameters were measured in various situational contexts (e.g., after the induction of either anger, or fear, or anxiety). As predicted by the interactionistic conceptualization of traits as dispositions the situational context and its subjective representation by the participants moderated the personality-physiology relationships for measures of both central and peripheral nervous system activity. We conclude by outlining the implications of the interactionistic approach for biopsychological personality research. Copyright © 2009 Elsevier B.V. All rights reserved.

  5. Nigerian Journal of Physiological Sciences: Editorial Policies

    African Journals Online (AJOL)

    Focus and Scope. Nigerian Journal of Physiological Sciences (Niger. J. Physiol. Sci.) is a biannual publication of the Physiological Society of Nigeria. It covers diverse areas of research in physiological sciences, publishing reviews in current research areas and original laboratory and clinical research in physiological ...

  6. Physiologically assessed hot flashes and endothelial function among midlife women.

    Science.gov (United States)

    Thurston, Rebecca C; Chang, Yuefang; Barinas-Mitchell, Emma; Jennings, J Richard; von Känel, Roland; Landsittel, Doug P; Matthews, Karen A

    2017-08-01

    Hot flashes are experienced by most midlife women. Emerging data indicate that they may be associated with endothelial dysfunction. No studies have tested whether hot flashes are associated with endothelial function using physiologic measures of hot flashes. We tested whether physiologically assessed hot flashes were associated with poorer endothelial function. We also considered whether age modified associations. Two hundred seventy-two nonsmoking women reporting either daily hot flashes or no hot flashes, aged 40 to 60 years, and free of clinical cardiovascular disease, underwent ambulatory physiologic hot flash and diary hot flash monitoring; a blood draw; and ultrasound measurement of brachial artery flow-mediated dilation to assess endothelial function. Associations between hot flashes and flow-mediated dilation were tested in linear regression models controlling for lumen diameter, demographics, cardiovascular disease risk factors, and estradiol. In multivariable models incorporating cardiovascular disease risk factors, significant interactions by age (P hot flashes (beta [standard error] = -2.07 [0.79], P = 0.01), and more frequent physiologic hot flashes (for each hot flash: beta [standard error] = -0.10 [0.05], P = 0.03, multivariable) were associated with lower flow-mediated dilation. Associations were not accounted for by estradiol. Associations were not observed among the older women (age 54-60 years) or for self-reported hot flash frequency, severity, or bother. Among the younger women, hot flashes explained more variance in flow-mediated dilation than standard cardiovascular disease risk factors or estradiol. Among younger midlife women, frequent hot flashes were associated with poorer endothelial function and may provide information about women's vascular status beyond cardiovascular disease risk factors and estradiol.

  7. Modeling physiological resistance in bacterial biofilms.

    Science.gov (United States)

    Cogan, N G; Cortez, Ricardo; Fauci, Lisa

    2005-07-01

    A mathematical model of the action of antimicrobial agents on bacterial biofilms is presented. The model includes the fluid dynamics in and around the biofilm, advective and diffusive transport of two chemical constituents and the mechanism of physiological resistance. Although the mathematical model applies in three dimensions, we present two-dimensional simulations for arbitrary biofilm domains and various dosing strategies. The model allows the prediction of the spatial evolution of bacterial population and chemical constituents as well as different dosing strategies based on the fluid motion. We find that the interaction between the nutrient and the antimicrobial agent can reproduce survival curves which are comparable to other model predictions as well as experimental results. The model predicts that exposing the biofilm to low concentration doses of antimicrobial agent for longer time is more effective than short time dosing with high antimicrobial agent concentration. The effects of flow reversal and the roughness of the fluid/biofilm are also investigated. We find that reversing the flow increases the effectiveness of dosing. In addition, we show that overall survival decreases with increasing surface roughness.

  8. Physiological Responses to Thermal Stress and Exercise

    Science.gov (United States)

    Iyota, Hiroyuki; Ohya, Akira; Yamagata, Junko; Suzuki, Takashi; Miyagawa, Toshiaki; Kawabata, Takashi

    The simple and noninvasive measuring methods of bioinstrumentation in humans is required for optimization of air conditioning and management of thermal environments, taking into consideration the individual specificity of the human body as well as the stress conditions affecting each. Changes in human blood circulation were induced with environmental factors such as heat, cold, exercise, mental stress, and so on. In this study, the physiological responses of human body to heat stress and exercise were investigated in the initial phase of the developmental research. We measured the body core and skin temperatures, skin blood flow, and pulse wave as the indices of the adaptation of the cardiovascular system. A laser Doppler skin blood flowmetry using an optical-sensor with a small portable data logger was employed for the measurement. These results reveal the heat-stress and exercise-induced circulatory responses, which are under the control of the sympathetic nerve system. Furthermore, it was suggested that the activity of the sympathetic nervous system could be evaluated from the signals of the pulse wave included in the signals derived from skin blood flow by means of heart rate variability assessments and detecting peak heights of velocity-plethysmogram.

  9. The Improved Relevance Voxel Machine

    DEFF Research Database (Denmark)

    Ganz, Melanie; Sabuncu, Mert; Van Leemput, Koen

    The concept of sparse Bayesian learning has received much attention in the machine learning literature as a means of achieving parsimonious representations of features used in regression and classification. It is an important family of algorithms for sparse signal recovery and compressed sensing....... Hence in its current form it is reminiscent of a greedy forward feature selection algorithm. In this report, we aim to solve the problems of the original RVoxM algorithm in the spirit of [7] (FastRVM).We call the new algorithm Improved Relevance Voxel Machine (IRVoxM). Our contributions...... and enables basis selection from overcomplete dictionaries. One of the trailblazers of Bayesian learning is MacKay who already worked on the topic in his PhD thesis in 1992 [1]. Later on Tipping and Bishop developed the concept of sparse Bayesian learning [2, 3] and Tipping published the Relevance Vector...

  10. Biology and Mechanics of Blood Flows Part I: Biology

    CERN Document Server

    Thiriet, Marc

    2008-01-01

    Biology and Mechanics of Blood Flows presents the basic knowledge and state-of-the-art techniques necessary to carry out investigations of the cardiovascular system using modeling and simulation. Part I of this two-volume sequence, Biology, addresses the nanoscopic and microscopic scales. The nanoscale corresponds to the scale of biochemical reaction cascades involved in cell adaptation to mechanical stresses among other stimuli. The microscale is the scale of stress-induced tissue remodeling associated with acute or chronic loadings. The cardiovascular system, like any physiological system, has a complicated three-dimensional structure and composition. Its time dependent behavior is regulated, and this complex system has many components. In this authoritative work, the author provides a survey of relevant cell components and processes, with detailed coverage of the electrical and mechanical behaviors of vascular cells, tissues, and organs. Because the behaviors of vascular cells and tissues are tightly coupl...

  11. FROM PHYSIOLOGICAL TO PATHOLOGICAL METEOSENSITIVITY

    Directory of Open Access Journals (Sweden)

    M. I. Yabluchanskiy

    2013-12-01

    Full Text Available This paper is dedicated to the problem of physiological and pathological meteosensitivity (meteodependency or meteopathy.We introduce and discuss the definition for individual meteodependency, define factors, mechanisms, clinical signs, diagnosis, and approaches to prophylaxy and treatment of individual pathological meteosensitivity.

  12. Physiological adaptation in desert birds

    NARCIS (Netherlands)

    Williams, JB; Tieleman, BI; Williams, Joseph B.

    We call into question the idea that birds have not evolved unique physiological adaptations to desert environments. The rate at which desert larks metabolize energy is lower than in mesic species within the same family, and this lower rate of living translates into a lower overall energy requirement

  13. Physiology Of Prolonged Bed Rest

    Science.gov (United States)

    Greenleaf, John E.

    1991-01-01

    Report describes physiological effects of prolonged bed rest. Rest for periods of 24 hours or longer deconditions body to some extent; healing proceeds simultaneously with deconditioning. Report provides details on shifts in fluid electrolytes and loss of lean body mass, which comprises everything in body besides fat - that is, water, muscle, and bone. Based on published research.

  14. Electronic Textbook in Human Physiology.

    Science.gov (United States)

    Broering, Naomi C.; Lilienfield, Lawrence S.

    1994-01-01

    Describes the development of an electronic textbook in human physiology at the Georgetown University Medical Center Library that was designed to enhance learning and visualization through a prototype knowledge base of core instructional materials stored in digital format on Macintosh computers. The use of computers in the medical curriculum is…

  15. Exercise Effects on Sleep Physiology

    Directory of Open Access Journals (Sweden)

    Sunao eUchida

    2012-04-01

    Full Text Available This mini-review focuses on the effects of exercise on sleep. In its early days, sleep research largely focused on central nervous system (CNS physiology using standardized tabulations of several sleep-specific landmark electroencephalogram (EEG waveforms. Though coarse, this method has enabled the observation and inspection of numerous uninterrupted sleep phenomena. Thus, research on the effects of exercise on sleep began, in the 1960’s, with a focus primarily on sleep EEG (CNS sleep changes. Those early studies found only small effects of exercise on sleep. More recent sleep research has explored not only CNS functioning, but somatic physiology as well. As physical exercise mostly affects somatic functions, endocrine and autonomic nervous system (ANS changes that occur during sleep should be affected by daytime exercise. Since endocrinological, metabolic and autonomic changes can be measured during sleep, it should be possible to assess exercise effects on somatic physiology in addition to CNS sleep quality, building from standard polysomnographic (PSG techniques. Incorporating measures of somatic physiology in the quantitative assessment of sleep could further our understanding of sleep's function as an auto-regulatory, global phenomenon.

  16. Physiological Monitoring in Diving Mammals

    Science.gov (United States)

    2015-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Physiological Monitoring in Diving Mammals Andreas...825-2025 email: andreas.fahlman@tamucc.edu Peter L. Tyack School of Biology Sea Mammal Research Unit Scottish Oceans Institute...OBJECTIVES This project is separated into three aims: Aim 1: Develop a new generation of tags/data logger for marine mammals that will

  17. Nitric oxide: a physiologic messenger.

    Science.gov (United States)

    Lowenstein, C J; Dinerman, J L; Snyder, S H

    1994-02-01

    To review the physiologic role of nitric oxide, an unusual messenger molecule that mediates blood vessel relaxation, neurotransmission, and pathogen suppression. A MEDLINE search of articles published from 1987 to 1993 that addressed nitric oxide and the enzyme that synthesizes it, nitric oxide synthase. Animal and human studies were selected from 3044 articles to analyze the clinical importance of nitric oxide. Descriptions of the structure and function of nitric oxide synthase were selected to show how nitric oxide acts as a biological messenger molecule. Biochemical and physiologic studies were analyzed if the same results were found by three or more independent observers. Two major classes of nitric oxide synthase enzymes produce nitric oxide. The constitutive isoforms found in endothelial cells and neurons release small amounts of nitric oxide for brief periods to signal adjacent cells, whereas the inducible isoform found in macrophages releases large amounts of nitric oxide continuously to eliminate bacteria and parasites. By diffusing into adjacent cells and binding to enzymes that contain iron, nitric oxide plays many important physiologic roles. It regulates blood pressure, transmits signals between neurons, and suppresses pathogens. Excess amounts, however, can damage host cells, causing neurotoxicity during strokes and causing the hypotension associated with sepsis. Nitric oxide is a simple molecule with many physiologic roles in the cardiovascular, neurologic, and immune systems. Although the general principles of nitric oxide synthesis are known, further research is necessary to determine what role it plays in causing disease.

  18. Computational model of cerebral blood flow redistribution during cortical spreading depression

    Science.gov (United States)

    Verisokin, Andrey Y.; Verveyko, Darya V.; Postnov, Dmitry E.

    2016-04-01

    In recent decades modelling studies on cortical spreading depression (CSD) and migraine waves successfully contributed to formation of modern view on these fundamental phenomena of brain physiology. However, due to the extreme complexity of object under study (brain cortex) and the diversity of involved physiological pathways, the development of new mathematical models of CSD is still a very relevant and challenging research problem. In our study we follow the functional modelling approach aimed to map the action of known physiological pathways to the specific nonlinear mechanisms that govern formation and evolution of CSD wave patterns. Specifically, we address the role of cerebral blood flow (CBF) redistribution that is caused by excessive neuronal activity by means of neurovascular coupling and mediates a spatial pattern of oxygen and glucose delivery. This in turn changes the local metabolic status of neural tissue. To build the model we simplify the web of known cell-to-cell interactions within a neurovascular unit by selecting the most relevant ones, such as local neuron-induced elevation of extracellular potassium concentration and biphasic response of arteriole radius. We propose the lumped description of distance-dependent hemodynamic coupling that fits the most recent experimental findings.

  19. Rotating flow

    CERN Document Server

    Childs, Peter R N

    2010-01-01

    Rotating flow is critically important across a wide range of scientific, engineering and product applications, providing design and modeling capability for diverse products such as jet engines, pumps and vacuum cleaners, as well as geophysical flows. Developed over the course of 20 years' research into rotating fluids and associated heat transfer at the University of Sussex Thermo-Fluid Mechanics Research Centre (TFMRC), Rotating Flow is an indispensable reference and resource for all those working within the gas turbine and rotating machinery industries. Traditional fluid and flow dynamics titles offer the essential background but generally include very sparse coverage of rotating flows-which is where this book comes in. Beginning with an accessible introduction to rotating flow, recognized expert Peter Childs takes you through fundamental equations, vorticity and vortices, rotating disc flow, flow around rotating cylinders and flow in rotating cavities, with an introduction to atmospheric and oceanic circul...

  20. Flow theory and MR techniques

    International Nuclear Information System (INIS)

    Listerud, J.; Altas, S.W.; Axel, L.

    1991-01-01

    One of the unique characteristics of magnetic resonance imaging (MRI) is its depiction of flow, even without the administration of intravascular contrast agents. Flow-related phenomena were recognized early in the development of nuclear magnetic resonance, well before imaging techniques were even devised. The appearance of flowing fluid (e.g., blood or CSF) is important to understand for several reasons. First, its signal intensity is quite variable, even in normal physiologic states, so the possibility of misinterpreting normal findings as representing pathologic conditions, such as vascular thrombosis, is reduced if one has a solid conceptualization of the physical basis of flow effects. Second, signal emanating from flowing spins often generates significant artifacts that can obscure anatomy and degrade images, thereby reducing the radiologist's ability to interpret images and identify lesions. The understanding of flow artifacts allows one to recognize them and implement maneuvers to eliminate or compensate for such effects. Third, it has become apparent that the signal information from flow can be exploited to provide previously unavailable physiologic information

  1. Flow visualization

    CERN Document Server

    Merzkirch, Wolfgang

    1974-01-01

    Flow Visualization describes the most widely used methods for visualizing flows. Flow visualization evaluates certain properties of a flow field directly accessible to visual perception. Organized into five chapters, this book first presents the methods that create a visible flow pattern that could be investigated by visual inspection, such as simple dye and density-sensitive visualization methods. It then deals with the application of electron beams and streaming birefringence. Optical methods for compressible flows, hydraulic analogy, and high-speed photography are discussed in other cha

  2. Modelling food-web mediated effects of hydrological variability and environmental flows.

    Science.gov (United States)

    Robson, Barbara J; Lester, Rebecca E; Baldwin, Darren S; Bond, Nicholas R; Drouart, Romain; Rolls, Robert J; Ryder, Darren S; Thompson, Ross M

    2017-11-01

    Environmental flows are designed to enhance aquatic ecosystems through a variety of mechanisms; however, to date most attention has been paid to the effects on habitat quality and life-history triggers, especially for fish and vegetation. The effects of environmental flows on food webs have so far received little attention, despite food-web thinking being fundamental to understanding of river ecosystems. Understanding environmental flows in a food-web context can help scientists and policy-makers better understand and manage outcomes of flow alteration and restoration. In this paper, we consider mechanisms by which flow variability can influence and alter food webs, and place these within a conceptual and numerical modelling framework. We also review the strengths and weaknesses of various approaches to modelling the effects of hydrological management on food webs. Although classic bioenergetic models such as Ecopath with Ecosim capture many of the key features required, other approaches, such as biogeochemical ecosystem modelling, end-to-end modelling, population dynamic models, individual-based models, graph theory models, and stock assessment models are also relevant. In many cases, a combination of approaches will be useful. We identify current challenges and new directions in modelling food-web responses to hydrological variability and environmental flow management. These include better integration of food-web and hydraulic models, taking physiologically-based approaches to food quality effects, and better representation of variations in space and time that may create ecosystem control points. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  3. Post-operative ventricular flow dynamics following atrioventricular valve surgical and device therapies: A review.

    Science.gov (United States)

    Nguyen, Yen Ngoc; Ismail, Munirah; Kabinejadian, Foad; Tay, Edgar Lik Wui; Leo, Hwa Liang

    2018-04-01

    Intra-ventricular flow dynamics has recently emerged as an important evaluation and diagnosis tool in different cardiovascular conditions. The formation of vortex pattern during the cardiac cycle has been suggested to play important epigenetic and energy-modulation roles in cardiac remodelling, adaptations and mal-adaptations. In this new perspective, flow alterations due to different cardiovascular procedures can affect the long-term outcome of those procedures. Especially, repairs and replacements performed on atrioventricular valves are likely to exert direct impact on intra-ventricular flow pattern. In this review, current consensus around the roles of vortex dynamics in cardiac function is discussed. An overview of physiological vortex patterns found in healthy left and right ventricles as well as post-operative ventricular flow phenomenon owing to different atrioventricular valvular procedures are reviewed, followed by the summary of different vortex identification schemes used to characterise intraventricular flow. This paper also emphasises on future research directions towards a comprehensive understanding of intra-cardiac flow and its clinical relevance. The knowledge could encourage more effective pre-operative planning and better outcomes for current clinical practices. Copyright © 2018. Published by Elsevier Ltd.

  4. Human Physiology in an Aquatic Environment.

    Science.gov (United States)

    Pendergast, David R; Moon, Richard E; Krasney, John J; Held, Heather E; Zamparo, Paola

    2015-09-20

    Water covers over 70% of the earth, has varying depths and temperatures and contains much of the earth's resources. Head-out water immersion (HOWI) or submersion at various depths (diving) in water of thermoneutral (TN) temperature elicits profound cardiorespiratory, endocrine, and renal responses. The translocation of blood into the thorax and elevation of plasma volume by autotransfusion of fluid from cells to the vascular compartment lead to increased cardiac stroke volume and output and there is a hyperperfusion of some tissues. Pulmonary artery and capillary hydrostatic pressures increase causing a decline in vital capacity with the potential for pulmonary edema. Atrial stretch and increased arterial pressure cause reflex autonomic responses which result in endocrine changes that return plasma volume and arterial pressure to preimmersion levels. Plasma volume is regulated via a reflex diuresis and natriuresis. Hydrostatic pressure also leads to elastic loading of the chest, increasing work of breathing, energy cost, and thus blood flow to respiratory muscles. Decreases in water temperature in HOWI do not affect the cardiac output compared to TN; however, they influence heart rate and the distribution of muscle and fat blood flow. The reduced muscle blood flow results in a reduced maximal oxygen consumption. The properties of water determine the mechanical load and the physiological responses during exercise in water (e.g. swimming and water based activities). Increased hydrostatic pressure caused by submersion does not affect stroke volume; however, progressive bradycardia decreases cardiac output. During submersion, compressed gas must be breathed which introduces the potential for oxygen toxicity, narcosis due to nitrogen, and tissue and vascular gas bubbles during decompression and after may cause pain in joints and the nervous system. Copyright © 2015 John Wiley & Sons, Inc.

  5. Blood Cell Interactions and Segregation in Flow

    OpenAIRE

    Munn, Lance L.; Dupin, Michael M.

    2008-01-01

    For more than a century, pioneering researchers have been using novel experimental and computational approaches to probe the mysteries of blood flow. Thanks to their efforts, we know that blood cells generally prefer to migrate to the axis of flow, that red and white cells segregate in flow, and that cell deformability and their tendency to reversibly aggregate contribute to the non-Newtonian nature of this unique fluid. All of these properties have beneficial physiological consequences, allo...

