WorldWideScience

Sample records for saturation pressure differences

  1. Effect of Saturation Pressure Difference on Metal–Silicide Nanopowder Formation in Thermal Plasma Fabrication

    Directory of Open Access Journals (Sweden)

    Masaya Shigeta

    2016-03-01

    Full Text Available A computational investigation using a unique model and a solution algorithm was conducted, changing only the saturation pressure of one material artificially during nanopowder formation in thermal plasma fabrication, to highlight the effects of the saturation pressure difference between a metal and silicon. The model can not only express any profile of particle size–composition distribution for a metal–silicide nanopowder even with widely ranging sizes from sub-nanometers to a few hundred nanometers, but it can also simulate the entire growth process involving binary homogeneous nucleation, binary heterogeneous co-condensation, and coagulation among nanoparticles with different compositions. Greater differences in saturation pressures cause a greater time lag for co-condensation of two material vapors during the collective growth of the metal–silicide nanopowder. The greater time lag for co-condensation results in a wider range of composition of the mature nanopowder.

  2. Experimental study and theoretical interpretation of saturation effect on ultrasonic velocity in tight sandstones under different pressure conditions

    Science.gov (United States)

    Li, Dongqing; Wei, Jianxin; Di, Bangrang; Ding, Pinbo; Huang, Shiqi; Shuai, Da

    2018-03-01

    Understanding the influence of lithology, porosity, permeability, pore structure, fluid content and fluid distribution on the elastic wave properties of porous rocks is of great significance for seismic exploration. However, unlike conventional sandstones, the petrophysical characteristics of tight sandstones are more complex and less understood. To address this problem, we measured ultrasonic velocity in partially saturated tight sandstones under different effective pressures. A new model is proposed, combining the Mavko-Jizba-Gurevich relations and the White model. The proposed model can satisfactorily simulate and explain the saturation dependence and pressure dependence of velocity in tight sandstones. Under low effective pressure, the relationship of P-wave velocity to saturation is pre-dominantly attributed to local (pore scale) fluid flow and inhomogeneous pore-fluid distribution (large scale). At higher effective pressure, local fluid flow gradually decreases, and P-wave velocity gradually shifts from uniform saturation towards patchy saturation. We also find that shear modulus is more sensitive to saturation at low effective pressures. The new model includes wetting ratio, an adjustable parameter that is closely related to the relationship between shear modulus and saturation.

  3. Using X-ray computed tomography to evaluate the initial saturation resulting from different saturation procedures

    DEFF Research Database (Denmark)

    Christensen, Britt Stenhøj Baun; Wildenschild, D; Jensen, K.H.

    2006-01-01

    for saturation. Evaluation of the different enhanced saturation techniques was done with Xray computed tomography (CT) and gravimetrically. The use of CT scanning makes it possible to observe the spatial distribution of wetting and non-wetting phases in the porous medium in a non-destructive way. In this case...... with pressurized nitrogen between each saturation and allowed to saturate for the same length of time for all the different procedures. Both gravimetric measurements and CT attenuation levels showed that venting the sample with carbon dioxide prior to saturation clearly improved initial saturation whereas the use...

  4. On the propagation of a coupled saturation and pressure front

    Energy Technology Data Exchange (ETDEWEB)

    Vasco, D. W.

    2010-12-01

    Using an asymptotic technique, valid for a medium with smoothly varying heterogeneity, I derive an expression for the velocity of a propagating, coupled saturation and pressure front. Due to the nonlinearity of the governing equations, the velocity of the propagating front depends upon the magnitude of the saturation and pressure changes across the front in addition to the properties of the medium. Thus, the expression must be evaluated in conjunction with numerical reservoir simulation. The propagation of the two-phase front is governed by the background saturation distribution, the saturation-dependent component of the fluid mobility, the porosity, the permeability, the capillary pressure function, the medium compressibility, and the ratio of the slopes of the relative permeability curves. Numerical simulation of water injection into a porous layer saturated with a nonaqueous phase liquid indicates that two modes of propagation are important. The fastest mode of propagation is a pressure-dominated disturbance that travels through the saturated layer. This is followed, much later, by a coupled mode with a large saturation change. These two modes are also observed in a simulation using a heterogeneous porous layer. A comparison between the propagation times estimated from the results of the numerical simulation and predictions from the asymptotic expression indicates overall agreement.

  5. Atmospheric sugar alcohols: evaporation rates and saturation vapor pressures

    DEFF Research Database (Denmark)

    Bilde, Merete; Zardini, Alessandro Alessio; Hong, Juan

    volatile organic molecules. Saturation vapor pressure and the associated temperature dependence (dH) are key parameters for improving predictive atmospheric models. In this work we combine experiments and thermodynamic modeling to investigate these parameters for a series of polyols, so-called sugar...... are allowed to evaporate in a laminar flow reactor, and changes in particle size as function of evaporation time are determined using a scanning mobility particle sizer system. In this work saturation vapor pressures of sugar alcohols at several temperatures have been inferred from such measurements using...

  6. Simulation of coupled flow and mechanical deformation using IMplicit Pressure-Displacement Explicit Saturation (IMPDES) scheme

    KAUST Repository

    El-Amin, Mohamed

    2012-01-01

    The problem of coupled structural deformation with two-phase flow in porous media is solved numerically using cellcentered finite difference (CCFD) method. In order to solve the system of governed partial differential equations, the implicit pressure explicit saturation (IMPES) scheme that governs flow equations is combined with the the implicit displacement scheme. The combined scheme may be called IMplicit Pressure-Displacement Explicit Saturation (IMPDES). The pressure distribution for each cell along the entire domain is given by the implicit difference equation. Also, the deformation equations are discretized implicitly. Using the obtained pressure, velocity is evaluated explicitly, while, using the upwind scheme, the saturation is obtained explicitly. Moreover, the stability analysis of the present scheme has been introduced and the stability condition is determined.

  7. Arterial blood oxygen saturation during blood pressure cuff-induced hypoperfusion

    Energy Technology Data Exchange (ETDEWEB)

    Kyriacou, P A [School of Engineering and Mathematical Sciences, City University, London EC1V 0HB (United Kingdom); Shafqat, K [School of Engineering and Mathematical Sciences, City University, London EC1V 0HB (United Kingdom); Pal, S K [St Andrew' s Centre for Plastic Surgery and Burns, Broomfield Hospital, Chelmsford, CM1 7ET (United Kingdom)

    2007-10-15

    Pulse oximetry has been one of the most significant technological advances in clinical monitoring in the last two decades. Pulse oximetry is a non-invasive photometric technique that provides information about the arterial blood oxygen saturation (SpO{sub 2}) and heart rate, and has widespread clinical applications. When peripheral perfusion is poor, as in states of hypovolaemia, hypothermia and vasoconstriction, oxygenation readings become unreliable or cease. The problem arises because conventional pulse oximetry sensors must be attached to the most peripheral parts of the body, such as finger, ear or toe, where pulsatile flow is most easily compromised. Pulse oximeters estimate arterial oxygen saturation by shining light at two different wavelengths, red and infrared, through vascular tissue. In this method the ac pulsatile photoplethysmographic (PPG) signal associated with cardiac contraction is assumed to be attributable solely to the arterial blood component. The amplitudes of the red and infrared ac PPG signals are sensitive to changes in arterial oxygen saturation because of differences in the light absorption of oxygenated and deoxygenated haemoglobin at these two wavelengths. From the ratios of these amplitudes, and the corresponding dc photoplethysmographic components, arterial blood oxygen saturation (SpO{sub 2}) is estimated. Hence, the technique of pulse oximetry relies on the presence of adequate peripheral arterial pulsations, which are detected as photoplethysmographic (PPG) signals. The aim of this study was to investigate the effect of pressure cuff-induced hypoperfusion on photoplethysmographic signals and arterial blood oxygen saturation using a custom made finger blood oxygen saturation PPG/SpO{sub 2} sensor and a commercial finger pulse oximeter. Blood oxygen saturation values from the custom oxygen saturation sensor and a commercial finger oxygen saturation sensor were recorded from 14 healthy volunteers at various induced brachial pressures

  8. An innovative technique for estimating water saturation from capillary pressure in clastic reservoirs

    Science.gov (United States)

    Adeoti, Lukumon; Ayolabi, Elijah Adebowale; James, Logan

    2017-11-01

    A major drawback of old resistivity tools is the poor vertical resolution and estimation of hydrocarbon when applying water saturation (Sw) from historical resistivity method. In this study, we have provided an alternative method called saturation height function to estimate hydrocarbon in some clastic reservoirs in the Niger Delta. The saturation height function was derived from pseudo capillary pressure curves generated using modern wells with complete log data. Our method was based on the determination of rock type from log derived porosity-permeability relationship, supported by volume of shale for its classification into different zones. Leverette-J functions were derived for each rock type. Our results show good correlation between Sw from resistivity based method and Sw from pseudo capillary pressure curves in wells with modern log data. The resistivity based model overestimates Sw in some wells while Sw from the pseudo capillary pressure curves validates and predicts more accurate Sw. In addition, the result of Sw from pseudo capillary pressure curves replaces that of resistivity based model in a well where the resistivity equipment failed. The plot of hydrocarbon pore volume (HCPV) from J-function against HCPV from Archie shows that wells with high HCPV have high sand qualities and vice versa. This was further used to predict the geometry of stratigraphic units. The model presented here freshly addresses the gap in the estimation of Sw and is applicable to reservoirs of similar rock type in other frontier basins worldwide.

  9. Pressure difference receiving ears

    DEFF Research Database (Denmark)

    Michelsen, Axel; Larsen, Ole Næsbye

    2007-01-01

    waves behave in the air spaces leading to the interior surfaces of eardrums. A linear mathematical model with well-defined inputs is used for exploring how the directionality varies with the binaural directional cues and the amplitude and phase gain of the sound pathway to the inner surface...... of such pressure difference receiving ears have been hampered by lack of suitable experimental methods. In this review, we review the methods for collecting reliable data on the binaural directional cues at the eardrums, on how the eardrum vibrations depend on the direction of sound incidence, and on how sound...

  10. Pore Pressure Response to Groundwater Fluctuations in Saturated Double-Layered Soil

    Directory of Open Access Journals (Sweden)

    Hongwei Ying

    2015-01-01

    Full Text Available Analytical solutions are developed for one-dimensional consolidation of double-layered saturated soil subjected to groundwater fluctuations. The solutions are derived by an explicit mathematical procedure using Duhamel’s theorem in conjunction with a Fourier series, when groundwater fluctuation is described by a general time-dependent function and assumed to be the pore water pressure variations at the upper boundary. Taking as an example the harmonic groundwater fluctuation, the relevant response of the excess pore water pressure is discussed in detail, and the main influencing factors of the excess pore pressure distribution are analyzed. A dimensionless parameter θ has been introduced because it significantly affects the phase and the amplitude of excess pore pressures. The influences of the coefficients of permeability and compressibility of soil on the excess pore pressure distribution are different and cannot be incorporated into the coefficient of consolidation in double-layered soil. The relative permeability ratio of two clayey soils also plays an important role on the curves of the distributions of the excess pore pressures. The effects of the thickness of the soil layer on the excess pore pressure distribution should be considered together with the dimensionless parameter θ and the permeability and compressibility of the double-layered soil system.

  11. Saturated virtual fluorescence emission difference microscopy based on detector array

    Science.gov (United States)

    Liu, Shaocong; Sun, Shiyi; Kuang, Cuifang; Ge, Baoliang; Wang, Wensheng; Liu, Xu

    2017-07-01

    Virtual fluorescence emission difference microscopy (vFED) has been proposed recently to enhance the lateral resolution of confocal microscopy with a detector array, implemented by scanning a doughnut-shaped pattern. Theoretically, the resolution can be enhanced by around 1.3-fold compared with that in confocal microscopy. For further improvement of the resolving ability of vFED, a novel method is presented utilizing fluorescence saturation for super-resolution imaging, which we called saturated virtual fluorescence emission difference microscopy (svFED). With a point detector array, matched solid and hollow point spread functions (PSF) can be obtained by photon reassignment, and the difference results between them can be used to boost the transverse resolution. Results show that the diffraction barrier can be surpassed by at least 34% compared with that in vFED and the resolution is around 2-fold higher than that in confocal microscopy.

  12. Measuring Negative Pore Pressures in Partially Frozen Saturated Soils

    OpenAIRE

    Holten, Johannes Gaspar

    2017-01-01

    Freezing of soil is an issue which has many implications on modern infrastructure, in which frost heave plays a pivotal role. During freezing the behavior of the soil and the flow of water is altered. In an engineering perspective, it is important to grasp the driving forces behind these behavioral changes. The main contributor to frost heave is the development of a large negative pore pressure in the unfrozen water in partially frozen fine-grained soil, termed cryosuction. The suction leads...

  13. Capillary pressure-saturation relationships for diluted bitumen and water in gravel

    Science.gov (United States)

    Hossain, S. Zubair; Mumford, Kevin G.

    2017-08-01

    Spills of diluted bitumen (dilbit) to rivers by rail or pipeline accidents can have serious long-term impacts on environment and ecology due to the submergence and trapping of oil within the river bed sediment. The extent of this problem is dictated by the amount of immobile oil available for mass transfer into the water flowing through the sediment pores. An understanding of multiphase (oil and water) flow in the sediment, including oil trapping by hysteretic drainage and imbibition, is important for the development of spill response and risk assessment strategies. Therefore, the objective of this study was to measure capillary pressure-saturation (Pc-Sw) relationships for dilbit and water, and air and water in gravel using a custom-made pressure cell. The Pc-Sw relationships obtained using standard procedures in coarse porous media are height-averaged and often require correction. By developing and comparing air-water and dilbit-water Pc-Sw curves, it was found that correction was less important in dilbit-water systems due to the smaller difference in density between the fluids. In both systems, small displacement pressures were needed for the entry of non-wetting fluid in gravel. Approximately 14% of the pore space was occupied by trapped dilbit after imbibition, which can serve as a source of long-term contamination. While air-water data can be scaled to reasonably predict dilbit-water behaviour, it cannot be used to determine the trapped amount.

  14. Indoor/outdoor connections exemplified by processes that depend on an organic compound's saturation vapor pressure

    DEFF Research Database (Denmark)

    Weschler, Charles J.

    2003-01-01

    Outdoor and indoor environments are profitably viewed as parts of a whole connected through various physical and chemical interactions. This paper examines four phenomena that share a dependence on vapor pressure-the extent to which an organic compound in the gas phase sorbs on airborne particles...... first estimates of the above processes. For typical indoor conditions, only larger compounds with lower-saturation vapor pressures (e.g., tetracosane, pentacosane, or di-2-ethylhexyl phthalate) have airborne particle concentrations comparable to or larger than gas phase concentrations. Regardless......'s saturation vapor pressure correlates in a linear fashion with the logarithms of equilibrium coefficients characteristic of each of these four phenomena. Since, to a rough approximation, the log of an organic compound's vapor pressure scales with its molecular weight, molecular weight can be used to make...

  15. Ligand screening by saturation-transfer difference (STD) NMR spectroscopy.

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, V V

    2005-04-26

    NMR based methods to screen for high-affinity ligands have become an indispensable tool for designing rationalized drugs, as these offer a combination of good experimental design of the screening process and data interpretation methods, which together provide unprecedented information on the complex nature of protein-ligand interactions. These methods rely on measuring direct changes in the spectral parameters, that are often simpler than the complex experimental procedures used to study structure and dynamics of proteins. The goal of this review article is to provide the basic details of NMR based ligand-screening methods, with particular focus on the saturation transfer difference (STD) experiment. In addition, we provide an overview of other NMR experimental methods and a practical guide on how to go about designing and implementing them.

  16. Impact of sample geometry on the measurement of pressure-saturation curves: Experiments and simulations

    Science.gov (United States)

    Moura, M.; Fiorentino, E.-A.; Mâløy, K. J.; Schäfer, G.; Toussaint, R.

    2015-11-01

    In this paper, we study the influence of sample geometry on the measurement of pressure-saturation relationships, by analyzing the drainage of a two-phase flow from a quasi-2-D random porous medium. The medium is transparent, which allows for the direct visualization of the invasion pattern during flow, and is initially saturated with a viscous liquid (a dyed glycerol-water mix). As the pressure in the liquid is gradually reduced, air penetrates from an open inlet, displacing the liquid which leaves the system from an outlet on the opposite side. Pressure measurements and images of the flow are recorded and the pressure-saturation relationship is computed. We show that this relationship depends on the system size and aspect ratio. The effects of the system's boundaries on this relationship are measured experimentally and compared with simulations produced using an invasion percolation algorithm. The pressure build up at the beginning and end of the invasion process are particularly affected by the boundaries of the system whereas at the central part of the model (when the air front progresses far from these boundaries), the invasion happens at a statistically constant capillary pressure. These observations have led us to propose a much simplified pressure-saturation relationship, valid for systems that are large enough such that the invasion is not influenced by boundary effects. The properties of this relationship depend on the capillary pressure thresholds distribution, sample dimensions, and average pore connectivity and its applications may be of particular interest for simulations of two-phase flow in large porous media.

  17. Capillary pressure as a unique function of electric permittivity and water saturation

    NARCIS (Netherlands)

    Plug, W.J.; Slob, E.; Van Turnhout, J.; Bruining, J.

    2007-01-01

    The relation between capillary pressure (Pc) and interfacial area has been investigated by measuring Pc and the electric permittivity at 100 kHz simultaneously as function of the water saturation, (Sw). Drainage and imbibition experiments have been conducted for sand-distilled water-gas (CO2/N2)

  18. Applying of modern approach to evaluation of initial hydrocarbon reserves at the edge of saturation pressure

    Directory of Open Access Journals (Sweden)

    Віталій Ігорович Коваль

    2016-07-01

    Full Text Available The article deals the features for evaluation of initial saturated hydrocarbon reserves, which developed as the depletion of reservoir energy and the maintenance of reservoir pressure. A new method of material balance is used with accounting of the gravity distribution of reservoir system components, extraction of each component of reservoir fluids, change of their physical properties in the development of deposits

  19. Changes in Tissue Oxygen Saturation in Response to Different Calf Compression Sleeves

    Science.gov (United States)

    Dermont, T.; Morizot, L.; Bouhaddi, M.; Ménétrier, A.

    2015-01-01

    Aim. The purpose was to examine the changes in tissue oxygen saturation (StO2) in response to the application of different commercially available calf compression sleeves. Methods. Eight subjects came to the laboratory to complete a session in seated position including 10 min of quiet rest followed by 3 min measuring calf StO2 without compression sleeves and then alternating of 3 min of passive rest and 3 min measuring StO2 with calf compression sleeves. A total of 15 different commercially available compression sleeves were studied in a randomized order. Calf StO2 was recorded using near-infrared spectroscopy. Results. StO2 was significantly increased with all compression sleeves (p < 0.05) compared with no compression (from +6.9% for the least effective to +22.6% for the most effective). Large differences were observed between compression sleeves (p < 0.05). StO2 was positively correlated with compression pressure (p < 0.05; r = 0.84). Conclusion. This study shows that wearing compression sleeves from various brands differently affects tissue oxygen saturation. Differences were linked to the compression pressure: higher compression pressures were associated with higher StO2. PMID:26464899

  20. Network model investigation of interfacial area, capillary pressure and saturation relationships in granular porous media

    Science.gov (United States)

    Joekar-Niasar, V.; Prodanović, M.; Wildenschild, D.; Hassanizadeh, S. M.

    2010-06-01

    We have developed a new approach for generating pore throat cross sections of various shapes based on distributions of shape factors and radii of inscribed circles. These distributions are obtained from analysis of grains packing. General formulas for calculating geometrical properties and entry capillary pressure for given shape factor and inscribed circle radius are developed. These relationships are employed in a pore network, which has a number of special features. In particular, it is highly flexible in terms of location of pore bodies, variable coordination number, as well as variable cross-sectional shapes. The pore network model is employed for simulating the equilibrium distribution of two fluids in a granular porous medium, under both drainage and imbibition conditions. The pore network model is verified by comparing simulation results with experimental data of quasi-static drainage and imbibition experiments in a glass bead medium. The pore-level topology and geometrical description of pore bodies and pore throats, essential for building the network, are rigorously extracted from experimental data using image analysis (3DMA-Rock software). Calculated capillary pressure-saturation (Pc - Sw) and specific interfacial area-saturation (anw - Sw) curves show very good agreement with measured ones, for both drainage and imbibition. We show that the shape factor can significantly influence the form of macroscopic Pc - Sw and anw - Sw curves, if the length and volumes associated to the pore throats are considerable. Furthermore, using continuous generation of shape factor distribution, the model can be validated against the grain size distribution. After validating the model against experiments, in addition to primary and main curves, we simulate many scanning curves to generate Pc - Sw - anw surfaces for drainage and imbibition, separately. Results show that these two surfaces lie very close to each other, and the average normalized difference is small, in the

  1. Daily changes in oxygen saturation and pulse rate associated with particulate air pollution and barometric pressure.

    Science.gov (United States)

    Dockery, D W; Pope, C A; Kanner, R E; Martin Villegas, G; Schwartz, J

    1999-01-01

    Epidemiologic studies have linked fine particulate air pollution with increases in morbidity and mortality rates from cardiopulmonary complications. Although the underlying biologic mechanisms responsible for this increase remain largely unknown, potential pathways include transient declines in blood oxygenation and changes in pulse rate following exposures to particulate air pollution episodes. This study evaluated potential associations between daily measures of respirable particulate matter (PM) with pulse rate and oxygen saturation of the blood. Pulse rate and oxygen saturation (Spo2) using pulse oximetry were measured daily in 90 elderly subjects living near air pollution monitors during the winter of 1995-96 in Utah Valley. We also evaluated potential associations of oxygen saturation and pulse rate with barometric pressure. Small but statistically significant positive associations between day-to-day changes in Spo2 and barometric pressure were observed. Pulse rate was inversely associated with barometric pressure. Exposure to particulate pollution was not significantly associated with Spo2 except in male participants 80 years of age or older. Increased daily pulse rate, as well as the odds of having a pulse rate 5 or 10 beats per minute (bpm) above normal (normal is defined as the individual's mean pulse rate throughout the study period), were significantly associated with exposure to particulate pollution on the previous 1 to 5 days. The medical or biologic relevance of these increases in pulse rate following exposure to particulate air pollution requires further study.

  2. Measuring lateral saturated soil hydraulic conductivity at different spatial scales

    Science.gov (United States)

    Di Prima, Simone; Marrosu, Roberto; Pirastru, Mario; Niedda, Marcello

    2017-04-01

    substratum of Permian sandstone that exhibits very low drainage, thus preventing deep water percolation (Castellini et al., 2016). In the laboratory, small-scale lateral and vertical saturated hydraulic conductivity, Ks,v, were determined by the constant-head permeameter method (Klute and Dirksen, 1986) on 20 soil cubes of 1331 cm3 of volume (Bagarello and Sgroi, 2008), allowing determination of mean Ks anisotropy for the hillslope. In the field, small-scale Ks,v was determined by infiltration runs of the BEST (Lassabatere et al., 2006) type carried out using a ring with an inner diameter of 0.15 m. The BEST-steady algorithm, proposed by Bagarello et al. (2014), was used to analyze the cumulative infiltration curves in order to decrease the failure rate of the BEST algorithms (Di Prima et al., 2016). The in situ Ks,l at an intermediate spatial scale was estimated by a trench test (Blanco-Canqui et al., 2002) carried out on a monolith 50 cm wide, 68 cm long and 34.5 cm deep (the depth to substratum). Finally, the large spatial scale (hillslope-scale) Ks,lvalue was estimated from the outflow of a 8.5 m large drain and from the perched water table levels monitored in the hillslope, following the methodology of Brooks et al. (2004). Anisotropy was not detected, since the soil cube experiments did not revealed significant differences between Ks,v and Ks,l values. The differences between the Ks datasets measured by the cube and the BEST methods were not statistically significant at p = 0.05. These methods yielded Ks values 6.4 and 5.8 times lower than the hillslope-scale Ks,l, respectively. The Ks,l value obtained by the trench experiment in the soil monolith was 1440 mm h-1, which was only 1.5 times higher than the hillslope-scale Ks,l. Probably, the chosen size of soil monolith was sufficient to properly represent the spatial heterogeneity of the soil in the hillslope. This finding need to be confirmed by further trench tests in soil monoliths to be carried out in the studied

  3. The influence of surfactant sorption on capillary pressure-saturation relationships

    Energy Technology Data Exchange (ETDEWEB)

    Desai, F.N.; Demond, A.H.; Hayes, K.F.

    1991-12-31

    The capillary pressure-saturation relationship, a fundamental relationship in the description of multiphase flow, depends on the interfacial properties of the system. Sorption of a cationic surfactant such as cetyltrimethylammonium bromide (CTAB) at the various interfaces of a system changes interfacial properties such as electrophoretic mobility, interfacial tensions, and contact angle. The objective of this paper is to examine the effect of the changes in these interfacial properties on the capillary pressure-saturation relationships for the air-water-silica system. The results presented here show that as the sorption of CTAB increases, the naturally negatively-charged silica surface becomes positively charged. This change in charge is reflected in the contact angle which passes through a maximum when the electrophoretic mobility is close to zero. The spontaneous imbibition capillary pressure relationship is more sensitive to changes in interfacial properties than the drainage relationship. In the air-water-silica system studied here, no imbibition is observed at the maximum contact angle. The surface tension and contact angle can be used to predict both the drainage and imbibition relationships of the air-water-silica-CTAB systems from that of the air-water-silica system. The prediction is accomplished through scaling using the value of surface tension and the operational contact angle, which can be obtained from the intrinsic angle through the incorporation of corrections for roughness and interfacial curvature. A comparison of the measured and calculated capillary pressure relationships shows that it is possible to predict the effect of surfactant sorption on both drainage and imbibition capillary pressure-saturation relationships for the system studied.

  4. The influence of surfactant sorption on capillary pressure-saturation relationships

    Energy Technology Data Exchange (ETDEWEB)

    Desai, F.N.; Demond, A.H.; Hayes, K.F.

    1991-01-01

    The capillary pressure-saturation relationship, a fundamental relationship in the description of multiphase flow, depends on the interfacial properties of the system. Sorption of a cationic surfactant such as cetyltrimethylammonium bromide (CTAB) at the various interfaces of a system changes interfacial properties such as electrophoretic mobility, interfacial tensions, and contact angle. The objective of this paper is to examine the effect of the changes in these interfacial properties on the capillary pressure-saturation relationships for the air-water-silica system. The results presented here show that as the sorption of CTAB increases, the naturally negatively-charged silica surface becomes positively charged. This change in charge is reflected in the contact angle which passes through a maximum when the electrophoretic mobility is close to zero. The spontaneous imbibition capillary pressure relationship is more sensitive to changes in interfacial properties than the drainage relationship. In the air-water-silica system studied here, no imbibition is observed at the maximum contact angle. The surface tension and contact angle can be used to predict both the drainage and imbibition relationships of the air-water-silica-CTAB systems from that of the air-water-silica system. The prediction is accomplished through scaling using the value of surface tension and the operational contact angle, which can be obtained from the intrinsic angle through the incorporation of corrections for roughness and interfacial curvature. A comparison of the measured and calculated capillary pressure relationships shows that it is possible to predict the effect of surfactant sorption on both drainage and imbibition capillary pressure-saturation relationships for the system studied.

  5. Interarm difference in blood pressure

    DEFF Research Database (Denmark)

    Mehlsen, Jesper; Wiinberg, Niels

    2014-01-01

    The present study aimed at examining the interarm difference in blood pressure and its use as an indicator of peripheral arterial disease (PAD). Data were included from consecutive patients referred from their general practitioner to our vascular laboratory for possible PAD aged 50 years or older...... without known cardiac disease, renal disease, or diabetes mellitus. 824 patients (453 women) with mean age of 72 years (range: 50-101) were included. 491 patients had a diagnosis of hypertension and peripheral arterial disease (PAD) was present in 386 patients. Systolic blood pressure was 143 ± 24 mm......Hg and 142 ± 24 mmHg on the right and left arm, respectively (P = 0.015). The interarm difference was greater in patients with hypertension (P = 0.002) and PAD (P blood pressure was reproducible...

  6. Relating oxygen partial pressure, saturation and content: the haemoglobin–oxygen dissociation curve

    Directory of Open Access Journals (Sweden)

    Julie-Ann Collins

    2015-09-01

    The delivery of oxygen by arterial blood to the tissues of the body has a number of critical determinants including blood oxygen concentration (content, saturation (SO2 and partial pressure, haemoglobin concentration and cardiac output, including its distribution. The haemoglobin–oxygen dissociation curve, a graphical representation of the relationship between oxygen satur­ation and oxygen partial pressure helps us to understand some of the principles underpinning this process. Historically this curve was derived from very limited data based on blood samples from small numbers of healthy subjects which were manipulated in vitro and ultimately determined by equations such as those described by Severinghaus in 1979. In a study of 3524 clinical specimens, we found that this equation estimated the SO2 in blood from patients with normal pH and SO2 >70% with remarkable accuracy and, to our knowledge, this is the first large-scale validation of this equation using clinical samples. Oxygen saturation by pulse oximetry (SpO2 is nowadays the standard clinical method for assessing arterial oxygen saturation, providing a convenient, pain-free means of continuously assessing oxygenation, provided the interpreting clinician is aware of important limitations. The use of pulse oximetry reduces the need for arterial blood gas analysis (SaO2 as many patients who are not at risk of hypercapnic respiratory failure or metabolic acidosis and have acceptable SpO2 do not necessarily require blood gas analysis. While arterial sampling remains the gold-standard method of assessing ventilation and oxygenation, in those patients in whom blood gas analysis is indicated, arterialised capillary samples also have a valuable role in patient care. The clinical role of venous blood gases however remains less well defined.

  7. Control of hearing-aid saturated sound pressure level by frequency-shaped output compression limiting.

    Science.gov (United States)

    McDermott, H J; Dean, M R; Dillon, H

    1999-01-01

    To fit a hearing aid successfully, it is important to set the Saturated Sound Pressure Level (SSPL) or Maximum Power Output (MPO) appropriately. The SSPL should be low enough to prevent sounds from being amplified to uncomfortable loudness, and yet high enough to maximize speech intelligibility and signal quality. To help attain an optimum SSPL setting, a novel output compression limiting scheme, with shapable MPO (ShaMPO), has been devised. In ShaMPO, the SSPL is shaped across frequencies in accordance with the individual user's loudness discomfort levels (LDLs). The contributions of different frequency regions to loudness are controlled by summing the amplified signal power relative to the LDLs across frequencies, and using this signal to control a wideband compressor. This scheme and a conventional output compression limiting (AGCo) scheme have been implemented in a digital hearing aid. Ten subjects, with moderately-severe to profound sensorineural hearing losses, participated in a study comparing speech intelligibility and listening comfort for the two schemes. Results showed that there were no significant differences in the speech perception scores between AGCo and ShaMPO, even when the speech was presented at 80 dBA, at which level both schemes were in compression much of the time. However, an examination of how subjects selected the SSPL for the two schemes revealed that, in many instances, AGCo would permit some sounds with compact spectra to be amplified above LDL, whereas ShaMPO would not. Thus the ShaMPO scheme can improve listening comfort for some intense sounds without a loss of speech intelligibility. In contrast, half the subjects found speech at 80 dBA to be uncomfortably loud when listening through their own aids.

  8. Distinct saturable pathways for the endocytosis of different tyrosine motifs.

    Science.gov (United States)

    Warren, R A; Green, F A; Stenberg, P E; Enns, C A

    1998-07-03

    Endocytosis of surface proteins through clathrin-coated pits requires an internalization signal in the cytoplasmic domain. Two types of internalization signal have been described: one requiring a tyrosine as the critical residue (tyrosine-based motif), and the other consisting of either two consecutive leucines or an isoleucine and leucine (dileucine motif). Although it seems that these signals are necessary and sufficient for endocytic targeting, the mechanism of recognition is not well understood. To examine this question, tetracycline-repressible cell lines were used to overexpress one of several receptors bearing a tyrosine-based internalization signal. By measuring the rates of endocytosis for either the overexpressed receptor, or that of other endogenous receptors, we were able to show that the endocytosis of identical receptors could be saturated, but a complete lack of competition exists between the transferrin receptor (TfR), the low-density lipoprotein receptor, and the epidermal growth factor receptor. Overexpression of any one of these receptors resulted in its redistribution toward the cell surface, implying that entry into coated pits is limited. During high levels of TfR expression, however, a significant increase in the amount of surface Lamp1, but not low-density lipoprotein receptor, epidermal growth factor receptor, or Lamp2, is detected. This suggests that Lamp1 and TfR compete for the same endocytic sites. Together, these results support the idea that there are at least three distinct saturable components involved in clathrin-mediated endocytosis.

  9. Pore pressure diffusion and the hydrologic response of nearly saturated, thin landslide deposits of rainfall

    Energy Technology Data Exchange (ETDEWEB)

    Haneberg, W.C. (New Mexico Bureau of Mines and Mineral Resources, New Mexico Institute of Mining and Technology, Socorro, NM (United States))

    1991-11-01

    Previous workers have correlated slope failures during rainstorms with rainfall intensity, rainfall duration, and seasonal antecedent rainfall. This note shows how such relationships can be interpreted using a periodic steady-state solution to the well-known linear pressure diffusion equation. Normalization of the governing equation yields a characteristic response time that is a function of soil thickness, saturated hydraulic conductivity, and pre-storm effective porosity, and which is analogous to the travel time of a piston wetting front. The effects of storm frequency and magnitude are also successfully quantified using dimensionless attenuation factors and lag times.

  10. Numerical study of two-phase flows in porous media : extraction of a capillary pressure saturation curve free from boundary effects

    Science.gov (United States)

    Fiorentino, Eve-Agnès; Moura, Marcel; Jørgen Måløy, Knut; Toussaint, Renaud; Schäfer, Gerhard

    2015-04-01

    The capillary pressure saturation relationship is a key element in the resolution of hydrological problems that involve the closure partial-flow Darcy relations. This relationship is derived empirically, and the two typical curve fitting equations that are used to describe it are the Brooks-Corey and Van Genüchten models. The question we tackle is the influence of the boundary conditions of the experimental set-up on the measurement of this retention curve, resulting in a non physical pressure-saturation curve in porous media, due the "end effects" phenomenon. In this study we analyze the drainage of a two-phase flow from a quasi 2D random porous medium, and compare it to simulations arising from an invasion percolation algorithm. The medium is initially saturated with a viscous fluid, and as the pressure difference is gradually increased, air penetrates from an open inlet, thus displacing the fluid which leaves the system from the outlet in the opposing side. In the initial stage, the liquid-air interface evolves from a planar front to the fractal structure characteristic of slow drainage processes, giving the initial downward curvature. In the final stage, air spreads all along the filter, and must reach narrower pores, calling for an increase of the pressure difference, reflected by the final upward curvature. Measuring the pressure-saturation (P-S) law in subwindows located at the inlet, outlet and middle of the network, we emphasize that these boundary effects are the fact of a fraction of pores that is likely to be negligible for high scale systems. We analyze the value of the air saturation at the end of the experiment for a series of simulations with different sample geometries : we observe that this saturation converges to a plateau when the distance between the inlet ant outlet increases, and that the value of this plateau is determined by the distance between the lateral walls. We finally show that the pressure difference between the two phases

  11. Dynamic testing of concrete under high confined pressure. Influence of saturation ratio and aggregate size

    Directory of Open Access Journals (Sweden)

    Forquin P.

    2015-01-01

    Full Text Available Concrete structures can be exposed to intense pressure loadings such as projectile-impact or detonation near a concrete structural element. To investigate the mechanical behaviour of concrete under high confining pressure, dynamic quasi-oedometric compression tests have been performed with a large diameter (80 mm Split Hopkinson Pressure Bar apparatus. The concrete sample is placed within a steel confining ring and compressed along its axial direction. Hydrostatic pressures as high as 800 MPa and axial strain of about − 10% are reached during the tests. In the present work, experiments have been conducted on two types of concrete: MB50 microconcrete with a maximum grain size of 2 mm and R30A7 ordinary concrete of maximum grain size about 8 mm. Both concretes are tested in dry or saturated conditions. According to these dynamic experiments it is noted that grain size has a small influence whereas water content has a strong effect on the confined behaviour of concrete.

  12. Growth of the microalgae Neochloris oleoabundans at high partial oxygen pressures and sub-saturating light intensity

    NARCIS (Netherlands)

    Sousa, C.A.; Winter, de L.; Janssen, M.G.J.; Vermue, M.H.; Wijffels, R.H.

    2012-01-01

    The effect of partial oxygen pressure on growth of Neochloris oleoabundans was studied at sub-saturating light intensity in a fully-controlled stirred tank photobioreactor. At the three partial oxygen pressures tested (PO2=0.24; 0.63; 0.84 bar), the specific growth rate was 1.38; 1.36 and 1.06

  13. Effects of different pulmonary vasodilators on arterial saturation in a model of pulmonary hypertension.

    Directory of Open Access Journals (Sweden)

    Eva Maria Becker

    Full Text Available BACKGROUND: Approved therapies for pulmonary arterial hypertension can induce oxygen desaturation when administered to patients with secondary forms of pulmonary hypertension (PH, probably due to an increase in ventilation/perfusion mismatch. Thus, so far these treatments have largely failed in secondary forms of PH. METHODS: We established an animal model of heterogeneous lung ventilation to evaluate the desaturation potential of mechanistically distinct vasoactive drugs launched or currently in clinical development for the treatment of PH. Single-lung ventilation was induced in five groups (N = 6 of anesthetized minipigs (7 weeks, 4 to 5 kg BW, and their hemodynamic parameters were monitored before and after intravenous injection of control (vehicle only, endothelin antagonist (bosentan; 0.3, 1, 3, 10 mg/kg, phosphodiesterase type 5 inhibitor (sildenafil; 3, 10, 30, 100 µg/kg, and soluble guanylate cyclase stimulators (BAY 41-8543 and riociguat; 1, 3, 10, 30 µg/kg. Cumulative doses were administered before successive unilateral ventilation cycles. The doses were chosen to achieve equal effect on blood pressure by the different pharmacologic principles. RESULTS: Single-lung ventilation resulted in transient increases in mean pulmonary artery pressure (mPAP and desaturation. In contrast to control, all drugs dose-dependently decreased hypoxic mPAP (a positive treatment effect and increased area under the arterial hemoglobin saturation curve (unwanted desaturation effect. Riociguat and bosentan reduced hypoxic mPAP to the greatest extent, while the soluble guanylate cyclase stimulators riociguat and BAY 41-8543 lowered arterial oxygen saturation of hemoglobin the least. CONCLUSIONS: Future investigations will be required to confirm these findings in clinical settings.

  14. Non-invasive positive pressure ventilation during sleep at 3800 m: Relationship to acute mountain sickness and sleeping oxyhaemoglobin saturation.

    Science.gov (United States)

    Johnson, Pamela L; Popa, Daniel A; Prisk, G Kim; Edwards, Natalie; Sullivan, Colin E

    2010-02-01

    Overnight oxyhaemoglobin desaturation is related to AMS. AMS can be debilitating and may require descent. Positive pressure ventilation during sleep at high altitude may prevent AMS and therefore be useful in people travelling to high altitude, who are known to suffer from AMS. Ascent to high altitude results in hypobaric hypoxia and some individuals will develop acute mountain sickness (AMS), which has been shown to be associated with low oxyhaemoglobin saturation during sleep. Previous research has shown that positive end-expiratory pressure by use of expiratory valves in a face mask while awake results in a reduction in AMS symptoms and higher oxyhaemoglobin saturation. We aimed to determine whether positive pressure ventilation would prevent AMS by increasing oxygenation during sleep. We compared sleeping oxyhaemoglobin saturation and the incidence and severity of AMS in seven subjects sleeping for two consecutive nights at 3800 m above sea level using either non-invasive positive pressure ventilation that delivered positive inspiratory and expiratory airway pressure via a face mask, or sleeping without assisted ventilation. The presence and severity of AMS were assessed by administration of the Lake Louise questionnaire. We found significant increases in the mean and minimum sleeping oxyhaemoglobin saturation and decreases in AMS symptoms in subjects who used positive pressure ventilation during sleep. Mean and minimum sleeping SaO2 was lower in subjects who developed AMS after the night spent without positive pressure ventilation. The use of positive pressure ventilation during sleep at 3800 m significantly increased the sleeping oxygen saturation; we suggest that the marked reduction in symptoms of AMS is due to this higher sleeping SaO2. We agree with the findings from previous studies that the development of AMS is associated with a lower sleeping oxygen saturation.

  15. Determination of Minimum Miscibility Pressure in supercritical extractor using oil saturated sample

    DEFF Research Database (Denmark)

    Rudyk, Svetlana Nikolayevna; Søgaard, Erik Gydesen; Abbasi, Waqas A.

    2009-01-01

      The main parameter for determination of the possibilities to enhance oil recovery by e.g. CO2 injection into a specific oil field is the measurement of Minimum Miscibility Pressure (MMP). This pressure is the lowest pressure for which a gas can obtain miscibility through a multi contact process...... with a given oil reservoir at the reservoir temperature. The oil formation to which the process is applied must be operated at or above the MMP. Before field trial this parameter is to be determined at the laboratory which traditionally is done by help of a slim tube or a raising bubble experiments. However...... vessel containing the sample at different increasing pressure levels. The oil displaced in such a way was collected and measured. The volume of extracted oil was plotted against the increasing pressure. The form of the graph is similar to that typically obtained from a slim tube experiment.  Following...

  16. Experiments on two-phase flow in a quasi-2D porous medium: investigation of boundary effects in the measurement of pressure-saturation relationships

    Science.gov (United States)

    Moura, Marcel; Fiorentino, Eve-Agnès; Jørgen Måløy, Knut; Toussaint, Renaud; Schäfer, Gerhard

    2015-04-01

    We have performed two-phase flow experiments to analyze the drainage from a quasi-2D random porous medium. The medium is transparent, which allows for the visualization of the invasion pattern during the flow and is initially fully saturated with a viscous fluid (a dyed glycerol-water mix). As the pressure in the fluid is gradually reduced, air penetrates from an open inlet, thus displacing the fluid which leaves the system from the outlet in the opposite side. A feedback mechanism was devised to control the experiment: the capillary pressure (difference in pressure between the non-wetting and wetting phases) is continuously increased to be just above the threshold value necessary to drive the invasion process. This mechanism is intended to keep the invasion process slow, in the so-called capillary regime, where capillary forces dominate the dynamics. Pressure measurements and pictures of the flow are recorded and the pressure-saturation relationship is computed. The effects of the boundary conditions to this quantity are verified experimentally by repeatedly performing the analysis using porous media of different sizes. We show that some features of the pressure-saturation curve are strongly affected by boundary effects. The invasion close to the inlet and outlet of the model are particularly influenced by the boundaries and this is reflected in the phases of pressure building up in the pressure-saturation curves, in the beginning and end of the invasion process. Conversely, at the central part of the model (away from the boundaries), the invasion process happens at an essentially constant capillary pressure, which is reflected as a plateau in the pressure-saturation curve. Additionally, the use of a high-resolution camera allows us to analyze the images down to the pore scale. We can directly obtain a distribution of pore-throat sizes in the model (and their associated capillary pressure thresholds) and divide it into distributions of invaded / non-invaded pores

  17. Effects of variable blast pressures on blood flow and oxygen saturation in rat brain as evidenced using MRI.

    Science.gov (United States)

    Bir, Cynthia; Vandevord, Pamela; Shen, Yimin; Raza, Waqar; Haacke, E Mark

    2012-05-01

    It has been recognized that primary blast waves may result in neurotrauma in soldiers in theater. A new type of contrast used in magnetic resonance imaging (MRI), susceptibility-weighted imaging (SWI), has been developed that is based on the different susceptibility levels in diverse tissues and can detect decreases in cerebral blood flow (CBF) using inferred oxygen saturation changes in tissue. In addition, a continuous arterial spin-labeled (ASL) MRI sequence was used as a direct measure of regional CBF within the brain tissue. Animals were subjected to whole-body blast exposures of various overpressures within a gas-driven shock tube. When exposed to low levels of overpressure, most rats demonstrated no obvious changes between pre- and postexposure in the conventional MR images. CBF changes measured by SWI and ASL were significantly higher for the overpressure exposed groups as compared to the sham group and tended to increase with pressure increases at the highest two pressures. In the hippocampus, all blast animals had a reduction in the CBF consistently in the range of 0-27%. In summary, low levels of primary blast pressure exposure demonstrated a significant physiologic effect to the brain up to 72 h postexposure. Copyright © 2012 Elsevier Inc. All rights reserved.

  18. Oxygen Saturation in the Dental Pulp of Maxillary Premolars in Different Age Groups - Part 1.

    Science.gov (United States)

    Estrela, Carlos; Serpa, Giuliano C; Alencar, Ana Helena G; Bruno, Kely F; Barletta, Fernando B; Felippe, Wilson T; Estrela, Cyntia R A; Souza, João B

    2017-01-01

    The aim of this study was to determine oxygen saturation levels in the dental pulp of maxillary premolars in different age groups. A total of 120 human maxillary premolars with normal dental pulps were selected covering the following age groups: 20-24, 25-29, 30-34, 35-39 and 40-44 years (n=24 each group). Oxygen saturation was assessed using pulse oximetry. Analysis of variance was used to assess differences in oxygen saturation levels and Tukey's test was used to identify the age groups that differed from each other. Significance was set at 0.05. Mean oxygen saturation of 120 premolars was 86.20% considering all age groups. Significantly reduced levels were found in the oldest group compared to the other groups: 40 to 44 years - 80.00% vs. 89.71, 87.67, 88.71, and 84.80% for age groups 20-24, 25-29, 30-34, 35-39 years, respectively. The mean oxygen saturation levels were similar between 20 and 39 years of age (86.20%) in the whole sample, but reduced significantly in the 40-44-year age group, suggesting that older patients present lower oxygen saturation results even in the absence of pulp tissue injury.

  19. Sildenafil Increases Systemic Saturation and Reduces Pulmonary Artery Pressure in Patients with Failing Fontan Physiology.

    Science.gov (United States)

    Morchi, Gira S; Ivy, D Dunbar; Duster, Mark C; Claussen, Lori; Chan, Kak-Chen; Kay, Joseph

    2009-04-01

    OBJECTIVE: The purpose of this study was to investigate the effect of sildenafil in patients with failing Fontan physiology. DESIGN: A retrospective chart review was performed to compare history and available data in patients with Fontan circulations before and after starting sildenafil. The paired and unpaired Student's t-tests were used for statistical analyses. PATIENTS: Six patients at our institution with Fontan physiology, persistent symptoms of cyanosis or effusion, and poor hemodynamics as measured in the catheterization laboratory were placed on sildenafil. One patient was not included in the analysis because of insufficient length of treatment. All patients had symptoms of failing Fontan hemodynamics with either persistent cyanosis or effusions. In this group, the mean pulmonary artery pressure was greater than 15 mm Hg (17.4 ± 1.5 mm Hg) with mean estimated pulmonary vascular resistance of 3.5 ± 1.0 Wood units × m(2) prior to starting sildenafil. RESULTS: Sildenafil significantly increased the systemic arterial oxyhemoglobin saturation in this group (82.8 ± 7.3% pre-treatment vs. 91.0 ± 5.5% post-treatment, P = .017). In the four out of five patients who have had follow-up catheterizations, there was a significant decrease in pulmonary artery pressure (17.4 ± 1.5 mm Hg pre-treatment vs. 13.8 ± 2.1 mm Hg post-treatment, P = .018) and in estimated pulmonary vascular resistance pre- and post-sildenafil treatment (3.5 ± 1.0 Wood units × m(2) pre-treatment vs. 2.0 ± 0.4 Wood units × m(2) post-treatment, P = .031). CONCLUSIONS: Sildenafil may be a useful adjunct to therapy in patients with failing Fontan physiology likely through its function as a pulmonary vasodilator.

  20. Determination of saturation pressure and enthalpy of vaporization of semi-volatile aerosols: the integrated volume mentod

    Science.gov (United States)

    This study presents the integrated volume method for estimating saturation pressure and enthalpy of vaporization of a whole aerosol distribution. We measure the change of total volume of an aerosol distribution between a reference state and several heated states, with the heating...

  1. Salinity of injection water and its impact on oil recovery absolute permeability, residual oil saturation, interfacial tension and capillary pressure

    Directory of Open Access Journals (Sweden)

    Mehdi Mohammad Salehi

    2017-06-01

    This paper presents laboratory investigation of the effect of salinity injection water on oil recovery, pressure drop, permeability, IFT and relative permeability in water flooding process. The experiments were conducted at the 80 °C and a net overburden pressure of 1700 psi using core sample. The results of this study have been shown oil recovery increases as the injected water salinity up to 200,000 ppm and appointment optimum salinity. This increase has been found to be supported by a decrease in the IFT. This effect caused a reduction in capillary pressure increasing the tendency to reduce the residual oil saturation.

  2. Effect of CH4 on the CO2 breakthrough pressure and permeability of partially saturated low-permeability sandstone in the Ordos Basin, China

    Science.gov (United States)

    Zhao, Yan; Yu, Qingchun

    2018-01-01

    The behavior of CO2 that coexists with CH4 and the effect of CH4 on the CO2 stream need to be deeply analyzed and studied, especially in the presence of water. Our previous studies investigated the breakthrough pressure and permeability of pure CO2 in five partially saturated low-permeability sandstone core samples from the Ordos Basin, and we concluded that rocks with a small pore size and low permeability show considerable sealing capacity even under unsaturated conditions. In this paper, we selected three of these samples for CO2-CH4 gas-mixture breakthrough experiments under various degrees of water saturation. The breakthrough experiments were performed by increasing the gas pressure step by step until breakthrough occurred. Then, the effluent gas mixture was collected for chromatographic partitioning analysis. The results indicate that CH4 significantly affects the breakthrough pressure and permeability of CO2. The presence of CH4 in the gas mixture increases the interfacial tension and, thus, the breakthrough pressure. Therefore, the injected gas mixture that contains the highest (lowest) mole fraction of CH4 results in the largest (smallest) breakthrough pressure. The permeability of the gas mixture is greater than that for pure CO2 because of CH4, and the effective permeability decreases with increased breakthrough pressure. Chromatographic partitioning of the effluent mixture gases indicates that CH4 breaks through ahead of CO2 as a result of its weaker solubility in water. Correlations are established between (1) the breakthrough pressure and water saturation, (2) the effective permeability and water saturation, (3) the breakthrough pressure and effective permeability, and (4) the mole fraction of CO2/CH4 in the effluent mixture gases and water saturation. These results deepen our understanding of the multi-phase flow behavior in the porous media under unsaturated conditions, which have implications for formulating emergency response plans for gas

  3. Border control! Capillary pressure / saturation relationships in a diphasic flow in a random medium: Influence of the boundary conditions

    Science.gov (United States)

    Fiorentino, Eve-Agnès; Toussaint, Renaud; Moura, Marcel; Jankov, Mihailo; Schäfer, Gerhard; Jørgen Måløy, Knut

    2013-04-01

    Solving problems involving biphasic flows in porous media, at a scale larger than the pore one, normally requires the use of relationships between pressure and saturation. These allow the closure of generalized Darcy flow models for two phases, commonly used in hydrology or large scale problems of diphasic flow in porous media. There are mathematical models which approximate experimental records with curve-fitting equations. The two most common models are the Brooks-Corey and van Genüchten ones, they are used to complete a system of generalized Darcy equations. The purpose of the current study is the influence of the boundary conditions on the relationship between pressure and saturation. We perform numerical simulations of drainage experiments. Water is the wetting fluid and air is the non wetting fluid. The results highlight the fact that a filter which allows only water to flow at the exit face of the system modifies both the shape of the curve and the value of the residual saturation. The pressure of the models that are commonly used does not match with the pressure of real flows since there is no filter to cross, to flow from an elementary volume to another. Experiments performed in transparent Hele-Shaw cells exhibit the same features, showing the influence of the semi permeable boundary conditions on the pressure-saturation measures obtained. This effect corresponding to the formation of localized plugging clusters at the boundaries, is obtained in slow flow conditions, and is independent of any dynamic fingering, also known to affect such relations (1,2,3). Modeling flows in open media thus would require to use the central part of the curves pressure saturation where the effect of the boundaries is the least important, or to modify properly these relationships to extract the behavior unaffected by boundaries. References: (1) Two-phase flow: structure, upscaling, and consequences for macroscopic transport properties Renaud Toussaint ; Knut Jørgen M

  4. Impact of the capillary pressure-saturation pore-size distribution parameter on geological carbon sequestration estimates

    Directory of Open Access Journals (Sweden)

    Chu-Lin Cheng

    2017-01-01

    Full Text Available Cost estimates for geologic carbon sequestration (GCS are vital for policy and decision makers evaluating carbon capture and storage strategies. Numerical models are often used in feasibility studies for the different stages of carbon injection and redistribution. Knowledge of the capillary pressure-saturation function for a selected storage rock unit is essential in applications used for simulating multiphase fluid flow and transport. However, the parameters describing these functions (e.g. the van Genuchten m pore size distribution parameter are often not measured or neglected compared to other physical properties such as porosity and intrinsic permeability. In addition, the use of average instead of point estimates of m for numerical simulations of flow and transport can result in significant errors, especially in the case of coarse-grained sediments and fractured rocks. Such erroneous predictions can pose great risks and challenges to decision-making. We present a comparison of numerical simulation results based on average and point estimates of the van Genuchten m parameter for different porous media. Forward numerical simulations using the STOMP code were employed to illustrate the magnitudes of the differences in carbon sequestration predictions resulting from the use of height-averaged instead of point parameters. The model predictions were converted into cost estimates and the results indicate that varying m values in GCS modeling can cause cost differences of up to hundreds of millions dollars.

  5. Remote Sensing to Estimate Saturation Differences of Chosen Building Materials Using Terrestrial Laser Scanner

    Science.gov (United States)

    Suchocki, Czesław; Katzer, Jacek; Panuś, Arkadiusz

    2017-06-01

    Terrestrial Laser Scanner (TLS) method which is commonly used for geodetic applications has a great potential to be successfully harnessed for multiple civil engineering applications. One of the most promising uses of TLS in construction industry is remote sensing of saturation of building materials. A research programme was prepared in order to prove that harnessing TLS for such an application is viable. Results presented in the current paper are a part of a much larger research programme focused on harnessing TLS for remote sensing of saturation of building materials. The paper describes results of the tests conducted with an impulse scanner Leica C-10. Tests took place both indoors (in a stable lab conditions) and outdoors (in a real environment). There were scanned specimens of the most popular building materials in Europe. Tested specimens were dried and saturated (including capillary rising moisture). One of the tests was performed over a period of 95 hours. Basically, a concrete specimen was scanned during its setting and hardening. It was proven that absorption of a laser signal is influenced by setting and hardening of concrete. Outdoor tests were based on scanning real buildings with partially saturated facades. The saturation assessment was based on differences of values of intensity. The concept proved to be feasible and technically realistic.

  6. Procyanidins in Lotus L. genotypes grown in soil with different saturations of aluminum

    Directory of Open Access Journals (Sweden)

    Sílvia Ortiz Chini

    2016-02-01

    Full Text Available Condensed tannins are formed by monomers of procyanidins and prodelfinidins, where the proportion and concentration of their monomers varies according to the plant species and environmental conditions. In Lotus spp., condensed tannins prevent tympanism in ruminants that feed on them. This study aimed to evaluate the concentration of procyanidins and their monomers, catechin and epicatechin in the genotypes of Lotus L. grown in soil with different saturations of aluminum. A two-factor (genotype × Al saturation assay was performed, where the genotypes São Gabriel, Ganador, and UFRGS (Lotus corniculatus L.; Serrano (Lotus uliginosus; and El Rincón (Lotus subbiflorus were cultivated in soil with an Al saturation of 0-20%. The procyanidins were evaluated using high-performance liquid chromatography, which was previously validated for catechin and epicatechin. The concentration of procyanidins and the proportion of epicatechin:catechin were affected by the genotype × environment interaction. In L. corniculatus and L. subbiflorus, the concentration of procyanidin was significantly higher when they were grown in the soil with an Al saturation of 20% compared to that when they were grown in the soil with 0% Al saturation, but the opposite effect was observed in L. uliginosus. The proportion of epicatechin:catechin decreased in plants grown in soil without Al, and only the UFRGS genotype maintained a similar proportion under both the soil acidity conditions. The predominant monomer was epicatechin, which varied from 57% to 75% according to the soil in which the plants were grown.

  7. Salinity of injection water and its impact on oil recovery absolute permeability, residual oil saturation, interfacial tension and capillary pressure

    OpenAIRE

    Mohammad Salehi, Mehdi; Omidvar, Pouria; Naeimi, Fatemeh

    2016-01-01

    Laboratory tests and field applications show that low-salinity water flooding could lead to significant reduction of residual oil saturation. There has been a growing interest with an increasing number of low-salinity water flooding studies. However, there are few quantitative studies on flow and transport behavior of low-salinity IOR processes. This paper presents laboratory investigation of the effect of salinity injection water on oil recovery, pressure drop, permeability, IFT and relat...

  8. A graphic-analytical method for determining saturation pressure in oil deposits

    Energy Technology Data Exchange (ETDEWEB)

    Ramazanova, E.E.; Federtsov, V.K.; Ismaylov, K.K.

    1980-01-01

    This article summarizes factual material concerning a large number of oil deposits in the Soviet Union, and selections are made of statistical-probability models for these deposits. A graphic-analytical method is developed for determining involved in a gas saturation of oil.

  9. Phase equilibria and physical properties of CO2-saturated cocoa butter mixtures at elevated pressures

    NARCIS (Netherlands)

    Venter, M.J.; Willems, P.; Kareth, S.; Weidner, E.; Kuipers, N.J.M.; de Haan, A.B.

    2007-01-01

    The melting point and phase behaviour of cocoa butter under CO2 pressure were observed in a high-pressure view cell. The melting point decreases from 35 to 23 °C at CO2 pressures higher than 5 MPa. A static analytical procedure was used to measure the solubility of CO2 in cocoa butter at 40, 80 and

  10. Sensitivity analysis of effective fluid and rock bulk modulus due to changes in pore pressure, temperature and saturation

    Science.gov (United States)

    Bhakta, Tuhin; Avseth, Per; Landrø, Martin

    2016-12-01

    Fluid substitution plays a vital role in time-lapse seismic modeling and interpretation. It is, therefore, very important to quantify as exactly as possible the changes in fluid bulk modulus due to changes in reservoir parameters. In this paper, we analyze the sensitivities in effective fluid bulk modulus due to changes in reservoir parameters like saturation, pore-pressure and temperature. The sensitivities are analyzed for two extreme bounds, i.e. the Voigt average and the Reuss average, for various fluid combinations (i.e. oil-water, gas-water and gas-oil). We quantify that the effects of pore-pressure and saturation changes are highest in the case of gas-water combination, while the effect of temperature is highest for oil-gas combination. Our results show that sensitivities vary with the bounds, even for same amount of changes in any reservoir parameter. In 4D rock physics studies, we often neglect the effects of pore-pressure or temperature changes assuming that those effects are negligible compare to the effect due to saturation change. Our analysis shows that pore-pressure and temperature changes can be vital and sometimes higher than the effect of saturation change. We investigate these effects on saturated rock bulk modulus. We first compute frame bulk modulus using the Modified Hashin Shtrikman (MHS) model for carbonate rocks and then perform fluid substitution using the Gassmann equation. We consider upper bound of the MHS as elastic behavior for stiffer rocks and lower bound of the MHS as elastic behavior for softer rocks. We then investigate four various combinations: stiff rock with upper bound (the Voigt bound) as effective fluid modulus, stiff rock with lower bound (Reuss bound) as effective fluid modulus, soft rock with upper bound as effective fluid modulus and soft rock with lower bound as effective fluid modulus. Our results show that the effect of any reservoir parameter change is highest for soft rock and lower bound combination and lowest

  11. Transdentinal cytotoxicity of experimental adhesive systems of different hydrophilicity applied to ethanol-saturated dentin.

    Science.gov (United States)

    Bianchi, Luciana; Ribeiro, Ana Paula Dias; de Oliveira Carrilho, Marcela Rocha; Pashley, David H; de Souza Costa, Carlos Alberto; Hebling, Josimeri

    2013-09-01

    The aim of this study was to evaluate the transdentinal cytotoxicity of experimental adhesive systems (EASs) with different hydrophilicity and dentin saturation solutions on odontoblast-like cells. One hundred 0.4-mm-thick dentin discs were mounted in in vitro pulp chambers and assigned to 10 groups. MDPC-23 cells were seeded onto the pulpal side of the discs, incubated for 48h. The EASs with increasing hydrophilicity (R1, R2, R3 and R4) were applied to the occlusal side after etching and saturation of etched dentin with water or ethanol. R0 (no adhesive) served as controls. R1 is a non-solvated hydrophobic blend, R2 is similar to a simplified etch-and-rinse adhesive system and R3 and R4 are similar to self-etching adhesives. After 24h, cell metabolism was evaluated by MTT assay (n=8 discs) and cell morphology was examined by SEM (n=2 discs). Type of cell death was identified by flow cytometry and the degree of monomer conversion (%DC) was determined by infrared spectroscopy (FTIR) after 10s or 20s of photoactivation. Data were analyzed by the Kruskal-Wallis and Mann-Whitney tests (α=0.05). Dentin saturation with ethanol resulted in higher necrotic cell death ratios for R2, R3 and R4 compared with water saturation, although R2 and R3 induced higher SDH production. Photoactivation for 20s significantly improved the %DC of all EASs compared with 10s. A significant positive correlation was observed between the degree of hydrophilicity and %DC. In conclusion, except for R1, dentin saturation with ethanol increased the cytotoxicity of EASs, as expressed by the induction of necrotic cell death. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  12. Correlation Between Pediatric Open Heart Surgery Outcomes and Arterial-mixed Venous Oxygen Saturation Differences

    Directory of Open Access Journals (Sweden)

    Mahmood Samadi

    2012-09-01

    Full Text Available Introduction: Low Cardiac Output Syndrome (LCOS contributes to postoperative morbidity and mortality. This article tries to find a predictive factor to interpret outcome after cardiac operation. Methods: In a cross-sectional study, 100 children with congenital heart disease undergoing cardiovascular surgery with cardiopulmonary bypass (CPB without significant left-to-right shunt were selected. Arterial and central venous oxygen saturation values were measured via blood samples simultaneously obtained in 6-hr intervals for a total of 24-hr during postoperative period at hours 0, 6, 12, 18, and 24. Postoperative ventilation support (intubation period and cardiovascular support were also obtained from the hospital records. Statistical analysis was later performed comparing the arterial-mixed venous oxygen saturation differences and durations of required ventilatory and cardiovascular support, both for the complicated and non-complicated patient groups. The data was processed with correlation Pearson and Mann-Whitney U tests in SPSS 15 software, P less than 0.05 was significant. Results: Mortality following cardiac operation is 6% and complications may happen in 45% of the cases. The highest Arterial-mixed venous oxygen saturation difference occurred immediately post operation (up to 57%. These measures were high up to 18 hours in complicated and non-complicated groups (36% vs. 31% ; P 0.05. Conclusion: Arterial-mixed venous oxygen saturation difference may be high as much as 57% or as low as 23%.These different measures, being higher up to 18 hours in complicated to non-complicated groups after 18 hours, can be related to tissue ischemia during surgery and cannot be discriminative.

  13. Cerebral hypoxic ischemia at different cerebral oxygen saturations in piglets: amplitude-integrated EEG study.

    Science.gov (United States)

    Zhang, Dandan; Ding, Haiyan; Hou, Xinlin; Liu, Yunfeng; Ye, Datian

    2008-01-01

    the objective of present paper was to study the amplitude-integrated EEG (aEEG) in hypoxic ischemic (HI) animal models and to test the reliability of aEEG method when used to monitor cerebral injuries. HI animal models were constructed and classified into mild, moderate and severe cerebral oxygen saturation groups according to regional oxygen saturation (rSO(2)) in brains. Then aEEG waveforms were obtained from raw EEG data using digital signal processing. aEEG reflected cerebral functions consistently and accurately at different cerebral rSO(2) levels. aEEG waveforms rarely changed in the group of mild HI; they dropped but recovered in moderate HI group; and aEEG maintained very low after HI in the cases when severe HI happened. aEEG method could monitor cerebral functions directly, accurately and consistently. It is a reliable tool to continuously evaluate cerebral injuries.

  14. Effect of Collagen Matrix Saturation on the Surface Free Energy of Dentin using Different Agents.

    Science.gov (United States)

    de Almeida, Leopoldina de Fátima Dantas; Souza, Samilly Evangelista; Sampaio, Aline Araújo; Cavalcanti, Yuri Wanderley; da Silva, Wander José; Del Bel Cur, Altair A; Hebling, Josimeri

    2015-07-01

    The surface free energy of conditioned-dentin is one of the factors that interfere with monomeric infiltration of the interfibrillar spaces. Saturation of the tooth matrix with different substances may modulate this energy and, consequently, the wettability of the dentin. To evaluate the influence of different substances used to saturate conditioned-dentin on surface free energy (SFE) of this substrate. Dentin blocks (4 × 7 × 1 mm, n = 6/ group), obtained from the roots of bovine incisors, were etched using phosphoric acid for 15 seconds, rinsed and gently dried. The surfaces were treated for 60 seconds with: ultra-purified water (H20-control); ethanol (EtOH), acetone (ACT), chlorhexidine (CHX), ethylenediaminetetraacetic acid (EDTA); or sodium hypochlorite (NaOCl). The tooth surfaces were once again dried with absorbent paper and prepared for SFE evaluation using three standards: water, formamide and bromonaphthalene. Analysis of variance (ANOVA) and Dunnet's tests (a = 0.05) were applied to the data. Ethylenediaminetetraacetic acid was the only substance that caused a change to the contact angle for the standards water and formamide, while only EtOH influenced the angles formed between formamide and the dentin surface. None of the substances exerted a significant effect for bromonaphtha-lene. In comparison to the control, only EDTA and NaOCl altered both polar components of the SFE. Total SFE was increased by saturation of the collagen matrix by EDTA and reduced when NaOCl was used. Saturation of the collagen matrix by EDTA and EtOH changed the surface free energy of the dentin. In addition, the use of NaOCl negatively interfered with the properties evaluated. The increase of surface free energy and wettability of the dentin surface would allow higher penetration of the the adhesive system, which would be of importance to the clinical success of resin-dentin union.

  15. Crater density differences: Exploring regional resurfacing, secondary crater populations, and crater saturation equilibrium on the moon

    Science.gov (United States)

    Povilaitis, R Z; Robinson, M S; van der Bogert, C H; Hiesinger, Harald; Meyer, H M; Ostrach, Lillian

    2017-01-01

    The global population of lunar craters >20 km in diameter was analyzed by Head et al., (2010) to correlate crater distribution with resurfacing events and multiple impactor populations. The work presented here extends the global crater distribution analysis to smaller craters (5–20 km diameters, n = 22,746). Smaller craters form at a higher rate than larger craters and thus add granularity to age estimates of larger units and can reveal smaller and younger areas of resurfacing. An areal density difference map generated by comparing the new dataset with that of Head et al., (2010) shows local deficiencies of 5–20 km diameter craters, which we interpret to be caused by a combination of resurfacing by the Orientale basin, infilling of intercrater plains within the nearside highlands, and partial mare flooding of the Australe region. Chains of 5–30 km diameter secondaries northwest of Orientale and possible 8–22 km diameter basin secondaries within the farside highlands are also distinguishable. Analysis of the new database indicates that craters 57–160 km in diameter across much of the lunar highlands are at or exceed relative crater densities of R = 0.3 or 10% geometric saturation, but nonetheless appear to fit the lunar production function. Combined with the observation that small craters on old surfaces can reach saturation equilibrium at 1% geometric saturation (Xiao and Werner, 2015), this suggests that saturation equilibrium is a size-dependent process, where large craters persist because of their resistance to destruction, degradation, and resurfacing.

  16. Monitoring peri-ictal changes in heart rate variability, oxygen saturation and blood pressure in epilepsy monitoring unit.

    Science.gov (United States)

    Jaychandran, R; Chaitanya, G; Satishchandra, P; Bharath, R D; Thennarasu, K; Sinha, S

    2016-09-01

    The peri-ictal autonomic disturbances have been studied as predictors of seizure outcome and as markers of seizure onset. We studied the changes in heart rate (HR), HRV, oxygen saturation and blood pressure (BP) in the peri-ictal period in patients with drug-resistant localization-related epilepsy. Ninety one subjects undergoing video-EEG monitoring, underwent continuous HR, SpO2, BP and Lead II ECG monitoring. The changes during the preictal, ictal and postictal periods were analyzed for 57 seizures in 42 patients with artifact-free recordings and correlated with VEEG ictal onset and MRI characteristics. Ictal tachycardia was noted in 15 (26.3%) seizures, of which, 60% had temporal lobe onset. HR increased by an average of 20.1% from pre-ictal to ictal phases (p=0.04). Ictal bradycardia was noted in one event with right temporal seizure onset. Heart rate variability (HRV) analysis of the preictal, ictal and postictal phases showed an increase in the sympathetic and decrease in parasympathetic activity during the ictus with relatively preserved total power. Ictal oxygen desaturation (84.1%±3.5%) was noticed in 10 (17.5%) seizures. Ictal hypertension was observed in 15 (26.3%); ictal hypotension was noted in 5 (8.7%) seizures. Both the systolic BP and diastolic BPs increased from the pre-ictal to ictal phase (p=0.01). Peri-ictal dysautonomia can present in variable patterns and can be measured and compared over different modalities such as BP, HR and HRV. Though degree of tachycardia and increase in BP were higher during extratemporal onset of seizures, a fall in variability was noted in seizures of temporal lobe origin. Oxygen desaturation is not an uncommon event during the peri-ictal period in localization related epilepsy. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Experimental investigation of wettability alteration on residual oil saturation using nonionic surfactants: Capillary pressure measurement

    Directory of Open Access Journals (Sweden)

    Masoud Amirpour

    2015-12-01

    Full Text Available Introducing the novel technique for enhancing oil recovery from available petroleum reservoirs is one of the important issues in future energy demands. Among of all operative factors, wettability may be the foremost parameter affecting residual oil saturation in all stage of oil recovery. Although wettability alteration is one of the methods which enhance oil recovery from the petroleum reservoir. Recently, the studies which focused on this subject were more than the past and many contributions have been made on this area. The main objective of the current study is experimentally investigation of the two nonionic surfactants effects on altering wettability of reservoir rocks. Purpose of this work is to change the wettability to preferentially the water-wet condition. Also reducing the residual oil saturation (Sor is the other purpose of this work. The wettability alteration of reservoir rock is measured by two main quantitative methods namely contact angle and the USBM methods. Results of this study showed that surfactant flooding is more effective in oil-wet rocks to change their wettability and consequently reducing Sor to a low value. Cedar (Zizyphus Spina Christi is low priced, absolutely natural, and abundantly accessible in the Middle East and Central Asia. Based on the results, this material can be used as a chemical surfactant in field for enhancing oil recovery.