  6. Controversial constitutive TSHR activity: patients, physiology, and in vitro characterization.

    Science.gov (United States)

    Huth, S; Jaeschke, H; Schaarschmidt, J; Paschke, R

    2014-06-01

    G protein-coupled receptors constitute a large family of transmembrane receptors, which activate cellular responses by signal transmission and regulation of second messenger metabolism after ligand binding. For several of these receptors it is known that they also signal ligand-independently. The G protein-coupled thyroid stimulating hormone receptor (TSHR) is characterized by a high level of constitutive activity in the wild type state. However, little is known yet concerning the physiological relevance of the constitutive wild type TSHR activity. Certainly, knowledge of the physiological relevance of constitutive wild type receptor activity is necessary to better understand thyroid physiology and it is a prerequisite for the development of better therapies for nonautoimmune hyperthyroidism and thyroid cancer. Based on a literature search regarding all published TSHR mutations, this review covers several mutations which are clearly associated with a hyperthyroidism-phenotype, but interestingly show a lack of constitutive activity determined by in vitro characterization. Possible reasons for the observed discrepancies between clinical phenotypes and in vitro characterization results for constitutive TSHR activity are reviewed. All current in vitro characterization methods for constitutive TSHR mutations are "preliminary attempts" and may well be revised by more comprehensive and even better approaches. However, a standardized approach for the determination of constitutive activity can help to identify TSHR mutations for which the investigation of additional signaling mechanisms would be most interesting to find explanations for the current clinical phenotype/in vitro discrepancies and thereby also define suitable methods to explore the physiological relevance of constitutive wild type TSHR activity. © Georg Thieme Verlag KG Stuttgart · New York.

  7. Physiological parameters for oral delivery and in vitro testing.

    Science.gov (United States)

    Mudie, Deanna M; Amidon, Gordon L; Amidon, Gregory E

    2010-10-04

    Pharmaceutical solid oral dosage forms must undergo dissolution in the intestinal fluids of the gastrointestinal tract before they can be absorbed and reach the systemic circulation. Therefore, dissolution is a critical part of the drug-delivery process. The rate and extent of drug dissolution and absorption depend on the characteristics of the active ingredient as well as properties of the dosage form. Just as importantly, characteristics of the physiological environment such as buffer species, pH, bile salts, gastric emptying rate, intestinal motility, and hydrodynamics can significantly impact dissolution and absorption. While significant progress has been made since 1970 when the first compendial dissolution test was introduced (USP apparatus 1), current dissolution testing does not take full advantage of the extensive physiologic information that is available. For quality control purposes, where the question is one of lot-to-lot consistency in performance, using nonphysiologic test conditions that match drug and dosage form properties with practical dissolution media and apparatus may be appropriate. However, where in vitro-in vivo correlations are desired, it is logical to consider and utilize knowledge of the in vivo condition. This publication critically reviews the literature that is relevant to oral human drug delivery. Physiologically relevant information must serve as a basis for the design of dissolution test methods and systems that are more representative of the human condition. As in vitro methods advance in their physiological relevance, better in vitro-in vivo correlations will be possible. This will, in turn, lead to in vitro systems that can be utilized to more effectively design dosage forms that have improved and more consistent oral bioperformance.

  8. Flow regimes

    International Nuclear Information System (INIS)

    Kh'yuitt, G.

    1980-01-01

    An introduction into the problem of two-phase flows is presented. Flow regimes arizing in two-phase flows are described, and classification of these regimes is given. Structures of vertical and horizontal two-phase flows and a method of their identification using regime maps are considered. The limits of this method application are discussed. The flooding phenomena and phenomena of direction change (flow reversal) of the flow and interrelation of these phenomena as well as transitions from slug regime to churn one and from churn one to annular one in vertical flows are described. Problems of phase transitions and equilibrium are discussed. Flow regimes in tubes where evaporating liquid is running, are described [ru

  9. Physiological pattern of lumbar disc height

    International Nuclear Information System (INIS)

    Biggemann, M.; Frobin, W.; Brinckmann, P.

    1997-01-01

    Purpose of this study is to present a new method of quantifying objectively the height of all discs in lateral radiographs of the lumbar spine and of analysing the normal craniocaudal sequence pattern of lumbar disc heights. Methods: The new parameter is the ventrally measured disc height corrected for the dependence on the angle of lordosis by normalisation to mean angles observed in the erect posture of healthy persons. To eliminate radiographic magnification, the corrected ventral height is related to the mean depth of the cranially adjoining vertebra. In this manner lumbar disc heights were objectively measured in young, mature and healthy persons (146 males and 65 females). The craniocaudal sequence pattern was analysed by mean values from all persons and by height differences of adjoining discs in each individual lumbar spine. Results: Mean normative values demonstrated an increase in disc height between L1/L2 and L4/L5 and a constant or decreasing disc height between L4/L5 and L5/S1. However, this 'physiological sequence of disc height in the statistical mean' was observed in only 36% of normal males and 55% of normal females. Conclusion: The radiological pattern of the 'physiological sequence of lumbar disc height' leads to a relevant portion of false positive pathological results especially at L4/L5. An increase of disc height from L4/L5 to L5/S1 may be normal. The recognition of decreased disc height should be based on an abrupt change in the heights of adjoining discs and not on a deviation from a craniocaudal sequence pattern. (orig.) [de

  10. Historical microbiology, is it relevant in the 21st century?

    Science.gov (United States)

    Robertson, Lesley A

    2015-05-01

    Facsimile microscopes have been used to examine the possibilities of van Leeuwenhoek microscopes with a range of magnifications, particularly to confirm that bacteria can be seen if the microscope is strong enough. The relevance of historical microbiology in education is also illustrated by adapting versions of van Leeuwenhoek's pepper water experiment and Beijerinck's use of bioluminescent bacteria as oxygen probes. These experiments can demonstrate fundamentals such as enrichment and isolation cultures, physiology and experimental planning as well as critical reading of published material. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  11. Flow in Pelton turbines

    OpenAIRE

    Furnes, Kjartan

    2013-01-01

    The flow in Pelton turbines is subsonic, turbulent, multiphase (water, air, and water vapor from cavitation), has high speeds, sharp gradients, free surface and dynamic boundary conditions. A static grid is unsuitable for modeling this mainly due to the turbine wheel and the liquid having a non-stationary relative motion.In recent times, significant progress in CFD simulation has been made, which also is relevant for Pelton turbines.Nevertheless, it is still common to perform costly model tes...

  12. Microdosing: Concept, application and relevance

    Directory of Open Access Journals (Sweden)

    Tushar Tewari

    2010-01-01

    Full Text Available The use of microdose pharmacokinetic studies as an essential tool in drug development is still to catch on. While this approach promises potential cost savings and a quantum leap in efficiencies of the drug development process, major hurdles still need to be overcome before the technique becomes commonplace and part of routine practice. Clear regulations in Europe and the USA have had an enabling effect. The lack of enabling provisions for microdosing studies in Indian regulation, despite low risk and manifest relevance for the local drug development industry, is inconsistent with the country′s aspirations to be among the leaders in pharmaceutical research.

  13. Pulsatile pipe flow transition: Flow waveform effects

    Science.gov (United States)

    Brindise, Melissa C.; Vlachos, Pavlos P.

    2018-01-01

    Although transition is known to exist in various hemodynamic environments, the mechanisms that govern this flow regime and their subsequent effects on biological parameters are not well understood. Previous studies have investigated transition in pulsatile pipe flow using non-physiological sinusoidal waveforms at various Womersley numbers but have produced conflicting results, and multiple input waveform shapes have yet to be explored. In this work, we investigate the effect of the input pulsatile waveform shape on the mechanisms that drive the onset and development of transition using particle image velocimetry, three pulsatile waveforms, and six mean Reynolds numbers. The turbulent kinetic energy budget including dissipation rate, production, and pressure diffusion was computed. The results show that the waveform with a longer deceleration phase duration induced the earliest onset of transition, while the waveform with a longer acceleration period delayed the onset of transition. In accord with the findings of prior studies, for all test cases, turbulence was observed to be produced at the wall and either dissipated or redistributed into the core flow by pressure waves, depending on the mean Reynolds number. Turbulent production increased with increasing temporal velocity gradients until an asymptotic limit was reached. The turbulence dissipation rate was shown to be independent of mean Reynolds number, but a relationship between the temporal gradients of the input velocity waveform and the rate of turbulence dissipation was found. In general, these results demonstrated that the shape of the input pulsatile waveform directly affected the onset and development of transition.

  14. PHYSIOLOGY OF ACID BASE BALANCE

    Directory of Open Access Journals (Sweden)

    Awati

    2014-12-01

    Full Text Available Acid-base, electrolyte, and metabolic disturbances are common in the intensive care unit. Almost all critically ill patients often suffer from compound acid-base and electrolyte disorders. Successful evaluation and management of such patients requires recognition of common patterns (e.g., metabolic acidosis and the ability to dissect one disorder from another. The intensivists needs to identify and correct these condition with the easiest available tools as they are the associated with multiorgan failure. Understanding the elements of normal physiology in these areas is very important so as to diagnose the pathological condition and take adequate measures as early as possible. Arterial blood gas analysis is one such tool for early detection of acid base disorder. Physiology of acid base is complex and here is the attempt to simplify it in our day to day application for the benefit of critically ill patients.

  15. Physiological Studies of Arctic Carnivores.

    Science.gov (United States)

    1982-12-01

    All transmitters were maintained in a cold sterilant ( benzalkonium chloride ) until implanted in a bear. Radio-transmitters for monitoring temperature...body was unknown, particularly during the winter when bears are in dens and there is a generalized reduction in metabolism and other physiological... reduction in core body temperature from summer to winter closely agrees with those reported earlier for bears maintained in captivity under simulated

  16. System Theory and Physiological Processes.

    Science.gov (United States)

    Jones, R W

    1963-05-03

    Engineers and physiologists working together in experimental and theoretical studies predict that the application of system analysis to biological processes will increase understanding of these processes and broaden the base of system theory. Richard W. Jones, professor of electrical engineering at Northwestern University, Evanston, Illinois, and John S. Gray, professor of physiology at Northwestern's Medical School, discuss these developments. Their articles are adapted from addresses delivered in Chicago in November 1962 at the 15th Annual Conference on Engineering in Medicine and Biology.

  17. Human physiological models of insomnia.

    Science.gov (United States)

    Richardson, Gary S

    2007-12-01

    Despite the wide prevalence and important consequences of insomnia, remarkably little is known about its pathophysiology. Available models exist primarily in the psychological domain and derive from the demonstrated efficacy of behavioral treatment approaches to insomnia management. However, these models offer little specific prediction about the anatomic or physiological foundation of chronic primary insomnia. On the other hand, a growing body of data on the physiology of sleep supports a reasonably circumscribed overview of possible pathophysiological mechanisms, as well as the development of physiological models of insomnia to guide future research. As a pragmatic step, these models focus on primary insomnia, as opposed to comorbid insomnias, because the latter is by its nature a much more heterogeneous presentation, reflecting the effects of the distinct comorbid condition. Current understanding of the regulation of sleep and wakefulness in mammalian brain supports four broad candidate areas: 1) disruption of the sleep homeostat; 2) disruption of the circadian clock; 3) disruption of intrinsic systems responsible for the expression of sleep states; or 4) disruption (hyperactivity) of extrinsic systems capable of over-riding normal sleep-wake regulation. This review examines each of the four candidate pathophysiological mechanisms and the available data in support of each. While studies that directly test the viability of each model are not yet available, descriptive data on primary insomnia favor the involvement of dysfunctional extrinsic stress-response systems in the pathology of primary chronic insomnia.

  18. Klismaphilia--a physiological perspective.

    Science.gov (United States)

    Agnew, J

    1982-10-01

    Dr. Joanne Denko coined the work klismaphilia to describe the practices of some of her patients who enjoyed the use of enemas as a sexual stimulant. Since then questions occasionally appear in the professional literature asking about the relationship between enemas and sexual pleasure. This paper considers some of the physiological aspects of the human sexual apparatus that relate to anal sensitivity and explores why klismaphilia can be sexually grafifying. The paper starts with a discussion of the physiological basis for anal sensitivity and anal masturbation in both the human male and the human female. The paper then goes on to relate all this to the sexual sensations received from an enema, and discusses the similarities and differences between all these types of stimulation. Some of the psychological aspects of klismaphilia are also considered in relationship to the physiology involved. The paper concludes with a brief discussion of masked anal masturbation among the population at large. A comprehensive list of references from the literature is given to support these findings.

  19. Metabolism of psilocybin and psilocin: clinical and forensic toxicological relevance.

    Science.gov (United States)

    Dinis-Oliveira, Ricardo Jorge

    2017-02-01

    Psilocybin and psilocin are controlled substances in many countries. These are the two main hallucinogenic compounds of the "magic mushrooms" and both act as agonists or partial agonists at 5-hydroxytryptamine (5-HT) 2A subtype receptors. During the last few years, psilocybin and psilocin have gained therapeutic relevance but considerable physiological variability between individuals that can influence dose-response and toxicological profile has been reported. This review aims to discuss metabolism of psilocybin and psilocin, by presenting all major and minor psychoactive metabolites. Psilocybin is primarily a pro-drug that is dephosphorylated by alkaline phosphatase to active metabolite psilocin. This last is then further metabolized, psilocin-O-glucuronide being the main urinary metabolite with clinical and forensic relevance in diagnosis.

  20. Industrial Relevance of Chromosomal Copy Number Variation in Saccharomyces Yeasts

    Science.gov (United States)

    Gorter de Vries, Arthur R.; Pronk, Jack T.

    2017-01-01

    ABSTRACT Chromosomal copy number variation (CCNV) plays a key role in evolution and health of eukaryotes. The unicellular yeast Saccharomyces cerevisiae is an important model for studying the generation, physiological impact, and evolutionary significance of CCNV. Fundamental studies of this yeast have contributed to an extensive set of methods for analyzing and introducing CCNV. Moreover, these studies provided insight into the balance between negative and positive impacts of CCNV in evolutionary contexts. A growing body of evidence indicates that CCNV not only frequently occurs in industrial strains of Saccharomyces yeasts but also is a key contributor to the diversity of industrially relevant traits. This notion is further supported by the frequent involvement of CCNV in industrially relevant traits acquired during evolutionary engineering. This review describes recent developments in genome sequencing and genome editing techniques and discusses how these offer opportunities to unravel contributions of CCNV in industrial Saccharomyces strains as well as to rationally engineer yeast chromosomal copy numbers and karyotypes. PMID:28341679

  1. In vitro toxicological nanoparticle studies under flow exposure

    Energy Technology Data Exchange (ETDEWEB)

    Sambale, Franziska, E-mail: sambale@iftc.uni-hannover.de; Stahl, Frank; Bahnemann, Detlef; Scheper, Thomas [Gottfried Wilhelm Leibniz University Hanover, Institute for Technical Chemistry (Germany)

    2015-07-15

    The use of nanoparticles is becoming increasingly common in industry and everyday objects. Thus, extensive risk management concerning the potential health risk of nanoparticles is important. Currently, in vitro nanoparticle testing is mainly performed under static culture conditions without any shear stress. However, shear stress is an important biomechanical parameter. Therefore, in this study, a defined physiological flow to different mammalian cell lines such as A549 cells and NIH-3T3 cells has been applied. The effects of zinc oxide and titanium dioxide nanoparticles (TiO{sub 2}-NP), respectively, were investigated under both static and dynamic conditions. Cell viability, cell morphology, and adhesion were proven and compared to the static cell culture. Flow exposure had an impact on the cellular morphology of the cells. NIH-3T3 cells were elongated in the direction of flow and A549 cells exhibited vesicles inside the cells. Zinc oxide nanoparticles reduced the cell viability in the static and in the dynamic culture; however, the dynamic cultures were more sensitive. In the static culture and in the dynamic culture, TiO{sub 2}-NP did not affect cell viability. In conclusion, dynamic culture conditions are important for further in vitro investigations and provide more relevant results than static culture conditions.

  2. In vitro toxicological nanoparticle studies under flow exposure

    International Nuclear Information System (INIS)

    Sambale, Franziska; Stahl, Frank; Bahnemann, Detlef; Scheper, Thomas

    2015-01-01

    The use of nanoparticles is becoming increasingly common in industry and everyday objects. Thus, extensive risk management concerning the potential health risk of nanoparticles is important. Currently, in vitro nanoparticle testing is mainly performed under static culture conditions without any shear stress. However, shear stress is an important biomechanical parameter. Therefore, in this study, a defined physiological flow to different mammalian cell lines such as A549 cells and NIH-3T3 cells has been applied. The effects of zinc oxide and titanium dioxide nanoparticles (TiO 2 -NP), respectively, were investigated under both static and dynamic conditions. Cell viability, cell morphology, and adhesion were proven and compared to the static cell culture. Flow exposure had an impact on the cellular morphology of the cells. NIH-3T3 cells were elongated in the direction of flow and A549 cells exhibited vesicles inside the cells. Zinc oxide nanoparticles reduced the cell viability in the static and in the dynamic culture; however, the dynamic cultures were more sensitive. In the static culture and in the dynamic culture, TiO 2 -NP did not affect cell viability. In conclusion, dynamic culture conditions are important for further in vitro investigations and provide more relevant results than static culture conditions

  3. Characterization of micro-invasive trabecular bypass stents by ex vivo perfusion and computational flow modeling

    Directory of Open Access Journals (Sweden)

    Hunter KS

    2014-03-01

    Full Text Available Kendall S Hunter,1 Todd Fjield,2 Hal Heitzmann,2 Robin Shandas,1 Malik Y Kahook3 1Department of Bioengineering, University of Colorado Denver, Aurora, CO, USA; 2Glaukos Corporation, Laguna Hills, CA, USA; 3University of Colorado Hospital Eye Center, Aurora, CO, USA Abstract: Micro-invasive glaucoma surgery with the Glaukos iStent® or iStent inject® (Glaukos Corporation, Laguna Hills, CA, USA is intended to create a bypass through the trabecular meshwork to Schlemm's canal to improve aqueous outflow through the natural physiologic pathway. While the iStent devices have been evaluated in ex vivo anterior segment models, they have not previously been evaluated in whole eye perfusion models nor characterized by computational fluid dynamics. Intraocular pressure (IOP reduction with the iStent was evaluated in an ex vivo whole human eye perfusion model. Numerical modeling, including computational fluid dynamics, was used to evaluate the flow through the stents over physiologically relevant boundary conditions. In the ex vivo model, a single iStent reduced IOP by 6.0 mmHg from baseline, and addition of a second iStent further lowered IOP by 2.9 mmHg, for a total IOP reduction of 8.9 mmHg. Computational modeling showed that simulated flow through the iStent or iStent inject is smooth and laminar at physiological flow rates. Each stent was computed to have a negligible flow resistance consistent with an expected significant decrease in IOP. The present perfusion results agree with prior clinical and laboratory studies to show that both iStent and iStent inject therapies are potentially titratable, providing clinicians with the opportunity to achieve lower target IOPs by implanting additional stents. Keywords: glaucoma, iStent, trabecular bypass, intraocular pressure, ab-interno, CFD

  4. Designing reliability information flows

    International Nuclear Information System (INIS)

    Petkova, Valia T.; Lu Yuan; Ion, Roxana A.; Sander, Peter C.

    2005-01-01

    It is well-known [Reliab. Eng. Syst. Saf. 75 (2002) 295] that in modern development processes it is essential to have an information flow structure that facilitates fast feedback from product users (customers) to departments at the front end, in particular development and production. As information is only relevant if it is used when taking decisions, this paper presents a guideline for building field feedback information flows that facilitate the decision taking during the product creation and realisation process. The guideline takes into consideration that the type of decisions depends on the span-of-control, therefore following Parsons [Structure and Process in Modern Societies (1990)] the span-of-control is subdivided into the following three levels: strategic, tactic, and executive. The guideline is illustrated with a case in which it is used for analysing the quality of existing field feedback flows

  5. Secondary flow structures under stent-induced perturbations for cardiovascular flow in a curved artery model

    International Nuclear Information System (INIS)

    Glenn, Autumn L.; Bulusu, Kartik V.; Shu Fangjun; Plesniak, Michael W.

    2012-01-01

    Secondary flows within curved arteries with unsteady forcing result from amplified centrifugal instabilities and are expected to be driven by the rapid accelerations and decelerations inherent in physiological waveforms. These secondary flows may also affect the function of curved arteries through pro-atherogenic wall shear stresses, platelet residence time and other vascular response mechanisms. Planar PIV measurements were performed under multi-harmonic non-zero-mean and physiological carotid artery waveforms at various locations in a rigid bent-pipe curved artery model. Results revealed symmetric counter-rotating vortex pairs that developed during the acceleration phases of both multi-harmonic and physiological waveforms. An idealized stent model was placed upstream of the bend, which initiated flow perturbations under physiological inflow conditions. Changes in the secondary flow structures were observed during the systolic deceleration phase (t/T ≈ 0.20–0.50). Proper Orthogonal Decomposition (POD) analysis of the flow morphologies under unsteady conditions indicated similarities in the coherent secondary-flow structures and correlation with phase-averaged velocity fields. A regime map was created that characterizes the kaleidoscope of vortical secondary flows with multiple vortex pairs and interesting secondary flow morphologies. This regime map in the curved artery model was created by plotting the secondary Reynolds number against another dimensionless acceleration-based parameter marking numbered regions of vortex pairs.

  6. Secondary flow structures under stent-induced perturbations for cardiovascular flow in a curved artery model

    Energy Technology Data Exchange (ETDEWEB)

    Glenn, Autumn L.; Bulusu, Kartik V. [Department of Mechanical and Aerospace Engineering, George Washington University, 801 22nd Street, NW., Washington, DC 20052 (United States); Shu Fangjun [Department of Mechanical and Aerospace Engineering, New Mexico State University, MSC 3450, P.O. Box 30001, Las Cruces, NM 88003-8001 (United States); Plesniak, Michael W., E-mail: plesniak@gwu.edu [Department of Mechanical and Aerospace Engineering, George Washington University, 801 22nd Street, NW., Washington, DC 20052 (United States)

    2012-06-15

    Secondary flows within curved arteries with unsteady forcing result from amplified centrifugal instabilities and are expected to be driven by the rapid accelerations and decelerations inherent in physiological waveforms. These secondary flows may also affect the function of curved arteries through pro-atherogenic wall shear stresses, platelet residence time and other vascular response mechanisms. Planar PIV measurements were performed under multi-harmonic non-zero-mean and physiological carotid artery waveforms at various locations in a rigid bent-pipe curved artery model. Results revealed symmetric counter-rotating vortex pairs that developed during the acceleration phases of both multi-harmonic and physiological waveforms. An idealized stent model was placed upstream of the bend, which initiated flow perturbations under physiological inflow conditions. Changes in the secondary flow structures were observed during the systolic deceleration phase (t/T Almost-Equal-To 0.20-0.50). Proper Orthogonal Decomposition (POD) analysis of the flow morphologies under unsteady conditions indicated similarities in the coherent secondary-flow structures and correlation with phase-averaged velocity fields. A regime map was created that characterizes the kaleidoscope of vortical secondary flows with multiple vortex pairs and interesting secondary flow morphologies. This regime map in the curved artery model was created by plotting the secondary Reynolds number against another dimensionless acceleration-based parameter marking numbered regions of vortex pairs.

  7. Other relevant numerical modelling papers

    International Nuclear Information System (INIS)

    Chartier, M.

    1989-01-01

    The ocean modelling is a rapidly evolving science and a large number of results have been published. Several categories of papers are of particular interest for this review: the papers published by the international atomic institutions, such as the NEA (for the CRESP or Subseabed Programs), the IAEA (for example the Safety Series, the Technical Report Series or the TECDOC), and the ICRP, and the papers concerned by more fundamental research, which are published in specific scientific literature. This paper aims to list some of the most relevant publications for the CRESP purposes. It means by no way to be exhaustive, but informative on the incontestable progress recently achieved in that field. One should note that some of these papers are so recent that their final version has not yet been published

  8. Industrial relevance of thermophilic Archaea.

    Science.gov (United States)

    Egorova, Ksenia; Antranikian, Garabed

    2005-12-01

    The dramatic increase of newly isolated extremophilic microorganisms, analysis of their genomes and investigations of their enzymes by academic and industrial laboratories demonstrate the great potential of extremophiles in industrial (white) biotechnology. Enzymes derived from extremophiles (extremozymes) are superior to the traditional catalysts because they can perform industrial processes even under harsh conditions, under which conventional proteins are completely denatured. In particular, enzymes from thermophilic and hyperthermophilic Archaea have industrial relevance. Despite intensive investigations, our knowledge of the structure-function relationships of their enzymes is still limited. Information concerning the molecular properties of their enzymes and genes has to be obtained to be able to understand the mechanisms that are responsible for catalytic activity and stability at the boiling point of water.

  9. The Relevance of Hegel's Logic

    Directory of Open Access Journals (Sweden)

    John W Burbidge

    2007-12-01

    Full Text Available Hegel defines his Logic as the science that thinks about thinking.nbsp; But when we interpret that work as outlining what happens when we reason we are vulnerable to Fregersquo;s charge of psychologism.nbsp; I use Hegelrsquo;s tripartite distinction among understanding, dialectical and speculative reason as operations of pure thought to suggest how thinking can work with objective concepts.nbsp; In the last analysis, however, our ability to move from the subjective contingency of representations and ideas to the pure concepts we think develops from mechanical memory, which separates sign from sense so hat we can focus simply on the latter.nbsp; By becoming aware of the connections that underlie our thinking processes we may be able to both move beyond the abstractions of symbolic logic and clarify what informal logicians call relevance.

  10. 3-Dimensional Physiologic Postural Range of the Mandible: A Computerized-Assisted Technique—A Case Study

    Directory of Open Access Journals (Sweden)

    Todd Shewman

    2013-01-01

    Full Text Available Previous studies demonstrated that while the mandible assumes its resting position in space, antagonistic muscles should assume minimal muscle activity within a spatial range. This zone of mandibular rest has been mapped using physiologic parameters of muscle activity and incisal spatial kinematics. This case study expands on previous research by monitoring incisal and posterior jaw position and includes lateral pterygoid muscle activity, thus allowing for determining the spatial range including additional relevant coordinates and muscle activity. Four positions were evaluated: a maximum physiologic open position, a maximum physiologic closed position, physiologic rest position, and maximum physiologic protrusion position. Within the physiologic zone of rest formed by these 4 positions, the vertical and anterior borders of the envelope of function may be documented for the incisal and posterior mandible in true 3-dimensional fashion to assist the clinician in determining a physiologic interocclusal freeway space and vertical dimension of occlusion. Advantages and limitations are discussed.

  11. Physiology of excitable membranes: proceedings of the 28th International Congress of Physiological Sciences, Budapest, 1980

    National Research Council Canada - National Science Library

    Salánki, J; Meves, H

    1981-01-01

    ... - - - - - - - - - - - - - - - - - - - - - Regulatory Functions of the CNS. Principles of Motion and Organization Regulatory Functions of the CNS. Subsystems Physiology of Non-excitable Cells Physiology...

  12. Importance of amylases for physiological quality in maize seeds

    Directory of Open Access Journals (Sweden)

    Camila Aparecida Lopes

    2017-09-01

    Full Text Available Seed quality is the result of the sum of genetic, physical, physiological and sanitary attributes that affect seed ability to perform vital functions related to germination, vigor, and longevity. The expression of genes associated with physiological quality can be assessed by means of germination and vigor analyses, as well as by transcript and protein analyses. The objective in this work was to review the relevance of amylase group enzymes to the physiological quality of maize seeds. Within this group, α-amylase (1,4-α-D-glucan glucanohydrolase E.C 3.2.1.1 plays an important role in starch hydrolysis, and is responsible for 90% of the amylolytic activity in maize seeds. It is responsible for starch conversion into sugars (e.g., destrin, which is used for embryo growth. β-amylase (1,4-α-D-glucan maltohydrolase E.C 3.2.1.2 catalyzes the release of maltose and dextrins from the non-reducing ends of starch. Research has shown that amylase enzymes are directly linked to physiological quality of maize seeds. Alpha- and beta-amylases are mainly involved in the germination process and seed heterosis, and can also be used as molecular markers associated with seed tolerance for drying.

  13. Biological properties of extracellular vesicles and their physiological functions

    Science.gov (United States)

    Yáñez-Mó, María; Siljander, Pia R.-M.; Andreu, Zoraida; Zavec, Apolonija Bedina; Borràs, Francesc E.; Buzas, Edit I.; Buzas, Krisztina; Casal, Enriqueta; Cappello, Francesco; Carvalho, Joana; Colás, Eva; Silva, Anabela Cordeiro-da; Fais, Stefano; Falcon-Perez, Juan M.; Ghobrial, Irene M.; Giebel, Bernd; Gimona, Mario; Graner, Michael; Gursel, Ihsan; Gursel, Mayda; Heegaard, Niels H. H.; Hendrix, An; Kierulf, Peter; Kokubun, Katsutoshi; Kosanovic, Maja; Kralj-Iglic, Veronika; Krämer-Albers, Eva-Maria; Laitinen, Saara; Lässer, Cecilia; Lener, Thomas; Ligeti, Erzsébet; Linē, Aija; Lipps, Georg; Llorente, Alicia; Lötvall, Jan; Manček-Keber, Mateja; Marcilla, Antonio; Mittelbrunn, Maria; Nazarenko, Irina; Hoen, Esther N.M. Nolte-‘t; Nyman, Tuula A.; O'Driscoll, Lorraine; Olivan, Mireia; Oliveira, Carla; Pállinger, Éva; del Portillo, Hernando A.; Reventós, Jaume; Rigau, Marina; Rohde, Eva; Sammar, Marei; Sánchez-Madrid, Francisco; Santarém, N.; Schallmoser, Katharina; Ostenfeld, Marie Stampe; Stoorvogel, Willem; Stukelj, Roman; Van der Grein, Susanne G.; Vasconcelos, M. Helena; Wauben, Marca H. M.; De Wever, Olivier

    2015-01-01

    In the past decade, extracellular vesicles (EVs) have been recognized as potent vehicles of intercellular communication, both in prokaryotes and eukaryotes. This is due to their capacity to transfer proteins, lipids and nucleic acids, thereby influencing various physiological and pathological functions of both recipient and parent cells. While intensive investigation has targeted the role of EVs in different pathological processes, for example, in cancer and autoimmune diseases, the EV-mediated maintenance of homeostasis and the regulation of physiological functions have remained less explored. Here, we provide a comprehensive overview of the current understanding of the physiological roles of EVs, which has been written by crowd-sourcing, drawing on the unique EV expertise of academia-based scientists, clinicians and industry based in 27 European countries, the United States and Australia. This review is intended to be of relevance to both researchers already working on EV biology and to newcomers who will encounter this universal cell biological system. Therefore, here we address the molecular contents and functions of EVs in various tissues and body fluids from cell systems to organs. We also review the physiological mechanisms of EVs in bacteria, lower eukaryotes and plants to highlight the functional uniformity of this emerging communication system. PMID:25979354

  14. Biological properties of extracellular vesicles and their physiological functions

    Directory of Open Access Journals (Sweden)

    María Yáñez-Mó

    2015-05-01

    Full Text Available In the past decade, extracellular vesicles (EVs have been recognized as potent vehicles of intercellular communication, both in prokaryotes and eukaryotes. This is due to their capacity to transfer proteins, lipids and nucleic acids, thereby influencing various physiological and pathological functions of both recipient and parent cells. While intensive investigation has targeted the role of EVs in different pathological processes, for example, in cancer and autoimmune diseases, the EV-mediated maintenance of homeostasis and the regulation of physiological functions have remained less explored. Here, we provide a comprehensive overview of the current understanding of the physiological roles of EVs, which has been written by crowd-sourcing, drawing on the unique EV expertise of academia-based scientists, clinicians and industry based in 27 European countries, the United States and Australia. This review is intended to be of relevance to both researchers already working on EV biology and to newcomers who will encounter this universal cell biological system. Therefore, here we address the molecular contents and functions of EVs in various tissues and body fluids from cell systems to organs. We also review the physiological mechanisms of EVs in bacteria, lower eukaryotes and plants to highlight the functional uniformity of this emerging communication system.

  15. Towards Individualized Physiology Lecturing in Africa

    African Journals Online (AJOL)

    Dr Olaleye Samuel

    1 (1): 13 - 16. Journal of African Association of Physiological Sciences ... import from validated text format question series and seamless use of any computer program or internet .... Silverthorn D U, Human Physiology, an Integrated. Approach ...

  16. Nobel Prize in Physiology or Medicine

    Science.gov (United States)

    ... Educational - Medicine Prize Related The Nobel Prize in Physiology or Medicine has been awarded to people and ... this page MLA style: "The Nobel Prize in Physiology or Medicine – Educational". Nobelprize.org. Nobel Media ...

  17. Physiological determinants of human acute hypoxia tolerance.

    Science.gov (United States)

    2013-11-01

    AbstractIntroduction. We investigated possible physiological determinants of variability in hypoxia tolerance in subjects given a 5-minute normobaric exposure to 25,000 ft equivalent. Physiological tolerance to hypoxia was defined as the magnitude of...

  18. Archives: Nigerian Journal of Physiological Sciences

    African Journals Online (AJOL)

    Items 1 - 19 of 19 ... Archives: Nigerian Journal of Physiological Sciences. Journal Home > Archives: Nigerian Journal of Physiological Sciences. Log in or Register to get access to full text downloads.

  19. Physiology of High-Altitude Acclimatization

    Indian Academy of Sciences (India)

    Author Affiliations. Sonam Chawla1 Shweta Saxena2. Defence Institute of Physiology and Allied Sciences, Delhi; Experimental Biology Division Defence Institute of Physiology and Allied Sciences Defence Research and Development Organisation Lucknow Road, Timarpur Delhi 110054 ...

  20. Physiological Parameters Database for Older Adults

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Physiological Parameters Database for Older Adults is available for download and contains physiological parameters values for healthy older human adults (age 60...

  1. A mathematical model of coronary blood flow control: simulation of patient-specific three-dimensional hemodynamics during exercise

    Science.gov (United States)

    Lau, Kevin D.; Asrress, Kaleab N.; Redwood, Simon R.; Figueroa, C. Alberto

    2016-01-01

    This work presents a mathematical model of the metabolic feedback and adrenergic feedforward control of coronary blood flow that occur during variations in the cardiac workload. It is based on the physiological observations that coronary blood flow closely follows myocardial oxygen demand, that myocardial oxygen debts are repaid, and that control oscillations occur when the system is perturbed and so are phenomenological in nature. Using clinical data, we demonstrate that the model can provide patient-specific estimates of coronary blood flow changes between rest and exercise, requiring only the patient's heart rate and peak aortic pressure as input. The model can be used in zero-dimensional lumped parameter network studies or as a boundary condition for three-dimensional multidomain Navier-Stokes blood flow simulations. For the first time, this model provides feedback control of the coronary vascular resistance, which can be used to enhance the physiological accuracy of any hemodynamic simulation, which includes both a heart model and coronary arteries. This has particular relevance to patient-specific simulation for which heart rate and aortic pressure recordings are available. In addition to providing a simulation tool, under our assumptions, the derivation of our model shows that β-feedforward control of the coronary microvascular resistance is a mathematical necessity and that the metabolic feedback control must be dependent on two error signals: the historical myocardial oxygen debt, and the instantaneous myocardial oxygen deficit. PMID:26945076

  2. Spaceflight and Neurosurgery: A Comprehensive Review of the Relevant Literature.

    Science.gov (United States)

    Swinney, Christian C; Allison, Zain

    2018-01-01

    Spaceflight and the associated gravitational fluctuations may impact various components of the central nervous system. These include changes in intracranial pressure, the spine, and neurocognitive performance. The implications of altered astronaut performance on critical spaceflight missions are potentially significant. The current body of research on this important topic is extremely limited, and a comprehensive review has not been published. Herein, the authors address this notable gap, as well as the role of the neurosurgeon in optimizing potential diagnostic and therapeutic modalities. A literature search was conducted using the PubMed, EMBASE, and Google Scholar databases, with no time constraints. Significant manuscripts on physiologic changes associated with spaceflight and microgravity were identified and reviewed. Manifestations were separated into 1 of 3 general categories, including changes in intracranial pressure, the spine, and neurocognitive performance. A comprehensive literature review yielded 27 studies with direct relevance to the impact of microgravity and spaceflight on nervous system physiology. This included 7 studies related to intracranial pressure fluctuations, 17 related to changes in the spinal column, and 3 related to neurocognitive change. The microgravity environment encountered during spaceflight impacts intracranial physiology. This includes changes in intracranial pressure, the spinal column, and neurocognitive performance. Herein, we present a systematic review of the published literature on this issue. Neurosurgeons should have a key role in the continued study of this important topic, contributing to both diagnostic and therapeutic understanding. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Shape oscillations of elastic particles in shear flow.

    Science.gov (United States)

    Subramaniam, Dhananjay Radhakrishnan; Gee, David J

    2016-09-01

    Particle suspensions are common to biological fluid flows; for example, flow of red- and white-blood cells, and platelets. In medical technology, current and proposed methods for drug delivery use membrane-bounded liquid capsules for transport via the microcirculation. In this paper, we consider a 3D linear elastic particle inserted into a Newtonian fluid and investigate the time-dependent deformation using a numerical simulation. Specifically, a boundary element technique is used to investigate the motion and deformation of initially spherical or spheroidal particles in bounded linear shear flow. The resulting deformed shapes reveal a steady-state profile that exhibits a 'tank-treading' motion for initially spherical particles. Wall effects on particle trajectory are seen to include a modified Jeffrey׳s orbit for spheroidal inclusions with a period that varies inversely with the strength of the shear flow. Alternately, spheroidal inclusions may exhibit either a 'tumbling' or 'trembling' motion depending on the initial particle aspect ratio and the capillary number (i.e., ratio of fluid shear to elastic restoring force). We find for a capillary number of 0.1, a tumbling mode transitions to a trembling mode at an aspect ratio of 0.87 (approx.), while for a capillary number of 0.2, this transition takes place at a lower aspect ratio. These oscillatory modes are consistent with experimental observations involving similarly shaped vesicles and thus serves to validate the use of a simple elastic constitutive model to perform relevant physiological flow calculations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Bengt Saltin and exercise physiology: a perspective.

    Science.gov (United States)

    Joyner, Michael J

    2017-01-01

    This perspective highlights some of the key contributions of Professor Bengt Saltin (1935-2014) to exercise physiology. The emergence of exercise physiology from work physiology as his career began is discussed as are his contributions in a number of areas. Saltin's open and question-based style of leadership is a model for the future of our field.

  5. Lacrimal system physiology: radioisotope study

    International Nuclear Information System (INIS)

    De Rossi, G.; Salvatori, M.; Focosi, F.; Dickmann, A.

    1982-01-01

    Lacrimal scintigraphy was used to illustrate the physiology of the lacrimal drainage system in 37 normal patients. Sup(99m)Tc-pertechnetate was dropped on to the conjunctive near the lateral chantus and serial images were displayed dynamically on a video display. It was concluded that this technique provides a very sensitive and reproducible test of the functional status of nasolacrimal drainage along with a graphic documentation at any given time and thus could be extremely useful in the diagnosis of lacrimal pathology. (U.K.)

  6. Chemostat Culture for Yeast Physiology.

    Science.gov (United States)

    Kerr, Emily O; Dunham, Maitreya J

    2017-07-05

    The use of chemostat culture facilitates the careful comparison of different yeast strains growing in well-defined conditions. Variations in physiology can be measured by examining gene expression, metabolite levels, protein content, and cell morphology. In this protocol, we show how a combination of sample types can be collected during harvest from a single 20-mL chemostat in a ministat array, with special attention to coordinating the handling of the most time-sensitive sample types. © 2017 Cold Spring Harbor Laboratory Press.

  7. Identifying and quantifying main components of physiological noise in functional near infrared spectroscopy on prefrontal cortex

    Directory of Open Access Journals (Sweden)

    Evgeniya eKirilina

    2013-12-01

    Full Text Available Functional Near-Infrared Spectroscopy (fNIRS is a promising method to study functional organization of the prefrontal cortex. However, in order to realize the high potential of fNIRS, effective discrimination between physiological noise originating from forehead skin haemodynamic and cerebral signals is required. Main sources of physiological noise are global and local blood flow regulation processes on multiple time scales. The goal of the present study was to identify the main physiological noise contributions in fNIRS forehead signals and to develop a method for physiological de-noising of fNIRS data. To achieve this goal we combined concurrent time-domain fNIRS and peripheral physiology recordings with wavelet coherence analysis. Depth selectivity was achieved by analyzing moments of photon time-of-flight distributions provided by time-domain fNIRS. Simultaneously, mean arterial blood pressure (MAP, heart rate (HR, and skin blood flow (SBF on the forehead were recorded. Wavelet coherence analysis was employed to quantify the impact of physiological processes on fNIRS signals separately for different time scales. We identified three main processes contributing to physiological noise in fNIRS signals on the forehead. The first process with the period of about 3 s is induced by respiration. The second process is highly correlated with time lagged MAP and HR fluctuations with a period of about 10 s often referred as Mayer waves. The third process is local regulation of the facial skin blood flow time locked to the task-evoked fNIRS signals. All processes affect oxygenated haemoglobin concentration more strongly than that of deoxygenated haemoglobin. Based on these results we developed a set of physiological regressors, which were used for physiological de-noising of fNIRS signals. Our results demonstrate that proposed de-noising method can significantly improve the sensitivity of fNIRS to cerebral signals.