  18. Influence of Pore-Fluid Pressure on Elastic Wave Velocity and Electrical Conductivity in Water-Saturated Rocks

    Science.gov (United States)

    Higuchi, A.; Watanabe, T.

    2013-12-01

    Pore-fluid pressure in seismogenic zones can play a key role in the occurrence of earthquakes (e.g., Sibson, 2009). Its evaluation via geophysical observations can lead to a good understanding of seismic activities. The evaluation requires a thorough understanding of the influence of the pore-fluid pressure on geophysical observables like seismic velocity and electrical conductivity. We have studied the influence of pore-fluid pressure on elastic wave velocity and electrical conductivity in water-saturated rocks. Fine grained (100-500μm) biotite granite (Aji, Kagawa pref., Japan) was used as rock samples. The density is 2.658-2.668 g/cm3, and the porosity 0.68-0.87%. The sample is composed of 52.8% plagioclase, 36.0% Quartz, 3.0% K-feldspar, 8.2% biotite. SEM images show that a lot of grain boundaries are open. Few intracrystalline cracks were observed. Following the method proposed by David and Zimmerman (2012), the distribution function of crack aspect ratio was evaluated from the pressure dependence of compressional and shear wave velocities in a dry sample. Cylindrical sample has dimensions of 25 mm in diameter and 30 mm in length, and saturated with 0.01 mol/l KCl aqueous solution. Compressional and shear wave velocities were measured with the pulse transmission technique (PZT transducers, f=2 MHz), and electrical conductivity the two-electrode method (Ag-AgCl electrodes, f=1 Hz-100 kHz). Simultaneous measurements of velocities and conductivity were made using a 200 MPa hydrostatic pressure vessel, in which confining and pore-fluid pressures can be separately controlled. The pore-fluid is electrically insulated from the metal work of the pressure vessel by using a newly designed plastic device (Watanabe and Higuchi, 2013). The confining pressure was progressively increased up to 25 MPa, while the pore-fluid pressure was kept at 0.1 MPa. It took five days or longer for the electrical conductivity to become stationary after increasing the confining pressure

  19. Transdentinal cytotoxicity of experimental adhesive systems of different hydrophilicity applied to ethanol-saturated dentin

    OpenAIRE

    Bianchi, Luciana; Ribeiro, Ana Paula Dias; de Oliveira Carrilho, Marcela Rocha; Pashley, David H; de Souza Costa, Carlos Alberto; Hebling, Josimeri

    2013-01-01

    The aim of this study was to evaluate the transdentinal cytotoxicity of experimental adhesive systems (EASs) with different hydrophilicity and dentin saturation solutions (ethanol and water) on odontoblast-like cells. One hundred 0.4-mm-thick dentin discs were mounted in in vitro pulp chambers and assigned to 10 groups. Odontoblast-like cells MDPC-23 were seeded onto the pulpal side of the discs, incubated for 48h. The EASs with increasing hydrophilicity (R2, R3, R4 and R5) were applied to th...

  20. The effects of different ventilator modes on cerebral tissue oxygen saturation in patients with bidirectional superior cavopulmonary connection

    Directory of Open Access Journals (Sweden)

    Ayda Türköz

    2014-01-01

    Full Text Available Aims and Objectives: We used near-infrared spectroscopy to document changes in cerebral tissue oxygen saturation (SctO 2 in response to ventilation mode alterations after bidirectional Glenn (BDG; superior cavopulmonary connection procedure. We also determined whether spontaneous ventilation have a beneficial effect on hemodynamic status, lactate and SctO 2 when compared with other ventilation modes. Materials and Methods: 20 consecutive patients undergoing BDG were included. We measured SctO 2 during three ventilator modes (intermittent positive-pressure ventilation [IPPV]; synchronized intermittent mandatory ventilation [SIMV]; and continuous positive airway pressure + pressure support ventilation [CPAP + PSV]. We, also, measured mean airway pressure (AWP, arterial blood gases, lactate and systolic arterial pressures (SAP. Results: There was no change in SctO 2 in IPPV and SIMV modes; the SctO 2 measured during CPAP + PSV and after extubation increased significantly (60.5 ± 11, 61 ± 10, 65 ± 10, 66 ± 11 respectively ( P < 0.05. The differences in the SAP measured during IPPV and SIMV modes was insignificant; the SAP increased significantly during CPAP + PSV mode and after extubation compared with IPPV and SIMV (109 ± 11, 110 ± 12, 95 ± 17, 99 ± 13 mmHg, respectively ( P < 0.05. Mean AWP did not change during IPPV and SIMV modes, mean AWP decreased significantly during CPAP + PSV mode (14 ± 4, 14 ± 3, 10 ± 1 mmHg, respectively ( P < 0.01. Conclusions: The SctO 2 was higher during CPAP + PSV ventilation and after extubation compared to IPPV and SIMV modes of ventilation. The mean AWP was lower during CPAP + PSV ventilation compared to IPPV and SIMV modes of ventilation.

  1. Atomic fluorescence emitted from a corona discharge in helium above and below saturated vapour pressure

    Science.gov (United States)

    Shiltagh, Nagham M.; Mendoza Luna, Luis G.; Watkins, Mark J.; Thornton, Stuart C.; von Haeften, Klaus

    2018-01-01

    A new apparatus was constructed to investigate the visible and near infrared fluorescence spectroscopy of electronically excited helium over a wide range of pressures and temperatures, covering both the gaseous and liquid phases. To achieve sufficient throughput, increased sensitivity was established by employing a micro-discharge cell and a high performance lens system that allows for a large collection solid angle. With this set-up, several thousand spectra were recorded. The atomic 3 s 1 S → 2 p 1 P and 3 s 3 S → 2 p 3 P atomic transitions showed line shifts, spectral broadening and intensity changes that were dependent in magnitude on pressure, temperature and thermodynamic phase. While in the gas phase the lines showed little dependency on the discharge cell temperature, the opposite was observed for the liquid phase, suggesting that a significant number of atoms were solvated. Triplet lines were up to a factor of 50 times stronger in intensity than the singlet lines, depending on pressure. When taking the particle density into account, this effect was stronger in the gas phase than in the liquid phase of helium. This was attributed to the recombination of He2 +, He3 + and He4 + with electrons, which is facilitated in the gas phase because of the significantly higher mobility.

  2. The Effect of Films on the Capillary Pressure - Saturation Hysteresis in a Smooth-walled Wedge Channel

    Science.gov (United States)

    Liu, Y.; Nolte, D.; Pyrak-Nolte, L. J.

    2010-12-01

    Thin fluid films are central to many multiphase flow applications; however, experimental investigation of films requires direct detection and measurement of films. Water film thicknesses can range from a few nanometers to several micrometers and may vary depending on local pore structures and material properties. In this study, laser confocal microscopy was employed to image volumetric fluid distribution and 3D interfaces during drainage and imbibition processes in a smooth-walled channel. Confocal microscopy provides an effective method to image directly 3D thin films and to measure film thickness, volume, and other parameters. The detection resolution is 1.19 μm/pixel through a 10x objective lens and is 0.72 μm/pixel through a 20x lens. A smooth-walled wedge channel was fabricated to study the generation and relaxation of water films in the non-wetting phase of air. The effect of films on contact angle, interfacial area per volume (IAV), and capillary pressure - saturation (Pc - Sw) hysteresis were also investigated. Micromodels were fabricated using a negative photoresist (SU-8) sandwiched between two cover glasses. An all-SU-8 smooth-walled wedge channel was fabricated by laser direct-writing two-photon polymerization, 100 μm wide at the outlet and 20 μm at the inlet with a constant aperture of 40 μm. A laser scanning confocal microscope was used to image the wetting (water) and non-wetting (air) phase distributions by labeling the wetting phase with a fluorophore, Alex Fluor-488, 1.0% by wieght. The 3D air-water interfaces were imaged and then reconstructed using a stack of confocal images. The samples were initially saturated with water, the wetting phase. A series of drainage and imbibition cycles were performed by incrementing or decrementing the air pressure. At each pressure, the system was allowed to equilibrate and then a stack of scans in depth was collected to acquire the 3D fluid distribution for the given pressure. The confocal images were

  3. Comparison study between the effects of different terms contributing to viscous dissipation in saturated porous media

    KAUST Repository

    Salama, Amgad

    2013-02-01

    Some sort of controversy is associated with the problem of viscous dissipation in saturated porous media for which we try to present a comparison study between the influences of the different terms contributing to this phenomenon. We consider viscous dissipation by studying the case of semi-infinite flat plate embedded in saturated porous medium and is kept at constant, higher temperature compared with the surrounding fluid. The fluid is induced to move upwards by natural convection during which viscous dissipation is considered. The boundary layer assumptions are considered to simplify the treatment and to highlight the influencing parameters. The behavior of temperature, and velocity fields in the neighborhood of the vertical flat plate were used to highlight the effects of these parameters. Three terms were considered to contribute to viscous dissipation, namely Darcy\\'s term, the Forchheimer term and Al-Hadharami\\'s term. Although there are no unanimous agreements between researchers to include the Forchhemier term in the dissipation function, some researchers argued it might have an indirect effect and hence for this sake and for completion purposes, we include it in this comparison study. Dimensional considerations reveal that Darcy\\'s term is influenced by Gebhart number, the Forchheimer term is controlled by the non-Darcy parameter and Al-Hadharami\\'s term is influenced by Darcy\\'s number. The governing, non-dimensional set of equations together with the imposed boundary conditions is numerically investigated by finite element method. The results for the details of the governing parameters are presented and investigated. It is found that the irreversible process of transforming the kinetic energy of the moving fluid to heat energy via the viscosity of the moving fluid (i.e., viscous dissipation) is very much influenced by the relative magnitude of these dimensionless parameters. © 2012 Elsevier Masson SAS. All rights reserved.

  4. Different Responses of Cardiac Cells to Saturated and Unsaturated Fatty Acids

    Directory of Open Access Journals (Sweden)

    I. Khodadadi

    2007-04-01

    Full Text Available Introduction & Objective: The link between dietary fat and coronary heart disease has attracted much attention since the effect of long chain fatty acids (LCFA on gene transcription has been established, which in part, these effects can be explained by the regulation of gene transcription. In this study, the P19CL6 cardiac cell line was targeted for the investigation of (i the effects of long chain fatty acids (LCFA and clofibrate on mRNA levels of specific lipid metabolism related genes, such as heart type fatty acid binding protein (H FABP and peroxisome proliferator activated receptors (PPAR,, in the P19CL6 cell line, and (ii to determine the effects of LCFAs and clofibrate on global transcriptome levels, using cDNA microarray analysis. Materials & Methods: After culturing P19CL6 cells with LCFAs or clofibrate, the total RNA was extracted and expression levels of H-FABP, PPAR, PPAR, and PPAR genes were determined by RT PCR. In addition, microarray analysis was used to compare global transcriptome profiles in P19CL6 cells cultured with different LCFAs or clofibrate.Results: LCFAs significantly increased the abundance of PPAR and PPAR. Moreover, microarray analysis showed the effects of linoleic and  linolenic acids and clofibrate were similar but differed from those of palmitic and oleic acids..Conclusion: These findings show cellular responses to polyunsaturated fatty acids differ from those observed with saturated and monounsaturated fatty acids.

  5. Mapping topsoil field-saturated hydraulic conductivity from point measurements using different methods

    Directory of Open Access Journals (Sweden)

    Braud Isabelle

    2017-09-01

    Full Text Available Topsoil field-saturated hydraulic conductivity, Kfs, is a parameter that controls the partition of rainfall between infiltration and runoff and is a key parameter in most distributed hydrological models. There is a mismatch between the scale of local in situ Kfs measurements and the scale at which the parameter is required in models for regional mapping. Therefore methods for extrapolating local Kfs values to larger mapping units are required. The paper explores the feasibility of mapping Kfs in the Cévennes-Vivarais region, in south-east France, using more easily available GIS data concerning geology and land cover. Our analysis makes uses of a data set from infiltration measurements performed in the area and its vicinity for more than ten years. The data set is composed of Kfs derived from infiltration measurements performed using various methods: Guelph permeameters, double ring and single ring infiltrotrometers and tension infiltrometers. The different methods resulted in a large variation in Kfs up to several orders of magnitude. A method is proposed to pool the data from the different infiltration methods to create an equivalent set of Kfs. Statistical tests showed significant differences in Kfs distributions in function of different geological formations and land cover. Thus the mapping of Kfs at regional scale was based on geological formations and land cover. This map was compared to a map based on the Rawls and Brakensiek (RB pedotransfer function (mainly based on texture and the two maps showed very different patterns. The RB values did not fit observed equivalent Kfs at the local scale, highlighting that soil texture alone is not a good predictor of Kfs.

  6. DETERMINATION OF SATURATION VAPOR PRESSURE OF LOW VOLATILE SUBSTANCES THROUGH THE STUDY OF EVAPORATION RATE BY THERMOGRAVIMETRIC ANALYSIS

    Directory of Open Access Journals (Sweden)

    R. V. Ralys

    2015-11-01

    Full Text Available Subject of Study.Research of vapor pressure of low volatile substances is a complicated problem due to both direct experimental implementation complexity and, most significantly, the issues faced correctness of the analysis and processing of experimental data. That is why it is usually required engaging the reference substances (with vapor pressures well studied. The latter drastically reduces the effectiveness of the experimental methods used and narrows their applicability. The paper deals with an approach to the evaporation process description (sublimation of low volatile substances based on molecular kinetic description in view of diffusive and convection processes. The proposed approach relies on experimental thermogravimetricfindingsina wide range of temperatures, flow rates ofthe purge gas and time. Method. A new approach is based on the calculation of the vapor pressure and uses the data about the speed of evaporation by thermogravimetric analysis depending on the temperature, the flow rate of the purge gas, and the evaporation time. The basis for calculation is the diffusion-kinetic description of the process of evaporation (mass loss of the substance from the exposed surface. The method is applicable to determine the thermodynamic characteristics for both the evaporation (the equilibrium liquid - vapor and sublimation (the equilibrium solid - vapor. We proposed the appropriate method of the experiment and analysis of its data in order to find the saturated vapor pressure of individual substances of low volatility. Main Results. The method has been tested on substances with insufficiently reliable and complete study of the thermodynamic characteristics but, despite this, are often used (because of the other data limitations as reference ones. The vaporization process (liquid-vapor has been studied for di-n-butyl phthalate C16H22O4 at 323,15–443,15 К, and sublimation for benzoic acid C7H6O2at 303,15–183,15 К. Both processes have

  7. Saturation transfer difference NMR and computational modeling of a sialoadhesin-sialyl lactose complex.

    Science.gov (United States)

    Bhunia, Anirban; Jayalakshmi, V; Benie, Andrew J; Schuster, Oliver; Kelm, Sørge; Rama Krishna, N; Peters, Thomas

    2004-01-22

    The siglecs are a family of I-type lectins binding to sialic acids on the cell surface. Sialoadhesin (siglec-1) is expressed at much higher levels in inflammatory macrophages and specifically binds to alpha-2,3-sialylated N-acetyl lactosamine residues of glycan chains. The terminal disaccharide alpha-D-Neu5Ac-(2-->3)-beta-D-Gal is thought to be the main epitope recognized by sialoadhesin. To understand the basis of this biological recognition reaction we combined NMR experiments with a molecular modeling study. We employed saturation transfer difference (STD) NMR experiments to characterize the binding epitope of alpha-2,3-sialylated lactose, alpha-D-Neu5Ac-(2-->3)-beta-D-Gal-(1-->4)-D-Glc 1 to sialoadhesin at atomic resolution. The experimental results were compared to a computational docking model and to X-ray data of a complex of sialyl lactose and sialoadhesin. The data reveal that sialoadhesin mainly recognizes the N-acetyl neuraminic acid and a small part of the galactose moiety of 1. The crystal structure of a complex of sialoadhesin with sialyl lactose 1 was used as a basis for a modeling study using the FlexiDock algorithm. The model generated was very similar to the original crystal structure. Therefore, the X-ray data were used to predict theoretical STD values utilizing the CORCEMA-STD protocol. The good agreement between experimental and theoretical STD values indicates that a combined modeling/STD NMR approach yields a reliable structural model for the complex of sialoadhesin with alpha-D-Neu5Ac-(2-->3)-beta-D-Gal-(1-->4)-D-Glc 1 in aqueous solution.

  8. Flow Properties in Saturated Soils from Differing Behaviour of Dispersive Seismic Velocity and Attenuation

    NARCIS (Netherlands)

    Ghose, R.; Zhubayev, A.

    2012-01-01

    A careful look into the pertinent models of poroelasticity reveals that in water-saturated sediments or soils, the seismic (P and S wave) velocity dispersion and attenuation in the low field-seismic frequency band (20-200 Hz) have a contrasting behaviour in the porosity-permeability domain.Taking

  9. Saturated and unsaturated flow through sloped compost filter beds of different particle sizes.

    Science.gov (United States)

    Petrell, R J; Gumulia, Anastasia

    2013-01-01

    Little is known about the hydraulics of sloped compost beds having active free and non-flowing zones, and used for runoff erosion and volume control, and heavy metal removal. Water sorption tests on yard waste compost indicated that water transfer between the two zones would be slow (6 hr for a 0.04 m rise). The free flowing zone in ≈1 m long sloped (15°) beds increased in depth (0.01-0.08 m) with decreasing particle size and increasing flow. Particle size and flow (0.08-0.3 L/s/m) affected bed stability. Drainage volume increased with flow while drainage time remained fairly constant. Saturated flow occurred depending on the particle size above 0.02-0.165 L/s/m. Data indicate that sheet runoff from low intensity storms would most likely create unsaturated but stable bed conditions. Concentrated flows as from downspouts would likely create saturated conditions and have to be managed to prevent washout. A model based on porous media theory indicated that flow regime under saturated flow is turbulent. Results can be used to design compost beds for various runoff rates and to develop a heavy metal sorption model.

  10. The Systemic Blood Pressure and Oxygen Saturation in Retinal Arterioles Predict the Effect of Intravitreal Anti-VEGF Treatment on Diabetic Maculopathy.

    Science.gov (United States)

    Bek, Toke; Jørgensen, Christina Mørup

    2016-10-01

    The advent of vascular endothelial VEGF antagonists has increased the therapeutic options for diabetic maculopathy considerably. However, there is a need to identify patients who respond favorably to the treatment from those in whom the treatment is less effective. The purpose of the present study was to test the hypothesis that the oxygen saturation in retinal vessels together with other risk factors can predict the effect of anti-VEGF treatment on diabetic maculopathy. In 73 eyes from 53 patients with center-involving diabetic macular edema, multiple linear regression was used to evaluate the predictive value of oxygen saturation in larger retinal vessels together with age, diabetes duration, diabetes type, hemoglobin A1c (HbA1c), mean arterial blood pressure (MAP), body mass index (BMI), previous retinal photocoagulation, visual acuity (VA), and central retinal thickness (CRT) before treatment as explanatory variables for VA and CRT after three monthly injections of anti-VEGF medication. Anti-VEGF treatment induced a significant increase in VA and a significant decrease in CRT, but no significant changes in the overall oxygen saturation of larger retinal vessels. Visual acuity and CRT before treatment contributed significantly to predicting the same variable after treatment. Additionally, MAP and the oxygen saturation in retinal arterioles before treatment contributed significantly to predicting VA and CRT after treatment. The MAP and oxygen saturation in retinal arterioles might potentially be included as parameters in risk models predicting the effect of anti-VEGF treatment in patients with diabetic maculopathy.

  11. The Phase Envelope of Multicomponent Mixtures in the Presence of a Capillary Pressure Difference

    DEFF Research Database (Denmark)

    Sandoval Lemus, Diego Rolando; Yan, Wei; Michelsen, Michael Locht

    2016-01-01

    , whereas the upper branch of the dew point shows an increase. The cricondentherm is shifted to a higher temperature. We also presented a mathematical analysis of the phase envelope shift due to capillary pressure based on linear approximations. The resulting linear approximation equations can predict...... for test mixtures with wide ranges of compositions at different capillary radii and vapor fractions. The calculation results show that the phase envelope changes everywhere except at the critical point. The bubble point and the lower branch of the dew point show a decrease in the saturation pressure...

  12. Membrane distillation against a pressure difference

    NARCIS (Netherlands)

    Keulen, L.; Ham, L.V. van der; Kuipers, N.J.M.; Hanemaaijer, J.H.; Vlugt, T.J.H.; Kjelstrup, S.

    2017-01-01

    Membrane distillation is an attractive technology for production of fresh water from seawater. The MemPower® concept, studied in this work, uses available heat (86 °C) to produce pressurized water (2.2 bar and 46 °C) by membrane distillation, which again can be used to power a turbine for

  13. Correction: Electrochemical Investigation of the Corrosion of Different Microstructural Phases of X65 Pipeline Steel under Saturated Carbon Dioxide Conditions. Materials 2015, 8, 2635–2649

    Directory of Open Access Journals (Sweden)

    Yuanfeng Yang

    2015-12-01

    Full Text Available In the published manuscript “Electrochemical Investigation of the Corrosion of Different Microstructural Phases of X65 Pipeline Steel under Saturated Carbon Dioxide Conditions. [...

  14. Enhanced signal dispersion in saturation transfer difference experiments by conversion to a 1D-STD-homodecoupled spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Martin-Pastor, Manuel; Vega-Vazquez, Marino [Universidade de Santiago de Compostela, Laboratorio Integral de Dinamica e Estructura de Biomoleculas Jose R. Carracido, Unidade de Resonancia Magnetica, Edificio CACTUS, RIAIDT (Spain); Capua, Antonia De [Seconda Universita degli Studi di Napoli, Dipartimento di Scienze Ambientali (Italy); Canales, Angeles [Centro de Investigaciones Biologicas, CSIC, Departamento de Estructura y funcion de proteinas (Spain); Andre, Sabine; Gabius, Hans-Joachim [Ludwig-Maximilians-Universitaet, Institut fuer Physiologische Chemie, Tieraerztliche Fakultaet (Germany); Jimenez-Barbero, Jesus [Centro de Investigaciones Biologicas, CSIC, Departamento de Estructura y funcion de proteinas (Spain)], E-mail: JJbarbero@cib.csic.es

    2006-10-15

    The saturation transfer difference (STD) experiment is a rich source of information on topological aspects of ligand binding to a receptor. The epitope mapping is based on a magnetization transfer after signal saturation from the receptor to the ligand, where interproton distances permit this process. Signal overlap in the STD spectrum can cause difficulties to correctly assign and/or quantitate the measured enhancements. To address this issue we report here a modified version of the routine experiment and a processing scheme that provides a 1D-STD homodecoupled spectrum (i.e. an experiment in which all STD signals appear as singlets) with line widths similar to those in original STD spectrum. These refinements contribute to alleviate problems of signal overlap. The experiment is based on 2D-J-resolved spectroscopy, one of the fastest 2D experiments under conventional data sampling in the indirect dimension, and provides excellent sensitivity, a key factor for the difference experiments.

  15. Neuroprotection of hyperbaric oxygen therapy in sub-acute traumatic brain injury: not by immediately improving cerebral oxygen saturation and oxygen partial pressure

    Directory of Open Access Journals (Sweden)

    Bao-chun Zhou

    2016-01-01

    Full Text Available Although hyperbaric oxygen (HBO therapy can promote the recovery of neural function in patients who have suffered traumatic brain injury (TBI, the underlying mechanism is unclear. We hypothesized that hyperbaric oxygen treatment plays a neuroprotective role in TBI by increasing regional transcranial oxygen saturation (rSO2 and oxygen partial pressure (PaO2. To test this idea, we compared two groups: a control group with 20 healthy people and a treatment group with 40 TBI patients. The 40 patients were given 100% oxygen of HBO for 90 minutes. Changes in rSO2 were measured. The controls were also examined for rSO2 and PaO2 , but received no treatment. rSO2 levels in the patients did not differ significantly after treatment, but levels before and after treatment were significantly lower than those in the control group. PaO2 levels were significantly decreased after the 30-minute HBO treatment. Our findings suggest that there is a disorder of oxygen metabolism in patients with sub-acute TBI. HBO does not immediately affect cerebral oxygen metabolism, and the underlying mechanism still needs to be studied in depth.

  16. Optimization of pressurized liquid extraction (PLE) for rapid determination of mineral oil saturated (MOSH) and aromatic hydrocarbons (MOAH) in cardboard and paper intended for food contact.

    Science.gov (United States)

    Moret, Sabrina; Sander, Maren; Purcaro, Giorgia; Scolaro, Marianna; Barp, Laura; Conte, Lanfranco S

    2013-10-15

    Packaging can represent a primary source of food contamination with mineral oil saturated hydrocarbons (MOSH) and aromatic hydrocarbons (MOAH), especially when recycled cardboard or mineral oil based printing inks are used. A pressurized liquid extraction (PLE) method, followed by on-line LC-GC analysis, has been optimized for rapid mineral oil determination in cardboard and paper samples. The proposed method involves extraction with hexane (2 cycles) at 60°C for 5 min, and allows for the processing of up to 6 samples in parallel with minimal sample manipulation and solvent consumption. It gave good repeatability (coefficient of variation lower than 5%) and practically quantitative extraction yield (less than 2% of the total contamination found in a third separate cycle). The method was applied to different cardboards and paper materials intended for food contact. Results obtained were similar to those obtained by applying classical solvent extraction with hexane/ethanol 1:1 (v/v) as described by Lorenzini et al. [20]. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Methane hydrate pore saturation evaluation from geophysical logging and pressure core analysis, at the first offshore production test site in the eastern Nankai Trough, Japan

    Science.gov (United States)

    Fujii, T.; Suzuki, K.; Takayama, T.; Konno, Y.; Yoneda, J.; Egawa, K.; Ito, T.; Nagao, J.

    2013-12-01

    On March 2013, the first offshore production test form methane hydrate (MH) concentrated zone (MHCZ) was conducted by the Research Consortium for Methane Hydrate Resource Development in Japan (MH21) at the AT1 site located in the north-western slope of Daini-Atsumi Knoll in the eastern Nankai Trough, Japan. Before the production test, extensive geophysical logging and pressure coring using Hybrid Pressure Coring System were conducted in 2012 at monitoring well (AT1-MC) and coring well (AT1-C), in order to obtain basic information for the MH reservoir characterization. MH pore saturation (Sh) is one of the important basic parameters not only for reservoir characterization, but also the resource assessment. However, precise evaluation of Sh from geophysical logging is still challenging technical issue. The MHCZ confirmed by the geophysical logging at AT1-MC has a turbidite assemblage (from several tens of centimeters to a few meters) with 60 m of gross thickness; it is composed of lobe/sheet type sequences in the upper part, and relatively thick channel sand sequences in the lower part. In this study, the Sh evaluated from geophysical logging data were compared with those evaluated from pressure core analysis. Resistivity logs and nuclear magnetic resonance (NMR) log were used for the Sh evaluation by geophysical logging. Standard Archie equation was applied for Sh evaluation from resistivity log, while density magnetic resonance (DMR) method was used for Sh evaluation from NMR log. The Sh from pressure core samples were evaluated using the amount of dissociated gas volume, together with core sample bulk volume, measured porosity, net sand intervals, and assumed methane solubility in pore water. In the upper part of the MHCZ, Sh estimated from resistivity log showed distinct difference in value between sand and mud layers, compared to Sh from NMR log. Resistivity log has higher vertical resolution than NMR log, so it is favorable for these kinds of thin bed

  18. Blood pressure variations in Subjects with different Haemoglobin ...

    African Journals Online (AJOL)

    Dr Olaleye Samuel

    variations in blood pressures as well as relating the blood pressures in different haemoglobin. (HB) genotypes to each other. Blood pressures in 20 steady and crisis states SCD patients respectively with 40 apparently healthy heterozygous HB AS and HB AA genotype (age and sex –matched). They were aged between 20 ...

  19. New porcine test-model reveals remarkable differences between algorithms for spectrophotometrical haemoglobin saturation measurements with VLS

    DEFF Research Database (Denmark)

    Gade, John; Greisen, Gorm

    2016-01-01

    UNLABELLED: The study created an 'ex vivo' model to test different algorithms for measurements of mucosal haemoglobin saturation with visible light spectrophotometry (VLS). The model allowed comparison between algorithms, but it also allowed comparison with co-oximetry using a 'gold standard......-oxygenated state ranged from  -32.8 to  +29.9 percentage points and from  -5.0 to  +9.2 percentage points, respectively. CONCLUSION: the algorithms showed remarkable in-between differences when tested on raw-spectra from an 'ex vivo' model. All algorithms had bias, more marked at high oxygenation than low...

  20. One-dimensional pore pressure diffusion of different grain-fluid mixtures

    Science.gov (United States)

    von der Thannen, Magdalena; Kaitna, Roland

    2015-04-01

    During the release and the flow of fully saturated debris, non-hydrostatic fluid pressure can build up and probably dissipate during the event. This excess fluid pressure has a strong influence on the flow and deposition behaviour of debris flows. Therefore, we investigate the influence of mixture composition on the dissipation of non-hydrostatic fluid pressures. For this we use a cylindrical pipe of acrylic glass with installed pore water pressure sensors in different heights and measure the evolution of the pore water pressure over time. Several mixtures with variable content of fine sediment (silt and clay) and variable content of coarse sediment (with fixed relative fractions of grains between 2 and 32 mm) are tested. For the fines two types of clay (smectite and kaolinite) and loam (Stoober Lehm) are used. The analysis is based on the one-dimensional consolidation theory which uses a diffusion coefficient D to model the decay of excess fluid pressure over time. Starting from artificially induced super-hydrostatic fluid pressures, we find dissipation coefficients ranging from 10-5 m²/s for liquid mixtures to 10-8 m²/s for viscous mixtures. The results for kaolinite and smectite are quite similar. For our limited number of mixtures the effect of fines content is more pronounced than the effect of different amounts of coarse particles.

  1. Capillary pressure-saturation relations for supercritical CO2 and brine in limestone/dolomite sands: implications for geologic carbon sequestration in carbonate reservoirs.

    Science.gov (United States)

    Wang, Shibo; Tokunaga, Tetsu K

    2015-06-16

    In geologic carbon sequestration, capillary pressure (Pc)-saturation (Sw) relations are needed to predict reservoir processes. Capillarity and its hysteresis have been extensively studied in oil-water and gas-water systems, but few measurements have been reported for supercritical (sc) CO2-water. Here, Pc-Sw relations of scCO2 displacing brine (drainage), and brine rewetting (imbibition) were studied to understand CO2 transport and trapping behavior under reservoir conditions. Hysteretic drainage and imbibition Pc-Sw curves were measured in limestone sands at 45 °C under elevated pressures (8.5 and 12.0 MPa) for scCO2-brine, and in limestone and dolomite sands at 23 °C (0.1 MPa) for air-brine using a new computer programmed porous plate apparatus. scCO2-brine drainage and imbibition curves shifted to lower Pc relative to predictions based on interfacial tension, and therefore deviated from capillary scaling predictions for hydrophilic interactions. Fitting universal scaled drainage and imbibition curves show that wettability alteration resulted from scCO2 exposure over the course of months-long experiments. Residual trapping of the nonwetting phases was determined at Pc = 0 during imbibition. Amounts of trapped scCO2 were significantly larger than for those for air, and increased with pressure (depth), initial scCO2 saturation, and time. These results have important implications for scCO2 distribution, trapping, and leakage potential.

  2. Experimental studies on the enhanced flow boiling heat transfer and pressure drop of organic fluid with high saturation temperature in vertical porous coated tube

    Science.gov (United States)

    Yang, Dong; Shen, Zhi; Chen, Tingkuan; Zhou, Chenn Q.

    2013-07-01

    The characteristics of flow boiling heat transfer and pressure drop of organic fluid with high saturation temperature in a vertical porous coated tube are experimentally studied in this paper. The experiments are performed at evaporation pressure of 0.16-0.31MPa, mass flux of 390-790kg/m2s, and vapor quality of 0.06-0.58. The variations of heat transfer coefficient and pressure drop with vapor quality are measured and compared to the results of smooth tube. Boiling curves are generated at mass flux of 482 and 675kg/m2s. The experimental results indicate that the heat transfer coefficients of the porous tube are 1.8-3.5 times those of smooth tube, and that the frictional pressure drops of the porous tube are 1.1-2.9 times those of smooth tube. The correlations for heat transfer coefficient and frictional pressure drop are derived, in which the effect of fluid molecular weight is included. The experiments show that significant heat transfer enhancement is accompanied by a little pressure drop penalty, the application of the porous coated tube is promising in the process industries.

  3. Molar Heat Capacity (Cv) for Saturated and Compressed Liquid and Vapor Nitrogen from 65 to 300 K at Pressures to 35 MPa.

    Science.gov (United States)

    Magee, J W

    1991-01-01

    Molar heat capacities at constant volume (Cv ,) for nitrogen have been measured with an automated adiabatic calorimeter. The temperatures ranged from 65 to 300 K, while pressures were as high as 35 MPa. Calorimetric data were obtained for a total of 276 state conditions on 14 isochores. Extensive results which were obtained in the saturated liquid region (Cv((2)) and Cσ ) demonstrate the internal consistency of the Cv (ρ,T) data and also show satisfactory agreement with published heat capacity data. The overall uncertainty of the Cv values ranges from 2% in the vapor to 0.5% in the liquid.

  4. Kinetics and dynamics of nanosecond streamer discharge in atmospheric-pressure gas bubble suspended in distilled water under saturated vapor pressure conditions

    KAUST Repository

    Sharma, Ashish

    2016-09-08

    We perform computational studies of nanosecond streamer discharges generated in helium bubbles immersed in distilled water under atmospheric pressure conditions. The model takes into account the presence of water vapor in the gas bubble for an accurate description of the discharge kinetics. We find that the dynamic characteristics of the streamer discharge are different at low and high positive trigger voltages with the axial streamer evolution dominant for low voltages and a surface hugging mode favored for high voltages. We also find a substantial difference in initiation, transition and evolution stages of discharge for positive and negative trigger voltages with the volumetric distribution of species in the streamer channel much more uniform for negative trigger voltages on account of the presence of multiple streamers. We observe that the presence of water vapor does not affect the breakdown voltage even for oversaturated conditions but significantly influences the composition of dominant species in the trail of the streamer as well as the flux of the dominant species on the bubble surface. © 2016 IOP Publishing Ltd.

  5. Kinetics and dynamics of nanosecond streamer discharge in atmospheric-pressure gas bubble suspended in distilled water under saturated vapor pressure conditions

    Science.gov (United States)

    Sharma, Ashish; Levko, Dmitry; Raja, Laxminarayan L.; Cha, Min Suk

    2016-10-01

    We perform computational studies of nanosecond streamer discharges generated in helium bubbles immersed in distilled water under atmospheric pressure conditions. The model takes into account the presence of water vapor in the gas bubble for an accurate description of the discharge kinetics. We find that the dynamic characteristics of the streamer discharge are different at low and high positive trigger voltages with the axial streamer evolution dominant for low voltages and a surface hugging mode favored for high voltages. We also find a substantial difference in initiation, transition and evolution stages of discharge for positive and negative trigger voltages with the volumetric distribution of species in the streamer channel much more uniform for negative trigger voltages on account of the presence of multiple streamers. We observe that the presence of water vapor does not affect the breakdown voltage even for oversaturated conditions but significantly influences the composition of dominant species in the trail of the streamer as well as the flux of the dominant species on the bubble surface.

  6. Research experiments on pressure-difference sensors with ferrofluid

    Energy Technology Data Exchange (ETDEWEB)

    Ruican, Hao, E-mail: haoruican@163.com [School of Mechanical Engineering, Beijing Polytechnic, Beijing 100176 (China); Huagang, Liu; Wen, Gong; Na, Zhang [School of Mechanical Engineering, Beijing Polytechnic, Beijing 100176 (China); Ruixiao, Hao [Civil and Architectural Engineering Institute of CCCC-FHEB Co., Ltd., Beijing 101102 (China)

    2016-10-15

    Ferrofluid has distinctive properties and can be applied in many industrial uses, especially in sensors. The principles of pressure-difference sensors with ferrofluid were illustrated and experiments were demonstrated. Four types of ferrofluids with different concentrations were selected for the experiments performed. Then, the parameters of ferrofluid, such as density and magnetization, were measured. The magnetization curves of the ferrofluid were sketched. Four U tubes with different diameters were designed and built. Experiments were conducted to analyze the impacts of tube diameter and ferrofluid concentration on the output voltage/pressure difference performance. According to the experiment results, the tube diameter has little effect on the sensor output voltage. With the concentration of ferrofluid increasing, the output voltage and sensitivity of the pressure-difference sensor increases. The measurable range of the sensor also increases with the increasing concentration of ferrofluid. The workable range and the sensitivity of the designed sensor were (−2000~+2000)Pa and 1.26 mV/Pa, respectively. - Highlights: • The principle of pressure difference sensor with ferrofluid was illustrated. • The parameters of ferrofluid, such as density and magnetization, were measured. The magnetization curves of the ferrofluid were sketched. • Four series of U tubes with different diameter were designed and manufactured. • The experiments were made to analyze the factors of the tube diameter and the concentration of ferrofluid on the output-input pressure difference. • The sensitivity of the pressure difference sensor with ferrofluid was studied and the corresponding conclusions were obtained.

  7. Stability Of Superposed Fluids Through Magnetic Field With Suspended Particles Of Different Permeability Saturated Through Porous Layer

    Science.gov (United States)

    Singh, M.

    2015-12-01

    The instability of plane interface between two superposed Rivlin-Ericksen elastico-viscous fluids saturated through a porous medium has been studied to include the suspended (dust) particles effect. Following the linearized stability theory and normal mode analysis the dispersion relation is obtained. For stationary convection, the Rivlin-Ericksen elastico-viscous fluid behaves like Newtonian fluids. It found that for a potentially stable arrangement the Rivlin-Ericksen elastico-viscous fluid of different permeabilities in the presence of suspended particles in a porous medium is stable, whereas in a potentially unstable case instability of the system occurs. In the presence of a magnetic field for a potentially stable arrangement the system is always stable and for the potentially unstable arrangement, the magnetic field succeeds in stabilizing certain wave-number band which was unstable in the absence of the magnetic field.

  8. Saturation transfer difference nuclear magnetic resonance titrations reveal complex multistep-binding of l-fucose to norovirus particles.

    Science.gov (United States)

    Mallagaray, Alvaro; Rademacher, Christoph; Parra, Francisco; Hansman, Grant; Peters, Thomas

    2017-01-01

    Recently, combined nuclear magnetic resonance (NMR), native mass spectrometry (MS) and X-ray crystallographic studies have demonstrated that binding of histo-blood group antigens (HBGAs) to norovirus capsid protein (P-dimers) is a cooperative process involving four binding pockets. Here, we show that binding to norovirus virus-like particles (VLPs) is even more complex. We performed saturation transfer difference (STD) NMR titration experiments with two representative genotypes of norovirus VLPs using l-fucose as a minimal HBGA. Compared to titrations with P-dimers, the corresponding binding isotherms reflect at least six distinct binding events. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. Racial differences in hypertension: implications for high blood pressure management.

    Science.gov (United States)

    Lackland, Daniel T

    2014-08-01

    The racial disparity in hypertension and hypertension-related outcomes has been recognized for decades with African Americans with greater risks than Caucasians. Blood pressure levels have consistently been higher for African Americans with an earlier onset of hypertension. Although awareness and treatment levels of high blood pressure have been similar, racial differences in control rates are evident. The higher blood pressure levels for African Americans are associated with higher rates of stroke, end-stage renal disease and congestive heart failure. The reasons for the racial disparities in elevated blood pressure and hypertension-related outcomes risk remain unclear. However, the implications of the disparities of hypertension for prevention and clinical management are substantial, identifying African American men and women with excel hypertension risk and warranting interventions focused on these differences. In addition, focused research to identify the factors attributed to these disparities in risk burden is an essential need to address the evidence gaps.

  10. Seven-Day Mortality Can Be Predicted in Medical Patients by Blood Pressure, Age, Respiratory Rate, Loss of Independence, and Peripheral Oxygen Saturation (the PARIS Score)

    DEFF Research Database (Denmark)

    Brabrand, Mikkel; Lassen, Annmarie Touborg; Knudsen, Torben

    2015-01-01

    . The outcome was defined as seven-day all-cause mortality. 76 patients (2.5%) met the endpoint in the development cohort, 57 (2.0%) in the first validation cohort, and 111 (4.3%) in the second. Systolic blood Pressure, Age, Respiratory rate, loss of Independence, and peripheral oxygen Saturation were...... with a PARIS score ≥3, sensitivity was 62.5-74.0%, specificity 85.9-91.1%, positive predictive value 11.2-17.5%, and negative predictive value 98.3-99.3%. Patients with a score ≤1 had a low mortality (≤1%); with 2, intermediate mortality (2-5%); and ≥3, high mortality (≥10%). CONCLUSIONS: Seven-day mortality...... can be predicted upon admission with high sensitivity and specificity and excellent negative predictive values....

  11. Plantar Pressure Variation during Jogging with Different Heel Height

    Directory of Open Access Journals (Sweden)

    Y. D. Gu

    2013-01-01

    Full Text Available This paper presents the key testing and analysis results of an investigation on the effect of heel height on the plantar pressure over different foot areas in jogging. It is important in improving the understanding of jogging with high heels and damage/injury prevention. It can also potentially guide the development of suitable/adaptive exercise schemes in between daily activities with high heels. In this work, plantar pressure data were collected from 10 habituated healthy female subjects (aged 21–25 years at their natural jogging speed with three different conditions: flat heeled shoes (0.8 cm, low heeled shoes (4.0 cm, and high heeled shoes (6.6 cm. Data analysis showed significantly differences in plantar pressure distribution associated with the heel heights with increased pressure in the first metatarsal region and decreased pressure in the lateral metatarsal and midfoot sections. However, there is no significant alteration of plantar pressure in the central area of the forefoot with jogging gait.

  12. Differences in predatory pressure on terrestrial snails by birds and ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Biosciences; Volume 36; Issue 4. Differences in predatory ... Articles Volume 36 Issue 4 September 2011 pp 691-699 ... larger individuals. Significant differences in their predatory pressure can influence the evolution and maintenance of shell size and polymorphism of shell colouration in snails.

  13. Differences in foot pressures between Caucasians and Indians.

    Science.gov (United States)

    Putti, A B; Arnold, G P; Abboud, R J

    2010-12-01

    Indians are the largest single ethnic minority group in the United Kingdom and form more than one million of the current population. No studies have investigated foot pressure differences between Caucasians and Indians. The aim of our study was to investigate the in-shoe pressure differences in Caucasians and Indians using the Pedar(®)-m (Novel GmbH, Germany). The study included 12 Caucasians and 21 Indians. Peak pressure (PP), contact area (CA), contact time (CT), pressure-time integral (PTI), force-time integral (FTI), instant of peak pressure (IPP), maximum force (MaxF) and mean force (MeanF) were recorded. Caucasians had higher significant PP compared to Indians under the heel (293 kPa vs. 251 kPa; Prace groups. The PTI was statistically significantly higher in Caucasians in the region of the 1st metatarsal head (79 kPas vs. 62 kPas; P=0.03) and 5th metatarsal head (58 kPas vs. 44 kPas; P=0.03). There were no significant differences among CT, FTI, IPP, MaxF and MeanF among them. The PP under the heel, 1st, 2nd, 3rd and 5th metatarsal heads and the PTI under the 1st and 5th metatarsal heads in Caucasians is higher than in Indians. There is no difference in the CA. Copyright © 2009 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

  14. Estimation of mean arterial pressure from the oscillometric cuff pressure: comparison of different techniques.

    Science.gov (United States)

    Zheng, Dingchang; Amoore, John N; Mieke, Stephan; Murray, Alan

    2011-01-01

    Mean arterial pressure (MAP) is determined in most automated oscillometric blood pressure devices, but its derivation has been little studied. In this research, different techniques were studied and compared with the auscultatory technique. Auscultatory systolic and diastolic blood pressure (SBP and DBP) were obtained in 55 healthy subjects by two trained observers, and auscultatory MAP was estimated. Automated MAP was determined by six techniques from oscillometric cuff pressures recorded digitally and simultaneously during manual measurement. MAPs were derived from the peak and foot of the largest oscillometric pulse, and from time domain curves fitted to the sequence of oscillometric pulse amplitudes (4th order and three versions of the 6th order polynomial curve). The agreement between automated and auscultatory MAPs was assessed. Compared with the auscultatory MAP, the automated MAP from the baseline cuff pressure at the peak of the 6th order polynomial curve had the smallest mean paired difference (-1.0 mmHg), and smallest standard deviation of paired differences (3.7 mmHg). These values from the peak of the largest oscillometric pulse were -1.3 and 6.2 mmHg, respectively. Determining MAP from a model of the oscillometric pulse waveform had the smallest differences from the manual auscultatory technique.

  15. The acute effects of a single session of expiratory muscle strength training on blood pressure, heart rate, and oxygen saturation in healthy adults

    Directory of Open Access Journals (Sweden)

    Helena eLaciuga

    2012-03-01

    Full Text Available Expiratory Muscle Strength Training (EMST is a rehabilitative program that has been tested for outcomes related to respiratory muscle strength, cough, swallow and voice function in healthy young adult, elderly individuals, and in patients with progressive neurodegenerative disease. Because EMST has been used in patient care, the associated cardiovascular responses during EMST are of importance. This study investigated the changes in systolic blood pressure (SBP, diastolic blood pressure (DBP, heart rate (HR, and oxygen saturation (SpO2 during one session of EMST in healthy, young adults as a preliminary study of device safety. Thirty-one participants completed a single session of 25 trials with the EMST device. Valsalva maneuvers were performed at the beginning and at the end of the EMST trials for task comparison. The SBP, DBP, HR, and SpO2 were recorded at the baseline prior to the EMST task and Valsalva, after 12 trials using the EMST device, and after five minutes of rest following the EMST session. A mixed linear model tested for changes across the six time points. The results indicated no significant change of SBP, DBP, HR, or SpO2 during or following the EMST trials or after performing the Valsalva maneuver. The results suggest that EMST does not elicit significant fluctuations of BP, HR, and SpO2 in healthy young adults even when considering the effects of covariates on the outcomes measures.

  16. Effects of different fat sources (saturated and unsaturated) on reproductive performance and biological indices of ewes during flushing period.

    Science.gov (United States)

    Asgari Safdar, Amir Hossein; Sadeghi, Ali Asghar; Chamani, Mohammad

    2017-07-07

    This study was conducted to evaluate the effect of feeding different sources of fat during flushing period on the reproductive performance, lambing percent, and twin numbers of Afshari ewes. A total of 84 ewes (mean weight 48 ± 3 kg; age: 3-4 years) were divided into seven groups of 12 animals and received flushing-specific rations for 5 weeks. The control group just received a basic ration (non-flushing). Lipid sources were calcium salt of palm oil (CaP), pure palm oil (PO), calcium salt of flaxseed (CaFL), calcium salt of sunflower oil (CaSF), flaxseed oil (FLO), and sunflower oil (SFO). Estrous cycles were synchronized in all ewes using 14-day CIDRs followed by 400-IU PMSG injection at the time of CIDR removal. Fertility and lambing percent were higher in ewes fed with diets containing calcium salts of flaxseed and SFO, as compared to other treatments. Total number of lambs in flushing treatments was significantly higher than that in the control group (p saturated and unsaturated fatty acids, especially in their CSFA forms during flushing period, could improve the reproduction problems induced by progesterone deficiency, lack of durability of the fetus due to hormonal instability, and abortion control factors.

  17. The solid-liquid phase diagrams of binary mixtures of even saturated fatty acids differing by six carbon atoms

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Mariana C. [LPT, Department of Chemical Process, School of Chemical Engineering, University of Campinas, UNICAMP, P.O. Box 6066, 13083-970, Campinas-SP (Brazil); EXTRAE, Department of Food Engineering, Faculty of Food Engineering, University of Campinas, UNICAMP, P.O. Box 6121, 13083-862, Campinas-SP (Brazil); CICECO, Departamento de Quimica da Universidade de Aveiro, 3810-193 Aveiro (Portugal); Rolemberg, Marlus P. [DETQI, Department of Chemical Technology, Federal University of Maranhao (UFMA), Sao Luis, Maranhao (Brazil); Meirelles, Antonio J.A. [EXTRAE, Department of Food Engineering, Faculty of Food Engineering, University of Campinas, UNICAMP, P.O. Box 6121, 13083-862, Campinas-SP (Brazil); Coutinho, Joao A.P. [CICECO, Departamento de Quimica da Universidade de Aveiro, 3810-193 Aveiro (Portugal); Kraehenbuehl, M.A., E-mail: mak@feq.unicamp.br [LPT, Department of Chemical Process, School of Chemical Engineering, University of Campinas, UNICAMP, P.O. Box 6066, 13083-970, Campinas-SP (Brazil)

    2009-12-10

    This study was aimed at using the solid-liquid phase diagrams for three binary mixtures of saturated fatty acids, especially the phase transitions below the liquidus line. These mixtures are compounded by caprylic acid (C{sub 8:0}) + myristic acid (C{sub 14:0}), capric acid (C{sub 10:0}) + palmitic acid (C{sub 16:0}), lauric acid (C{sub 12:0}) + stearic acid (C{sub 18:0}), differing by six carbon atoms between carbon chains. The phase diagrams were obtained by differential scanning calorimetry (DSC). The polarized light microscopy was used to complement the characterization for a full grasp of the phase diagram. Not only do these phase diagrams present peritectic and eutectic reactions, but also metatectic reactions, due to solid-solid phase transitions common, in fatty acids. These findings have contributed to the elucidation of the phase behavior of these important biochemical molecules with implications in various industrial production.

  18. Electrochemical Investigation of the Corrosion of Different Microstructural Phases of X65 Pipeline Steel under Saturated Carbon Dioxide Conditions

    Directory of Open Access Journals (Sweden)

    Yuanfeng Yang

    2015-05-01

    Full Text Available The aim of this research was to investigate the influence of metallurgy on the corrosion behaviour of separate weld zone (WZ and parent plate (PP regions of X65 pipeline steel in a solution of deionised water saturated with CO2, at two different temperatures (55 °C and 80 °C and at initial pH~4.0. In addition, a non-electrochemical immersion experiment was also performed at 80 °C in CO2, on a sample portion of X65 pipeline containing part of a weld section, together with adjacent heat affected zones (HAZ and parent material. Electrochemical impedance spectroscopy (EIS was used to evaluate the corrosion behaviour of the separate weld and parent plate samples. This study seeks to understand the significance of the different microstructures within the different zones of the welded X65 pipe in CO2 environments on corrosion performance; with particular attention given to the formation of surface scales; and their composition/significance. The results obtained from grazing incidence X-ray diffraction (GIXRD measurements suggest that, post immersion, the parent plate substrate is scale free, with only features arising from ferrite (α-Fe and cementite (Fe3C apparent. In contrast, at 80 °C, GIXRD from the weld zone substrate, and weld zone/heat affected zone of the non-electrochemical sample indicates the presence of siderite (FeCO3 and chukanovite (Fe2CO3(OH2 phases. Scanning Electron Microscopy (SEM on this surface confirmed the presence of characteristic discrete cube-shaped crystallites of siderite together with plate-like clusters of chukanovite.

  19. [Comparison of different continuous positive airway pressure titration methods for obstructive sleep apnea hypopnea syndrome].

    Science.gov (United States)

    Li, Jingjing; Ye, Jingying; Zhang, Peng; Kang, Dan; Cao, Xin; Zhang, Yuhuan; Ding, Xiu; Zheng, Li; Li, Hongguang; Bian, Qiuli

    2014-10-01

    To explore whether there were differences between the results of automatic titration and the results of manual titration for positive airway pressure treatment in patients with obstructive sleep apnea hypopnea syndrome (OSAHS) and its influencing factors, the results might provide a theoretical basis for the rational use of two pressure titration methods. Sixty one patients with OSAHS were included in this study. All patients underwent a manual titration and an automatic titration within one week. The clinical informations, polysomnography data, and the results of both two titration of all patients were obtained for analysis. The overall apnea/hypopnea index was (63.1 ± 17.7)/h, with a range of 14.9/h to 110.4/h. The treatment pressure of manual titration was (8.4 ± 2.1) cmH(2)O, which was significantly lower than the treatment pressure of automatic titration, (11.5 ± 2.7) cmH(2)O (t = -9.797, P titration and manual titration), it was found that the pressure of automatic titration was significantly higher in patients with a ΔP > 3 cmH(2)O than in patients with a ΔP ≤ 3 cmH(2)O, which was (13.3 ± 2.3) cmH(2)O vs (10.0 ± 2.0) cmH(2)O (t = -6.159, P titration between these two groups, which was (8.6 ± 2.4) cmH(2)O vs (8.3 ± 2.0)cmH(2)O (P > 0.05). There was no significant difference in age, body mass index, neck circumference, abdomen circumference, apnea hypopnea index, and arterial oxygen saturation between these two groups. The treatment pressure of automatic titration is usually higher than that of manual titration. For patients with a high treatment pressure which is derived from automatic titration, a suggestion about manual titration could be given to decrease the potential treatment pressure of continuous positive airway pressure, which may be helpful in improving the comfortableness and the compliance of this treatment.

  20. Diving under a microscope--a new simple and versatile in vitro diving device for fluorescence and confocal microscopy allowing the controls of hydrostatic pressure, gas pressures, and kinetics of gas saturation.

    Science.gov (United States)

    Wang, Qiong; Belhomme, Marc; Guerrero, François; Mazur, Aleksandra; Lambrechts, Kate; Theron, Michaël

    2013-06-01

    How underwater diving effects the function of the arterial wall and the activities of endothelial cells is the focus of recent studies on decompression sickness. Here we describe an in vitro diving system constructed to achieve real-time monitoring of cell activity during simulated dives under fluorescent microscopy and confocal microscopy. A 1-mL chamber with sapphire windows on both sides and located on the stage of an inverted microscope was built to allow in vitro diving simulation of isolated cells or arteries in which activities during diving are monitored in real-time via fluorescent microscopy and confocal microscopy. Speed of compression and decompression can range from 20 to 2000 kPa/min, allowing systemic pressure to range up to 6500 kPa. Diving temperature is controlled at 37°C. During air dive simulation oxygen partial pressure is optically monitored. Perfusion speed can range from 0.05 to 10 mL/min. The system can support physiological viability of in vitro samples for real-time monitoring of cellular activity during diving. It allows regulations of pressure, speeds of compression and decompression, temperature, gas saturation, and perfusion speed. It will be a valuable tool for hyperbaric research.

  1. Automatic algorithm for monitoring systolic pressure variation and difference in pulse pressure.

    Science.gov (United States)

    Pestel, Gunther; Fukui, Kimiko; Hartwich, Volker; Schumacher, Peter M; Vogt, Andreas; Hiltebrand, Luzius B; Kurz, Andrea; Fujita, Yoshihisa; Inderbitzin, Daniel; Leibundgut, Daniel

    2009-06-01

    Difference in pulse pressure (dPP) reliably predicts fluid responsiveness in patients. We have developed a respiratory variation (RV) monitoring device (RV monitor), which continuously records both airway pressure and arterial blood pressure (ABP). We compared the RV monitor measurements with manual dPP measurements. ABP and airway pressure (PAW) from 24 patients were recorded. Data were fed to the RV monitor to calculate dPP and systolic pressure variation in two different ways: (a) considering both ABP and PAW (RV algorithm) and (b) ABP only (RV(slim) algorithm). Additionally, ABP and PAW were recorded intraoperatively in 10-min intervals for later calculation of dPP by manual assessment. Interobserver variability was determined. Manual dPP assessments were used for comparison with automated measurements. To estimate the importance of the PAW signal, RV(slim) measurements were compared with RV measurements. For the 24 patients, 174 measurements (6-10 per patient) were recorded. Six observers assessed dPP manually in the first 8 patients (10-min interval, 53 measurements); no interobserver variability occurred using a computer-assisted method. Bland-Altman analysis showed acceptable bias and limits of agreement of the 2 automated methods compared with the manual method (RV: -0.33% +/- 8.72% and RV(slim): -1.74% +/- 7.97%). The difference between RV measurements and RV(slim) measurements is small (bias -1.05%, limits of agreement 5.67%). Measurements of the automated device are comparable with measurements obtained by human observers, who use a computer-assisted method. The importance of the PAW signal is questionable.

  2. [Is blood pressure control different in women than in men?].

    Science.gov (United States)

    Oliveras, A; Sans-Atxer, L; Vázquez, S

    2015-01-01

    Blood pressure (BP) evolves with age; until the 50's it is higher in men than in women, equaling and even then increasing in women. The prevalence of controlled BP appears to be similar between the sexes, but the prevalence of cardiovascular disease is higher in women than in men. The possibility that BP influences the cardiovascular risk differently according to sex must therefore be considered. While some studies suggest no difference exists, others have shown evidence of an increased risk in women with respect to men despite equal BP. In this way, it seems that the measurement of ambulatory BP, but not office BP, would mark the differences in the association between BP-gender and cardiovascular risk. It should therefore be investigated the possibility of a different BP goal for women and men, especially by evaluating ambulatory BP. Copyright © 2015 SEHLELHA. Published by Elsevier España, S.L.U. All rights reserved.

  3. The impact of lactoferrin with different levels of metal saturation on the intestinal epithelial barrier function and mucosal inflammation.

    Science.gov (United States)

    Majka, Grzegorz; Więcek, Grażyna; Śróttek, Małgorzata; Śpiewak, Klaudyna; Brindell, Małgorzata; Koziel, Joanna; Marcinkiewicz, Janusz; Strus, Magdalena

    2016-12-01

    Translocation of bacteria, primarily Gram-negative pathogenic flora, from the intestinal lumen into the circulatory system leads to sepsis. In newborns, and especially very low birth weight infants, sepsis is a major cause of morbidity and mortality. The results of recently conducted clinical trials suggest that lactoferrin, an iron-binding protein that is abundant in mammalian colostrum and milk, may be an effective agent in preventing sepsis in newborns. However, despite numerous basic studies on lactoferrin, very little is known about how metal saturation of this protein affects a host's health. Therefore, the main objective of this study was to elucidate how iron-depleted, iron-saturated, and manganese-saturated forms of lactoferrin regulate intestinal barrier function via interactions with epithelial cells and macrophages. For these studies, a human intestinal epithelial cell line, Caco-2, was used. In this model, none of the tested lactoferrin forms induced higher levels of apoptosis or necrosis. There was also no change in the production of tight junction proteins regardless of lactoferrin metal saturation status. None of the tested forms induced a pro-inflammatory response in Caco-2 cells or in macrophages either. However, the various lactoferrin forms did effectively inhibit the pro-inflammatory response in macrophages that were activated with lipopolysaccharide with the most potent effect observed for apolactoferrin. Lactoferrin that was not bound to its cognate receptor was able to bind and neutralize lipopolysaccharide. Lactoferrin was also able to neutralize microbial-derived antigens, thereby potentially reducing their pro-inflammatory effect. Therefore, we hypothesize that lactoferrin supplementation is a relevant strategy for preventing sepsis.

  4. Investigating Gender Differences under Time Pressure in Financial Risk Taking.

    Science.gov (United States)

    Xie, Zhixin; Page, Lionel; Hardy, Ben

    2017-01-01

    There is a significant gender imbalance on financial trading floors. This motivated us to investigate gender differences in financial risk taking under pressure. We used a well-established approach from behavior economics to analyze a series of risky monetary choices by male and female participants with and without time pressure. We also used second to fourth digit ratio (2D:4D) and face width-to-height ratio (fWHR) as correlates of pre-natal exposure to testosterone. We constructed a structural model and estimated the participants' risk attitudes and probability perceptions via maximum likelihood estimation under both expected utility (EU) and rank-dependent utility (RDU) models. In line with existing research, we found that male participants are less risk averse and that the gender gap in risk attitudes increases under moderate time pressure. We found that female participants with lower 2D:4D ratios and higher fWHR are less risk averse in RDU estimates. Males with lower 2D:4D ratios were less risk averse in EU estimations, but more risk averse using RDU estimates. We also observe that men whose ratios indicate a greater prenatal exposure to testosterone exhibit a greater optimism and overestimation of small probabilities of success.

  5. Gender differences in blood pressure regulation following artificial gravity exposure

    Science.gov (United States)

    Evans, Joyce; Goswami, Nandu; Kostas, Vladimir; Zhang, Qingguang; Ferguson, Connor; Moore, Fritz; Stenger, Michael, , Dr; Serrador, Jorge; W, Siqi

    Introduction. Before countermeasures to space flight cardiovascular deconditioning are established, gender differences in cardiovascular responses to orthostatic stress, in general, and to orthostatic stress following exposure to artificial gravity (AG), in particular, need to be determined. Our recent determination that a short exposure to AG improved the orthostatic tolerance limit (OTL) of cardiovascularly deconditioned subjects drives the current effort to determine mechanisms of that improvement in men and in women. Methods. We determined the OTL of 9 men and 8 women following a 90 min exposure to AG compared to that following 90 min of head down bed rest (HDBR). On both days (21 days apart), subjects were made hypovolemic (low salt diet plus 20 mg intravenous furosemide) and orthostatic tolerance was determined from a combination of head up tilt and increasing lower body negative pressure until presyncope. Mean values and correlations with OTL were determined for heart rate, blood pressure, stroke volume, cardiac output, total peripheral resistance (Finometer), middle cerebral artery flow velocity (DWL), partial pressure of carbon dioxide (Novametrics) and body segmental impedance (UFI THRIM) at supine baseline, during orthostatic stress to presyncope and at supine recovery. Results. Orthostatic tolerance of these hypovolemic subjects was significantly greater following AG than following HDBR. Exposure to AG increased cardiac output in both men and women and increased stroke volume in women. In addition, AG decreased systolic blood pressure in men, but not women, and increased cerebral flow in women, but not men. In both men and women, AG exposure decreased peripheral resistance and decreased cerebrovascular resistance in women. Men’s heart rate rose more at the end of OTL on their AG, compared to their HDBR, day but women’s fell. Presyncopal stroke volume reached the same level on each day of study for both men and women. Conclusions. In the present

  6. Systolic Pressure in Different Percents of Stenosis at Major Arteries

    CERN Document Server

    Mirzaee, Mohammad Reza; Firoozabadi, Bahar; Dandaneband, Meitham

    2016-01-01

    - Modeling Human cardiovascular system is always an important issue. One of the most effective methods is using lumped model to reach to a complete model of human cardiovascular system. Such modeling with advanced considerations is used in this paper. Some of these considerations are as follow: Exact simulating of ventricles as pressure suppliers, peristaltic motion of descending arteries as additional suppliers, and dividing each vessel into more than one compartment to reach more accurate answers. Finally a circuit with more than 150 RLC segments and different elements is made. Then the verification of our complex circuit is done and at the end, obstruction as an important abnormality is investigated. For this aim different percents of obstruction in vital arteries are considered and the results are brought as different graphs at the end. According to physiological texts the citation of our simulation and its results are obvious. To earn productive information about arteries characteristics a 36-vessels mod...

  7. Different origins of garnet in high pressure to ultrahigh pressure metamorphic rocks

    Science.gov (United States)

    Xia, Qiong-Xia; Zhou, Li-Gang

    2017-09-01

    Garnet in high-pressure (HP) to ultrahigh-pressure (UHP) metamorphic rocks in subduction zone commonly shows considerable zonation in major and trace elements as well as mineral inclusions, which bears information on its growth mechanism via metamorphic or peritectic reactions in coexistence with relic minerals and metamorphic fluids or anatectic melts at subduction-zone conditions. It provides an important target to retrieve physicochemical changes in subduction-zone processes, including those not only in pressure and temperature but also in the durations of metamorphism and anatexis. Garnet from different compositions of HP to UHP metamorphic rocks may show different types of major and trace element zonation, as well as mineral inclusions. Discrimination between the different origins of garnet provides important constraints on pressure and temperature and the evolution history for the HP to UHP metamorphic rocks. Magmatic garnet may occur as relics in granitic gneisses despite metamorphic modification at subduction-zone conditions, with spessartine-increasing or flat major element profiles from inner to outer core and exceptionally higher contents of trace elements than metamorphic mantle and rim. Metamorphic garnet can grow at different metamorphic stages during prograde subduction and retrograde exhumation, with spessartine-decreasing from core to rim if the intracrystalline diffusion is not too fast. The compositional profiles of metamorphic garnet in the abundances of grossular, almandine and pyrope are variable depending on the composition of host rocks and co-existing minerals. Peritectic garnet grows through peritectic reactions during partial melting of HP to UHP rocks, with the composition of major elements to be controlled by anatectic P-T conditions and the compositions of parental rocks and anatectic melts. Trace element profiles in garnet with different origins are also variable depending on the coexisting mineral assemblages, the garnet

  8. Advanced Technologies for Monitoring CO2 Saturation and Pore Pressure in Geologic Formations: Linking the Chemical and Physical Effects to Elastic and Transport Properties

    Energy Technology Data Exchange (ETDEWEB)

    Mavko, G.; Vanorio, T.; Vialle, S.; Saxena, N.

    2014-03-31

    Ultrasonic P- and S-wave velocities were measured over a range of confining pressures while injecting CO2 and brine into the samples. Pore fluid pressure was also varied and monitored together with porosity during injection. Effective medium models were developed to understand the mechanisms and impact of observed changes and to provide the means for implementation of the interpretation methodologies in the field. Ultrasonic P- and S-wave velocities in carbonate rocks show as much as 20-50% decrease after injection of the reactive CO2-brine mixture; the changes were caused by permanent changes to the rock elastic frame associated with dissolution of mineral. Velocity decreases were observed under both dry and fluid-saturated conditions, and the amount of change was correlated with the initial pore fabrics. Scanning Electron Microscope images of carbonate rock microstructures were taken before and after injection of CO2-rich water. The images reveal enlargement of the pores, dissolution of micrite (micron-scale calcite crystals), and pitting of grain surfaces caused by the fluid- solid chemical reactivity. The magnitude of the changes correlates with the rock microtexture – tight, high surface area samples showed the largest changes in permeability and smallest changes in porosity and elastic stiffness compared to those in rocks with looser texture and larger intergranular pore space. Changes to the pore space also occurred from flow of fine particles with the injected fluid. Carbonates with grain-coating materials, such as residual oil, experienced very little permanent change during injection. In the tight micrite/spar cement component, dissolution is controlled by diffusion: the mass transfer of products and reactants is thus slow and the fluid is expected to be close to thermodynamical equilibrium with the calcite, leading to very little dissolution, or even precipitation. In the microporous rounded micrite and macropores, dissolution is controlled by

  9. Numerical investigation of saturated upward flow boiling of water in a vertical tube using VOF model: effect of different boundary conditions

    Science.gov (United States)

    Hasanpour, B.; Irandoost, M. S.; Hassani, M.; Kouhikamali, R.

    2018-01-01

    In this paper a numerical simulation of upward two-phase flow evaporation in a vertical tube has been studied by considering water as working fluid. To this end, the computational fluid dynamic simulations of this system are performed with heat and mass transfer mechanisms due to energy transfer during the phase change interaction near the heat transfer surface. The volume of fluid model in an available Eulerian-Eulerian approach based on finite volume method is utilized and the mass source term in conservation of mass equation is implemented using a user defined function. The characteristics of water flow boiling such as void fraction and heat transfer coefficient distribution are investigated. The main cause of fluctuations on heat transfer coefficient and volume fraction is velocity increment in the vapor phase rather than the liquid phase. The case study of this research including convective heat transfer coefficient and tube diameter are considered as a parametric study. The operating conditions are considered at high pressure in saturation temperature and the physical properties of water are determined by considering system's inlet temperature and pressure in saturation conditions. Good agreement is achieved between the numerical and the experimental values of heat transfer coefficients.

  10. Stochastic microstructural modeling of fuel cell gas diffusion layers and numerical determination of transport properties in different liquid water saturation levels

    Science.gov (United States)

    Tayarani-Yoosefabadi, Z.; Harvey, D.; Bellerive, J.; Kjeang, E.

    2016-01-01

    Gas diffusion layer (GDL) materials in polymer electrolyte membrane fuel cells (PEMFCs) are commonly made hydrophobic to enhance water management by avoiding liquid water blockage of the pores and facilitating reactant gas transport to the adjacent catalyst layer. In this work, a stochastic microstructural modeling approach is developed to simulate the transport properties of a commercial carbon paper based GDL under a range of PTFE loadings and liquid water saturation levels. The proposed novel stochastic method mimics the GDL manufacturing process steps and resolves all relevant phases including fiber, binder, PTFE, liquid water, and gas. After thorough validation of the general microstructure with literature and in-house data, a comprehensive set of anisotropic transport properties is simulated for the reconstructed GDL in different PTFE loadings and liquid water saturation levels and validated through a comparison with in-house ex situ experimental data and empirical formulations. In general, the results show good agreement between simulated and measured data. Decreasing trends in porosity, gas diffusivity, and permeability is obtained by increasing the PTFE loading and liquid water content, while the thermal conductivity is found to increase with liquid water saturation. Using the validated model, new correlations for saturation dependent GDL properties are proposed.

  11. Oscillometric blood pressure measurements: differences between measured and calculated mean arterial pressure.

    NARCIS (Netherlands)

    Kiers, H.D.; Hofstra, J.M.; Wetzels, J.F.M.

    2008-01-01

    Mean arterial pressure (MAP) is often used as an index of overall blood pressure. In recent years, the use of automated oscillometric blood pressure measurement devices is increasing. These devices directly measure and display MAP; however, MAP is often calculated from systolic blood pressure (SBP)

  12. Different Selection Pressures Give Rise to Distinct Ethnic Phenomena

    Science.gov (United States)

    Moya, Cristina; Boyd, Robert

    2015-01-01

    Many accounts of ethnic phenomena imply that processes such as stereotyping, essentialism, ethnocentrism, and intergroup hostility stem from a unitary adaptation for reasoning about groups. This is partly justified by the phenomena’s co-occurrence in correlational studies. Here we argue that these behaviors are better modeled as functionally independent adaptations that arose in response to different selection pressures throughout human evolution. As such, different mechanisms may be triggered by different group boundaries within a single society. We illustrate this functionalist framework using ethnographic work from the Quechua-Aymara language boundary in the Peruvian Altiplano. We show that different group boundaries motivate different ethnic phenomena. For example, people have strong stereotypes about socioeconomic categories, which are not cooperative units, whereas they hold fewer stereotypes about communities, which are the primary focus of cooperative activity. We also show that, despite the cross-cultural importance of ethnolinguistic boundaries, the Quechua-Aymara linguistic distinction does not strongly motivate any of these intergroup processes. PMID:25731969

  13. Saturation Transfer Difference NMR as an Analytical Tool for Detection and Differentiation of Plastic Explosives on the Basis of Minor Plasticizer Composition

    Science.gov (United States)

    2015-05-01

    HMX); ethylene glycol dinitrate (EGDN); ammonium nitrate (AN); and nitrocellulose (NC).1–4 Alternatively, in one recent study,5 fluorescence-based...green) plastic explosive mixtures. Top trace (red) represents the 1D 1H NMR for all plasticizers present together in the NMR sample (1.0 mM concentration ...saturation transfer difference AN ammonium nitrate BSA bovine serum albumin EGDN ethylene glycol dinitrate HDO partially deuterated water HMX

  14. Blood pressure variations in Subjects with different Haemoglobin ...

    African Journals Online (AJOL)

    Previous studies on low blood pressure in patients with homozygous sickle cell disease (SCD) have sought various hypotheses on the mechanism of their low blood pressure. However, these studies have not compared the role of the single inheritance of the s-gene in the variations in blood pressures as well as relating the ...

  15. Hydraulic High Pressure Valve Controller Using the In-Situ Pressure Difference

    Science.gov (United States)

    Bao, Xiaoqi (Inventor); Sherrit, Stewart (Inventor); Badescu, Mircea (Inventor); Bar-Cohen, Yoseph (Inventor); Hall, Jeffery L. (Inventor)

    2016-01-01

    A hydraulic valve controller that uses an existing pressure differential as some or all of the power source for valve operation. In a high pressure environment, such as downhole in an oil or gas well, the pressure differential between the inside of a pipe and the outside of the pipe may be adequately large to drive a linear slide valve. The valve is operated hydraulically by a piston in a bore. When a higher pressure is applied to one end of the bore and a lower pressure to the other end, the piston moves in response to the pressure differential and drives a valve attached to it. If the pressure differential is too small to drive the piston at a sufficiently high speed, a pump is provided to generate a larger pressure differential to be applied. The apparatus is conveniently constructed using multiport valves, which can be rotary valves.

  16. ANALYSIS OF DIFFERENCES IN BLOOD PRESSURE OF WOMEN BELONGING TO DIFFERENT AGE GROUPS.

    Science.gov (United States)

    Škrkar, Stanislav; Mikalački, Milena; Čokorilo, Nebojša; Erić, Mirela

    2015-01-01

    One of the risk factors for the occurrence of arteriosclerosis and coronary heart diseases is physical inactivity. Together with hypokinesia, excessive feeding, age and other factors, make a multifactorial cause of cardiovascular disease. Positive effects of physical activities have been proved in the primary, secondary and tertiary prevention of coronary heart diseases. This study included 119 women from 20 to 76 years of age. All subjects vere nonsmokers who did not have a cardiovascular disease, and were divided into five different age groups. Systolic and diastolic blood pressure was measured by the digital blood pressure measuring device with cuff OMRON M4-1. The evaluation of blood pressure was performed at the Faculty of Sport and Physical Education in Novi Sad. The data processing was done by the statistical package SPSS 20.0. According to the obtained data it can be concluded that there are statistically significant differences in both individual and general system of the observed variables in different age groups. In addition, there are statistically significant differences between pairs of groups, which were observed when comparing with the oldest age group. The programmes of prevention and control of cardiovascular diseases should decrease the influence of risk factors and improve diagnostics and therapy of cardiovascular diseases.

  17. The distribution of saturated clusters in wetted granular materials

    Science.gov (United States)

    Li, Shuoqi; Hanaor, Dorian; Gan, Yixiang

    2017-06-01

    The hydro-mechanical behaviour of partially saturated granular materials is greatly influenced by the spatial and temporal distribution of liquid within the media. The aim of this paper is to characterise the distribution of saturated clusters in granular materials using an optical imaging method under different water drainage conditions. A saturated cluster is formed when a liquid phase fully occupies the pore space between solid grains in a localized region. The samples considered here were prepared by vibrating mono-sized glass beads to form closely packed assemblies in a rectangular container. A range of drainage conditions were applied to the specimen by tilting the container and employing different flow rates, and the liquid pressure was recorded at different positions in the experimental cell. The formation of saturated clusters during the liquid withdrawal processes is governed by three competing mechanisms arising from viscous, capillary, and gravitational forces. When the flow rate is sufficiently large and the gravity component is sufficiently small, the viscous force tends to destabilize the liquid front leading to the formation of narrow fingers of saturated material. As the water channels along these liquid fingers break, saturated clusters are formed inside the specimen. Subsequently, a spatial and temporal distribution of saturated clusters can be observed. We investigated the resulting saturated cluster distribution as a function of flow rate and gravity to achieve a fundamental understanding of the formation and evolution of such clusters in partially saturated granular materials. This study serves as a bridge between pore-scale behavior and the overall hydro-mechanical characteristics in partially saturated soils.

  18. Interaction of central and peripheral factors during repeated sprints at different levels of arterial O2 saturation.

    Directory of Open Access Journals (Sweden)

    François Billaut

    Full Text Available PURPOSE: To investigate the interaction between the development of peripheral locomotor muscle fatigue, muscle recruitment and performance during repeated-sprint exercise (RSE. METHOD: In a single-blind, randomised and cross-over design, ten male team-sport athletes performed two RSE (fifteen 5-s cycling sprints interspersed with 25 s of rest; power self-selected in normoxia and in acute moderate hypoxia (FIO2 0.138. Mechanical work, total electromyographic intensity (summed quadriceps electromyograms, RMSsum and muscle (vastus lateralis and pre-fontal cortex near-infrared spectroscopy (NIRS parameters were calculated for every sprint. Blood lactate concentration ([Lac(-] was measured throughout the protocol. Peripheral quadriceps fatigue was assessed via changes in potentiated quadriceps twitch force (ΔQtw,pot pre- versus post-exercise in response to supra-maximal magnetic femoral nerve stimulation. The central activation ratio (QCAR was used to quantify completeness of quadriceps activation. RESULTS: Compared with normoxia, hypoxia reduced arterial oxygen saturation (-13.7%, P=0.001, quadriceps RMSsum (-13.7%, P=0.022, QCAR (-3.3%, P=0.041 and total mechanical work (-8.3%, P=0.019. However, the magnitude of quadriceps fatigue induced by RSE was similar in the two conditions (ΔQtw,pot: -53.5% and -55.1%, P=0.71. The lower cycling performance in hypoxia occurred despite similar metabolic (muscle NIRS parameters and blood [Lac(-] and functional (twitch and M-wave muscle states. CONCLUSION: Results suggest that the central nervous system regulates quadriceps muscle recruitment and, thereby, performance to limit the development of muscle fatigue during intermittent, short sprints. This finding highlights the complex interaction between muscular perturbations and neural adjustments during sprint exercise, and further supports the presence of pacing during intermittent sprint exercise.

  19. Genes influencing circadian differences in blood pressure in hypertensive mice.

    Directory of Open Access Journals (Sweden)

    Francine Z Marques

    Full Text Available Essential hypertension is a common multifactorial heritable condition in which increased sympathetic outflow from the central nervous system is involved in the elevation in blood pressure (BP, as well as the exaggerated morning surge in BP that is a risk factor for myocardial infarction and stroke in hypertensive patients. The Schlager BPH/2J mouse is a genetic model of hypertension in which increased sympathetic outflow from the hypothalamus has an important etiological role in the elevation of BP. Schlager hypertensive mice exhibit a large variation in BP between the active and inactive periods of the day, and also show a morning surge in BP. To investigate the genes responsible for the circadian variation in BP in hypertension, hypothalamic tissue was collected from BPH/2J and normotensive BPN/3J mice at the 'peak' (n = 12 and 'trough' (n = 6 of diurnal BP. Using Affymetrix GeneChip® Mouse Gene 1.0 ST Arrays, validation by quantitative real-time PCR and a statistical method that adjusted for clock genes, we identified 212 hypothalamic genes whose expression differed between 'peak' and 'trough' BP in the hypertensive strain. These included genes with known roles in BP regulation, such as vasopressin, oxytocin and thyrotropin releasing hormone, as well as genes not recognized previously as regulators of BP, including chemokine (C-C motif ligand 19, hypocretin and zinc finger and BTB domain containing 16. Gene ontology analysis showed an enrichment of terms for inflammatory response, mitochondrial proton-transporting ATP synthase complex, structural constituent of ribosome, amongst others. In conclusion, we have identified genes whose expression differs between the peak and trough of 24-hour circadian BP in BPH/2J mice, pointing to mechanisms responsible for diurnal variation in BP. The findings may assist in the elucidation of the mechanism for the morning surge in BP in essential hypertension.

  20. [Study of blood oxygen saturation, heart rate changes and plateau reaction of the Antarctic Kunlun station investigation team in different plateau environments].

    Science.gov (United States)

    Zhao, Shun-yun; Wu, Xin-min; Guo, Ya-min; Zhang, Shu-shun; An, Yan-ming; Li, Bing; Wang, Hao

    2013-06-11

    To explore the blood oxygen saturation and heart rate changes of the Antarctic explorers. During August 2010 to April 2011, the changes in blood oxygen saturation, heart rate and plateau reaction of 16 Antarctic expedition team in different plateau environments (Tibetan plateau versus Antarctic plateau) were monitored with the noninvasive pulse oximeter MD300-C. The extent of acute mountain sickness was determined according to the Lake Louise Consensus acute mountain reaction symptom scores and judgment method. The changes of blood oxygen saturation, heart rate at different altitudes of 110, 3650, 4300 m (96.8% ± 1.2%,89.1% ± 1.2%, 86.1% ± 2.0%, (75.0 ± 5.4) times/min, (104.0 ± 4.3) times/min, (113.0 ± 5.2) times/min,F = 214.155, 240.088,both P rate at different altitudes of 2000, 2500, 3000, 3500 and 4087 m(91.9% ± 1.3%,90.5% ± 1.3%,87.6% ± 1.4%,85.0% ± 1.8%,81.5% ± 2.2%, (85.9 ± 3.2) times/min, (90.6 ± 2.8) times/min, (97.8 ± 4.1) times/min, (102.0 ± 3.4) times/min, (106.3 ± 3.9) times/min, F = 105.418, 90.174, both P rate were both correlated with the risk of altitude sickness (r = -0.446 and 0.565, both P rate of the Antarctic explorers. And with the increases of altitude, the risk of altitude sickness gradually increases.

  1. Numerical solution for 5-layer laminate technique to determine saturation solubility of a drug in a thin film of pressure sensitive adhesive.

    Science.gov (United States)

    Bänsch, Eberhard; Reismann, Simone; Lee, Geoffrey

    2014-08-01

    A numerical solution of the one-dimensional diffusion equation is presented to describe the 5-layer laminate technique for estimating the saturation solubility of a drug in a thin polymer film. The boundary and initial conditions encompass a donor layer, a separating membrane, and an acceptor layer. Alteration of the drug's partition coefficient between donor and separating membrane has little influence on drug accumulation with the acceptor. The diffusivity in the separating membrane should be high to promote a short experimental time to achieve saturation equilibrium in the acceptor layer. The essential parameter to give rapid equilibrium is the thickness of the acceptor polymer film. For values of diffusivity typical for drugs of molecular weight around 500 an acceptor layer thickness of 10 µm-20 µm is required to achieve equilibrium within less than 10 d. These simulations allow the selection of suitable experimental conditions to make the 5-layer laminate technique a viable method for routine use.

  2. Chronic administration of saturated fats and fructose differently affect SREBP activity resulting in different modulation of Nrf2 and Nlrp3 inflammasome pathways in mice liver.

    Science.gov (United States)

    Nigro, Debora; Menotti, Francesca; Cento, Alessia S; Serpe, Loredana; Chiazza, Fausto; Dal Bello, Federica; Romaniello, Francesco; Medana, Claudio; Collino, Massimo; Aragno, Manuela; Mastrocola, Raffaella

    2017-04-01

    The overconsumption of both saturated fats and fructose in the modern society has been related to the development of nonalcoholic fatty liver disease (NAFLD). However, the specific contribution of individual dietary components on the progression of NAFLD to nonalcoholic steatohepatitis (NASH) has been poorly investigated. Therefore, the aim of our study was to investigate the dissimilar effects of these two dietary components on selected proinflammatory and antioxidant pathways in the liver of C57BL/6 mice fed a standard (SD), a 45% saturated fat (HFAT) or a 60% fructose (HFRT) diet for 12 weeks. HFAT diet evoked systemic metabolic alterations and overweight, not observed in HFRT mice. However, HFRT mice had a greater hepatic triglyceride deposition with increased ratio of triacylglycerols containing the palmitic acid compared to HFAT, as assessed by liquid chromatography-mass spectrometry analysis. This effect is due to the higher activation of the SCAP/SREBP1c lipogenic pathway by HFRT feeding. In addition, we found inhibition of Keap1/Nrf2 antioxidant signaling and more robust stimulation of the Nlrp3 inflammasome pathway in the livers of HFRT-fed mice when compared with HFAT-fed mice, which is consistent with the recent finding that palmitate and SREBP1c are implicated in hepatic oxidative stress and inflammation. These effects were associated with increased hepatic inflammation, as confirmed by high expression of markers of leukocyte infiltration in the HFRT group. Thus, we hypothesize an amplifying loop among lipogenesis, palmitate, Nrf2 and Nlrp3 that leads to a higher risk of NAFLD progression to NASH in a high-fructose diet compared to a high-saturated fat intake. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Association between minor loading vein architecture and light- and CO2-saturated rates of photosynthetic oxygen evolution among Arabidopsis thaliana ecotypes from different latitudes

    Directory of Open Access Journals (Sweden)

    Christopher M Cohu

    2013-07-01

    Full Text Available Through microscopic analysis of veins and assessment of light- and CO2-saturated rates of photosynthetic oxygen evolution, we investigated the relationship between minor loading vein anatomy and photosynthesis of mature leaves in three ecotypes of Arabidopsis thaliana grown under four different combinations of temperature and photon flux density (PFD. All three ecotypes exhibited greater numbers and cross-sectional area of phloem cells as well as higher photosynthesis rates in response to higher PFD and especially lower temperature. The Swedish ecotype exhibited the strongest response to these conditions, the Italian ecotype the weakest response, and the Col-0 ecotype exhibited an intermediate response. Among all three ecotypes, strong linear relationships were found between light- and CO2-saturated rates of photosynthetic oxygen evolution and the number and area of either sieve elements or of companion and phloem parenchyma cells in foliar minor loading veins, with the Swedish ecotype showing the highest number of cells in minor loading veins (and largest minor veins coupled with unprecedented high rates of photosynthesis. Linear, albeit less significant, relationships were also observed between number and cross-sectional area of tracheids per minor loading vein versus light- and CO2-saturated rates of photosynthetic oxygen evolution. We suggest that sugar distribution infrastructure in the phloem is co-regulated with other features that set the upper limit for photosynthesis. The apparent genetic differences among Arabidopsis ecotypes should allow for future identification of the gene(s involved in augmenting sugar-loading and -transporting phloem cells and maximal rates of photosynthesis.

  4. The differences in crown formation during the splash on the thin water layers formed on the saturated soil surface and model surface

    Science.gov (United States)

    Mazur, Rafał; Polakowski, Cezary; Bieganowski, Andrzej

    2017-01-01

    Splash is the first stage of a negative phenomenon–soil erosion. The aim of this work was to describe the crown formation quantitatively (as part of the splash erosion) and compare the course of this phenomenon on the thin water film formed on a smooth glass surface and on the surface of saturated soil. The height of the falling water drop was 1.5 m. The observation of the crowns was carried out by high-speed cameras. The static and dynamic parameters of crown formation were analysed. It was found that the crowns formed on the water film covering the saturated soil surface were smaller and the time intervals of their existence were shorter. In addition, the shapes of the crowns were different from those created on the water layer covering the glass surface. These differences can be explained by the slightly different values of surface tension and viscosity of the soil solution, the greater roughness of the soil surface and the lower thickness of the water film on the soil surface. PMID:28750072

  5. Facts about saturated fats

    Science.gov (United States)

    ... fat diary with low-fat or nonfat milk, yogurt, and cheese. Eat more fruits, vegetables, whole grains, and other foods with low or no saturated fat. Alternative Names Cholesterol - saturated fat; Atherosclerosis - saturated fat; Hardening of the ...

  6. Saturated fat (image)

    Science.gov (United States)

    Saturated fat can raise blood cholesterol and can put you at risk for heart disease and stroke. You should ... limit any foods that are high in saturated fat. Sources of saturated fat include whole-milk dairy ...

  7. Automatic blood pressure measurement: the oscillometric waveform shape is a potential contributor to differences between oscillometric and auscultatory pressure measurements.

    Science.gov (United States)

    Amoore, John N; Lemesre, Yann; Murray, Ian C; Mieke, Stephan; King, Susan T; Smith, Fiona E; Murray, Alan

    2008-01-01

    To explore the differences between oscillometric and auscultatory measurements. From a simulator evaluation of a non-invasive blood pressure (NIBP) device regenerating 242 oscillometric blood pressure waveforms from 124 subjects, 10 waveforms were selected based on the differences between the NIBP (oscillometric) and auscultatory pressure measurements. Two waveforms were selected for each of five criteria: systolic over and underestimation; diastolic over and underestimation; and close agreement for both systolic and diastolic pressures. The 10 waveforms were presented to seven different devices and the oscillometric-auscultatory pressure differences were compared between devices and with the oscillometric waveform shapes. Consistent patterns of waveform-dependent over and underestimation of systolic and diastolic pressures were shown for all seven devices. The mean and standard deviation, for all devices, of oscillometric-auscultatory pressure differences were: for the systolic overestimated waveforms, 36 +/- 28/-6 +/- 3 and 23 +/- 2/-1 +/- 3 mmHg (systolic/diastolic differences); for systolic underestimated waveforms, -21 +/- 5/-4 +/- 3 and -11 +/- 4/-3 +/- 3 mmHg; for diastolic overestimated waveforms, 3 +/- 4/12 +/- 5 and 17 +/- 6/10 +/- 2 mmHg; for diastolic underestimated waveforms, 1 +/- 4/-22 +/- 4 and -9 +/- 6/-29 +/- 4 mmHg; and for the two waveforms with good agreement, 0 +/- 6/0 +/- 3 and -2 +/- 4/-4 +/- 3 mmHg. Waveforms for which devices showed good oscillometric and auscultatory agreement had smooth envelopes with clearly defined peaks, compared with the broader plateau and complex shapes of those waveforms for which devices over or underestimated pressures. By increasing the understanding of the characteristics and limitations of the oscillometric method and the effects of waveform shape on pressure measurements, simulator evaluation should lead to improvements in NIBP devices.

  8. Pressure transmission area and maximum pressure transmission of different thermoplastic resin denture base materials under impact load.

    Science.gov (United States)

    Nasution, Hubban; Kamonkhantikul, Krid; Arksornnukit, Mansuang; Takahashi, Hidekazu

    2017-06-09

    The purposes of the present study were to examine the pressure transmission area and maximum pressure transmission of thermoplastic resin denture base materials under an impact load, and to evaluate the modulus of elasticity and nanohardness of thermoplastic resin denture base. Three injection-molded thermoplastic resin denture base materials [polycarbonate (Basis PC), ethylene propylene (Duraflex), and polyamide (Valplast)] and one conventional heat-polymerized acrylic resin (PMMA, SR Triplex Hot) denture base, all with a mandibular first molar acrylic resin denture tooth set in were evaluated (n=6). Pressure transmission area and maximum pressure transmission of the specimens under an impact load were observed by using pressure-sensitive sheets. The modulus of elasticity and nanohardness of each denture base (n=10) were measured on 15×15×15×3mm(3) specimen by using an ultramicroindentation system. The pressure transmission area, modulus of elasticity, and nanohardness data were statistically analyzed with 1-way ANOVA, followed by Tamhane or Tukey HSD post hoc test (α=.05). The maximum pressure transmission data were statistically analyzed with Kruskal-Wallis H test, followed by Mann-Whitney U test (α=.05). Polymethyl methacrylate showed significantly larger pressure transmission area and higher maximum pressure transmission than the other groups (P<.001). Significant differences were found in modulus of elasticity and nanohardness among the four types of denture bases (P<.001). Pressure transmission area and maximum pressure transmission varied among the thermoplastic resin denture base materials. Differences in the modulus of elasticity and nanohardness of each type of denture base were demonstrated. Copyright © 2017 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  9. Conductividad hidráulica en un suelo aluvial en respuesta al porcentaje de sodio intercambiable Saturated hydraulic conductivity of an alluvial soil with different exchangeable sodium percentages

    Directory of Open Access Journals (Sweden)

    Francisco L. Barreto Filho

    2003-08-01

    Full Text Available El efecto del porcentaje de sodio intercambiable (PSI sobre la conductividad hidráulica de un suelo saturado, fue estudiado en condiciones de laboratorio a través de la determinación de las relaciones entre la conductividad hidráulica medida en un suelo normal y las medidas en suelos con diferentes PSI. Los resultados muestran una gran reducción de la conductividad hidráulica con el aumento de sodio en el suelo, llegando esta reducción a ser en las muestras más sodificadas de casi 100%, cuando comparadas con las muestras sin sodio, hecho probablemente acontecido debido al efecto dispersante del sodio sobre las partículas del suelo.The effect of different exchangeable sodium percentages (ESP on the saturated hydraulic conductivity of a soil was studied under laboratory conditions by determining the relationship between the hydraulic conductivity of a normal soil and that measured on soil with different ESP. The results show a great reduction in the saturated hydraulic conductivity with the increase of the exchangeable sodium percentage in the soil, this reduction being as great as 100% on the highly sodified samples when compared with those which did not receive sodium treatment. This fact is explained due to the dispersing effect of the exchangeable sodium on the soil particles.

  10. Determination of saturation functions and wettability for chalk based on measured fluid saturations

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, D.; Bech, N.; Moeller Nielsen, C.

    1998-08-01

    The end effect of displacement experiments on low permeable porous media is used for determination of relative permeability functions and capillary pressure functions. Saturation functions for a drainage process are determined from a primary drainage experiment. A reversal of the flooding direction creates an intrinsic imbibition process in the sample, which enables determination if imbibition saturation functions. The saturation functions are determined by a parameter estimation technique. Scanning effects are modelled by the method of Killough. Saturation profiles are determined by NMR. (au)

  11. Detection of deuterium retention by LIBS at different background pressures

    Science.gov (United States)

    Paris, P.; Butikova, J.; Laan, M.; Aints, M.; Hakola, A.; Piip, K.; Tufail, I.; Veis, P.

    2017-01-01

    ITER plans foresee the quantitative diagnostics of fuel retention in reactor walls at near-atmospheric pressures. Using laser induced breakdown spectroscopy (LIBS) for this purpose assumes a reliable resolving of Balmer α-lines of hydrogen isotopes in spectra of plasma produced by focused laser radiation onto the target surface. To develop LIBS for quantitative diagnostics of fuel retention during the maintenance breaks of ITER, the effect of background gas pressure on the laser-induced plasma characteristics has been studied. The background pressure limits the expansion rate of plasma and as a result it leads to higher plasma concentrations. At the same time the limiting factor of the resolving of hydrogen isotope lines is the lines broadening by Stark effect, which is the function of electron concentration. The resolving of lines become possible recording spectra at longer delay times after the laser pulse. On the other hand, at longer delays the signal-to-noise ratio decreases. As a compromise, we found that at atmospheric pressure and at delay times >2000 ns, a fitting of H α and D α lines by Voigt contours allows a reliable discrimination of these lines.

  12. Energy Transfer in Mixed Convection MHD Flow of Nanofluid Containing Different Shapes of Nanoparticles in a Channel Filled with Saturated Porous Medium.

    Science.gov (United States)

    Aaiza, Gul; Khan, Ilyas; Shafie, Sharidan

    2015-12-01

    Energy transfer in mixed convection unsteady magnetohydrodynamic (MHD) flow of an incompressible nanofluid inside a channel filled with saturated porous medium is investigated. The channel with non-uniform walls temperature is taken in a vertical direction under the influence of a transverse magnetic field. Based on the physical boundary conditions, three different flow situations are discussed. The problem is modelled in terms of partial differential equations with physical boundary conditions. Four different shapes of nanoparticles of equal volume fraction are used in conventional base fluids, ethylene glycol (EG) (C 2 H 6 O 2 ) and water (H 2 O). Solutions for velocity and temperature are obtained discussed graphically in various plots. It is found that viscosity and thermal conductivity are the most prominent parameters responsible for different results of velocity and temperature. Due to higher viscosity and thermal conductivity, C 2 H 6 O 2 is regarded as better convectional base fluid compared to H 2 O.

  13. Elastic velocities of partially gas-saturated unconsolidated sediments

    Science.gov (United States)

    Lee, M.W.

    2004-01-01

    Fluid in sediments significantly affects elastic properties of sediments and gas in the pore space can be identified by a marked reduction of P-wave velocity or a decrease of Poisson's ratio. The elastic properties of gas-saturated sediments can be predicted by the classical Biot-Gassmann theory (BGT). However, parameters for the BGT such as the Biot coefficient or moduli of dry frame of unconsolidated and high porosity sediments are not readily available. Dependence of velocities on differential pressure or porosity for partially gas-saturated sediments is formulated using properties derived from velocities of water-saturated sediments. Laboratory samples for unconsolidated and consolidated sediments and well log data acquired for unconsolidated marine sediments agree well with the predictions. However, because the P-wave velocity depends highly on how the gas is saturated in the pore space such as uniform or patch, the amounts of gas estimated from the P-wave velocity contains high uncertainty. The modeled Vp/Vs ratio of partially gas-saturated sediment using the patch distribution is usually greater than 1.6, whereas the ratio modeled assuming a uniform distribution is about 1.6. Thus, Poisson's ratio or Vp/Vs ratio may be used to differentiate patch from uniform saturation, but differences between various models of patch saturation cannot be easily identified. ?? 2004 Elsevier Ltd. All rights reserved.

  14. Energy resolution and power consumption of Timepix detector for different detector settings and saturation of front-end electronics

    Science.gov (United States)

    Kroupa, M.; Hoang, S.; Stoffle, N.; Soukup, P.; Jakubek, J.; Pinsky, L. S.

    2014-05-01

    An ongoing research project in the area of radiation monitoring employing the Timepix technology from the CERN-based Medipix2 Collaboration profits greatly from optimizing the precision of the position and energy information obtained for the detected quanta. Wider applications of the Timepix technology as a radiation monitor also puts new demands on the precision and speed of the energy calibration. We compare the analog signal in pixel front-end electronics for different sources used during detector evaluation and energy calibration. We use the direct measurement of the analog signal from the pixel preamplifier and comparator to characterize pulse shape differences for different sources, e.g. internal test pulses, external test pulses, ionizing radiation, etc. and study their interchangeability. Accurate per-pixel energy calibration of the Timepix detector enables the direct measurement of the energy deposited by different types of ionizing radiation. The energy calibration process requires the application of a known charge to front-end electronics of each pixel. The small pixel size limits use of the radioactive sources. The 59.54 keV line from 241Am is commonly used as the highest point in calibration curve. The heavy ion dosimetry as encountered in the space radiation environment requires a considerable extrapolation to the energies in the MeV range. We have observed that for energies around and beyond 1 MeV the response of the Timepix's front-end electronics no longer follows the extrapolated calibration function. We have investigated this non-linearity and identified its source. We also propose both hardware and software solutions to suppress this effect. In this paper we show the impact on pixel calibration and the subsequent energy resolution for different detector settings as well as the resulting power consumptions. We discuss the parameter optimization for several different real-world applications.

  15. Droplet spectrum at different vapour pressure deficits1

    Directory of Open Access Journals (Sweden)

    Christiam Felipe Silva Maciel

    Full Text Available ABSTRACT An efficient pesticides spraying depends a lot in psychrometric conditions, mainly if it is using fine droplets, once climatic conditions may cause droplets evaporation and consequent financial loss to the farmer. Thus, the aim of this work was to determine the droplet spectrum depending on the vapour pressure deficits. The work was carried out inside of a climate chamber to obtain the vapour pressure deficits (VPDair. The laser particle analyzer, model Spraytech, was used to determine the droplet spectrum, and the experiment was conducted in factorial scheme 5 x 20, consisted of five working pressures (100; 200; 300; 400 and 500 kPa and twenty VPDair (2.3; 3.2; 4.2; 5.6; 7.0; 7.4; 9.5; 11.7; 12.7; 15.8; 16.4; 16.9; 21.2; 22.1; 22.2; 28.1; 29.7; 36.9 39.4 e 51.6 hPa, in completely randomized design with five replications. There is influence of VPDair on droplet spectrum behavior. Increasing the VPDair reduces the percentage of sprayed volume comprised by droplets with diameter between 100 and 200 µm, between 200 and 300 µm, between 300 and 400 µm, between 400 and 500 µm and between 500 and 600 µm. Increasing VPDair increases the VMD, Dv90, SPAN and the percentage of sprayed volume comprised by droplets larger than 600 µm.

  16. Evolution effects of the copper surface morphology on the nucleation density and growth of graphene domains at different growth pressures

    Energy Technology Data Exchange (ETDEWEB)

    Hedayat, Seyed Mahdi [Transport Phenomena & Nanotechnology Lab., School of Chemical Engineering, College of Engineering, University of Tehran (Iran, Islamic Republic of); Karimi-Sabet, Javad, E-mail: j_karimi@alum.sharif.edu [NFCRS, Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of); Shariaty-Niassar, Mojtaba, E-mail: mshariat@ut.ac.ir [Transport Phenomena & Nanotechnology Lab., School of Chemical Engineering, College of Engineering, University of Tehran (Iran, Islamic Republic of)

    2017-03-31

    Highlights: • Manipulation of the Cu surface morphology in a wide range by electropolishing treatment. • Comparison of the nucleation density of graphene at low pressure and atmospheric pressure CVD processes. • Controlling the evolution of the Cu surface morphology inside a novel confined space. • Growth of large-size graphene domains. - Abstract: In this work, we study the influence of the surface morphology of the catalytic copper substrate on the nucleation density and the growth rate of graphene domains at low and atmospheric pressure chemical vapor deposition (LPCVD and APCVD) processes. In order to obtain a wide range of initial surface morphology, precisely controlled electropolishing methods were developed to manipulate the roughntreess value of the as-received Cu substrate (RMS = 30 nm) to ultra-rough (RMS = 130 nm) and ultra-smooth (RMS = 2 nm) surfaces. The nucleation and growth of graphene domains show obviously different trends at LPCVD and APCVD conditions. In contrast to APCVD condition, the nucleation density of graphene domains is almost equal in substrates with different initial roughness values at LPCVD condition. We show that this is due to the evolution of the surface morphology of the Cu substrate during the graphene growth steps. By stopping the surface sublimation of copper substrate in a confined space saturated with Cu atoms, the evolution of the Cu surface was impeded. This results in the reduction of the nucleation density of graphene domains up to 24 times in the pre-smoothed Cu substrates at LPCVD condition.

  17. A Finite Difference Scheme for Double-Diffusive Unsteady Free Convection from a Curved Surface to a Saturated Porous Medium with a Non-Newtonian Fluid

    KAUST Repository

    El-Amin, Mohamed

    2011-05-14

    In this paper, a finite difference scheme is developed to solve the unsteady problem of combined heat and mass transfer from an isothermal curved surface to a porous medium saturated by a non-Newtonian fluid. The curved surface is kept at constant temperature and the power-law model is used to model the non-Newtonian fluid. The explicit finite difference method is used to solve simultaneously the equations of momentum, energy and concentration. The consistency of the explicit scheme is examined and the stability conditions are determined for each equation. Boundary layer and Boussinesq approximations have been incorporated. Numerical calculations are carried out for the various parameters entering into the problem. Velocity, temperature and concentration profiles are shown graphically. It is found that as time approaches infinity, the values of wall shear, heat transfer coefficient and concentration gradient at the wall, which are entered in tables, approach the steady state values.

  18. SOLUBILITIES AND PHYSICAL PROPERTIES OF SATURATED SOLUTIONS IN THE COPPER SULFATE + SULFURIC ACID + SEAWATER SYSTEM AT DIFFERENT TEMPERATURES

    OpenAIRE

    Justel,F. J.; Claros, M.; Taboada, M. E.

    2015-01-01

    Abstract In Chile, the most important economic activity is mining, concentrated in the north of the country. This is a desert region with limited water resources; therefore, the mining sector requires research and identification of alternative sources of water. One alternative is seawater, which can be a substitute of the limited fresh water resources in the region. This work determines the influence of seawater on the solid-liquid equilibrium for acid solutions of copper sulfate at different...

  19. A demonstration experiment for studying the properties of saturated vapor

    Science.gov (United States)

    Grebenev, Igor V.; Lebedeva, Olga V.; Polushkina, Svetlana V.

    2017-11-01

    The paper proposes an important demonstration experiment that can be used at secondary schools in physics. The described experiment helps students learn the main concepts of the topic ‘saturated vapor’, namely, evaporation, condensation, dynamic equilibrium, saturation vapor, partial pressure, and the dependence of saturated vapor pressure on temperature.

  20. New high pressure experiments on sulfide saturation of high-FeO∗ basalts with variable TiO2 contents - Implications for the sulfur inventory of the lunar interior

    Science.gov (United States)

    Ding, Shuo; Hough, Taylor; Dasgupta, Rajdeep

    2018-02-01

    In order to constrain sulfur concentration in intermediate to high-Ti mare basalts at sulfide saturation (SCSS), we experimentally equilibrated FeS melt and basaltic melt using a piston cylinder at 1.0-2.5 GPa and 1400-1600 °C, with two silicate compositions similar to high-Ti (Apollo 11: A11, ∼11.1 wt.% TiO2, 19.1 wt.% FeO∗, and 39.6 wt.% SiO2) and intermediate-Ti (Luna 16, ∼5 wt.% TiO2, 18.7 wt.% FeO∗, and 43.8 wt.% SiO2) mare basalts. Our experimental results show that SCSS increases with increasing temperature, and decreases with increasing pressure, which are similar to the results from previous experimental studies. SCSS in the A11 melt is systematically higher than that in the Luna 16 melt, which is likely due to higher FeO∗, and lower SiO2 and Al2O3 concentration in the former. Compared to the previously constructed SCSS models, including those designed for high-FeO∗ basalts, the SCSS values determined in this study are generally lower than the predicted values, with overprediction increasing with increasing melt TiO2 content. We attribute this to the lower SiO2 and Al2O3 concentration of the lunar magmas, which is beyond the calibration range of previous SCSS models, and also more abundant FeTiO3 complexes in our experimental melts that have higher TiO2 contents than previous models' calibration range. The formation of FeTiO3 complexes lowers the activity of FeO∗, a FeO∗silicatemelt, and therefore causes SCSS to decrease. To accommodate the unique lunar compositions, we have fitted a new SCSS model for basaltic melts of >5 wt.% FeO∗ and variable TiO2 contents. Using previous chalcophile element partitioning experiments that contained more complex Fe-Ni-S sulfide melts, we also derived an empirical correction that allows SCSS calculation for basalts where the equilibrium sulfides contain variable Ni contents of 10-50 wt.%. At the pressures and temperatures of multiple saturation points, SCSS of lunar magmas with compositions from picritic

  1. SOLUBILITIES AND PHYSICAL PROPERTIES OF SATURATED SOLUTIONS IN THE COPPER SULFATE + SULFURIC ACID + SEAWATER SYSTEM AT DIFFERENT TEMPERATURES

    Directory of Open Access Journals (Sweden)

    F. J. Justel

    2015-09-01

    Full Text Available AbstractIn Chile, the most important economic activity is mining, concentrated in the north of the country. This is a desert region with limited water resources; therefore, the mining sector requires research and identification of alternative sources of water. One alternative is seawater, which can be a substitute of the limited fresh water resources in the region. This work determines the influence of seawater on the solid-liquid equilibrium for acid solutions of copper sulfate at different temperatures (293.15 to 318.15 K, and its effect on physical properties (density, viscosity, and solubility. Knowledge of these properties and solubility data are useful in the leaching process and in the design of copper sulfate pentahydrate crystallization plants from the leaching process using seawater by means of the addition of sulfuric acid.

  2. Reference values of regional cerebral oxygen saturation during the first 3 days of life in preterm neonates

    NARCIS (Netherlands)

    Alderliesten, Thomas; Dix, Laura; Baerts, Wim; Caicedo, Alexander; van Huffel, Sabine; Naulaers, Gunnar; Groenendaal, Floris; van Bel, Frank; Lemmers, Petra

    2016-01-01

    Background:Currently, reliable reference values of regional cerebral oxygen saturation (rScO2) for different gestational age (GA) groups are lacking, which hampers the implementation of near-infrared spectroscopy (NIRS) alongside monitoring arterial oxygen saturation (SaO 2) and blood pressure in

  3. Generational Differences in Resistance to Peer Pressure among Mexican-Origin Adolescents.

    Science.gov (United States)

    Umana-Taylor, Adriana J.; Bamaca-Gomez, Mayra Y.

    2003-01-01

    Examined whether Mexican origin adolescents who varied by generational status would differ in their resistance to peer pressure. After controlling for gender, resistance to peer pressure varied significantly by generational status. Adolescents with no familial births in the United States were significantly more resistant to peer pressure than…

  4. Predicting Electrocardiogram and Arterial Blood Pressure Waveforms with Different Echo State Network Architectures

    Science.gov (United States)

    2014-11-01

    Predicting Electrocardiogram and Arterial Blood Pressure Waveforms with Different Echo State Network Architectures Allan Fong, MS1,3, Ranjeev...the medical staff in Intensive Care Units. The ability to predict electrocardiogram and arterial blood pressure waveforms can potentially help the...type of neural network for mining, understanding, and predicting electrocardiogram and arterial blood pressure waveforms. Several network

  5. Binding events of (S )-N -(3-oxo-octanoyl)-homoserine lactone with agrobacterium tumefaciens mutant cells studied by saturation transfer difference NMR

    Energy Technology Data Exchange (ETDEWEB)

    Cabeca, Luis Fernando; Pomini, Armando Mateus; Cruz, Pedro Luiz R.; Marsaioli, Anita J. [University of Campinas (UNICAMP), SP (Brazil). Chemistry Inst.

    2011-07-01

    Quorum-sensing is a widely studied communication phenomenon in bacteria, which involves the production and detection of signaling substances in relation with cell density and colony behavior. Herein, the membrane binding interactions of the signal (S)-N-(3-oxo-octanoyl)-HSL with A. tumefaciens NTL4(pZLR4) cells were studied using saturation transfer difference NMR spectroscopy (STD-NMR). The substance epitope map was obtained showing that the hydrophobic acyl chain is the most important interacting site for the signal and the cell membrane. Results were interpreted upon comparisons with a simpler system, using liposomes as membrane models. Some insights on the use of b-cyclodextrin as acyl-HSL carrier were also provided. (author)

  6. Interaction between Wine Phenolic Acids and Salivary Proteins by Saturation-Transfer Difference Nuclear Magnetic Resonance Spectroscopy (STD-NMR) and Molecular Dynamics Simulations.

    Science.gov (United States)

    Ferrer-Gallego, Raúl; Hernández-Hierro, José Miguel; Brás, Natércia F; Vale, Nuno; Gomes, Paula; Mateus, Nuno; de Freitas, Victor; Heredia, Francisco J; Escribano-Bailón, María Teresa

    2017-08-09

    The interaction between phenolic compounds and salivary proteins is highly related to the astringency perception. Recently, it has been proven the existence of synergisms on the perceived astringency when phenolic acids were tested as mixtures in comparison to individual compounds, maintaining constant the total amount of the stimulus. The interactions between wine phenolic acids and the peptide fragment IB712 have been studied by saturation-transfer difference (STD) NMR spectroscopy. This technique provided the dissociation constants and the percentage of interaction between both individual and mixtures of hydroxybenzoic and hydroxycinnamic acids and the model peptide. It is noteworthy that hydroxybenzoic acids showed higher affinity for the peptide than hydroxycinnamic acids. To obtain further insights into the mechanisms of interaction, molecular dynamics simulations have been performed. Results obtained not only showed the ability of these compounds to interact with salivary proteins but also may justify the synergistic effect observed in previous sensory studies.

  7. Pressure transmission and distribution under denture bases using denture teeth with different materials and cuspal angulations.

    Science.gov (United States)

    Arksornnukit, Mansuang; Phunthikaphadr, Thitima; Takahashi, Hidekazu

    2011-02-01

    Pressure transmission and distribution under denture bases may be variable depending on the different materials and cuspal angulations of denture teeth. The purpose of this study was to evaluate pressure transmission and distribution under impact load using denture teeth made with different materials and cuspal angulations. Three types (acrylic resin, microfilled composite resin, and ceramic) and 4 different cuspal angulations (0 degree, 20 degree, 33 degree, and 35 degree) of denture teeth were evaluated. Pressure transmission, distribution, and maximum pressure (n=10) were observed with pressure-sensitive sheets under an impact load. Data were statistically analyzed with 2-way ANOVA (α=.05) to determine significant interactions between denture tooth materials and cuspal angulations with respect to pressure transmission, followed by 1-way ANOVA (α=.05) to examine how materials and angulations jointly affected the pressure. Two 1-way ANOVAs were performed on the acrylic resin and ceramic denture teeth with the inclusion of 20-degree denture teeth groups. Tukey HSD and Tamhane's post hoc tests were used to evaluate data differences among groups. Denture tooth materials and cuspal angulations had significant interactions with respect to average pressure (P<.001) and maximum pressure transmission (P=.007). Zero-degree denture teeth showed significantly lower average and maximum pressures than 33- and 35-degree denture teeth for all 3 denture tooth materials (P<.001). Denture teeth with greater cuspal angulations demonstrated significantly higher average pressure transmission for all ceramic denture teeth groups (P<.05). Pressure transmission and distribution varied among denture teeth made of different materials and with different cuspal angulations. Cusped denture teeth presented significantly higher average pressure and maximum pressure transmission compared to 0-degree denture teeth. Copyright © 2011 The Editorial Council of the Journal of Prosthetic Dentistry

  8. Group epitope mapping considering relaxation of the ligand (GEM-CRL): Including longitudinal relaxation rates in the analysis of saturation transfer difference (STD) experiments

    Science.gov (United States)

    Kemper, Sebastian; Patel, Mitul K.; Errey, James C.; Davis, Benjamin G.; Jones, Jonathan A.; Claridge, Timothy D. W.

    2010-03-01

    In the application of saturation transfer difference (STD) experiments to the study of protein-ligand interactions, the relaxation of the ligand is one of the major influences on the experimentally observed STD factors, making interpretation of these difficult when attempting to define a group epitope map (GEM). In this paper, we describe a simplification of the relaxation matrix that may be applied under specified experimental conditions, which results in a simplified equation reflecting the directly transferred magnetisation rate from the protein onto the ligand, defined as the summation over the whole protein of the protein-ligand cross-relaxation multiplied by with the fractional saturation of the protein protons. In this, the relaxation of the ligand is accounted for implicitly by inclusion of the experimentally determined longitudinal relaxation rates. The conditions under which this "group epitope mapping considering relaxation of the ligand" (GEM-CRL) can be applied were tested on a theoretical model system, which demonstrated only minor deviations from that predicted by the full relaxation matrix calculations (CORCEMA-ST) [7]. Furthermore, CORCEMA-ST calculations of two protein-saccharide complexes (Jacalin and TreR) with known crystal structures were performed and compared with experimental GEM-CRL data. It could be shown that the GEM-CRL methodology is superior to the classical group epitope mapping approach currently used for defining ligand-protein proximities. GEM-CRL is also useful for the interpretation of CORCEMA-ST results, because the transferred magnetisation rate provides an additional parameter for the comparison between measured and calculated values. The independence of this parameter from the above mentioned factors can thereby enhance the value of CORCEMA-ST calculations.

  9. High pressure inactivation of relevant target microorganisms in poultry meat products and the evaluation of pressure-induced protein denaturation of marinated poultry under different high pressure treatments

    Science.gov (United States)

    Schmidgall, Johanna; Hertel, Christian; Bindrich, Ute; Heinz, Volker; Toepfl, Stefan

    2011-03-01

    In this study, the possibility of extending shelf life of marinated poultry meat products by high pressure processing was evaluated. Relevant spoilage and pathogenic strains were selected and used as target microorganisms (MOs) for challenge experiments. Meat and brine were inoculated with MOs and treated at 450 MPa, 4 °C for 3 min. The results of inactivation show a decreasing pressure tolerance in the series Lactobacillus > Arcobacter > Carnobacterium > Bacillus cereus > Brochothrix thermosphacta > Listeria monocytogenes. Leuconostoc gelidum exhibited the highest pressure tolerance in meat. A protective effect of poultry meat was found for L. sakei and L. gelidum. In parallel, the influence of different marinade formulations (pH, carbonates, citrates) on protein structure changes during a pressure treatment was investigated. Addition of sodium carbonate shows a protection against denaturation of myofibrillar proteins and provides a maximum water-holding capacity. Caustic marinades allowed a higher retention of product characteristics than low-pH marinades.

  10. Isosteric Vapor Pressure – Temperature Data for Water Sorption in Hardened Cement Paste: Enthalpy, Entropy and Sorption Isotherms at Different Temperatures

    DEFF Research Database (Denmark)

    Radjy, Fariborz; Sellevold, Erik J.; Hansen, Kurt Kielsgaard

    . The accuracies for pressure, enthalpy and entropy are found to be 0.5% or less. PART II: The TPA-system has been used to generate water vapor pressure – temperature data for room temperature – and steam cured hardened cement pastes as well as porous vycor glass. The moisture contents range from saturated to dry...... and the temperatures range from 2 to 95 °C, differing for the specimen types. The data has been analyzed to yield differential enthalpy and entropy of adsorption, as well as the dependence of the relative vapor pressure on temperature at various constant moisture contents. The implications for the coefficient...... of thermal expansion have been explored....

  11. Modeling Water Saturation Points in Natural Gas Streams Containing CO2 and H2S-Comparisons with Different Equations of State

    DEFF Research Database (Denmark)

    dos Santos, Leticia C.; Abunahman, Samir S.; Tavares, Frederico W.

    2015-01-01

    Since the discovery of the Pre-Salt layer in Brazilian waters, production of high gas-oil ratio (GOR) has increased considerably. This gas has a high content of water, CO2, and sometimes H2S. A study in different conditions was conducted using several equations of state (EoS) such as Peng...... to be used for predicting dew points for water-containing mixtures, especially at high pressures....

  12. Effects of different shoe-lacing patterns on dorsal pressure distribution during running and perceived comfort.

    Science.gov (United States)

    Hagen, Marco; Hömme, Ann-Kathrin; Umlauf, Tim; Hennig, Ewald M

    2010-07-01

    The purpose of this study was to investigate the effects of four lacing patterns (one regular, one tight, and two seven-eyelet lacings) on dorsal foot pressures during running and the perception of comfort and stability with 14 male rearfoot runners. By using a pressure insole, peak dorsal pressures were measured under the shoe's tongue. Highest peak pressures were found above the talus, the navicular bone, and the first ray. Seven-eyelet lacings showed a significant enhancement of perceived stability without differences in perceived comfort compared with a regular six-eyelet technique. Reduction of pressure on the talus, the navicular bone, and the extensor tendons is related to better comfort. With individually chosen special seven-eyelet lacings runners can improve foot-shoe coupling without increasing peak dorsal pressures on the tarsus. Knowledge of the location of the dorsal pressure distribution is useful for new tongue and lacing constructions to improve comfort in running shoes while maintaining stability.

  13. Prospective Comparative Analysis of 4 Different Intraocular Pressure Measurement Techniques and Their Effects on Pressure Readings.

    Science.gov (United States)

    Berk, Thomas A; Yang, Patrick T; Chan, Clara C

    2016-10-01

    To compare intraocular pressure (IOP) measurement using the Goldmann applanation tonometry (GAT) without fluorescein, with fluorescein strips, with fluorescein droplets, and IOP measurement with Tono-Pen Avia (TPA). This was a prospective comparative clinical analysis. It was performed in clinical practice. The study population consisted of 40 volunteer patients, 1 eye per patient. All patients who were 18 years and older having routine ophthalmological examination were eligible to participate. Active corneal abrasions and/or ulcers, previous glaucoma surgery, or prostheses interfering with GAT measurement were excluded. GAT IOP was measured first without fluorescein, then with fluorescein strip, then with fluorescein droplet, and finally with the TPA device. The main outcome measure was central corneal IOP. Mean±SD IOP measurements for GAT without fluorescein, with fluorescein strip, with fluorescein droplet, and for TPA groups were 12.65±3.01, 14.70±2.82, 15.78±2.64, and 16.33±3.08 mm Hg, respectively. Repeated-measures analysis of variance corrected with the Greenhouse-Geisser estimate ([Latin Small Letter Open E]=0.732) showed that measuring technique had a significant effect on IOP measurements (F2.20,85.59=34.66, Pmeasurement ranging from 5.89 mm Hg in the GAT with fluorescein strip versus droplet compared with 11.83 mm Hg in the GAT with fluorescein strip versus TPA comparison. IOP measurement technique significantly impacted the values obtained. The ophthalmologist should ensure consistent measurement technique to minimize variability when following patients.

  14. Nuclear reactions in deuterium-saturated palladium under irradiation by 10 MeV γ-quanta, in dense molecular deuterium at 1.2 kbar pressure

    Science.gov (United States)

    Didyk, A. Yu.; Wisniewski, R. S.

    2013-08-01

    A high-pressure chamber with a Pd-rod inside was filled up with 1.2 kbar molecular deuterium (DHPC). Then the saturated by deuterium palladium rod was irradiated during 18 hours by 11 MeV braking γ-quanta at 11-13 μA electron beam using the MT-25 electron accelerator. The element compositions of all the DHPC surfaces which had been in contact with dense deuterium gas were studied using scanning electronic microscopes with Roentgen microprobe analysis. It was determined that all the surfaces, including surfaces of the high-purity Pd-rod (99.995%), were covered either by a partially homogeneous layer or large microparticles of lead. Also, light elements as C, O, Na, Mg, Al, Si, Ti, Mn, Fe, Cu, Zn and heavy metals as Ag, Ta, W, Pt, Au and Pb were observed on the chambers inner surfaces.

  15. The difference in endolymphatic hydrostatic pressure elevation induced by isoproterenol between the ampulla and the cochlea.

    Science.gov (United States)

    Inamoto, Ryuhei; Miyashita, Takenori; Matsubara, Ai; Hoshikawa, Hiroshi; Mori, Nozomu

    2017-06-01

    The purpose of the study was to investigate the difference in the responses of endolymphatic hydrostatic pressure to isoproterenol, β-adrenergic receptor agonist, between pars superior and pars inferior. The hydrostatic pressure of endolymph and perilymph and endolymphatic potential in the ampulla and the cochlea during the intravenous administration of isoproterenol were recorded using a servo-null system in guinea pigs. The hydrostatic pressure of endolymph and perilymph in the ampulla and cochlea was similar in magnitude. Isoproterenol significantly increased hydrostatic pressure of ampullar and cochlear endolymph and perilymph with no change in the ampullar endolymphatic potential and endocochlear potential, respectively. The isoproterenol-induced maximum change of endolymphatic hydrostatic pressure in ampulla was significantly (ppressure in the ampulla disappeared like that in the cochlea. Isoproterenol elevates endolymphatic hydrostatic pressure in different manner between the vestibule and the cochlea. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  16. Experimental Study on Hydrate Induction Time of Gas-Saturated Water-in-Oil Emulsion using a High-Pressure Flow Loop

    Directory of Open Access Journals (Sweden)

    Lv X.F.

    2015-11-01

    Full Text Available Hydrate is one of the critical precipitates which have to be controlled for subsea flow assurance. The induction time of hydrate is therefore a significant parameter. However, there have been few studies on the induction time of the natural gas hydrate formation in a flow loop system. Consequently, a series of experiments were firstly performed, including water, natural gas and Diesel oil, on the hydrate induction time under various conditions such as the supercooling and supersaturation degree, water cut, anti-agglomerant dosage, etc. The experiments were conducted in a high-pressure hydrate flow loop newly constructed in the China University of Petroleum (Beijing, and dedicated to flow assurance studies. Then, based on previous research, this study puts forward a method for induction time, which is characterized by clear definition, convenient measurement and good generality. Furthermore, we investigated the influences of the experimental parameters and analyzed the experimental phenomena for the hydrate induction time in a flowing system.

  17. Age-related Differences in Tongue-Palate Pressures for Strength and Swallowing Tasks

    OpenAIRE

    Fei, Tiffany; Polacco, Rebecca Cliffe; Hori, Sarah E.; Molfenter, Sonja M.; Peladeau-Pigeon, Melanie; Tsang, Clemence; Steele, Catriona M.

    2013-01-01

    The tongue plays a key role in the generation of pressures for transporting liquids and foods through the mouth in swallowing. Recent studies suggest that there is an age-related decline in tongue strength in healthy adults. However, whether age-related changes occur in tongue pressures generated for the purpose of swallowing remains unclear. Prior literature in this regard does not clearly explore the influence of task on apparent age-related differences in tongue pressure amplitudes. Furthe...

  18. Pressure transmission and distribution under impact load using artificial denture teeth made of different materials.

    Science.gov (United States)

    Phunthikaphadr, Thitima; Takahashi, Hidekazu; Arksornnukit, Mansuang

    2009-11-01

    Pressure transmission and distribution under denture bases may be different depending on the material of the artificial denture teeth used. The purposes of this study were to evaluate pressure transmission and distribution under impact load using artificial denture teeth composed of different materials, and to examine the modulus of elasticity of the artificial denture teeth. The denture base specimens with artificial denture teeth made of 4 different materials (acrylic resin, microfilled composite resin, nanocomposite resin, and ceramic) were evaluated. Pressure transmission, distribution, and maximum pressure (n=10) were observed with pressure-sensitive sheets under an impact load. Modulus of elasticity of the artificial denture teeth (n=10) was measured by using an ultramicroindentation system. Data were statistically analyzed with 1-way ANOVA, followed by Tukey HSD and Tamhane's multiple range post hoc tests (alpha=.05). Maximum pressure transmission observed from ceramic denture teeth was significantly higher than that of other groups (P<.001). Nanocomposite resin denture teeth presented the lowest pressure transmission, whereas a localized stress transmission area was observed in the ceramic denture teeth group. Significant differences in the modulus of elasticity were observed among the 4 types of artificial denture teeth (P<.001). Pressure transmission and distribution varied among the denture tooth materials. Differences in the modulus of elasticity of each type of denture tooth were demonstrated.

  19. Assessment of plantar pressure in hindfoot relief shoes of different designs.

    Science.gov (United States)

    Hahn, Thomas; Carl, Hans-Dieter; Jendrissek, Andreas; Brem, Matthias; Swoboda, Bernd; Rummel, Philipp; Pauser, Johannes

    2014-01-01

    Although there are several different concepts of hindfoot relief footwear, there are no studies on the extent of pressure reduction to be achieved by this footwear. Therefore, we sought to evaluate the reduction in plantar pressure to be achieved with two different hindfoot relief shoes. Ten healthy volunteers performed three trials at a self-selected speed. Peak pressure values in mass-produced shoes (normal gait) were considered as 100% and were compared with measurements in two differently designed hindfoot relief shoes. Foot portions were defined as heel (0%-15% of total insole length), hindfoot (16%-30%), midfoot (31%-60%), and forefoot (61%-100%). Heel and hindfoot peak pressures were significantly reduced in both shoes compared with normal gait (P shoes. Midfoot peak pressure was not significantly reduced in tested shoes compared with baseline (P > .05) but differed significantly between the two shoes. Forefoot peak pressure was significantly reduced with one of the tested shoes (to a median 73% baseline; P = .004) but not with the other (median, 88% baseline). Hindfoot relief shoes leave a considerable amount of peak pressure, predominantly under the hindfoot. The extent of peak pressure reduction for the heel and the hindfoot varies between different hindfoot relief shoes. Depending on the affected foot area, the kind of hindfoot relief shoe should be carefully chosen.

  20. Comparison of plantar pressure between flat and normal feet when crossing an obstacle at different heights.

    Science.gov (United States)

    Han, Jin-Tae; Lee, Jung-Hoon; Lee, Eun-Ju; Lim, Chang-Hun; Kim, Won-Bok

    2015-01-01

    The purpose of this study is to compare the plantar foot pressure and the center of pressure (COP) pathway of normal and flat feet while crossing an obstacle at different heights. Nineteen subjects (10 normal feet, 9 flat feet) participated in this study. The plantar foot surface was divided into the following seven regions for pressure measurement: two toe regions, three forefoot regions, one midfoot region, and one heel region. A one-way ANOVA with repeated measurements was used to compare the plantar foot pressure of normal and flat feet according to the obstacle height. The trend analysis showed a quadratic trend during level walking for the normal foot group, but a linear trend appeared as the obstacle height increased. In the flat foot group, the trend analysis showed a linear trend regardless of the obstacle height. In the 2nd-3rd metatarsal head region, the plantar pressure of the flat foot group increased more than the normal foot group as the obstacle height increased; however, in the 4th-5th metatarsal head region, the plantar pressure in flat feet was lower than in normal feet. In the heel region, the plantar pressure in both groups generally increased as the obstacle height increased, but the plantar pressure in the flat foot group was lower than in the normal foot group. We believe that, due to a loss of longitudinal arch, the COP path and plantar pressure of flat feet may be different from normal feet when crossing obstacles of different heights.

  1. Comparison between frictional behavior of the soft and brittle materials at different contact pressures

    Directory of Open Access Journals (Sweden)

    Mehdi Eskandarzade

    2017-06-01

    Full Text Available Miavaghi, A. Kangarlou, H. and Eskandarzade, M. 2017. Comparison between frictional behavior of the soft and brittle materials at different contact pressures. Lebanese Science Journal. 18(1: 98-105. Coefficient of friction changed significantly by the change in contact pressure. Experimental measurement of the coefficient of friction in different contact pressures can be useful in numerical and analytical analysis of many engineering problems, such as metal forming process. This study dedicated to investigate the sensitivity of the friction coefficient to changes in contact pressures. To aim this goal the special tribometer device has been fabricated and the coefficient of friction of the soft and brittle metals when sliding with a low speed on a rigid body are measured for different contact pressures. The friction sensitivity of the soft (copper and aluminum and brittle (steel samples to changes in contact pressure are compared and discussed. The results showed that both brittle and soft metals are highly sensitive for change in contact pressure but their behaviour is slightly different. While the coefficient of friction of the steel sample when sliding on a steel substrate is reduced sharply by a little increase in contact pressure; the coefficient of friction of the soft material when sliding on a steel substrate is reduced slowly depending on the magnetude of the applied normal load.

  2. Ethnic differences in the association of birth weight and blood pressure

    NARCIS (Netherlands)

    Oberg, Sara; Ge, Dongliang; Cnattingius, Sven; Svensson, Anna; Treiber, Frank A.; Snieder, Harold; Iliadou, Anastasia

    2007-01-01

    Background: African Americans (AAs) not only have higher blood-pressure levels, but also an increased risk of low weight at birth, compared with European Americans (EAs). In light of fetal programming theories, it has been suggested that ethnic differences in blood pressure originate in utero.

  3. Determination of dynamic pressure on infinite piezoelectric hollow cylinder from electric potential difference measurement

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H.M. [Department of Mechanics, School of Aeronautics and Astronautics, Zhejiang University, Hangzhou 310027 (China)], E-mail: wanghuiming@zju.edu.cn; Ding, H.J. [Department of Civil Engineering, College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310027 (China)

    2009-06-15

    An analytical method is developed for evaluating the dynamic pressure acted at the surface of infinite piezoelectric hollow cylinder by measuring the electric potential difference between the internal and external surfaces. By virtue of the separation of variables method and the orthogonal expansion technique, the inverse boundary problem is transformed to a second kind Volterra integral equation about the unknown dynamic pressure. The interpolation method is employed to solve the integral equation and the dynamic pressure is determined. The present method is suitable for the hollow cylinder with arbitrary thickness subjected to arbitrary dynamic pressure. Numerical experiments are also presented.

  4. Thermal power transfer system using applied potential difference to sustain operating pressure difference

    Science.gov (United States)

    Bhandari, Pradeep (Inventor); Fujita, Toshio (Inventor)

    1991-01-01

    A thermal power transfer system using a phase change liquid gas fluid in a closed loop configuration has a heat exchanger member connected to a gas conduit for inputting thermal energy into the fluid. The pressure in the gas conduit is higher than a liquid conduit that is connected to a heat exchanger member for outputting thermal energy. A solid electrolyte member acts as a barrier between the gas conduit and the liquid conduit adjacent to a solid electrolyte member. The solid electrolyte member has the capacity of transmitting ions of a fluid through the electrolyte member. The ions can be recombined with electrons with the assistance of a porous electrode. An electrical field is applied across the solid electrolyte member to force the ions of the fluid from a lower pressure liquid conduit to the higher pressure gas conduit.

  5. Saturated poroelastic actuators generated by topology optimization

    DEFF Research Database (Denmark)

    Andreasen, Casper Schousboe; Sigmund, Ole

    2011-01-01

    In this paper the fluid-structure interaction problem of a saturated porous media is considered. The pressure coupling properties of porous saturated materials change with the microstructure and this is utilized in the design of an actuator using a topology optimized porous material. By maximizing...... the coupling of internal fluid pressure and elastic shear stresses a slab of the optimized porous material deflects/deforms when a pressure is imposed and an actuator is created. Several phenomenologically based constraints are imposed in order to get a stable force transmitting actuator....

  6. A method for mapping topsoil field-saturated hydraulic conductivity in the Cévennes-Vivarais region using infiltration tests conducted with different techniques

    Science.gov (United States)

    Braud, Isabelle; Desprats, Jean-François; Ayral, Pierre-Alain; Bouvier, Christophe; Vandervaere, Jean-Pierre

    2017-04-01

    Topsoil field-saturated hydraulic conductivity, Kfs, is a parameter that controls the partition of rainfall between infiltration and runoff. It is a key parameter in most distributed hydrological models. However, there is a mismatch between the scale of local in situ measurements and the scale at which the parameter is required in models. Therefore it is necessary to design methods to regionally map this parameter at the model scale. The paper propose a method for mapping Kfs in the Cévennes-Vivarais region, south-east France, using more easily available GIS data: geology and land cover. The mapping is based on a data set gathering infiltration tests performed in the area or close to it for more than ten years. The data set is composed of infiltration tests performed using various techniques: Guelph permeameter, double ring and single ring infiltration tests, infiltrometers with multiple suctions. The different methods lead to different orders of magnitude for Kfs rendering the pooling of all the data challenging. Therefore, a method is first proposed to pool the data from the different infiltration methods, leading to a homogenized set of Kfs, based on an equivalent double ring/tension disk infiltration value. Statistical tests showed significant differences in distributions among different geologies and land covers. Thus those variables were retained as proxy for mapping Kfs at the regional scale. This map was compared to a map based on the Rawls and Brakensiek (RB) pedo-transfer function (Manus et al., 2009, Vannier et al., 2016), showing very different patterns between both maps. In addition, RB values did not fit observed values at the plot scale, highlighting that soil texture only is not a good predictor of Kfs. References Manus, C., Anquetin, S., Braud, I., Vandervaere, J.P., Viallet, P., Creutin, J.D., Gaume, E., 2009. A modelling approach to assess the hydrological response of small Mediterranean catchments to the variability of soil characteristics in a

  7. Saturated Switching Systems

    CERN Document Server

    Benzaouia, Abdellah

    2012-01-01

    Saturated Switching Systems treats the problem of actuator saturation, inherent in all dynamical systems by using two approaches: positive invariance in which the controller is designed to work within a region of non-saturating linear behaviour; and saturation technique which allows saturation but guarantees asymptotic stability. The results obtained are extended from the linear systems in which they were first developed to switching systems with uncertainties, 2D switching systems, switching systems with Markovian jumping and switching systems of the Takagi-Sugeno type. The text represents a thoroughly referenced distillation of results obtained in this field during the last decade. The selected tool for analysis and design of stabilizing controllers is based on multiple Lyapunov functions and linear matrix inequalities. All the results are illustrated with numerical examples and figures many of them being modelled using MATLAB®. Saturated Switching Systems will be of interest to academic researchers in con...

  8. Pressure generated on a simulated oral analog by impression materials in custom trays of different designs.

    Science.gov (United States)

    Masri, Radi; Driscoll, Carl F; Burkhardt, John; Von Fraunhofer, Anthony; Romberg, Elaine

    2002-09-01

    To measure the pressure exerted by maxillary edentulous impressions composed of 3 commonly used impression materials using four different impression tray configurations. The study was performed using an oral analog that simulated an edentulous maxillary arch. Three pressure transducers were imbedded in the oral analog, 1 in the mid-palate area and the other 2 in the right and left ridge (maxillary first premolar areas). Custom trays of 4 different configurations were fabricated. The 3 impression materials tested were irreversible hydrocolloid, light-body and medium-body vinyl polysiloxane, and polysulfide. A total of 128 impressions were made. The custom tray and the oral analog were mounted using a reline jig. A Satec universal testing machine was used to apply a constant pressure of 2 kg/cm(2) over a period of 5 minutes on the loaded custom tray. The pressure was recorded every 10 seconds. Factorial analysis of variance and Tukey's multiple comparison test were used to analyze the results. A significant difference in the pressure produced using different impression materials was found (p < or =0.001). Irreversible hydrocolloid and medium-body vinyl polysiloxane produced a significantly higher pressure than light-body vinyl polysiloxane and polysulfide impression materials. The presence of holes and/or relief did not significantly alter the magnitude of pressure. All impression materials produced pressure during maxillary edentulous impression making. Tray modification was not important in changing the amount of pressure produced. The impression materials used had more effect on the pressure produced during impression making on the simulated oral analog. Copyright 2002 by The American College of Prosthodontists.

  9. EXPERIMENTAL RESEARCH ON LATERAL PRESSURE OF GRANULAR MEDIA WITHIN CLOSELY SPACED WALLS CONSIDERING DIFFERENT FILLING CONDITIONS

    Directory of Open Access Journals (Sweden)

    Aleksej Aniskin

    2016-12-01

    Full Text Available This article presents the results of an original experimental research on the lateral pressure acting on closely spaced rigid walls at different angles of granular particle orientation to the horizontal line. Filling was performed at three different predominant angles of grain orientation with respect to the horizontal line: 0°, 45°, and 90°. The aim of the study is to determine the nature of the influence of the particle orientation achieved by filling on the characteristics and distribution of the lateral pressure. In the experiments, a composite medium, i.e. a mixture of quartz sand and flat shell particles in a volume ratio of 2:1, was used. The results of the experiments showed a significant difference in the lateral pressure at different angles of particle orientation. It was found that at an angle of 90°, the average lateral pressure was 44.2% more than that at an angle of 0°.

  10. Ethnic differences in sleep duration at 5 years, and its relationship with overweight and blood pressure

    NARCIS (Netherlands)

    Anujuo, Kenneth O.; Vrijkotte, Tanja G. M.; Stronks, Karien; Jean-Louis, Girardin; Agyemang, Charles O.

    2016-01-01

    Background: Studies on adult population indicate shorter sleep duration in ethnic minority groups than host populations. We examined ethnic differences in sleep duration and its relationship with overweight and blood pressure (BP) among children living in Amsterdam. Methods: Participants include

  11. Race and sex differences in the correlates of blood pressure change.

    Science.gov (United States)

    Daniels, S R; Heiss, G; Davis, C E; Hames, C G; Tyroler, H A

    1988-03-01

    Potential predictors of systolic and diastolic blood pressure change between 1960 and 1967 in the biracial population of Evans County, Georgia, were investigated. An all possible regressions multiple linear regression analysis was used. For systolic blood pressure change, the level of systolic blood pressure, age, and change in Quetelet index were significant (p less than 0.05) correlates in white men. The level of systolic blood pressure, the level and change of socioeconomic status, change in Quetelet index, and change in cholesterol were significant correlates for white women. The level of Quetelet index was of borderline significance (p less than 0.055) when the other significant variables were included in the model for white women. The change in Quetelet index was the only significant correlate of systolic blood pressure change in blacks. For diastolic blood pressure change, age, change in hematocrit, and change in Quetelet index were significant correlates for white men. Age, level and change of socioeconomic status, level and change of Quetelet index, and change in hematocrit were the significant correlates in white women. In black men, change in Quetelet index and age were significant. In black women, only age was a significant correlate of diastolic blood pressure change. These results indicate that there may be important differences in these correlates between race-sex groups and thus in the mechanism of blood pressure change for different race-sex groups. groups.

  12. Differences in pressure and temperature transitions of proteins and polymer gels

    Directory of Open Access Journals (Sweden)

    Kunugi S.