  8. Physiological Characterization of Fungal Inoculum for Biotechnological Remediation of Soils

    Directory of Open Access Journals (Sweden)

    Nara Ballaminut

    2014-08-01

    Full Text Available The aim of this work was to study the bioremediating potential of Lentinus crinitus CCIBt2611 according to the physiological condition of the inoculum. Inoculum was prepared using sugarcane ground husk (C:N 90, at several physiological ages and applied in soil contaminated with pentachlorophenol. The inoculum's potential was assessed by evaluating the mycelium's vigor at soil's colonization, determination of peroxidase and phenoloxidase activities, in vitro degradation of Remazol Brilliant Blue R and in vivo degradation of pentachlorophenol. The results showed that the assessed parameters were relevant to identify the quality of the inoculum. For L. crinitus, 10 day old inoculum showed good soil-colonization speed with significant enzymatic activities, indicating the role of Manganese-dependent peroxidase and laccase in degradation, and efficient degradation of pentachlorophenol.

  9. Flow visualization

    International Nuclear Information System (INIS)

    Weinstein, L.M.

    1991-01-01

    Flow visualization techniques are reviewed, with particular attention given to those applicable to liquid helium flows. Three techniques capable of obtaining qualitative and quantitative measurements of complex 3D flow fields are discussed including focusing schlieren, particle image volocimetry, and holocinematography (HCV). It is concluded that the HCV appears to be uniquely capable of obtaining full time-varying, 3D velocity field data, but is limited to the low speeds typical of liquid helium facilities. 8 refs

  10. Contactless physiological signals extraction based on skin color magnification

    Science.gov (United States)

    Suh, Kun Ha; Lee, Eui Chul

    2017-11-01

    Although the human visual system is not sufficiently sensitive to perceive blood circulation, blood flow caused by cardiac activity makes slight changes on human skin surfaces. With advances in imaging technology, it has become possible to capture these changes through digital cameras. However, it is difficult to obtain clear physiological signals from such changes due to its fineness and noise factors, such as motion artifacts and camera sensing disturbances. We propose a method for extracting physiological signals with improved quality from skin colored-videos recorded with a remote RGB camera. The results showed that our skin color magnification method reveals the hidden physiological components remarkably in the time-series signal. A Korea Food and Drug Administration-approved heart rate monitor was used for verifying the resulting signal synchronized with the actual cardiac pulse, and comparisons of signal peaks showed correlation coefficients of almost 1.0. In particular, our method can be an effective preprocessing before applying additional postfiltering techniques to improve accuracy in image-based physiological signal extractions.

  11. A model for investigating the control of muscle blood flow: the masseteric artery in conscious rabbits

    International Nuclear Information System (INIS)

    Roatta, S; Mohammed, M; Turturici, M; Milano, L; Passatore, M

    2010-01-01

    The complex interplay of neural, metabolic, myogenic and mechanical mechanisms that regulate blood flow in skeletal muscle (MBF) is still incompletely understood. For the first time, a method is presented for high time-resolution recording of MBF from a purely muscular artery in physiological conditions. Ultrasound perivascular flow probes were implanted (n = 15) mono- or bilaterally around the masseteric branch of the facial artery in nine rabbits and tested up to 16 days after implant. Reliable and stable recordings were achieved in 50% of implants. Blood flow was observed to increase from a resting level of 0.2–0.3 ml min −1 up to 4.0–6.0 ml min −1 during spontaneous masticatory activity. In addition, within single masticatory cycles marked back flow transients could be observed (peak flow = −10 ml min −1 ) during powerful masticatory strokes but not during mild mastication. The possibility of (1) surgically removing the sympathetic supply to the relevant vascular bed and of (2) bilaterally monitoring the perfusion of masseter muscles thus allowing to use one side as control side for different types of interventions makes this model a useful tool for disentangling the different mechanisms involved in the control of MBF. (note)

  12. Flow regimes

    International Nuclear Information System (INIS)

    Liles, D.R.

    1982-01-01

    Internal boundaries in multiphase flow greatly complicate fluid-dynamic and heat-transfer descriptions. Different flow regimes or topological configurations can have radically dissimilar interfacial and wall mass, momentum, and energy exchanges. To model the flow dynamics properly requires estimates of these rates. In this paper the common flow regimes for gas-liquid systems are defined and the techniques used to estimate the extent of a particular regime are described. Also, the current computer-code procedures are delineated and introduce a potentially better method is introduced

  13. Vygotsky's Crisis: Argument, context, relevance.

    Science.gov (United States)

    Hyman, Ludmila

    2012-06-01

    Vygotsky's The Historical Significance of the Crisis in Psychology (1926-1927) is an important text in the history and philosophy of psychology that has only become available to scholars in 1982 in Russian, and in 1997 in English. The goal of this paper is to introduce Vygotsky's conception of psychology to a wider audience. I argue that Vygotsky's argument about the "crisis" in psychology and its resolution can be fully understood only in the context of his social and political thinking. Vygotsky shared the enthusiasm, widespread among Russian leftist intelligentsia in the 1920s, that Soviet society had launched an unprecedented social experiment: The socialist revolution opened the way for establishing social conditions that would let the individual flourish. For Vygotsky, this meant that "a new man" of the future would become "the first and only species in biology that would create itself." He envisioned psychology as a science that would serve this humanist teleology. I propose that The Crisis is relevant today insofar as it helps us define a fundamental problem: How can we systematically account for the development of knowledge in psychology? I evaluate how Vygotsky addresses this problem as a historian of the crisis. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Relevance of equilibrium in multifragmentation

    International Nuclear Information System (INIS)

    Furuta, Takuya; Ono, Akira

    2009-01-01

    The relevance of equilibrium in a multifragmentation reaction of very central 40 Ca + 40 Ca collisions at 35 MeV/nucleon is investigated by using simulations of antisymmetrized molecular dynamics (AMD). Two types of ensembles are compared. One is the reaction ensemble of the states at each reaction time t in collision events simulated by AMD, and the other is the equilibrium ensemble prepared by solving the AMD equation of motion for a many-nucleon system confined in a container for a long time. The comparison of the ensembles is performed for the fragment charge distribution and the excitation energies. Our calculations show that there exists an equilibrium ensemble that well reproduces the reaction ensemble at each reaction time t for the investigated period 80≤t≤300 fm/c. However, there are some other observables that show discrepancies between the reaction and equilibrium ensembles. These may be interpreted as dynamical effects in the reaction. The usual static equilibrium at each instant is not realized since any equilibrium ensemble with the same volume as that of the reaction system cannot reproduce the fragment observables

  15. Cardiovascular transition at birth: a physiological sequence.

    Science.gov (United States)

    Hooper, Stuart B; Te Pas, Arjan B; Lang, Justin; van Vonderen, Jeroen J; Roehr, Charles Christoph; Kluckow, Martin; Gill, Andrew W; Wallace, Euan M; Polglase, Graeme R

    2015-05-01

    The transition to newborn life at birth involves major cardiovascular changes that are triggered by lung aeration. These include a large increase in pulmonary blood flow (PBF), which is required for pulmonary gas exchange and to replace umbilical venous return as the source of preload for the left heart. Clamping the umbilical cord before PBF increases reduces venous return and preload for the left heart and thereby reduces cardiac output. Thus, if ventilation onset is delayed following cord clamping, the infant is at risk of superimposing an ischemic insult, due to low cardiac output, on top of an asphyxic insult. Much debate has centered on the timing of cord clamping at birth, focusing mainly on the potential for a time-dependent placental to infant blood transfusion. This has prompted recommendations for delayed cord clamping for a set time after birth in infants not requiring resuscitation. However, recent evidence indicates that ventilation onset before cord clamping mitigates the adverse cardiovascular consequences caused by immediate cord clamping. This indicates that the timing of cord clamping should be based on the infant's physiology rather than an arbitrary period of time and that delayed cord clamping may be of greatest benefit to apneic infants.

  16. Physiologically Based Pharmacokinetic Modeling of Therapeutic Proteins.

    Science.gov (United States)

    Wong, Harvey; Chow, Timothy W

    2017-09-01

    Biologics or therapeutic proteins are becoming increasingly important as treatments for disease. The most common class of biologics are monoclonal antibodies (mAbs). Recently, there has been an increase in the use of physiologically based pharmacokinetic (PBPK) modeling in the pharmaceutical industry in drug development. We review PBPK models for therapeutic proteins with an emphasis on mAbs. Due to their size and similarity to endogenous antibodies, there are distinct differences between PBPK models for small molecules and mAbs. The high-level organization of a typical mAb PBPK model consists of a whole-body PBPK model with organ compartments interconnected by both blood and lymph flows. The whole-body PBPK model is coupled with tissue-level submodels used to describe key mechanisms governing mAb disposition including tissue efflux via the lymphatic system, elimination by catabolism, protection from catabolism binding to the neonatal Fc (FcRn) receptor, and nonlinear binding to specific pharmacological targets of interest. The use of PBPK modeling in the development of therapeutic proteins is still in its infancy. Further application of PBPK modeling for therapeutic proteins will help to define its developing role in drug discovery and development. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  17. Physiological Effects of Touching Wood

    Directory of Open Access Journals (Sweden)

    Harumi Ikei

    2017-07-01

    Full Text Available This study aimed to clarify the physiological effects of touching wood with the palm, in comparison with touching other materials on brain activity and autonomic nervous activity. Eighteen female university students (mean age, 21.7  ±  1.6 years participated in the study. As an indicator of brain activity, oxyhemoglobin (oxy-Hb concentrations were measured in the left/right prefrontal cortex using near-infrared time-resolved spectroscopy. Heart rate variability (HRV was used as an indicator of autonomic nervous activity. The high-frequency (HF component of HRV, which reflected parasympathetic nervous activity, and the low-frequency (LF/HF ratio, which reflected sympathetic nervous activity, were measured. Plates of uncoated white oak, marble, tile, and stainless steel were used as tactile stimuli. After sitting at rest with their eyes closed, participants touched the materials for 90 s. As a result, tactile stimulation with white oak significantly (1 decreased the oxy-Hb concentration in the left/right prefrontal cortex relative to marble, tile, and stainless steel and (2 increased ln(HF-reflected parasympathetic nervous activity relative to marble and stainless steel. In conclusion, our study revealed that touching wood with the palm calms prefrontal cortex activity and induces parasympathetic nervous activity more than other materials, thereby inducing physiological relaxation.

  18. Physiological aspects of forest disease

    International Nuclear Information System (INIS)

    Ziegler, H.

    1986-01-01

    Many kinds of forest disease having the most varied causes are currently classified as 'forest die-back'. These include for one part diseases of obvious etiology: infectious diseases, damage from frost and drought, as well as harmful effects of defined air pollutants from known sources. But apart from this, a fast growing tendency is noted for extensive damage to appear whose origin is not yet clearly elucidated and which are probably the result of many factors, in other words, which can be termed as 'chain disease'. A striking fact is that any scientist who has so far attributed that last-mentioned disease condition of forests to any single decisive cause, has chosen one from his own specific scientific field. Physiologic-biochemical analysis of the damage symptoms is impaired by the fact that trees are, for obvious biological reasons, difficult objects for providing precise data. Yet reliable statements can be made on the paths by which wet and dry depositions penetrate into the plant organs, the penetration of pollutants into the cell, their points of attack in cells and tissue (above all photosynthesis, material transport, and hormone balance), and their influence on the correlations between the individual organs. Particular attention should be paid to possible or indirect effects on the mycorrhiza of forest trees, i.e. on the symbiosis between roots and fungi. The physiologic-biochemical investigations and considerations reported provide circumstantial evidence, but no proof regarding the causes hitherto unexplained. (orig.) [de

  19. Environmental Physiology and Diving Medicine

    Directory of Open Access Journals (Sweden)

    Gerardo Bosco

    2018-02-01

    Full Text Available Man’s experience and exploration of the underwater environment has been recorded from ancient times and today encompasses large sections of the population for sport enjoyment, recreational and commercial purpose, as well as military strategic goals. Knowledge, respect and maintenance of the underwater world is an essential development for our future and the knowledge acquired over the last few dozen years will change rapidly in the near future with plans to establish secure habitats with specific long-term goals of exploration, maintenance and survival. This summary will illustrate briefly the physiological changes induced by immersion, swimming, breath-hold diving and exploring while using special equipment in the water. Cardiac, circulatory and pulmonary vascular adaptation and the pathophysiology of novel syndromes have been demonstrated, which will allow selection of individual characteristics in order to succeed in various environments. Training and treatment for these new microenvironments will be suggested with description of successful pioneers in this field. This is a summary of the physiology and the present status of pathology and therapy for the field.

  20. Physiological measures of vaginal vasocongestion

    NARCIS (Netherlands)

    Laan, E.; Everaerd, W.

    1998-01-01

    This paper reviews reliability, specificity, and practical applicability of the two most promising and widely used methods for measuring blood flow within the vagina: the oxygenation-temperature method and vaginal photoplethysmography. It was concluded that the oxygenation-temperature method and

  1. Research as if relevance mattered

    Energy Technology Data Exchange (ETDEWEB)

    Ziman, J [University of Bristol (United Kingdom)

    1978-12-15

    The agenda of next year's UN Conference on Science and Technology for Development (UNCSTD) is all intellectual abstractions and institutional frameworks. It has no words for the people through whom science and technology will flow. The primary resource for development is skilled engineers, doctors, agriculturalists and other technically qualified people to carry out a multitude of constructive tasks. The training and appropriate employment of such people should be a major theme of the conference. Technical training is education in what is already known, research is the generation of new knowledge. The research scientist is an indispensable person in the development process. But what exactly is his role? The introduction of advanced science into the less developed countries (LDCs) has disappointed many high hopes, especially among the scientists themselves. Not only is their research hobbled by poverty of facilities, geographical isolation, social incomprehension and political harassment, they are uneasily aware that they have a negligible influence on the welfare of their fellow countrymen, and live largely by promises of vague benefits that are unlikely to be fulfilled.

  2. Research as if relevance mattered

    International Nuclear Information System (INIS)

    Ziman, J.

    1978-01-01

    The agenda of next year's UN Conference on Science and Technology for Development (UNCSTD) is all intellectual abstractions and institutional frameworks. It has no words for the people through whom science and technology will flow. The primary resource for development is skilled engineers, doctors, agriculturalists and other technically qualified people to carry out a multitude of constructive tasks. The training and appropriate employment of such people should be a major theme of the conference. Technical training is education in what is already known, research is the generation of new knowledge. The research scientist is an indispensable person in the development process. But what exactly is his role? The introduction of advanced science into the less developed countries (LDCs) has disappointed many high hopes, especially among the scientists themselves. Not only is their research hobbled by poverty of facilities, geographical isolation, social incomprehension and political harassment, they are uneasily aware that they have a negligible influence on the welfare of their fellow countrymen, and live largely by promises of vague benefits that are unlikely to be fulfilled

  3. Physiologically guided approach to characterizing respiratory motion

    International Nuclear Information System (INIS)

    White, Benjamin M.; Lamb, James M.; Low, Daniel A.; Zhao, Tianyu; Bradley, Jeffrey D.

    2013-01-01

    Type 1 and Type 2 patients was found to be statistically significant at the 1% significance level. Three patients did not display a breathing stability curve that could be classified as Type 1 or Type 2 due to chaotic breathing patterns. These patients were classified as Type 3 patients. Conclusions: Based on an observed volume-flow curve pattern, the cohort of 50 patients was divided into three categories called Type 1, Type 2, and Type 3. There were statistically significant differences in breathing characteristics between Type 1 and Type 2 patients. The use of volume-flow curves to classify patients has been demonstrated as a physiological characterization metric that has the potential to optimize gating windows in radiation therapy

  4. Network Physiology: How Organ Systems Dynamically Interact.

    Science.gov (United States)

    Bartsch, Ronny P; Liu, Kang K L; Bashan, Amir; Ivanov, Plamen Ch

    2015-01-01

    We systematically study how diverse physiologic systems in the human organism dynamically interact and collectively behave to produce distinct physiologic states and functions. This is a fundamental question in the new interdisciplinary field of Network Physiology, and has not been previously explored. Introducing the novel concept of Time Delay Stability (TDS), we develop a computational approach to identify and quantify networks of physiologic interactions from long-term continuous, multi-channel physiological recordings. We also develop a physiologically-motivated visualization framework to map networks of dynamical organ interactions to graphical objects encoded with information about the coupling strength of network links quantified using the TDS measure. Applying a system-wide integrative approach, we identify distinct patterns in the network structure of organ interactions, as well as the frequency bands through which these interactions are mediated. We establish first maps representing physiologic organ network interactions and discover basic rules underlying the complex hierarchical reorganization in physiologic networks with transitions across physiologic states. Our findings demonstrate a direct association between network topology and physiologic function, and provide new insights into understanding how health and distinct physiologic states emerge from networked interactions among nonlinear multi-component complex systems. The presented here investigations are initial steps in building a first atlas of dynamic interactions among organ systems.

  5. Network Physiology: How Organ Systems Dynamically Interact

    Science.gov (United States)

    Bartsch, Ronny P.; Liu, Kang K. L.; Bashan, Amir; Ivanov, Plamen Ch.

    2015-01-01

    We systematically study how diverse physiologic systems in the human organism dynamically interact and collectively behave to produce distinct physiologic states and functions. This is a fundamental question in the new interdisciplinary field of Network Physiology, and has not been previously explored. Introducing the novel concept of Time Delay Stability (TDS), we develop a computational approach to identify and quantify networks of physiologic interactions from long-term continuous, multi-channel physiological recordings. We also develop a physiologically-motivated visualization framework to map networks of dynamical organ interactions to graphical objects encoded with information about the coupling strength of network links quantified using the TDS measure. Applying a system-wide integrative approach, we identify distinct patterns in the network structure of organ interactions, as well as the frequency bands through which these interactions are mediated. We establish first maps representing physiologic organ network interactions and discover basic rules underlying the complex hierarchical reorganization in physiologic networks with transitions across physiologic states. Our findings demonstrate a direct association between network topology and physiologic function, and provide new insights into understanding how health and distinct physiologic states emerge from networked interactions among nonlinear multi-component complex systems. The presented here investigations are initial steps in building a first atlas of dynamic interactions among organ systems. PMID:26555073

  6. Statistical significance versus clinical relevance.

    Science.gov (United States)

    van Rijn, Marieke H C; Bech, Anneke; Bouyer, Jean; van den Brand, Jan A J G

    2017-04-01

    In March this year, the American Statistical Association (ASA) posted a statement on the correct use of P-values, in response to a growing concern that the P-value is commonly misused and misinterpreted. We aim to translate these warnings given by the ASA into a language more easily understood by clinicians and researchers without a deep background in statistics. Moreover, we intend to illustrate the limitations of P-values, even when used and interpreted correctly, and bring more attention to the clinical relevance of study findings using two recently reported studies as examples. We argue that P-values are often misinterpreted. A common mistake is saying that P < 0.05 means that the null hypothesis is false, and P ≥0.05 means that the null hypothesis is true. The correct interpretation of a P-value of 0.05 is that if the null hypothesis were indeed true, a similar or more extreme result would occur 5% of the times upon repeating the study in a similar sample. In other words, the P-value informs about the likelihood of the data given the null hypothesis and not the other way around. A possible alternative related to the P-value is the confidence interval (CI). It provides more information on the magnitude of an effect and the imprecision with which that effect was estimated. However, there is no magic bullet to replace P-values and stop erroneous interpretation of scientific results. Scientists and readers alike should make themselves familiar with the correct, nuanced interpretation of statistical tests, P-values and CIs. © The Author 2017. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

  7. Impact of enhanced flow on the flow system and wastewater ...

    African Journals Online (AJOL)

    user

    was used to estimate the impact of the excess flow on sewage-fed wetlands. Two neural network ... 33-2414-6979. The United Nations Economic and Social Development ...... developed so as to restrict the relevant parameters of the wastewater below ... is a highly efficient, low cost, low carbon emission footprint system for.

  8. The human cerebellum: a review of physiologic neuroanatomy.

    Science.gov (United States)

    Roostaei, Tina; Nazeri, Arash; Sahraian, Mohammad Ali; Minagar, Alireza

    2014-11-01

    The cerebellum resides in the posterior cranial fossa dorsal to the brainstem and has diverse connections to the cerebrum, brain stem, and spinal cord. It is anatomically and physiologically divided into distinct functional compartments and is composed of highly regular arrays of neuronal units, each sharing the same basic cerebellar microcircuitry. Its circuitry is critically involved in motor control and motor learning, and its role in nonmotor cognitive and affective functions is becoming increasingly recognized. This article describes the cerebellar gross and histologic neuroanatomy in relation to its function, and the relevance of cerebellar circuitry and firing patterns to motor learning. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. A Human Life-Stage Physiologically Based Pharmacokinetic and Pharmacodynamic Model for Chlorpyrifos: Development and Validation

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Jordan N.; Hinderliter, Paul M.; Timchalk, Charles; Bartels, M. J.; Poet, Torka S.

    2014-08-01

    Sensitivity to chemicals in animals and humans are known to vary with age. Age-related changes in sensitivity to chlorpyrifos have been reported in animal models. A life-stage physiologically based pharmacokinetic and pharmacodynamic (PBPK/PD) model was developed to computationally predict disposition of CPF and its metabolites, chlorpyrifos-oxon (the ultimate toxicant) and 3,5,6-trichloro-2-pyridinol (TCPy), as well as B-esterase inhibition by chlorpyrifos-oxon in humans. In this model, age-dependent body weight was calculated from a generalized Gompertz function, and compartments (liver, brain, fat, blood, diaphragm, rapid, and slow) were scaled based on body weight from polynomial functions on a fractional body weight basis. Blood flows among compartments were calculated as a constant flow per compartment volume. The life-stage PBPK/PD model was calibrated and tested against controlled adult human exposure studies. Model simulations suggest age-dependent pharmacokinetics and response may exist. At oral doses ≥ 0.55 mg/kg of chlorpyrifos (significantly higher than environmental exposure levels), 6 mo old children are predicted to have higher levels of chlorpyrifos-oxon in blood and higher levels of red blood cell cholinesterase inhibition compared to adults from equivalent oral doses of chlorpyrifos. At lower doses that are more relevant to environmental exposures, the model predicts that adults will have slightly higher levels of chlorpyrifos-oxon in blood and greater cholinesterase inhibition. This model provides a computational framework for age-comparative simulations that can be utilized to predict CPF disposition and biological response over various postnatal life-stages.

  10. Fluid flow and convective transport of solutes within the intervertebral disc.

    Science.gov (United States)

    Ferguson, Stephen J; Ito, Keita; Nolte, Lutz P

    2004-02-01

    Previous experimental and analytical studies of solute transport in the intervertebral disc have demonstrated that for small molecules diffusive transport alone fulfils the nutritional needs of disc cells. It has been often suggested that fluid flow into and within the disc may enhance the transport of larger molecules. The goal of the study was to predict the influence of load-induced interstitial fluid flow on mass transport in the intervertebral disc. An iterative procedure was used to predict the convective transport of physiologically relevant molecules within the disc. An axisymmetric, poroelastic finite-element structural model of the disc was developed. The diurnal loading was divided into discrete time steps. At each time step, the fluid flow within the disc due to compression or swelling was calculated. A sequentially coupled diffusion/convection model was then employed to calculate solute transport, with a constant concentration of solute being provided at the vascularised endplates and outer annulus. Loading was simulated for a complete diurnal cycle, and the relative convective and diffusive transport was compared for solutes with molecular weights ranging from 400 Da to 40 kDa. Consistent with previous studies, fluid flow did not enhance the transport of low-weight solutes. During swelling, interstitial fluid flow increased the unidirectional penetration of large solutes by approximately 100%. Due to the bi-directional temporal nature of disc loading, however, the net effect of convective transport over a full diurnal cycle was more limited (30% increase). Further study is required to determine the significance of large solutes and the timing of their delivery for disc physiology.

  11. 5α-reductases in human physiology: an unfolding story.

    Science.gov (United States)

    Traish, Abdulmaged M

    2012-01-01

    5α-reductases are a family of isozymes expressed in a wide host of tissues including the central nervous system (CNS) and play a pivotal role in male sexual differentiation, development and physiology. A comprehensive literature search from 1970 to 2011 was made through PubMed and the relevant information was summarized. 5α reductases convert testosterone, progesterone, deoxycorticosterone, aldosterone and corticosterone into their respective 5α-dihydro-derivatives, which serve as substrates for 3α-hydroxysteroid dehydrogenase enzymes. The latter transforms these 5α-reduced metabolites into a subclass of neuroactive steroid hormones with distinct physiological functions. The neuroactive steroid hormones modulate a multitude of functions in human physiology encompassing regulation of sexual differentiation, neuroprotection, memory enhancement, anxiety, sleep and stress, among others. In addition, 5α -reductase type 3 is also implicated in the N-glycosylation of proteins via formation of dolichol phosphate. The family of 5α-reductases was targeted for drug development to treat pathophysiological conditions, such as benign prostatic hyperplasia and androgenetic alopecia. While the clinical use of 5α-reductase inhibitors was well established, the scope and the magnitude of the adverse side effects of such drugs, especially on the CNS, is still unrecognized due to lack of knowledge of the various physiological functions of this family of enzymes, especially in the CNS. There is an urgent need to better understand the function of 5α-reductases and the role of neuroactive steroids in human physiology in order to minimize the potential adverse side effects of inhibitors targeting 5α-reductases to treat benign prostatic hyperplasia and androgenic alopecia.

  12. Oscillatory flow chemical reactors

    Directory of Open Access Journals (Sweden)

    Slavnić Danijela S.

    2014-01-01

    Full Text Available Global market competition, increase in energy and other production costs, demands for high quality products and reduction of waste are forcing pharmaceutical, fine chemicals and biochemical industries, to search for radical solutions. One of the most effective ways to improve the overall production (cost reduction and better control of reactions is a transition from batch to continuous processes. However, the reactions of interests for the mentioned industry sectors are often slow, thus continuous tubular reactors would be impractically long for flow regimes which provide sufficient heat and mass transfer and narrow residence time distribution. The oscillatory flow reactors (OFR are newer type of tube reactors which can offer solution by providing continuous operation with approximately plug flow pattern, low shear stress rates and enhanced mass and heat transfer. These benefits are the result of very good mixing in OFR achieved by vortex generation. OFR consists of cylindrical tube containing equally spaced orifice baffles. Fluid oscillations are superimposed on a net (laminar flow. Eddies are generated when oscillating fluid collides with baffles and passes through orifices. Generation and propagation of vortices create uniform mixing in each reactor cavity (between baffles, providing an overall flow pattern which is close to plug flow. Oscillations can be created by direct action of a piston or a diaphragm on fluid (or alternatively on baffles. This article provides an overview of oscillatory flow reactor technology, its operating principles and basic design and scale - up characteristics. Further, the article reviews the key research findings in heat and mass transfer, shear stress, residence time distribution in OFR, presenting their advantages over the conventional reactors. Finally, relevant process intensification examples from pharmaceutical, polymer and biofuels industries are presented.

  13. Does relevance matter in academic policy research?

    DEFF Research Database (Denmark)

    Dredge, Dianne

    2015-01-01

    A reflection on whether relevance matters in tourism policy research. A debate among tourism scholars.......A reflection on whether relevance matters in tourism policy research. A debate among tourism scholars....

  14. CH2 - Lighting and Physiology

    Directory of Open Access Journals (Sweden)

    Sergio Altomonte

    2012-11-01

    Full Text Available This paper explains the designed performances of the new CH2 building in Melbourne, Australia. CH2 is an environmentally significant project that involves biomimicry of natural systems to produce indoor conditions that are conducive to user comfort, health and productivity. This paper focuses on lighting and physiology and examines the solutions chosen for artificial and natural lighting and the likely effects these will have on building occupants. The purpose of the paper is to critically comment on the adopted strategy and, cognisance of contemporary thinking in lighting design, to judge the effectiveness of this aspect of the project with a view to later verification and post-occupancy review. The paper concludes that CH2 is an exemplar of lighting innovation that provides valuable lessons to designers of office buildings, particularly in the Melbourne CSD.

  15. Neuronal responses to physiological stress

    DEFF Research Database (Denmark)

    Kagias, Konstantinos; Nehammer, Camilla; Pocock, Roger David John

    2012-01-01

    damage during aging that results in decline and eventual death. Studies have shown that the nervous system plays a pivotal role in responding to stress. Neurons not only receive and process information from the environment but also actively respond to various stresses to promote survival. These responses......Physiological stress can be defined as any external or internal condition that challenges the homeostasis of a cell or an organism. It can be divided into three different aspects: environmental stress, intrinsic developmental stress, and aging. Throughout life all living organisms are challenged...... by changes in the environment. Fluctuations in oxygen levels, temperature, and redox state for example, trigger molecular events that enable an organism to adapt, survive, and reproduce. In addition to external stressors, organisms experience stress associated with morphogenesis and changes in inner...

  16. Physiologically based pharmacokinetics model for estimating urinary excretion of short half-life nuclides in nuclear medicine

    International Nuclear Information System (INIS)

    Akahane, K.; Kai, M.; Konishi, E.; Kusama, T.; Aoki, Y.

    1995-01-01

    The biokinetic model in ICRP 53 is used for calculating absorbed dose to each organ of a patient in nuclear medicine. The ICRP model is a simple compartment model based on human data; however, the model cannot produce the biokinetics of radiopharmaceuticals under various physiological conditions. On the other hand, a physiologically based pharmacokinetics model (PBPK model) can describe the flow of radiopharmaceuticals as a compartment model for any physiological conditions theoretically. The PBPK model was applied especially for the kidney-bladder dynamics, and similar results obtained compared with the ICRP model. This suggests the possibility of the PBPK model for predicting the biokinetics of radiopharmaceuticals under various physiological conditions. (Author)

  17. Pulse wave analysis in a 180-degree curved artery model: Implications under physiological and non-physiological inflows

    Science.gov (United States)

    Bulusu, Kartik V.; Plesniak, Michael W.

    2013-11-01

    Systolic and diastolic blood pressures, pulse pressures, and left ventricular hypertrophy contribute to cardiovascular risks. Increase of arterial stiffness due to aging and hypertension is an important factor in cardiovascular, chronic kidney and end-stage-renal-diseases. Pulse wave analysis (PWA) based on arterial pressure wave characteristics, is well established in clinical practice for evaluation of arterial distensibility and hypertension. The objective of our exploratory study in a rigid 180-degree curved artery model was to evaluate arterial pressure waveforms. Bend upstream conditions were measured using a two-component, two-dimensional, particle image velocimeter (2C-2D PIV). An ultrasonic transit-time flow meter and a catheter with a MEMS-based solid state pressure sensor, capable of measuring up to 20 harmonics of the observed pressure waveform, monitored flow conditions downstream of the bend. Our novel continuous wavelet transform algorithm (PIVlet 1.2), in addition to detecting coherent secondary flow structures is used to evaluate arterial pulse wave characteristics subjected to physiological and non-physiological inflows. Results of this study will elucidate the utility of wavelet transforms in arterial function evaluation and pulse wave speed. Supported by NSF Grant No. CBET- 0828903 and GW Center for Biomimetics and Bioinspired Engineering.

  18. Cesium-137: A physiological disruptor?

    International Nuclear Information System (INIS)

    Souidi, Maamar; Grison, Stephane; Dublineau, Isabelle; Aigueperse, Jocelyne; Lestaevel, Philippe

    2013-01-01

    Today, radiation protection is a major issue for the nuclear industry throughout the world, particularly in France. The 2011 disaster of Fukushima Dai-ichi has brought back to public attention questions about the risks associated with nuclear power for civilian purposes. The risk of accidental release of radioactive molecules, including cesium-137 ( 137 Cs), from these facilities cannot be completely eliminated. The non-cancer-related health consequences of chronic exposure to this radionuclide remain poorly understood. After absorption, cesium is distributed throughout the body. The toxicity of 137 Cs is due mainly to its radiological properties. Studies in humans report that 137 Cs impairs the immune system and induces neurological disorders. Children appear more susceptible than adults to its toxic effects. In animals, and most particularly in rodents, low-dose internal contamination disrupts the sleep-wake cycle, but without behavioural disorders. Impairment of the cardiovascular system has also been observed. Physiologic systems such as the metabolism of vitamin D, cholesterol and steroid hormones are altered, although without leading to the emergence of diseases with clinical symptoms. Recently, a metabolomics study based on contamination levels comparable to those around Chernobyl after the accident showed that it is possible to identify individual rats chronically exposed to low doses of 137 Cs, even though the exposure was too low to affect the standard clinical markers. In conclusion, the scientific evidence currently available, particularly that from experimental animal models exposed to chronic contamination, suggests that 137 Cs is likely to affect many physiologic and metabolic functions. Thus, it could contribute, with other artificial substances in the environment, to increasing the risk of developing non-cancer diseases in some regions. (authors)

  19. The physiology of mountain biking.

    Science.gov (United States)

    Impellizzeri, Franco M; Marcora, Samuele M

    2007-01-01

    Mountain biking is a popular outdoor recreational activity and an Olympic sport. Cross-country circuit races have a winning time of approximately equal 120 minutes and are performed at an average heart rate close to 90% of the maximum, corresponding to 84% of maximum oxygen uptake (VO2max). More than 80% of race time is spent above the lactate threshold. This very high exercise intensity is related to the fast starting phase of the race; the several climbs, forcing off-road cyclists to expend most of their effort going against gravity; greater rolling resistance; and the isometric contractions of arm and leg muscles necessary for bike handling and stabilisation. Because of the high power output (up to 500W) required during steep climbing and at the start of the race, anaerobic energy metabolism is also likely to be a factor of off-road cycling and deserves further investigation. Mountain bikers' physiological characteristics indicate that aerobic power (VO2max >70 mL/kg/min) and the ability to sustain high work rates for prolonged periods of time are prerequisites for competing at a high level in off-road cycling events. The anthropometric characteristics of mountain bikers are similar to climbers and all-terrain road cyclists. Various parameters of aerobic fitness are correlated to cross-country performance, suggesting that these tests are valid for the physiological assessment of competitive mountain bikers, especially when normalised to body mass. Factors other than aerobic power and capacity might influence off-road cycling performance and require further investigation. These include off-road cycling economy, anaerobic power and capacity, technical ability and pre-exercise nutritional strategies.

  20. Science and the struggle for relevance

    NARCIS (Netherlands)

    Hessels, L.K.|info:eu-repo/dai/nl/304832863

    2010-01-01

    This thesis deals with struggles for relevance of university researchers, their efforts to make their work correspond with ruling standards of relevance and to influence these standards. Its general research question is: How to understand changes in the struggle for relevance of Dutch academic

  1. The Personal Relevance of the Social Studies.

    Science.gov (United States)

    VanSickle, Ronald L.

    1990-01-01

    Conceptualizes a personal-relevance framework derived from Ronald L. VanSickle's five areas of life integrated with four general motivating goals from Abraham Maslow's hierarchy of needs and Richard and Patricia Schmuck's social motivation theory. Illustrates ways to apply the personal relevance framework to make social studies more relevant to…

  2. The Development of Relevance in Information Retrieval

    Directory of Open Access Journals (Sweden)

    Mu-hsuan Huang

    1997-12-01

    Full Text Available This article attempts to investigate the notion of relevance in information retrieval. It discusses various definitions for relevance from historical viewpoints and the characteristics of relevance judgments. Also, it introduces empirical results of important related researches.[Article content in Chinese

  3. Pathways of the Maillard reaction under physiological conditions.

    Science.gov (United States)

    Henning, Christian; Glomb, Marcus A

    2016-08-01

    Initially investigated as a color formation process in thermally treated foods, nowadays, the relevance of the Maillard reaction in vivo is generally accepted. Many chronic and age-related diseases such as diabetes, uremia, atherosclerosis, cataractogenesis and Alzheimer's disease are associated with Maillard derived advanced glycation endproducts (AGEs) and α-dicarbonyl compounds as their most important precursors in terms of reactivity and abundance. However, the situation in vivo is very challenging, because Maillard chemistry is paralleled by enzymatic reactions which can lead to both, increases and decreases in certain AGEs. In addition, mechanistic findings established under the harsh conditions of food processing might not be valid under physiological conditions. The present review critically discusses the relevant α-dicarbonyl compounds as central intermediates of AGE formation in vivo with a special focus on fragmentation pathways leading to formation of amide-AGEs.

  4. Translational physiology: from molecules to public health.

    Science.gov (United States)

    Seals, Douglas R

    2013-07-15

    The term 'translational research' was coined 20 years ago and has become a guiding influence in biomedical research. It refers to a process by which the findings of basic research are extended to the clinical research setting (bench to bedside) and then to clinical practice and eventually health policy (bedside to community). It is a dynamic, multidisciplinary research approach. The concept of translational physiology applies the translational research model to the physiological sciences. It differs from the traditional areas of integrative and clinical physiology by its broad investigative scope of basic research to community health. Translational physiology offers exciting opportunities, but presently is under-developed and -utilized. A key challenge will be to expand physiological research by extending investigations to communities of patients and healthy (or at risk) individuals. This will allow bidirectional physiological investigation throughout the translational continuum: basic research observations can be studied up to the population level, and mechanisms can be assessed by 'reverse translation' in clinical research settings and preclinical models based on initial observations made in populations. Examples of translational physiology questions, experimental approaches, roadblocks and strategies for promotion are discussed. Translational physiology provides a novel framework for physiology programs and an investigational platform for physiologists to study function from molecular events to public health. It holds promise for enhancing the completeness and societal impact of our work, while further solidifying the critical role of physiology in the biomedical research enterprise.

  5. Visual presentation of a medical physiology seminar modifies dental students' perception of its clinical significance.

    Science.gov (United States)

    Vuletic, L; Spalj, S; Peros, K

    2016-02-01

    The primary objective of this study was to assess whether exposing dental students to visual stimuli related to dental profession during the medical physiology seminar could affect their perception of the clinical relevance of the topic. A self-administered questionnaire on attitudes towards medical physiology was conducted amongst 105 students of the School of Dental Medicine in Zagreb, Croatia, aged 19-24 years (80% females) following a seminar on respiratory system physiology. Power-point presentation accompanying the seminar for a total of 52 students (study group) was enriched with pictures related to dental practice in order to assess whether these pictures could make the topic appear more clinically relevant for a future dentist. The results of the survey indicated that dental students in the study group perceived the topic of the seminar as more important for them as future dentists when compared to the perception of the control group (P = 0.025). The results of this survey encourage physiology lecturers to present medical physiology as clinically relevant for dental students whenever possible as this could increase students' interest in the subject and their motivation for learning. Such an approach could be particularly beneficial if there is a significant time gap between basic courses and involvement of students into clinical training for it could promote meaningful learning. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. Intracranial Aneurysms of Neuro-Ophthalmologic Relevance.

    Science.gov (United States)

    Micieli, Jonathan A; Newman, Nancy J; Barrow, Daniel L; Biousse, Valérie

    2017-12-01

    Intracranial saccular aneurysms are acquired lesions that often present with neuro-ophthalmologic symptoms and signs. Recent advances in neurosurgical techniques, endovascular treatments, and neurocritical care have improved the optimal management of symptomatic unruptured aneurysms, but whether the chosen treatment has an impact on neuro-ophthalmologic outcomes remains debated. A review of the literature focused on neuro-ophthalmic manifestations and treatment of intracranial aneurysms with specific relevance to neuro-ophthalmologic outcomes was conducted using Ovid MEDLINE and EMBASE databases. Cavernous sinus aneurysms were not included in this review. Surgical clipping vs endovascular coiling for aneurysms causing third nerve palsies was compared in 13 retrospective studies representing 447 patients. Complete recovery was achieved in 78% of surgical patients compared with 44% of patients treated with endovascular coiling. However, the complication rate, hospital costs, and days spent in intensive care were reported as higher in surgically treated patients. Retrospective reviews of surgical clipping and endovascular coiling for all ocular motor nerve palsies (third, fourth, or sixth cranial nerves) revealed similar results of complete resolution in 76% and 49%, respectively. Improvement in visual deficits related to aneurysmal compression of the anterior visual pathways was also better among patients treated with clipping than with coiling. The time to treatment from onset of visual symptoms was a predictive factor of visual recovery in several studies. Few reports have specifically assessed the improvement of visual deficits after treatment with flow diverters. Decisions regarding the choice of therapy for intracranial aneurysms causing neuro-ophthalmologic signs ideally should be made at high-volume centers with access to both surgical and endovascular treatments. The status of the patient, location of the aneurysm, and experience of the treating physicians

  7. Nostalgia's place among self-relevant emotions.

    Science.gov (United States)

    van Tilburg, Wijnand A P; Wildschut, Tim; Sedikides, Constantine

    2017-07-24

    How is nostalgia positioned among self-relevant emotions? We tested, in six studies, which self-relevant emotions are perceived as most similar versus least similar to nostalgia, and what underlies these similarities/differences. We used multidimensional scaling to chart the perceived similarities/differences among self-relevant emotions, resulting in two-dimensional models. The results were revealing. Nostalgia is positioned among self-relevant emotions characterised by positive valence, an approach orientation, and low arousal. Nostalgia most resembles pride and self-compassion, and least resembles embarrassment and shame. Our research pioneered the integration of nostalgia among self-relevant emotions.