    2005-01-01

    Full Text Available Pressure-driven and temperature-driven transitions of two thermoresponsive polymers, poly(N-isopropylacrylamide (pNIPAM and poly(N-vinylisobutyramide (pNVIBA, in both a soluble linear polymer form and a cross-linked hydro-gel form, were examined by a dynamic light-scattering method and direct microscopic observation, respectively. Their behavior was compared with that of protein systems. Changes in some characteristic parameters in the time-intensity correlation functions of dynamic light-scattering measurement of aqueous solutions of pNIPAM at various pressures and temperatures showed no essential differences during temperature and pressure scanning and, as a whole, the motions of polymers in aqueous solutions were similar in two types of transitions until chain shrinkage occurred. The gels (cross-linked polymer gels prepared from the thermoresponsive polymers also showed similar volume transitions responding to the pressure and temperature increase. In temperature transitions, however, gels showed drastic volume shrinkage with loss of transparency, while pressure-induced transition showed a slow recovery of transparency while keeping the size, after first transient drastic volume shrinkage with loss of transparency. At a temperature slightly higher than the transition under atmospheric temperature, so-called reentry of the volume change and recovery of the transparency were observed during the pressure-increasing process, which implies much smaller aggregation or non-aggregated collapsed polymer chains in the gel at higher pressures, indicating a certain mechanistic difference of the dehydration processes induced by temperature and pressure.

  13. Estimating Chlorophyll Fluorescence Parameters Using the Joint Fraunhofer Line Depth and Laser-Induced Saturation Pulse (FLD-LISP Method in Different Plant Species

    Directory of Open Access Journals (Sweden)

    Parinaz Rahimzadeh-Bajgiran

    2017-06-01

    Full Text Available A comprehensive evaluation of the recently developed Fraunhofer line depth (FLD and laser-induced saturation pulse (FLD-LISP method was conducted to measure chlorophyll fluorescence (ChlF parameters of the quantum yield of photosystem II (ΦPSII, non-photochemical quenching (NPQ, and the photosystem II-based electron transport rate (ETR in three plant species including paprika (C3 plant, maize (C4 plant, and pachira (C3 plant. First, the relationships between photosynthetic photon flux density (PPFD and ChlF parameters retrieved using FLD-LISP and the pulse amplitude-modulated (PAM methods were analyzed for all three species. Then the relationships between ChlF parameters measured using FLD-LISP and PAM were evaluated for the plants in different growth stages of leaves from mature to aging conditions. The relationships of ChlF parameters/PPFD were similar in both FLD-LISP and PAM methods in all plant species. ΦPSII showed a linear relationship with PPFD in all three species whereas NPQ was found to be linearly related to PPFD in paprika and maize, but not for pachira. The ETR/PPFD relationship was nonlinear with increasing values observed for PPFDs lower than about 800 μmol m−2 s−1 for paprika, lower than about 1200 μmol m−2 s−1 for maize, and lower than about 800 μmol m−2 s−1 for pachira. The ΦPSII, NPQ, and ETR of both the FLD-LISP and PAM methods were very well correlated (R2 = 0.89, RMSE = 0.05, (R2 = 0.86, RMSE = 0.44, and (R2 = 0.88, RMSE = 24.69, respectively, for all plants. Therefore, the FLD-LISP method can be recommended as a robust technique for the estimation of ChlF parameters.

  14. Utility of labile plasma iron and transferrin saturation in addition to serum ferritin as iron overload markers in different underlying anemias before and after deferasirox treatment.

    Science.gov (United States)

    Porter, John B; El-Alfy, Mohsen; Viprakasit, Vip; Giraudier, Stephane; Chan, Lee Lee; Lai, Yongrong; El-Ali, Ali; Han, Jackie; Cappellini, Maria D

    2016-01-01

    Plasma markers in addition to serum ferritin (SF) may be useful for the assessment of iron overload; however, predictive utility may differ depending on underlying, transfusion-dependent, anemias. Data were collected before and after 1 year of deferasirox treatment (end of study; EOS) from the large, 1-year EPIC (Evaluation of Patients' Iron Chelation with Exjade(®) ) study. Trends were evaluated between liver iron concentration (LIC), transferrin saturation (TfSat), predose labile plasma iron (LPI) and their relationship to SF categories in 1530 patients: thalassemia major (TM; n = 1114), myelodysplastic syndromes (MDS, n = 336), and sickle-cell disease (SCD, n = 80). Baseline and EOS SF values showed a clear and similar relationship to LIC for all disease groups. TfSat also showed a relationship to SF, most clearly in patients with SCD, where TfSat was lowest in the lowest relative SF category. Unlike SF or LIC, TfSat did not decrease at EOS in any disease group. Baseline LPI was raised in TM and MDS, but not in patients with SCD, decreasing at EOS in both patient groups. After 1 year of chelation therapy, there was a significant trend for greater LPI reduction in patients with TM achieving LIC <7 mg Fe/g dw (P = 0.0137). Despite limitations, SF showed the clearest relationship, of the plasma markers evaluated, to LIC before and after 1 year of deferasirox in patients with TM, MDS, and SCD. In patients with TM, changes in LPI with chelation show a significant relationship to EOS LIC and may provide an additional indicator of chelation response (clinicaltrials.gov identifier: NCT00171821). © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. Dietary fiber and saturated fat intake associations with cardiovascular disease differ by sex in the Malmö Diet and Cancer Cohort: a prospective study.

    Directory of Open Access Journals (Sweden)

    Peter Wallström

    Full Text Available BACKGROUND: The aim of the study was to examine associations between intake of macronutrients and dietary fiber and incident ischemic cardiovascular disease (iCVD in men and women. METHODS: We used data from 8,139 male and 12,535 female participants (aged 44-73 y of the Swedish population-based Malmö Diet and Cancer cohort. The participants were without history of CVD and diabetes mellitus, and had reported stable dietary habits in the study questionnaire. Diet was assessed by a validated modified diet history method, combining a 7-d registration of cooked meals and cold beverages, a 168-item food questionnaire (covering other foods and meal patterns, and a 1-hour diet interview. Sociodemographic and lifestyle data were collected by questionnaire. iCVD cases, which included coronary events (myocardial infarctions or deaths from chronic ischemic heart disease and ischemic strokes, were ascertained via national and local registries. Nutrient-disease associations were examined by multivariate Cox regressions. RESULTS: During a mean follow-up of 13.5 years, we identified 1,089 male and 687 female iCVD cases. High fiber intakes were associated with lower incidence rates of iCVD in women and of ischemic stroke in men. In post-hoc analysis, we discovered statistically significant interactions between intake of fiber and saturated fat; these interactions also differed between men and women (p<0.001. CONCLUSIONS: In this well-defined population, a high fiber intake was associated with lower risk of iCVD, but there were no robust associations between other macronutrients and iCVD risk. Judging from this study, gender-specific nutrient analysis may be preferable in epidemiology.

  16. Dietary fiber and saturated fat intake associations with cardiovascular disease differ by sex in the Malmö Diet and Cancer Cohort: a prospective study.

    Science.gov (United States)

    Wallström, Peter; Sonestedt, Emily; Hlebowicz, Joanna; Ericson, Ulrika; Drake, Isabel; Persson, Margaretha; Gullberg, Bo; Hedblad, Bo; Wirfält, Elisabet

    2012-01-01

    The aim of the study was to examine associations between intake of macronutrients and dietary fiber and incident ischemic cardiovascular disease (iCVD) in men and women. We used data from 8,139 male and 12,535 female participants (aged 44-73 y) of the Swedish population-based Malmö Diet and Cancer cohort. The participants were without history of CVD and diabetes mellitus, and had reported stable dietary habits in the study questionnaire. Diet was assessed by a validated modified diet history method, combining a 7-d registration of cooked meals and cold beverages, a 168-item food questionnaire (covering other foods and meal patterns), and a 1-hour diet interview. Sociodemographic and lifestyle data were collected by questionnaire. iCVD cases, which included coronary events (myocardial infarctions or deaths from chronic ischemic heart disease) and ischemic strokes, were ascertained via national and local registries. Nutrient-disease associations were examined by multivariate Cox regressions. During a mean follow-up of 13.5 years, we identified 1,089 male and 687 female iCVD cases. High fiber intakes were associated with lower incidence rates of iCVD in women and of ischemic stroke in men. In post-hoc analysis, we discovered statistically significant interactions between intake of fiber and saturated fat; these interactions also differed between men and women (pfiber intake was associated with lower risk of iCVD, but there were no robust associations between other macronutrients and iCVD risk. Judging from this study, gender-specific nutrient analysis may be preferable in epidemiology.

  17. Empirical Formulas for Calculation of Negative Pressure Difference in Vacuum Pipelines

    Directory of Open Access Journals (Sweden)

    Marek Kalenik

    2015-10-01

    Full Text Available The paper presents the analysis of results of empirical investigations of a negative pressure difference in vacuum pipelines with internal diameters of 57, 81, 102 mm. The investigations were performed in an experimental installation of a vacuum sewage system, built in a laboratory hall on a scale of 1:1. The paper contains a review of the literature concerning two-phase flows (liquid-gas in horizontal, vertical and diagonal pipelines. It presents the construction and working principles of the experimental installation of vacuum sewage system in steady and unsteady conditions during a two-phase flow of water and air. It also presents a methodology for determination of formula for calculation of a negative pressure difference in vacuum pipelines. The results obtained from the measurements of the negative pressure difference Δpvr in the vacuum pipelines were analyzed and compared with the results of calculations of the negative pressure difference Δpvr, obtained from the determined formula. The values of the negative pressure difference Δpvr calculated for the vacuum pipelines with internal diameters of 57, 81, and 102 mm with the use of Formula (19 coincide with the values of Δpvr measured in the experimental installation of a vacuum sewage system. The dependence of the negative pressure difference Δpvr along the length of the vacuum pipelines on the set negative pressure in the vacuum container pvzp is linear. The smaller the vacuum pipeline diameter, the greater the negative pressure difference Δpvr is along its length.

  18. Different in the prospective association between individual plasma phospholipid saturated fatty acids and incident type 2 diabetes: the EPIC-InterAct case-cohort study

    NARCIS (Netherlands)

    Forouhi, N.G.; Koulman, A.; Sharp, S.J.; Groenendijk-van Woudenbergh, G.J.; Feskens, E.J.M.

    2014-01-01

    Background Conflicting evidence exists regarding the association between saturated fatty acids (SFAs) and type 2 diabetes. In this longitudinal case-cohort study, we aimed to investigate the prospective associations between objectively measured individual plasma phospholipid SFAs and incident type 2

  19. Evolution effects of the copper surface morphology on the nucleation density and growth of graphene domains at different growth pressures

    Science.gov (United States)

    Hedayat, Seyed Mahdi; Karimi-Sabet, Javad; Shariaty-Niassar, Mojtaba

    2017-03-01

    In this work, we study the influence of the surface morphology of the catalytic copper substrate on the nucleation density and the growth rate of graphene domains at low and atmospheric pressure chemical vapor deposition (LPCVD and APCVD) processes. In order to obtain a wide range of initial surface morphology, precisely controlled electropolishing methods were developed to manipulate the roughntreess value of the as-received Cu substrate (RMS = 30 nm) to ultra-rough (RMS = 130 nm) and ultra-smooth (RMS = 2 nm) surfaces. The nucleation and growth of graphene domains show obviously different trends at LPCVD and APCVD conditions. In contrast to APCVD condition, the nucleation density of graphene domains is almost equal in substrates with different initial roughness values at LPCVD condition. We show that this is due to the evolution of the surface morphology of the Cu substrate during the graphene growth steps. By stopping the surface sublimation of copper substrate in a confined space saturated with Cu atoms, the evolution of the Cu surface was impeded. This results in the reduction of the nucleation density of graphene domains up to 24 times in the pre-smoothed Cu substrates at LPCVD condition.

  20. A Relationship between Tyre Pressure and Rolling Resistance Force under Different Vehicle Speed

    Directory of Open Access Journals (Sweden)

    Suyabodha Apiwat

    2017-01-01

    Full Text Available Tyres are a final output torque of the vehicle before all the forces are distributed to the road surface as a tractive force. When the tyre pressure changed, it had a direct effect on rolling resistance force of the vehicle and reduced the tractive force. Moreover, it had an effect on a rate of fuel consumption and driving comfort. This research had tested the effect of tyre pressure of 25 psi and 45 psi to determine the total resistance force between the vehicle speed from 40 km/hr to 100 km/hr and compare with the reference tyre pressure of 35 psi by using the “coast-down technique”. The results from calculation showed the total resistance force when the vehicle speed was zero from tyre pressure of 25 psi increased by 48.52% from reference value and the total resistance force from tyre pressure of 45 psi decreased by 13.46% from the reference tyre pressure. The different resistance force from tyre pressure of 35 psi with the other 2 values of tyre pressure in the research were called the different rolling resistance force because the vehicle changed only tyre pressure which had no effect on aerodynamics drag. The relationship of the different rolling resistance force along the test speed from tyre pressure of 25 psi and 45 psi decreased while the vehicle speed increased. The relationship can be fitted with a linear equation. The slope from tyre pressure of 25 psi was 0.2358 which was steeper than the slope of 0.0828 from 45 psi tyre pressure. These were the effect of tyre characteristic that made from rubber. When the vehicle speed was low, the frequency of tyre deformation was also low and resulted in high energy loss from hysteresis phenomena. Therefore high rolling resistance force was generated. Considering the effect of tyre under high vehicle speed, the frequency of tyre deformation increased and made the molecule of rubber vibrate more than low vehicle speed. These effects made the tyre stiffer than low frequency and resulted in

  1. Lipid order, saturation and surface property relationships: a study of human meibum saturation.

    Science.gov (United States)

    Mudgil, Poonam; Borchman, Douglas; Yappert, Marta C; Duran, Diana; Cox, Gregory W; Smith, Ryan J; Bhola, Rahul; Dennis, Gary R; Whitehall, John S

    2013-11-01

    Tear film stability decreases with age however the cause(s) of the instability are speculative. Perhaps the more saturated meibum from infants may contribute to tear film stability. The meibum lipid phase transition temperature and lipid hydrocarbon chain order at physiological temperature (33 °C) decrease with increasing age. It is reasonable that stronger lipid-lipid interactions could stabilize the tear film since these interactions must be broken for tear break up to occur. In this study, meibum from a pool of adult donors was saturated catalytically. The influence of saturation on meibum hydrocarbon chain order was determined by infrared spectroscopy. Meibum is in an anhydrous state in the meibomian glands and on the surface of the eyelid. The influence of saturation on the surface properties of meibum was determined using Langmuir trough technology. Saturation of native human meibum did not change the minimum or maximum values of hydrocarbon chain order so at temperatures far above or below the phase transition of human meibum, saturation does not play a role in ordering or disordering the lipid hydrocarbon chains. Saturation did increase the phase transition temperature in human meibum by over 20 °C, a relatively high amount. Surface pressure-area studies showing the late take off and higher maximum surface pressure of saturated meibum compared to native meibum suggest that the saturated meibum film is quite molecularly ordered (stiff molecular arrangement) and elastic (molecules are able to rearrange during compression and expansion) compared with native meibum films which are more fluid agreeing with the infrared spectroscopic results of this study. In saturated meibum, the formation of compacted ordered islands of lipids above the surfactant layer would be expected to decrease the rate of evaporation compared to fluid and more loosely packed native meibum. Higher surface pressure observed with films of saturated meibum compared to native meibum

  2. Effect of high-pressure homogenization on different matrices of food supplements.

    Science.gov (United States)

    Martínez-Sánchez, Ascensión; Tarazona-Díaz, Martha Patricia; García-González, Antonio; Gómez, Perla A; Aguayo, Encarna

    2016-12-01

    There is a growing demand for food supplements containing high amounts of vitamins, phenolic compounds and mineral content that provide health benefits. Those functional compounds have different solubility properties, and the maintenance of their compounds and the guarantee of their homogenic properties need the application of novel technologies. The quality of different drinkable functional foods after thermal processing (0.1 MPa) or high-pressure homogenization under two different conditions (80 MPa, 33 ℃ and 120 MPa, 43 ℃) was studied. Physicochemical characteristics and sensory qualities were evaluated throughout the six months of accelerated storage at 40 ℃ and 75% relative humidity (RH). Aroma and color were better maintained in high-pressure homogenization-treated samples than the thermally treated ones, which contributed significantly to extending their shelf life. The small particle size obtained after high-pressure homogenization treatments caused differences in turbidity and viscosity with respect to heat-treated samples. The use of high-pressure homogenization, more specifically, 120 MPa, provided active ingredient homogeneity to ensure uniform content in functional food supplements. Although the effect of high-pressure homogenization can be affected by the food matrix, high-pressure homogenization can be implemented as an alternative to conventional heat treatments in a commercial setting within the functional food supplement or pharmaceutical industry. © The Author(s) 2016.

  3. Differences in foot sensitivity and plantar pressure between young adults and elderly.

    Science.gov (United States)

    Machado, Álvaro S; Bombach, Gabriéli D; Duysens, Jacques; Carpes, Felipe P

    2016-01-01

    The understanding of foot sensitivity and plantar pressure contributes to the design of insoles, shoes, as well as to guide therapeutic interventions. Here we investigate differences in plantar pressure and foot sensitivity between young adults and community-dwelling elderly. Thirty-eight participants (19 young adults and 19 elderly) underwent clinical assessment of foot sensitivity and upright standing with eyes open and closed for measurement of plantar pressure in each foot. Data were compared between feet, groups, and visual conditions. Foot sensitivity was lower in the elderly and, in contrast to young adults, differed between the foot regions (loss of sensitivity was primarily seen at the heel). Elderly shift plantar pressure to more distal foot zones, namely towards midfoot and forefoot. Asymmetries in foot sensitivity and plantar pressure were not observed. Visual condition did not influence plantar pressure distribution. The forward shift in plantar pressure (away from the insensitive heel) constitutes a strategy of elderly to maintain balance. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  4. UV-visible reflectance spectra of nanocrystalline silver compacted under different pressures

    Energy Technology Data Exchange (ETDEWEB)

    Lu Yanwu [Department of Physics, Beijing Jiaotong University, Beijing 100044 (China)]. E-mail: ywlu@ustc.edu; Zhang Hongfei [Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Liu Fangxin [Department of Astronomy and Applied Physics, University of Science and Technology of China, Hefei 230026 (China)]. E-mail: fxliu@ustc.edu.cn

    2005-06-20

    Nanocrystalline silver samples compacted under different pressures have been studied by X-ray diffraction and ultraviolet-visible reflectance spectroscopy. It is shown that the reflectance spectra exhibit an intense band at 315 nm, three weak bands at about 240, 380 and 490 nm, and a long tail at the long-wavelength side. Their origins are given. With increasing the compacting pressure, an opposite peak-shift effect of the surface plasmon resonance (SPR) was observed. It is concluded that the collaborating effects of particle aggregate and the unit-cell contraction both induced by the compacting pressure can explain these variations.

  5. Features of blood pressure in student-athletes from different directions of the training process.

    Directory of Open Access Journals (Sweden)

    Kalenichenko Aleksej Vladimirovich

    2011-11-01

    Full Text Available Performed blood pressure (BP and hemodynamics of 85 students: 30 non-athletes (group I, 27 athletes power enforcement types (group II and 28 - endurance sports (group III. It was found that the second and third groups had higher systolic and mean arterial pressure than in the I group. There are differences in blood pressure reactivity to changes in body position, mental and physical activity among the various groups studied. It is shown that the formation of moderate hypertension in group III is carried out by increasing peripheral vascular resistance, and II - at the expense of increased cardiac output.

  6. Releasing H2 molecules with a partial pressure difference without the use of temperature

    Science.gov (United States)

    Lee, Hoonkyung; Huang, Bing; Duan, Wenhui; Ihm, Jisoon

    2010-08-01

    Using the pseudopotential density-functional method as well as equilibrium thermodynamic functions, we explore the process of releasing H2 molecules adsorbed on a transition-metal atom caused by the hydrogen-ammonia partial pressure difference. The H2 molecules bind to a transition-metal atom at H2 pressure- NH3 pressure-temperature 50atm-10-9atm-25°C , and they are released at 3atm-10-6atm-25°C . This process involves the same mechanism responsible for carbon monoxide poisoning of hemoglobin with the O2-CO partial pressure difference. We show that our findings can be applicable to an approach to induce hydrogen desorption on nanostructured hydrogen-storage materials without the need for increasing temperature.

  7. Health-Related Quality of Life in Elderly Patients With Pressure Ulcers in Different Care Settings.

    Science.gov (United States)

    Sebba Tosta de Souza, Diba Maria; Veiga, Daniela Francescato; Santos, Ivan Dunshee de Abranches Oliveira; Abla, Luiz Eduardo Felipe; Juliano, Yara; Ferreira, Lydia Masako

    2015-01-01

    The purpose of this study was to measure and compare health-related quality of life in elderly patients with pressure ulcers in different health care settings (home care acute care facility, and long-term care facility [LTCF]). Cross-sectional comparative study. One hundred ten elderly patients with (n = 36) and without (n = 74) pressure ulcers living in LTCFs, hospitals, or at home. The research setting included 1 tertiary and 2 community-based hospitals, 10 LTCFs, and 18 community health centers in Brazil. The Mini-Mental State Examination, Braden Scale for Predicting Pressure Sore Risk, and Medical Outcomes Study 36-Item Short Form Health Survey (SF-36) were used to assess cognitive status, pressure ulcer risk, and health-related quality of life, respectively. Compared with those without pressure ulcers, elderly patients with pressure ulcers reported significantly lower (worse) SF-36 scores on physical functioning (P ulcers scored significantly higher (better) SF-36 scores on mental health (P = .046) and vitality (P = .009). Hospitalized patients without pressure ulcers had lower SF-36 scores on bodily pain (P = .007) and general health (P = .026) than those living in LTCFs or at home. Patients without pressure ulcers in LTCFs had significantly lower Mini-Mental State Examination scores (lower cognitive status) than those living in other settings (P = .001). Elderly patients with pressure ulcers who were hospitalized and living at home or in LTCFs reported low scores on physical functioning and role physical, and LTCF residents also reported low scores on social functioning and role emotional. This shows the need for an environment that includes health care professionals prepared to implement strategies for pressure ulcer prevention.

  8. Analysis of wound filter performance from DREF yarn spun at different suction pressure

    Directory of Open Access Journals (Sweden)

    Pragnya S. Kanade

    2017-03-01

    Full Text Available Wound filters are quite popular in the domestic water purification systems. The performance of these filters is based on the distinctive yarn and winding variables. Yarn used for filtration application is normally produced on DREF spinning system. Several researchers have reported the influence of DREF spinning variables on yarn properties. However none of them are in context of filtration application. Since elucidation of influence of winding parameters on the filter performance has already been reported; it thus becomes intriguing to explore the influence of spinning suction pressure on filtration behavior. Yarn spun at different suction pressures was used to produce wound filter cartridges, keeping winding variables unchanged. Filters wound using yarn spun at higher spinning suction pressure resulted in greater pressure drop but showed better micron rating. However the pressure drop encountered also affects the retention capacity of the wound filter. The outcome of this study helps in establishing the relation between spinning suction pressure and performance parameters of wound filters. Design expert® software was used to develop regression equations to predict performance of wound filter for the given spinning suction pressure which is of practical significance for yarn and filter manufacturers, without performing filter test.

  9. Pressurized fast-pyrolysis characteristics of typical Chinese coals with different ranks

    Energy Technology Data Exchange (ETDEWEB)

    Chunyu Li; Jiantao Zhao; Yitian Fang; Yang Wang [Chinese Academy of Sciences, Taiyuan (China). Institute of Coal Chemistry

    2009-09-15

    The pressurized fast pyrolysis of three typical Chinese coals with different coal ranks (Huolinhe lignite, Shenmu bituminous coal, and Jincheng anthracite) was conducted on a self-made pressurized fixed-bed reactor. The physicochemical characteristics of the chars were studied via scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). In addition, thermogravimetric analysis (TGA) at ambient pressure has been used to study the influence of the residence time, the pyrolysis temperature, and pressure on the gasification reactivity of residual chars. The results show that the change in char yield and reactivity with pressure, at a residence time of 1 min, is different from that at longer residence time. This is related to the changing impacts of the rapid primary release of volatiles and the slower secondary cracking reactions of the evolved tars and the graphitization of the char structure. Furthermore, as the coal rank, pyrolysis pressure, temperature, and residence time increase, the surface structure of the char becomes much denser, the degree of graphitization is enhanced, and the number of the functional groups is reduced, which lead to the decrease in the gasification reactivity of the coal char. 23 refs., 1 figs., 2 tabs.

  10. A comparative sudy of two pressure relieving techniques on three different wheelchair cushions

    Directory of Open Access Journals (Sweden)

    C. Eksteen

    2006-02-01

    Full Text Available Introduction: Pressure relief done by a spinal cordinjured patient is of utmost importance in order to prevent pressuresore formation. Some pressure-relieving techniques are describedin previous literature, but their effectivity has not yet been deter-mined on different wheelchair cushions.Null Hypothesis (H0: The null hypothesis (H0 stated for thistudy is that there is no difference in the effectivity of forwardleaning and forward leaning towards the left as pressure relievingtechniques for quadriplegic wheelchair users over the differenwheelchair cushions.Design: An analytical experimental study design using a convenient sample group of ten complete lesion quadriplegics (C6 to T1 was performed at the Physiotherapy Department,University of Pretoria.Method: Interface pressure (in mmHg over the ischial tuberosities and upper thigh areas was measured using theTalley Oxford Pressure Monitor MKII with a 12-way matrix cell system.Results and Conclusion: The Friedman test for associated observations indicated statistically that the leaning  diagonally forward pressure relieving technique is more effective for all three wheelchair cushions used in this study.

  11. The difference in pediatric blood pressure between middle childhood and late childhood prior to dental treatment

    Directory of Open Access Journals (Sweden)

    Fitri Anissa Syaimima bt. Syaiful Azim

    2018-01-01

    Full Text Available Every child will go through several stages in his or her life. They are different from each other as they are in the process of development of cognition, physics, emotion, and personality. For many children, a visit to the dentist can raise their anxiety. This anxiousness will lead to stress that influences the cardiovascular function in the body. The purpose of this research was to determine the difference in pediatric blood pressure between middle childhood and late childhood prior to dental treatment. This research was a clinical trial, pure experimental study. The sample consisted of 30 children within the range of 4-12 years old where they were divided into two groups of age; middle childhood (4-7 years old and late childhood (8-12 years old. The blood pressures were measured before any dental treatment began and the values were recorded. The data were then analyzed using the One-Sample T-Test analysis. The results of blood pressure in middle childhood and late childhood were compared to the average mean values for each age group. It showed that there was a significant difference in the systolic pressure, which was found higher in the middle childhood group compared to the late childhood. From the result can be concluded that there was a difference in the pediatric blood pressure between middle childhood and late childhood prior to dental treatment.

  12. TECHNIQUES OF EVALUATION OF HEMOGLOBIN OXYGEN SATURATION IN CLINICAL OPHTHALMOLOGY

    Directory of Open Access Journals (Sweden)

    S. Yu. Petrov

    2016-01-01

    Full Text Available Oxygen content in body fluids and tissues is an important indicator of life support functions. A number of ocular pathologies, e.g. glaucoma, are of presumable vascular origin which means altered blood supply and oxygen circulation. Most oxygen is transported in the blood in the association with hemoglobin. When passing through the capillaries, hemoglobin releases oxygen, converting from oxygenated form to deoxygenated form. This process is accompanied by the changes in spectral characteristics of hemoglobin which result in different colors of arterial and venous blood. Photometric technique for the measurement of oxygen saturation in blood is based on the differences in light absorption by different forms of hemoglobin. The measurement of saturation is called oximetry. Pulse oximetry with assessment of tissue oxygenation is the most commonly used method in medicine. The degree of hemoglobin oxygen saturation in the eye blood vessels is the most accessible for noninvasive studies during ophthalmoscopy and informative. Numerous studies showed the importance of this parameter for the diagnosis of retinopathy of various genesis, metabolic status analysis in hyperglycemia, diagnosis and control of treatment of glaucoma and other diseases involving alterations in eye blood supply. The specific method for evaluation of oxygen concentration is the measurement of pressure of oxygen dissolved in the blood, i.e. partial pressure of oxygen. In ophthalmological practice, this parameter is measured in anterior chamber fluid evaluating oxygen level for several ophthalmopathies including different forms of glaucoma, for instillations of hypotensive eye drops as well as in vitreous body near to the optic disc under various levels of intraocular pressure. Currently, monitoring of oxygen saturation in retinal blood vessels, i.e. retinal oximetry, is well developed. This technique is based on the assessment of light absorption by blood depending on

  13. THE HABITABLE ZONE OF EARTH-LIKE PLANETS WITH DIFFERENT LEVELS OF ATMOSPHERIC PRESSURE

    Energy Technology Data Exchange (ETDEWEB)

    Vladilo, Giovanni; Murante, Giuseppe; Silva, Laura [INAF-Trieste Astronomical Observatory, Trieste (Italy); Provenzale, Antonello [Institute of Atmospheric Sciences and Climate-CNR, Torino (Italy); Ferri, Gaia; Ragazzini, Gregorio, E-mail: vladilo@oats.inaf.it [Department of Physics, University of Trieste, Trieste (Italy)

    2013-04-10

    As a contribution to the study of the habitability of extrasolar planets, we implemented a one-dimensional energy balance model (EBM), the simplest seasonal model of planetary climate, with new prescriptions for most physical quantities. Here we apply our EBM to investigate the surface habitability of planets with an Earth-like atmospheric composition but different levels of surface pressure. The habitability, defined as the mean fraction of the planet's surface on which liquid water could exist, is estimated from the pressure-dependent liquid water temperature range, taking into account seasonal and latitudinal variations of surface temperature. By running several thousands of EBM simulations we generated a map of the habitable zone (HZ) in the plane of the orbital semi-major axis, a, and surface pressure, p, for planets in circular orbits around a Sun-like star. As pressure increases, the HZ becomes broader, with an increase of 0.25 AU in its radial extent from p = 1/3 to 3 bar. At low pressure, the habitability is low and varies with a; at high pressure, the habitability is high and relatively constant inside the HZ. We interpret these results in terms of the pressure dependence of the greenhouse effect, the efficiency of horizontal heat transport, and the extent of the liquid water temperature range. Within the limits discussed in the paper, the results can be extended to planets in eccentric orbits around non-solar-type stars. The main characteristics of the pressure-dependent HZ are modestly affected by variations of planetary properties, particularly at high pressure.

  14. Tongue pressure modulation for initial gel consistency in a different oral strategy.

    Directory of Open Access Journals (Sweden)

    Sumiko Yokoyama

    Full Text Available In the recent hyper-aged societies of developed countries, the market for soft diets for patients with dysphagia has been growing and numerous jelly-type foods have become available. However, interrelationships between the biomechanics of oral strategies and jelly texture remain unclear. The present study investigated the influence of the initial consistency of jelly on tongue motor kinetics in different oral strategies by measuring tongue pressure against the hard palate.Jellies created as a mixture of deacylated gellan gum and psyllium seed gum with different initial consistencies (hard, medium or soft were prepared as test foods. Tongue pressure production while ingesting 5 ml of jelly using different oral strategies (Squeezing or Mastication was recorded in eight healthy volunteers using an ultra-thin sensor sheet system. Maximal magnitude, duration and total integrated values (tongue work of tongue pressure for size reduction and swallowing in each strategy were compared among initial consistencies of jelly, and between Squeezing and Mastication.In Squeezing, the tongue performed more work for size reduction with increasing initial consistency of jelly by modulating both the magnitude and duration of tongue pressure over a wide area of hard palate, but tongue work for swallowing increased at the posterior-median and circumferential parts by modulating only the magnitude of tongue pressure. Conversely, in Mastication, the tongue performed more work for size reduction with increasing initial consistency of jelly by modulating both magnitude and duration of tongue pressure mainly at the posterior part of the hard palate, but tongue work as well as other tongue pressure parameters for swallowing showed no differences by type of jelly.These results reveal fine modulations in tongue-palate contact according to the initial consistency of jelly and oral strategies.

  15. Comparison of plantar pressure distribution between three different shoes and three common movements in futsal.

    Science.gov (United States)

    Teymouri, Meghdad; Halabchi, Farzin; Mirshahi, Maryam; Mansournia, Mohammad Ali; Mousavi Ahranjani, Ali; Sadeghi, Amir

    2017-01-01

    Analysis of in-shoe pressure distribution during sport-specific movements may provide a clue to improve shoe design and prevent injuries. This study compared the mean and the peak pressures over the whole foot and ten separate areas of the foot, wearing different shoes during specific movements. Nine male adult recreational futsal players performed three trials of three sport-specific movements (shuffle, sprint and penalty kick), while they were wearing three brands of futsal shoes (Adidas, Lotto and Tiger). Plantar pressures on dominant feet were collected using the F-SCAN system. Peak and mean pressures for whole foot and each separate area were extracted. For statistical analysis, the mean differences in outcome variables between different shoes and movements were estimated using random-effects regression model using STATA ver.10. In the average calculation of the three movements, the peak pressure on the whole foot in Adidas shoe was less than Lotto [8.8% (CI95%: 4.1-13.6%)] and Tiger shoes [11.8% (CI95%:7-16.7%)], (P<0.001). Also, the recorded peak pressure on the whole foot in penalty kick was 61.1% (CI95%: 56.3-65.9%) and 57.6% (CI95%: 52.8-62.3%) less than Shuffle and Sprint tests, respectively (P<0.001). Areas with the highest peak pressure during all 3 movements were not different between all shoes. This area was medial forefoot in cases of shuffle and sprint movements and medial heel in case of penalty kick.

  16. Comparison of plantar pressure distribution between three different shoes and three common movements in futsal.

    Directory of Open Access Journals (Sweden)

    Meghdad Teymouri

    Full Text Available Analysis of in-shoe pressure distribution during sport-specific movements may provide a clue to improve shoe design and prevent injuries. This study compared the mean and the peak pressures over the whole foot and ten separate areas of the foot, wearing different shoes during specific movements.Nine male adult recreational futsal players performed three trials of three sport-specific movements (shuffle, sprint and penalty kick, while they were wearing three brands of futsal shoes (Adidas, Lotto and Tiger. Plantar pressures on dominant feet were collected using the F-SCAN system. Peak and mean pressures for whole foot and each separate area were extracted. For statistical analysis, the mean differences in outcome variables between different shoes and movements were estimated using random-effects regression model using STATA ver.10.In the average calculation of the three movements, the peak pressure on the whole foot in Adidas shoe was less than Lotto [8.8% (CI95%: 4.1-13.6%] and Tiger shoes [11.8% (CI95%:7-16.7%], (P<0.001. Also, the recorded peak pressure on the whole foot in penalty kick was 61.1% (CI95%: 56.3-65.9% and 57.6% (CI95%: 52.8-62.3% less than Shuffle and Sprint tests, respectively (P<0.001.Areas with the highest peak pressure during all 3 movements were not different between all shoes. This area was medial forefoot in cases of shuffle and sprint movements and medial heel in case of penalty kick.

  17. Evaluation of the impact of atmospheric pressure in different seasons on blood pressure in patients with arterial hypertension

    National Research Council Canada - National Science Library

    Kamiński, Marek; Cieślik-Guerra, Urszula I; Kotas, Rafał; Mazur, Piotr; Marańda, Witold; Piotrowicz, Maciej; Sakowicz, Bartosz; Napieralski, Andrzej; Trzos, Ewa; Uznańska-Loch, Barbara; Rechciński, Tomasz; Kurpesa, Małgorzata

    2016-01-01

    .... The main objective of our research was to assess the relationship between atmospheric pressure recorded with a frequency of 1 measurement per minute and the results of 24-h blood pressure monitoring...

  18. Diet and blood pressure: differences among whites, blacks and Hispanics in New York City 2010.

    Science.gov (United States)

    Bartley, Katherine; Jung, Molly; Yi, Stella

    2014-01-01

    Our study examined: 1) racial/ethnic differences in sodium and potassium intake; and 2) racial/ethnic differences in the relationship between dietary intake and blood pressure. Data were collected in New York City in 2010, and included a telephone health survey, a 24-hour urine collection and an in-home clinical exam. Linear regression was used to examine the association of sodium and potassium intakes with blood pressure separately by race/ethnicity, age and sex among 1568 participants. The results indicate large differences by population subgroup in: 1) nutrient intake, and 2) the relationship between sodium and potassium intake and blood pressure. Black and Hispanic males aged White counterparts. The regression results indicate a strong association between diet and blood pressure among Blacks and Hispanics only. Based on our assessment of the association of sodium and potassium intakes and blood pressure measurements, we find that young Black and Hispanic males aged diet quality and may be the most at risk for developing diet-related hypertension.

  19. Saturated Zone Colloid Transport

    Energy Technology Data Exchange (ETDEWEB)

    H. S. Viswanathan

    2004-10-07

    This scientific analysis provides retardation factors for colloids transporting in the saturated zone (SZ) and the unsaturated zone (UZ). These retardation factors represent the reversible chemical and physical filtration of colloids in the SZ. The value of the colloid retardation factor, R{sub col} is dependent on several factors, such as colloid size, colloid type, and geochemical conditions (e.g., pH, Eh, and ionic strength). These factors are folded into the distributions of R{sub col} that have been developed from field and experimental data collected under varying geochemical conditions with different colloid types and sizes. Attachment rate constants, k{sub att}, and detachment rate constants, k{sub det}, of colloids to the fracture surface have been measured for the fractured volcanics, and separate R{sub col} uncertainty distributions have been developed for attachment and detachment to clastic material and mineral grains in the alluvium. Radionuclides such as plutonium and americium sorb mostly (90 to 99 percent) irreversibly to colloids (BSC 2004 [DIRS 170025], Section 6.3.3.2). The colloid retardation factors developed in this analysis are needed to simulate the transport of radionuclides that are irreversibly sorbed onto colloids; this transport is discussed in the model report ''Site-Scale Saturated Zone Transport'' (BSC 2004 [DIRS 170036]). Although it is not exclusive to any particular radionuclide release scenario, this scientific analysis especially addresses those scenarios pertaining to evidence from waste-degradation experiments, which indicate that plutonium and americium may be irreversibly attached to colloids for the time scales of interest. A section of this report will also discuss the validity of using microspheres as analogs to colloids in some of the lab and field experiments used to obtain the colloid retardation factors. In addition, a small fraction of colloids travels with the groundwater without any significant

  20. Differing chemical compositions of three teas may explain their different effects on acute blood pressure in spontaneously hypertensive rats.

    Science.gov (United States)

    Li, Shan-Bing; Li, Yi-Fang; Mao, Zhong-Fu; Hu, Hui-Hua; Ouyang, Shu-Hua; Wu, Yan-Ping; Tsoi, Bun; Gong, Pin; Kurihara, Hiroshi; He, Rong-Rong

    2015-04-01

    Heavy tea consumption is suggested to be unsuitable for hypertensive people. However, the bioactive substances in different varieties of tea leaves are very different. This study compares the effects of three Chinese teas - C. sinensis, C. ptilophylla and C. assamica var. kucha - on blood pressure (BP) and heart rate in spontaneously hypertensive rats (SHRs). Intragastric administration of C. sinensis extract led to an acute increase in systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate in SHRs. However, C. ptilophylla and C. assamica var. kucha exerted no obvious influences on SBP, DBP or heart rate. Similar to the extract of C. sinensis, intragastric administration of caffeine also led to an acute increase in BP and heart rate in SHRs. In contrast, theobromine and theacrine - purine alkaloids predominantly contained in C. ptilophylla and C. assamica var. kucha, respectively - had no pressor effects. The effect of caffeine on BP was related to the regulation of plasma epinephrine and norepinephrine levels in SHRs. The different effects of C. sinensis, C. ptilophylla and C. assamica var. kucha on BP might be explained, at least partially, by the differences in the varieties and contents of purine alkaloids. © 2014 Society of Chemical Industry.

  1. Association between general and abdominal obesity with high blood pressure: difference between genders.

    Science.gov (United States)

    Silva, Alison O; Silva, Micaelly V; Pereira, Lisley K N; Feitosa, Wallacy M N; Ritti-Dias, Raphael M; Diniz, Paula R B; Oliveira, Luciano M F T

    2016-01-01

    To assess the association between general and abdominal obesity with high blood pressure in adolescents of both genders from the public school system. This was an epidemiological, descriptive, exploratory study, with a quantitative approach and local scope whose sample consisted of 481 high school students (aged 14-19), selected by using a random cluster sampling strategy. Blood pressure was measured through the use of automated monitor and was considered high when the pressure values were at or above the 95th percentile. The analyses were performed using the chi-squared test and binary logistic regression. The prevalence of high blood pressure was 6.4%, and it was higher among boys (9.0% vs. 4.7%, p<0.05). There was no significant difference between general (p=0.903) and abdominal obesity (p=0.157) when genders were compared. After adjusting for age, high blood pressure was associated with general (OR=6.4; p<0.001) and abdominal obesity (OR=7.0; p<0.001) only among boys, when comparing the fourth quartile with the first quartile of body mass index (≤ 18.6 kg/m(2)vs. ≥ 23.5 kg/m(2)) and waist circumference (≤ 69 cm vs. ≥ 80.1cm). It was observed that general and abdominal obesity are associated with high blood pressure only in boys, regardless of age. Copyright © 2015 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

  2. Effects on measurement of photon-atom scattering of applied pressures on sample at different thickness

    Energy Technology Data Exchange (ETDEWEB)

    Icelli, Orhan [Department of Physics Education, Education Faculty of Erzincan, Atatuerk University, Erzincan (Turkey)]. E-mail: orhan_icelli@hotmail.com; Erzeneoglu, Salih [Department of Physics, Faculty of Sciences, Atatuerk University, Erzurum (Turkey)

    2006-01-15

    N{sub coh}/N{sub Comp} and NK{sub {beta}}/NK{sub {alpha}} intensity ratios of scattered photons by Zn in the linear region and the infinite mass thickness region are measured as functions of the pressure used for compressing the pellets with a Si(Li) detector using Am-241 and Fe-55 annular source. Besides, the effect on the experimental intensity ratio of relation between two different thicknesses of sample with applied different pressures on the sample is investigated in this study. Harmony between the linear and infinitive (critical) thickness region and the applied pressure on the sample has directly affected the experimental intensity ratios. Experimental results were not compared with various theoretical values in the literature, for present results constitute the first experimental measurements.

  3. Differences in transmural pressure and axial loading ex vivo affect arterial remodeling and material properties.

    Science.gov (United States)

    Lawrence, Amanda R; Gooch, Keith J

    2009-10-01

    Arterial axial strains, present in the in vivo environment, often become reduced due to either bypass grafting or the normal aging process. Since the prevalence of hypertension increases with aging, arteries are often exposed to both decreased axial stretch and increased transmural pressure. The combined effects of these mechanical stimuli on the mechanical properties of vessels have not previously been determined. Porcine carotid arteries were cultured for 9 days at normal and reduced axial stretch ratios in the presence of normotensive and hypertensive transmural pressures using ex vivo perfusion techniques. Measurements of the amount of axial stress were obtained through longitudinal tension tests while inflation-deflation test results were used to determine circumferential stresses and incremental moduli. Macroscopic changes in artery geometry and zero-stress state opening angles were measured. Arteries cultured ex vivo remodeled in response to the mechanical environment, resulting in changes in arterial dimensions of up to approximately 25% and changes in zero-stress opening angles of up to approximately 55 degrees . While pressure primarily affected circumferential remodeling and axial stretch primarily affected axial remodeling, there were clear examples of interactions between these mechanical stimuli. Culture with hypertensive pressure, especially when coupled with reduced axial loading, resulted in a rightward shift in the pressure-diameter relationship relative to arteries cultured with normotensive pressure. The observed differences in the pressure-diameter curves for cultured arteries were due to changes in artery geometry and, in some cases, changes in the arteries' intrinsic mechanical properties. Relative to freshly isolated arteries, arteries cultured under mechanical conditions similar to in vivo conditions were stiffer, suggesting that aspects of the ex vivo culture other than the mechanical environment also influenced changes in the arteries

  4. Ethnic Differences in Physical Fitness, Blood Pressure and Blood Chemistry in Women (AGES 20-63)

    Science.gov (United States)

    Ayers, G. W.; Wier, L. T.; Jackson, A. S.; Stuteville, J. E.; Keptra, Sean (Technical Monitor)

    1999-01-01

    This study examined the role of ethnicity on the aerobic fitness, blood pressure, and selected blood chemistry values of women. One hundred twenty-four females (mean age 41.37 +/- 9.0) were medically Examined at the NASA/Johnson Space Center occupational health clinic. Ethnic groups consisted of 23 Black (B), 18 Hispanic (H) and 83 Non-minority (NM). Each woman had a maximum Bruce treadmill stress test (RER greater than or = 1.1) and a negative ECG. Indirect calorimetry, skinfolds, self-report physical activity (NASA activity scale), seated blood pressure, and blood chemistry panel determined VO2max, percent fat, level of physical activity, blood pressure and blood chemistry values. ANOVA revealed that the groups did not differ (p greater than 0.05) in age, VO2 max, weight, percent fat, level of physical activity, total cholesterol, or HDL-C. However, significant differences (p greater than 0.05) were noted in BMI, diastolic blood pressure, and blood chemistries. BMI was 3.17 higher in H than in NM; resting diastolic pressures were 5.69 and 8.05 mmHg. lower in NM and H than in B; triglycerides were 48.07 and 37.21 mg/dl higher in H than in B and NM; hemoglobin was .814 gm/dl higher in NM than B; fasting blood sugar was 15.41 mg/dl higher in H than NM; The results of this study showed that ethnic groups differed in blood pressure and blood chemistry values but not aerobic fitness or physical activity. There was an ethnic difference in BMI but not percent fat.

  5. Ignition and combustion characteristics of molded amorphous boron under different oxygen pressures

    Science.gov (United States)

    Liang, Daolun; Liu, Jianzhong; Zhou, Yunan; Zhou, Junhu; Cen, Kefa

    2017-09-01

    Ignition and combustion characteristics of amorphous boron (B) have received much attention from researchers in recent decades. A pressurized concentrated ignition experimental system was designed to evaluate the ignition and combustion characteristics of molded B samples. The ignition experiments were carried out under different oxygen pressures (1-9 atm). The condensed combustion products were then analyzed using a scanning electron microscope, an X-ray energy dispersive spectrometer, and an X-ray diffractometer. Furthermore, the complete oxidation rates of the samples were detected by inductively coupled plasma chromatography. As the oxygen pressure increased, the combustion intensity of the samples steadily increased, and the ignition delay time and combustion time both decreased. Under the oxygen pressure of 9 atm, the average ignition delay time and combustion time were 2640 ms and 2596 ms, respectively, and the highest combustion temperature reached 1561.5 °C. The initial diffusion flame on the sample surface was green and the brightest, which was produced by an intermediate combustion product, BO2 (corresponding molecular emission spectrum wavelength, 547.3 nm). Emission spectra of another intermediate product, BO (431.9 nm) was also detected. Two different types of structures were found in the condensed combustion products of the samples. The first type was the flaky B2O3 structure, and the second type was the flocculent structure of incomplete combustion products. The B2O3 content in the condensed combustion products increased with the oxygen pressure during combustion. The complete oxidation ratio of the samples also increased with the oxygen pressure, and reached the maximum value of 68.71% under 9 atm. Overall, the samples showed better ignition and combustion characteristics under higher oxygen pressure.

  6. Association between body size and blood pressure in children from different ethnic origins

    Directory of Open Access Journals (Sweden)

    LA de Hoog Marieke

    2012-11-01

    Full Text Available Abstract Objective To assess associations between body size and blood pressure in children (5-6 years from different ethnic origins. Method Five ethnic groups of the ABCD cohort were examined: Dutch (n=1 923, Turkish (n=99, Moroccan (n=187, Black-African (n=67 and Black-Caribbean (n=121. Data on body-mass-index (BMI, waist-to-height ratio (WHtR, fat-mass-index (FMI, and systolic blood pressure (SBP and diastolic blood pressure (DBP, were collected. Linear regression analysis with restricted cubic splines was used to examine non-linear associations between body size and blood pressure, adjusted for age, sex, height and birth weight. Results Ethnic differences were found in associations of BMI with SBP and DBP (SBP: p=0.001 and DBP: p=0.01 and FMI with SBP (p=0.03. BMI and FMI had a relatively large positive association with SBP in Turkish children (BMI: β=2.46mmHg; 95%CI:1.20-3.72; FMI: β=2.41mmHg; 95%CI:1.09-3.73 compared to Dutch (BMI: β=1.31mmHg; 95%CI:0.71-1.92; FMI: β=0.84mmHg; 95%CI:0.23-1.45. Black-Caribbean and Moroccan children showed high blood pressure with low BMI and FMI. Moroccan children showed higher SBP with high BMI and FMI. WHtR was positively associated with SBP and DBP, similar in all ethnic groups. Generally, strongest associations with blood pressure were found for BMI in all ethnic groups. Conclusion Ethnic-specific associations between BMI, and FMI and blood pressure are present at young age, with Turkish children showing the highest increase in blood pressure with increasing body size. The higher blood pressure in the Black-Caribbean and Moroccan children with low BMI needs further research. WHtR or FMI do not seem to be associated more strongly to blood pressure than BMI in any ethnic group.

  7. Storm pulse chemographs of saturation index and carbon dioxide pressure: implications for shifting recharge sources during storm events in the karst aquifer at Fort Campbell, Kentucky/Tennessee, USA

    Science.gov (United States)

    Vesper, Dorothy J.; White, William B.

    Continuous records of discharge, specific conductance, and temperature were collected through a series of storm pulses on two limestone springs at Fort Campbell, western Kentucky/Tennessee, USA. Water samples, collected at short time intervals across the same storm pulses, were analyzed for calcium, magnesium, bicarbonate, total organic carbon, and pH. Chemographs of calcium, calcite saturation index, and carbon dioxide partial pressure were superimposed on the storm hydrographs. Calcium concentration and specific conductance track together and dip to a minimum either coincident with the peak of the hydrograph or lag slightly behind it. The CO2 pressure continues to rise on the recession limb of the hydrograph and, as a result, the saturation index decreases on the recession limb of the hydrograph. These results are interpreted as being due to dispersed infiltration through CO2-rich soils lagging the arrival of quickflow from sinkhole recharge in the transport of storm flow to the springs. Karst spring hydrographs reflect not only the changing mix of base flow and storm flow but also a shift in source of recharge water over the course of the storm. L'enregistrement en continu du débit, de la conductivité et de la température de l'eau a été réalisé au cours d'une série de crues à deux sources émergeant de calcaires, à Fort Campbell (Kentucky occidental, Tennessee, États-Unis). Des échantillons d'eau, prélevés à de courts pas de temps lors de ces crues, ont été analysés pour le calcium, le magnésium, les bicarbonates, le carbone organique total et le pH. Les chimiogrammes de calcium, d'indice de saturation de la calcite et de la pression partielle en CO2 ont été superposés aux hydrogrammes de crue. La concentration en calcium et la conductivité de l'eau se suivent bien et passent par un minimum correspondant au pic de l'hydrogramme ou légèrement retardé. La pression partielle en CO2 continue de croître au cours de la récession de l

  8. Differences in blood pressure by measurement technique in neurocritically ill patients: A technological assessment.

    Science.gov (United States)

    Lele, Abhijit V; Wilson, Daren; Chalise, Prabhakar; Nazzaro, Jules; Krishnamoorthy, Vijay; Vavilala, Monica S

    2018-01-01

    Blood pressure data may vary by measurement technique. We performed a technological assessment of differences in blood pressure measurement between non-invasive blood pressure (NIBP) and invasive arterial blood pressure (ABP) in neurocritically ill patients. After IRB approval, a prospective observational study was performed to study differences in systolic blood pressure (SBP), mean arterial pressure (MAP), and cerebral perfusion pressure (CPP) values measured by NIBP arm, ABP at level of the phlebostatic axis (ABP heart) and ABP at level of the external auditory meatus (ABP brain) at 30 and 45-degree head of bed elevation (HOB) using repeated measure analysis of covariance and correlation coefficients. Overall, 168 patients were studied with median age of 57 ± 15 years, were mostly female (57%), with body mass index ≤30 (66%). Twenty-three percent (n = 39) had indwelling intracranial pressure monitors, and 19.7% (n = 33) received vasoactive agents. ABP heart overestimated ABP brain for SBP (11.5 ± 2.7 mmHg, p < .001), MAP (mean difference 13.3 ± 0.5 mmHg, p < .001) and CPP (13.4 ± 3.2 mmHg, p < .001). ABP heart overestimated NIBP arm for SBP (8 ± 1.5 mmHg, p < .001), MAP (mean difference 8.6 ± 0.8 mmHg, p < .001), and CPP (mean difference 9.8 ± 3.2 mmHg, p < .001). Regardless of HOB elevation, ABP heart overestimates MAP compared to ABP brain and NIBP arm. Using ABP heart data overestimates CPP and may be responsible for not achieving SBP, MAP or CPP targets aimed at the brain. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Arterial pressure-based cardiac output in septic patients: different accuracy of pulse contour and uncalibrated pressure waveform devices.

    Science.gov (United States)

    Monnet, Xavier; Anguel, Nadia; Naudin, Brice; Jabot, Julien; Richard, Christian; Teboul, Jean-Louis

    2010-01-01

    We compared the ability of two devices estimating cardiac output from arterial pressure-curve analysis to track the changes in cardiac output measured with transpulmonary thermodilution induced by volume expansion and norepinephrine in sepsis patients. In 80 patients with septic circulatory failure, we administered volume expansion (40 patients) or introduced/increased norepinephrine (40 patients). We measured the pulse contour-derived cardiac index (CI) provided by the PiCCO device (CIpc), the arterial pressure waveform-derived CI provided by the Vigileo device (CIpw), and the transpulmonary thermodilution CI (CItd) before and after therapeutic interventions. The changes in CIpc accurately tracked the changes in CItd induced by volume expansion (bias, -0.20 +/- 0.63 L/min/m2) as well as by norepinephrine (bias, -0.05 +/- 0.74 L/min/m2). The changes in CIpc accurately detected an increase in CItd >or= 15% induced by volume expansion and norepinephrine introduction/increase (area under ROC curves, 0.878 (0.736 to 0.960) and 0.924 (0.795 to 0.983), respectively; P or= 15% induced by volume expansion and norepinephrine introduction/increase (area under ROC curves, 0.564 (0.398 to 0.720) and 0.541 (0.377 to 0.700, respectively, both not significantly different from versus 0.500). The CIpc was reliable and accurate for assessing the CI changes induced by volume expansion and norepinephrine. By contrast, the CIpw poorly tracked the trends in CI induced by those therapeutic interventions.

  10. Compositional Differences of Ojeok-san (Wuji-san Decoctions Using Pressurized or Non-pressurized Methods for Variable Extraction Times

    Directory of Open Access Journals (Sweden)

    Kim Jung-Hoon

    2012-06-01

    Full Text Available This study compared Ojeok-san (Wuji-san in Chinese decoctions produced using different extraction methods for variable times. Decoctions were extracted in pressurized or non-pressurized conditions for 60, 120, and 180 mins. We investigated the Ojeok-san extract yield, the total soluble solid content, the hydrogen ion concentration (pH, and the reference compound content. The extract yield and the total soluble solid content were higher in decoctions produced by non-pressurized extraction; both were proportional to the extraction time. The pH tended to decrease as the extraction time was increased in decoctions produced using both methods. After 60 and 180 mins, the levels of albiflorin, paeoniflorin, nodakenin, naringin, and neohesperidin were significantly higher in decoctions extracted using the non-pressurized method compared with those extracted using the pressurized method. After 120 mins, only cinnamaldehyde was extracted in a greater amount in pressurized decoctions compared with non-pressurized decoctions. The levels of paeoniflorin, ferulic acid, nodakenin, naringin, hesperidin, neohesperidin, and glycyrrhizin increased with time in non-pressurized decoctions. This study showed that the use of pressurized and non-pressurized extraction methods for different times affected the composition of Ojeoksan (Wuji-san decoctions.

  11. Compositional Differences of Ojeok-san (Wuji-san) Decoctions Using Pressurized or Non-pressurized Methods for Variable Extraction Times.

    Science.gov (United States)

    Kim, Jung-Hoon; Seo, Chang-Seob; Kim, Seong-Sil; Shin, Hyeun-Kyoo

    2012-06-01

    This study compared Ojeok-san (Wuji-san in Chinese) decoctions produced using different extraction methods for variable times. Decoctions were extracted in pressurized or non-pressurized conditions for 60, 120, and 180 mins. We investigated the Ojeok-san extract yield, the total soluble solid content, the hydrogen ion concentration (pH), and the reference compound content. The extract yield and the total soluble solid content were higher in decoctions produced by non-pressurized extraction; both were proportional to the extraction time. The pH tended to decrease as the extraction time was increased in decoctions produced using both methods. After 60 and 180 mins, the levels of albiflorin, paeoniflorin, nodakenin, naringin, and neohesperidin were significantly higher in decoctions extracted using the non-pressurized method compared with those extracted using the pressurized method. After 120 mins, only cinnamaldehyde was extracted in a greater amount in pressurized decoctions compared with non-pressurized decoctions. The levels of paeoniflorin, ferulic acid, nodakenin, naringin, hesperidin, neohesperidin, and glycyrrhizin increased with time in non-pressurized decoctions. This study showed that the use of pressurized and non-pressurized extraction methods for different times affected the composition of Ojeoksan (Wuji-san) decoctions.

  12. Compositional Differences of Ojeok-san (Wuji-san) Decoctions Using Pressurized or Non-pressurized Methods for Variable Extraction Times

    OpenAIRE

    Kim Jung-Hoon; Seo Chang-Seob; Kim Seong-Sil; Shin Hyeun-Kyoo

    2012-01-01

    This study compared Ojeok-san (Wuji-san in Chinese) decoctions produced using different extraction methods for variable times. Decoctions were extracted in pressurized or non-pressurized conditions for 60, 120, and 180 mins. We investigated the Ojeok-san extract yield, the total soluble solid content, the hydrogen ion concentration (pH), and the reference compound content. The extract yield and the total soluble solid content were higher in decoctions produced by non-pressurized extraction; b...

  13. Seven-day mortality can be predicted in medical patients by blood pressure, age, respiratory rate, loss of independence, and peripheral oxygen saturation (the PARIS score: a prospective cohort study with external validation.

    Directory of Open Access Journals (Sweden)

    Mikkel Brabrand

    Full Text Available Most existing risk stratification systems predicting mortality in emergency departments or admission units are complex in clinical use or have not been validated to a level where use is considered appropriate. We aimed to develop and validate a simple system that predicts seven-day mortality of acutely admitted medical patients using routinely collected variables obtained within the first minutes after arrival.This observational prospective cohort study used three independent cohorts at the medical admission units at a regional teaching hospital and a tertiary university hospital and included all adult (≥ 15 years patients. Multivariable logistic regression analysis was used to identify the clinical variables that best predicted the endpoint. From this, we developed a simplified model that can be calculated without specialized tools or loss of predictive ability. The outcome was defined as seven-day all-cause mortality. 76 patients (2.5% met the endpoint in the development cohort, 57 (2.0% in the first validation cohort, and 111 (4.3% in the second. Systolic blood Pressure, Age, Respiratory rate, loss of Independence, and peripheral oxygen Saturation were associated with the endpoint (full model. Based on this, we developed a simple score (range 0-5, ie, the PARIS score, by dichotomizing the variables. The ability to identify patients at increased risk (discriminatory power and calibration was excellent for all three cohorts using both models. For patients with a PARIS score ≥ 3, sensitivity was 62.5-74.0%, specificity 85.9-91.1%, positive predictive value 11.2-17.5%, and negative predictive value 98.3-99.3%. Patients with a score ≤ 1 had a low mortality (≤ 1%; with 2, intermediate mortality (2-5%; and ≥ 3, high mortality (≥ 10%.Seven-day mortality can be predicted upon admission with high sensitivity and specificity and excellent negative predictive values.

  14. Clinic Versus Daytime Ambulatory Blood Pressure Difference in Hypertensive Patients: The Impact of Age and Clinic Blood Pressure.

    Science.gov (United States)

    Banegas, José R; Ruilope, Luis M; de la Sierra, Alejandro; Vinyoles, Ernest; Gorostidi, Manuel; de la Cruz, Juan J; Segura, Julián; Oliveras, Anna; Martell, Nieves; García-Puig, Juan; Williams, Bryan

    2017-02-01

    Clinic blood pressure (BP) is usually higher than daytime ambulatory BP in hypertensive patients, but some recent studies have challenged this view, suggesting that this relationship is strongly influenced by age. We used the Spanish ambulatory BP monitoring cohort to examine differences between clinic and daytime BP by age among 104 639 adult hypertensive patients (office systolic/diastolic BP ≥140/90 mm Hg or treated) in usual primary-care practice, across the wide age spectrum. To assess the impact of age, cardiovascular variables, and clinic BP on the clinic-daytime BP differences, we built multivariable regression models of the average BP differences, white-coat hypertension (high clinic BP and normal daytime BP), and masked hypertension (normal clinic BP and high daytime BP). In most patients, mean clinic BP values were higher than daytime BP at all ages. Some 36.7% of patients had white-coat hypertension (amounting to 50% at clinic systolic BP of 140-159 mm Hg) and 3.9% had masked hypertension (amounting to 18% at clinic systolic BP of 130-139 mm Hg). Age explained 0.1% to 1.7% of the variance of quantitative or categorical BP differences (Phypertension status in >40% of patients. This misclassification was not importantly influenced by age but was more evident in patients with borderline/grade 1 hypertension. These findings reinforce the importance of ambulatory BP monitoring for defining BP status in routine clinical practice. © 2017 American Heart Association, Inc.

  15. The effects of blood pressure reduction and of different blood pressure-lowering regimens on major cardiovascular events according to baseline blood pressure : meta-analysis of randomized trials

    NARCIS (Netherlands)

    Czernichow, Sebastien; Zanchetti, Alberto; Turnbull, Fiona; Barzi, Federica; Ninomiya, Toshiaru; Kengne, Andre-Pascal; Lambers Heerspink, Hiddo J.; Perkovic, Vlado; Huxley, Rachel; Arima, Hisatomi; Patel, Anushka; Chalmers, John; Woodward, Mark; MacMahon, Stephen; Neal, Bruce

    Background The benefits of reducing blood pressure are well established, but there remains uncertainty about whether the magnitude of the effect varies with the initial blood pressure level. The objective was to compare the risk reductions achieved by different blood pressure-lowering regimens among

  16. The Difference in Translaminar Pressure Gradient and Neuroretinal Rim Area in Glaucoma and Healthy Subjects

    Directory of Open Access Journals (Sweden)

    Lina Siaudvytyte

    2014-01-01

    Full Text Available Purpose. To assess differences in translaminar pressure gradient (TPG and neuroretinal rim area (NRA in patients with normal tension glaucoma (NTG, high tension glaucoma (HTG, and healthy controls. Methods. 27 patients with NTG, HTG, and healthy controls were included in the prospective pilot study (each group consisted of 9 patients. Intraocular pressure (IOP, intracranial pressure (ICP, and confocal laser scanning tomography were assessed. TPG was calculated as the difference of IOP minus ICP. ICP was measured using noninvasive two-depth transcranial Doppler device. The level of significance P 0.05. The difference between TPG for healthy (5.4(7.7 mmHg and glaucomatous eyes (NTG 6.3(3.1 mmHg, HTG 15.7(7.7 mmHg was statistically significant (P < 0.001. Higher TPG was correlated with decreased NRA (r = −0.83; P = 0.01 in the NTG group. Conclusion. Translaminar pressure gradient was higher in glaucoma patients. Reduction of NRA was related to higher TPG in NTG patients. Further prospective studies are warranted to investigate the involvement of TPG in glaucoma management.

  17. Drilling Performance of Rock Drill by High-Pressure Water Jet under Different Configuration Modes

    Directory of Open Access Journals (Sweden)

    Songyong Liu

    2017-01-01

    Full Text Available In the rock drilling progress, the resistant force results in tools failure and the low drilling efficiency; thus, it is necessary to reduce the tools failure and enhance the drilling efficiency. In this paper, different configuration modes of drilling performance assisted with water jet are explored based on the mechanism and experiment analysis of rock drilling assisted with water jet. Moreover, the rotary sealing device with high pressure is designed to achieve the axial and rotation movement simultaneously as well as good sealing effect under high-pressure water jet. The results indicate that the NDB and NFB have better effects on drilling performance compared with that of NSB. Moreover, the high-pressure water jet is helpful not only to reduce the drill rod deflection, but also to reduce the probability of drill rod bending and improve the drill rod service life.

  18. Different alternative splicing patterns are subject to opposite selection pressure for protein reading frame preservation

    Directory of Open Access Journals (Sweden)

    Chuang Trees-Juen

    2007-09-01

    Full Text Available Abstract Background Alternative splicing (AS has been regarded capable of altering selection pressure on protein subsequences. Particularly, the frequency of reading frame preservation (FRFP, as a measure of selection pressure, has been reported to be higher in alternatively spliced exons (ASEs than in constitutively spliced exons (CSEs. However, recently it has been reported that different ASE types – simple and complex ASEs – may be subject to opposite selection forces. Therefore, it is necessary to re-evaluate the evolutionary effects of such splicing patterns on frame preservation. Results Here we show that simple and complex ASEs, respectively, have higher and lower FRFPs than CSEs. Since complex ASEs may alter the ends of their flanking exons, the selection pressure on frame preservation is likely relaxed in this ASE type. Furthermore, conservation of the ASE/CSE splicing pattern increases the FRFPs of simple ASEs but decreases those of complex ASEs. Contrary to the well-recognized concept of strong selection pressure on conserved ASEs for protein reading frame preservation, our results show that conserved complex ASEs are relaxed from such pressure and the frame-disrupting effect caused by the insertion of complex ASEs can be offset by compensatory changes in their flanking exons. Conclusion In this study, we find that simple and complex ASEs undergo opposite selection pressure for protein reading frame preservation, with CSEs in-between. Simple ASEs have much higher FRFPs than complex ones. We further find that the FRFPs of complex ASEs coupled with flanking exons are close to those of simple ASEs, indicating that neighboring exons of an ASE may evolve in a coordinated way to avoid protein dysfunction. Therefore, we suggest that evolutionary analyses of AS should take into consideration the effects of different splicing patterns and the joint effects of multiple AS events.

  19. Cleaning efficacy of an apical negative-pressure irrigation system at different exposure times.

    Science.gov (United States)

    Heilborn, Carlos; Reynolds, Kai; Johnson, James D; Cohenca, Nestor

    2010-10-01

    Recent studies have shown that the apical negative-pressure irrigation system EndoVac (Discus Dental) produces better disinfection and cleanliness at the apical third of root canals than current irrigation methods using positive pressure. The aim of this histologic study was to compare the EndoVac system at two different exposure times to the traditional positive-pressure irrigation technique for root canal cleaning efficacy and to measure the volume of irrigation at the apical third. Fifty extracted human incisors, canines, and premolars (with one canal) were used. All teeth were stored in sterile saline and then randomly assigned to one of three experimental groups of 15 each. All teeth were cleaned and shaped at working length using Profile Series 29 (Dentsply Tulsa) to a size 6 (ISO size 36) or larger depending on the first instrument to bind at the apical third. After working length was reached with the master apical file, apical irrigation was accomplished with 6% sodium hypochlorite (NaOCl) over a predetermined time for each group as follows: group 1, EndoVac for 210 seconds; group 2, EndoVac for 150 seconds; group 3, traditional positive-pressure irrigation for 210 seconds. The amount of debris left in the canals was quantified at 1 and 3 mm from working length. No statistical differences were found at 3 mm from working length. At 1 mm from working length, an overall test of association was significant when comparing across the three groups (P = .03). The apical negative-pressure irrigation system EndoVac has the potential to achieve significantly better root canal cleaning at the apical third of root canals and in less exposure time than required with traditional positive-pressure irrigation.

  20. Evaluation of Different Dose-Response Models for High Hydrostatic Pressure Inactivation of Microorganisms

    Science.gov (United States)

    2017-01-01

    Modeling of microbial inactivation by high hydrostatic pressure (HHP) requires a plot of the log microbial count or survival ratio versus time data under a constant pressure and temperature. However, at low pressure and temperature values, very long holding times are needed to obtain measurable inactivation. Since the time has a significant effect on the cost of HHP processing it may be reasonable to fix the time at an appropriate value and quantify the inactivation with respect to pressure. Such a plot is called dose-response curve and it may be more beneficial than the traditional inactivation modeling since short holding times with different pressure values can be selected and used for the modeling of HHP inactivation. For this purpose, 49 dose-response curves (with at least 4 log10 reduction and ≥5 data points including the atmospheric pressure value (P = 0.1 MPa), and with holding time ≤10 min) for HHP inactivation of microorganisms obtained from published studies were fitted with four different models, namely the Discrete model, Shoulder model, Fermi equation, and Weibull model, and the pressure value needed for 5 log10 (P5) inactivation was calculated for all the models above. The Shoulder model and Fermi equation produced exactly the same parameter and P5 values, while the Discrete model produced similar or sometimes the exact same parameter values as the Fermi equation. The Weibull model produced the worst fit (had the lowest adjusted determination coefficient (R2adj) and highest mean square error (MSE) values), while the Fermi equation had the best fit (the highest R2adj and lowest MSE values). Parameters of the models and also P5 values of each model can be useful for the further experimental design of HHP processing and also for the comparison of the pressure resistance of different microorganisms. Further experiments can be done to verify the P5 values at given conditions. The procedure given in this study can also be extended for enzyme

  1. Evaluation of Different Dose-Response Models for High Hydrostatic Pressure Inactivation of Microorganisms

    Directory of Open Access Journals (Sweden)

    Sencer Buzrul

    2017-09-01

    Full Text Available Modeling of microbial inactivation by high hydrostatic pressure (HHP requires a plot of the log microbial count or survival ratio versus time data under a constant pressure and temperature. However, at low pressure and temperature values, very long holding times are needed to obtain measurable inactivation. Since the time has a significant effect on the cost of HHP processing it may be reasonable to fix the time at an appropriate value and quantify the inactivation with respect to pressure. Such a plot is called dose-response curve and it may be more beneficial than the traditional inactivation modeling since short holding times with different pressure values can be selected and used for the modeling of HHP inactivation. For this purpose, 49 dose-response curves (with at least 4 log10 reduction and ≥5 data points including the atmospheric pressure value (P = 0.1 MPa, and with holding time ≤10 min for HHP inactivation of microorganisms obtained from published studies were fitted with four different models, namely the Discrete model, Shoulder model, Fermi equation, and Weibull model, and the pressure value needed for 5 log10 (P5 inactivation was calculated for all the models above. The Shoulder model and Fermi equation produced exactly the same parameter and P5 values, while the Discrete model produced similar or sometimes the exact same parameter values as the Fermi equation. The Weibull model produced the worst fit (had the lowest adjusted determination coefficient (R2adj and highest mean square error (MSE values, while the Fermi equation had the best fit (the highest R2adj and lowest MSE values. Parameters of the models and also P5 values of each model can be useful for the further experimental design of HHP processing and also for the comparison of the pressure resistance of different microorganisms. Further experiments can be done to verify the P5 values at given conditions. The procedure given in this study can also be extended for

  2. Pressure distribution under three different types of harnesses used for guide dogs.

    Science.gov (United States)

    Peham, C; Limbeck, S; Galla, K; Bockstahler, B

    2013-12-01

    The aim of this study was to evaluate the pressure distribution under three different types of harnesses used for guide dogs (designated H1, H2 and H3). The dogs (n = 8) led a trainer through a course including a range of exercises (straight line, curve left, curve right, upstairs and downstairs). All dogs were clinically sound and showed no sign of lameness. The pressures beneath the harnesses were determined by sensor strips and related to the gait. In all harnesses, the highest pressures were found in the right sternal region (H1 2.02 ± 0.6N/cm(2); H2 1.76 ± 0.4N/cm(2); H3 1.14 ± 0.5 N/cm(2)). In all other regions, the pressures were in the range of 0-1.32 N/cm(2). The right and left sternal regions were almost constantly loaded. Contrary to previous assumptions, the back regions had minimal loading. This investigation demonstrated that there were significant differences among the harnesses. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Evaluation of an indirect oscillometric blood pressure monitor in anaesthetised dogs at three different anatomical locations.