  8. From Claude Bernard to the Batcave and Beyond: Using Batman as a Hook for Physiology Education

    Science.gov (United States)

    Zehr, E. Paul

    2011-01-01

    Communicating physiology to the general public and popularizing science can be tremendously rewarding activities. Providing relevant and compelling points of linkage, however, between the scientific experiences and the interests of the general public can be challenging. One avenue for popularizing science is to link scientific concepts to images,…

  9. Intragroup emotions: physiological linkage and social presence

    Directory of Open Access Journals (Sweden)

    Simo eJärvelä

    2016-02-01

    Full Text Available We investigated how technologically mediating two different components of emotion – communicative expression and physiological state – to group members affects physiological linkage and self-reported feelings in a small group during video viewing. In different conditions the availability of second screen text chat (communicative expression and visualization of group level physiological heart rates and their dyadic linkage (physiology was varied. Within this four person group two participants formed a physically co-located dyad and the other two were individually situated in two separate rooms. We found that text chat always increased heart rate synchrony but HR visualization only with non-co-located dyads. We also found that physiological linkage was strongly connected to self-reported social presence. The results encourage further exploration of the possibilities of sharing group member’s physiological components of emotion by technological means to enhance mediated communication and strengthen social presence.

  10. Intragroup Emotions: Physiological Linkage and Social Presence.

    Science.gov (United States)

    Järvelä, Simo; Kätsyri, Jari; Ravaja, Niklas; Chanel, Guillaume; Henttonen, Pentti

    2016-01-01

    We investigated how technologically mediating two different components of emotion-communicative expression and physiological state-to group members affects physiological linkage and self-reported feelings in a small group during video viewing. In different conditions the availability of second screen text chat (communicative expression) and visualization of group level physiological heart rates and their dyadic linkage (physiology) was varied. Within this four person group two participants formed a physically co-located dyad and the other two were individually situated in two separate rooms. We found that text chat always increased heart rate synchrony but HR visualization only with non-co-located dyads. We also found that physiological linkage was strongly connected to self-reported social presence. The results encourage further exploration of the possibilities of sharing group member's physiological components of emotion by technological means to enhance mediated communication and strengthen social presence.

  11. Intragroup Emotions: Physiological Linkage and Social Presence

    Science.gov (United States)

    Järvelä, Simo; Kätsyri, Jari; Ravaja, Niklas; Chanel, Guillaume; Henttonen, Pentti

    2016-01-01

    We investigated how technologically mediating two different components of emotion—communicative expression and physiological state—to group members affects physiological linkage and self-reported feelings in a small group during video viewing. In different conditions the availability of second screen text chat (communicative expression) and visualization of group level physiological heart rates and their dyadic linkage (physiology) was varied. Within this four person group two participants formed a physically co-located dyad and the other two were individually situated in two separate rooms. We found that text chat always increased heart rate synchrony but HR visualization only with non-co-located dyads. We also found that physiological linkage was strongly connected to self-reported social presence. The results encourage further exploration of the possibilities of sharing group member's physiological components of emotion by technological means to enhance mediated communication and strengthen social presence. PMID:26903913

  12. Continuous positive airway pressure: Physiology and comparison of devices.

    Science.gov (United States)

    Gupta, Samir; Donn, Steven M

    2016-06-01

    Nasal continuous positive airway pressure (CPAP) is increasingly used for respiratory support in preterm babies at birth and after extubation from mechanical ventilation. Various CPAP devices are available for use that can be broadly grouped into continuous flow and variable flow. There are potential physiologic differences between these CPAP systems and the choice of a CPAP device is too often guided by individual expertise and experience rather than by evidence. When interpreting the evidence clinicians should take into account the pressure generation sources, nasal interface, and the factors affecting the delivery of pressure, such as mouth position and respiratory drive. With increasing use of these devices, better monitoring techniques are required to assess the efficacy and early recognition of babies who are failing and in need of escalated support. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Bacterial multidrug efflux pumps: mechanisms, physiology and pharmacological exploitations.

    Science.gov (United States)

    Sun, Jingjing; Deng, Ziqing; Yan, Aixin

    2014-10-17

    Multidrug resistance (MDR) refers to the capability of bacterial pathogens to withstand lethal doses of structurally diverse drugs which are capable of eradicating non-resistant strains. MDR has been identified as a major threat to the public health of human being by the World Health Organization (WHO). Among the four general mechanisms that cause antibiotic resistance including target alteration, drug inactivation, decreased permeability and increased efflux, drug extrusion by the multidrug efflux pumps serves as an important mechanism of MDR. Efflux pumps not only can expel a broad range of antibiotics owing to their poly-substrate specificity, but also drive the acquisition of additional resistance mechanisms by lowering intracellular antibiotic concentration and promoting mutation accumulation. Over-expression of multidrug efflux pumps have been increasingly found to be associated with clinically relevant drug resistance. On the other hand, accumulating evidence has suggested that efflux pumps also have physiological functions in bacteria and their expression is subject tight regulation in response to various of environmental and physiological signals. A comprehensive understanding of the mechanisms of drug extrusion, and regulation and physiological functions of efflux pumps is essential for the development of anti-resistance interventions. In this review, we summarize the development of these research areas in the recent decades and present the pharmacological exploitation of efflux pump inhibitors as a promising anti-drug resistance intervention. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  14. Physiological performance and thermal tolerance of major Red Sea macrophytes

    KAUST Repository

    Weinzierl, Michael S.

    2017-12-01

    As anthropogenically-forced ocean temperatures continue to rise, the physiological response of marine macrophytes becomes exceedingly relevant. The Red Sea is a semi-isolated sea- the warmest in the world (SST up to 34°C) - already exhibiting signs of rapid warming rates exceeding those of other tropical oceans. This will have profound effects on the physiology of marine organisms, specifically marine macrophytes, which have direct influence on the dynamic carbonate system of the Red Sea. The aim of this paper is to define the physiological capability and thermal optima and limits of six ecologically important Red Sea macrophytes- ranging from seagrasses to calcifying and non-calcifying algae- and to describe the effects of increasing thermal stress on the performance and limits of each macrophyte in terms of activation energy. Of the species considered, Halophila stipulacae, Halimeda optunia, Halimeda monile and Padina pavonica thrive in thermal extremes and may be more successful in future Red Sea warming scenarios. Specifically, Halimeda opuntia increased productivity and calcification rates up to 38°C, making it the most thermally resilient macrophyte. Halophila stipulacae is the most productive seagrass, and hence has the greatest positive effect on Omega saturation state and offers chemical buffer capacity to future ocean acidification.

  15. Physiological and Environmental Sensor Skin Stamp

    Data.gov (United States)

    National Aeronautics and Space Administration — Future exploration missions will require astronauts to autonomously monitor physiological and atmospheric conditions. Recent technological advances in the developing...

  16. AN OVERVIEW ON PULSATILE FLOW DYNAMICS

    OpenAIRE

    Çarpinlioğlu, Melda Özdinç

    2015-01-01

    Pulsatile flow dynamics in reference to the relevant experimental research on the manner between the time periods of 1997- 2015 is presented in this paper. The flow field under discussion is generated through a rigid circular cross-sectional pipe as an axial slightly- compressible and sinusoidal one in a controlled range of the oscillation parameters. Laminar and turbulent flow regimes are considered with a particular emphasis devoted to the transitional characteristics of laminar pulsatile f...

  17. Clinical physiology of bed rest

    Science.gov (United States)

    Greenleaf, John E.

    1993-01-01

    Maintenance of optimal health in humans requires the proper balance between exercise, rest, and sleep as well as time in the upright position. About one-third of a lifetime is spent sleeping; and it is no coincidence that sleeping is performed in the horizontal position, the position in which gravitational influence on the body is minimal. Although enforced bed rest is necessary for the treatment of some ailments, in some cases it has probably been used unwisely. In addition to the lower hydrostatic pressure with the normally dependent regions of the cardiovascular system, body fuid compartments during bed rest in the horizontal body position, and virtual elimination of compression on the long bones of the skeletal system during bed rest (hypogravia), there is often reduction in energy metabolism due to the relative confinement (hypodynamia) and alteration of ambulatory circadian variations in metabolism, body temperature, and many hormonal systems. If patients are also moved to unfamiliar surroundings, they probably experience some feelings of anxiety and some sociopsychological problems. Adaptive physiological responses during bed rest are normal for that environment. They are attempts by the body to reduce unnecessary energy expenditure, to optimize its function, and to enhance its survival potential. Many of the deconditioning responses begin within the first day or two of bed rest; these early responses have prompted physicians to insist upon early resumption of the upright posture and ambulation of bedridden patients.

  18. Computational Modeling of Space Physiology

    Science.gov (United States)

    Lewandowski, Beth E.; Griffin, Devon W.

    2016-01-01

    The Digital Astronaut Project (DAP), within NASAs Human Research Program, develops and implements computational modeling for use in the mitigation of human health and performance risks associated with long duration spaceflight. Over the past decade, DAP developed models to provide insights into space flight related changes to the central nervous system, cardiovascular system and the musculoskeletal system. Examples of the models and their applications include biomechanical models applied to advanced exercise device development, bone fracture risk quantification for mission planning, accident investigation, bone health standards development, and occupant protection. The International Space Station (ISS), in its role as a testing ground for long duration spaceflight, has been an important platform for obtaining human spaceflight data. DAP has used preflight, in-flight and post-flight data from short and long duration astronauts for computational model development and validation. Examples include preflight and post-flight bone mineral density data, muscle cross-sectional area, and muscle strength measurements. Results from computational modeling supplement space physiology research by informing experimental design. Using these computational models, DAP personnel can easily identify both important factors associated with a phenomenon and areas where data are lacking. This presentation will provide examples of DAP computational models, the data used in model development and validation, and applications of the model.

  19. Food, physiology and drug delivery.

    Science.gov (United States)

    Varum, F J O; Hatton, G B; Basit, A W

    2013-12-05

    Gastrointestinal physiology is dynamic and complex at the best of times, and a multitude of known variables can affect the overall bioavailability of drugs delivered via the oral route. Yet while the influences of food and beverage intake as just two of these variables on oral drug delivery have been extensively documented in the wider literature, specific information on their effects remains sporadic, and is not so much contextually reviewed. Food co-ingestion with oral dosage forms can mediate several changes to drug bioavailability, yet the precise mechanisms underlying this have yet to be fully elucidated. Likewise, the often detrimental effects of alcohol (ethanol) on dosage form performance have been widely observed experimentally, but knowledge of which has only moderately impacted on clinical practice. Here, we attempt to piece together the available subject matter relating to the influences of both solid and liquid foodstuffs on the gastrointestinal milieu and the implications for oral drug delivery, with particular emphasis on the behaviour of modified-release dosage forms, formulation robustness and drug absorption. Providing better insight into these influences, and exemplifying cases where formulations have been developed or modified to circumvent their associated problems, can help to appropriately direct the design of future in vitro digestive modelling systems as well as oral dosage forms resilient to these effects. Moreover, this will help to better our understanding of the impact of food and alcohol intake on normal gut behaviour and function. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Virtual physiological human: training challenges.

    Science.gov (United States)

    Lawford, Patricia V; Narracott, Andrew V; McCormack, Keith; Bisbal, Jesus; Martin, Carlos; Bijnens, Bart; Brook, Bindi; Zachariou, Margarita; Freixa, Jordi Villà I; Kohl, Peter; Fletcher, Katherine; Diaz-Zuccarini, Vanessa

    2010-06-28

    The virtual physiological human (VPH) initiative encompasses a wide range of activities, including structural and functional imaging, data mining, knowledge discovery tool and database development, biomedical modelling, simulation and visualization. The VPH community is developing from a multitude of relatively focused, but disparate, research endeavours into an integrated effort to bring together, develop and translate emerging technologies for application, from academia to industry and medicine. This process initially builds on the evolution of multi-disciplinary interactions and abilities, but addressing the challenges associated with the implementation of the VPH will require, in the very near future, a translation of quantitative changes into a new quality of highly trained multi-disciplinary personnel. Current strategies for undergraduate and on-the-job training may soon prove insufficient for this. The European Commission seventh framework VPH network of excellence is exploring this emerging need, and is developing a framework of novel training initiatives to address the predicted shortfall in suitably skilled VPH-aware professionals. This paper reports first steps in the implementation of a coherent VPH training portfolio.

  1. Anatomical physiology of spatial extinction.

    Science.gov (United States)

    Ciçek, Metehan; Gitelman, Darren; Hurley, Robert S E; Nobre, Anna; Mesulam, Marsel

    2007-12-01

    Neurologically intact volunteers participated in a functional magnetic resonance imaging experiment that simulated the unilateral (focal) and bilateral (global) stimulations used to elicit extinction in patients with hemispatial neglect. In peristriate areas, attentional modulations were selectively sensitive to contralaterally directed attention. A higher level of mapping was observed in the intraparietal sulcus (IPS), inferior parietal lobule (IPL), and inferior frontal gyrus (IFG). In these areas, there was no distinction between contralateral and ipsilateral focal attention, and the need to distribute attention globally led to greater activity than either focal condition. These physiological characteristics were symmetrically distributed in the IPS and IFG, suggesting that the effects of unilateral lesions in these 2 areas can be compensated by the contralateral hemisphere. In the IPL, the greater activation by the bilateral attentional mode was seen only in the right hemisphere. Its contralateral counterpart displayed equivalent activations when attention was distributed to the right, to the left, or bilaterally. Within the context of this experiment, the IPL of the right hemisphere emerged as the one area where unilateral lesions can cause the most uncompensated and selective impairment of global attention (without interfering with unilateral attention to either side), giving rise to the phenomenon of extinction.

  2. A comprehensive physiologically based pharmacokinetic ...

    Science.gov (United States)

    Published physiologically based pharmacokinetic (PBPK) models from peer-reviewed articles are often well-parameterized, thoroughly-vetted, and can be utilized as excellent resources for the construction of models pertaining to related chemicals. Specifically, chemical-specific parameters and in vivo pharmacokinetic data used to calibrate these published models can act as valuable starting points for model development of new chemicals with similar molecular structures. A knowledgebase for published PBPK-related articles was compiled to support PBPK model construction for new chemicals based on their close analogues within the knowledgebase, and a web-based interface was developed to allow users to query those close analogues. A list of 689 unique chemicals and their corresponding 1751 articles was created after analysis of 2,245 PBPK-related articles. For each model, the PMID, chemical name, major metabolites, species, gender, life stages and tissue compartments were extracted from the published articles. PaDEL-Descriptor, a Chemistry Development Kit based software, was used to calculate molecular fingerprints. Tanimoto index was implemented in the user interface as measurement of structural similarity. The utility of the PBPK knowledgebase and web-based user interface was demonstrated using two case studies with ethylbenzene and gefitinib. Our PBPK knowledgebase is a novel tool for ranking chemicals based on similarities to other chemicals associated with existi

  3. Monitoring the Erosion of Hydrolytically-Degradable Nanogels via Multiangle Light Scattering Coupled to Asymmetrical Flow Field-Flow Fractionation

    Science.gov (United States)

    Smith, Michael H.; South, Antoinette B.; Gaulding, Jeffrey C.; Lyon, L. Andrew

    2009-01-01

    We describe the synthesis and characterization of degradable nanogels that display bulk erosion under physiologic conditions (pH = 7.4, 37 °C). Erodible poly(N-isopropylmethacrylamide) nanogels were synthesized by copolymerization with N,O-(dimethacryloyl)hydroxylamine, a cross-linker previously used in the preparation of non-toxic and biodegradable bulk hydrogels. To monitor particle degradation, we employed multiangle light scattering and differential refractometry detection following asymmetrical flow field-flow fractionation. This approach allowed the detection of changes in nanogel molar mass and topology as a function of both temperature and pH. Particle erosion was evident from both an increase in nanogel swelling and a decrease in scattering intensity as a function of time. Following these analyses, the samples were recovered for subsequent characterization by direct particle tracking, which yields hydrodynamic size measurements and enables number density determination. Additionally, we confirmed the conservation of nanogel stimuli-responsivity through turbidity measurements. Thus, we have demonstrated the synthesis of degradable nanogels that erode under conditions and on timescales that are relevant for many drug delivery applications. The combined separation and light scattering detection method is demonstrated to be a versatile means to monitor erosion and should also find applicability in the characterization of other degradable particle constructs. PMID:20000662

  4. Spatiotemporal evolution of cavitation dynamics exhibited by flowing microbubbles during ultrasound exposure.

    Science.gov (United States)

    Choi, James J; Coussios, Constantin-C

    2012-11-01

    Ultrasound and microbubble-based therapies utilize cavitation to generate bioeffects, yet cavitation dynamics during individual pulses and across consecutive pulses remain poorly understood under physiologically relevant flow conditions. SonoVue(®) microbubbles were made to flow (fluid velocity: 10-40 mm/s) through a vessel in a tissue-mimicking material and were exposed to ultrasound [frequency: 0.5 MHz, peak-rarefactional pressure (PRP): 150-1200 kPa, pulse length: 1-100,000 cycles, pulse repetition frequency (PRF): 1-50 Hz, number of pulses: 10-250]. Radiated emissions were captured on a linear array, and passive acoustic mapping was used to spatiotemporally resolve cavitation events. At low PRPs, stable cavitation was maintained throughout several pulses, thus generating a steady rise in energy with low upstream spatial bias within the focal volume. At high PRPs, inertial cavitation was concentrated in the first 6.3 ± 1.3 ms of a pulse, followed by an energy reduction and high upstream bias. Multiple pulses at PRFs below a flow-dependent critical rate (PRF(crit)) produced predictable and consistent cavitation dynamics. Above the PRF(crit), energy generated was unpredictable and spatially biased. In conclusion, key parameters in microbubble-seeded flow conditions were matched with specific types, magnitudes, distributions, and durations of cavitation; this may help in understanding empirically observed in vivo phenomena and guide future pulse sequence designs.

  5. The functional relevance of polyploidization in the skin.

    Science.gov (United States)

    Trakala, Marianna; Malumbres, Marcos

    2014-02-01

    Cell proliferation and differentiation are tightly coupled through the regulation of the cell division cycle. To preserve specific functional properties in differentiated cells, distinct variants of the basic mitotic cell cycle are used in various mammalian tissues, leading to the formation of polyploid cells. In this issue of Experimental Dermatology, Gandarillas and Freije discuss the evidences for polyploidization in keratinocytes, a process whose physiological relevance is now becoming evident. A better evaluation of these unconventional cell cycles is required not only to improve our understanding of the development and structure of the epidermis but also for future therapies against skin diseases. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. Flow chemistry vs. flow analysis.

    Science.gov (United States)

    Trojanowicz, Marek

    2016-01-01

    The flow mode of conducting chemical syntheses facilitates chemical processes through the use of on-line analytical monitoring of occurring reactions, the application of solid-supported reagents to minimize downstream processing and computerized control systems to perform multi-step sequences. They are exactly the same attributes as those of flow analysis, which has solid place in modern analytical chemistry in several last decades. The following review paper, based on 131 references to original papers as well as pre-selected reviews, presents basic aspects, selected instrumental achievements and developmental directions of a rapidly growing field of continuous flow chemical synthesis. Interestingly, many of them might be potentially employed in the development of new methods in flow analysis too. In this paper, examples of application of flow analytical measurements for on-line monitoring of flow syntheses have been indicated and perspectives for a wider application of real-time analytical measurements have been discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Positive expiratory pressure - Common clinical applications and physiological effects.