    Science.gov (United States)

    Fujiyama, M; Sano, H; Chambers, J P; Gieseg, M

    2017-07-01

    To evaluate the agreement between invasive and non-invasive measurements of blood pressure (BP) using an oscillometer (PetTrust) at three different anatomical locations in anaesthetised dogs under different haemodynamic conditions. Eight adult Greyhounds weighing 23.5-36.5 kg were anaesthetised with isoflurane and positioned in dorsal recumbency. Systolic arterial pressure (SAP), diastolic arterial pressure (DAP) and mean arterial pressure (MAP) were measured invasively via a dorsal pedal artery and non-invasively using the oscillometer with cuffs placed above the carpus, above the tarsus and around the tail base. Phenylephrine was administered to induce vasoconstriction, dobutamine was used to increase cardiac output and increased end-tidal concentrations of isoflurane were used to induce vasodilation. Correlation between measurements was analysed by linear regression and agreement was analysed using Bland-Altman plots. Seventy two representative measurements were obtained. Mean differences (bias) between invasive and non-invasive measurements were 0.9 except for SAP on the pelvic limb and DAP on the tail. More than 50 and 80% of values measured using oscillometry lay within 10 and 20 mmHg, respectively, of values measured invasively except for SAP on the tail. SAP tended to be overestimated when measured non-invasively at low BP, and be underestimated at high BP. DAP was underestimated during low BP and overestimated during high BP. Hypotension (MAP invasive measurement of MAP at all locations. MAP is the driving pressure for tissue perfusion, thus MAP measurement is clinically essential. This oscillometric device yields reliable MAP measurements at three anatomical locations over a wide range of BP and can identify hypotension with high sensitivity and specificity.

  4. Venous oxygen saturation.

    Science.gov (United States)

    Hartog, Christiane; Bloos, Frank

    2014-12-01

    Early detection and rapid treatment of tissue hypoxia are important goals. Venous oxygen saturation is an indirect index of global oxygen supply-to-demand ratio. Central venous oxygen saturation (ScvO2) measurement has become a surrogate for mixed venous oxygen saturation (SvO2). ScvO2 is measured by a catheter placed in the superior vena cava. After results from a single-center study suggested that maintaining ScvO2 values >70% might improve survival rates in septic patients, international practice guidelines included this target in a bundle strategy to treat early sepsis. However, a recent multicenter study with >1500 patients found that the use of central hemodynamic and ScvO2 monitoring did not improve long-term survival when compared to the clinical assessment of the adequacy of circulation. It seems that if sepsis is recognized early, a rapid initiation of antibiotics and adequate fluid resuscitation are more important than measuring venous oxygen saturation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Metamaterial saturable absorber mirror.

    Science.gov (United States)

    Dayal, Govind; Ramakrishna, S Anantha

    2013-02-01

    We propose a metamaterial saturable absorber mirror at midinfrared wavelengths that can show a saturation of absorption with intensity of incident light and switch to a reflecting state. The design consists of an array of circular metallic disks separated by a thin film of vanadium dioxide (VO(2)) from a continuous metallic film. The heating due to the absorption in the absorptive state causes the VO(2) to transit to a metallic phase from the low temperature insulating phase. The metamaterial switches from an absorptive state (R≃0.1%) to a reflective state (R>95%) for a specific threshold intensity of the incident radiation corresponding to the phase transition of VO(2), resulting in the saturation of absorption in the metamaterial. The computer simulations show over 99.9% peak absorbance, a resonant bandwidth of about 0.8 μm at 10.22 μm wavelengths, and saturation intensity of 140 mW cm(-2) for undoped VO(2) at room temperature. We also carried out numerical simulations to investigate the effects of localized heating and temperature distribution by solving the heat diffusion problem.

  6. Equivalence between invasive and oscillometric blood pressures at different anatomic locations in healthy normotensive anaesthetised horses.

    Science.gov (United States)

    Tearney, C C; Guedes, A G P; Brosnan, R J

    2016-05-01

    Accurate blood pressure measurement is essential for effective clinical assessment and appropriate interventions in anaesthetised horses. Information on the accuracy of oscillometry for blood pressure measurement on the appendages of mature horses is limited. To assess equivalence between invasive and oscillometric blood pressures at different anatomic locations in horses. Prospective experimental study using 6 healthy mature horses. Blood pressure was measured invasively in the right transverse facial artery and noninvasively by oscillometry in nondependent limbs and tail of laterally recumbent sevoflurane- or desflurane-anaesthetised horses. Cuff widths of 5-12 cm were tested on the tail, metatarsus, metacarpus and distal radius/ulna. Equivalence between mean arterial pressure (MAP) oscillometric and MAP invasive was assessed using a linear mixed effects model with a significance level of P≤0.05. Twenty paired measurements were obtained for each cuff size in each of the locations, totalling 340 measurements. There was only one location (tail) and one cuff width (6 cm; cuff width-to-tail circumference ratio of 0.25) that resulted in equivalence between MAP measured with the oscillometric and the invasive methods (P = 0.8). All other locations (metacarpus, radius/ulna, metatarsus) and cuff widths were not equivalent (P≤0.01). A cuff width-to-tail circumference ratio of 0.25 is recommended for accurate oscillometric blood pressure measurement in mature, laterally recumbent anaesthetised normotensive horses. Studies with variable haemodynamics are warranted. Oscillometric measurements at other extremities and/or with other cuff sizes cannot be recommended for clinical use. © 2015 EVJ Ltd.

  7. Study of blast event propagation in different media using a novel ultrafast miniature optical pressure sensor

    Science.gov (United States)

    Zou, Xiaotian; Wu, Nan; Tian, Ye; Zhang, Hongtao; Niezrecki, Christopher; Wang, Xingwei

    2011-06-01

    Traumatic brain injury (TBI, also called intracranial injury) is a high potential threat to our soldiers. A helmet structural health monitoring system can be effectively used to study the effects of ballistic/blast events on the helmet and human skull to prevent soldiers from TBI. However, one of the biggest challenges lies in that the pressure sensor installed inside the helmet system must be fast enough to capture the blast wave during the transient period. In this paper, an ultrafast optical fiber sensor is presented to measure the blast signal. The sensor is based on a Fabry-Pérot (FP) interferometeric principle. An FP cavity is built between the endface of an etched optical fiber tip and the silica thin diaphragm attached on the end of a multimode optical fiber. The sensor is small enough to be installed in different locations of a helmet to measure blast pressure simultaneously. Several groups of tests regarding multi-layer blast events were conducted to evaluate the sensors' performance. The sensors were mounted in different segments of a shock tube side by side with the reference sensors, to measure a rapidly increasing pressure. The segments of the shock tube were filled with different media. The results demonstrated that our sensors' responses agreed well with those from the electrical reference sensors. In addition, the home-made shock tube could provide a good resource to study the propagation of blast event in different media.

  8. Quantitative 1D saturation profiles on chalk by NMR

    DEFF Research Database (Denmark)

    Olsen, Dan; Topp, Simon; Stensgaard, Anders

    1996-01-01

    Quantitative one-dimensional saturation profiles showing the distribution of water and oil in chalk core samples are calculated from NMR measurements utilizing a 1D CSI spectroscopy pulse sequence. Saturation profiles may be acquired under conditions of fluid flow through the sample. Results reveal...... that strong saturation gradients exist in chalk core samples after core floods, due to capillary effects. The method is useful in analysis of corefloods, e.g., for determination of capillary pressure functions...

  9. A New Robust Solver for Saturated-Unsaturated Richards' Equation

    Science.gov (United States)

    Barajas-Solano, D. A.; Tartakovsky, D. M.

    2012-12-01

    We present a novel approach for the numerical integration of the saturated-unsaturated Richards' equation, a degenerate parabolic partial differential equation that models flow in porous media. The method is based on the mixed (pore pressure-water content) form of RE, written as a set of differential algebraic equations (DAEs) of index-1 for the fully saturated case and index-2 for the partially saturated case. A DAE-based approach allows us to overcome the numerical challenges posed by the degenerate nature of the Richards' equation. The resulting set of DAEs is solved using the stiffly-accurate, single-step, 3-stage implicit Runge-Kutta method Radau IIA, chosen for its favorable accuracy and stability properties, and its ease of implementation. For each time step a nonlinear system of equations on the intermediate Runge-Kutta states of the pore pressure is solved, written so to ensure that the next step pore pressure and water content correspond to one another correctly. The implementation of our approach compares favorably to state-of-the-art DAE-based solvers in both one- and two-dimensional simulations. These solvers use multi-step backward difference formulas together with a pressure-based form of Richards' equation. To the best of our knowledge, our method is the first instance of a successful DAE-based solver that uses the mixed form of Richards' equation. We consider this a promising line of research, with future work to be done on the use of globally convergent methods for the solution of the occurring nonlinear systems of equations.

  10. Dynamic mechanical properties and anisotropy of synthetic shales with different clay minerals under confining pressure

    Science.gov (United States)

    Gong, Fei; Di, Bangrang; Wei, Jianxin; Ding, Pinbo; Shuai, Da

    2018-03-01

    The presence of clay minerals can alter the elastic behaviour of reservoir rocks significantly as the type of clay minerals, their volume and distribution, and their orientation control the shale's intrinsic anisotropic behaviours. Clay minerals are the most abundant materials in shale, and it has been proven extremely difficult to measure the elastic properties of natural shale by means of a single variable (in this case, the type of clay minerals), due to the influences of multiple factors, including water, TOC content and complex mineral compositions. We used quartz, clay (kaolinite, illite and smectite), carbonate and kerogen extract as the primary materials to construct synthetic shale with different clay minerals. Ultrasonic experiments were conducted to investigate the anisotropy of velocity and mechanical properties in dry synthetic and natural shale as a function of confining pressure. Velocities in synthetic shale are sensitive to the type of clay minerals, possibly due to the different structures of the clay minerals. The velocities increase with confining pressure and show higher rate of velocity increase at low pressures, and P-wave velocity is usually more sensitive than S-wave velocity to confining pressure according to our results. Similarly, the dynamic Young's modulus and Poisson's ratio increase with applied pressure, and the results also reveal that E11 is always larger than E33 and ν31 is smaller than ν12. Velocity and mechanical anisotropy decrease with increasing stress, and are sensitive to stress and the type of clay minerals. However, the changes of mechanical anisotropy with applied stress are larger compared with the velocity anisotropy, indicating that mechanical properties are more sensitive to the change of rock properties.

  11. Ride comfort characteristics with different tire pressure of passenger vehicle featuring MR damper

    Energy Technology Data Exchange (ETDEWEB)

    Lee, H G [Department of Automotive Engineering, Daeduk College, Daejeon 305-715 (Korea, Republic of); Sung, K G [Department of Mechanical Engineering, Yeungnam College of Science and Technology, Daegu 705-703 (Korea, Republic of); Choi, S B [Smart Structures and Systems Laboratory, Department of Mechanical Engineering, Inha University, Incheon 402-751 (Korea, Republic of)], E-mail: seungbok@inha.ac.kr

    2009-02-01

    This paper presents ride comfort characteristics of a quarter-vehicle magneto-rheological (MR) suspension system with respect to different tire pressure. As a first step, controllable MR damper is designed and manufactured based on the optimized damping force levels and mechanical dimensions required for a commercial mid-sized passenger vehicle. After experimentally evaluating dynamic characteristics of the manufactured MR damper, the quarter-vehicle suspension system consisting of sprung mass, spring, tire and the MR damper is constructed in order to investigate the ride comfort. After deriving the equations of the motion for the proposed quarter-vehicle MR suspension system, vertical tire stiffness with respect to different tire pressure is experimentally identified. The skyhook controller is then implemented for the realization of quarter-vehicle MR suspension system. Ride comfort characteristics such as vertical acceleration RMS of sprung mass are evaluated under bump road condition and presented in time domain.

  12. Predictors of differences between Type A and B individuals in heart rate and blood pressure reactivity.

    Science.gov (United States)

    Lyness, S A

    1993-09-01

    Past estimates of the magnitude of Type A-B differences in cardiovascular reactivity are probably overly conservative. In addition, it is unclear which situations are more likely to elicit excessive reactivity in Type As. The present meta-analysis found that, overall, Type As had greater heart rate (mean d = .22), diastolic blood pressure (d = .22), and especially systolic blood pressure responses (d = .33) than Type Bs; these effect sizes were small but relatively consistent. However, Type As showed especially greater cardiovascular reactivity in situations characterized as having (a) positive or negative feedback evaluation, (b) socially aversive elements such as verbal harassment or criticism, and (c) elements inherent in playing video games. Measures of time urgency, Type A assessment method, and gender were not found to be strongly related to A-B differences in cardiovascular reactivity. Future studies that use more "Type A-relevant" situations will probably find greater effects.

  13. Effects of Aerobic Exercise Programme with Different Intensities on Blood Pressure and Low Density Lipoproteins

    OpenAIRE

    Dr. Ajayakumar Koorma

    2017-01-01

    The purpose of the present study was to find out the effect of aerobic exercise programme with different intensities on blood pressure and low density lipoproteins among middle aged women. For this purpose, thirty middle aged women residing at various places around Kannur Town, Kerala, were selected as subjects. The age of the subjects were ranged from 35 to 45 years. They were divided into three equal groups, each group consisted of ten subjects, in which experimental group - I underwent aer...

  14. Application and Comparison of Different Combustion Models of High Pressure LO X /CH 4 Jet Flames

    OpenAIRE

    Maria Grazia De Giorgi; Aldebara Sciolti; Antonio Ficarella

    2014-01-01

    The present work focuses on the numerical modeling of combustion in liquid-propellant rocket engines. Pressure and temperature are well above thermodynamic critical points of both the propellants and then the reactants show liquid-like characteristics of density and gas-like characteristics for diffusivity. The aim of the work is an efficient numerical description of the phenomena and RANS simulations were performed for this purpose. Hence, in the present work different kinetics, combustion m...

  15. Application and Comparison of Different Combustion Models of High Pressure LOX/CH4 Jet Flames

    OpenAIRE

    Giorgi, Maria De; Sciolti, Aldebara; Ficarella, Antonio

    2014-01-01

    The present work focuses on the numerical modeling of combustion in liquid-propellant rocket engines. Pressure and temperature are well above thermodynamic critical points of both the propellants and then the reactants show liquid-like characteristics of density and gas-like characteristics for diffusivity. The aim of the work is an efficient numerical description of the phenomena and RANS simulations were performed for this purpose. Hence, in the present work different kinetics, combustion ...

  16. Left ventricular mass index and sports: the influence of different sports activities and arterial blood pressure.

    Science.gov (United States)

    Iglesias Cubero, G; Batalla, A; Rodriguez Reguero, J J; Barriales, R; González, V; de la Iglesia, J L; Terrados, N

    2000-09-15

    The mechanisms by which endurance training produces physiological hypertrophy have been thoroughly investigated but not with young athletes. The aim of our study was to investigate arterial blood pressure exercise responses in young athletes who started heavy training by the age of 11, participating in metabolically different sports (cycling, kayaking, and soccer) and to analyse the influence that arterial blood pressure at maximum exercise and VO(2) max could have on the development of cardiac mass in these subjects. We studied a group of well trained normotensive male subjects, comprising 37 cyclists, 15 soccer players and 12 canoeists (mean age, 16+/-1 years). Evaluation included a clinical history and physical examination, M-mode and two-dimensional echocardiography, 12-lead resting electrocardiogram and a graded exercise test with direct determination of VO(2) max. Systolic and diastolic blood pressure were measured at rest and maximum exercise. Determination of the left ventricular mass index (LVMI) was performed using Devereux's formula with correction for the body surface area. Cyclists showed values of LVMI in g m(-2) significantly higher than those of other subjects (123 vs. 92 and 113). Canoeists showed the maximal arterial blood pressure at maximum exercise in mmHg (190 vs. 172 and 170) and cyclists showed the maximal VO(2) ml kg(-1) min(-1) uptake (57.6 vs. 48.5 and 53.3). A linear correlation was found between LVMI and VO(2) max (r=0.4727, P<0.001) and this correlation was also significant with systolic blood pressure at maximum exercise (r=0.2909, P<0.01). No differences in LVMI were found when comparing those subjects who presented systolic blood pressure at maximum exercise equal or greater than 195 mmHg with those who presented less than this value. It can be concluded that VO(2) max is the variable that better correlates with the LVMI. Athletes who reach greater systolic blood pressures at peak exercise have a tendency to develop greater LVMI. In

  17. Sex differences in step count-blood pressure association: a preliminary study in type 2 diabetes.

    Directory of Open Access Journals (Sweden)

    Priya Manjoo

    Full Text Available BACKGROUND: Walking and cardiovascular mortality are inversely associated in type 2 diabetes, but few studies have objectively measured associations of walking with individual cardiovascular risk factors. Such information would be useful for "dosing" daily steps in clinical practice. This study aimed to quantify decrements in blood pressure and glycated hemoglobin (A1C per 1,000 daily step increments. METHODOLOGY/PRINCIPAL FINDINGS: Two hundred and one subjects with type 2 diabetes underwent assessments of step counts (pedometer-measured, blood pressure, A1C and anthropometric parameters. Due to missing data, the final analysis was conducted on 83 women and 102 men, with a mean age of 60 years. Associations of daily steps with blood pressure and A1C were evaluated using sex-specific multivariate linear regression models (adjusted for age, ethnicity, and BMI. Potential sex differences were confirmed in a combined model (women and men with interaction terms. Mean values for daily steps, blood pressure, A1C and BMI were 5,357 steps/day; 137/80 mm Hg; 7.7% and 30.4 kg/m(2 respectively. A 1,000 daily step increment among women was associated with a -2.6 (95% CI: -4.1 to -1.1 mm Hg change in systolic and a -1.4 (95% CI: -2.2 to -0.6 mm Hg change in diastolic blood pressure. Among men, corresponding changes were -0.7 (95% CI: -2.1 to 0.7 and -0.6 (95% CI: -1.4 to 0.3 mm Hg, respectively. Sex differences were confirmed in combined models. Step counts and A1C did not demonstrate clinically important associations. CONCLUSIONS/SIGNIFICANCE: A 1,000 steps/day increment is associated with important blood pressure decrements among women with type 2 diabetes but the data were inconclusive among men. Targeted "dose increments" of 1,000 steps/day in women may lead to measurable blood pressure reductions. This information may be of potential use in the titration or "dosing" of daily steps. No associations were found between step count increments and A1C.

  18. Acrylic resin water sorption under different pressure, temperature and time conditions

    Directory of Open Access Journals (Sweden)

    Rizzatti-Barbosa Célia Marisa

    2001-01-01

    Full Text Available The purpose of this work was to analyze water sorption by polymerized acrylic resins under different pressure, temperature and time treatments. A thermo-cured acrylic resin was used as the denture base (Classico Ltda. and ethylene glycol di-methacrylate as a cross-linking agent, with processing carried out in a water bath at 73 °C for nine hours. Forty-five samples were prepared following the criteria and dimensions of specification # 12 of the American Dental Association (ADA, using a matrix in the shape of a stainless steel disc with 50 ± 1 mm diameter and 0.5 ± 0.05 mm thickness. The control group samples were stored in distilled water for 30 days, while groups GII to GIX were placed in a polymerization device with adjustable pressure, time and temperature. An analysis of the variance of the results revealed the influence of different factors on water sorption only, with significant factors being temperature, time, pressure and the interaction between time and temperature. Other interactions exerted no significant influence on water sorption. Neither additional treatments nor the control group (GI showed any significant difference in comparison to the averages of other treatments.

  19. Literature review and meta-analysis of translaminar pressure difference in open-angle glaucoma.

    Science.gov (United States)

    Siaudvytyte, L; Januleviciene, I; Daveckaite, A; Ragauskas, A; Bartusis, L; Kucinoviene, J; Siesky, B; Harris, A

    2015-10-01

    There is increasing evidence in the literature regarding translaminar pressure difference's (TPD) role in the pathophysiology of glaucoma. The optic nerve is exposed not only to intraocular pressure in the eye, but also to intracranial pressure (ICP), as it is surrounded by cerebrospinal fluid in the subarachnoid space. Although pilot studies have identified the potential importance of TPD in glaucoma, limited available data currently prevent a comprehensive description of the role that TPD may have in glaucomatous pathophysiology. In this review, we present all available qualified data from a systematic review of the literature of the role of TPD in open-angle glaucoma (OAG). PubMed (Medline), OVID Medline, ScienceDirect, SpringerLink, and all available library databases were reviewed and subsequent meta-analysis of pooled mean differences are presented where appropriate. Five papers including 396 patients met criteria for inclusion to the analysis. Importantly, we included all observational studies despite differences in ICP measurement methods, as there is no consensus regarding best-practice ICP measurements in glaucoma. Our results show that not only TPD is higher in glaucoma patients compared with healthy subjects, it is related to structural glaucomatous changes of the optic disc. Our analysis suggests further longitudinal prospective studies are needed to investigate the influence of TPD in OAG, with a goal of overcoming methodological weaknesses of previous studies.

  20. Saturation of the turbulent dynamo.

    Science.gov (United States)

    Schober, J; Schleicher, D R G; Federrath, C; Bovino, S; Klessen, R S

    2015-08-01

    The origin of strong magnetic fields in the Universe can be explained by amplifying weak seed fields via turbulent motions on small spatial scales and subsequently transporting the magnetic energy to larger scales. This process is known as the turbulent dynamo and depends on the properties of turbulence, i.e., on the hydrodynamical Reynolds number and the compressibility of the gas, and on the magnetic diffusivity. While we know the growth rate of the magnetic energy in the linear regime, the saturation level, i.e., the ratio of magnetic energy to turbulent kinetic energy that can be reached, is not known from analytical calculations. In this paper we present a scale-dependent saturation model based on an effective turbulent resistivity which is determined by the turnover time scale of turbulent eddies and the magnetic energy density. The magnetic resistivity increases compared to the Spitzer value and the effective scale on which the magnetic energy spectrum is at its maximum moves to larger spatial scales. This process ends when the peak reaches a characteristic wave number k☆ which is determined by the critical magnetic Reynolds number. The saturation level of the dynamo also depends on the type of turbulence and differs for the limits of large and small magnetic Prandtl numbers Pm. With our model we find saturation levels between 43.8% and 1.3% for Pm≫1 and between 2.43% and 0.135% for Pm≪1, where the higher values refer to incompressible turbulence and the lower ones to highly compressible turbulence.

  1. The Use of the Ratio between the Veno-arterial Carbon Dioxide Difference and the Arterial-venous Oxygen Difference to Guide Resuscitation in Cardiac Surgery Patients with Hyperlactatemia and Normal Central Venous Oxygen Saturation

    Directory of Open Access Journals (Sweden)

    Wei Du

    2015-01-01

    Full Text Available Background: After cardiac surgery, central venous oxygen saturation (ScvO 2 and serum lactate concentration are often used to guide resuscitation; however, neither are completely reliable indicators of global tissue hypoxia. This observational study aimed to establish whether the ratio between the veno-arterial carbon dioxide and the arterial-venous oxygen differences (P(v−aCO 2 /C(a−vO 2 could predict whether patients would respond to resuscitation by increasing oxygen delivery (DO 2 . Methods: We selected 72 patients from a cohort of 290 who had undergone cardiac surgery in our institution between January 2012 and August 2014. The selected patients were managed postoperatively on the Intensive Care Unit, had a normal ScvO 2 , elevated serum lactate concentration, and responded to resuscitation by increasing DO 2 by >10%. As a consequence, 48 patients responded with an increase in oxygen consumption (VO 2 while VO 2 was static or fell in 24. Results: At baseline and before resuscitative intervention in postoperative cardiac surgery patients, a P(v−aCO 2 /C(a−vO 2 ratio ≥1.6 mmHg/ml predicted a positive VO 2 response to an increase in DO 2 of >10% with a sensitivity of 68.8% and a specificity of 87.5%. Conclusions: P(v−aCO 2 /C(a−vO 2 ratio appears to be a reliable marker of global anaerobic metabolism and predicts response to DO 2 challenge. Thus, patients likely to benefit from resuscitation can be identified promptly, the P(v−aCO 2 /C(a−vO 2 ratio may, therefore, be a useful resuscitation target.

  2. Modelling suction instabilities in soils at varying degrees of saturation

    Directory of Open Access Journals (Sweden)

    Buscarnera Giuseppe

    2016-01-01

    Full Text Available Wetting paths imparted by the natural environment and/or human activities affect the state of soils in the near-surface, promoting transitions across different regimes of saturation. This paper discusses a set of techniques aimed at quantifying the role of hydrologic processes on the hydro-mechanical stability of soil specimens subjected to saturation events. Emphasis is given to the mechanical conditions leading to coupled flow/deformation instabilities. For this purpose, energy balance arguments for three-phase systems are used to derive second-order work expressions applicable to various regimes of saturation. Controllability analyses are then performed to relate such work input with constitutive singularities that reflect the loss of strength under coupled and/or uncoupled hydro-mechanical forcing. A suction-dependent plastic model is finally used to track the evolution of stability conditions in samples subjected to wetting, thus quantifying the growth of the potential for coupled failure modes upon increasing degree of saturation. These findings are eventually linked with the properties of the field equations that govern pore pressure transients, thus disclosing a conceptual link between the onset of coupled hydro-mechanical failures and the evolution of suction with time. Such results point out that mathematical instabilities caused by a non-linear suction dependent behaviour play an important role in the advanced constitutive and/or numerical tools that are commonly used for the analysis of geomechanical problems in the unsaturated zone, and further stress that the relation between suction transients and soil deformations is a key factor for the interpretation of runaway failures caused by intense saturation events.

  3. A study on the saturation degree dependency of the seismic behaviour of retaining walls

    Directory of Open Access Journals (Sweden)

    Momeni M.J.

    2016-01-01

    Full Text Available Retaining walls are important geotechnical structures that are often used in soil slopes and trenches to bring ground surface at appropriate level for the construction of roads, highways and buildings. It is common practice to assume that the soil behind a retaining structure is either fully saturated or completely dry. However, for the case the soil is partially saturated, mechanical behaviour of the soil above the water table is different than that of the dry soil. Thus, it is necessary to investigate the effect of the variations of degree of saturation on lateral pressure behind retaining walls. In this research, the seismic behaviour of unsaturated soils behind a retaining structure is analysed. A finite difference code was employed to conduct the necessary analyses and a series of equivalent linear analyses is performed to reveal the effect of the degree of saturation on the general response of the retaining structures. The required functions for unsaturated zone were defined and implemented in the code. For this purpose, a soil water retention function was employed and the soil shear modulus is assumed to vary with the mean effective stress for both saturated and unsaturated zones which naturally introduces the required hydro-mechanical coupling in unsaturated and saturated zone. The results of the analyses compared to the conventional methods which does not include the unsaturated mechanical properties, indicate that in the unsaturated state, the increase in the effective stress, and hence, the shear modulus considerably affects the seismic forces on the retaining wall.

  4. Saturated and trans fats

    National Research Council Canada - National Science Library

    Shader, Richard I

    2014-01-01

    ... Original Pancake Mix plus ingredients suggested by the recipe: 2 g saturated fat (SF) and no trans fatty acids or trans fat (TFA); bacon, Oscar Mayer Lower Sodium Bacon: 2.5 g SF and no TFA; sausages, Jimmy Dean Original Pork Sausage Links: 8 g SF and no TFA; potatoes, Ore-Ida Mini Tater Tots: 2 g SF and no TFA; and nondairy creamer, Nestlé Coffee-...

  5. Mean Blood Pressure Assessment during Post-Exercise: Result from Two Different Methods of Calculation

    Directory of Open Access Journals (Sweden)

    Gianmarco Sainas, Raffaele Milia, Girolamo Palazzolo, Gianfranco Ibba, Elisabetta Marongiu, Silvana Roberto, Virginia Pinna, Giovanna Ghiani, Filippo Tocco, Antonio Crisafulli

    2016-09-01

    Full Text Available At rest the proportion between systolic and diastolic periods of the cardiac cycle is about 1/3 and 2/3 respectively. Therefore, mean blood pressure (MBP is usually calculated with a standard formula (SF as follows: MBP = diastolic blood pressure (DBP + 1/3 [systolic blood pressure (SBP – DBP]. However, during exercise this proportion is lost because of tachycardia, which shortens diastole more than systole. We analysed the difference in MBP calculation between the SF and a corrected formula (CF which takes into account changes in the diastolic and systolic periods caused by exercise-induced tachycardia. Our hypothesis was that the SF potentially induce a systematic error in MBP assessment during recovery after exercise. Ten healthy males underwent two exercise-recovery tests on a cycle-ergometer at mild-moderate and moderate-heavy workloads. Hemodynamics and MBP were monitored for 30 minutes after exercise bouts. The main result was that the SF on average underestimated MBP by –4.1 mmHg with respect to the CF. Moreover, in the period immediately after exercise, when sustained tachycardia occurred, the difference between SF and CF was large (in the order of -20-30 mmHg. Likewise, a systematic error in systemic vascular resistance assessment was present. It was concluded that the SF introduces a substantial error in MBP estimation in the period immediately following effort. This equation should not be used in this situation.

  6. Graph-analytical method for determining saturation in oil formations

    Energy Technology Data Exchange (ETDEWEB)

    Ramazanova, E.E.; Fedortsov, V.K.; Ismaylov, K.K.

    1980-01-01

    Factual material is generalized for a large number of oil fields of the Soviet Union for which probability-statistical models have been selected. A graph-analytical method is developed for determining the saturation pressure of oil by gas.

  7. In situ 15N labeling experiment reveals different long-term responses to ammonium and nitrate inputs in N-saturated subtropical forest

    Science.gov (United States)

    Liu, Wenjing; Yu, Longfei; Zhang, Ting; Kang, Ronghua; Zhu, Jing; Mulder, Jan; Huang, Yongmei; Duan, Lei

    2017-09-01

    Chronically elevated deposition of reactive nitrogen (N), as ammonium (NH4+) and nitrate (NO3-), in subtropical forests with monsoonal climate has caused widespread N leaching in southern China. So far, little is known about the effect of further increases in N input and changes in the relative proportion of NH4+ and NO3- on turnover rate and fate of atmogenic N. Here we report a 15N tracer experiment in Tieshanping (TSP) forest, SW China, conducted as part of a long-term N fertilization experiment, using NH4NO3 and NaNO3, where effects of a doubling of monthly N inputs were compared. In June 2012, the regular N fertilizers were replaced by their 15N-labeled forms, viz., 15NH4NO3 and Na15NO3, as a single-dose addition. Mass balances of N for the initial 1.5 years following label addition showed that for both treatments, 70% to 80% of the annual N input was leached as NO3-, both at ambient and at double N input rates. This confirms the earlier reported extreme case of N saturation at TSP. The 15N, added as Na15NO3, showed recoveries of about 74% in soil leachates, indicating that NO3- input at TSP is subject to a rapid and nearly quantitative loss through direct leaching as a mobile anion. By contrast, recoveries of 15N in soil leachates of only 33% were found if added as 15NH4NO3. Much of the 15N was immobilized in the soil and to a lesser extent in the vegetation. Thus, immobilization of fresh N input is significantly greater if added as NH4+, than as NO3-.

  8. Comparison of the effects of four different cochlear implant electrodes on intra-cochlear pressure in a model.

    Science.gov (United States)

    Todt, Ingo; Mittmann, Marlene; Ernst, Arneborg; Mittmann, Philipp

    2017-03-01

    Based on this model experiment, a small tip and low volume electrode show lowest intra-cochlear pressure values. Insertional support by a tool minimizes fast pressure changes. Higher electrodes volumes affect slow and fast pressure changes as well. Insertion causing low intra-cochlear pressure is assumed to be important for atraumatic cochlear implant surgery to preserve residual hearing. Cochlear implant electrodes differ in terms of parameters like tip size, length, volume, and technique of insertion. The aim of this study was to observe the effect of different cochlear implant electrodes on insertional intra-cochlear pressure in a cochlear model. Cochlear implant electrode insertions were performed in an artificial cochlear model and intra-cochlear pressure changes were recorded in parallel with a micro-pressure sensor positioned in the apical region of the cochlear model to follow the maximum values, temporal changes, maximum amplitude, and frequency of changes in intra-cochlear pressure. Insertions were performed with four different electrodes (Advanced Bionics 1j, Helix, HFMS, and LW23). This study found statistically significant differences in the occurrence of initial maximum pressure values correlating with the electrode tip size. The different electrodes and the technique of insertion significantly affected the occurrence of maximum value, amplitude, and frequency of intra-cochlear pressure occurrence.

  9. Effects of different block size distributions in pressure transient response of naturally fractured reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Montazeri, G.H. [Islamic Azad University, Mahshahr (Iran, Islamic Republic of). Dept. of Chemical and Petroleum Engineering], E-mail: montazeri_gh@yahoo.com; Tahami, S.A. [Mad Daneshgostar Tabnak Co. (MDT),Tehran (Iran, Islamic Republic of); Moradi, B.; Safari, E. [Iranian Central Oil Fields Co, Tehran (Iran, Islamic Republic of)], E-mail: morady.babak@gmail.com

    2011-07-15

    This paper presents a model for pressure transient and derivative analysis for naturally fractured reservoirs by a formulation of inter porosity flow incorporating variations in matrix block size, which is inversely related to fracture intensity. Geologically realistic Probability Density Functions (PDFs) of matrix block size, such as uniform, bimodal, linear and exponential distributions, are examined and pseudo-steady-state and transient models for inter porosity flow are assumed. The results have been physically interpreted, and, despite results obtained by other authors, it was found that the shape of pressure derivative curves for different PDFs are basically identical within some ranges of block size variability, inter porosity skin, PDFs parameters and matrix storage capacity. This tool can give an insight on the distribution of block sizes and shapes, together with other sources of information such as Logs and geological observations. (author)

  10. Positron Annihilation and Complementary Studies of Copper Sandblasted with Alumina Particles at Different Pressures

    Directory of Open Access Journals (Sweden)

    Paweł Horodek

    2017-11-01

    Full Text Available Positron annihilation spectroscopy and complementary methods were used to detect changes induced by sandblasting of alumina particles at different pressures varying from 1 to 6 bar in pure well-annealed copper. The positron lifetime measurements revealed existence of dislocations and vacancy clusters in the adjoined surface layer. The presence of retained alumina particles in the copper at the depth below 50 µm was found in the SEM pictures and also in the annihilation line shape parameter profiles measured in the etching experiment. The profiles show us that the total depth of damaged zones induced by sandblasting of alumina particles ranges from 140 µm up to ca. 800 µm and it depends on the applied pressure. The work-hardening of the adjoined surface layer was found in the microhardness measurements at the cross-section of the sandblasted samples.

  11. Effects of tractor loads and tyre pressures on soil compaction in Tunisia under different moisture conditions

    Science.gov (United States)

    Khemis, Chiheb; Abrougui, Khaoula; Ren, Lidong; Mutuku, Eunice Ann; Chehaibi, Sayed; Cornelis, Wim

    2017-04-01

    Vegetables in Tunisia demand frequent tractor traffic for soil tillage, cultural operations and phytosanitary treatment, resulting in soil compaction. This study evaluates the effects of four levels of compaction by using different loads and tyre pressures of tractors, i.e., load 1 (C1) = 1460 kg, load 2 (C2) = 3100 kg, tyre pressure 1 (C3) = 800 kg cm-2, tyre pressure 2 (C4) = 1500 kg cm-2 on the hydraulic and physical properties of a sandy loam (10% clay, 20% silt, 68% sand) under three natural moisture conditions H0, H1 (15 days later), H2 (30 days later). At H0 average water content between 0 and 30 cm depth varied from 0.04 to 0.06 kg kg-1, at H1 between 0.13 and 0.07 kg kg-1, and at H2 between 0.10 and 0.09 kg kg-1. Each test run was limited to one pass. Undisturbed soil cores were collected in the topsoil (0-10 cm), at 10-20 cm and in the subsoil (20-30 cm) below the trace of the wheel at sites in the Higher Institute of Agronomy of Chott Mariam, Sousse, Tunisia. Soil compaction level was determined by penetration resistance using a penetrologger. Porosity, bulk density and permeability were then determined to evaluate the impact of the four load/tyre pressure combinations at the three moisture conditions on soil compaction. Prior to the experiment (C0), bulk density was 1.4 Mg m-3. After the tractor pass, the highest degree of compaction was observed with tractor load C2 and tyre pressure C4 which significantly changed soil bulk density resulting in values of up to 1.71 Mg m-3 in the topsoil and compacted subsoil under H2, which is significantly above the critical value of 1.6 Mg m-3 for soils with clay content below 17.5%. The high degree of compaction significantly affected penetration resistance and porosity of both topsoil and subsoil layers accordingly. Permeability was significantly reduced as a result of the induced compaction. The results demonstrate that different degrees of soil compaction under different moisture levels could greatly influence

  12. Difference between central and peripheral blood pressure in healthy and hypertension-complicated pregnancy.

    Science.gov (United States)

    Szczepaniak-Chicheł, Ludwina; Markwitz, Wiesław; Tykarski, Andrzej

    2016-04-01

    Hemodynamics of a pregnant woman differ and change over time depending on the age of gestation. In the general population, brachial-aortic systolic pressure (SBP-AoSP) difference is known and discussed, whereas in pregnancy, it is not established. On the basis of theoretical premises it is probably different and changes with time of gestation. As AoSP is more relevant for internal organs, also for placental perfusion, and still not widely available in clinical practice, knowledge of the average SBP-AoSP difference in a healthy and complicated pregnancy could be of additional value for the management of pregnancy hypertension. The aim of this study was to assess the SBP-AoSP difference in healthy and hypertensive pregnancies in comparison with nonpregnant controls. Aortic blood pressure with applanation tonometry and brachial blood pressure under standardized conditions were measured monthly and once postpartum in 36 normotensive pregnant women (age: 29.6±4.8 years) and compared with 25 hypertensive pregnancies (age: 30.5±5.4 years) before antihypertensive treatment implementation and with 25 nonpregnant controls (age: 30.2±5.5 years). In hypertensive pregnancies, the SBP-AoSP difference was smaller throughout the entire pregnancy than in healthy pregnancies (in the second and third trimester: 14.44 vs. 15.7 mmHg, P=0.002, and 12.9 vs. 14 mmHg, P=0.02), and smaller than that in nonpregnant controls (14.88 mmHg, for third trimester, P=0.036). Comparison of healthy pregnancy and controls showed an insignificant increase in SBP-AoSP difference in the first and second trimester, whereas in the third trimester, because of a larger increase of AoSP, the SBP-AoSP difference was smaller than that in nonpregnant controls (14.66 mmHg, P>0.05). A reduced SBP-AoSP difference was found in hypertensive pregnancies compared with healthy controls, which may signify a narrower safety margin for complications. Comparison of pregnant women with nonpregnant controls showed

  13. Test of Scintillometer Saturation Correction Methods Using Field Experimental Data

    NARCIS (Netherlands)

    Kleissl, J.; Hartogensis, O.K.; Gomez, J.D.

    2010-01-01

    Saturation of large aperture scintillometer (LAS) signals can result in sensible heat flux measurements that are biased low. A field study with LASs of different aperture sizes and path lengths was performed to investigate the onset of, and corrections for, signal saturation. Saturation already

  14. Epworth's sleepiness scale in outpatients with different values of arterial blood pressure

    Directory of Open Access Journals (Sweden)

    Miguel Gus

    2002-01-01

    Full Text Available OBJECTIVE: To compare sleepiness scores of the Epworth scale in patients with different levels of arterial pressure when undergoing outpatient monitoring within the context of clinical evaluation. METHODS: A total of 157 patients selected for outpatient monitoring of arterial pressure during hypertension evaluation were divided into 3 groups: group 1 - normotensive; group 2 - hypertensive; group 3 - resistant hypertensive. For analysis, values > or = 11 were considered as associated with respiratory disturbances during sleep. RESULTS: Seventeen (10.8% patients in group 1, 112 (71.3% in group 2, and 28 (17.8% in group 3, which was composed of aged, more severely hypertensive individuals, were analyzed. Groups were similar relative to sex and body mass index, but different in relation to systolic and diastolic pressure levels and age. Despite an absolute difference, no statistically significant difference occurred between Epworth scores and in the proportion of patients with values > or = 11 (5.9% vs. 18.8% vs. 212.4%; P=0.37. Despite the positive association between degree of sleepiness measured with the scale and the severity of the hypertension, no statistical significance occurred following control by age (p=0.18. CONCLUSION: A positive correlation exists between degree of sleepiness and hypertension severity. The absence of a statistical significance shown in the present study could be due to a beta type of error. Instruments that render this complaint into an objective finding could help in the pursuit of an investigation of respiratory disturbances during sleep in more severely hypertensive patients, and should therefore be studied better.

  15. Analysis for pressure transient of coalbed methane reservoir based on Laplace transform finite difference method

    Directory of Open Access Journals (Sweden)

    Lei Wang

    2015-09-01

    Full Text Available Based on fractal geometry, fractal medium of coalbed methane mathematical model is established by Langmuir isotherm adsorption formula, Fick's diffusion law, Laplace transform formula, considering the well bore storage effect and skin effect. The Laplace transform finite difference method is used to solve the mathematical model. With Stehfest numerical inversion, the distribution of dimensionless well bore flowing pressure and its derivative was obtained in real space. According to compare with the results from the analytical method, the result from Laplace transform finite difference method turns out to be accurate. The influence factors are analyzed, including fractal dimension, fractal index, skin factor, well bore storage coefficient, energy storage ratio, interporosity flow coefficient and the adsorption factor. The calculating error of Laplace transform difference method is small. Laplace transform difference method has advantages in well-test application since any moment simulation does not rely on other moment results and space grid.

  16. Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Michael Batzle

    2006-04-30

    During this last period of the ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' project (Grant/Cooperative Agreement DE-FC26-02NT15342), we finalized integration of rock physics, well log analysis, seismic processing, and forward modeling techniques. Most of the last quarter was spent combining the results from the principal investigators and come to some final conclusions about the project. Also much of the effort was directed towards technology transfer through the Direct Hydrocarbon Indicators mini-symposium at UH and through publications. As a result we have: (1) Tested a new method to directly invert reservoir properties, water saturation, Sw, and porosity from seismic AVO attributes; (2) Constrained the seismic response based on fluid and rock property correlations; (3) Reprocessed seismic data from Ursa field; (4) Compared thin layer property distributions and averaging on AVO response; (5) Related pressures and sorting effects on porosity and their influence on DHI's; (6) Examined and compared gas saturation effects for deep and shallow reservoirs; (7) Performed forward modeling using geobodies from deepwater outcrops; (8) Documented velocities for deepwater sediments; (9) Continued incorporating outcrop descriptive models in seismic forward models; (10) Held an open DHI symposium to present the final results of the project; (11) Relations between Sw, porosity, and AVO attributes; (12) Models of Complex, Layered Reservoirs; and (14) Technology transfer Several factors can contribute to limit our ability to extract accurate hydrocarbon saturations in deep water environments. Rock and fluid properties are one factor, since, for example, hydrocarbon properties will be considerably different with great depths (high pressure) when compared to shallow properties. Significant over pressure, on the other hand will make the rocks behave as if they were shallower. In addition to the physical properties, the scale and

  17. Inter-arm blood pressure differences compared with ambulatory monitoring: a manifestation of the ‘white-coat’ effect?

    Science.gov (United States)

    Martin, Una; Holder, Roger; Hodgkinson, James; McManus, Richard

    2013-01-01

    Background Inter-arm difference in blood pressure of >10 mmHg is associated with peripheral vascular disease, but it is unclear how much of the difference in sequential right and left arm blood pressure measurements might be due to a ‘white-coat’ effect. Aim To use ambulatory blood pressure monitoring (ABPM) to better understand the clinical significance of inter-arm differences in blood pressure. Design and setting Retrospective study in a teaching hospital in Birmingham. Method Anonymised clinical data collected from 784 patients attending a single hospital-based hypertension clinic were retrospectively analysed. Each participant had blood pressure measured sequentially in both arms, followed by ABPM over the subsequent 24 hours. Result Data were available for 710 (91%) patients, of whom 39.3% (279) had a blood pressure difference of 10 mmHg or more between each arm. Compared to daytime systolic ABPM, the difference was 25.1 mmHg using the arm with the highest reading, but only 15.5 mmHg if the lower reading was taken (mean difference 9.6 mmHg (95% confidence interval [CI] = 9.0 mmHg to 10.3 mmHg)). However, differences between mean right (20.7 mmHg) or left (19.9 mmHg) arm blood pressure and daytime systolic ABPM were very similar. Conclusion Compared with ABPM, use of the higher of the left and right arm readings measured sequentially appears to overestimate true mean blood pressure. As there is no significant difference in the extent of disparity with ABPM by left or right arm, this is unlikely to be due to arm dominance and may be due to the ‘white-coat’ effect reducing blood pressure on repeated measurement. Where a large inter-arm blood pressure difference is detected with sequential measurement, healthcare professionals should re-measure the blood pressure in the original arm. PMID:23561681

  18. Mechanisms of blood pressure regulation that differ in men repeatedly exposed to high-G acceleration

    Science.gov (United States)

    Convertino, V. A.

    2001-01-01

    The purpose of this study was to test the hypothesis that repeated exposure to high acceleration (G) would be associated with enhanced functions of specific mechanisms of blood pressure regulation. We measured heart rate (HR), stroke volume (SV), cardiac output (), mean arterial blood pressure, central venous pressure, forearm and leg vascular resistance, catecholamines, and changes in leg volume (%DeltaLV) during various protocols of lower body negative pressure (LBNP), carotid stimulation, and infusions of adrenoreceptor agonists in 10 males after three training sessions on different days over a period of 5-7 days using a human centrifuge (G trained). These responses were compared with the same measurements in 10 males who were matched for height, weight, and fitness but did not undergo G training (controls). Compared with the control group, G-trained subjects demonstrated greater R-R interval response to equal carotid baroreceptor stimulation (7.3 +/- 1.2 vs. 3.9 +/- 0.4 ms/mmHg, P = 0.02), less vasoconstriction to equal low-pressure baroreceptor stimulation (-1.4 +/- 0.2 vs. -2.6 +/- 0.3 U/mmHg, P = 0.01), and higher HR (-1.2 +/- 0.2 vs. -0.5 +/- 0.1 beats. min(-1). mmHg(-1), P = 0.01) and alpha-adrenoreceptor response (32.8 +/- 3.4 vs. 19.5 +/- 4.7 U/mmHg, P = 0.04) to equal dose of phenylephrine. During graded LBNP, G-trained subjects had less decline in and SV, %DeltaLV, and elevation in thoracic impedance. G-trained subjects also had greater total blood (6,497 +/- 496 vs. 5,438 +/- 228 ml, P = 0.07) and erythrocyte (3,110 +/- 364 vs. 2,310 +/- 96 ml, P = 0.06) volumes. These results support the hypothesis that exposure to repeated high G is associated with increased capacities of mechanisms that underlie blood pressure regulation.

  19. Effect of CO2 partial pressure and different CO2 phases on carbon steel corrosion

    Science.gov (United States)

    Mahlobo, MGR; Premlall, K.; Olubambi, PA

    2017-12-01

    Carbon capture and storage (CCS) is the recent promising technology aimed at reducing greenhouse gas emission. Like many other developed technologies, CCS is faced with great challenges such as pipeline transportation failure due to corrosion. There are many factors contributing to steel corrosion during the pipeline transportation of carbon dioxide (CO2). This study focuses on CO2 partial pressure and different phases of CO2 as some of the factors contributing to steel corrosion. Carbon steel was used as a testing specimen. High pressure reactor was used in this study to compress CO2 from low to high pressures ultimately changing the CO2 from gaseous phase to gas/liquid phase (subcritical) and to dense phase (supercritical). Weight loss method was employed to determine the corrosion rate while scanning electron microscopy (SEM) and X-Ray diffraction (XRD) were used to study the carbon steel morphology and phase analysis. Using low magnification digital camera, the type of corrosion that took place on the carbon steel surface was identified.

  20. Differences in circadian time structure of diastolic blood pressure between diabetes mellitus and essential hypertension

    Directory of Open Access Journals (Sweden)

    Matteucci Elena

    2012-12-01

    Full Text Available Abstract Background Abnormal circadian blood pressure patterns have been associated with cardiovascular disease in diabetes mellitus. We have described that the acrophase of diastolic blood pressure (DBP registered in type 1 diabetes (T1D patients was significantly earlier than normal and DBP ecphasia was more pronounced in patients with lower heart rate variability during deep breathing. The aim of this study was to compare the circadian rhythm characteristics of BP among different groups: normotensive (NT control subjects, patients affected by T1D and type 2 diabetes (T2D, and patients with essential hypertension (HT. Findings We retrospectively evaluated ambulatory blood pressure monitoring records in 30 NT, 20 T1D, 20 T2D, 20 HT whose fasting plasma glucose and HbA1c were contemporaneously measured. The four groups were well-matched regarding age, gender, and BMI. Systolic blood pressure (SBP and DBP midline-estimating statistic of rhythm were higher in T1D, T2D, and HT groups. DBP ecphasia was present only in the diabetic individuals: the acrophase of DBP occurred four hours earlier than normal in T1D group, whereas two hours earlier in T2D group. In a multiple regression analysis, only HbA1c and SBP acrophase were statistically significant correlates of DBP acrophase. Conclusions People with diabetes mellitus, both type 1 and type 2, have their circadian acrophase of DBP occurring 2–4 hours earlier than normotensive and hypertensive subjects. Altered circadian timing of DBP, potential trigger of cardiovascular events, seems to be a distinguishing feature of diabetes mellitus and correlates with the previous 2–3 months of glycaemic control.

  1. Gender difference in blood pressure control and cardiovascular risk factors in Americans with diagnosed hypertension.

    Science.gov (United States)

    Ong, Kwok Leung; Tso, Annette W K; Lam, Karen S L; Cheung, Bernard M Y

    2008-04-01

    Hypertension is an important risk factor for cardiovascular disease, which is the leading cause of death in women. We, therefore, analyzed gender-specific trends in the control of blood pressure and prevalence of 5 other cardiovascular risk factors (central obesity, elevated total cholesterol, low high-density lipoprotein cholesterol, hyperglycemia, and smoking) among adults with diagnosed hypertension in the United States. We included 3475 participants aged >or=18 years with diagnosed hypertension in the National Health and Nutrition Examination Survey 1999-2004. The age-adjusted prevalence of uncontrolled blood pressure was 50.8+/-2.1% in men and 55.9+/-1.5% in women, which were not significantly different and had not changed significantly with time. Central obesity, elevated total cholesterol level, and low high-density lipoprotein cholesterol were significantly more prevalent in women than in men (79.0+/-1.0%, 61.3+/-1.6%, and 39.7+/-1.6% versus 63.9+/-1.6%, 48.1+/-1.8%, and 35.6+/-1.7%, respectively; Por=3 of the 6 risk factors studied was higher in women than in men (52.5+/-1.4% versus 40.9+/-1.8%; Pblood pressure control in women with diagnosed hypertension was not significantly inferior compared with men and had not changed significantly in 1999-2004. However, women had higher prevalence of other concomitant cardiovascular risk factors. Although there is room for improvement in blood pressure control, our study has highlighted the importance of addressing concomitant cardiovascular risk factors in women with hypertension.

  2. The effect of different unstable footwear constructions on centre of pressure motion during standing.

    Science.gov (United States)

    Plom, W; Strike, S C; Taylor, M J D

    2014-06-01

    The aim of this study was to test the effect different unstable footwear constructions have on centre of pressure motion when standing. Sixteen young female volunteers were tested in five conditions, three unstable footwear (Reebok Easy-Tone, FitFlop and Skechers Shape-Ups), a standard shoe and barefoot in a randomised order. Double and single leg balance on a force plate was assessed via centre of pressure excursions and displacements in each condition. For double leg and single leg standing centre of pressure excursions in the anterior-posterior direction were significantly increased wearing Skechers Shape-Ups compared to barefoot and the standard shoe. For the Reebok Easy Tone during single leg standing excursions in the anterior-posterior direction were significantly greater compared to the barefoot condition. Cumulative displacement of the centre of pressure in medial-lateral direction increased significantly during single leg standing when wearing Skechers Shape-Ups compared to barefoot and standard shoe as well as for Reebok Easy Tone vs. barefoot. It would appear from these quiet standing results that the manner of the construction of instability shoes effects the CoP movement which is associated with induced instability. Greater CoP excursion occurred in the A-P direction while the cumulative displacements were greater in the M-L direction for those shoes with the rounded sole and soft foam and those with airpods. The shoe construction with altered density foam did not induce any change in the CoP movement, during quite standing, which tends to suggest that it is not effective at inducing balance. Not all instability shoes are effective in altering the overall instability of the wearer. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Influence of the Saturation Ratio on Concrete Behavior under Triaxial Compressive Loading

    Directory of Open Access Journals (Sweden)

    Xuan-Dung Vu

    2015-01-01

    Full Text Available When a concrete structure is subjected to an impact, the material is subjected to high triaxial compressive stresses. Furthermore, the water saturation ratio in massive concrete structures may reach nearly 100% at the core, whereas the material dries quickly on the skin. The impact response of a massive concrete wall may thus depend on the state of water saturation in the material. This paper presents some triaxial tests performed at a maximum confining pressure of 600 MPa on concrete representative of a nuclear power plant containment building. Experimental results show the concrete constitutive behavior and its dependence on the water saturation ratio. It is observed that as the degree of saturation increases, a decrease in the volumetric strains as well as in the shear strength is observed. The coupled PRM constitutive model does not accurately reproduce the response of concrete specimens observed during the test. The differences between experimental and numerical results can be explained by both the influence of the saturation state of concrete and the effect of deviatoric stresses, which are not accurately taken into account. The PRM model was modified in order to improve the numerical prediction of concrete behavior under high stresses at various saturation states.

  4. Atmospheric pressure chemical ionization studies of non-polar isomeric hydrocarbons using ion mobility spectrometry and mass spectrometry with different ionization techniques

    Science.gov (United States)

    Borsdorf, H.; Nazarov, E. G.; Eiceman, G. A.

    2002-01-01

    The ionization pathways were determined for sets of isomeric non-polar hydrocarbons (structural isomers, cis/trans isomers) using ion mobility spectrometry and mass spectrometry with different techniques of atmospheric pressure chemical ionization to assess the influence of structural features on ion formation. Depending on the structural features, different ions were observed using mass spectrometry. Unsaturated hydrocarbons formed mostly [M - 1]+ and [(M - 1)2H]+ ions while mainly [M - 3]+ and [(M - 3)H2O]+ ions were found for saturated cis/trans isomers using photoionization and 63Ni ionization. These ionization methods and corona discharge ionization were used for ion mobility measurements of these compounds. Different ions were detected for compounds with different structural features. 63Ni ionization and photoionization provide comparable ions for every set of isomers. The product ions formed can be clearly attributed to the structures identified. However, differences in relative abundance of product ions were found. Although corona discharge ionization permits the most sensitive detection of non-polar hydrocarbons, the spectra detected are complex and differ from those obtained with 63Ni ionization and photoionization. c. 2002 American Society for Mass Spectrometry.

  5. Arterial pressure-based cardiac output in septic patients: different accuracy of pulse contour and uncalibrated pressure waveform devices

    OpenAIRE

    Monnet, Xavier; Anguel, Nadia; Naudin, Brice; Jabot, Julien; Richard, Christian; Teboul, Jean-Louis

    2010-01-01

    Introduction We compared the ability of two devices estimating cardiac output from arterial pressure-curve analysis to track the changes in cardiac output measured with transpulmonary thermodilution induced by volume expansion and norepinephrine in sepsis patients. Methods In 80 patients with septic circulatory failure, we administered volume expansion (40 patients) or introduced/increased norepinephrine (40 patients). We measured the pulse contour-derived cardiac index (CI) provided by the P...

  6. Parameters of the center of pressure displacement on the saddle during hippotherapy on different surfaces.

    Science.gov (United States)

    Flores, Fabiana M; Dagnese, Frederico; Mota, Carlos B; Copetti, Fernando

    2015-01-01

    Hippotherapy uses horseback riding movements for therapeutic purposes. In addition to the horse's movement, the choice of equipment and types of floor are also useful in the intervention. The quantification of dynamic parameters that define the interaction of the surface of contact between horse and rider provides insight into how the type of floor surface variations act upon the subject's postural control. To test whether different types of surfaces promote changes in the amplitude (ACOP) and velocity (VCOP) of the center of pressure (COP) displacement during the rider's contact with the saddle on the horse's back. Twenty two healthy adult male subjects with experience in riding were evaluated. The penetration resistances of asphalt, sand and grass surfaces were measured. The COP data were collected on the three surfaces using a pressure measurement mat. ACOP values were higher in sand, followed by grass and asphalt, with significant differences between sand and asphalt (anteroposterior, p=0.042; mediolateral, p=0.019). The ACOP and VCOP values were higher in the anteroposterior than in the mediolateral direction on all surfaces (ACOP, p=0.001; VCOP, p=0.006). The VCOP did not differ between the surfaces. Postural control, measured by the COP displacement, undergoes variations in its amplitude as a result of the type of floor surface. Therefore, these results reinforce the importance of the choice of floor surface when defining the strategy to be used during hippotherapy intervention.

  7. Parameters of the center of pressure displacement on the saddle during hippotherapy on different surfaces

    Directory of Open Access Journals (Sweden)

    Fabiana M. Flores

    2015-06-01

    Full Text Available Background: Hippotherapy uses horseback riding movements for therapeutic purposes. In addition to the horse's movement, the choice of equipment and types of floor are also useful in the intervention. The quantification of dynamic parameters that define the interaction of the surface of contact between horse and rider provides insight into how the type of floor surface variations act upon the subject's postural control. Objective: To test whether different types of surfaces promote changes in the amplitude (ACOP and velocity (VCOP of the center of pressure (COP displacement during the rider's contact with the saddle on the horse's back. Method: Twenty two healthy adult male subjects with experience in riding were evaluated. The penetration resistances of asphalt, sand and grass surfaces were measured. The COP data were collected on the three surfaces using a pressure measurement mat. Results: ACOP values were higher in sand, followed by grass and asphalt, with significant differences between sand and asphalt (anteroposterior, p=0.042; mediolateral, p=0.019. The ACOP and VCOP values were higher in the anteroposterior than in the mediolateral direction on all surfaces (ACOP, p=0.001; VCOP, p=0.006. The VCOP did not differ between the surfaces. Conclusion: Postural control, measured by the COP displacement, undergoes variations in its amplitude as a result of the type of floor surface. Therefore, these results reinforce the importance of the choice of floor surface when defining the strategy to be used during hippotherapy intervention.

  8. Saturation in nuclei

    CERN Document Server

    Lappi, T

    2010-01-01

    This talk discusses some recent studies of gluon saturation in nuclei. We stress the connection between the initial condition in heavy ion collisions and observables in deep inelastic scattering (DIS). The dominant degree of freedom in the small x nuclear wavefunction is a nonperturbatively strong classical gluon field, which determines the initial condition for the glasma fields in the initial stages of a heavy ion collision. A correlator of Wilson lines from the same classical fields, known as the dipole cross section, can be used to compute many inclusive and exclusive observables in DIS.

  9. Variation in intraocular pressure following application of tropicamide in three different dog breeds.

    Science.gov (United States)

    Taylor, Nicole R; Zele, Andrew J; Vingrys, Algis J; Stanley, Robin G

    2007-01-01

    To record intraocular pressure (IOP) of three different dog breeds following administration of one drop of 1% tropicamide. Three dog breeds -- Golden Retrievers (n = 20), Siberian Huskies (n = 20) and English Cocker Spaniels (n = 36) -- were studied. IOPs were measured using a Tonopen following corneal anesthesia with a single drop of 0.5% proxymetacaine. A drop of 0.5% tropicamide was then administered bilaterally and a second IOP measurement was taken 30 min later (postdilation). The difference between the two measurements was considered as the effect of mydriasis on IOP. Dogs had an average IOP of 14.9 +/- 3.2 mmHg, with 95% confidence limits ranging from 8 to 22 mmHg. There were significant differences between breeds (P tropicamide of canine IOP is evident.

  10. Pressure distribution evaluation of different filling methods for deposition of powders in dies: Measurement and modeling

    Science.gov (United States)

    Sayyar Roudsari, Saed

    The aim of this research was to measure, analyze, and model the pressure distribution characteristics of powder deposition into rectangular and circular shallow dies using four filling methods. The feed shoe, the rotational rainy, the point feed, and the pneumatic filling methods were used to investigate the deposition characteristics into shallow dies. In order to evaluate the pressure distribution during filling of shallow dies, factors influencing powder deposition were studied. The factors included particle size and shape, particle size distribution, feed shoe speed, and tube cross-section (in case of feed shoe filling) and deposition rates (in case of rotational rainy, point feed, and pneumatic filling). A battery powder mixture (BPM) and microcrystalline cellulose (Avicel PH102) with median size of 84 and 600mum, respectively, were used to fill a shallow rectangular die 32x30 mm and 6.5 mm deep and a shallow circular die 35 mm in diameter and 6.5 mm deep. The second generation of pressure deposition tester (PDT-II) with circular and square feed shoe tube cross-sections was used to measure the two powders' pressure distribution characteristics. An innovative rotational rainy filling device was designed and fabricated. This versatile device can be used to measure filling characteristics at different rotational speeds (1-10 rpm) for various powders. The point feed (funnel fill) method with a funnel of 30 mm inlet diameter and 4.2 mm outlet diameter opening was used to fill the rectangular and circular shallow dies. The pneumatic filling method was designed and fabricated to fill the die using air as the conveying medium in a rectangular cross-section tube. The pneumatic filling device was limited to using only the BPM powder, since the Avicel powder generated substantial quantity of airborne dust during the test. Symmetry analysis, variance metrics, and uniformity analysis were used to quantify the deposition characteristics. The results showed that: (1) filled

  11. Differences in quantitative characteristics of intracranial pressure in hydrocephalic children treated surgically or conservatively.

    Science.gov (United States)

    Eide, Per Kristian; Due-Tønnessen, Bernt; Helseth, Eirik; Lundar, Tryggve

    2002-06-01

    This study reports the results of quantitative analysis of continuous intracranial pressure (ICP) recordings in 33 hydrocephalic children. The aim of the study was to compare the exact numbers of increases in ICP during sleep or the awake state in hydrocephalic children who were treated either surgically or conservatively. At the time of ICP monitoring, the ICP curves were assessed by the calculation of mean ICP and visual inspection for the detection of plateau waves. Quantitative analysis was performed with the software Sensometrics Pressure Analyser, which presented the ICP curve as a matrix of numbers of ICP elevations of different levels (20-40 mm Hg) and durations (0.5-20 min). In each case, the numbers of ICP elevations were standardized to 10 h of recording time, providing the opportunity for comparisons of ICP curves between individuals. Compared to the surgery group, there was a rather high number of ICP elevations of 20 mm Hg of various durations in the nonsurgery group, e.g. ICP elevations of 20 mm Hg lasting 10 min occurred in 13 of 19 children (68%) in the nonsurgery group. There was no apparent relationship between ICP and age or between the size of the cerebral ventricles and ICP. In children with hydrocephalus, the presentation of the ICP data as a matrix of ICP elevations of different levels and durations may enhance the informative value of continuous ICP monitoring, as compared to the calculation of mean ICP and visual detection of plateau waves. Copyright 2002 S. Karger AG, Basel

  12. Effect of different flooring systems on weight and pressure distribution on claws of dairy cows.

    Science.gov (United States)

    Telezhenko, E; Bergsten, C; Magnusson, M; Ventorp, M; Nilsson, C

    2008-05-01

    Weight and pressure distribution on the claw were studied in Swedish Holsteins housed in different flooring systems. A total of 127 cows housed in different sections of the experimental barn were used. Each section had different flooring in the walking and standing areas. There were rubber mats or abrasive mastic asphalt flooring on the alleys or a low-abrasive slatted concrete floor. Some sections had feed-stalls equipped with rubber mats; other sections did not. The vertical ground reaction force, contact area, and average contact pressure were determined on the left hind foot using the I-Scan system and analyzed with the F-scan system. These determinations were made in each of the following 3 zones of the claw: bulb, wall, and sole. Most of the weight on claws exposed to concrete floors was carried by the bulb (37.4 +/- 3.5 and 18.3 +/- 2.9% of weight exerted on the foot in the lateral and medial claw, respectively) and the wall zone (20.0 +/- 2.6 and 13.4 +/- 2.4% on lateral and medial claw, respectively). The weight and pressure distribution in cows kept on sections with rubber covered alleys but passing daily over the asphalt floor on their way to the milking parlor did not differ in any zones, except for lateral bulbs, compared with those exposed to slatted concrete alone. Still, the weight bearing of the sole zone in cows kept on rubber mats without access to asphalt was less than that of cows kept on concrete slatted floors (5.1 +/- 0.7 vs. 12.7 +/- 1.1% and 1.1 +/- 0.5 vs. 8.7 +/- 0.7% in lateral and medial claws, respectively). In cows kept on asphalt flooring without feed-stalls, most weight was exerted to the sole zone (36.2 +/- 2.9 and 22.2 +/- 1.8% in lateral and medial claws, respectively). Feed-stalls in combination with asphalt flooring yielded a decreased total contact area (30.1 +/- 1.2 cm(2)) compared with asphalt floors without feed-stalls (35.7 +/- 1.2 cm(2)). The largest total contact area was obtained on the asphalt floor without feed

  13. Assessing intravascular volume by difference in pulse pressure in pigs submitted to graded hemorrhage.

    Science.gov (United States)

    Pestel, Gunther J; Hiltebrand, Luzius B; Fukui, Kimiko; Cohen, Delphine; Hager, Helmut; Kurz, Andrea M

    2006-10-01

    We assessed changes in intravascular volume monitored by difference in pulse pressure (dPP%) after stepwise hemorrhage in an experimental pig model. Six pigs (23-25 kg) were anesthetized (isoflurane 1.5 vol%) and mechanically ventilated to keep end-tidal CO2 (etCO2) at 35 mmHg. A PA-catheter and an arterial catheter were placed via femoral access. During and after surgery, animals received lactated Ringer's solution as long as they were considered volume responders (dPP>13%). Then animals were allowed to stabilize from the induction of anesthesia and insertion of catheters for 30 min. After stabilization, baseline measurements were taken. Five percent of blood volume was withdrawn, followed by another 5%, and then in 10%-increments until death from exsanguination occurred. After withdrawal of 5% of blood volume, all pigs were considered volume responders (dPP>13%); dPP rose significantly from 6.1+/-3.3% to 19.4+/-4.2%. The regression analysis of stepwise hemorrhage revealed a linear relation between blood loss (hemorrhage in %) and dPP (y=0.99*x+14; R2=0.7764; P<.0001). In addition, dPP was the only parameter that changed significantly between baseline and a blood loss of 5% (P<0.01), whereas cardiac output, stroke volume, heart rate, MAP, central venous pressure, pulmonary artery occlusion pressure, and systemic vascular resistance, respectively, remained unchanged. We conclude that in an experimental hypovolemic pig model, dPP correlates well with blood loss.

  14. Investigation of the kinetics of water uptake into partially saturated shales

    National Research Council Canada - National Science Library

    Roshan, H; Andersen, M. S; Rutlidge, H; Marjo, C. E; Acworth, R. I

    2016-01-01

    .... This study describes novel hydraulic experiments to quantitatively investigate the kinetics of water uptake into partially saturated shale through investigating the pressure response of injecting fluids...

  15. Determination of viscous pressure losssand resistance upstream from the choke point from breathing gases of different physical properties

    DEFF Research Database (Denmark)

    Pedersen, O.F.

    2007-01-01

      Determination of viscous pressure loss and resistance upstream from the choke point from breathing gases of different physical properties Ole F. Pedersen, Institute of Public Health, University of Aarhus, Denmark. AIM. To determine viscous pressure losses and resistances  upstream to CP...

  16. Prediction of Three-Dimensional Downward Flame Spread Characteristics over Poly(methyl methacrylate) Slabs in Different Pressure Environments.