    Science.gov (United States)

    Fagevik Olsén, Monika; Lannefors, Louise; Westerdahl, Elisabeth

    2015-03-01

    Breathing out against resistance, in order to achieve positive expiratory pressure (PEP), is applied by many patient groups. Pursed lips breathing and a variety of devices can be used to create the resistance giving the increased expiratory pressure. Effects on pulmonary outcomes have been discussed in several publications, but the expected underlying physiology of the effect is seldom discussed. The aim of this article is to describe the purpose, performance, clinical application and underlying physiology of PEP when it is used to increase lung volumes, decrease hyperinflation or improve airway clearance. In clinical practice, the instruction how to use an expiratory resistance is of major importance since it varies. Different breathing patterns during PEP increase or reduce expiratory flow, result in movement of EPP centrally or peripherally and can increase or decrease lung volume. It is therefore necessary to give the right instructions to obtain the desired effects. As the different PEP techniques are being used by diverse patient groups it is not possible to give standard instructions. Based on the information given in this article the instructions have to be adjusted to give the optimal effect. There is no consensus regarding optimal treatment frequency and number of cycles included in each treatment session and must also be individualized. In future research, more precise descriptions are needed about physiological aims and specific instructions of how the treatments have been performed to assure as good treatment quality as possible and to be able to evaluate and compare treatment effects. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Application of magnetic resonance techniques for imaging tumour physiology

    International Nuclear Information System (INIS)

    Stubbs, M.

    1999-01-01

    Magnetic resonance (MR) techniques have the unique ability to measure in vivo the biochemical content of living tissue in the body in a dynamic, non-invasive and non-destructive manner. MR also permits serial investigations of steady-state tumour physiology and biochemistry, as well as the response of a tumour to treatment. Magnetic resonance imaging (MRI), Magnetic resonance spectroscopy (MRS) and a mixture of the two techniques (spectroscopic imaging) allow some physiological parameters, for example pH, to be 'imaged'. Using these methods, information on tissue bioenergetics and phospolipid membrane turnover, pH, hypoxia, oxygenation, and various aspects of vascularity including blood flow, angiogenesis, permeability and vascular volume can be obtained. In addition, MRS methods can be used for monitoring anticancer drugs (e.g. 5FU, ifosfamide) and their metabolites at their sites of action. The role of these state-of-the-art MR methods in imaging tumour physiology and their potential role in the clinic are discussed. (orig.)

  9. Vortical flows

    International Nuclear Information System (INIS)

    Wu, Jie-Zhi; Ma, Hui-Yang; Zhou, Ming-De

    2015-01-01

    This book is a comprehensive and intensive book for graduate students in fluid dynamics as well as scientists, engineers and applied mathematicians. Offering a systematic introduction to the physical theory of vortical flows at graduate level, it considers the theory of vortical flows as a branch of fluid dynamics focusing on shearing process in fluid motion, measured by vorticity. It studies vortical flows according to their natural evolution stages,from being generated to dissipated. As preparation, the first three chapters of the book provide background knowledge for entering vortical flows. The rest of the book deals with vortices and vortical flows, following their natural evolution stages. Of various vortices the primary form is layer-like vortices or shear layers, and secondary but stronger form is axial vortices mainly formed by the rolling up of shear layers. Problems are given at the end of each chapter and Appendix, some for helping understanding the basic theories, and some involving specific applications; but the emphasis of both is always on physical thinking.

  10. Vortical flows

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jie-Zhi [Peking Univ., Beijing (China). College of Engineering; Ma, Hui-Yang [Univ. of Chinese Academy of Sciences, Beijing (China). Dept. of Physics; Zhou, Ming-De [Arizona Univ., Tucson, AZ (United States). Dept. of Aerospace and Mechanical Engineering

    2015-11-01

    This book is a comprehensive and intensive book for graduate students in fluid dynamics as well as scientists, engineers and applied mathematicians. Offering a systematic introduction to the physical theory of vortical flows at graduate level, it considers the theory of vortical flows as a branch of fluid dynamics focusing on shearing process in fluid motion, measured by vorticity. It studies vortical flows according to their natural evolution stages,from being generated to dissipated. As preparation, the first three chapters of the book provide background knowledge for entering vortical flows. The rest of the book deals with vortices and vortical flows, following their natural evolution stages. Of various vortices the primary form is layer-like vortices or shear layers, and secondary but stronger form is axial vortices mainly formed by the rolling up of shear layers. Problems are given at the end of each chapter and Appendix, some for helping understanding the basic theories, and some involving specific applications; but the emphasis of both is always on physical thinking.

  11. Observing and understanding arterial and venous circulation differences in a physiology laboratory activity.

    Science.gov (United States)

    Altermann, Caroline; Gonçalves, Rithiele; Lara, Marcus Vinícius S; Neves, Ben-Hur S; Mello-Carpes, Pâmela B

    2015-12-01

    The purpose of the present article is to describe three simple practical experiments that aim to observe and discuss the anatomic and physiological functions and differences between arteries and veins as well as the alterations observed in skin blood flow in different situations. For this activity, students were divided in small groups. In each group, a volunteer is recruited for each experiment. The experiments only require a sphygmomanometer, rubber bands, and a clock and allow students to develop a hypothesis to explain the different responses to the interruption of arterial and venous blood flow. At the end, students prepare a short report, and the results are discussed. This activity allows students to perceive the presence of physiology in their daily lives and helps them to understand the concepts related to the cardiovascular system and hemodynamics. Copyright © 2015 The American Physiological Society.

  12. Physiological adaptation of endothelial function to pregnancy: systematic review and meta-analysis

    NARCIS (Netherlands)

    Balen, V.A.L. van; Gansewinkel, T.A.G. van; Haas, S.; Kuijk, S.M.J. van; Drongelen, J. van; Ghossein-Doha, C.; Spaanderman, M.E.A.

    2017-01-01

    OBJECTIVES: To establish reference values for flow-mediated dilatation (FMD) and brachial artery diameter (BAD) in pregnancy and to provide insight into the physiological and pathological course of endothelial adaptation throughout human singleton pregnancy. METHODS: A meta-analysis was performed

  13. Coronary Physiology During Exercise and Vasodilation in the Healthy Heart and in Severe Aortic Stenosis

    NARCIS (Netherlands)

    Lumley, Matthew; Williams, Rupert; Asrress, Kaleab N.; Arri, Satpal; Briceno, Natalia; Ellis, Howard; Rajani, Ronak; Siebes, Maria; Piek, Jan J.; Clapp, Brian; Redwood, Simon R.; Marber, Michael S.; Chambers, John B.; Perera, Divaka

    2016-01-01

    Severe aortic stenosis (AS) can manifest as exertional angina even in the presence of unobstructed coronary arteries. The authors describe coronary physiological changes during exercise and hyperemia in the healthy heart and in patients with severe AS. Simultaneous intracoronary pressure and flow

  14. Enhancing team-sport athlete performance: is altitude training relevant?

    Science.gov (United States)

    Billaut, François; Gore, Christopher J; Aughey, Robert J

    2012-09-01

    Field-based team sport matches are composed of short, high-intensity efforts, interspersed with intervals of rest or submaximal exercise, repeated over a period of 60-120 minutes. Matches may also be played at moderate altitude where the lower oxygen partial pressure exerts a detrimental effect on performance. To enhance run-based performance, team-sport athletes use varied training strategies focusing on different aspects of team-sport physiology, including aerobic, sprint, repeated-sprint and resistance training. Interestingly, 'altitude' training (i.e. living and/or training in O(2)-reduced environments) has only been empirically employed by athletes and coaches to improve the basic characteristics of speed and endurance necessary to excel in team sports. Hypoxia, as an additional stimulus to training, is typically used by endurance athletes to enhance performance at sea level and to prepare for competition at altitude. Several approaches have evolved in the last few decades, which are known to enhance aerobic power and, thus, endurance performance. Altitude training can also promote an increased anaerobic fitness, and may enhance sprint capacity. Therefore, altitude training may confer potentially-beneficial adaptations to team-sport athletes, which have been overlooked in contemporary sport physiology research. Here, we review the current knowledge on the established benefits of altitude training on physiological systems relevant to team-sport performance, and conclude that current evidence supports implementation of altitude training modalities to enhance match physical performances at both sea level and altitude. We hope that this will guide the practice of many athletes and stimulate future research to better refine training programmes.

  15. "Thinking ethics": a novel, pilot, proof-of-concept program of integrating ethics into the Physiology curriculum in South India.

    Science.gov (United States)

    D, Savitha; Vaz, Manjulika; Vaz, Mario

    2017-06-01

    Integrating medical ethics into the physiology teaching-learning program has been largely unexplored in India. The objective of this exercise was to introduce an interactive and integrated ethics program into the Physiology course of first-year medical students and to evaluate their perceptions. Sixty medical students (30 men, 30 women) underwent 11 sessions over a 7-mo period. Two of the Physiology faculty conducted these sessions (20-30 min each) during the routine physiology (theory/practicals) classes that were of shorter duration and could, therefore, accommodate the discussion of related ethical issues. This exercise was in addition to the separate ethics classes conducted by the Medical Ethics department. The sessions were open ended, student centered, and designed to stimulate critical thinking. The students' perceptions were obtained through a semistructured questionnaire and focused group discussions. The students found the program unique, thought provoking, fully integrated, and relevant. It seldom interfered with the physiology teaching. They felt that the program sensitized them about ethical issues and prepared them for their clinical years, to be "ethical doctors." Neutral observers who evaluated each session felt that the integrated program was relevant to the preclinical year and that the program was appropriate in its content, delivery, and student involvement. An ethics course taught in integration with Physiology curriculum was found to be beneficial, feasible, and compatible with Physiology by students as well as neutral observers. Copyright © 2017 the American Physiological Society.

  16. Physiology education in North American dental schools: the basic science survey series.

    Science.gov (United States)

    Gautam, Medha; Shaw, David H; Pate, Ted D; Lambert, H Wayne

    2014-06-01

    As part of the Basic Science Survey Series for Dentistry, members of the American Dental Education Association (ADEA) Physiology, Pharmacology, and Therapeutics Section surveyed directors of physiology courses in North American dental schools. The survey was designed to assess, among other things, faculty affiliation and experience of course directors, teaching methods, general course content and emphasis, extent of interdisciplinary (shared) instruction, and impact of recent curricular changes. Responses were received from forty-four of sixty-seven (65.7 percent) U.S. and Canadian dental schools. The findings suggest the following: substantial variation exists in instructional hours, faculty affiliation, class size, and interdisciplinary nature of physiology courses; physiology course content emphasis is similar between schools; student contact hours in physiology, which have remained relatively stable in the past fifteen years, are starting to be reduced; recent curricular changes have often been directed towards enhancing the integrative and clinically relevant aspects of physiology instruction; and a trend toward innovative content delivery, such as use of computer-assisted instruction, is evident. Data from this study may be useful to physiology course directors, curriculum committees, and other dental educators with an interest in integrative and interprofessional education.

  17. Relevance of collagen piezoelectricity to "Wolff's Law": a critical review.

    Science.gov (United States)

    Ahn, Andrew C; Grodzinsky, Alan J

    2009-09-01

    According to "Wolff's Law", bone is deposited and reinforced at areas of greatest stress. From a clinical perspective, this "law" is supported by the strong association between bone density and physical activity. From a mechanistic standpoint, however, the law presents a challenge to scientists seeking to understand how osteocytes and osteoblasts sense the mechanical load. In the 1960s, collagen piezoelectricity was invoked as a potential mechanism by which osteocytes could detect areas of greater stress but piezoelectricity diminished in importance as more compelling mechanisms, such as streaming potential, were identified. In addition, accumulating evidence for the role of fluid-related shear stress in osteocyte's mechanosensory function has made piezoelectricity seemingly more obsolete in bone physiology. This review critically evaluates the role of collagen piezoelectricity (if any) in Wolff's Law--specifically, the evidence regarding its involvement in strain-generated potentials, existing alternate mechanisms, the present understanding of bone mechanosensation, and whether piezoelectricity serves an influential role within the context of this newly proposed mechanism. In addition to reviewing the literature, this review generates several hypotheses and proposes future research to fully address the relevance of piezoelectricity in bone physiology.

  18. Relevance: An Interdisciplinary and Information Science Perspective

    Directory of Open Access Journals (Sweden)

    Howard Greisdorf

    2000-01-01

    Full Text Available Although relevance has represented a key concept in the field of information science for evaluating information retrieval effectiveness, the broader context established by interdisciplinary frameworks could provide greater depth and breadth to on-going research in the field. This work provides an overview of the nature of relevance in the field of information science with a cursory view of how cross-disciplinary approaches to relevance could represent avenues for further investigation into the evaluative characteristics of relevance as a means for enhanced understanding of human information behavior.

  19. Physiologic profile of professional cricketers.

    Science.gov (United States)

    Johnstone, James A; Ford, Paul A

    2010-11-01

    This study aims to provide a physiologic profile of professional cricketers and note positional differences at the start of the 2007/08 competitive season. Fifteen participants (9 bowlers, 6 batsmen) aged 25.0 ± 5.0 years (mean ± SD) took part in this study. Participants (bowlers and batsmen) completed a series of field-based fitness assessments: body composition (sum of 7 skinfolds, 72.5 ± 16.5 and 65.5 ± 19.3 mm, respectively), flexibility (sit and reach 8.1 ± 10.3 and 6.0 ± 6.2 cm, respectively), predicted maximal oxygen uptake (multistage shuttle run, 54.1 ± 2.8 and 56.1 ± 4.5 ml-1·kg-1·min-1, respectively), upper- (medicine ball throw, 7.7 ± 0.6 and 7.0 ± 0.1 m, respectively) and lower-body strength (countermovement jump, 45.7 ± 5.8 and 43.9 ± 4.1 cm, respectively), speed (sprint 17.7 m, 2.76 ± 0.6 and 2.77 ± 0.1 s, respectively), and explosive power (repeated jump, 31.0 ± 2.0 and 34.1 ± 4.8 cm, respectively). The data provided the physical fitness profile for each player, which, compared with normative data, identified that this cohort of professional cricketers had some superior fitness parameters compared with the general population, and where applicable, were comparable with other professional athletes. In addition, after effect size calculations, the results showed that some physical fitness differences existed between playing positions. Cricket professionals possess a superior level of physical fitness and strength, and conditioning coaches should seek to progress these physical parameters and further identify position-specific physical requirements to progress the modern game.

  20. Physiological factors influencing capillary growth.

    Science.gov (United States)

    Egginton, S

    2011-07-01

    (1) Angiogenesis (growth of new capillaries from an existing capillary bed) may result from a mismatch in microvascular supply and metabolic demand (metabolic error signal). Krogh examined the distribution and number of capillaries to explore the correlation between O(2) delivery and O(2) consumption. Subsequently, the heterogeneity in angiogenic response within a muscle has been shown to reflect either differences in fibre type composition or mechanical load. However, local control leads to targetted angiogenesis in the vicinity of glycolytic fibre types following muscle stimulation, or oxidative fibres following endurance training, while heterogeneity of capillary spacing is maintained during ontogenetic growth. (2) Despite limited microscopy resolution and lack of specific markers, Krogh's interest in the structure of the capillary wall paved the way for understanding the mechanisms of capillary growth. Angiogenesis may be influenced by the response of perivascular or stromal cells (fibroblasts, macrophages and pericytes) to altered activity, likely acting as a source for chemical signals modulating capillary growth such as vascular endothelial growth factor. In addition, haemodynamic factors such as shear stress and muscle stretch play a significant role in adaptive remodelling of the microcirculation. (3) Most indices of capillarity are highly dependent on fibre size, resulting in possible bias because of scaling. To examine the consequences of capillary distribution, it is therefore helpful to quantify the area of tissue supplied by individual capillaries. This allows the spatial limitations inherent in most models of tissue oxygenation to be overcome generating an alternative approach to Krogh's tissue cylinder, the capillary domain, to improve descriptions of intracellular oxygen diffusion. © 2010 The Author. Acta Physiologica © 2010 Scandinavian Physiological Society.

  1. Physiological Bases of Bulimia, and Antidepressant Treatment.

    Science.gov (United States)

    Getzfeld, Andrew R.

    This paper reviews the literature on the physiological causes of bulimia and investigates the rationale behind the usage of antidepressant medication in the treatment of bulimia nervosa. No definite conclusions can be stated regarding the physiology of bulimia, but a number of hypotheses are suggested. It appears that the hypothalamus is involved…

  2. Nigerian Journal of Physiological Sciences: Submissions

    African Journals Online (AJOL)

    The Editor-in-Chief, Nigerian Journal of Physiological Sciences, Department of Physiology ... (c) The page following the title page should contain a brief summary and up to six key words. ... (g) Discussion: Should be related to the results presented. ... should be followed; however references must be kept to a maximum of 10.

  3. Cardiac anatomy and physiology: a review.

    Science.gov (United States)

    Gavaghan, M

    1998-04-01

    This article reviews the normal anatomy and physiology of the heart. Understanding the normal anatomic and physiologic relationships described in this article will help perioperative nurses care for patients who are undergoing cardiac procedures. Such knowledge also assists nurses in educating patients about cardiac procedures and about activities that can prevent, reverse, or improve cardiac illness.

  4. Physiology and biochemistry of honey bees

    Science.gov (United States)

    Despite their tremendous economic importance, honey bees are not a typical model system for studying general questions of insect physiology. This is primarily due to the fact that honey bees live in complex social settings which impact their physiological and biochemical characteristics. Not surpris...

  5. Physiological characteristics of an aging Olympic athlete

    DEFF Research Database (Denmark)

    Nybo, Lars; Schmidt, Jakob Friis; Fritzdorf, Stephen

    2014-01-01

    To investigate the physiological basis of continued world-class performance of a world-class rower who won medals (3 gold and 2 bronze) at five consecutive Olympic Games.......To investigate the physiological basis of continued world-class performance of a world-class rower who won medals (3 gold and 2 bronze) at five consecutive Olympic Games....

  6. Design Projects in Human Anatomy & Physiology

    Science.gov (United States)

    Polizzotto, Kristin; Ortiz, Mary T.

    2008-01-01

    Very often, some type of writing assignment is required in college entry-level Human Anatomy and Physiology courses. This assignment can be anything from an essay to a research paper on the literature, focusing on a faculty-approved topic of interest to the student. As educators who teach Human Anatomy and Physiology at an urban community college,…

  7. Exercise Physiology. Basic Stuff Series I. I.

    Science.gov (United States)

    Svoboda, Milan; And Others

    The fundamentals of exercise physiology (the study of the physiological effects of bodily exertion) form the basis for this booklet designed for teachers of physical education. The scientific principles underlying the building of muscular strength and flexibility are described and illustrated. Topics covered include: (1) muscular strength,…

  8. Anatomy and Physiology of the Small Bowel.

    Science.gov (United States)

    Volk, Neil; Lacy, Brian

    2017-01-01

    Comprehension of small intestine physiology and function provides a framework for the understanding of several important disease pathways of the gastrointestinal system. This article reviews the development, anatomy and histology of the small bowel in addition to physiology and digestion of key nutrients. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Alterations in physiology and anatomy during pregnancy.

    Science.gov (United States)

    Tan, Eng Kien; Tan, Eng Loy

    2013-12-01

    Pregnant women undergo profound anatomical and physiological changes so that they can cope with the increased physical and metabolic demands of their pregnancies. The cardiovascular, respiratory, haematological, renal, gastrointestinal and endocrine systems all undergo important physiological alterations and adaptations needed to allow development of the fetus and to allow the mother and fetus to survive the demands of childbirth. Such alterations in anatomy and physiology may cause difficulties in interpreting signs, symptoms, and biochemical investigations, making the clinical assessment of a pregnant woman inevitably confusing but challenging. Understanding these changes is important for every practicing obstetrician, as the pathological deviations from the normal physiological alterations may not be clear-cut until an adverse outcome has resulted. Only with a sound knowledge of the physiology and anatomy changes can the care of an obstetric parturient be safely optimized for a better maternal and fetal outcome. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. The Effects Of An Exercise Physiology Program on Physical Fitness Variables, Body Satisfaction, and Physiology Knowledge.

    Science.gov (United States)

    Perry, Arlette C.; Rosenblatt, Evelyn S.; Kempner, Lani; Feldman, Brandon B.; Paolercio, Maria A.; Van Bemden, Angie L.

    2002-01-01

    Examined the effects of an exercise physiology program on high school students' physical fitness, body satisfaction, and physiology knowledge. Intervention students received exercise physiology theory and active aerobic and resistance exercise within their biology course. Data from student surveys and measurements indicated that the integrated…

  11. Investor Flows to Asset Managers

    DEFF Research Database (Denmark)

    Christoffersen, Susan E. K.; Musto, David K.; Wermers, Russ

    2014-01-01

    of the financial system and the real economy, and the retirement security and protection of the investors. There is an accordingly large and growing literature on flows that has concentrated on the main retail investment pool, the open-end mutual fund, and has used flows to explore many aspects of retail financial...... decision making. We survey this literature and, where relevant, describe how open-end flows compare to other investment vehicles. We also identify opportunities both for future research and for refinement of mutual fund design, in particular as suggested by the recent rethinking of retail investment pools......Cash flows between investors and funds are both cause and effect in a complex web of economic decisions. Among the issues at stake are the prospects and fees of the funds, the efforts and risk choices by the funds' managers, the pricing and comovement of the assets they trade, the stability...

  12. Visualization and simulation of complex flows in biomedical engineering

    CERN Document Server

    Imai, Yohsuke; Ishikawa, Takuji; Oliveira, Mónica

    2014-01-01

    This book focuses on the most recent advances in the application of visualization and simulation methods to understand the flow behavior of complex fluids used in biomedical engineering and other related fields. It shows the physiological flow behavior in large arteries, microcirculation, respiratory systems and in biomedical microdevices.

  13. Granular flow

    DEFF Research Database (Denmark)

    Mitarai, Namiko; Nakanishi, Hiizu

    2012-01-01

    Granular material is a collection of macroscopic particles that are visible with naked eyes. The non-equilibrium nature of the granular materials makes their rheology quite different from that of molecular systems. In this minireview, we present the unique features of granular materials focusing...... on the shear flow of dry granular materials and granule-liquid mixture....

  14. Does relevance matter in academic policy research

    DEFF Research Database (Denmark)

    Dredge, Dianne

    2015-01-01

    A reflection on whether relevance matters in tourism policy research, and if so, to whom/what should it matter......A reflection on whether relevance matters in tourism policy research, and if so, to whom/what should it matter...

  15. Inoculating Relevance Feedback Against Poison Pills

    NARCIS (Netherlands)

    Dehghani, Mostafa; Azarbonyad, Hosein; Kamps, Jaap; Hiemstra, Djoerd; Marx, Maarten

    2016-01-01

    Relevance Feedback is a common approach for enriching queries, given a set of explicitly or implicitly judged documents to improve the performance of the retrieval. Although it has been shown that on average, the overall performance of retrieval will be improved after relevance feedback, for some

  16. Relevant cost information for order acceptance decisions

    NARCIS (Netherlands)

    Wouters, M.J.F.

    1997-01-01

    Some economic considerations for order acceptance decisions are discussed. The relevant economic considerations for order acceptance are widely discussed in the literature: only those costs are relevant which would be avoidable by not accepting the order incremental costs plus opportunity costs .

  17. Android Smartphone Relevance to Military Weather Applications

    Science.gov (United States)

    2011-10-01

    lithium -ion battery that may be replaced by the user (unlike Apple iPod Touch devices), thus spare batteries can be carried. If there is only sporadic...Android Smartphone Relevance to Military Weather Applications by David Sauter ARL-TR-5793 October 2011...Android Smartphone Relevance to Military Weather Applications David Sauter Computational and Information Sciences Directorate, ARL

  18. Using small XML elements to support relevance

    NARCIS (Netherlands)

    G. Ramirez Camps (Georgina); T.H.W. Westerveld (Thijs); A.P. de Vries (Arjen)

    2006-01-01

    htmlabstractSmall XML elements are often estimated relevant by the retrieval model but they are not desirable retrieval units. This paper presents a generic model that exploits the information obtained from small elements. We identify relationships between small and relevant elements and use this

  19. Translation as secondary communication. The relevance theory ...

    African Journals Online (AJOL)

    Ernst-August Gutt started one of the greatest translation debates of the past ten years when he suggested that relevance theory holds the key to providing a unified account of translation. The bulk of the debate has been between practitioners of functional equivalence and advocates of a relevance theoretic approach to ...

  20. Evolutionary relevance facilitates visual information processing.

    Science.gov (United States)

    Jackson, Russell E; Calvillo, Dusti P

    2013-11-03

    Visual search of the environment is a fundamental human behavior that perceptual load affects powerfully. Previously investigated means for overcoming the inhibitions of high perceptual load, however, generalize poorly to real-world human behavior. We hypothesized that humans would process evolutionarily relevant stimuli more efficiently than evolutionarily novel stimuli, and evolutionary relevance would mitigate the repercussions of high perceptual load during visual search. Animacy is a significant component to evolutionary relevance of visual stimuli because perceiving animate entities is time-sensitive in ways that pose significant evolutionary consequences. Participants completing a visual search task located evolutionarily relevant and animate objects fastest and with the least impact of high perceptual load. Evolutionarily novel and inanimate objects were located slowest and with the highest impact of perceptual load. Evolutionary relevance may importantly affect everyday visual information processing.

  1. Evolutionary Relevance Facilitates Visual Information Processing

    Directory of Open Access Journals (Sweden)

    Russell E. Jackson

    2013-07-01

    Full Text Available Visual search of the environment is a fundamental human behavior that perceptual load affects powerfully. Previously investigated means for overcoming the inhibitions of high perceptual load, however, generalize poorly to real-world human behavior. We hypothesized that humans would process evolutionarily relevant stimuli more efficiently than evolutionarily novel stimuli, and evolutionary relevance would mitigate the repercussions of high perceptual load during visual search. Animacy is a significant component to evolutionary relevance of visual stimuli because perceiving animate entities is time-sensitive in ways that pose significant evolutionary consequences. Participants completing a visual search task located evolutionarily relevant and animate objects fastest and with the least impact of high perceptual load. Evolutionarily novel and inanimate objects were located slowest and with the highest impact of perceptual load. Evolutionary relevance may importantly affect everyday visual information processing.

  2. Kernel-Based Relevance Analysis with Enhanced Interpretability for Detection of Brain Activity Patterns

    Directory of Open Access Journals (Sweden)

    Andres M. Alvarez-Meza

    2017-10-01

    Full Text Available We introduce Enhanced Kernel-based Relevance Analysis (EKRA that aims to support the automatic identification of brain activity patterns using electroencephalographic recordings. EKRA is a data-driven strategy that incorporates two kernel functions to take advantage of the available joint information, associating neural responses to a given stimulus condition. Regarding this, a Centered Kernel Alignment functional is adjusted to learning the linear projection that best discriminates the input feature set, optimizing the required free parameters automatically. Our approach is carried out in two scenarios: (i feature selection by computing a relevance vector from extracted neural features to facilitating the physiological interpretation of a given brain activity task, and (ii enhanced feature selection to perform an additional transformation of relevant features aiming to improve the overall identification accuracy. Accordingly, we provide an alternative feature relevance analysis strategy that allows improving the system performance while favoring the data interpretability. For the validation purpose, EKRA is tested in two well-known tasks of brain activity: motor imagery discrimination and epileptic seizure detection. The obtained results show that the EKRA approach estimates a relevant representation space extracted from the provided supervised information, emphasizing the salient input features. As a result, our proposal outperforms the state-of-the-art methods regarding brain activity discrimination accuracy with the benefit of enhanced physiological interpretation about the task at hand.

  3. Functional relevance of water and glycerol channels in Saccharomyces cerevisiae.

    Science.gov (United States)

    Sabir, Farzana; Loureiro-Dias, Maria C; Soveral, Graça; Prista, Catarina

    2017-05-01

    Our understanding of the functional relevance of orthodox aquaporins and aquaglyceroporins in Saccharomyces cerevisiae is essentially based on phenotypic variations obtained by expression/overexpression/deletion of these major intrinsic proteins in selected strains. These water/glycerol channels are considered crucial during various life-cycle phases, such as sporulation and mating and in some life processes such as rapid freeze-thaw tolerance, osmoregulation and phenomena associated with cell surface. Despite their putative functional roles not only as channels but also as sensors, their underlying mechanisms and their regulation are still poorly understood. In the present review, we summarize and discuss the physiological relevance of S. cerevisiae aquaporins (Aqy1 and Aqy2) and aquaglyceroporins (Fps1 and Yfl054c). In particular, the fact that most S. cerevisiae laboratory strains harbor genes coding for non-functional aquaporins, while wild and industrial strains possess at least one functional aquaporin, suggests that aquaporin activity is required for cell survival under more harsh conditions. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  4. Industrial Relevance of Chromosomal Copy Number Variation in Saccharomyces Yeasts.

    Science.gov (United States)

    Gorter de Vries, Arthur R; Pronk, Jack T; Daran, Jean-Marc G

    2017-06-01

    Chromosomal copy number variation (CCNV) plays a key role in evolution and health of eukaryotes. The unicellular yeast Saccharomyces cerevisiae is an important model for studying the generation, physiological impact, and evolutionary significance of CCNV. Fundamental studies of this yeast have contributed to an extensive set of methods for analyzing and introducing CCNV. Moreover, these studies provided insight into the balance between negative and positive impacts of CCNV in evolutionary contexts. A growing body of evidence indicates that CCNV not only frequently occurs in industrial strains of Saccharomyces yeasts but also is a key contributor to the diversity of industrially relevant traits. This notion is further supported by the frequent involvement of CCNV in industrially relevant traits acquired during evolutionary engineering. This review describes recent developments in genome sequencing and genome editing techniques and discusses how these offer opportunities to unravel contributions of CCNV in industrial Saccharomyce s strains as well as to rationally engineer yeast chromosomal copy numbers and karyotypes. Copyright © 2017 Gorter de Vries et al.

  5. Earnings Management, Value Relevance Of Earnings and Book Value of Equity

    OpenAIRE

    Subekti, Imam

    2013-01-01

    Previous studies examining relationship between earnings management and value relevance of accounting information show that earnings management decrease value relevance of accounting information. Generally, the studies apply accruals earnings management. In contrast, the present study applies integrated earnings management proxies i.e. real and accruals earnings manage-ment. Real earnings management proxies are measured by abnormal cash flow of operation, ab-normal production cost, and abnorm...

  6. Quantitative Circulatory Physiology: an integrative mathematical model of human physiology for medical education.

    Science.gov (United States)

    Abram, Sean R; Hodnett, Benjamin L; Summers, Richard L; Coleman, Thomas G; Hester, Robert L

    2007-06-01

    We have developed Quantitative Circulatory Physiology (QCP), a mathematical model of integrative human physiology containing over 4,000 variables of biological interactions. This model provides a teaching environment that mimics clinical problems encountered in the practice of medicine. The model structure is based on documented physiological responses within peer-reviewed literature and serves as a dynamic compendium of physiological knowledge. The model is solved using a desktop, Windows-based program, allowing students to calculate time-dependent solutions and interactively alter over 750 parameters that modify physiological function. The model can be used to understand proposed mechanisms of physiological function and the interactions among physiological variables that may not be otherwise intuitively evident. In addition to open-ended or unstructured simulations, we have developed 30 physiological simulations, including heart failure, anemia, diabetes, and hemorrhage. Additional stimulations include 29 patients in which students are challenged to diagnose the pathophysiology based on their understanding of integrative physiology. In summary, QCP allows students to examine, integrate, and understand a host of physiological factors without causing harm to patients. This model is available as a free download for Windows computers at http://physiology.umc.edu/themodelingworkshop.

  7. Social isolation induces behavioral and neuroendocrine disturbances relevant to depression in female and male prairie voles

    OpenAIRE

    Grippo, Angela J.; Gerena, Davida; Huang, Jonathan; Kumar, Narmda; Shah, Maulin; Ughreja, Raj; Carter, C. Sue

    2007-01-01

    Supportive social interactions may be protective against stressors and certain mental and physical illness, while social isolation may be a powerful stressor. Prairie voles are socially monogamous rodents that model some of the behavioral and physiological traits displayed by humans, including sensitivity to social isolation. Neuroendocrine and behavioral parameters, selected for their relevance to stress and depression, were measured in adult female and male prairie voles following 4 weeks o...

  8. Conservation physiology can inform threat assessment and recovery planning processes for threatened species

    DEFF Research Database (Denmark)

    Birnie-Gauvin, Kim; Walton, Sarah; Delle Palme, Caleigh A.

    2017-01-01

    threat assessments and work with partners to develop recovery plans. Here we argue that conservation physiology has much to offer for the threat assessment process and outline the ways in which this can be operationalized. For instance, conservation physiology is effective at revealing causal...... role in the conservation activities of bodies like the IUCN that are engaged in threat assessment and recovery of endangered organisms. Although we focus on activities at the international scale, these same concepts are relevant and applicable to national and regional bodies...

  9. Flow Game

    DEFF Research Database (Denmark)

    Olsen, Jesper Lind

    2003-01-01

    Flow Game er et dialogspil, der kan bruges som ledelsesværktøj, ledertræning, samtaletræning, coachingtræning og ideudvikling m.m. Gennem dilemmakort provokeres en dialog og teori-U inspireret afklaring- og udviklingsproces, hvor der enten arbejdes på en gruppes eller et individs vision/innovatio......Flow Game er et dialogspil, der kan bruges som ledelsesværktøj, ledertræning, samtaletræning, coachingtræning og ideudvikling m.m. Gennem dilemmakort provokeres en dialog og teori-U inspireret afklaring- og udviklingsproces, hvor der enten arbejdes på en gruppes eller et individs vision...

  10. Media Flow

    DEFF Research Database (Denmark)

    Kabel, Lars

    2016-01-01

    News and other kinds of journalistic stories, 16-17 hours a day, all year round, on all platforms, also the moderated social media. The key research thesis behind this article is that the continuous and speedy stream of news stories and media content now is becoming the centre of the production...... processes and the value creation in converged multimedia newsrooms. The article identify new methods and discuss editorial challenges in handling media flow....

  11. ANALYSIS AND ACCOUNTING OF TOTAL CASH FLOW

    Directory of Open Access Journals (Sweden)

    MELANIA ELENA MICULEAC

    2012-01-01

    Full Text Available In order to reach the objective of supplying some relevant information regarding the liquidity inflows and outflows during a financial exercise, the total cash flow analysis must include the analysis of result cashable from operation, of payments and receipts related to the investment and of financing decisions of the last exercise, as well as the analysis of treasury variation (of cash items. The management of total cash flows ensures the correlation of current liquidness flows as consequence of receipts with the payments ’flows, in order to provide payment continuity of mature obligations.

  12. Astrophysical relevance of γ transition energies

    International Nuclear Information System (INIS)

    Rauscher, Thomas

    2008-01-01

    The relevant γ energy range is explicitly identified where additional γ strength must be located to have an impact on astrophysically relevant reactions. It is shown that folding the energy dependences of the transmission coefficients and the level density leads to maximal contributions for γ energies of 2≤E γ ≤4 unless quantum selection rules allow isolated states to contribute. Under this condition, electric dipole transitions dominate. These findings allow us to more accurately judge the relevance of modifications of the γ strength for astrophysics

  13. Neutrophil programming dynamics and its disease relevance.

    Science.gov (United States)

    Ran, Taojing; Geng, Shuo; Li, Liwu

    2017-11-01

    Neutrophils are traditionally considered as first responders to infection and provide antimicrobial host defense. However, recent advances indicate that neutrophils are also critically involved in the modulation of host immune environments by dynamically adopting distinct functional states. Functionally diverse neutrophil subsets are increasingly recognized as critical components mediating host pathophysiology. Despite its emerging significance, molecular mechanisms as well as functional relevance of dynamically programmed neutrophils remain to be better defined. The increasing complexity of neutrophil functions may require integrative studies that address programming dynamics of neutrophils and their pathophysiological relevance. This review aims to provide an update on the emerging topics of neutrophil programming dynamics as well as their functional relevance in diseases.

  14. Bone blood flow and metabolism in humans

    DEFF Research Database (Denmark)

    Heinonen, Ilkka; Kemppainen, Jukka; Kaskinoro, Kimmo

    2012-01-01

    Human bone blood flow and metabolism during physical exercise remains poorly characterised. In the present study we measured femoral bone blood flow and glucose uptake in young healthy subjects by positron emission tomography in three separate protocols. In six women, blood flow was measured...... in femoral bone at rest and during one leg intermittent isometric exercise with increasing exercise intensities. In nine men, blood flow in femur was determined at rest and during dynamic one leg exercise, and two other physiological perturbations: moderate systemic hypoxia (14 O(2) ) at rest and during...... exercise, and during intra-femoral infusion of high-dose adenosine. Bone glucose uptake was measured at rest and during dynamic one leg exercise in five men. The results indicate that isometric exercise increased femoral bone blood flow from rest (1.8 ± 0.6 ml/100g/min) to low intensity exercise (4.1 ± 1...

  15. Blood cell interactions and segregation in flow.

    Science.gov (United States)

    Munn, Lance L; Dupin, Michael M

    2008-04-01

    For more than a century, pioneering researchers have been using novel experimental and computational approaches to probe the mysteries of blood flow. Thanks to their efforts, we know that blood cells generally prefer to migrate to the axis of flow, that red and white cells segregate in flow, and that cell deformability and their tendency to reversibly aggregate contribute to the non-Newtonian nature of this unique fluid. All of these properties have beneficial physiological consequences, allowing blood to perform a variety of critical functions. Our current understanding of these unusual flow properties of blood have been made possible by the ingenuity and diligence of a number of researchers, including Harry Goldsmith, who developed novel technologies to visualize and quantify the flow of blood at the level of individual cells. Here we summarize efforts in our lab to continue this tradition and to further our understanding of how blood cells interact with each other and with the blood vessel wall.

  16. Morphological, physiological and biochemical studies on Pyricularia ...

    African Journals Online (AJOL)

    SARAH

    2014-02-28

    Feb 28, 2014 ... compounds seem to reflect inherent biochemical and physiological differences among P. grisea isolates .... solutions for imaging and microscopy, soft image system .... characteristics among 12 P. grisea isolates from rice were.

  17. Automatic duress alarms through physiological response monitoring

    International Nuclear Information System (INIS)

    Roehrig, S.C.

    1977-07-01

    Physiological response monitoring under controlled conditions can provide an effective means for passively determining if the wearer is under moderate to severe stresses. By monitoring the heart rate (HR) and galvanic skin response (GSR) of an individual, it is possible to detect in real time the increase in heart rate and GSR levels due to physiological reactions to mental duress. With existing physiological monitoring equipment, however, the work load of the wearer must be well defined since it is impossible, without additional data, to distinguish mental duress responses from those resulting from moderate physical exertion. Similarly, environmental conditions should be constrained within set limits to avoid masking increases in GSR levels due to metntal stress from those associated with increased perspiration. These constraints should not prove overly restrictive and would allow an integrated security system utilizing physiological monitoring equipment to provide an effective real time, automated early warning system for detection of mental duress or death of the wearer

  18. Reproductive physiology of the male camelid.

    Science.gov (United States)

    Bravo, P W; Johnson, L W

    1994-07-01

    The physiology of reproduction with emphasis on endocrinology of llamas and alpacas is addressed. Information regarding male anatomy, puberty, testicular function, semen description, and sexual behavior is also included.

  19. SOME PSYCHO CULTURAL AND PHYSIOLOGICAL FACTORS AS ...

    African Journals Online (AJOL)

    Admin

    This study sought to find out the extent to which some psycho cultural and ... psycho cultural and physiological variables (gender, age, traditional beliefs about ..... (Ed.) Confronting the AIDS Epidemic, ... Counselling Psychology, 6 (1): 39-57.

  20. Physiological responses induced by pleasant stimuli.

    Science.gov (United States)

    Watanuki, Shigeki; Kim, Yeon-Kyu

    2005-01-01

    The specific physiological responses induced by pleasant stimuli were investigated in this study. Various physiological responses of the brain (encephaloelectrogram; EEG), autonomic nervous system (ANS), immune system and endocrine system were monitored when pleasant stimuli such as odors, emotional pictures and rakugo, a typical Japanese comical story-telling, were presented to subjects. The results revealed that (i) EEG activities of the left frontal brain region were enhanced by a pleasant odor; (ii) emotional pictures related to primitive element such as nudes and erotic couples elevated vasomotor sympathetic nervous activity; and (iii) an increase in secretory immunoglobulin A (s-IgA) and a decrease in salivary cortisol (s-cortisol) were induced by rakugo-derived linguistic pleasant emotion. Pleasant emotion is complicated state. However, by considering the evolutionary history of human being, it is possible to assess and evaluate pleasant emotion from certain physiological responses by appropriately summating various physiological parameters.