    Science.gov (United States)

    Zhao, Kun; Zhou, Xiao-Dong; Liu, Xue-Qiang; Lu, Lei; Wu, Zhi-Bo; Peng, Fei; Ju, Xiao-Yu; Yang, Li-Zhong

    2016-11-22

    The present study is aimed at predicting downward flame spread characteristics over poly(methyl methacrylate) (PMMA) with different sample dimensions in different pressure environments. Three-dimensional (3-D) downward flame spread experiments on free PMMA slabs were conducted at five locations with different altitudes, which provide different pressures. Pressure effects on the flame spread rate, profile of pyrolysis front and flame height were analyzed at all altitudes. The flame spread rate in the steady-state stage was calculated based on the balance on the fuel surface and fuel properties. Results show that flame spread rate increases exponentially with pressure, and the exponent of pressure further shows an increasing trend with the thickness of the sample. The angle of the pyrolysis front emerged on sample residue in the width direction, which indicates a steady-burning stage, varies clearly with sample thicknesses and ambient pressures. A global non-dimensional equation was proposed to predict the variation tendency of the angle of the pyrolysis front with pressure and was found to fit well with the measured results. In addition, the dependence of average flame height on mass burning rate, sample dimension and pressure was proposed based on laminar diffusion flame theory. The fitted exponent of experimental data is 1.11, which is close to the theoretical value.

  17. Comparison of Different Turbulence Models for Numerical Simulation of Pressure Distribution in V-Shaped Stepped Spillway

    Directory of Open Access Journals (Sweden)

    Zhaoliang Bai

    2017-01-01

    Full Text Available V-shaped stepped spillway is a new shaped stepped spillway, and the pressure distribution is quite different from that of the traditional stepped spillway. In this paper, five turbulence models were used to simulate the pressure distribution in the skimming flow regimes. Through comparing with the physical value, the realizable k-ε model had better precision in simulating the pressure distribution. Then, the flow pattern of V-shaped and traditional stepped spillways was given to illustrate the unique pressure distribution using realizable k-ε turbulence model.

  18. Application and Comparison of Different Combustion Models of High Pressure LOX/CH4 Jet Flames

    Directory of Open Access Journals (Sweden)

    Maria Grazia De Giorgi

    2014-01-01

    Full Text Available The present work focuses on the numerical modeling of combustion in liquid-propellant rocket engines. Pressure and temperature are well above thermodynamic critical points of both the propellants and then the reactants show liquid-like characteristics of density and gas-like characteristics for diffusivity. The aim of the work is an efficient numerical description of the phenomena and RANS simulations were performed for this purpose. Hence, in the present work different kinetics, combustion models and thermodynamic approaches were used for combustion modeling first in a trans-critical environment, then in the sub-critical state. For phases treatment the pure Eulerian single phase approach was compared with the Lagrangian/Eulerian description. For modeling combustion, the Probability Density Function (PDF equilibrium and flamelet approaches and the Eddy Dissipation approach, with two different chemical kinetic mechanisms (the Jones-Lindstedt and the Skeletal model, were used. Real Gas (Soave-Redlich-Kwong and Peng-Robinson equations were applied. To estimate the suitability of different strategies in phenomenon description, a comparison with experimental data from the literature was performed, using the results for different operative conditions of the Mascotte test bench: trans-critical and subcritical condition for oxygen injection. The main result of this study is the individuation of the DPM approach of the most versatile methods to reproduce cryogenic combustion adapted for different operating conditions and producing good results.

  19. Geographic variation of melanisation patterns in a hornet species: genetic differences, climatic pressures or aposematic constraints?

    Science.gov (United States)

    Perrard, Adrien; Arca, Mariangela; Rome, Quentin; Muller, Franck; Tan, Jiangli; Bista, Sanjaya; Nugroho, Hari; Baudoin, Raymond; Baylac, Michel; Silvain, Jean-François; Carpenter, James M; Villemant, Claire

    2014-01-01

    Coloration of stinging insects is often based on contrasted patterns of light and black pigmentations as a warning signal to predators. However, in many social wasp species, geographic variation drastically modifies this signal through melanic polymorphism potentially driven by different selective pressures. To date, surprisingly little is known about the geographic variation of coloration of social wasps in relation to aposematism and melanism and to genetic and developmental constraints. The main objectives of this study are to improve the description of the colour variation within a social wasp species and to determine which factors are driving this variation. Therefore, we explored the evolutionary history of a polymorphic hornet, Vespa velutina Lepeletier, 1836, using mitochondrial and microsatellite markers, and we analysed its melanic variation using a colour space based on a description of body parts coloration. We found two main lineages within the species and confirmed the previous synonymy of V. auraria Smith, 1852, under V. velutina, differing only by the coloration. We also found that the melanic variation of most body parts was positively correlated, with some segments forming potential colour modules. Finally, we showed that the variation of coloration between populations was not related to their molecular, geographic or climatic differences. Our observations suggest that the coloration patterns of hornets and their geographic variations are determined by genes with an influence of developmental constraints. Our results also highlight that Vespa velutina populations have experienced several convergent evolutions of the coloration, more likely influenced by constraints on aposematism and Müllerian mimicry than by abiotic pressures on melanism.

  20. Geographic variation of melanisation patterns in a hornet species: genetic differences, climatic pressures or aposematic constraints?

    Directory of Open Access Journals (Sweden)

    Adrien Perrard

    Full Text Available Coloration of stinging insects is often based on contrasted patterns of light and black pigmentations as a warning signal to predators. However, in many social wasp species, geographic variation drastically modifies this signal through melanic polymorphism potentially driven by different selective pressures. To date, surprisingly little is known about the geographic variation of coloration of social wasps in relation to aposematism and melanism and to genetic and developmental constraints. The main objectives of this study are to improve the description of the colour variation within a social wasp species and to determine which factors are driving this variation. Therefore, we explored the evolutionary history of a polymorphic hornet, Vespa velutina Lepeletier, 1836, using mitochondrial and microsatellite markers, and we analysed its melanic variation using a colour space based on a description of body parts coloration. We found two main lineages within the species and confirmed the previous synonymy of V. auraria Smith, 1852, under V. velutina, differing only by the coloration. We also found that the melanic variation of most body parts was positively correlated, with some segments forming potential colour modules. Finally, we showed that the variation of coloration between populations was not related to their molecular, geographic or climatic differences. Our observations suggest that the coloration patterns of hornets and their geographic variations are determined by genes with an influence of developmental constraints. Our results also highlight that Vespa velutina populations have experienced several convergent evolutions of the coloration, more likely influenced by constraints on aposematism and Müllerian mimicry than by abiotic pressures on melanism.

  1. Gender difference and economic gradients in the secular trend of population systolic blood pressure

    DEFF Research Database (Denmark)

    Andersen, Ulla; Jensen, Gorm B

    2013-01-01

    To a large extent population blood pressure (PBP) affects morbidity and mortality in the society. Reports indicated that PBP decreased in many western countries. The associations between the main cardiovascular risk factors and the changing PBP have been described. The aim of this study was to in......To a large extent population blood pressure (PBP) affects morbidity and mortality in the society. Reports indicated that PBP decreased in many western countries. The associations between the main cardiovascular risk factors and the changing PBP have been described. The aim of this study...... was to investigate association between income factors and trends in population BP and hypertension. Copenhagen City Heart Study is a prospective longitudinal epidemiological study on almost 20000 individuals through four surveys from 1976 to 2003. The BP measurement was fully standardised. Questionnaires...... on household income and CV risk factors were completed by the participants. After adjustment for cardiovascular risk factors there were no significant differences in systolic BP (SBP) trend associated to income among men. Among women, however, there was a reverse relationship between SBP and income...

  2. Resistance exercise with different volumes: blood pressure response and forearm blood flow in the hypertensive elderly

    Directory of Open Access Journals (Sweden)

    Brito AF

    2014-12-01

    Full Text Available Aline de Freitas Brito,1 Caio Victor Coutinho de Oliveira,2 Maria do Socorro Brasileiro-Santos,1 Amilton da Cruz Santos1 1Physical Education Department, 2Research Laboratory for Physical Training Applied to Performance and Health, Federal University of Paraíba, João Pessoa, Brazil Background: The purpose of this study was to evaluate the effect of two sessions of resistance exercise with different volumes on post-exercise hypotension, forearm blood flow, and forearm vascular resistance in hypertensive elderly subjects.Methods: The study was conducted with ten hypertensive elderly (65±3 years, 28.7±3 kg/m2 subjected to three experimental sessions, ie, a control session, exercise with a set (S1, and exercise with three sets (S3. For each session, the subjects were evaluated before and after intervention. In the pre-intervention period, blood pressure, forearm blood flow, and forearm vascular resistance were measured after 10 minutes of rest in the supine position. Thereafter, the subjects were taken to the gym to perform their exercise sessions or remained at rest during the same time period. Both S1 and S3 comprised a set of ten repetitions of ten exercises, with an interval of 90 seconds between exercises. Subsequently, the measurements were again performed at 10, 30, 50, 70, and 90 minutes of recovery (post-intervention in the supine position.Results: Post-exercise hypotension was greater in S3 than in S1 (systolic blood pressure, −26.5±4.2 mmHg versus −17.9±4.7 mmHg; diastolic blood pressure, −13.8±4.9 mmHg versus −7.7±5 mmHg, P<0.05. Similarly, forearm blood flow and forearm vascular resistance changed significantly in both sessions with an increase and decrease, respectively, that was more evident in S3 than in S1 (P<0.05.Conclusion: Resistance exercises with higher volume were more effective in causing post-exercise hypotension, being accompanied by an increase in forearm blood flow and a reduction of forearm vascular

  3. Footprints of spontaneous fluid redistribution on capillary pressure in porous rock

    Science.gov (United States)

    Helland, Johan Olav; Friis, Helmer André; Jettestuen, Espen; Skjæveland, Svein M.

    2017-05-01

    Pore-scale imaging of two-phase flow in porous media shows that pore filling occurs as cooperative events with accompanying spontaneous fluid redistribution in other parts of the pore space. We present a level set method that controls saturation quasi-statically to model experiments controlled by low, constant flow rates and demonstrate that our method can describe the observed displacement mechanisms. The level set approach determines states of capillary equilibrium, which generally are different for displacement protocols constrained by saturation and pressure. Saturation-controlled simulations of drainage in sandstone show spontaneous fluid redistributions with abrupt pressure jumps and cooperative behavior, including snap-off and interface retraction events, consistent with experimental observations. Drainage capillary pressure curves are lower when saturation, rather than pressure, controls displacement. Remarkably, these effects are less significant for imbibition processes where the development of hydraulically connected wetting phase moderates the cooperative behavior and associated pressure jumps.

  4. Determinants of racial/ethnic differences in blood pressure management among hypertensive patients

    Directory of Open Access Journals (Sweden)

    Shaykevich Shimon

    2005-06-01

    Full Text Available Abstract Background Prior literature has shown that racial/ethnic minorities with hypertension may receive less aggressive treatment for their high blood pressure. However, to date there are few data available regarding the confounders of racial/ethnic disparities in the intensity of hypertension treatment. Methods We reviewed the medical records of 1,205 patients who had a minimum of two hypertension-related outpatient visits to 12 general internal medicine clinics during 7/1/01-6/30/02. Using logistic regression, we determined the odds of having therapy intensified by patient race/ethnicity after adjustment for clinical characteristics. Results Blacks (81.9% and Whites (80.3% were more likely than Latinos (71.5% to have therapy intensified (P = 0.03. After adjustment for racial differences in the number of outpatient visits and presence of diabetes, there were no racial differences in rates of intensification. Conclusion We found that racial/ethnic differences in therapy intensification were largely accounted for by differences in frequency of clinic visits and in the prevalence of diabetes. Given the higher rates of diabetes and hypertension related mortality among Hispanics in the U.S., future interventions to reduce disparities in cardiovascular outcomes should increase physician awareness of the need to intensify drug therapy more agressively in patients without waiting for multiple clinic visits, and should remind providers to treat hypertension more aggressively among diabetic patients.

  5. Antioxidant White Grape Seed Phenolics: Pressurized Liquid Extracts from Different Varieties

    Directory of Open Access Journals (Sweden)

    Carmen Garcia-Jares

    2015-11-01

    Full Text Available Grape seeds represent a high percentage (20% to 26% of the grape marc obtained as a byproduct from white winemaking and keep a vast proportion of grape polyphenols. In this study, seeds obtained from 11 monovarietal white grape marcs cultivated in Northwestern Spain have been analyzed in order to characterize their polyphenolic content and antioxidant activity. Seeds of native (Albariño, Caiño, Godello, Loureiro, Torrontés, and Treixadura and non-native (Chardonnay, Gewurtzträminer, Pinot blanc, Pinot gris, and Riesling grape varieties have been considered. Low weight phenolics have been extracted by means of pressurized liquid extraction (PLE and further analyzed by LC-MS/MS. The results showed that PLE extracts, whatever the grape variety of origin, contained large amounts of polyphenols and high antioxidant activity. Differences in the varietal polyphenolic profiles were found, so a selective exploitation of seeds might be possible.

  6. Investigation of the surface free energy of the ITO thin films deposited under different working pressure

    Energy Technology Data Exchange (ETDEWEB)

    Özen, Soner, E-mail: osoner@ogu.edu.tr; Pat, Suat; Korkmaz, Şadan [Eskişehir Osmangazi University, Physics Department, 26480 (Turkey); Şenay, Volkan [Eskişehir Osmangazi University, Physics Department, 26480 (Turkey); Bayburt University, Primary Science Education Department, 69000 (Turkey)

    2016-03-25

    This study discusses the influence of working pressure on the surface energy of the ITO thin films produced by radio frequency magnetron sputtering method. Optical tensiometer (Attension Theta Lite) is used for evaluating wetting behavior of the water droplet on the film surface and Equation of State method was selected to determine surface free energy for this study. Equation of state method does not divide the surface tension into different components such as polar, dispersive, acid-base. It is calculated the surfaces’ free energy measuring the contact angle with a single liquid. The surface free energy value was in the range of 15-31 mN/m. Also, the transmittances were determined in the wavelength range between 200 and 1000 nm using the UNICO 4802 UV-Vis double beam spectrophotometer. Transmittances of the produced ITO thin films are greater than %70 in the visible range.

  7. Persuader sex differences and peer pressure effects on attitudes toward drug abuse.

    Science.gov (United States)

    Stone, C I; Shute, R E

    1977-01-01

    This experiment was performed to assess the effects of the experimental confederates' sex and contrived group peer pressure on the drug attitudes of male college students. Subjects were exposed to all-male or all-female groups of experimental confederates (ersuaders) who expressed either extremely pro-drug or anti-drug sentiments in a guided group discussion. A drug attitude survey encompassing four drug categories was administered immediately following the discussion. Significant differences were found between subjects in the anti-drug and pro-drug groups. The sex effect data indicated that the male subjects reported more liberal drug attitudes following exposure to female persuaders in both the anti-and pro-drug treatment conditions for the more socially acceptable drugs such as marijuana, hashish, and stimulants. Implications of these findings for possible prevention and intervention strategies and for further research are discussed.

  8. Transvalvular pressure gradients for different methods of mitral valve repair: only neochordoplasty achieves native valve gradients.

    Science.gov (United States)

    Jahren, Silje Ekroll; Hurni, Samuel; Heinisch, Paul Philipp; Winkler, Bernhard; Obrist, Dominik; Carrel, Thierry; Weber, Alberto

    2018-02-01

    Many surgical and interventional methods are available to restore patency for patients with degenerative severe mitral valve regurgitation. Leaflet resection and neochordoplasty, which both include ring annuloplasty, are the most frequently performed techniques for the repair of posterior mitral leaflet flail. It is unclear which technique results in the best haemodynamics. In this study, we investigated the effect of different mitral valve reconstruction techniques on mitral valve haemodynamics and diastolic transvalvular pressure gradient in an ex vivo porcine model. Eight porcine mitral valves were tested under pulsatile flow conditions in an in vitro pulsatile flow loop for haemodynamic quantification. Severe acute posterior mitral leaflet flail was created by resecting the posterior marginal chorda. The acute mitral valve regurgitation was corrected using 4 different repair techniques, in each valve, in a strictly successive order: (i) neochordoplasty with polytetrafluoroethylene sutures alone and (ii) with ring annuloplasty, (iii) edge-to-edge repair and (iv) triangular leaflet resection, both with ring annuloplasty. Valve haemodynamics were measured and quantified for all valve configurations (native, rupture and each surgical reconstruction). The results were analysed using a validated statistical linear mixed model, and the P-values were calculated using a 2-sided Wald test. All surgical reconstruction techniques were able to sufficiently correct the acute mitral valve regurgitation. Neochordoplasty without ring annuloplasty was the only reconstruction technique that resulted in haemodynamic properties similar to the native mitral valve (P-values from 0.071 to 0.901). The diastolic transvalvular gradient remained within the physiological range for all reconstructions but was significantly higher than in the native valve for neochordoplasty with ring annuloplasty (P < 0.000), edge-to-edge repair (P < 0.000) and leaflet resection (P < 0

  9. Investigation of absolute and relative response for three different liquid chromatography/tandem mass spectrometry systems; the impact of ionization and detection saturation.

    Science.gov (United States)

    Nilsson, Lars B; Skansen, Patrik

    2012-06-30

    The investigations in this article were triggered by two observations in the laboratory; for some liquid chromatography/tandem mass spectrometry (LC/MS/MS) systems it was possible to obtain linear calibration curves for extreme concentration ranges and for some systems seemingly linear calibration curves gave good accuracy at low concentrations only when using a quadratic regression function. The absolute and relative responses were tested for three different LC/MS/MS systems by injecting solutions of a model compound and a stable isotope labeled internal standard. The analyte concentration range for the solutions was 0.00391 to 500 μM (128,000×), giving overload of the chromatographic column at the highest concentrations. The stable isotope labeled internal standard concentration was 0.667 μM in all samples. The absolute response per concentration unit decreased rapidly as higher concentrations were injected. The relative response, the ratio for the analyte peak area to the internal standard peak area, per concentration unit was calculated. For system 1, the ionization process was found to limit the response and the relative response per concentration unit was constant. For systems 2 and 3, the ion detection process was the limiting factor resulting in decreasing relative response at increasing concentrations. For systems behaving like system 1, simple linear regression can be used for any concentration range while, for systems behaving like systems 2 and 3, non-linear regression is recommended for all concentration ranges. Another consequence is that the ionization capacity limited systems will be insensitive to matrix ion suppression when an ideal internal standard is used while the detection capacity limited systems are at risk of giving erroneous results at high concentrations if the matrix ion suppression varies for different samples in a run. Copyright © 2012 John Wiley & Sons, Ltd.

  10. Large eddy simulation of zero-pressure-gradient turbulent boundary layer based on different scaling laws

    Science.gov (United States)

    Cheng, Wan; Samtaney, Ravi

    2013-11-01

    We present results of large eddy simulation (LES) for a smooth-wall, zero-pressure-gradient turbulent boundary layer. We employ the stretched vortex sub-grid-scale model in the simulations augmented by a wall model. Our wall model is based on the virtual-wall model introduced by Chung & Pullin (J. Fluid Mech 2009). An essential component of their wall model is an ODE governing the local wall-normal velocity gradient obtained using inner-scaling ansatz. We test two variants of the wall model based on different similarity laws: one is based on a log-law and the other on a power-law. The specific form of the power law scaling utilized is that proposed by George & Castillo (Appl. Mech. Rev. 1997), dubbed the ``GC Law''. Turbulent inflow conditions are generated by a recycling method, and applying scaling laws corresponding to the two variants of the wall model, and a uniform way to determine the inlet friction velocity. For Reynolds number based on momentum thickness, Reθ , ranging from 104 to 1012 it is found that the velocity profiles generally follow the log law form rather than the power law. For large Reynolds number asymptotic behavior, LES based on different scaling laws the boundary layer thickness and turbulent intensities do not show much difference. Supported by a KAUST funded project on large eddy simulation of turbulent flows. The IBM Blue Gene P Shaheen at KAUST was utilized for the simulations.

  11. HEART FREQUENCY AND BLOOD PRESSURE IN DIFFERENT LOADS IN ERGOMETER STEP (CIRILO IN ACTIVE WOMEN

    Directory of Open Access Journals (Sweden)

    Maria do Socorro Cirilo de Sousa

    2005-08-01

    Full Text Available The objective of the study was to analyze the behavior of Heart Rate and Blood Pressure in different loads in step test. Methodology: It was an applied, transversal, analytical, not- probabilist research. The sample consisted of 5 active women, average of age 22,8 (SD=2,8. The test was applied in four consecutive days with progressivity of loads. It was measured hight (cm, body weight (kg, HR and BP. It used statistics of average, standard desviation, test "t" of Student, Friedman and "r" of Pearson. Confidence level 5%. Results: It was found significant differences for HR and BP of 1st 4th load (p=0,000, between BP and HR of rest and effort (p=0,000. It had correlations raised for the DBP of rest and effort of 1st and 4th day. Conclusions: HR and BP, in accordance with present different the time of execution of test indicating that it has alterations in the behavior of hemodinâmic variables.

  12. Gender differences in athlete's heart: association with 24-h blood pressure. A study of pairs in sport dancing.

    Science.gov (United States)

    Zemva, A; Rogel, P

    2001-01-01

    Long term athletic training is associated with an increase in left ventricular diastolic cavity dimensions, wall thickness, and mass. These changes are described as the "athlete's heart". In comparison to men, athletic training in women athletes is not a stimulus for substantial increase in left ventricular wall thickness. Although many variables are related to these gender differences in cardiac morphology, some factors such as 24-h blood pressure and the level of training have not been studied yet. Therefore pairs in sport dancing, in which the level of training of both partners is the same, were chosen as models in order to evaluate whether 24-h blood pressure contributes to sex-related differences in an athlete's heart. Fifteen pairs in the national sport dancing team and 30 control subjects (15 males, 15 females) were studied. In all subjects casual and 24-h ambulatory blood pressures, echocardiography, and maximal stress testing were performed. Female in comparison to male dancers had significantly lower M-mode (P<0.004) and 2-D left ventricular mass index (P<0.001), 24-h systolic blood pressure (P<0.003), day systolic blood pressure (P<0.002), casual systolic blood pressure (P<0.025), and achieved significantly lower peak systolic blood pressure at stress testing (P<0.004). Multiple stepwise regression analysis showed that the best predictors of 2-D left ventricular mass index are maximal work load and peak exercise systolic blood pressure, 24-h systolic blood pressure, day, and casual systolic blood pressure. Lower left ventricular mass index in female dancers can be partly explained by lower systolic blood pressures during 24-h and at exercise.

  13. Skin perfusion pressure measured by isotope washout in legs with arterial occlusive disease. Evaluation of different tracers, comparison to segmental systolic pressure, angiography and transcutaneous oxygen tension and variations during changes in systemic blood pressure

    DEFF Research Database (Denmark)

    Holstein, P; Trap-Jensen, J; Bagger, H

    1983-01-01

    digit (strain gauge technique). The two different methods correlated statistically significant at all four levels, but the systolic blood pressures were higher than the SPP in particular in diabetic legs; (3) Angiograms in 35 legs with AOD showed that the SPP on the ankle was only consistently decreased......The skin perfusion pressure (SPP) measured as the isotope washout cessation external pressure is valuable in selection of major amputation level. Five methodological investigations important to clinical use were carried out: (1) In five normal legs and 10 legs with arterial occlusive disease (AOD......Hg (range 18-98) (P less than 0.02). The average washout constant for the three different tracers were approximately equal and correlated statistically significant with the SPP; (2) In 59 legs with AOD, segmental SPP was compared to segmental systolic blood pressures on the thigh, calf, ankle and first...

  14. Application of highly sensitive fluorescent dyes (CyDye DIGE Fluor saturation dyes) to laser microdissection and two-dimensional difference gel electrophoresis (2D-DIGE) for cancer proteomics.

    Science.gov (United States)

    Kondo, Tadashi; Hirohashi, Setsuo

    2006-01-01

    Proteome data combined with histopathological information provides important, novel clues for understanding cancer biology and reveals candidates for tumor markers and therapeutic targets. We have established an application of a highly sensitive fluorescent dye (CyDye DIGE Fluor saturation dye), developed for two-dimensional difference gel electrophoresis (2D-DIGE), to the labeling of proteins extracted from laser microdissected tissues. The use of the dye dramatically decreases the protein amount and, in turn, the number of cells required for 2D-DIGE; the cells obtained from a 1 mm2 area of an 8-12 microm thick tissue section generate up to 5,000 protein spots in a large-format 2D gel. This protocol allows the execution of large-scale proteomics in a more efficient, accurate and reproducible way. The protocol can be used to examine a single sample in 5 d or to examine hundreds of samples in large-scale proteomics.

  15. Interaction of an S100A9 gene variant with saturated fat and carbohydrates to modulate insulin resistance in 3 populations of different ancestries.

    Science.gov (United States)

    Blanco-Rojo, Ruth; Delgado-Lista, Javier; Lee, Yu-Chi; Lai, Chao-Qiang; Perez-Martinez, Pablo; Rangel-Zuñiga, Oriol; Smith, Caren E; Hidalgo, Bertha; Alcala-Diaz, Juan F; Gomez-Delgado, Francisco; Parnell, Laurence D; Arnett, Donna K; Tucker, Katherine L; Lopez-Miranda, Jose; Ordovas, Jose M

    2016-08-01

    S100 calcium-binding protein A9 (S100A9) has previously been identified as a type 2 diabetes (T2D) gene. However, this finding requires independent validation and more in-depth analyses in other populations and ancestries. We aimed to replicate the associations between an S100A9 variant and insulin resistance and T2D and to initiate an investigation of potential interactions with the habitual diet in several independent populations. We investigated the association of the S100A9 variant rs3014866 with insulin resistance and T2D risk and its interactions with diet in 3 diverse populations as follows: the CORDIOPREV (Coronary Diet Intervention with Olive Oil and Cardiovascular Prevention; n = 711), which consisted of Spanish white adults; the GOLDN (Genetics of Lipids Lowering Drugs and Diet Network; n = 818), which involved North American non-Hispanic white adults; and Hispanic adults who participated in the BPRHS (Boston Puerto Rican Health Study; n = 1155). Meta-analysis indicated that T carriers presented a lower risk of T2D than CC carriers (pooled OR: 0.714; 95% CI: 0.584, 0.845; P = 0.002). In all 3 populations (CORDIOPREV, GOLDN, and BPRHS), we showed a significant interaction between the rs3014866 single nucleotide polymorphism and dietary SFA:carbohydrate ratio intake for the homeostasis model assessment of insulin resistance (HOMA-IR) (P = 0.028, P = 0.017, and P = 0.026, respectively). CC carriers had a significantly higher HOMA-IR only when SFA:carbohydrate intake was high (P = 0.045 for the CORDIOPREV, P = 0.033 for the GOLDN, and P = 0.046 for the BPRHS) but not when SFA:carbohydrate ratio intake was low. The minor allele (T) of the S100A9 variant rs3014866 is associated with lower T2D risk in 3 populations of different ancestries. Note that individuals with the high-risk CC genotype may be more likely to benefit from a low SFA:carbohydrate ratio intake to improve insulin resistance as evaluated with the use of the HOMA-IR. These trials were registered

  16. Gender difference and economic gradients in the secular trend of population systolic blood pressure.

    Science.gov (United States)

    Andersen, Ulla O; Jensen, Gorm B

    2013-09-01

    To a large extent population blood pressure (PBP) affects morbidity and mortality in the society. Reports indicated that PBP decreased in many western countries. The associations between the main cardiovascular risk factors and the changing PBP have been described. The aim of this study was to investigate association between income factors and trends in population BP and hypertension. Copenhagen City Heart Study is a prospective longitudinal epidemiological study on almost 20000 individuals through four surveys from 1976 to 2003. The BP measurement was fully standardised. Questionnaires on household income and CV risk factors were completed by the participants. After adjustment for cardiovascular risk factors there were no significant differences in systolic BP (SBP) trend associated to income among men. Among women, however, there was a reverse relationship between SBP and income. In addition, there was a trend towards a lowering of risk-factor adjusted SBP in the high income women with time. The mechanism that lies behind the associations between trend in SBP and income is not known but data suggest that poor lifestyle may explain some of the differences. The treated hypertensives are treated without income associated treatment differences. Women in higher income groups have lower SBP than women in low-income groups and the gap between SBP in high-income women and low-income women increased with time. There were no significant differences in SBP-trend associated to income among men. Results in treating hypertension did not differ between the income groups. Copyright © 2013 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

  17. Interankle systolic blood pressure difference and renal outcomes in patients with chronic kidney disease.

    Science.gov (United States)

    Chen, Szu-Chia; Tsai, Yi-Chun; Huang, Jiun-Chi; Lee, Su-Chu; Chang, Jer-Ming; Hwang, Shang-Jyh; Chen, Hung-Chun

    2016-05-01

    Interankle blood pressure (BP) difference has been associated with peripheral artery disease and adverse cardiovascular outcomes. However, the relationship between interankle BP difference and renal outcomes in chronic kidney disease (CKD) has never been evaluated. The purpose of this study was to determine whether interankle BP difference is associated with the rate of renal function decline and progression to renal end points in patients with stage 3-5 CKD. We enrolled 144 patients with CKD from one regional hospital. The BP in four limbs was simultaneously measured using an ABI-form device. The decline in renal function was evaluated using an estimated glomerular filtration rate (eGFR) slope. Rapid renal progression was defined as an eGFR slope < -3 mL/min per 1.73 m(2) per year. The renal end points were defined as ≥ 25% decline in eGFR or commencement of dialysis during the follow-up period. During a mean follow-up period of 3.1 years, 90 patients (62.5%) reached renal end points. Multivariate analysis showed that an increased interankle systolic BP difference (per 5 mmHg) was associated with a worse eGFR slope (regression β, -0.292; 95% confidence interval [CI], -0.482 to -0.102; P = 0.003), rapid renal progression (odds ratio, 1.189; 95% CI, 1.015-1.394; P = 0.032), and an increased risk of progression to renal end points (hazard ratio, 1.126; 95% CI, 1.052-1.204, P = 0.001). Interankle systolic BP difference was associated with rapid renal progression and progression to renal end points in patients with stage 3-5 CKD in our study. © 2015 Asian Pacific Society of Nephrology.

  18. Intraocular pressure measurement by three different tonometers in primary congenital glaucoma

    Directory of Open Access Journals (Sweden)

    Athar Zareei

    2015-01-01

    Full Text Available Purpose: To determine the agreement between intraocular pressure (IOP measurements using an automated non-contact tonometer (NCT, Goldmann applanation tonometer (GAT, and the ocular response analyzer (ORA in subjects with primary congenital glaucoma (PCG. Methods: Twenty-nine eyes of 17 PCG patients underwent IOP measurements using NCT, GAT and ORA. Variables obtained by the ORA were corneal-compensated IOP (IOPcc, Goldmann-correlated IOP (IOPg, corneal hysteresis (CH, and corneal resistance factor (CRF. A difference more than 1.5 mmHg for IOP was considered as clinically relevant. Results: Mean age of the patients was 12 years. Mean IOP (±standard deviation, SD was 15.3 ± 2.8 mmHg (GAT, 15.5 ± 6.0 (NCT, 19.2 ± 7.0 (IOPg, and 21.1 ± 7.9 (IOPcc; (P = 0.001. Except for NCT vs. GAT (P = 1.0, the average IOP difference between each pair of measurements was clinically relevant. The 95% limits of agreements were − 10.2 to 10.3 mmHg (NCT vs. GAT, −7.8 to 15.3 (IOPg vs. GAT, and − 8.1 to 19.0 (IOPcc vs. GAT. The differences in IOP measurements increased significantly with higher average IOP values (r = 0.715, P = 0.001, for NCT vs. GAT; r = 0.802, P < 0.001, for IOPg vs. GAT; and r = 0.806, P < 0.001, for IOPcc vs. GAT. CH showed a significant association with differences in IOP measurements only for IOPcc vs. GAT (r = 0.830, P < 0.001. Conclusion: Mean IOP obtained by NCT was not significantly different from that of GAT, but ORA measured IOPs were significantly higher than both other devices.

  19. Synthetic oligomer analysis using atmospheric pressure photoionization mass spectrometry at different photon energies

    Energy Technology Data Exchange (ETDEWEB)

    Desmazières, Bernard [Global Bioenergies, 5 rue Henri Desbruyeres, 91030 Evry (France); Legros, Véronique [CNRS, UMR8587, Université d’Evry-Val-d’Essonne, Laboratoire Analyse et Modélisation pour la Biologie et l’Environnement, F-91025 Evry (France); Giuliani, Alexandre [Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin, 91192 Gif-sur-Yvette (France); UAR1008, CEPIA, INRA, Rue de la Geraudiere, F-44316 Nantes (France); Buchmann, William, E-mail: william.buchmann@univ-evry.fr [CNRS, UMR8587, Université d’Evry-Val-d’Essonne, Laboratoire Analyse et Modélisation pour la Biologie et l’Environnement, F-91025 Evry (France)

    2014-01-15

    Graphical abstract: Atmospheric pressure photoIonization mass spectra of synthetic oligomers were recorded in the negative mode by varying the photon energy using synchrotron radiation. Photon energy required for an efficient ionization of the polymer was correlated to ionization potential of the solvent (for example 9.4 eV for tetrahydrofuran). -- Highlights: •Atmospheric pressure photoionization was performed using synchrotron radiation. •Photoionization of oligomers in THF with 10% CH{sub 2}Cl{sub 2} produces intact [M + Cl]{sup −} ions. •The photon energy required corresponds to ionization potential of the solvent. •Polymer distributions depend on source parameters such T °C and applied voltages. •Liquid chromatography was coupled to MS using an APPI interface for polymer analysis. -- Abstract: Atmospheric pressure photoionization (APPI) followed by mass spectrometric detection was used to ionize a variety of polymers: polyethylene glycol, polymethyl methacrylate, polystyrene, and polysiloxane. In most cases, whatever the polymer or the solvent used (dichloromethane, tetrahydrofuran, hexane, acetone or toluene), only negative ion mode produced intact ions such as chlorinated adducts, with no or few fragmentations, in contrast to the positive ion mode that frequently led to important in-source fragmentations. In addition, it was shown that optimal detection of polymer distributions require a fine tuning of other source parameters such as temperature and ion transfer voltage. Series of mass spectra were recorded in the negative mode, in various solvents (dichloromethane, tetrahydrofuran, hexane, toluene, and acetone), by varying the photon energy from 8 eV up to 10.6 eV using synchrotron radiation. To these solvents, addition of a classical APPI dopant (toluene or acetone) was not necessary. Courtesy of the synchrotron radiation, it was demonstrated that the photon energy required for an efficient ionization of the polymer was correlated to the

  20. Electrocardiographic, echocardiographic, and indirect blood pressure evaluation in dogs subjected to different sedation protocols

    Directory of Open Access Journals (Sweden)

    Helena Mondardo Cardoso

    Full Text Available ABSTRACT: The present study aimed to evaluate the effects of different sedation protocols on blood pressure and echocardiographic and electrocardiographic parameters in dogs. In total, 24 male mixed-breed dogs with a mean weight of 9.87±3.0kg were used.Animals were randomly divided into four groups (n=6, which were subjected to sedation using the following protocols: acepromazine (0.05mgkg-1 and butorphanol (0.3mgkg-1 (AB; acepromazine (0.05mgkg-1and methadone (0.5mgkg-1 (AM; acepromazine (0.03mgkg-1, methadone (0.5mgkg-1, and midazolam (0.3mgkg-1(MAM; and methadone only (0.5mgkg-1 (M. Indirect blood pressure (BP measurements and computerized electrocardiography (ECG and echocardiography (ECO were performed immediately before the application of the sedation protocol (baseline, and the same evaluations were repeated after 15 minutes. BP decreased in groups AB, MAM, and AM compared to baseline values. Electrocardiographic measurements showed decreased heart rates (HRs after sedation in all groups, and bradycardia was observed after sedation in two dogs from group M and one animal from group AM. The P-wave duration increased after sedation in groups AM and M. After sedation, no changes in cardiac dimensions were revealed byECO.Fractional shortening (FS decreased after sedation in the AM group, and dogs from group AB exhibited a smaller decrease in FS compared with the other groups. The cardiac index (CI was lower in groups AM and M than in the other groups. Animals from group AB were less resistant to examination and exhibited the most favorable sedation scores. It was concluded that the combination of acepromazine and butorphanol was the best sedation protocol for performing echocardiogram measurementsbecause dogs were less resistant to examinations and echocardiographic parameters of FS and CI remained stable.

  1. Association between different measurements of blood pressure variability by ABP monitoring and ankle-brachial index

    Directory of Open Access Journals (Sweden)

    Moreira Leila B

    2010-11-01

    Full Text Available Abstract Background Blood pressure (BP variability has been associated with cardiovascular outcomes, but there is no consensus about the more effective method to measure it by ambulatory blood pressure monitoring (ABPM. We evaluated the association between three different methods to estimate BP variability by ABPM and the ankle brachial index (ABI. Methods and Results In a cross-sectional study of patients with hypertension, BP variability was estimated by the time rate index (the first derivative of SBP over time, standard deviation (SD of 24-hour SBP; and coefficient of variability of 24-hour SBP. ABI was measured with a doppler probe. The sample included 425 patients with a mean age of 57 ± 12 years, being 69.2% women, 26.1% current smokers and 22.1% diabetics. Abnormal ABI (≤ 0.90 or ≥ 1.40 was present in 58 patients. The time rate index was 0.516 ± 0.146 mmHg/min in patients with abnormal ABI versus 0.476 ± 0.124 mmHg/min in patients with normal ABI (P = 0.007. In a logistic regression model the time rate index was associated with ABI, regardless of age (OR = 6.9, 95% CI = 1.1- 42.1; P = 0.04. In a multiple linear regression model, adjusting for age, SBP and diabetes, the time rate index was strongly associated with ABI (P Conclusion Time rate index is a sensible method to measure BP variability by ABPM. Its performance for risk stratification of patients with hypertension should be explored in longitudinal studies.

  2. Association between different measurements of blood pressure variability by ABP monitoring and ankle-brachial index.

    Science.gov (United States)

    Wittke, Estefânia; Fuchs, Sandra C; Fuchs, Flávio D; Moreira, Leila B; Ferlin, Elton; Cichelero, Fábio T; Moreira, Carolina M; Neyeloff, Jeruza; Moreira, Marina B; Gus, Miguel

    2010-11-05

    Blood pressure (BP) variability has been associated with cardiovascular outcomes, but there is no consensus about the more effective method to measure it by ambulatory blood pressure monitoring (ABPM). We evaluated the association between three different methods to estimate BP variability by ABPM and the ankle brachial index (ABI). In a cross-sectional study of patients with hypertension, BP variability was estimated by the time rate index (the first derivative of SBP over time), standard deviation (SD) of 24-hour SBP; and coefficient of variability of 24-hour SBP. ABI was measured with a doppler probe. The sample included 425 patients with a mean age of 57 ± 12 years, being 69.2% women, 26.1% current smokers and 22.1% diabetics. Abnormal ABI (≤ 0.90 or ≥ 1.40) was present in 58 patients. The time rate index was 0.516 ± 0.146 mmHg/min in patients with abnormal ABI versus 0.476 ± 0.124 mmHg/min in patients with normal ABI (P = 0.007). In a logistic regression model the time rate index was associated with ABI, regardless of age (OR = 6.9, 95% CI = 1.1- 42.1; P = 0.04). In a multiple linear regression model, adjusting for age, SBP and diabetes, the time rate index was strongly associated with ABI (P < 0.01). None of the other indexes of BP variability were associated with ABI in univariate and multivariate analyses. Time rate index is a sensible method to measure BP variability by ABPM. Its performance for risk stratification of patients with hypertension should be explored in longitudinal studies.

  3. Comparison of differences in respiratory function and pressure as a predominant abnormal movement of children with cerebral palsy.

    Science.gov (United States)

    Kwon, Hae-Yeon

    2017-02-01

    [Purpose] The purpose of this study was to determine differences in respiratory function and pressure among three groups of children with cerebral palsy as a predominant abnormal movement which included spastic type, dyskinetic type, and ataxic type. [Subjects and Methods] Forty-three children with cerebral palsy of 5-13 years of age in I-III levels according to the Gross Motor Function Classification System, the study subjects were divided by stratified random sampling into three groups of spastic type, dyskinetic type, and ataxic type. For reliability of the measurement results, respiratory function and pressure of the children with cerebral palsy were measured by the same inspector using Spirometer Pony FX (Cosmed Ltd., Italy) equipment, and the subject's guardians (legal representative) was always made to observe. [Results] In the respiratory function, there were significant differences among three groups in all of forced vital capacity, forced expiratory volume at one second, and peak expiratory flow. For respiratory pressure, the maximal inspiratory pressure had significant differences among three groups, although the maximal expiratory pressure had no significant difference. [Conclusion] Therefore, pediatric physical therapists could be provided with important clinical information in understanding the differences in respiratory function and pressure for the children with cerebral palsy showing predominantly abnormal movement as a diverse qualitative characteristics of the muscle tone and movement patterns, and in planning intervention programs for improvement of respiratory capacity.

  4. Investigation of the different base fluid effects on the nanofluids heat transfer and pressure drop

    Science.gov (United States)

    Bayat, Javad; Nikseresht, Amir Hossein

    2011-09-01

    A numerical study of laminar forced convective flows of three different nanofluids through a horizontal circular tube with a constant heat flux condition has been performed. The effect of Al2O3 volume concentration 0 ≤ φ ≤ 0.09 in the pure water, water-ethylene glycol mixture and pure ethylene glycol as base fluids, and Reynolds number of 100 ≤ Re ≤ 2,000 for different power inputs in the range of 10 ≤ Q( W) ≤ 400 have been investigated. In this study, all of the nanofluid properties are temperature and nanoparticle volume concentration dependent. The governing equations have been solved using finite volume approach with the SIMPLER algorithm. The results indicate an increase in the averaged heat transfer coefficient with increasing the mass of ethylene glycol in the water base fluid, solid concentration and Reynolds number. From the investigations it can be inferred that, the pressure drop and pumping power in the nanofluids at low solid volumetric concentration (φ rate with lower wall shear stress with the use of proper nanofluids.

  5. Leukotriene D4 increases pulmonary vascular permeability and pressure by different mechanisms in the rabbit.

    Science.gov (United States)

    Farrukh, I S; Sciuto, A M; Spannhake, E W; Gurtner, G H; Michael, J R

    1986-08-01

    We designed experiments to define the effects of leukotriene D4 (LTD4) in the rabbit lung and to determine whether or not these effects were due to the synthesis of cyclooxygenase products. Infusion of LTD4 (0.01, 0.03, and 0.10 microgram) into the rabbit pulmonary vasculature caused a dose-related increase in pulmonary arterial pressure and tracheal pressure. Pretreatment with FPL 55712 (38 microM), a leukotriene receptor antagonist, or indomethacin (10 micrograms/ml of perfusate) completely prevented the increase in tracheal and pulmonary arterial pressure. We also studied the effect of LTD4 on pulmonary vascular permeability by measuring lung weight gain at 4 levels of left atrial pressures (0, 5, 10, and 15 mmHg). Leukotriene D4 increased lung weight gain at all levels of left atrial pressure compared with that in the control group. Pretreatment with FPL 55712 completely inhibited the increase in vascular permeability caused by LTD4. Although pretreatment with indomethacin blocked the increase in tracheal and vascular pressure caused by LTD4, it did not prevent the increase in vascular permeability. We conclude that in the rabbit, LTD4 increases tracheal pressure, pulmonary arterial pressure, and pulmonary vascular permeability. Leukotriene D4 increases tracheal and pulmonary arterial pressure by stimulating the synthesis of cyclooxygenase products, and it increases vascular permeability through a mechanism that does not require the synthesis of cyclooxygenase products.

  6. Intraocular pressure measurement by three different tonometers in primary congenital glaucoma.

    Science.gov (United States)

    Zareei, Athar; Razeghinejad, Mohammad Reza; Nowroozzadeh, Mohammad Hosein; Mehrabi, Yadollah; Aghazadeh-Amiri, Mohammad

    2015-01-01

    To determine the agreement between intraocular pressure (IOP) measurements using an automated non-contact tonometer (NCT), Goldmann applanation tonometer (GAT), and the ocular response analyzer (ORA) in subjects with primary congenital glaucoma (PCG). Twenty-nine eyes of 17 PCG patients underwent IOP measurements using NCT, GAT and ORA. Variables obtained by the ORA were corneal-compensated IOP (IOPcc), Goldmann-correlated IOP (IOPg), corneal hysteresis (CH), and corneal resistance factor (CRF). A difference more than 1.5 mmHg for IOP was considered as clinically relevant. Mean age of the patients was 12 years. Mean IOP (±standard deviation, SD) was 15.3 ± 2.8 mmHg (GAT), 15.5 ± 6.0 (NCT), 19.2 ± 7.0 (IOPg), and 21.1 ± 7.9 (IOPcc); (P = 0.001). Except for NCT vs. GAT (P = 1.0), the average IOP difference between each pair of measurements was clinically relevant. The 95% limits of agreements were - 10.2 to 10.3 mmHg (NCT vs. GAT), -7.8 to 15.3 (IOPg vs. GAT), and - 8.1 to 19.0 (IOPcc vs. GAT). The differences in IOP measurements increased significantly with higher average IOP values (r = 0.715, P = 0.001, for NCT vs. GAT; r = 0.802, P IOP measurements only for IOPcc vs. GAT (r = 0.830, P IOP obtained by NCT was not significantly different from that of GAT, but ORA measured IOPs were significantly higher than both other devices.

  7. Blood pressure differences between office and home settings among Japanese normotensive subjects and hypertensive patients.

    Science.gov (United States)

    Mori, Hisao; Ukai, Hiroshi; Yamamoto, Hareaki; Yuasa, Shouhei; Suzuki, Yoshiro; Chin, Keiichi; Katsumata, Takuma; Umemura, Satoshi

    2017-03-01

    This study attempted to clarify the differences in blood pressure (BP) between the office (clinic) and home settings in patients with controlled, sustained, masked or white-coat hypertension. The following formula was used: office mean systolic BP (omSBP)-mean morning home SBP (mmhSBP)/office mean diastolic BP (omDBP)-mean morning home DBP (mmhDBP). The paired t-test was used for statistical analysis. The omSBP-mmhSBP/omDBP-mmhDBP calculation yielded the following results: among normotensive subjects, -1.1±11.2/-1.7±8.5 mm Hg (mean SBP and mean DBP were higher at home than in the office; n=451, P=0.038 in SBP, P=0.000 in DBP); in controlled hypertensive patients, -0.42±10.9/-2.2±8.2 mm Hg (n=1362, P=0.160 in SBP, P=0.000 in DBP); among sustained hypertensive patients, 5.6±14.7/0.048±9.9 mm Hg (n=1370, P=0.000 in SBP, P=0.857 in DBP); in masked hypertensive patients, -15.3±12.9/-9.3±9.5 mm Hg (n=1308, both P=0.000); and among white-coat hypertensive patients, 23.7±13.2/8.2±9.1 mm Hg (n=580, both P=0.000). Our results showed a difference of 5 mm Hg in SBP among sustained hypertensive patients, as recommended by the Japanese Society of Hypertension Guidelines for the Management of Hypertension; however, in other hypertensive patient types, the differences in SBP and DBP between office and home measurements differed by >5 mm Hg. Office and home BP measurements should be interpreted cautiously, keeping in mind the clinical setting.

  8. Difference between home and office blood pressures among treated hypertensive patients from the Japan Home versus Office Blood Pressure Measurement Evaluation (J-HOME) study.

    Science.gov (United States)

    Horikawa, Tsuyoshi; Obara, Taku; Ohkubo, Takayoshi; Asayama, Kei; Metoki, Hirohito; Inoue, Ryusuke; Kikuya, Masahiro; Hashimoto, Junichiro; Totsune, Kazuhito; Imai, Yutaka

    2008-06-01

    This study sought to clarify the factors associated with the magnitude of the difference between home and office blood pressures in treated hypertensive patients. Study subjects consisted of 3,308 essential hypertensive patients (mean age, 66 years; males, 44%) receiving antihypertensive treatment in primary care settings in Japan. Patients were classified into 3 groups (the home effect group, small difference group, and office effect group) according to tertiles of the magnitude of the office-home systolic blood pressure difference. Compared to the other two groups, the home effect group patients were significantly and independently older, were more often habitual drinkers, had a greater family history of cerebrovascular disease or personal history of ischemic heart disease, and were prescribed a greater number of antihypertensive drugs, non-amlodipine calcium channel blockers, and alpha-blockers as antihypertensive drugs. Compared to the other two groups, the office effect group patients were significantly and independently younger, included more females, less frequently had a family history of cerebrovascular disease or personal history of ischemic heart disease, and were less often prescribed alpha-blockers as antihypertensive drugs. The characteristics of home effect group patients and the factors negatively affecting the blood pressure difference were the same. Among treated hypertensive patients, compared to patients in the other groups, office effect group patients had a lower-risk profile, whereas home effect group patients had a higher-risk profile. These predictive factors might be useful clinically to help identify patients who may have a large difference between home and office blood pressures.

  9. Mapping Regional Differences of Local Pressure-Volume Curves With Electrical Impedance Tomography.

    Science.gov (United States)

    Beda, Alessandro; Carvalho, Alysson R; Carvalho, Nadja C; Hammermüller, Sören; Amato, Marcelo B P; Muders, Thomas; Gittel, Claudia; Noreikat, Katharina; Wrigge, Hermann; Reske, Andreas W

    2017-04-01

    Lung-protective mechanical ventilation aims to prevent alveolar collapse and overdistension, but reliable bedside methods to quantify them are lacking. We propose a quantitative descriptor of the shape of local pressure-volume curves derived from electrical impedance tomography, for computing maps that highlight the presence and location of regions of presumed tidal recruitment (i.e., elastance decrease during inflation, pressure-volume curve with upward curvature) or overdistension (i.e., elastance increase during inflation, downward curvature). Secondary analysis of experimental cohort study. University research facility. Twelve mechanically ventilated pigs. After induction of acute respiratory distress syndrome by hydrochloric acid instillation, animals underwent a decremental positive end-expiratory pressure titration (steps of 2 cm H2O starting from ≥ 26 cm H2O). Electrical impedance tomography-derived maps were computed at each positive end-expiratory pressure-titration step, and whole-lung CT taken every second steps. Airway flow and pressure were recorded to compute driving pressure and elastance. Significant correlations between electrical impedance tomography-derived maps and positive end-expiratory pressure indicate that, expectedly, tidal recruitment increases in dependent regions with decreasing positive end-expiratory pressure (p electrical impedance tomography-derived tidal recruitment with poorly aerated regions (r = 0.43; p electrical impedance tomography-derived overdistension with nonaerated regions at lower positive end-expiratory pressures and with hyperaerated regions at higher positive end-expiratory pressures (r ≥ 0.72; p electrical impedance tomography-derived maps showed nonnegligible regions of presumed overdistension and tidal recruitment. Electrical impedance tomography-derived maps of pressure-volume curve shapes allow to detect regions in which elastance changes during inflation. This could promote individualized mechanical

  10. Transport properties of the Callovo-Oxfordian clay rock under partially saturated conditions

    Science.gov (United States)

    Jougnot, D.; Revil, A.; Lu, N.; Wayllace, A.

    2010-08-01

    A series of experiments were performed to characterize the permeability, the specific storage, the capillary pressure, the streaming potential coupling coefficient, and the electrical conductivity of a very low permeability Callovo-Oxfordian clay rock at different water saturations. The Callovo-Oxfordian formation is presently investigated as a potential host to store nuclear wastes because of its very low permeability (typically 10 nd at saturation) and high specific surface area. We first present the constitutive transport equations including an electrokinetic cross-coupling term in the generalized Darcy and Ohm constitutive equations. Then we present new experimental results using measurements of transient weight losses of samples submitted to a change in the relative humidity imposed by an automated humidity system in a hermetic chamber. These experiments are interpreted with a 1-D analytical model of the coupled hydromechanical and transport equations. The hydromechanical transport properties (relative permeability and specific storage) of this clay rock are investigated in the relative saturation range from 0.23 to 0.70. We demonstrate that below 30% in relative humidity, the flux of the vapor phase with respect to the flux of the liquid water phase cannot be neglected. The relative apparent permeability can be described by a simple power law relationship with the saturation. In addition, we measure the electrical conductivity and the streaming potential coupling coefficient at various saturations. The electrical conductivity is described by a model accounting for electrical double-layer contributions to surface conductivity. The measurement of the streaming potential coupling coefficient agrees with a power law model for the coupling coefficient versus the relative water saturation. A relationship between the exponent used to characterize the relative permeability and the second Archie's exponent used to describe the dependence of the electrical conductivity

  11. Age-related, interindividual, and right/left differences in anterior-posterior foot pressure ratio in preschool children.

    Science.gov (United States)

    Matsuda, Shigeki; Demura, Shinichi

    2013-04-20

    This study aimed to examine age-related, interindividual, and right/left differences in anterior-posterior foot pressure ratio in 764 preschool children (364 boys and 400 girls) aged 3.5-6.5 years. Subjects maintained an upright standing posture for 10 seconds on the Footview Clinic, an instrument designed to calculate the anterior-posterior foot pressure ratio. The ratio of anterior foot pressure in each subject's right and left feet was selected as a variable, and the mean of a 10 s measurement was used for analysis. The ratio of anterior foot pressure was significantly larger in the right foot than in the left foot. With regard to age, the ratio of anterior foot pressure was significantly larger in children aged over 4.5 years than in children aged 3.5 years. It was also larger in children aged 6 and 6.5 years than in children aged 4 years. Interindividual differences in variables were large, and coefficients of variance were highest in children aged 3.5 years and lowest in children aged 6.5 years. In conclusion, anterior foot pressure increases with age in preschool children. Interindividual differences in anterior foot pressure are large and tend to decrease with age. Furthermore, the anterior foot pressure is slightly higher in the right foot than in the left foot. These results will be useful for various studies, such as examining relationships between the anterior-posterior foot pressure ratio and factors, such as untouched toes, physical fitness, and level of exercise.

  12. Postural control in a simulated saturation dive to 240 msw.

    OpenAIRE

    Goplen, Frederik Kragerud; Aasen, T. B.; Nordahl, Stein Helge G

    2007-01-01

    INTRODUCTION: There is evidence that increased ambient pressure causes an increase in postural sway. This article documents postural sway at pressures not previously studied and discusses possible mechanisms. METHODS: Eight subjects participated in a dry chamber dive to 240 msw (2.5 MPa) saturation pressure. Two subjects were excluded due to unilateral caloric weakness before the dive. Postural sway was measured on a force platform. The path length described by the center of pr...

  13. Prevention Practice Differences Among Persons With Spinal Cord Injuries Who Rarely Versus Frequently Sustain Pressure Ulcers

    Science.gov (United States)

    Jones, Michael L.; Marini, Irmo; Slate, John R.

    2005-01-01

    Pressure ulcers are common among people with spinal cord injury (SCI) and not only are costly to treat but also affect the quality of life of those affected by them. Despite a plethora of literature on prevention, there are few wellness studies focusing on the practices of people who do not develop pressure ulcers. This preliminary study sought to…

  14. Composition and crystallinity of silicon nanoparticles synthesised by hot wire thermal catalytic pyrolysis at different pressures

    CSIR Research Space (South Africa)

    Scriba, MR

    2009-04-01

    Full Text Available The effect of pressure on the structure and composition of silicon nanoparticles synthesized by hot wire thermal catalytic pyrolysis (HW-TCP) of pure silane has been investigated. Light brown powders were produced at silane pressures of 10 and 50...

  15. Pigmented and albino rats differ in their responses to moderate, acute and reversible intraocular pressure elevation.

    Science.gov (United States)

    Gurdita, Akshay; Tan, Bingyao; Joos, Karen M; Bizheva, Kostadinka; Choh, Vivian

    2017-06-01

    To compare the electrophysiological and morphological responses to acute, moderately elevated intraocular pressure (IOP) in Sprague-Dawley (SD), Long-Evans (LE) and Brown Norway (BN) rat eyes. Eleven-week-old SD (n = 5), LE (n = 5) and BN (n = 5) rats were used. Scotopic threshold responses (STRs), Maxwellian flash electroretinograms (ERGs) or ultrahigh-resolution optical coherence tomography (UHR-OCT) images of the rat retinas were collected from both eyes before, during and after IOP elevation of one eye. IOP was raised to ~35 mmHg for 1 h using a vascular loop, while the other eye served as a control. STRs, ERGs and UHR-OCT images were acquired on 3 days separated by 1 day of no experimental manipulation. There were no significant differences between species in baseline electroretinography. However, during IOP elevation, peak positive STR amplitudes in LE (mean ± standard deviation 259 ± 124 µV) and BN (228 ± 96 µV) rats were about fourfold higher than those in SD rats (56 ± 46 µV) rats (p = 0.0002 for both). Similarly, during elevated IOP, ERG b-wave amplitudes were twofold higher in LE and BN rats compared to those of SD rats (947 ± 129 µV and 892 ± 184 µV, vs 427 ± 138 µV; p = 0.0002 for both). UHR-OCT images showed backward bowing in all groups during IOP elevation, with a return to typical form about 30 min after IOP elevation. Differences in the loop-induced responses between the strains are likely due to different inherent retinal morphology and physiology.

  16. Bond durability of different resin cements to caries-affected dentin under simulated intrapulpal pressure.

    Science.gov (United States)

    Mohamed, M F; El Deeb, H A; Gomaa, I E; Mobarak, E H

    2015-01-01

    To evaluate the durability of the bond of different resin cement systems to normal dentin (ND) and caries-affected dentin (CAD) with and without simulated intrapulpal pressure (IPP). Molars with midcoronal caries were used. Occlusal enamel was cut to expose both dentin substrates (ND and CAD). Dentin substrates were differentiated using visual, tactile, caries-detecting dye, and dye-permeability methods. Prepared crown segments were equally divided according to the tested resin cement systems: etch-and-rinse resin cement, self-etch resin cement containing methacryloyloxydecyl dihydrogen phosphate (MDP), and self-adhesive resin cement. In addition to the dentin substrates and the resin cement types, the effect of application/storage conditions (with or without simulated IPP and with or without thermocycling) were tested. A microtensile bond strength test was done using a universal testing machine. Failure modes were determined using a scanning electron microscope. Etch-and-rinse resin cement strength values were significantly affected by the difference in the dentin substrates as well as the different application/storage conditions. Self-etch adhesive containing MDP bonded equally to ND and CAD and remained stable under all tested conditions. Self-adhesive resin cement revealed a similar bond to ND and CAD; however, its values were the lowest, especially when IPP and thermocycling were combined. Mixed failure was the predominant failure mode. Etch-and-rinse resin cement was sensitive to dentin substrate and application/storage conditions. Resin cement with self-etch adhesive containing MDP revealed more reliable bonding to ND/CAD even when IPP and thermocycling were combined. The bonding of the self-adhesive resin cement could not compete with other resin cements.

  17. Ethnic differences in the effect of environmental stressors on blood pressure and hypertension in the Netherlands.

    Science.gov (United States)

    Agyemang, Charles; van Hooijdonk, Carolien; Wendel-Vos, Wanda; Ujcic-Voortman, Joanne K; Lindeman, Ellen; Stronks, Karien; Droomers, Mariel

    2007-06-23

    Evidence strongly suggests that the neighbourhood in which people live influences their health. Despite this, investigations of ethnic differences in cardiovascular risk factors have focused mainly on individual-level characteristics. The main purpose of this study was to investigate associations between neighbourhood-level environmental stressors (crime, housing density, nuisance from alcohol and drug misuse, quality of green space and social participation), and blood pressure (BP) and hypertension among different ethnic groups. Individual data from the Amsterdam Health Survey 2004 were linked to data on neighbourhood stressors creating a multilevel design for data analysis. The study sample consisted of 517 Dutch, 404 Turkish and 365 Moroccans living in 15 neighbourhoods in Amsterdam, the Netherlands. Amongst Moroccans, high density housing and nuisance from drug misuse were associated with a higher systolic BP, while high quality of green space and social participation were associated with a lower systolic BP. High level of nuisance from drug misuse was associated with a higher diastolic BP. High quality of green space was associated with lower odds of hypertension. Amongst Turkish, high level of crime and nuisance from motor traffic were associated with a higher diastolic BP. Similar associations were observed among the Dutch group but none of the differences were statistically significant. The study findings show that neighbourhood-level stressors are associated with BP in ethnic minority groups but were less evident in the Dutch group. These findings might imply that the higher BP levels found in some ethnic minority groups might be partly due to their greater susceptibility to the adverse neighbourhood environment in which many ethnic minority people live. Primary prevention measures targeting these neighbourhood stressors may have an impact in reducing high BP related morbidity and mortality among ethnic minority groups.

  18. Ethnic differences in the effect of environmental stressors on blood pressure and hypertension in the Netherlands

    Directory of Open Access Journals (Sweden)

    Lindeman Ellen

    2007-06-01

    Full Text Available Abstract Background Evidence strongly suggests that the neighbourhood in which people live influences their health. Despite this, investigations of ethnic differences in cardiovascular risk factors have focused mainly on individual-level characteristics. The main purpose of this study was to investigate associations between neighbourhood-level environmental stressors (crime, housing density, nuisance from alcohol and drug misuse, quality of green space and social participation, and blood pressure (BP and hypertension among different ethnic groups. Methods Individual data from the Amsterdam Health Survey 2004 were linked to data on neighbourhood stressors creating a multilevel design for data analysis. The study sample consisted of 517 Dutch, 404 Turkish and 365 Moroccans living in 15 neighbourhoods in Amsterdam, the Netherlands. Results Amongst Moroccans, high density housing and nuisance from drug misuse were associated with a higher systolic BP, while high quality of green space and social participation were associated with a lower systolic BP. High level of nuisance from drug misuse was associated with a higher diastolic BP. High quality of green space was associated with lower odds of hypertension. Amongst Turkish, high level of crime and nuisance from motor traffic were associated with a higher diastolic BP. Similar associations were observed among the Dutch group but none of the differences were statistically significant. Conclusion The study findings show that neighbourhood-level stressors are associated with BP in ethnic minority groups but were less evident in the Dutch group. These findings might imply that the higher BP levels found in some ethnic minority groups might be partly due to their greater susceptibility to the adverse neighbourhood environment in which many ethnic minority people live. Primary prevention measures targeting these neighbourhood stressors may have an impact in reducing high BP related morbidity and mortality

  19. Different drug classes have variable effects on blood pressure depending on the time of day.

    Science.gov (United States)

    Morgan, Trefor O; Anderson, Adrianne

    2003-01-01

    Blood pressure (BP) is controlled by a variety of systems, the activities of which vary throughout the day. As drugs are developed that selectively block these systems, the fall in BP may not be consistent over 24 h. A total of 24 patients (aged >65 years) with systolic BP (SBP; >150 mm Hg) that had not been treated entered a substudy of a larger study performed in 74 patients. In a double blind, crossover study with a balanced design, they received placebo, atenolol 50 mg, perindopril 8 mg, felodipine 10 mg, or hydrochlorothiazide 50 mg. The study periods were 2 months. Ambulatory BP monitoring was performed at the end of each period, and was divided into awake periods (9:00 AM to 10:00 PM), sleep periods (12:00 AM to 6:00 AM), and morning periods (6:00 AM to 9:00 AM). Medication was taken at 9:00 AM. The four drug classes lowered 24-h mean SBP (P morning SBP, and the falls with the other three drugs were significant and were greater than the fall with atenolol. The fall in sleep BP with perindopril was greater than with the other drug classes. The awake-sleep difference in SBP increased with perindopril, stayed the same with felodipine and hydrochlorothiazide, and was reduced by atenolol. In this study, the response to the different drug classes differed. The response to drugs that work relatively nonspecifically (diuretics, calcium blockers) was relatively consistent over 24 h. The response to beta blockers and to angiotensin converting enzyme inhibitors reflected the activity of control systems. This finding supports the concept of multiple drug therapy that may need to be tailored to the time of day.

  20. Saturated fats: a perspective from lactation and milk composition.

    Science.gov (United States)

    German, J Bruce; Dillard, Cora J

    2010-10-01

    For recommendations of specific targets for the absolute amount of saturated fat intake, we need to know what dietary intake is most appropriate? Changing agricultural production and processing to lower the relative quantities of macronutrients requires years to accomplish. Changes can have unintended consequences on diets and the health of subsets of the population. Hence, what are the appropriate absolute amounts of saturated fat in our diets? Is the scientific evidence consistent with an optimal intake of zero? If not, is it also possible that a finite intake of saturated fats is beneficial to overall health, at least to a subset of the population? Conclusive evidence from prospective human trials is not available, hence other sources of information must be considered. One approach is to examine the evolution of lactation, and the composition of milks that developed through millennia of natural selective pressure and natural selection processes. Mammalian milks, including human milk, contain 50% of their total fatty acids as saturated fatty acids. The biochemical formation of a single double bond converting a saturated to a monounsaturated fatty acid is a pathway that exists in all eukaryotic organisms and is active within the mammary gland. In the face of selective pressure, mammary lipid synthesis in all mammals continues to release a significant content of saturated fatty acids into milk. Is it possible that evolution of the mammary gland reveals benefits to saturated fatty acids that current recommendations do not consider?

  1. Brine Distribution after Vacuum Saturation

    DEFF Research Database (Denmark)

    Hedegaard, Kathrine; Andersen, Bertel Lohmann

    1999-01-01

    Experiments with the vacuum saturation method for brine in plugs of chalk showed that a homogeneous distribution of brine cannot be ensured at saturations below 20% volume. Instead of a homogeneous volume distribution the brine becomes concentrated close to the surfaces of the plugs...

  2. Misconceptions in Reporting Oxygen Saturation

    NARCIS (Netherlands)

    Toffaletti, John; Zijlstra, Willem G.

    2007-01-01

    BACKGROUND: We describe some misconceptions that have become common practice in reporting blood gas and cooximetry results. In 1980, oxygen saturation was incorrectly redefined in a report of a new instrument for analysis of hemoglobin (Hb) derivatives. Oxygen saturation (sO(2)) was redefined as the

  3. Response of blood pressure to maximum exercise in hypertensive patients under different therapeutic programs

    Directory of Open Access Journals (Sweden)

    Carreira Maria Angela Magalhães de Queiroz

    2000-01-01

    Full Text Available OBJECTIVE: To evaluate the behavior of blood pressure during exercise in patients with hypertension controlled by frontline antihypertension drugs. METHODS: From 979ergometric tests we retrospectively selected 49 hipertensive patients (19 males. The age was 53±12 years old and normal range rest arterial pressure ( or = 10 mmHg/MET; or increase of diastolic pressure greater than 15 mmHg. RESULTS: Physiologic response of arterial blood pressure occurred in 50% of patients on beta blockers, the best one (p<0.05, in 36% and 31% on calcium antagonists and on diuretics, respectively, and in 20% on angiotensin converting enzyme inhibitor, the later the leastr one (p<0.05. CONCLUSION: Beta-blockers were more effective than calcium antagonists, diuretics and angiotensin-converting enzyme inhibitors in controlling blood pressure during exercise, and angiotensin converting enzyme inhibitors the least effective drugs.

  4. Soil Structure and Saturated Hydraulic Conductivity

    Science.gov (United States)

    Houskova, B.; Nagy, V.

    The role of soil structure on saturated hydraulic conductivity changes is studied in plough layers of texturally different soils. Three localities in western part of Slovakia in Zitny ostrov (Corn Island) were under investigation: locality Kalinkovo with light Calcaric Fluvisol (FAO 1970), Macov with medium heavy Calcari-mollic Fluvisol and Jurova with heavy Calcari-mollic Fluvisol. Soil structure was determined in dry as well as wet state and in size of macro and micro aggregates. Saturated hydraulic conductivity was measured by the help of double ring method. During the period of ring filling the soil surface was protected against aggregates damage by falling water drops. Spatial and temporal variability of studied parameters was evaluated. Cultivated crops were ensilage maize at medium heavy and heavy soil and colza at light soil. Textural composition of soil and actual water content at the beginning of measurement are one of major factor affecting aggregate stability and consequently also saturated hydraulic conductivity.

  5. Fullerene Transport in Saturated Porous Media

    Science.gov (United States)

    We investigated the effects of background solution chemistry and residence time within the soil column on the transport of aqu/C60 through saturated ultrapure quartz sand columns. Aqu/C60 breakthrough curves were obtained under different pore water velocities, solution pHs, and i...

  6. Activity classification based on inertial and barometric pressure sensors at different anatomical locations.

    Science.gov (United States)

    Moncada-Torres, A; Leuenberger, K; Gonzenbach, R; Luft, A; Gassert, R

    2014-07-01

    Miniature, wearable sensor modules are a promising technology to monitor activities of daily living (ADL) over extended periods of time. To assure both user compliance and meaningful results, the selection and placement site of sensors requires careful consideration. We investigated these aspects for the classification of 16 ADL in 6 healthy subjects under laboratory conditions using ReSense, our custom-made inertial measurement unit enhanced with a barometric pressure sensor used to capture activity-related altitude changes. Subjects wore a module on each wrist and ankle, and one on the trunk. Activities comprised whole body movements as well as gross and dextrous upper-limb activities. Wrist-module data outperformed the other locations for the three activity groups. Specifically, overall classification accuracy rates of almost 93% and more than 95% were achieved for the repeated holdout and user-specific validation methods, respectively, for all 16 activities. Including the altitude profile resulted in a considerable improvement of up to 20% in the classification accuracy for stair ascent and descent. The gyroscopes provided no useful information for activity classification under this scheme. The proposed sensor setting could allow for robust long-term activity monitoring with high compliance in different patient populations.

  7. Emergence and Stability of High-Pressure Resistance in Different Food-Borne Pathogens

    Science.gov (United States)

    Vanlint, Dietrich; Rutten, Nele; Michiels, Chris W.

    2012-01-01

    High hydrostatic pressure (HHP) processing is becoming a valuable nonthermal food pasteurization technique, although there is reasonable concern that bacterial HHP resistance could compromise the safety and stability of HHP-processed foods. While the degree of natural HHP resistance has already been shown to vary greatly among and within bacterial species, a still unresolved question remains as to what extent different food-borne pathogens can actually develop HHP resistance. In this study, we therefore examined and compared the intrinsic potentials for HHP resistance development among strains of Escherichia coli, Shigella flexneri, Salmonella enterica serovars Typhimurium and Enteritidis, Yersinia enterocolitica, Aeromonas hydrophila, Pseudomonas aeruginosa, and Listeria innocua using a selective enrichment approach. Interestingly, of all strains examined, the acquisition of extreme HHP resistance could be detected in only some of the E. coli strains, indicating that a specific genetic predisposition might be required for resistance development. Furthermore, once acquired, HHP resistance proved to be a very stable trait that was maintained for >80 generations in the absence of HHP exposure. Finally, at the mechanistic level, HHP resistance was not necessarily linked to derepression of the heat shock genes and was not related to the phenomenon of persistence. PMID:22344661

  8. Emergence and stability of high-pressure resistance in different food-borne pathogens.

    Science.gov (United States)

    Vanlint, Dietrich; Rutten, Nele; Michiels, Chris W; Aertsen, Abram

    2012-05-01

    High hydrostatic pressure (HHP) processing is becoming a valuable nonthermal food pasteurization technique, although there is reasonable concern that bacterial HHP resistance could compromise the safety and stability of HHP-processed foods. While the degree of natural HHP resistance has already been shown to vary greatly among and within bacterial species, a still unresolved question remains as to what extent different food-borne pathogens can actually develop HHP resistance. In this study, we therefore examined and compared the intrinsic potentials for HHP resistance development among strains of Escherichia coli, Shigella flexneri, Salmonella enterica serovars Typhimurium and Enteritidis, Yersinia enterocolitica, Aeromonas hydrophila, Pseudomonas aeruginosa, and Listeria innocua using a selective enrichment approach. Interestingly, of all strains examined, the acquisition of extreme HHP resistance could be detected in only some of the E. coli strains, indicating that a specific genetic predisposition might be required for resistance development. Furthermore, once acquired, HHP resistance proved to be a very stable trait that was maintained for >80 generations in the absence of HHP exposure. Finally, at the mechanistic level, HHP resistance was not necessarily linked to derepression of the heat shock genes and was not related to the phenomenon of persistence.

  9. Comparison of different intraocular pressure measurement techniques in normal eyes and post small incision lenticule extraction

    Directory of Open Access Journals (Sweden)

    Hosny M

    2017-07-01

    Full Text Available Mohamed Hosny, Fayrouz Aboalazayem, Hoda El Shiwy, Mohsen Salem Department of Ophthalmology, Cairo University, Giza, Egypt Purpose: The purpose of the study was to determine the accuracy of intraocular pressure (IOP measurement after small incision lenticule extraction (SMILE using Goldmann applanation tonometry (GAT and ocular response analyzer (ORA.Methods: This is a prospective clinical study that was conducted on 30 eyes in the interval between February 2016 and September 2016. The age of the patients ranged between 19 and 40 years. The patients underwent SMILE surgery using the femto laser. IOP was measured preoperatively and 1 month postoperatively by both techniques, the GAT and the ORA.Results: GAT recorded lower values than ORA values (IOPcc preoperatively and postoperatively and the difference was statistically significant. Both GAT and ORA IOP measurements decreased after SMILE. There was no statistically significant correlation between the changes in the GAT and ORA readings and the postoperative corneal pachymetry or the lenticule thickness. Both corneal hysteresis and corneal resistance factor showed significant decline after the procedure, which correlated with the lenticule thickness.Conclusion: SMILE causes significant reduction in IOP measurement by ORA and GAT. Corneal biomechanics decreases following SMILE and this correlates with lenticule thickness. Keywords: ocular response analyzer, small incision lenticule extraction, corneal hysteresis

  10. Ethnic differences in blood pressure from early pregnancy to postpartum: a Norwegian cohort study.

    Science.gov (United States)

    Waage, Christin W; Mdala, Ibrahimu; Jenum, Anne Karen; Michelsen, Trond M; Birkeland, Kåre I; Sletner, Line

    2016-06-01

    To examine blood pressure (BP) differences and changes between and within ethnic Western European, South Asian, Middle Eastern, East Asian, African, and East European living in Norway, from early pregnancy to postpartum and to explore associations between BP and explanatory variables. This was a population-based cohort study of 811 healthy pregnant women, 59% had ethnic minority origin. Participants were from Western Europe, Eastern Europe, South Asia, East Asia, Middle East, and Africa. We performed ANOVA, generalized estimating equations linear regression and multiple linear regression analysis. At 15 weeks' gestation, mean SBP were 4.9-7.0 mmHg lower and mean DBP 2.1-3.4 mmHg lower for the non-Europeans compared with Western Europeans. SBP increased in all non-European groups from 15 weeks' gestation to 14 weeks' postpartum (P age, family history of cardiovascular disease, prepregnancy BMI, and prepregnancy physical activity. Age, prepregnancy BMI, prepregnancy physical activity, postpartum weight retention, and breastfeeding were independently associated with postpartum BP (P Pregnancy may have a more adverse effect on BP trajectories from early pregnancy to postpartum among non-European women compared with Western Europeans, despite their more favorable BP in early pregnancy.

  11. Different effect of percutaneous plate insertion via anteromedial vs anterolateral approach on intracompartmental pressure of the leg: A cadaveric study.

    Science.gov (United States)

    Amarase, Chavarin; Thimasarn, Wanchat; Tantavisut, Saran; Huanmanop, Thanasil; Wangroongsub, Yongsak; Limthongkul, Worawat

    2017-11-01

    Currently Minimally Invasive Plate Osteosynthesis (MIPO) technique for tibial shaft fracture management has gained wide attention. However, an increased intracompartmental pressure after the plate insertion may result in postoperative acute compartment syndrome. We reported the difference of immediate effect of percutaneous plate insertion using 2 approaches of MIPO technique on anterior compartment pressure of the legs. Eight soft cadaveric legs (one female and three males) without previous history of skeletal trauma or surgery were infused with normal saline to create the sustained intracompartmental pressure of 20mm Hg in all four compartments. The Synthes(®) 4.5mm 11-hole Narrow Locking Compression Plate was inserted via anteromedial and anterolateral approach. Anterior compartment pressure was measured by portable digital monitoring device through side-port needle (Stryker(®) Intracompartmental Monitoring Device) before and after plate insertion for each approach. By using anteromedial approach, a mean of anterior compartment pressure was increased by 0.375mm Hg after plate insertion (5 of 8 legs had no change in pressure and the remaining 3 resulted in 1mm Hg pressure elevation). For anterolateral plate insertion, all of the 8 legs had an elevation of anterior compartment pressure with a mean of 3.5mmHg (ranged from 2 to 6mm Hg). When both approaches were compared to each other, the anterolateral plate insertion resulted in higher intracompartmental pressure elevation of the anterior compartment than the anteromedial approach. Surgeon should be more aware of acute compartment syndrome when considering the anterolateral approach in treating close tibial fracture. However, in patients with suspected acute compartment syndrome, close observation and continuous monitoring of the intracompartmental pressure is still imperative for all healthcare provider. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Sex Differences in Peripheral Augmentation Index and Arterial Reservoir Pressure during Upper Limb Postural Shifts

    Directory of Open Access Journals (Sweden)

    Kevin S. Heffernan

    2014-01-01

    Full Text Available We examined the peripheral hemodynamic response to passive arm postural changes in young men and women. Radial artery pulse waveforms were captured using applanation tonometry in 20 men (age 27 ± 2 yrs, BMI 25 ± 1 kg/m2 and 20 women (age 27 ± 2 yrs, BMI 23±1 kg/m2. Arm position was maintained at either heart level or supported 14 cm above/below heart level in a randomized fashion. Systolic augmentation index (sAIx and diastolic augmentation index (dAIx were used as estimates of pressure from wave reflections arriving in systole and diastole, respectively. A novel reservoir-wave separation technique was used to obtain arterial reservoir pressure (pressure generated by arterial capacitance. Women showed a significant reduction in radial diastolic pressure-time integral (DPTI (P0.05 or dAIx (P>0.05 when moving the arm from below to above heart level. Conversely, men showed an attenuated change in radial DPTI (P>0.05 concomitant with significant increases in reservoir pressure (P<0.05, sAIx (P<0.05, and dAIx (P<0.05. Gravity-mediated changes in regional hemodynamics produced by passive arm postural shifts are sex specific. Men demonstrate less change in regional diastolic pressure concomitant with increased augmentation index and arterial reservoir pressure.

  13. Emission features and expansion dynamics of nanosecond laser ablation plumes at different ambient pressures

    Science.gov (United States)

    Farid, N.; Harilal, S. S.; Ding, H.; Hassanein, A.

    2014-01-01

    The influence of ambient pressure on the spectral emission features and expansion dynamics of a plasma plume generated on a metal target has been investigated. The plasma plumes were generated by irradiating Cu targets using 6 ns, 1064 nm pulses from a Q-switched Nd:YAG laser. The emission and expansion dynamics of the plasma plumes were studied by varying air ambient pressure levels ranging from vacuum to atmospheric pressure. The ambient pressure levels were found to affect both the line intensities and broadening along with the signal to background and signal to noise ratios and the optimum pressure conditions for analytical applications were evaluated. The characteristic plume parameters were estimated using emission spectroscopy means and noticed that the excitation temperature peaked ˜300 Torr, while the electron density showed a maximum ˜100 Torr. Fast-gated images showed a complex interaction between the plume and background air leading to changes in the plume geometry with pressure as well as time. Surface morphology of irradiated surface showed that the pressure of the ambient gas affects the laser-target coupling significantly.

  14. Emission features and expansion dynamics of nanosecond laser ablation plumes at different ambient pressures

    Energy Technology Data Exchange (ETDEWEB)

    Farid, N. [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Key Laboratory of Materials Modification by Laser, Ion and electron Beams, School of Physics and Optical Engineering, Dalian University of Technology, Dalian (China); Harilal, S. S., E-mail: hari@purdue.edu; Hassanein, A. [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Ding, H. [Key Laboratory of Materials Modification by Laser, Ion and electron Beams, School of Physics and Optical Engineering, Dalian University of Technology, Dalian (China)

    2014-01-21

    The influence of ambient pressure on the spectral emission features and expansion dynamics of a plasma plume generated on a metal target has been investigated. The plasma plumes were generated by irradiating Cu targets using 6 ns, 1064 nm pulses from a Q-switched Nd:YAG laser. The emission and expansion dynamics of the plasma plumes were studied by varying air ambient pressure levels ranging from vacuum to atmospheric pressure. The ambient pressure levels were found to affect both the line intensities and broadening along with the signal to background and signal to noise ratios and the optimum pressure conditions for analytical applications were evaluated. The characteristic plume parameters were estimated using emission spectroscopy means and noticed that the excitation temperature peaked ∼300 Torr, while the electron density showed a maximum ∼100 Torr. Fast-gated images showed a complex interaction between the plume and background air leading to changes in the plume geometry with pressure as well as time. Surface morphology of irradiated surface showed that the pressure of the ambient gas affects the laser-target coupling significantly.

  15. Comparison of pulseoximetry oxygen saturation and arterial oxygen saturation in open heart intensive care unit

    Directory of Open Access Journals (Sweden)

    Alireza Mahoori

    2013-08-01

    Full Text Available Background: Pulseoximetry is widely used in the critical care setting, currently used to guide therapeutic interventions. Few studies have evaluated the accuracy of SPO2 (puls-eoximetry oxygen saturation in intensive care unit after cardiac surgery. Our objective was to compare pulseoximetry with arterial oxygen saturation (SaO2 during clinical routine in such patients, and to examine the effect of mild acidosis on this relationship.Methods: In an observational prospective study 80 patients were evaluated in intensive care unit after cardiac surgery. SPO2 was recorded and compared with SaO2 obtained by blood gas analysis. One or serial arterial blood gas analyses (ABGs were performed via a radial artery line while a reliable pulseoximeter signal was present. One hundred thirty seven samples were collected and for each blood gas analyses, SaO2 and SPO2 we recorded.Results: O2 saturation as a marker of peripheral perfusion was measured by Pulseoxim-etry (SPO2. The mean difference between arterial oxygen saturation and pulseoximetry oxygen saturation was 0.12%±1.6%. A total of 137 paired readings demonstrated good correlation (r=0.754; P<0.0001 between changes in SPO2 and those in SaO2 in samples with normal hemoglobin. Also in forty seven samples with mild acidosis, paired readings demonstrated good correlation (r=0.799; P<0.0001 and the mean difference between SaO2 and SPO2 was 0.05%±1.5%.Conclusion: Data showed that in patients with stable hemodynamic and good signal quality, changes in pulseoximetry oxygen saturation reliably predict equivalent changes in arterial oxygen saturation. Mild acidosis doesn’t alter the relation between SPO2 and SaO2 to any clinically important extent. In conclusion, the pulse oximeter is useful to monitor oxygen saturation in patients with stable hemodynamic.

  16. A comparative analysis of young tennis player target accuracy when using balls inflated under different pressures

    Directory of Open Access Journals (Sweden)

    Dmytro Krylov

    2017-06-01

    Full Text Available Purpose: make a comparative analysis of the target accuracy of ten-year tennis players in performing test exercises with balls with a pressure of 75% of the standard and balls with standard pressure. Material & Methods: in the study participated 8 tennis players of ten years of age, the group 5 years of training. In the course of the research, the following methods were used: analysis and generalization of literature sources, analysis of documentary materials, testing, method of expert evaluations. Results: replacing balls with a pressure of 75% of the standard for standard leads to a deterioration in the target accuracy of ten-year tennis players, which is a consequence of distortion of the technical characteristics of movements. Conclusion: results of the study indicate the need for correction of the technique of players of this age in the transition from balls with a pressure of 75% from the standard to standard.

  17. Ideal resuscitation pressure for uncontrolled hemorrhagic shock in different ages and sexes of rats

    National Research Council Canada - National Science Library

    Li, Tao; Zhu, Yu; Tian, Kunlun; Xue, Mingying; Peng, Xiaoyong; Lan, Dan; Liu, Liangming

    2013-01-01

    Our previous studies demonstrated that 50-60 mmHg mean arterial blood pressure was the ideal target hypotension for uncontrolled hemorrhagic shock during the active hemorrhage in sexually mature rats...

  18. Effects of pressure and temperature on thermal contact resistance between different materials

    Directory of Open Access Journals (Sweden)

    Zhao Zhe

    2015-01-01

    Full Text Available To explore whether pressure and temperature can affect thermal contact resistance, we have proposed a new experimental approach for measurement of the thermal contact resistance. Taking the thermal contact resistance between phenolic resin and carbon-carbon composites, cuprum, and aluminum as the examples, the influence of the thermal contact resistance between specimens under pressure is tested by experiment. Two groups of experiments are performed and then an analysis on influencing factors of the thermal contact resistance is presented in this paper. The experimental results reveal that the thermal contact resistance depends not only on the thermal conductivity coefficient of materials, but on the interfacial temperature and pressure. Furthermore, the thermal contact resistance between cuprum and aluminum is more sensitive to pressure and temperature than that between phenolic resin and carbon-carbon composites.

  19. Simultaneous laser induced breakdown spectroscopy and Pd-assisted methane decomposition at different pressures

    Energy Technology Data Exchange (ETDEWEB)

    Reyhani, A. [Phys. Dept., Faculty of Science, Imam Khomeini International University, Qazvin, 34149-16818 (Iran, Islamic Republic of); Mortazavi, S.Z. [Phys. Dept., Amirkabir University of Technology, P.O. Box 15875-4413, Tehran (Iran, Islamic Republic of); Parvin, P., E-mail: parvin@aut.ac.ir [Phys. Dept., Amirkabir University of Technology, P.O. Box 15875-4413, Tehran (Iran, Islamic Republic of); Mahmoudi, Z. [Phys. Dept., Amirkabir University of Technology, P.O. Box 15875-4413, Tehran (Iran, Islamic Republic of)

    2012-08-15

    Methane decomposition is investigated during Pd-assisted laser induced plasma in the controlled chamber at various pressures using Q-switched Nd:YAG laser. Real time LIBS monitoring is applied to reveal the involved mechanisms during methane decomposition by inspecting the plasma parameters at mano-metric pressures of 1 to 10 mbar. The dependence of electron density and plasma temperature with pressure is also studied. It is shown that the plasma recreates higher hydrocarbons during the decomposition of methane. In addition, Fourier transform infrared spectroscopy, gas chromatography, scanning electron microscopy and transmission electron microscopy are applied to support the findings. - Highlights: Black-Right-Pointing-Pointer Simultaneous laser induced breakdown spectroscopy Black-Right-Pointing-Pointer Pd-assisted methane decomposition Black-Right-Pointing-Pointer Nanosecond pulsed laser decomposition of methane Black-Right-Pointing-Pointer Generation of higher hydrocarbon Black-Right-Pointing-Pointer Dependence of electron density and temperature of induced plasma with pressure.

  20. Saturation current spikes eliminated in saturable core transformers

    Science.gov (United States)

    Schwarz, F. C.

    1971-01-01

    Unsaturating composite magnetic core transformer, consisting of two separate parallel cores designed so impending core saturation causes signal generation, terminates high current spike in converter primary circuit. Simplified waveform, demonstrates transformer effectiveness in eliminating current spikes.

  1. Evidence for Skill Level Differences in the Thought Processes of Golfers During High and Low Pressure Situations

    Science.gov (United States)

    Whitehead, Amy E.; Taylor, Jamie A.; Polman, Remco C. J.

    2016-01-01

    Two studies examined differences in the cognition of golfers with differing levels of expertise in high and low pressure situations. In study 1, six high skill and six low skill golfers performed six holes of golf, while verbalizing their thoughts using Think Aloud (TA) protocol. Higher skilled golfers’ cognitive processes centered more on planning in comparison to lower skilled golfers. Study 2 investigated whether thought processes of golfers changed in response to competitive pressure. Eight high skill and eight moderate skilled golfers, completed a practice round and a competition round whilst verbalizing thoughts using TA. To create pressure in the competition condition, participants were instructed that monetary prizes would be awarded to the top three performers and scores of all golfers would be published in a league table in the club house. When performing under competitive pressure, it was found that higher skilled golfers were more likely to verbalize technical rules compared to practice conditions, especially during putting performance. This shift in cognition toward more technical aspects of motor performance was strongly related to scores on the Decision Specific Reinvestment Scale, suggesting individuals with a higher propensity for reinvestment show the largest changes in cognition under pressure. From a practical perspective, TA can aid a player, coach or sport psychologist by allowing thought processes to be identified and investigate a performer’s thoughts when faced with the pressure of a competition. PMID:26779085

  2. Evidence for skill level differences in the thought processes of golfers during high and low pressure situations.

    Directory of Open Access Journals (Sweden)

    Amy Elizabeth Whitehead

    2016-01-01

    Full Text Available Two studies examined differences in the cognition of golfers with differing levels of expertise in high and low pressure situations. In study 1, six high skill and six low skill golfers performed six holes of golf, while verbalizing their thoughts using Think Aloud (TA protocol. Higher skilled golfers’ cognitive processes centered more on planning in comparison to lower skilled golfers. Study 2 investigated whether thought processes of golfers changed in response to competitive pressure. Eight high skill and eight moderate skilled golfers, completed a practice round and a competition round whilst verbalizing thoughts using TA. To create pressure in the competition condition, participants were instructed that monetary prizes would be awarded to the top three performers and scores of all golfers would be published in a league table in the club house. When performing under competitive pressure, it was found that higher skilled golfers were more likely to verbalize technical rules compared to practice conditions, especially during putting performance. This shift in cognition toward more technical aspects of motor performance was strongly related to scores on the Decision Specific Reinvestment Scale, suggesting individuals with a higher propensity for reinvestment show the largest changes in cognition under pressure. From a practical perspective, TA can aid a player, coach or sport psychologist by allowing thought processes to be identified and investigate a performer’s thoughts when faced with the pressure of a competition.

  3. SHAD-Nisat: A Composite Study of Shallow Saturation Diving Incorporating Long Duration Air Saturation with Excursions, Deep Nitrox Saturation, and Switch from Nitrogen to Helium

    Science.gov (United States)

    1982-08-01

    exposures caused red blood cell losses; recovery began a few days after return to normal pressure. The divers were also deconditioned , presumably...5. Deconditioning following long saturation 1-15 6. Pulmonary function changes 1-15 7. Sickness in 7 atm nitrox 1-16 8. Performance and...II-l 1. Chamber system II-l a. Physical characteristics II-l b. Air supply system II-4 c. Pure gas supply II-4 d. Pressurization and

  4. Thermal and structural alternations in CuAlMnNi shape memory alloy by the effect of different pressure applications

    Science.gov (United States)

    Canbay, Canan Aksu; Polat, Tercan

    2017-09-01

    In this work the effects of the applied pressure on the characteristic transformation temperatures, the high temperature order-disorder phase transitions, the variation in diffraction peaks and the surface morphology of the CuAlMnNi shape memory alloy was investigated. The evolution of the transformation temperatures was studied by differential scanning calorimetry (DSC) with different heating and cooling rates. The differential thermal analysis measurements were performed to obtain the ordered-disordered phase transformations from room temperature to 900 °C. The characteristic transformation temperatures and the thermodynamic parameters were highly sensitive to variations in the applied pressure and also the applied pressure affected the thermodynamic parameters. The activation energy of the sample according to applied pressure values calculated by Kissinger method. The structural changes of the samples were studied by X-ray diffraction (XRD) measurements and by optical microscope observations at room temperature.

  5. Panethnic Differences in Blood Pressure in Europe: A Systematic Review and Meta-Analysis.

    Directory of Open Access Journals (Sweden)

    Pietro Amedeo Modesti

    Full Text Available People of Sub Saharan Africa (SSA and South Asians(SA ethnic minorities living in Europe have higher risk of stroke than native Europeans(EU. Study objective is to provide an assessment of gender specific absolute differences in office systolic(SBP and diastolic(DBP blood pressure(BP levels between SSA, SA, and EU.We performed a systematic review and meta-analysis of observational studies conducted in Europe that examined BP in non-selected adult SSA, SA and EU subjects. Medline, PubMed, Embase, Web of Science, and Scopus were searched from their inception through January 31st 2015, for relevant articles. Outcome measures were mean SBP and DBP differences between minorities and EU, using a random effects model and tested for heterogeneity. Twenty-one studies involving 9,070 SSA, 18,421 SA, and 130,380 EU were included. Compared with EU, SSA had higher values of both SBP (3.38 mmHg, 95% CI 1.28 to 5.48 mmHg; and 6.00 mmHg, 95% CI 2.22 to 9.78 in men and women respectively and DBP (3.29 mmHg, 95% CI 1.80 to 4.78; 5.35 mmHg, 95% CI 3.04 to 7.66. SA had lower SBP than EU(-4.57 mmHg, 95% CI -6.20 to -2.93; -2.97 mmHg, 95% CI -5.45 to -0.49 but similar DBP values. Meta-analysis by subgroup showed that SA originating from countries where Islam is the main religion had lower SBP and DBP values than EU. In multivariate meta-regression analyses, SBP difference between minorities and EU populations, was influenced by panethnicity and diabetes prevalence.1 The higher BP in SSA is maintained over decades, suggesting limited efficacy of prevention strategies in such group in Europe;2 The lower BP in Muslim populations suggests that yet untapped lifestyle and behavioral habits may reveal advantages towards the development of hypertension;3 The additive effect of diabetes, emphasizes the need of new strategies for the control of hypertension in groups at high prevalence of diabetes.

  6. Reproducibility of ambulatory blood pressure changes from the initial values on two different days

    Science.gov (United States)

    Ash, Garrett I.; Walker, Timothy J.; Olson, Kayla M.; Stratton, Jeffrey H.; Gómez, Ana L.; Kraemer, William J.; Volek, Jeff S.; Pescatello, Linda S.

    2013-01-01

    OBJECTIVE: We tested the reproducibility of changes in the ambulatory blood pressure (BP) from the initial values, an indicator of BP reactivity and cardiovascular health outcomes, in young, healthy adults. METHOD: The subjects wore an ambulatory BP monitor attached by the same investigator at the same time of day until the next morning on two different days (day 1 and day 2) separated by a week. We compared the ambulatory BP change from the initial values at hourly intervals over 24 waking and sleeping hours on days 1 and 2 using linear regression and repeated measures analysis of covariance. RESULTS: The subjects comprised 88 men and 57 women (mean age±SE 22.4±0.3 years) with normal BP (118.3±0.9/69.7±0.6 mmHg). For the total sample, the correlation between the ambulatory BP change on day 1 vs. day 2 over 24, waking, and sleeping hours ranged from 0.37–0.61; among women, the correlation was 0.38–0.71, and among men, it was 0.24–0.52. Among women, the ambulatory systolic/diastolic BP change was greater by 3.1±1.0/2.4±0.8 mmHg over 24 hours and by 3.0±1.1/2.4±0.8 mmHg over waking hours on day 1 than on day 2. The diastolic ambulatory BP change during sleeping hours was greater by 2.2±0.9 mmHg on day 1 than on day 2, but the systolic ambulatory BP change during sleeping hours on days 1 and 2 did not differ. Among men, the ambulatory BP change on days 1 and 2 did not differ. CONCLUSION: Our primary findings were that the ambulatory BP change from the initial values was moderately reproducible; however, it was more reproducible in men than in women. These results suggest that women, but not men, may experience an alerting reaction to initially wearing the ambulatory BP monitor. PMID:24473508

  7. WAter Saturation Shift Referencing (WASSR) for chemical exchange saturation transfer experiments

    Science.gov (United States)

    Kim, Mina; Gillen, Joseph; Landman, Bennett. A.; Zhou, Jinyuan; van Zijl, Peter C.M.

    2010-01-01

    Chemical exchange saturation transfer (CEST) is a contrast mechanism exploiting exchange-based magnetization transfer (MT) between solute and water protons. CEST effects compete with direct water saturation and conventional MT processes and generally can only be quantified through an asymmetry analysis of the water saturation spectrum (Z-spectrum) with respect to the water frequency, a process that is exquisitely sensitive to magnetic field inhomogeneities. Here, it is shown that direct water saturation imaging allows measurement of the absolute water frequency in each voxel, allowing proper centering of Z-spectra on a voxel-by-voxel basis independent of spatial B0 field variations. Optimal acquisition parameters for this “water saturation shift referencing” or “WASSR” approach were estimated using Monte Carlo simulations and later confirmed experimentally. The optimal ratio of the WASSR sweep width to the linewidth of the direct saturation curve was found to be 3.3–4.0, requiring a sampling of 16–32 points. The frequency error was smaller than 1 Hz at signal to noise ratios of 40 or higher. The WASSR method was applied to study glycogen, where the chemical shift difference between the hydroxyl (OH) protons and bulk water protons at 3T is so small (0.75–1.25 ppm) that the CEST spectrum is inconclusive without proper referencing. PMID:19358232

  8. Water saturation shift referencing (WASSR) for chemical exchange saturation transfer (CEST) experiments.

    Science.gov (United States)

    Kim, Mina; Gillen, Joseph; Landman, Bennett A; Zhou, Jinyuan; van Zijl, Peter C M

    2009-06-01

    Chemical exchange saturation transfer (CEST) is a contrast mechanism that exploits exchange-based magnetization transfer (MT) between solute and water protons. CEST effects compete with direct water saturation and conventional MT processes, and generally can only be quantified through an asymmetry analysis of the water saturation spectrum (Z-spectrum) with respect to the water frequency, a process that is exquisitely sensitive to magnetic field inhomogeneities. Here it is shown that direct water saturation imaging allows measurement of the absolute water frequency in each voxel, allowing proper centering of Z-spectra on a voxel-by-voxel basis independently of spatial B(0) field variations. Optimal acquisition parameters for this "water saturation shift referencing" (WASSR) approach were estimated using Monte Carlo simulations and later confirmed experimentally. The optimal ratio of the WASSR sweep width to the linewidth of the direct saturation curve was found to be 3.3-4.0, requiring a sampling of 16-32 points. The frequency error was smaller than 1 Hz at signal-to-noise ratios of 40 or higher. The WASSR method was applied to study glycogen, where the chemical shift difference between the hydroxyl (OH) protons and bulk water protons at 3T is so small (0.75-1.25 ppm) that the CEST spectrum is inconclusive without proper referencing.

  9. Differing predictive relationships between baseline LDL-C, systolic blood pressure, and cardiovascular outcomes.

    Science.gov (United States)

    Deedwania, Prakash C; Pedersen, Terje R; DeMicco, David A; Breazna, Andrei; Betteridge, D John; Hitman, Graham A; Durrington, Paul; Neil, Andrew

    2016-11-01

    Traditional cardiovascular risk factors, such as hypertension and dyslipidemia, predispose individuals to cardiovascular disease, particularly patients with diabetes. We investigated the predictive value of baseline systolic blood pressure (SBP) and low-density lipoprotein cholesterol (LDL-C) on the risk of vascular outcomes in a large population of patients at high risk of future cardiovascular events. Data were pooled from the TNT (Treating to New Targets), CARDS (Collaborative Atorvastatin Diabetes Study), and IDEAL (Incremental Decrease in End-Points Through Aggressive Lipid Lowering) trials and included a total of 21,727 patients (TNT: 10,001; CARDS: 2838; IDEAL: 8888). The effect of baseline SBP and LDL-C on cardiovascular events, coronary events, and stroke was evaluated using a multivariate Cox proportional-hazards model. Overall, risk of cardiovascular events was significantly higher for patients with higher baseline SBP or LDL-C. Higher baseline SBP was significantly predictive of stroke but not coronary events. Conversely, higher baseline LDL-C was significantly predictive of coronary events but not stroke. Results from the subgroup with diabetes (5408 patients; TNT: 1501; CARDS: 2838; IDEAL: 1069) were broadly consistent with those of the total cohort: baseline SBP and LDL-C were significantly predictive of cardiovascular events overall, with the association to LDL-C predominantly related to an effect on coronary events. However, baseline SBP was not predictive of either coronary or stroke events in the pooled diabetic population. In this cohort of high-risk patients, baseline SBP and LDL-C were significantly predictive of cardiovascular outcomes, but this effect may differ between the cerebrovascular and coronary systems. NCT00327691 (TNT); NCT00327418 (CARDS); NCT00159835 (IDEAL). Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  10. Intraocular pressure and photorefractive keratectomy: a comparison of three different tonometers.

    Science.gov (United States)

    Garzozi, H J; Chung, H S; Lang, Y; Kagemann, L; Harris, A

    2001-01-01

    To evaluate the intraocular pressure (IOP) with three different instruments, Goldmann applanation tonometer (GAT), noncontact tonometer, and Tono-Pen after photorefractive keratectomy (PRK) for myopia. A prospective case series study to evaluate preoperative and postoperative IOP measurements of 149 eyes at 12 months. We performed GAT, noncontact tonometry, Tono-Pen central, and Tono-Pen temporal periphery measurements. We also performed measurements of the central corneal thickness (CCT) by ultrasonic pachymetry and keratometry. Pre-operative IOP reading served as control for all studies. After PRK, IOP reading was significantly reduced in the treated eyes when compared with the control measurements (11.87+/-1.73 vs. 13.37+/-1.52 mm Hg, pPen central; 13.48+/-1.65 vs. 13.71+/-1.56 Hg, pPen temporal periphery). There was also a significant correlation between IOP reading changes measured by GAT, noncontact tonometer, Tono-Pen central, and change of CCT and between reduction of IOP reading and keratometry (r2>0.39, pIOP reading change by Tono-Pen temporal periphery and CCT was also significant but r2 value was only 0.034. Tono-Pen temporal periphery postoperative IOP measurements had the best correlation with preoperative GAT IOP (r2 = 0.57, pIOP reading as measured by GAT, noncontact tonometer, and Tono-Pen central; less so when measured by Tono-Pen temporal periphery. Early detection of glaucoma and IOP follow-up in glaucoma patients may be done best by peripheral Tono-Pen measurements over the nonablated cornea.

  11. The effect of different types of abdominal binders on intra-abdominal pressure

    Directory of Open Access Journals (Sweden)

    Hua-Yu Zhang

    2016-01-01

    Full Text Available Objectives: To investigate the effect of non-elastic/elastic abdominal binders on intra-vesical pressure (IVP, physiological functions, and clinical outcomes in laparotomy patients at the perioperative stage. Methods: This prospective study was conducted from May to October 2014 at the Trauma Surgery Department, Daping Hospital, Chongqing, China. Laparotomy patients were randomly divided into non-elastic abdominal binder group (28 patients, and elastic abdominal binder group (29 patients. Binders were applied for 14 days following the operation, or until discharge. Demographic information, Sequential Organ Failure Assessment (SOFA and Acute Physiology and Chronic Health Evaluation II (APACHE-II scores (prior to the operation, on the first day after operation, the day IVP measurement was stopped, and one day before discharge, and outcomes were recorded. The IVP was measured before the operation to postoperative day 7. Results: There were no significant differences in the demographic information, outcomes, SOFA or APACHE-II scores between the 2 groups. Initial out-of-bed mobilization occurred earlier in the elastic binder group (3.2 ± 2.0 versus 5.0 ± 3.7 days, p=0.028. A greater increase in IVP was observed in the non-elastic binder group than in the elastic binder group (2.9 ± 1.1 versus 1.1 ± 0.7 mm Hg, p=0.000. Conclusion: Elastic binders have relatively little effect on IVP and are more helpful at promoting postoperative recovery than non-elastic binders. Therefore, elastic binders are more suitable for clinical use.

  12. Optimal oxygen saturation in premature infants

    Directory of Open Access Journals (Sweden)

    Meayoung Chang

    2011-09-01

    Full Text Available There is a delicate balance between too little and too much supplemental oxygen exposure in premature infants. Since underuse and overuse of supplemental oxygen can harm premature infants, oxygen saturation levels must be monitored and kept at less than 95% to prevent reactive oxygen species-related diseases, such as retinopathy of prematurity and bronchopulmonary dysplasia. At the same time, desaturation below 80 to 85% must be avoided to prevent adverse consequences, such as cerebral palsy. It is still unclear what range of oxygen saturation is appropriate for premature infants; however, until the results of further studies are available, a reasonable target for pulse oxygen saturation (SpO2 is 90 to 93% with an intermittent review of the correlation between SpO2 and the partial pressure of arterial oxygen tension (PaO2. Because optimal oxygenation depends on individuals at the bedside making ongoing adjustments, each unit must define an optimal target range and set alarm limits according to their own equipment or conditions. All staff must be aware of these values and adjust the concentration of supplemental oxygen frequently.

  13. Experimental and numerical approaches of the hydro-mechanical behaviour of a quasi-saturated compacted clayey soil

    Directory of Open Access Journals (Sweden)

    Li Zhong-Sen

    2016-01-01

    Full Text Available The present research is funded by the French National Project « TerreDurable », which is dedicated to the study of soils in quasi-saturated conditions (close to saturation for the analysis of stability and settlement of earth structures such as embankment, dams. A global presentation of the drying-wetting test shows the volume change, air entry and soil-water characteristics of the soil at slurry and oven-dried conditions. Unsaturated undrained triaxial test was carried out in order to investigate the variation of pore-water pressure from quasi-saturated domain to saturation. The experimental results of the triaxial test are then modeled using a two-dimensional explicit finite difference program (Flac 2D. A constitutive law developed in the TerreDurable project allows better understanding the behaviour of quasi-saturated soils using the water retention curve of quasi-saturated domain proposed by Boutonnier (2007, 2010. A simple effective stress model is used (Cam Clay by taking into account both the suction and the compressibility of equivalent fluid (water + air. The results from numerical calculation and experimental measurements are compared.

  14. Differences in Blood Pressure Measurements Obtained Using an Automatic Oscillometric Sphygmomanometer Depending on Clothes-Wearing Status

    Science.gov (United States)

    Ki, Ji Hoon; Lee, Soo Hee

    2013-01-01

    Background According to the current guidelines for blood pressure monitoring, clinicians are recommended to measure blood pressure by completely exposing the upper arm. However, it is a common practice that blood pressure is measured with the cuff placed over the sleeve or with the sleeve rolled up. We therefore conducted this study to examine whether there are any differences in blood pressure measurements among the three different settings: the sleeve group, the rolled sleeve group, and the bare arm group. Methods We conducted the current study in 141 male and female adult patients who visited our clinical department. In these patients, we took repeatedly blood pressure measurements using the same automatic oscillometric device on three different settings. Then, we analyzed the results with the use of randomized block design analysis of variance. Results The mean values of systolic blood pressure (SBP) between the first reading and those of the second reading were 128.5 ± 10.6 mm Hg in the sleeve group, 128.3 ± 10.8 mm Hg in the rolled sleeve group, and 128.3 ± 10.7 mm Hg in the bare arm group. These results indicate that there were no significant differences among the three groups (P = 0.32). In addition, the mean values of diastolic blood pressure (DBP) between the first reading and those of the second reading were 80.7 ± 6.1 mm Hg in the sleeve group, 80.7 ± 6.1 mm Hg in the rolled sleeve group, and 80.6 ± 5.9 mm Hg in the bare arm group. These results indicate that there were no significant differences among the three groups (P = 0.77). In addition, based on the age, sex, past or current history of hypertension or diabetes mellitus, the thickness of sleeve, weight, a drinking history, and a smoking history, there were no significant differences in SBP and DBP among the three groups. Conclusion There were no significant differences in blood pressure measurements between the three different settings (the sleeve group, the rolled sleeve group, and the bare

  15. Mechanical behavior of saturated, consolidated, alumina powder compacts

    Science.gov (United States)

    Franks, George Vincent, Jr.

    Alumina slurries were prepared with three differing particle pair potentials produced by adjusting pH and salt concentration. The three pair potentials investigated were repulsive, strongly attractive and weakly attractive. Bodies were consolidated by pressure filtration, at applied pressures between 0.25 MPa and 150 MPa. The mechanical properties of these bodies were investigated by uniaxial compressive loading. High consolidation pressures lead to high forces at particle contacts which can push the particles together to form a strong touching network even when the particles are separated by a potential barrier in the slurry state. When particles are pushed into adhesive contact, the saturated, consolidated powder compacts are brittle. When a short ranged repulsive interparticle potential persists after consolidation, the specimens are plastic. Saturated bodies formed from strongly attractive slurries (flocculated at the isoelectric point pH 9) were plastic at low relative densities but were brittle at higher relative densities. Bodies formed from the repulsive slurries (dispersed at pH 4) were always brittle. Bodies consolidated from weakly attractive slurries (coagulated at pH 4, 5, 6, or 12 with additions of salt) were plastic at low consolidation pressures but became brittle at high consolidation pressures. This plastic-to-brittle transition depends on the shape of the pair potential, the size and morphology of the powder. The plastic specimens had stress-strain behavior characterized by a peak stress, followed by a lower flow stress. The peak stress reduced to the flow stress upon several reloading cycles. The effect of the slope of the repulsive potential barrier on the plastic-to-brittle transition was investigated. Alumina slurries coagulated at pH 12 with 0.5 M of Lisp+, Cssp+ and tetraethylammoniumsp+ chlorides were consolidated by pressure filtration. Consolidation pressures required to push particles together were greater for smaller counterions. The

  16. Laboratory calibration of the seismo-acoustic response of CO2 saturated sandstones

    Science.gov (United States)

    Siggins, A. F.; Lwin, M.; Wisman, P.

    2009-04-01

    % with liquid CO2 saturation. Similarly, flooding the dry core samples with brine increased the P-wave velocity-effective pressure response by approximately 3% but lowered the S-wave velocity response by 5%. Attenuations increased with liquid-phase CO2 flooding compared to the air-saturated case. Surprisingly, experimental data agreed well with the Gassmann fluid substitution calculations within experimental error for all saturants at higher effective pressures despite the theory being strictly only applicable to low-frequencies. The value of effective pressure, when this agreement occurred, varied with sandstone type. Discrepancies are thought to be due to differing micro crack populations equivalent to "soft porosity" in the microstructure of each sandstone type. The effective pressure at which the experimental data agreed with Gassmann occurred around 30 MPa. This is close to the effective pressure which will be present when injection is complete. Agreement with the Gassmann model at effective pressures is significant and gives some confidence in predicting seismic behaviour under similar field conditions from laboratory data when CO2 is injected.

  17. Differences in selective pressure on dhps and dhfr drug resistant mutations in western Kenya.

    Science.gov (United States)

    McCollum, Andrea M; Schneider, Kristan A; Griffing, Sean M; Zhou, Zhiyong; Kariuki, Simon; Ter-Kuile, Feiko; Shi, Ya Ping; Slutsker, Laurence; Lal, Altaf A; Udhayakumar, Venkatachalam; Escalante, Ananias A

    2012-03-22

    Understanding the origin and spread of mutations associated with drug resistance, especially in the context of combination therapy, will help guide strategies to halt and prevent the emergence of resistance. Unfortunately, studies have assessed these complex processes when resistance is already highly prevalent. Even further, information on the evolutionary dynamics leading to multidrug-resistant parasites is scattered and limited to areas with low or seasonal malaria transmission. This study describes the dynamics of strong selection for mutations conferring resistance against sulphadoxine-pyrimethamine (SP), a combination therapy, in western Kenya between 1992 and 1999, just before SP became first-line therapy (1999). Importantly, the study is based on longitudinal data, which allows for a comprehensive analysis that contrasts with previous cross-sectional studies carried out in other endemic regions. This study used 236 blood samples collected between 1992 and 1999 in the Asembo Bay area of Kenya. Pyrosequencing was used to determine the alleles of dihydrofolate reductase (dhfr) and dihydropterote synthase (dhps) genes. Microsatellite alleles spanning 138 kb around dhfr and dhps, as well as, neutral markers spanning approximately 100 kb on chromosomes 2 and 3 were characterized. By 1992, the South-Asian dhfr triple mutant was already spreading, albeit in low frequency, in this holoendemic Kenyan population, prior to the use of SP as a first-line therapy. Additionally, dhfr triple mutant alleles that originated independently from the predominant Southeast Asian lineage were present in the sample set. Likewise, dhps double mutants were already present as early as 1992. There is evidence for soft selective sweeps of two dhfr mutant alleles and the possible emergence of a selective sweep of double mutant dhps alleles between 1992 and 1997. The longitudinal structure of the dataset allowed estimation of selection pressures on various dhfr and dhps mutants relative to

  18. Administration-time differences in effects of hypertension medications on ambulatory blood pressure regulation.

    Science.gov (United States)

    Hermida, Ramón C; Ayala, Diana E; Fernández, José R; Mojón, Artemio; Smolensky, Michael H; Fabbian, Fabio; Portaluppi, Francesco

    2013-03-01

    Specific features of the 24-h blood pressure (BP) pattern are linked to progressive injury of target tissues and risk of cardiovascular disease (CVD) events. Several studies have consistently shown an association between blunted asleep BP decline and risk of fatal and nonfatal CVD events. Thus, there is growing focus on ways to properly control BP during nighttime sleep as well as during daytime activity. One strategy, termed chronotherapy, entails the timing of hypertension medications to endogenous circadian rhythm determinants of the 24-h BP pattern. Significant and clinically meaningful treatment-time differences in the beneficial and/or adverse effects of at least six different classes of hypertension medications, and their combinations, are now known. Generally, calcium channel blockers (CCBs) are more effective with bedtime than morning dosing, and for dihydropyridine derivatives bedtime dosing significantly reduces risk of peripheral edema. The renin-angiotensin-aldosterone system is highly circadian rhythmic and activates during nighttime sleep. Accordingly, evening/bedtime ingestion of the angiotensin-converting enzyme inhibitors (ACEIs) benazepril, captopril, enalapril, lisinopril, perindopril, quinapril, ramipril, spirapril, trandolapril, and zofenopril exerts more marked effect on the asleep than awake systolic (SBP) and diastolic (DBP) BP means. Likewise, the bedtime, in comparison with morning, ingestion schedule of the angiotensin-II receptor blockers (ARBs irbesartan, olmesartan, telmisartan, and valsartan exerts greater therapeutic effect on asleep BP, plus significant increase in the sleep-time relative BP decline, with the additional benefit, independent of drug terminal half-life, of converting the 24-h BP profile into a more normal dipping pattern. This is the case also for the bedtime versus upon-awakening regimen of combination ARB-CCB, ACEI-CCB, and ARB-diuretic medications. The chronotherapy of conventional hypertension medications

  19. Differences in Topographical Pressure Pain Sensitivity Maps of the Scalp Between Patients With Migraine and Healthy Controls.

    Science.gov (United States)

    Barón, Johanna; Ruiz, Marina; Palacios-Ceña, María; Madeleine, Pascal; Guerrero, Ángel L; Arendt-Nielsen, Lars; Fernández-de-Las-Peñas, César

    2017-02-01

    To investigate differences in topographical pressure pain sensitivity maps of the scalp between patients with migraine and healthy controls considering the chronicity (episodic/chronic) and side (strictly unilateral/bilateral) of the symptoms. It seems that the trigeminal area is sensitized in migraine. No study has investigated topographical pressure sensitivity maps of the scalp in patients with migraine. Pressure pain thresholds (PPTs) were assessed from 21 points distributed over the scalp in 86 patients with episodic migraine, 76 with chronic migraine, and 42 healthy age and matched healthy controls in a blinded design. Topographical pressure pain sensitivity maps based on interpolation of the PPTs were constructed. Clinical features of migraine, anxiety, and depression (Hospital Anxiety and Depression Scale, HADS) were collected. The multivariate ANCOVA revealed significant differences in PPT between points (F = 55.674; P migraine groups than in healthy controls in all points (P migraine (P > .335) except for Fp1 (P = .045) and Fp2 (P = .017) points where subjects with chronic migraine had lower PPTs than those with episodic migraine; (3) no differences between bilateral/unilateral migraine (P > .417). An anterior to posterior gradient was found, with the lowest PPTs located in frontal regions and the highest PPTs in occipital areas (all groups, P migraine exhibited generalized pressure pain hypersensitivity in the head as compared to healthy controls and that hypersensitivity was similar between episodic/chronic and unilateral/bilateral migraine. Topographical pressure pain sensitivity maps revealed an anterior to posterior gradient of pressure pain sensitivity in both migraine and control groups. © 2016 American Headache Society.

  20. Attachment of MEM piezoresistive silicon pressure sensor dies using different adhesives

    Directory of Open Access Journals (Sweden)

    Jović Vesna B.

    2011-01-01

    Full Text Available This paper gives comparison and discussion of adhesives used for attachment of silicon piezoresistive pressure sensor dies. Special attention is paid on low pressure sensor dies because of their extreme sensitivity on stresses, which can arise from packaging procedure and applied materials. Commercially available adhesives “Scotch Weld 2214 Hi-Temp” from “3M Co.” and “DM2700P/H848” from “DIEMAT”, USA, were compared. First of them is aluminum filled epoxy adhesive and second is low melting temperature (LMT glass paste. Comparing test results for low pressure sensor chips we found that LMT glass (glass frit is better adhesive for this application. Applying LMT glass paste minimizes internal stresses caused by disagreement of coefficients of thermal expansions between sensor die and housing material. Also, it minimizes stresses introduced during applying external loads in the process of pressure measuring. Regarding the measurements, for the sensors installed with filled epoxy paste, resistor for compensation of temperature offset change had negative values in all cases, which means that linear temperature compensation, of sensors installed this way, would be impossible. In the sensors installed with LMT glass paste, all results, without exception, were in their common limits (values, which give the possibility of passive temperature compensation. Furthermore, LMT glass attachment can broaden temperature operating range of MEM silicon pressure sensors towards higher values, up to 120 ºC.

  1. Blood pressure and hemodynamics: Mayer waves in different phases of ovarian and menstrual cycle in women.

    Science.gov (United States)

    Lutsenko, O I; Kovalenko, S O

    2017-05-04

    The goal of the research is to investigate the special effect of ovarian-menstrual cycle phases on the level of women's blood pressure and characteristics of Mayer waves. 77 women aged 18-19 were tested under condition close to the state of basal metabolism in follicular phase (I), ovulation (II) and luteal phase (III) of ovarian-menstrual cycle. In phases II and III, the increase of mean and diastolic blood pressure level, in comparison with phase I in the prone position at rest and with psycho-emotional loading, were observed. The distinctions between variation parameters of R-R interval duration, stroke volume and its synchronization in phases II and III, in comparison with phase I, were observed in the prone position at rest, during tilt-test and with psycho-emotional loading. The substantial level of relationship between the power of Mayer waves and mean and diastolic blood pressure, mainly in phase I under conditions of all types, is observed. The maximum peak amplitude of stroke volume spectrogram is associated with pressure levels in the range of 0.04-0.15 Hz (rho from -0.33 to -0.64). The obtained results indicate the possible participation of spontaneous baroreflex sensitivity characteristics in keeping blood pressure level in women.

  2. Comparison of Diesel Spray Combustion in Different High-temperature, High-pressure Facilities

    DEFF Research Database (Denmark)

    Pickett, Lyle M.; Genzale, Caroline L.; Bruneaux, Gilles

    2010-01-01

    Diesel spray experimentation at controlled high-temperature and high-pressure conditions is intended to provide a more fundamental understanding of diesel combustion than can be achieved in engine experiments. This level of understanding is needed to develop the high-fidelity multi-scale CFD models...... boundary conditions at these unique facilities. Performing experiments at the same high-temperature, high-pressure operating conditions is an objective of the Engine Combustion Network (http://www.ca.sandia.gov/ECN/), which seeks to leverage the research capabilities and advanced diagnostics of all...... that will be used to optimize future engine designs. Several spray chamber facilities capable of high-temperature, high-pressure conditions typical of engine combustion have been developed, but because of the uniqueness of each facility, there are uncertainties about their operation. For this paper, we describe...

  3. Numerical simulation and experimental investigation of Ti-6Al-4V melted by CW fiber laser at different pressures

    Science.gov (United States)

    Tabassum, Aasma; Zhou, Jie; Han, Bing; Ni, Xiao-wu; Sardar, Maryam

    2017-07-01

    The interaction of continuous wave (CW) fiber laser with Ti-6Al-4V alloy is investigated numerically and experimentally at different laser fluence values and ambient pressures of N2 atmosphere to determine the melting time threshold of Ti-6Al-4V alloy. A 2D-axisymmetric numerical model considering heat transfer and laminar flow is established to describe the melting process. The simulation results indicate that material melts earlier at lower pressure (8.0 Pa) than at higher pressure (8.8×104 Pa) in several milliseconds with the same laser fluence. The experimental results demonstrate that the melting time threshold at high laser fluence (above 1.89×108 W/m2) is shorter for lower pressure (vacuum), which is consistent with the simulation. While the melting time threshold at low laser fluence (below 1.89×108 W/m2) is shorter for higher pressure. The possible aspects which can affect the melting process include the increased heat loss induced by the heat conduction between the metal surface and the ambient gas with the increased pressure, and the absorption variation of the coarse surface resulted from the chemical reaction.

  4. a Comprehensive Model for Capillary Pressure Difference across a Drop/bubble Flowing Through a Constricted Capillary

    Science.gov (United States)

    Liang, Mingchao; Wei, Junhong; Han, Hongmei; Fu, Chengguo; Liu, Jianjun

    2015-09-01

    The capillary pressure is one of the crucial parameters in many science and engineering applications such as composite materials, interface science, chemical engineering, oil exploration, etc. The drop/bubble formation and its mechanisms that affect the permeability of porous media have steadily attracted much attention in the past. When a drop/bubble moves from a larger capillary to a smaller one, it is often obstructed by an additional pressure difference caused by the capillary force. In this paper, a comprehensive model is derived for the capillary pressure difference when a drop/bubble flows through a constricted capillary, i.e. a geometrically constricted passage with an abrupt change in radius. The proposed model is expressed as a function of the smaller capillary radius, pore-throat ratio, contact angle, surface tension and length of the drop/bubble in the smaller capillary. The model predictions are compared with the available experimental data, and good agreement is found between them.

  5. Serum albumin--a non-saturable carrier

    DEFF Research Database (Denmark)

    Brodersen, R; Honoré, B; Larsen, F G

    1984-01-01

    The shape of binding isotherms for sixteen ligands to human serum albumin showed no signs of approaching saturation at high ligand concentrations. It is suggested that ligand binding to serum albumin is essentially different from saturable binding of substrates to enzymes, of oxygen to haemoglobi...

  6. Multi-spectral imaging of oxygen saturation

    Science.gov (United States)

    Savelieva, Tatiana A.; Stratonnikov, Aleksander A.; Loschenov, Victor B.

    2008-06-01

    The system of multi-spectral imaging of oxygen saturation is an instrument that can record both spectral and spatial information about a sample. In this project, the spectral imaging technique is used for monitoring of oxygen saturation of hemoglobin in human tissues. This system can be used for monitoring spatial distribution of oxygen saturation in photodynamic therapy, surgery or sports medicine. Diffuse reflectance spectroscopy in the visible range is an effective and extensively used technique for the non-invasive study and characterization of various biological tissues. In this article, a short review of modeling techniques being currently in use for diffuse reflection from semi-infinite turbid media is presented. A simple and practical model for use with a real-time imaging system is proposed. This model is based on linear approximation of the dependence of the diffuse reflectance coefficient on relation between absorbance and reduced scattering coefficient. This dependence was obtained with the Monte Carlo simulation of photon propagation in turbid media. Spectra of the oxygenated and deoxygenated forms of hemoglobin differ mostly in the red area (520 - 600 nm) and have several characteristic points there. Thus four band-pass filters were used for multi-spectral imaging. After having measured the reflectance, the data obtained are used for fitting the concentration of oxygenated and free hemoglobin, and hemoglobin oxygen saturation.

  7. Age-specific differences between conventional and ambulatory daytime blood pressure values

    DEFF Research Database (Denmark)

    Conen, David; Aeschbacher, Stefanie; Thijs, Lutgarde

    2014-01-01

    Mean daytime ambulatory blood pressure (BP) values are considered to be lower than conventional BP values, but data on this relation among younger individuals <50 years are scarce. Conventional and 24-hour ambulatory BP were measured in 9550 individuals not taking antihypertensive treatment from ...

  8. Rayleigh-Brillouin scattering profiles of air at different temperatures and pressures

    NARCIS (Netherlands)

    Gu, Z.; Witschas, B.; van der Water, W.; Ubachs, W.M.G.

    2013-01-01

    Rayleigh-Brillouin (RB) scattering profiles for air have been recorded for the temperature range from 255 to 340 K and the pressure range from 640 to 3300 mbar, covering the conditions relevant for the Earth's atmosphere and for planned atmospheric light detection and ranging (LIDAR) missions. The

  9. [Postoperative blood pressure alterations after carotid endarterectomy : Implications of different reconstruction methods].

    Science.gov (United States)

    Celi de la Torre, J A; Skrypnik, D A; Vinogradov, R A; Böckler, D; Demirel, S

    2017-08-25

    Postoperative blood pressure alterations after carotid endarterectomy (CEA) are associated with an increased risk of morbidity and mortality. To outline the influence of the two commonly used surgical reconstruction techniques, conventional CEA with patch plasty (C-CEA) and eversion CEA (E-CEA), as well as the innovative carotid sinus-preserving eversion CEA (SP-E-CEA) technique on postoperative hemodynamics, taking the current scientific knowledge into consideration. Assessment of the current clinical and scientific evidence on each operative technique found in the PubMed (NLM) database ranging from 1974 to 2017, excluding case reports. A total of 34 relevant papers as well as 1 meta-analysis, which scientifically dealt with the described topic were identified. The results of the studies and the meta-analysis showed that E‑CEA correlates with an impairment of local baroreceptor functions as well as with an elevated need for vasodilators in the early postoperative phase, whereas C‑CEA and SP-E-CEA seem to have a more favorable effect on the postoperative blood pressure. The CEA technique influences the postoperative blood pressure regulation, irrespective of the operative technique used. Accordingly, close blood pressure monitoring is recommended at least during the postoperative hospital stay. Further studies are mandatory to evaluate the importance of SP-E-CEA as an alternative to the classical E‑CEA.

  10. THE ANTIPROTEINURIC EFFECTS OF BLOOD-PRESSURE-LOWERING AGENTS - DIFFERENCES BETWEEN NONDIABETICS AND DIABETICS

    NARCIS (Netherlands)

    DEJONG, PE; HEEG, JE; APPERLOO, AJ; DEZEEUW, D

    1992-01-01

    The mechanism of the antiproteinuric effect of angiotensin-converting enzyme (ACE) inhibitors in diabetic and nondiabetic renal disease is as yet unknown. A meta-analysis of studies on the effects of ACE inhibitors and other antihypertensive drugs on proteinuria, blood pressure, and renal

  11. Retinal oxygen saturation before and after glaucoma surgery.

    Science.gov (United States)

    Nitta, Eri; Hirooka, Kazuyuki; Shimazaki, Takeru; Sato, Shino; Ukegawa, Kaori; Nakano, Yuki; Tsujikawa, Akitaka

    2017-08-01

    This study compared retinal vessel oxygen saturation before and after glaucoma surgery. Retinal oxygen saturation in glaucoma patients was measured using a non-invasive spectrophotometric retinal oximeter. Adequate image quality was found in 49 of the 108 consecutive glaucoma patients recruited, with 30 undergoing trabeculectomy, 11 EX-PRESS and eight trabeculotomy. Retinal oxygen saturation measurements in the retinal arterioles and venules were performed at 1 day prior to and at approximately 10 days after surgery. Statistical analysis was performed using a Student's t-test. After glaucoma surgery, intraocular pressure (IOP) decreased from 19.8 ± 7.7 mmHg to 9.0 ± 5.7 mmHg (p glaucoma surgery had an effect on the retinal venous oxygen saturation. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  12. Estimated Trans-Lamina Cribrosa Pressure Differences in Low-Teen and High-Teen Intraocular Pressure Normal Tension Glaucoma: The Korean National Health and Nutrition Examination Survey.

    Directory of Open Access Journals (Sweden)

    Si Hyung Lee

    Full Text Available To investigate the association between estimated trans-lamina cribrosa pressure difference (TLCPD and prevalence of normal tension glaucoma (NTG with low-teen and high-teen intraocular pressure (IOP using a population-based study design.A total of 12,743 adults (≥ 40 years of age who participated in the Korean National Health and Nutrition Examination Survey (KNHANES from 2009 to 2012 were included. Using a previously developed formula, cerebrospinal fluid pressure (CSFP in mmHg was estimated as 0.55 × body mass index (kg/m2 + 0.16 × diastolic blood pressure (mmHg-0.18 × age (years-1.91. TLCPD was calculated as IOP-CSFP. The NTG subjects were divided into two groups according to IOP level: low-teen NTG (IOP ≤ 15 mmHg and high-teen NTG (15 mmHg < IOP ≤ 21 mmHg groups. The association between TLCPD and the prevalence of NTG was assessed in the low- and high-teen IOP groups.In the normal population (n = 12,069, the weighted mean estimated CSFP was 11.69 ± 0.04 mmHg and the weighted mean TLCPD 2.31 ± 0.06 mmHg. Significantly higher TLCPD (p < 0.001; 6.48 ± 0.27 mmHg was found in the high-teen NTG compared with the normal group. On the other hand, there was no significant difference in TLCPD between normal and low-teen NTG subjects (p = 0.395; 2.31 ± 0.06 vs. 2.11 ± 0.24 mmHg. Multivariate logistic regression analysis revealed that TLCPD was significantly associated with the prevalence of NTG in the high-teen IOP group (p = 0.006; OR: 1.09; 95% CI: 1.02, 1.15, but not the low-teen IOP group (p = 0.636. Instead, the presence of hypertension was significantly associated with the prevalence of NTG in the low-teen IOP group (p < 0.001; OR: 1.65; 95% CI: 1.26, 2.16.TLCPD was significantly associated with the prevalence of NTG in high-teen IOP subjects, but not low-teen IOP subjects, in whom hypertension may be more closely associated. This study suggests that the underlying mechanisms may differ between low-teen and high-teen NTG patients.

  13. Experimental studies on the K{beta}/K{alpha} intensity ratio of Zn at different thickness and pressure

    Energy Technology Data Exchange (ETDEWEB)

    Icelli, Orhan E-mail: orhan_icelli@hotmail.com; Erzeneoglu, Salih

    2004-01-15

    K{beta}/K{alpha} intensity ratios of Zn were measured at a photon excitation energy of 59.5 keV using a high-resolution Si(Li) detector for several thickness at different pressure. Present results were compared with theoretical data and other experimental values. The results were in good agreement theoretical values based on Hartree-Fock theory.

  14. Multifractal multiscale dfa of cardiovascular time series: Differences in complex dynamics of systolic blood pressure, diastolic blood pressure and heart rate.

    Science.gov (United States)

    Castiglioni, Paolo; Lazzeroni, Davide; Brambilla, Valerio; Coruzzi, Paolo; Faini, Andrea

    2017-07-01

    The heart-rate fractal dynamics can be assessed by Detrended Fluctuation Analysis (DFA), originally proposed for estimating a short-term coefficient, α1 (for scales n≤12 beats), and a long-term coefficient α2 (for longer scales). Successively, DFA was extended to provide a multiscale α, i.e. a continuous function of n, α(n); or a multifractal α, i.e. a function of the order q of the fluctuations moment, α(q). Very recently, a multifractal-multiscale DFA was proposed for evaluating multifractality at different scales separately. Aim of this work is to describe the multifractal multiscale dynamics of three cardiovascular signals often recorded beat by beat in physiological and clinical settings: systolic blood pressure (SBP), diastolic blood pressure (DBP) and pulse interval (PI, inverse of the heart rate). We recorded SBP, DBP and PI for at least 90' in 65 healthy volunteers at rest, and adapted the previously proposed multifractal multiscale DFA to estimate α as function of the temporal scale, τ, between 15 and 450 s, and of the order q, between -5 and 5. We report, for the first time: 1) substantial differences among α(q,τ) surfaces of PI, SBP and DBP; 2) a strong dependency of the degree of multifractality on the temporal scale.

  15. Pneumatic measuring method of tank volumes using low pressure differences; Pneumatische Bestimmung von Behaeltervolumina mit Hilfe kleiner Druckdifferenzen

    Energy Technology Data Exchange (ETDEWEB)

    Riedel, Joerg; Neumann, Jann [Physikalisch-Technische Bundesanstalt (PTB), Braunschweig (Germany). Fachbereich 1.5

    2011-07-01

    The inner volume of a tank can be determined by means of conventional methods (geometric measurement, measurement of equivalent liquid quantities) if the tank can be accessed appropriately. It can be problematical for permanently installed or geometrically complex tanks. In this paper an alternative and known method is investigated which allows the measurement with the aid of a reference tank and the knowledge of the gas pressures in the tanks. The investigations with low pressure differences are focussed on the statistical uncertainty of the method. (orig.)

  16. Comparison of different levels of positive expiratory pressure on chest wall volumes in healthy children and patients with fibrosis

    OpenAIRE

    Brilhante, Silvia Angélica; Florêncio, Rêcio Bento; Gualdi, Lucien Peroni; Resqueti,Vanessa Regiane; Aliverti,Andrea; Andrade, Armele de Fátima Dornelas de; Fregonezi, Guilherme Augusto de Freitas

    2017-01-01

    ABSTRACT Positive Expiratory Pressure (PEP) improves lung function, however, PEP-induced changes are not fully established. The aim of this study was to assess the acute effects of different PEP levels on chest wall volumes and the breathing pattern in children with Cystic Fibrosis (CF). Anthropometric data, lung function values, and respiratory muscle strength were collected. Chest wall volumes were assessed by Optoelectronic plethysmography at rest and during the use of different PEP levels...

  17. SEISMIC EVALUATION OF HYDROCARBON SATURATION IN DEEP-WATER RESERVOIRS

    Energy Technology Data Exchange (ETDEWEB)

    Michael Batzle; D-h Han; R. Gibson; Huw James

    2005-01-22

    During this last quarter of the ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' project (Grant/Cooperative Agreement DE-FC26-02NT15342), we have moved forward on several fronts, including data acquisition as well as analysis and application. During this quarter we have: (1) Completed our site selection (finally); (2) Measured fluid effects in Troika deep water sand sample; (3) Applied the result to Ursa ''fizz gas'' zone; (4) Compared thin layer property averaging on AVO response; (5) Developed target oriented NMO stretch correction; (6) Examined thin bed effects on A-B crossplots; and (7) Begun incorporating outcrop descriptive models in seismic forward models. Several factors can contribute to limit our ability to extract accurate hydrocarbon saturations in deep water environments. Rock and fluid properties are one factor, since, for example, hydrocarbon properties will be considerably different with great depths (high pressure) when compared to shallow properties. Significant over pressure, on the other hand will make the rocks behave as if they were shallower. In addition to the physical properties, the scale and tuning will alter our hydrocarbon indicators. Reservoirs composed of thin bed effects will broaden the reflection amplitude distribution with incident angle. Normal move out (NMO) stretch corrections based on frequency shifts can be applied to offset this effect. Tuning will also disturb the location of extracted amplitudes on AVO intercept and gradient (A-B) plots. Many deep water reservoirs fall this tuning thickness range. Our goal for the remaining project period is to systematically combine and document these various effects for use in deep water exploration.

  18. Seismic Evaluation of Hydorcarbon Saturation in Deep-Water Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Michael Batzle; D-h Han; R. Gibson; Huw James

    2005-10-31

    During this last quarter of the ''Seismic Evaluation of Hydrocarbon Saturation in Deep-Water Reservoirs'' project (Grant/Cooperative Agreement DE-FC26-02NT15342), we have moved forward on several fronts, including data acquisition as well as analysis and application. During this quarter we have: (1) Completed our site selection (finally); (2) Measured fluid effects in Troika deep water sand sample; (3) Applied the result to Ursa ''fizz gas'' zone; (4) Compared thin layer property averaging on AVO response; (5) Developed target oriented NMO stretch correction; (6) Examined thin bed effects on A-B crossplots; and (7) Begun incorporating outcrop descriptive models in seismic forward models. Several factors can contribute to limit our ability to extract accurate hydrocarbon saturations in deep water environments. Rock and fluid properties are one factor, since, for example, hydrocarbon properties will be considerably different with great depths (high pressure) when compared to shallow properties. Significant over pressure, on the other hand will make the rocks behave as if they were shallower. In addition to the physical properties, the scale and tuning will alter our hydrocarbon indicators. Reservoirs composed of thin bed effects will broaden the reflection amplitude distribution with incident angle. Normal move out (NMO) stretch corrections based on frequency shifts can be applied to offset this effect. Tuning will also disturb the location of extracted amplitudes on AVO intercept and gradient (A-B) plots. Many deep water reservoirs fall this tuning thickness range. Our goal for the remaining project period is to systematically combine and document these various effects for use in deep water exploration.

  19. Compensation of Actuator’s Saturation by Using Fuzzy Logic and Imperialist Competitive Algorithm in a System with PID Controller

    Directory of Open Access Journals (Sweden)

    Abbas Ali Zamani

    2012-07-01

    Full Text Available Physical systems always include constraints and limits. Usually, the limits and constraints, in the control systems, are appeared as temperature and pressure limits or pumps capacity. One of the existing limits in the systems with PID controller is associated with the actuator’s saturation limits. With the saturating of the actuator, the controller’s output and plant’s input will be different and the output signal of controller do not lead the system and their states could not update correctly where this issue makes the system response undesirable. In this paper, by adding a fuzzy compensator that it’s parameters are tuned using imperialist competitive algorithm, the actuator saturation is prevented and the important parameters of the system response, such as setting time and overshoot, are improved.

  20. Titration effectiveness of two autoadjustable continuous positive airway pressure devices driven by different algorithms in patients with obstructive sleep apnoea.

    Science.gov (United States)

    Damiani, Mario Francesco; Quaranta, Vitaliano Nicola; Tedeschi, Ersilia; Drigo, Riccardo; Ranieri, Teresa; Carratù, Pierluigi; Resta, Onofrio

    2013-08-01

    Nocturnal application of continuous positive airway pressure (CPAP) is the standard treatment for patients with obstructive sleep apnoea (OSA). Determination of the therapeutic pressure (CPAP titration) is usually performed by a technician in the sleep laboratory during attended polysomnography. One possible alternative to manual titration is automated titration. Indeed, during the last 15 years, devices have been developed that deliver autoadjustable CPAP (A-CPAP). The aim of the present study was to compare the titration effectiveness of two A-CPAP devices using different flow-based algorithms in patients with OSA. This is a randomized study; 79 subjects underwent two consecutive unattended home A-CPAP titration nights with two different devices (Autoset Resmed; Remstar Auto Respironics); during the third and the fourth night, patients underwent portable monitoring in the sleep laboratory during fixed CPAP at the A-CPAP recommended pressure. Bland Altman plots showed good agreement between the recommended median and maximal pressure levels obtained with the two devices. A significant improvement was observed in all the sleep parameters by both A-CPAP machines to a similar degree. It was observed that the two A-CPAP devices using different algorithms are equally effective in initial titration of CPAP. © 2013 The Authors. Respirology © 2013 Asian Pacific Society of Respirology.

  1. Numerical investigation on pressure fluctuations in centrifugal compressor with different inlet guide vanes pre-whirl angles

    Science.gov (United States)

    Wang, Y. C.; Shi, M.; Cao, S. L.; Li, Z. H.

    2013-12-01

    The pressure fluctuations in a centrifugal compressor with different inlet guide vanes (IGV) pre-whirl angles were investigated numerically, as well as the pre-stress model and static structural of blade. The natural frequency was evaluated by pre-stress model analysis. The results show that, the aero-dynamic pressure acting on blade surface is smaller than rotation pre-stress, which wouldn't result in large deformation of blade. The natural frequencies with rotation pre-stress are slightly higher than without rotation pre-stress. The leading mechanism of pressure fluctuations for normal conditions is the rotor-stator (IGVs) interaction, while is serious flow separations for conditions that are close to surge line. A few frequency components in spectra are close to natural frequency, which possibly result in resonant vibration if amplitude is large enough, which is dangerous for compressor working, and should be avoided.

  2. Theory of graphene saturable absorption

    Science.gov (United States)

    Marini, A.; Cox, J. D.; García de Abajo, F. J.

    2017-03-01

    Saturable absorption is a nonperturbative nonlinear optical phenomenon that plays a pivotal role in the generation of ultrafast light pulses. Here we show that this effect emerges in graphene at unprecedentedly low light intensities, thus opening avenues to new nonlinear physics and applications in optical technology. Specifically, we theoretically investigate saturable absorption in extended graphene by developing a semianalytical nonperturbative single-particle approach, describing electron dynamics in the atomically-thin material using the two-dimensional Dirac equation for massless Dirac fermions, which is recast in the form of generalized Bloch equations. By solving the electron dynamics nonperturbatively, we account for both interband and intraband contributions to the intensity-dependent saturated conductivity and conclude that the former dominates regardless of the intrinsic doping state of the material. We obtain results in qualitative agreement with atomistic quantum-mechanical simulations of graphene nanoribbons including electron-electron interactions, finite-size, and higher-band effects. Remarkably, such effects are found to affect mainly the linear absorption, while the predicted saturation intensities are in good quantitative agreement in the limit of extended graphene. Additionally, we find that the modulation depth of saturable absorption in graphene can be electrically manipulated through an externally applied gate voltage. Our results are relevant for the development of graphene-based optoelectronic devices, as well as for applications in mode-locking and random lasers.

  3. Ion dynamics of a laser produced aluminium plasma at different ambient pressures

    Science.gov (United States)

    Sankar, Pranitha; Shashikala, H. D.; Philip, Reji

    2018-01-01

    Plasma is generated by pulsed laser ablation of an Aluminium target using 1064 nm, 7 ns Nd:YAG laser pulses. The spatial and temporal evolution of the whole plasma plume, as well as that of the ionic (Al2+) component present in the plume, are investigated using spectrally resolved time-gated imaging. The influence of ambient gas pressure on the expansion dynamics of Al2+ is studied in particular. In vacuum (10-5 Torr, 10-2 Torr) the whole plume expands adiabatically and diffuses into the ambient. For higher pressures in the range of 1-10 Torr plume expansion is in accordance with the shock wave model, while at 760 Torr the expansion follows the drag model. On the other hand, the expansion dynamics of the Al2+ component, measured by introducing a band pass optical filter in the detection system, fits to the shock wave model for the entire pressure range of 10-2 Torr to 760 Torr. The expansion velocities of the whole plume and the Al2+ component have been measured in vacuum. These dynamics studies are of potential importance for applications such as laser-driven plasma accelerators, ion acceleration, pulsed laser deposition, micromachining, laser-assisted mass spectrometry, ion implantation, and light source generation.

  4. Effect of high hydrostatic pressure on the supramolecular structure of corn starch with different amylose contents.

    Science.gov (United States)

    Yang, Zhi; Swedlund, Peter; Hemar, Yacine; Mo, Guang; Wei, Yanru; Li, Zhihong; Wu, Zhonghua

    2016-04-01

    Corn starches with amylose contents ranging from 0 to 80% were suspended in 60 wt% water or ethanol and subjected to high hydrostatic pressure (HHP) up to 600 MPa. The impact of HHP treatment on the granule morphology, lamellae structures, and crystalline characteristics were examined with a combination of SAXS, WAXS and optical microscopy. All starch dispersed in water showed a decrease in area of the lamellar peak in the SAXS data at q∼0.6 nm(-1). The lamellae thickness (d) increased for pressurized waxy, normal, and Gelose80 corn starches, suggesting water is forced into starch lamellae during HHP. However, for Gelose50 corn starch, the d remained constant over the whole pressure range and light microscopy showed no obvious granule swelling. WAXS studies demonstrated that HHP partially converted A-type starches (waxy and normal corn) to starches with a faint B-type pattern while starches with a B+V-type pattern (Gelose50 and Gelose80), were not affected by HHP. All corn starches suspended in ethanol showed no detectable changes in either granule morphology, or the fractal, the lamellae, and the crystalline structures. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. EFFECT OF DIFFERENT COMPACTION PRESSURE AND DIFFERENT SINTERING ROUTE ON K0.5NA0.5NBO₃ PHYSICAL AND DIELECTRIC PROPERTIES

    Directory of Open Access Journals (Sweden)

    Nor Fatin Khairah Bahanurddin

    2016-07-01

    Full Text Available Alkaline niobate known as K0.5Na0.5NbO3 (KNN, a lead-free piezoelectric ceramic was synthesized via a solid state reaction method. The samples were compacted at different pressures (100, 200, 300 and 400 MPa and sintered using two different techniques (conventional furnace and hot isostatic pressing (HIP. The effect of compaction pressure and sintering technique on physical and dielectric properties was studied. The optimum compaction pressure (300 MPa and sintering via HIP (at 1080 °C for 30 min increased the density and grain size ( range 30 - 300 nm and improved its dielectric properties. Therefore, the combination of suitable compaction pressure and sintering technique has produced larger grain size and higher density of KNN which resulted in outstanding dielectric properties. At room temperature, excellent values of ε r (5517.35 and tan δ (0.954, recorded at 1 MHz were measured for the KNN300HIP sample with highest density (4.4885 g/cm³.

  6. Central venous oxygen saturation during hypovolaemic shock in humans

    DEFF Research Database (Denmark)

    Madsen, P; Iversen, H; Secher, N H

    1993-01-01

    We compared central venous oxygen saturation and central venous pressure (CVP) as indices of the effective blood volume during 50 degrees head-up tilt (anti-Trendelenburg's position) induced hypovolaemic shock in eight healthy subjects. Head-up tilt increased thoracic electrical impedance from 31...

  7. Intra-aneurysm sac pressure measurements after endovascular aneurysm repair: differences between shrinking, unchanged, and expanding aneurysms with and without endoleaks.

    Science.gov (United States)

    Dias, Nuno V; Ivancev, Krassi; Malina, Martin; Resch, Timothy; Lindblad, Bengt; Sonesson, Björn

    2004-06-01

    Our objective was to study intra-aneurysm pressure after endovascular aneurysm repair (EVAR) in shrinking, unchanged, and expanding abdominal aortic aneurysms (AAAs) with and without endoleaks. Direct intra-aneurysm sac pressure measurement (DISP) by percutaneous translumbar puncture of the AAA under fluoroscopic guidance was performed 46 times during the follow-up of 37 patients (30 men; median age, 73 years [range, 58-82 years]; AAA diameter: median, 60 mm [range, 48-84 mm]). Three patients were included in two different groups because DISP was performed more than once with different indications. Tip-pressure sensors mounted on 0.014-inch guidewires were used for simultaneous measurement of systemic and AAA sac pressures. Mean pressure index (MPI) was calculated as the percentage of mean intra-aneurysm pressure relative to the simultaneous mean intra-aortic pressure. Median MPI was 19% in shrinking (11 patients), 30% in unchanged (10 patients), and 59% in expanding (9 patients) aneurysms without endoleaks. Pulse pressure was also higher in expanding (10 mm Hg) compared with shrinking (2 mm Hg; P pressure reduction. Intra-aneurysm sac pressure measurement is an important adjunctive for EVAR evaluation, possibly allowing early detection of failures. High pressure is associated with AAA expansion and low pressure with shrinkage. Type II endoleaks can be responsible for AAA pressurization, and successful embolization appears to result in pressure reduction.

  8. A Design Method of Saturation Test Image Based on CIEDE2000

    Directory of Open Access Journals (Sweden)

    Yang Yang

    2012-01-01

    Full Text Available In order to generate color test image consistent with human perception in aspect of saturation, lightness, and hue of image, we propose a saturation test image design method based on CIEDE2000 color difference formula. This method exploits the subjective saturation parameter C′ of CIEDE2000 to get a series of test images with different saturation but same lightness and hue. It is found experimentally that the vision perception has linear relationship with the saturation parameter C′. This kind of saturation test image has various applications, such as in the checking of color masking effect in visual experiments and the testing of the visual effects of image similarity component.

  9. Foot pressure analysis of adults with flat and normal feet at different gait speeds on an ascending slope.

    Science.gov (United States)

    Kim, Myoung-Kwon

    2015-12-01

    [Purpose] This study was conducted to determine the difference in foot pressures between flat and normal feet at different gait speeds on an ascending slope. [Subjects] This study enrolled 30 adults with normal (n=15) and flat feet (n=15), with ages from 21 to 30 years old, who had no history of neurological disorders or gait problems. A treadmill was used for the analysis of kinematic features during gait, using a slope of 10%, and gait velocities of slow, normal, and fast. [Methods] A foot pressure analyzer was used to measure changes in foot pressure. [Results] Compared to the normal subjects, the foot pressure of the flatfoot subjects showed a significant increase in the 2-3rd metatarsal region with increasing gait speed, whereas there were significant decreases in the 1st toe and 1st metatarsal regions with increasing gait speed. [Conclusion] The body weight of adults with flatfoot was concentrated on the 2-3rd metatarsal region during the stance phase and increased with walking speed on the ascending slope due to weakening of function of the medial longitudinal arch.

  10. Measurement of blood pressure for the diagnosis and management of hypertension in different ethnic groups: one size fits all.

    Science.gov (United States)

    Gill, Paramjit; Haque, M Sayeed; Martin, Una; Mant, Jonathan; Mohammed, Mohammed A; Heer, Gurdip; Johal, Amanpreet; Kaur, Ramandeep; Schwartz, Claire; Wood, Sally; Greenfield, Sheila M; McManus, Richard J

    2017-02-08

    Hypertension is a major risk factor for cardiovascular disease and prevalence varies by ethnic group. The diagnosis and management of blood pressure are informed by guidelines largely based on data from white populations. This study addressed whether accuracy of blood pressure measurement in terms of diagnosis of hypertension varies by ethnicity by comparing two measurement modalities (clinic blood pressure and home monitoring) with a reference standard of ambulatory BP monitoring in three ethnic groups. Cross-sectional population study (June 2010 - December 2012) with patients (40-75 years) of white British, South Asian and African Caribbean background with and without a previous diagnosis of hypertension recruited from 28 primary care practices. The study compared the test performance of clinic BP (using various protocols) and home-monitoring (1 week) with a reference standard of mean daytime ambulatory measurements using a threshold of 140/90 mmHg for clinic and 135/85 mmHg for out of office measurement. A total of 551 participants had complete data of whom 246 were white British, 147 South Asian and 158 African Caribbean. No consistent difference in accuracy of methods of blood pressure measurement was observed between ethnic groups with or without a prior diagnosis of hypertension: for people without hypertension, clinic measurement using three different methodologies had high specificity (75-97%) but variable sensitivity (33-65%) whereas home monitoring had sensitivity of 68-88% and specificity of 64-80%. For people with hypertension, detection of a raised blood pressure using clinic measurements had sensitivities of 34-69% with specificity of 73-92% and home monitoring had sensitivity (81-88%) and specificity (55-65%). For people without hypertension, ABPM remains the choice for diagnosing hypertension compared to the other modes of BP measurement regardless of ethnicity. Differences in accuracy of home monitoring and clinic monitoring (higher sensitivity

  11. Relationship Between Brain Pulsatility and Cerebral Perfusion Pressure: Replicated Validation Using Different Drivers of CPP Change.

    Science.gov (United States)

    Calviello, Leanne A; de Riva, Nicolás; Donnelly, Joseph; Czosnyka, Marek; Smielewski, Peter; Menon, David K; Zeiler, Frederick A

    2017-12-01

    Determination of relationships between transcranial Doppler (TCD)-based spectral pulsatility index (sPI) and pulse amplitude (AMP) of intracranial pressure (ICP) in 2 groups of severe traumatic brain injury (TBI) patients (a) displaying plateau waves and (b) with unstable mean arterial pressure (MAP). We retrospectively reviewed patients with severe TBI and continuous TCD monitoring displaying either plateau waves or unstable MAP from 1992 to 1998. We utilized linear and nonlinear regression techniques to describe both cohorts: cerebral perfusion pressure (CPP) versus AMP, CPP versus sPI, mean ICP versus ICP AMP, mean ICP versus sPI, and AMP versus sPI. Nonlinear regression techniques were employed to analyze the relationships with CPP. In plateau wave and unstable MAP patients, CPP versus sPI displayed an inverse nonlinear relationship (R 2 = 0.820 vs. R 2 = 0.610, respectively), with the CPP versus sPI relationship best modeled by the following function in both cases: PI = a + (b/CPP). Similarly, in both groups, CPP versus AMP displayed an inverse nonlinear relationship (R 2 = 0.610 vs. R 2 = 0.360, respectively). Positive linear correlations were displayed in both the plateau wave and unstable MAP cohorts between: ICP versus AMP, ICP versus sPI, AMP versus sPI. There is an inverse relationship through nonlinear regression between CPP versus AMP and CPP versus sPI display. This provides evidence to support a previously-proposed model of TCD pulsatility index. ICP shows a positive linear correlation with AMP and sPI, which is also established between AMP and sPI.

  12. Chronic fatigue syndrome and idiopathic intracranial hypertension: Different manifestations of the same disorder of intracranial pressure?

    Science.gov (United States)

    Higgins, J Nicholas P; Pickard, John D; Lever, Andrew M L

    2017-08-01

    Though not discussed in the medical literature or considered in clinical practice, there are similarities between chronic fatigue syndrome and idiopathic intracranial hypertension (IIH) which ought to encourage exploration of a link between them. The cardinal symptoms of each - fatigue and headache - are common in the other and their multiple other symptoms are frequently seen in both. The single discriminating factor is raised intracranial pressure, evidenced in IIH usually by the sign of papilloedema, regarded as responsible for the visual symptoms which can lead to blindness. Some patients with IIH, however, do not have papilloedema and these patients may be clinically indistinguishable from patients with chronic fatigue syndrome. Yet IIH is rare, IIH without papilloedema (IIHWOP) seems rarer still, while chronic fatigue syndrome is common. So are the clinical parallels spurious or is there a way to reconcile these conflicting observations? We suggest that it is a quirk of clinical measurement that has created this discrepancy. Specifically, that the criteria put in place to define IIH have led to a failure to appreciate the existence, clinical significance or numerical importance of patients with lower level disturbances of intracranial pressure. We argue that this has led to a grossly implausible distortion of the epidemiology of IIH such that the milder form of the illness (IIHWOP) is seen as less common than the more severe and that this would be resolved by recognising a connection with chronic fatigue syndrome. We hypothesise, therefore, that IIH, IIHWOP, lesser forms of IIH and an undetermined proportion of chronic fatigue cases are all manifestations of the same disorder of intracranial pressure across a spectrum of disease severity, in which this subset of chronic fatigue syndrome would represent the most common and least severe and IIH the least common and most extreme. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  13. Epidemiological investigation into the prevalence of abnormal inter-arm blood pressure differences among different ethnicities in Xinjiang, China.

    Directory of Open Access Journals (Sweden)

    Ling Sun

    Full Text Available The prevalence of and risk factors for IAD among different ethnicity groups was unknown. Our aim was to investigate the prevalence of and risk factors for IAD among Han, Uygur and Kazakh ethnicities in Xinjiang. China.In total, 14,618 adult participants (7,799 males and 6,819 females were recruited from the Cardiovascular Risk Survey. A 4-stage stratified cluster random sampling method was used. The participants' personal information and medical history were assessed by questionnaire. IAD was diagnosed by a noninvasive arteriosclerosis analyzer.The prevalence of abnormal IAD among the general population was 14.3%, with 12.5% in the Han, 14.9% in the Uygur, and 16.4% in the Kazakh populations. The prevalence of abnormal IAD among the hypertensive population was 19.4%, with 17.0% in the Han, 18.1% in the Uygur, and 22.7% in the Kazakh populations. The prevalence of abnormal IAD increased with age (all P 0.05. Multivariate logistic regression analysis showed that age more than 45 years, obesity and hypertriglyceridemia were significantly associated with a higher prevalence of IAD. There were different risk factors for abnormal IAD in different ethnicities. Middle or old age, obesity, ABI and diabetes mellitus were risk factors for the Han population, smoking was a risk factor in the Uygur population, and obesity and PAD were risk factors in the Kazakh population.The prevalence of abnormal IAD in the Kazakh participants was higher than that in the Han and Uygur populations among both the general population and the hypertensive population in Xinjiang, China. The main risk factors of IAD were age, obesity, and triglyceride levels. Different ethnicities had different kinds of risk factors for IAD.

  14. Epidemiological investigation into the prevalence of abnormal inter-arm blood pressure differences among different ethnicities in Xinjiang, China.

    Science.gov (United States)

    Sun, Ling; Zou, Ting; Wang, Bao-Zhu; Liu, Fen; Yuan, Qing-Hua; Ma, Yi-Tong; Ma, Xiang

    2018-01-01

    The prevalence of and risk factors for IAD among different ethnicity groups was unknown. Our aim was to investigate the prevalence of and risk factors for IAD among Han, Uygur and Kazakh ethnicities in Xinjiang. China. In total, 14,618 adult participants (7,799 males and 6,819 females) were recruited from the Cardiovascular Risk Survey. A 4-stage stratified cluster random sampling method was used. The participants' personal information and medical history were assessed by questionnaire. IAD was diagnosed by a noninvasive arteriosclerosis analyzer. The prevalence of abnormal IAD among the general population was 14.3%, with 12.5% in the Han, 14.9% in the Uygur, and 16.4% in the Kazakh populations. The prevalence of abnormal IAD among the hypertensive population was 19.4%, with 17.0% in the Han, 18.1% in the Uygur, and 22.7% in the Kazakh populations. The prevalence of abnormal IAD increased with age (all P 0.05). Multivariate logistic regression analysis showed that age more than 45 years, obesity and hypertriglyceridemia were significantly associated with a higher prevalence of IAD. There were different risk factors for abnormal IAD in different ethnicities. Middle or old age, obesity, ABI and diabetes mellitus were risk factors for the Han population, smoking was a risk factor in the Uygur population, and obesity and PAD were risk factors in the Kazakh population. The prevalence of abnormal IAD in the Kazakh participants was higher than that in the Han and Uygur populations among both the general population and the hypertensive population in Xinjiang, China. The main risk factors of IAD were age, obesity, and triglyceride levels. Different ethnicities had different kinds of risk factors for IAD.

  15. The Effects of Different Insufflation Pressures on Liver Functions Assessed with LiMON on Patients Undergoing Laparoscopic Cholecystectomy

    Directory of Open Access Journals (Sweden)

    H. Barıs Eryılmaz

    2012-01-01

    Full Text Available Purpose. Laparoscopic cholecystectomy has been accepted as an alternative to laparotomy, but there is still controversy regarding the effects of pneumoperitoneum on splanchnic and hepatic perfusion. We assessed the effects of different insufflation pressures on liver functions by using indocyanine green elimination tests (ICG-PDR. Methods. We analyzed 43 patients who were scheduled for laparoscopic cholecystectomy. The patients were randomly allocated to two groups. In Group I, the operation was performed using 10 mmHg pressure pneumoperitoneum. In Group II, 14 mmHg pressure pneumoperitoneum was used. The ICG-PDR measurements were made after induction (ICG-PDR 1 and after the end of the operation (ICG-PDR 2. Serum aspartate aminotransferase (AST, alanine aminotransferase (ALT, and total bilirubin levels were all recorded preoperatively, 1 hour, and postoperative 24 hours after surgery. Results. The ICG-PDR 1 values for Groups I and II were as follows: 26.78±4.2% per min versus 26.01±2.4% per min (>0.05. ICG-PDR 2 values were found to be 25.63±2.1% per min in Group I versus 19.06±2.2% per min in Group II (0.05. Conclusion. In conclusion, the results show that 14 mmHg pressure pneumoperitoneum decreased the blood flow to the liver and increased postoperative 1st-hour serum AST and ALT levels. We think that 10 mmHg pressure pneumoperitoneum is superior to 14 mmHg pressure pneumoperitoneum in laparoscopic cholecystectomy.

  16. THE ROLE OF DIFFERENT RHEOLOGICAL MODELS IN ACCURACY OF PRESSURE LOSS PREDICTION

    Directory of Open Access Journals (Sweden)

    Katarina Simon

    2004-12-01

    Full Text Available Hydraulics play an important function in many oil field operations including drilling, completion, fracturing, acidizing, workover and production. The standard API methods for drilling fluid hydraulics assume either power law or Bingham plastic rheological model. These models and corresponding hydraulic calculations do provide a simple way for fair estimates of hydraulics for conventional vertical wells using simple drilling fluids, such as bentonite fluids. However, nowdays with many wells drilled deep, slim or horizontal using complex muds with unusual behaviour (such as tested MMH mud, it is necessary to use appropriate rheological model for mathematical modelling of fluid behaviour. Oil and gas reservoirs in Croatia have been under production for quite a while and the probability to discover new deposits of hydrocarbons is rather small. Therefore attempts have been made to maintain the gas and oil exploitation at the present level. One of possible ways to meet this target is re-entry wells drilling. The diameter of such wells in reservoir is smaller than 0,1524 m (6 in. Accurate modelling of annular pressure losses becomes therefore an important issue, particularly in cases where a small safety margin exists between optimal drilling parameters and wellbore stability, what is the case in re-entry wells. The objective of the paper is to show the influence of well geometry and accuracy of fluid rheological properties modelling to the distribution of pressure losses in a slimhole well.

  17. The elastic constants and anisotropy of superconducting MgCNi3 and CdCNi3 under different pressure

    KAUST Repository

    Feng, Huifang

    2013-11-23

    The second-order elastic constants (SOECs) and third-order elastic constants (TOECs) of MgCNi3 and CdCNi3 are presented by using first-principles methods combined with homogeneous deformation theory. The Voigt-Reuss-Hill (VRH) approximation are used to calculate the bulk modulus B, shear modulus G, averaged Young\\'s modulus E and Poisson\\'s ratio ν for polycrystals and these effective modulus are consistent with the experiments. The SOECs under different pressure of MgCNi3 and CdCNi3 are also obtained based on the TOECs. Furthermore, the Zener anisotropy factor, Chung-Buessem anisotropy index, and the universal anisotropy index are used to describe the anisotropy of MgCNi3 and CdCNi3. The anisotropy of Young\\'s modulus of single-crystal under different pressure is also presented. © 2013 Springer Science+Business Media New York.

  18. Effect of the shapes of the oscillometric pulse amplitude envelopes and their characteristic ratios on the differences between auscultatory and oscillometric blood pressure measurements.

    Science.gov (United States)

    Amoore, John N; Vacher, Emilie; Murray, Ian C; Mieke, Stephan; King, Susan T; Smith, Fiona E; Murray, Alan

    2007-10-01

    Oscillometric noninvasive blood pressure (NIBP) devices determine pressure by analysing the oscillometric waveform using empirical algorithms. Many algorithms analyse the waveform by calculating the systolic and diastolic characteristic ratios, which are the amplitudes of the oscillometric pulses in the cuff at, respectively, the systolic and diastolic pressures, divided by the peak pulse amplitude. A database of oscillometric waveforms was used to study the influences of the characteristic ratios on the differences between auscultatory and oscillometric measurements. Two hundred and forty-three oscillometric waveforms and simultaneous auscultatory blood pressures were recorded from 124 patients at cuff deflation rates of 2-3 mmHg/s. A simulator regenerated the waveforms, which were presented to two NIBP devices, the Omron HEM-907 [OMRON Europe B.V. (OMCE), Hoofddorp, The Netherlands] and the GE ProCare 400 (GE Healthcare, Tampa, Florida, USA). For each waveform, the paired systolic and paired diastolic pressure differences between device measurements and auscultatory reference pressures were calculated. The systolic and diastolic characteristic ratios, corresponding to the reference auscultatory pressures of each oscillometric waveform stored in the simulator, were calculated. The paired differences between NIBP measured and auscultatory reference pressures were compared with the characteristic ratios. The mean and standard deviations of the systolic and diastolic characteristic ratios were 0.49 (0.11) and 0.72 (0.12), respectively. The systolic pressures recorded by both devices were lower (negative paired pressure difference) than the corresponding auscultatory pressures at low systolic characteristic ratios, but higher than the corresponding auscultatory pressures at high systolic pressures. Conversely, the differences between the paired diastolic pressure differences were higher at low diastolic characteristic ratios, compared with those at high diastolic

  19. Neopuff T-piece resuscitator mask ventilation: Does mask leak vary with different peak inspiratory pressures in a manikin model?

    Science.gov (United States)

    Maheshwari, Rajesh; Tracy, Mark; Hinder, Murray; Wright, Audrey

    2017-08-01

    The aim of this study was to compare mask leak with three different peak inspiratory pressure (PIP) settings during T-piece resuscitator (TPR; Neopuff) mask ventilation on a neonatal manikin model. Participants were neonatal unit staff members. They were instructed to provide mask ventilation with a TPR with three PIP settings (20, 30, 40 cm H2 O) chosen in a random order. Each episode was for 2 min with 2-min rest period. Flow rate and positive end-expiratory pressure (PEEP) were kept constant. Airway pressure, inspiratory and expiratory tidal volumes, mask leak, respiratory rate and inspiratory time were recorded. Repeated measures analysis of variance was used for statistical analysis. A total of 12 749 inflations delivered by 40 participants were analysed. There were no statistically significant differences (P > 0.05) in the mask leak with the three PIP settings. No statistically significant differences were seen in respiratory rate and inspiratory time with the three PIP settings. There was a significant rise in PEEP as the PIP increased. Failure to achieve the desired PIP was observed especially at the higher settings. In a neonatal manikin model, the mask leak does not vary as a function of the PIP when the flow rate is constant. With a fixed rate and inspiratory time, there seems to be a rise in PEEP with increasing PIP. © 2017 Paediatrics and Child Health Division (The Royal Australasian College of Physicians).

  20. Properties of multi-laminated plywood produced with Hovenia dulcis Thunb. and Pinus elliottii wood under different pressing pressures

    Directory of Open Access Journals (Sweden)

    Ezaquel Bednarczuk

    2017-05-01

    Full Text Available This study aimed at evaluating the effect of different pressing pressures and the influence of the wood features on the properties of plywood produced with sapwood and heartwood Hovenia dulcis combined with Pinus elliottii. To support the discussion, the anatomical and physical characterizations of the wood were carried out. The panels were produced by applying three different press pressures (0.88, 1.18 and 1.47 MPa and with six combinations of wood veneers. Phenol-formaldehyde resin was employed, 160 g m-2 in a simple line and 35% solid content. The anatomical analysis revealed that the sapwood is more permeable than the H. dulcis heartwood. The H. dulcis wood basic density it was higher than that of the P. elliottii. Increased press pressure raised the values of the apparent density, thickness swelling and thickness swelling plus recovery of the plywood and water absorption reduction. The panels produced with H. dulcis veneers presented higher apparent density, MOR, MOE and bonding line resistance, as well as lower water absorption and moisture content, than those produced with P. elliottii veneers. No difference was noticed regarding the plywood properties when the main effects were evaluated in relation to the use of H. dulcis heartwood and sapwood veneers.

  1. Pulse Distortion in Saturated Fiber Optical Parametric Chirped Pulse Amplification

    DEFF Research Database (Denmark)

    Lali-Dastjerdi, Zohreh; Da Ros, Francesco; Rottwitt, Karsten

    2012-01-01

    Fiber optical parametric chirped pulse amplification is experimentally compared for different chirped pulses in the picosecond regime. The amplified chirped pulses show distortion appearing as pedestals after recompression when the amplifier is operated in saturation....

  2. Saturation Detection-Based Blocking Scheme for Transformer Differential Protection

    Directory of Open Access Journals (Sweden)

    Byung Eun Lee

    2014-07-01

    Full Text Available This paper describes a current differential relay for transformer protection that operates in conjunction with a core saturation detection-based blocking algorithm. The differential current for the magnetic inrush or over-excitation has a point of inflection at the start and end of each saturation period of the transformer core. At these instants, discontinuities arise in the first-difference function of the differential current. The second- and third-difference functions convert the points of inflection into pulses, the magnitudes of which are large enough to detect core saturation. The blocking signal is activated if the third-difference of the differential current is larger than the threshold and is maintained for one cycle. In addition, a method to discriminate between transformer saturation and current transformer (CT saturation is included. The performance of the proposed blocking scheme was compared with that of a conventional harmonic blocking method. The test results indicate that the proposed scheme successfully discriminates internal faults even with CT saturation from the magnetic inrush, over-excitation, and external faults with CT saturation, and can significantly reduce the operating time delay of the relay.

  3. Effects of different hydrostatic pressure on lesions in ex vivo bovine livers induced by high intensity focused ultrasound.

    Science.gov (United States)

    He, Min; Zhong, Zhiqiang; Li, Xing; Gong, Xiaobo; Wang, Zhibiao; Li, Faqi

    2017-05-01

    It is well-known that acoustic cavitation associated with the high intensity focused ultrasound (HIFU) treatment often would change the morphology and size of lesions in its treatment. In most studies reported in literature, high ambient hydrostatic pressure was used to suppress the cavitation completely. Investigation of the effects by varying the ambient hydrostatic pressure (Pstat) is still lacking. In this paper, the effects of HIFU on lesions in ex vivo bovine liver specimens under various Pstat are systematically investigated. A 1MHz HIFU transducer, with an aperture diameter of 70mm and a focal length of 55mm, was used to generate two groups US exposure of different acoustic intensities and exposure time (6095W/cm(2)×8s and 9752W/cm(2)×5s), while keeping the same acoustic energies per unit area (48760J/cm(2)). The peak acoustic negative pressures (p(-)) of the two groups were p1(-)=9.58MPa and p2(-)=10.82MPa, respectively, with the difference pd(-)=p2(-)-p1(-)=1.24MPa. A passive cavitation detection (PCD) was used to monitor the ultrasonic cavitation signal during exposure of the two groups. The US exposures were done under the following ambient hydrostatic pressures, Pstat: atmospheric pressure, 0.5MPa, 1.0MPa, 1.5MPa, 2.0MPa, 2.5MPa and3.0MPa, respectively. The result of PCD showed that there was a statistically significant increase above background noise level in broadband emissions at dose of 9752W/cm(2)×5s, but not at dose of 6095W/cm(2)×8s under atmospheric pressure; i.e., the acoustic cavitation took place for p2(-) but not for p1(-) when under atmospheric pressure. The results also showed that there was no statistically difference of the morphology and size of lesions for 6095W/cm(2)×8s exposure under the aforementioned different ambient hydrostatic pressures. But the lesions generated at 9752W/cm(2)×5s exposure under Pstat=atmospheric pressure, 0.5MPa, 1.0MPa (all of them are less than pd(-)), were larger than those under 1.5MPa, 2.0MPa, 2

  4. Noise and saturation properties of semiconductor quantum dot optical amplifiers

    DEFF Research Database (Denmark)

    Berg, Tommy Winther; Mørk, Jesper

    2002-01-01

    We present a detailed theoretical analysis of quantum dot optical amplifiers. Due to the presence of a reservoir of wetting layer states, the saturation and noise properties differ markedly from bulk or QW amplifiers and may be significantly improved.......We present a detailed theoretical analysis of quantum dot optical amplifiers. Due to the presence of a reservoir of wetting layer states, the saturation and noise properties differ markedly from bulk or QW amplifiers and may be significantly improved....

  5. Comparative evaluation of pressure generated on a simulated maxillary oral analog by impression materials in custom trays of different spacer designs: An in vitro study

    Directory of Open Access Journals (Sweden)

    Sakshi Chopra

    2016-01-01

    Full Text Available Introduction: Literature reveals that masticatory load on denture bearing tissues through complete dentures should be maximum on primary stress bearing areas and least on relief area in accordance with the histology of underlying tissues. A study to validate the existing beliefs was planned to compare the pressure on mucosa using selective pressure technique and minimal pressure technique, with the incorporation of two different impression materials utilizing the pressure sensors during secondary impression procedure. Materials and Methods: The study was performed using a maxillary analog. Three pressure sensors were imbedded in the oral analog, one in the mid palatine area and the other two in the right and left ridge crest. Custom trays of two different configurations were fabricated. The two impression materials tested were light body and zinc oxide eugenol. A total of 40 impressions were made. A constant weight of 1 kg was placed, and the pressure was recorded as initial and end pressures. Results: A significant difference in the pressure produced using different impression materials was found (P < 0.001. Light body vinyl polysiloxane produced significantly lesser pressure than zinc oxide eugenol impression materials. The presence of relief did affect the magnitude of pressure at various locations. Conclusion: All impression materials produced pressure during maxillary edentulous impression making. Tray modification is an important factor in changing the amount of pressure produced. The impression materials used also had a significant role to play on the pressures acting on the tissues during impression procedure. Clinical Implication: Light body VPS impression material may be recommended to achieve minimal pressure on the denture bearing tissues in both selective as well as minimal pressure techniques.

  6. THERMODYNAMIC MODEL FOR HIGH PRESSURE PHASE BEHAVIOR OF CARBON DIOXIDE IN SEVERAL PHYSICAL SOLVENTS AT DIFFERENT TEMPERATURES

    Directory of Open Access Journals (Sweden)

    Arkan J. Hadi

    2013-05-01

    Full Text Available In the present study a thermodynamic model for prediction of gas-liquid equilibrium at high pressures and different temperatures prepared for the binary systems of carbon dioxide (1 with each of the one of the liquid physical solvents (2 (sulfolane, n-methyl-2-pyrrolidone and propylene carbonate using Peng-Robenson equation of state (PR-EOS with different mixing rules to show the effect of the type of mixing rule used.Comparison of the experimental phase equilibrium data in the literature with the results of the model showed very good representation for some mixing rules and good for the others.

  7. Saturated Dispersive Extinction Theory of Red Shift

    Science.gov (United States)

    Wang, Ling Jun

    2012-03-01

    The Dispersive Extinction Theory (DET) proposed by WangfootnotetextWang, Ling Jun, Physics Essays, 18, No. 2, (2005). offers an alternative to the Big Bang. According to DET, the cosmic red shift is caused by the dispersive extinction of the star light during the propagation from the stars to the earth, instead of being caused by the Doppler shift due to the expansion of the universe.footnotetextHubble, E., Astrophys. J. 64, 321 (1926).^,footnotetextHubble, E., The Realm of the Nebulae, (Yale University Press, New Haven, 1936). DET allows an infinite, stable, non expanding universe, and is immune of the fundamental problems inherent to the Big Bang such as the horizon problem, the extreme violation of the conservation of mass, energy and charge, and the geocentric nature which violates the principle of relativity.footnotetextWang, Ling Jun, Physics Essays, 20, No. 2, (2007). The scenario dealt with in Reference (1) is a one in which the extinction by the space medium is not saturated. This work deals with a different scenario when the extinction is saturated. The saturated extinction causes limited energy loss, and the star light can travel a much greater distance than in the unsaturated scenario.

  8. Life history, habitat saturation and the evolution of fecundity and survival altruism.

    Science.gov (United States)

    Lion, Sébastien; Gandon, Sylvain

    2010-06-01

    Hamilton's rule provides a general description of the conditions for the evolution of altruism. But altruism can take different forms depending on which life-history trait is affected by the helping behavior (fecundity vs. survival helping). In particular, these different forms of helping may have very different demographic consequences, which may feed back on evolution. We examine the interplay between various forms of helping and demography in viscous populations with empty sites. A key component of our analysis is the local density of empty sites experienced by a focal individual, which provides a measure of habitat saturation. Habitat saturation is shown to have contrasting effects depending on (1) whether the physiological costs and benefits of helping affect fecundity, survival or both; and (2) whether the costs of helping are paid in a density-dependent or density-independent manner. For a given level of habitat saturation and with density-dependent reproduction, we find that the conditions for the evolution of helping should be more favorable in the survival altruism life cycle with a cost on fecundity, and more stringent in the fecundity altruism life cycle with a cost on survival. More generally, our analysis stresses the importance of taking into account the feedback between population demography, life history, and kin selection when investigating the selective pressures on altruism.

  9. Different selection pressures give rise to distinct ethnic phenomena : a functionalist framework with illustrations from the Peruvian Altiplano.

    Science.gov (United States)

    Moya, Cristina; Boyd, Robert

    2015-03-01

    Many accounts of ethnic phenomena imply that processes such as stereotyping, essentialism, ethnocentrism, and intergroup hostility stem from a unitary adaptation for reasoning about groups. This is partly justified by the phenomena's co-occurrence in correlational studies. Here we argue that these behaviors are better modeled as functionally independent adaptations that arose in response to different selection pressures throughout human evolution. As such, different mechanisms may be triggered by different group boundaries within a single society. We illustrate this functionalist framework using ethnographic work from the Quechua-Aymara language boundary in the Peruvian Altiplano. We show that different group boundaries motivate different ethnic phenomena. For example, people have strong stereotypes about socioeconomic categories, which are not cooperative units, whereas they hold fewer stereotypes about communities, which are the primary focus of cooperative activity. We also show that, despite the cross-cultural importance of ethnolinguistic boundaries, the Quechua-Aymara linguistic distinction does not strongly motivate any of these intergroup processes.

  10. The elastic properties, generalized stacking fault energy and dissociated dislocations in MgB2 under different pressure

    KAUST Repository

    Feng, Huifang

    2013-05-31

    The 〈112̄0〉 perfect dislocation in MgB2 is suggested to dissociate into two partial dislocations in an energy favorable way 〈112̄0〉 → 1/2 〈112̄0〉 + SF + 1/2 〈112̄0〉. This dissociation style is a correction of the previous dissociation 〈1000〉 → 1/3 〈11̄00〉 SF + 1/3 〈 2100〉proposed by Zhu et al. to model the partial dislocations and stacking fault observed by transmission electron microscopy. The latter dissociation results in a maximal stacking fault energy rather than a minimal one according to the generalized stacking fault energy calculated from first-principles methods. Furthermore, the elastic constants and anisotropy of MgB2 under different pressure are investigated. The core structures and mobilities of the 〈112̄0〉 dissociated dislocations are studied within the modified Peierls-Nabarro (P-N) dislocation theory. The variational method is used to solve the modified P-N dislocation equation and the Peierls stress is also determined under different pressure. High pressure effects on elastic anisotropy, core structure and Peierls stress are also presented. © 2013 Springer Science+Business Media New York.

  11. Surface Wind Speed Patterns from Synoptic Pressure Series employing different soft-computing algorithms

    Science.gov (United States)

    Kirchner Bossi, N.; Salcedo Sanz, S.; Carro Calvo, L.; Prieto, L.; Garcia Herrera, R.

    2012-04-01

    Two methods for establishing a daily wind-characterizing surface flux classification are introduced and compared in this work. They are based on several geostrophic flow indexes and have been derived from a NCEP/NCAR reanalysis of Mean Sea Level Pressure data (MSLP). In the task of parametrization and design of wind pattern classifiers, several soft-computing tools were developed: an evolutionary algorithm and a greedy-based technique were chosen to tackle the geostrophic flow vs. real wind approaching issue. Both algorithms work by optimizing the borders between clusters in the velocity space of the geostrophic flow (training experiment). Then the cluster configuration is assessed by linking the synoptic geostrophic wind signal with the corresponding real wind data (testing experiment) obtained from measurement towers at six wind farms located in Spain. The results obtained through these approaches were compared with those obtained by a widely reviewed, daily circulation weather types (WT) method, outperforming the later in all the instances considered. The main application of the proposed techniques is the accurate reconstruction of observational wind speed data series, which represents an interesting problem to consider at wind farms specially in periods without wind measurements available.

  12. Numerical Simulation of Geostress and Pore Pressure Evolution around Oil or Water Well under Different Injection-Production Ratio

    Directory of Open Access Journals (Sweden)

    Liu Jian-jun

    2013-01-01

    Full Text Available Geostress evolution in the process of oil field development can directly influence wellbore stability. Therefore, it is significant to strengthen the research of the evolution rule for well drilling and casing protection. Considering the interaction between reservoir seepage and stress fields, a mathematical model to characterize the stress evolution around wellbore was built. Using the FEM Software ABAQUS, through numerical simulation, the authors studied the evolution features of pore pressure and stress changes with time under different injection-production ratio, which disclosed the dynamic change regulation of pore pressure and stress of surrounding rock nearby the injection and production wells. These results may have implications in the treatment of wellbore stability and optimizing the injection and production processes during oil and gas production.

  13. Differences in perioperative femoral and radial arterial blood pressure in neonates and infants undergoing cardiac surgery requiring cardiopulmonary bypass.

    Science.gov (United States)

    Cho, Hwa Jin; Lee, Sang Hoon; Jeong, In Seok; Yoon, Nam Sik; Ma, Jae Sook; Ahn, Byoung Hee

    Several reports claim that blood pressure (BP) in the radial artery may underestimate the accurate BP in critically ill patients. Here, the authors evaluated differences in mean blood pressure (MBP) between the radial and femoral artery during pediatric cardiac surgery to determine the effectiveness of femoral arterial BP monitoring. The medical records of children under 1 year of age who underwent open-heart surgery between 2007 and 2013 were retrospectively reviewed. Radial and femoral BP were measured simultaneously, and the differences between these values were analyzed at various times: after catheter insertion, after the initiation of cardiopulmonary bypass (CPB-on), after aortic cross clamping (ACC), after the release of ACC, after weaning from CPB, at arrival in the intensive care unit (ICU), and every 6h during the first day in the ICU. A total of 121 patients who underwent open-heart surgery met the inclusion criteria. During the intraoperative period, from the beginning to the end of CPB, radial MBPs were significantly lower than femoral MBPs at each time-point measured (p60min, odds ratio: 7.47) was a risk factor for lower radial pressure. However, discrepancies between these two values disappeared after arrival in the ICU. There was no incidence of ischemic complications associated with the catheterization of both arteries. The authors suggest that femoral arterial pressure monitoring can be safely performed, even in neonates, and provides more accurate BP values during CPB-on periods, and immediately after weaning from CPB, especially when CPB time was greater than 60min. Copyright © 2017 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

  14. Femtosecond Yb:YAG laser using semiconductor saturable absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Hoenninger, C.; Zhang, G.; Keller, U. [Ultrafast Laser Physics, Institute of Quantum Electronics, Swiss Federal Institute of Technology, ETH Hoenggerberg--HPT, CH-8093 Zuerich (Switzerland); Giesen, A. [Institut fuer Strahlwerkzeuge, Universitaet Stuttgart, Pfaffenwaldring 43, D-70569 Stuttgart (Germany)

    1995-12-01

    We demonstrate a passively mode-locked femtosecond Yb:YAG laser using different semiconductor saturable absorber devices, a high-finesse and a low-finesse antiresonant Fabry{endash}Perot saturable absorber. We achieved pulses as short as 540 fs with dispersion compensation and 1.7-ps pulses without dispersion compensation. We also mode locked the laser at either 1.03 or 1.05 {mu}m by adjusting the band gap and antiresonance wavelength design of the antiresonant Fabry{endash}Perot saturable absorber. {copyright} {ital 1995 Optical Society of America.}

  15. Slow light in saturable absorbers

    OpenAIRE

    Macke, Bruno; Ségard, Bernard

    2008-01-01

    International audience; In connection with the experiments recently achieved on doped crystals, biological samples, doped optical fibers and semiconductor heterostructures, we revisit the theory of the propagation of a pulse-modulated light in a saturable absorber. Explicit analytical expressions of the transmitted pulse are obtained, enabling us to determine the parameters optimizing the time-delay of the transmitted pulse with respect to the incident pulse. We finally compare the maximum fr...

  16. Saturation of Van Allen's belts

    CERN Document Server

    Le Bel, E

    2002-01-01

    The maximum number of electrons that can be trapped in van Allen's belts has been evaluated at CEA-DAM more precisely than that commonly used in the space community. The modelization that we have developed allows to understand the disagreement (factor 50) observed between the measured and predicted electrons flux by US satellites and theory. This saturation level allows sizing-up of the protection on a satellite in case of energetic events. (authors)

  17. Different types of interactions of links in artificial and natural ecosystems under anthropogenic pressure

    Science.gov (United States)

    Somova, Lydia; Pisman, Tamara; Mikheeva, Galina; Pechurkin, Nickolay

    The life of organisms in an ecosystem depends not only on abiotic factors, but also on the interaction of organisms in which they come with each other. The study of mechanisms of the bioregulation based on ecological - biochemical interactions of ecosystem links is necessary to know the ecosystem development, its stability, survival of ecosystem organisms. It is of high importance as for the creation of artificial ecosystems, and also for the study of natural ecosystems under anthropogenic pressure on them. To create well-functioning ecosystems is necessary to study and consider the basic types of relationships between organisms. The basic types of interactions between organisms have been studied with simple terrestrial and water ecosystems. 1. The interaction of microbiocenoses and plants were studied in experiments with agrocenoses. Microbiocenosis proposed for increase of productivity of plants and for obtaining ecologically pure production of plants has been created taking into account mutual relationships between species of microorganisms. 2. The experimental model of the atmosphere closed «autotroph - heterotroph» system in which heterotrophic link was the mixed population of yeasts (Candida utilis and Candida guilliermondii) was studied. The algae Chlorella vulgaris was used as an autotroph link. It was shown, that the competition result for heterotrophic link depended on strategy of populations of yeast in relation to a substrate and oxygen utilization. 3. As a result of experimental and theoretical modelling of a competition of algae Chlorella vulgaris and Scenedesmus quadricauda at continuous cultivation, the impossibility of their coexistence in the conditions of limitation on nitrogen was shown. 4. Pray-predator interactions between algae (Chlorella vulgaris, Scenedesmus quadricauda) and invertebrates (Paramecium caudatum, Brachionus plicatilis) were studied in experimental closed ecosystem. This work was partly supported by the Russian Foundation for

  18. Intraocular Pressure Measurements by Three Different Tonometers in Children with Aphakic Glaucoma and a Thick Cornea

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Razeghinejad

    2014-01-01

    Full Text Available Background: To evaluate the agreement in intraocular pressure (IOP measurements by Ocular Response Analyzer (ORA and Tono-Pen XL (TXL with the Goldmann Applanation Tonometer (GAT and to examine corneal biomechanical properties in aphakic glaucoma patients with a central corneal thickness (CCT >600 µ. Methods: Thirty-six eyes of aphakic glaucoma patients (group 1 and 40 eyes of normal children (group 2 were studied. The mean ORA and TXL IOP values were compared with the GAT-IOP values. Regression analyses were used to evaluate the associations between IOP and CCT, corneal hysteresis (CH, and corneal resistance factor (CRF. Bland-Altman plots were used to evaluate the agreement between the tonometers. Results: The mean±standard deviations of the age and male/female ratio were 16.58±5.44 and 15.75±5.04 years and 14/22 and 18/22 in group 1 and group 2, respectively. CCT in group 1 was 651.1±42 and in group 2 was 567.3±32.4. In group 1, the mean TXL (22.4, P=0.004, IOPcc (corneal compensated (27.8, P=0.005, and IOPg (Goldmann correlated values (28.1, P<0.0001 were greater than GAT-IOP (20.6. In group 2, only IOPg value (16.4 was higher than GAT-IOP (14.8, P=0.04. IOP reading of all the tonometers were positively and negatively associated with CRF and CH in the multiple regression analysis, respectively. Conclusion: The TXL had a greater agreement with the GAT, and the ORA overestimated IOP in aphakic glaucoma patients. The ORA and TXL seemed to be affected by CH and CRF.

  19. Rayleigh-Brillouin scattering profiles of air at different temperatures and pressures.

    Science.gov (United States)

    Gu, Ziyu; Witschas, Benjamin; van de Water, Willem; Ubachs, Wim

    2013-07-01

    Rayleigh-Brillouin (RB) scattering profiles for air have been recorded for the temperature range from 255 to 340 K and the pressure range from 640 to 3300 mbar, covering the conditions relevant for the Earth's atmosphere and for planned atmospheric light detection and ranging (LIDAR) missions. The measurements performed at a wavelength of λ=366.8 nm detect spontaneous RB scattering at a 90° scattering angle from a sensitive intracavity setup, delivering scattering profiles at a 1% rms noise level or better. The experimental results have been compared to a kinetic line-shape model, the acclaimed Tenti S6 model, considered to be most appropriate for such conditions, under the assumption that air can be treated as an effective single-component gas with temperature-scaled values for the relevant macroscopic transport coefficients. The elusive transport coefficient, the bulk viscosity η(b), is effectively derived by a comparing the measurements to the model, yielding an increased trend from 1.0 to 2.5×10(-5) kg·m(-1)·s(-1) for the temperature interval. The calculated (Tenti S6) line shapes are consistent with experimental data at the level of 2%, meeting the requirements for the future RB-scattering LIDAR missions in the Earth's atmosphere. However, the systematic 2% deviation may imply that the model has a limit to describe the finest details of RB scattering in air. Finally, it is demonstrated that the RB scattering data in combination with the Tenti S6 model can be used to retrieve the actual gas temperatures.

  20. Transition to Turbulent Dynamo Saturation

    Science.gov (United States)

    Seshasayanan, Kannabiran; Gallet, Basile; Alexakis, Alexandros

    2017-11-01

    While the saturated magnetic energy is independent of viscosity in dynamo experiments, it remains viscosity dependent in state-of-the-art 3D direct numerical simulations (DNS). Extrapolating such viscous scaling laws to realistic parameter values leads to an underestimation of the magnetic energy by several orders of magnitude. The origin of this discrepancy is that fully 3D DNS cannot reach low enough values of the magnetic Prandtl number Pm. To bypass this limitation and investigate dynamo saturation at very low Pm, we focus on the vicinity of the dynamo threshold in a rapidly rotating flow: the velocity field then depends on two spatial coordinates only, while the magnetic field consists of a single Fourier mode in the third direction. We perform numerical simulations of the resulting set of reduced equations for Pm down to 2 ×10-5. This parameter regime is currently out of reach to fully 3D DNS. We show that the magnetic energy transitions from a high-Pm viscous scaling regime to a low-Pm turbulent scaling regime, the latter being independent of viscosity. The transition to the turbulent saturation regime occurs at a low value of the magnetic Prandtl number, Pm ≃10-3 , which explains why it has been overlooked by numerical studies so far.

  1. SATURATED PICRIC ACID PREVENTS AUTOPHAGIA

    Directory of Open Access Journals (Sweden)

    V Rahimi-Movaghar

    2008-08-01

    Full Text Available "nThe dysesthesia and paresthesia that occurs in laboratory rats after spinal cord injury (SCI results in autophagia. This self-destructive behavior interferes with functional assessments in designed studies and jeopardizes the health of the injured rat. In this study, we evaluated role of saturated picric acid in the prevention of autophagia and self-mutilation. All rats were anesthetized with an intraperitoneal injection of a mixture of ketamine (100 mg/kg and xylazine (10 mg/kg for the SCI procedures. In the first 39 rats, no solution applied to the hind limbs, but in the next 26 cases, we smeared the saturated picric acid on the tail, lower extremities, pelvic, and abdomen of the rats immediately after SCI. In the rats without picric acid, 23 rats died following autophagia, but in the 26 rats with picric acid, there was no autophagia (P < 0.001. Picric acid side effects in skin and gastrointestinal signs such as irritation, redness and diarrhea were not seen in any rat. Saturated picric acid is a topical solution that if used appropriately and carefully, might be safe and effectively prevents autophagia and self-mutilation. When the solution is applied to the lower abdomen and limbs, we presume that its bitterness effectively prevents the rat from licking and biting the limb.

  2. A Study on Anthropometric Measurements, Blood Pressure, Blood Sugar and Food Intakes Among Different Social Status and Ethnicities

    Directory of Open Access Journals (Sweden)

    Jafarirad

    2016-09-01

    Full Text Available Background Metabolic syndrome is a disorder that increases the risk of cardiovascular disease and diabetes. Objectives The aim of the study was to evaluate some risk factors of the metabolic syndrome and food intakes among people who lived in Ahvaz City, Iran. Methods It was a filed study that was conducted on 211 subjects who participated in health exhibition. Socioeconomic status and ethnicity were asked by a general questionnaire. Weight, height, body mass index, waist circumference (WC and WC to hip circumference ratio (WHR were obtained. Blood sugar was measured by a glucometer. Systolic and diastolic blood pressures were obtained and dietary intakes were assessed by a brief instrument. Results There was a significant difference in weight, height, WC, WHR and systolic blood pressure among different jobs. Workers had more intakes of cake and sweets. Arab subjects had more intakes of bread and fishes and Persians more intakes of vegetables. Soda, chocolate and candy were more consumed by Kurd ethnicity. Conclusions Job may be accounted as an important effective socioeconomic factor related to metabolic syndrome risk factors; also different cultures due to different ethnicities may have an influence on lifestyle and dietary intakes.

  3. A sulfide-saturated lunar mantle?

    Science.gov (United States)

    Brenan, James M.; Mungall, James E.

    2017-04-01

    Although much work has been done to understand the controls on the sulfur content at sulfide saturation (SCSS) for terrestrial melt compositions, little information exists to evaluate the SCSS for the high FeO compositions typical of lunar magmas, and at the reduced conditions of the Moon's interior. Experiments were done to measure the SCSS for a model low Ti mare basalt with 20 wt% FeO at 1400oC as a function of fO2 and pressure. Synthetic lunar basalt was encapsulated along with stoichiometric FeS in capsules made from Fe-Ir alloy. The fO2 of the experiment can be estimated by the heterogeneous equilibrium: Femetal + 1 /2 O2 = FeOsilicate Variation in the metal composition, by addition of Ir, serves to change the fO2 of the experiment. Capsule compositions spanning the range Fe25Ir75 to Fe96Ir4 (at%) were synthesized by sintering of pressed powders under reducing conditions. Fe100 capsules were fabricated from pure Fe rod. For a melt with 20 wt% FeO, this range in capsule composition spans the fO2 interval of ˜IW-1 (Fe100, Fe96Ir4) to IW+2.2 (Fe25Ir75). Experiments were done over the pressure interval of 0.1 MPa to 2 GPa. Results for experiments involving Fe100capsules indicate that the SCSS decreases from ˜2000 ppm (0.1 MPa) to 700 ppm (2 GPa). Experiments done thus far at 1 GPa, involving the range of capsule compositions indicated, show a marked decrease in SCSS as the Fe content of the capsule increases (fO2 decreases). Complementary to the decrease in SCSS is a drop in the sulfur content of the coexisting sulfide melt, from ˜50 at% at ΔIW = +2.2 to ˜20 at% at ΔIW-1. In fact, both the composition of the sulfide melt and the SCSS are essentially indistinguishable for Fe96Ir4 and Fe100 compositions. Results thus far indicate that at reduced conditions and high pressure, the SCSS for high FeO lunar compositions is low, and overlaps with Apollo 11 melt inclusion data. Importantly, such low SCSS does not require Fe metal saturation, and suggests that some

  4. An efficient implicit-pressure/explicit- saturation-method-based shifting-matrix algorithm to simulate two-phase, immiscible flow in porous media with application to CO2 sequestration in the subsurface

    KAUST Repository

    Salama, Amgad

    2013-07-04

    The flow of two or more immiscible fluids in porous media is widespread, particularly in the oil industry. This includes secondary and tertiary oil recovery and carbon dioxide (CO2) sequestration. Accurate predictions of the development of these processes are important in estimating the benefits and consequences of the use of certain technologies. However, this accurate prediction depends--to a large extent--on two things. The first is related to our ability to correctly characterize the reservoir with all its complexities; the second depends on our ability to develop robust techniques that solve the governing equations efficiently and accurately. In this work, we introduce a new robust and efficient numerical technique for solving the conservation laws that govern the movement of two immiscible fluids in the subsurface. As an example, this work is applied to the problem of CO2 sequestration in deep saline aquifers; however, it can also be extended to incorporate more scenarios. The traditional solution algorithms to this problem are modeled after discretizing the governing laws on a generic cell and then proceed to the other cells within loops. Therefore, it is expected that calling and iterating these loops multiple times can take a significant amount of computer time. Furthermore, if this process is performed with programming languages that require repeated interpretation each time a loop is called, such as Matlab, Python, and others, much longer time is expected, particularly for larger systems. In this new algorithm, the solution is performed for all the nodes at once and not within loops. The solution methodology involves manipulating all the variables as column vectors. By use of shifting matrices, these vectors are shifted in such a way that subtracting relevant vectors produces the corresponding difference algorithm. It has been found that this technique significantly reduces the amount of central-processing-unit (CPU) time compared with a traditional

  5. Single-sided natural ventilation driven by wind pressure and temperature difference

    DEFF Research Database (Denmark)

    Larsen, Tine Steen; Heiselberg, Per

    2008-01-01

    -scale wind tunnel experiments have been made with the aim of making a new expression for calculation of the airflow rate in single-sided natural ventilation. During the wind tunnel experiments it was found that the dominating driving force differs between wind speed and temperature difference depending......Even though opening a window for ventilation of a room seems very simple, the flow that occurs in this situation is rather complicated. The amount of air going through the window opening will depend on the wind speed near the building, the temperatures inside and outside the room, the wind...

  6. Laser-induced breakdown spectroscopy on metallic samples at very low temperature in different ambient gas pressures

    Science.gov (United States)

    El-Saeid, R. H.; Abdelhamid, M.; Harith, M. A.

    2016-02-01

    Analysis of metals at very low temperature adopting laser-induced breakdown spectroscopy (LIBS) is greatly beneficial in space exploration expeditions and in some important industrial applications. In the present work, the effect of very low sample temperature on the spectral emission intensity of laser-induced plasma under both atmospheric pressure and vacuum has been studied for different bronze alloy samples. The sample was cooled down to liquid nitrogen (LN) temperature 77 K in a special vacuum chamber. Laser-induced plasma has been produced onto the sample surface using the fundamental wavelength of Nd:YAG laser. The optical emission from the plasma is collected by an optical fiber and analyzed by an echelle spectrometer combined with an intensified CCD camera. The integrated intensities of certain spectral emission lines of Cu, Pb, Sn, and Zn have been estimated from the obtained LIBS spectra and compared with that measured at room temperature. The laser-induced plasma parameters (electron number density Ne and electron temperature Te) were investigated at room and liquid nitrogen temperatures for both atmospheric pressure and vacuum ambient conditions. The results suggest that reducing the sample temperature leads to decrease in the emission line intensities under both environments. Plasma parameters were found to decrease at atmospheric pressure but increased under vacuum conditions.

  7. The effect of pressure on tricalcium silicate hydration at different temperatures and in the presence of retarding additives

    Energy Technology Data Exchange (ETDEWEB)

    Jupe, Andrew C.; Wilkinson, Angus P.; Funkhouser, Gary P. (Halliburton); (GIT)

    2012-07-25

    The hydration of tricalcium silicate (C{sub 3}S) is accelerated by pressure. However, the extent to which temperature and/or cement additives modify this effect is largely unknown. Time-resolved synchrotron powder diffraction has been used to study cement hydration as a function of pressure at different temperatures in the absence of additives, and at selected temperatures in the presence of retarding agents. The magnitudes of the apparent activation volumes for C{sub 3}S hydration increased with the addition of the retarders sucrose, maltodextrin, aminotri(methylenephosphonic acid) and an AMPS copolymer. Pressure was found to retard the formation of Jaffeite relative to the degree of C{sub 3}S hydration in high temperature experiments. For one cement slurry studied without additives, the apparent activation volume for C{sub 3}S hydration remained close to {approx} -28 cm{sup 3} mol{sup -1} over the range 25 to 60 C. For another slurry, there were possible signs of a decrease in magnitude at the lowest temperature examined.

  8. Properties of the pressure-induced extended-solid carbon monoxide under different synthesis and processing conditions

    Science.gov (United States)

    Dang, Nhan; Ciezak-Jenkins, Jennifer

    2017-06-01

    The discovery of the high-energy-density pressure-induced extended-solid/polymeric carbon monoxide (poly-CO) has opened a new paradigm of energetic materials. Considerable studies have been made to understand properties of poly-CO. However factors which control the morphology and meta-stability of recovered samples at ambient conditions have not been identified. In this presentation, we report the variations of morphology and meta-stability of poly-CO synthesized under different conditions in the GPa range. It has been found that the morphology and meta-stability of poly-CO depend on sample volume, rate of polymeric phase transition and additives. Poly-CO synthesized with a faster compression rate appears to be more structurally disordered and have higher rates of decomposition. Samples synthesized in a larger volume require either a longer time at elevated pressure or a higher pressure for the polymeric phase transitions to occur. Also, results of kinetic studies of photochemical reaction of CO at 4.5 GPa in presence of traces of H2 O, HCl (1M), and concentrated H2SO4 will be presented and influences of these additives on the morphology and meta-stability of polymeric CO will be discussed.

  9. Stability of different influenza subtypes: How can high hydrostatic pressure be a useful tool for vaccine development?

    Science.gov (United States)

    Dumard, Carlos Henrique; Barroso, Shana P C; Santos, Ana Clara V; Alves, Nathalia S; Couceiro, José Nelson S S; Gomes, Andre M O; Santos, Patricia S; Silva, Jerson L; Oliveira, Andréa C

    2017-04-06

    Avian influenza A viruses can cross naturally into mammals and cause severe diseases, as observed for H5N1. The high lethality of human infections causes major concerns about the real risk of a possible pandemic of severe diseases to which human susceptibility may be high and universal. High hydrostatic pressure (HHP) is a valuable tool for studies regarding the folding of proteins and the assembly of macromolecular structures such as viruses; furthermore, HHP has already been demonstrated to promote viral inactivation. Here, we investigated the structural stability of avian and human influenza viruses using spectroscopic and light-scattering techniques. We found that both particles have similar structural stabilities and that HHP promotes structural changes. HHP induced slight structural changes to both human and avian influenza viruses, and these changes were largely reversible when the pressure returned to its initial level. The spectroscopic data showed that H3N2 was more pressure-sensitive than H3N8. Structural changes did not predict changes in protein function, as H3N2 fusion activity was not affected, while H3N8 fusion activity drastically decreased. The fusion activity of H1N1 was also strongly affected by HHP. In all cases, HHP caused inactivation of the different influenza viruses. HHP may be a useful tool for vaccine development, as it induces minor and reversible structural changes that may be associated with partial preservation of viral biological activities and may potentiate their immunogenic response while abolishing their infectivity. We also confirmed that, although pressure does not promote drastic changes in viral particle structure, it can distinctly affect viral fusion activity. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Agreement of high definition oscillometry with direct arterial blood pressure measurement at different blood pressure ranges in horses under general anaesthesia.

    Science.gov (United States)

    Tünsmeyer, Julia; Hopster, Klaus; Feige, Karsten; Kästner, Sabine Br

    2015-05-01

    To determine the agreement of high definition oscillometry (HDO) with direct arterial blood pressure measurements in normotensive, hypotensive and hypertensive horses during general anaesthesia. Experimental study. Seven healthy warmblood horses, aged 3-11 years, weighing 470-565 kg. Measurements from a HDO device with the cuff placed around the base of the tail were compared with pressures measured invasively from the facial artery. High blood pressures were induced by intravenous (IV) administration of dobutamine (5 μg kg(-1) minute(-1)) over ten minutes followed by norepinephrine (0.1 mg kg(-1) IV) and low pressures by increasing the inspired fraction of isoflurane and administration of nitroglycerine (0.05 mg kg(-1) IV). For analysis three pressure levels were determined: high (MAP>110 mmHg), normal (60 mmHginvasive and invasive measurements. A total of 245 paired measurements of systolic (SAP), mean (MAP) and diastolic (DAP) pressures were obtained. The HDO device underestimated blood pressure at hypertensive and normotensive levels and overestimated blood pressure at hypotensive levels. Best agreement was obtained for SAP and MAP within normotensive limits. At normotension, bias ± standard deviation for SAP, MAP and DAP were 0.1 ± 19.4 mmHg, 0.5 ± 14.0, 4.7 ± 15.6, respectively. At high pressure levels bias and SD were 26.1 ± 37.3 (SAP), 4.2 ± 19.4 (MAP), 1.5 ± 16.8 (DAP) and at low pressures -20.0 ± 20.9 (SAP), -11.4 ± 19.6 (MAP), -4.7 ± 20.1 (DAP), with HDO measurements at a MAP invasive arterial blood pressures was obtained with HDO at normotensive levels in horses. At high and low pressure ranges HDO was unreliable. Therefore, if haemodynamic instability is expected, invasive measurement remains preferable. © 2014 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesia and Analgesia.

  11. Influence of Different Patellofemoral Design Variations Based on Genesis II Total Knee Endoprosthesis on Patellofemoral Pressure and Kinematics.

    Science.gov (United States)

    Leichtle, Ulf G; Lange, Barbara; Herzog, Yvonne; Schnauffer, Peter; Leichtle, Carmen I; Wülker, Nikolaus; Lorenz, Andrea

    2017-01-01

    In total knee arthroplasty (TKA), patellofemoral groove design varies greatly and likely has a distinct influence on patellofemoral biomechanics. To analyse the selective influence, five patellofemoral design variations were developed based on Genesis II total knee endoprosthesis (original design, being completely flat, being laterally elevated, being medially elevated, and both sides elevated) and made from polyamide using rapid prototyping. Muscle-loaded knee flexion was simulated on 10 human knee specimens using a custom-made knee simulator, measuring the patellofemoral pressure distribution and tibiofemoral and patellofemoral kinematics. The measurements were carried out in the native knee as well as after TKA with the 5 design prototypes. The overall influence of the different designs on the patellofemoral kinematics was small, but we found detectable effects for mediolateral tilt (p < 0.05 for 35°-80° flexion) and translation of the patella (p < 0.045 for 20°-65° and 75°-90°), especially for the completely flat design. Considering patellofemoral pressures, major interindividual differences were seen between the designs, which, on average, largely cancelled each other out. These results suggest that the elevation of the lateral margin of the patellofemoral groove is essential for providing mediolateral guidance, but smooth contouring as with original Genesis II design seems to be sufficient. The pronounced interindividual differences identify a need for more patellofemoral design options in TKA.

  12. Sex differences in time trends of blood pressure among Swedish septuagenarians examined three decades apart: a longitudinal population study.

    Science.gov (United States)

    Joas, Erik; Guo, Xinxin; Kern, Silke; Östling, Svante; Skoog, Ingmar

    2017-07-01

    The aim of this study was to analyze the influence of birth cohort, sex and age on the trajectories of SBP and DBP in two birth cohorts of 70-year-olds, examined 3 decades apart and followed up at ages 75 and 79-80 years. Two population samples of 70-year-olds from Gothenburg, Sweden, were examined. The first, born in 1901-1902, was examined in 1971-1972 (n = 973). The second, born in 1930, was examined in 2000 (n = 509). Both samples were re-examined at ages 75 and 79-80 years. We found that SBP and DBP were considerably lower in septuagenarian men and women born 1930 compared with those born 1901-1902, also when adjusting for antihypertensive treatment in different ways. The decline was especially pronounced in women. Blood pressure was higher in women than in men in the 1970s, whereas there were no sex differences in the 2000s. The age-related decline in SBP started earlier and was more accentuated in those born in 1930 than in those born in 1901-1902. Blood pressure decreased, and the age-related decline in SBP started earlier in septuagenarians examined in the 2000s compared with those examined in the 1970s. The decrease was especially pronounced in women and diminished the sex differences. Antihypertensive treatment only partly explained our findings, suggesting that other mostly unknown factors played an important role.

  13. Burst pressure of phaseguide structures of different heights in all-polymer microfluidic channels

    DEFF Research Database (Denmark)

    Garbarino, Francesca; Kistrup, Kasper; Rizzi, Giovanni

    2017-01-01

    fabricated by injection moulding and sealed by ultrasonic welding. Channels with a height of 200 m and widths of 1 mm or 3 mm were investigated for five values of between 8 m and 82 m. Phaseguide structures without branches and with branches at angles = 45°, 60° and 75° were studied. All phaseguide...... spreading and overflow in microfluidic channels by use of phaseguide structures with different heights and it also provides a set of systematic experimental data to be compared with simulations/theory....

  14. A sound pressure field during the quenching of a steel specimen in different water solutions

    Directory of Open Access Journals (Sweden)

    J. Prezelj

    2011-01-01

    Full Text Available The purpose of controlling the quenching process of an orange-hot steel workpiece is to ensure its required surface hardness. A sound in a cooling liquid generated by the quenching process was experimentally analyzed. It contains sufficient information about the ongoing process for its quantification, and it can be used in real time. Traditionally, the quenching and the resultant hardening can be controlled by selecting different process parameters, like, for example the characteristics of the cooling liquid, the velocity of the cooling liquid flow, its temperature, the temperature of the work-piece, and many others. The possibility of controlling the quenching process by using acoustic cavitation is considered in this article.

  15. Comparative assessment of two agriculturally-influenced estuaries: Similar pressure, different response.

    Science.gov (United States)

    Lemley, Daniel A; Adams, Janine B; Taljaard, Susan

    2017-04-15

    This study compared the spatio-temporal dynamics in two agriculturally-influenced South African estuaries - Gamtoos and Sundays - to investigate how contrasting hydrological alterations influence physical, chemical and biological responses. With the Gamtoos Estuary experiencing regular high flow conditions, a key difference between the two systems is the propensity for natural flushing events to occur; a mechanism largely eliminated from the highly-regulated Sundays Catchment. Phytoplankton blooms (>20Chl-aμgl-1) were persistent and seasonal in the Sundays, inducing summer bottom-water hypoxia (550μgl-1) and recurrent nature of two harmful algal bloom (HAB) species. This study provides the first account of HAB persistence and seasonal hypoxia in a South African estuary, demonstrating the possible consequences of shifting an ecosystem into a new stable state. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Promoter analysis by saturation mutagenesis

    Directory of Open Access Journals (Sweden)

    Baliga Nitin

    2001-01-01

    Full Text Available Gene expression and regulation are mediated by DNA sequences, in most instances, directly upstream to the coding sequences by recruiting transcription factors, regulators, and a RNA polymerase in a spatially defined fashion. Few nucleotides within a promoter make contact with the bound proteins. The minimal set of nucleotides that can recruit a protein factor is called a cis-acting element. This article addresses a powerful mutagenesis strategy that can be employed to define cis-acting elements at a molecular level. Technical details including primer design, saturation mutagenesis, construction of promoter libraries, phenotypic analysis, data analysis, and interpretation are discussed.

  17. Semiconductor saturable absorbers for ultrafast terahertz signals

    OpenAIRE

    Hoffmann, Matthias C.; Turchinovich, Dmitry

    2010-01-01

    We demonstrate saturable absorber behavior of n-type semiconductors GaAs, GaP, and Ge in the terahertz THz frequency range at room temperature using nonlinear THz spectroscopy. The saturation mechanism is based on a decrease in electron conductivity of semiconductors at high electron momentum states, due to conduction band onparabolicity and scattering into satellite valleys in strong THz fields. Saturable absorber parameters, such as linear and nonsaturable transmission, and saturation fluen...

  18. Semiconductor saturable absorbers for ultrafast terahertz signals

    OpenAIRE

    Hoffmann, Matthias C.; Turchinovich, Dmitry

    2010-01-01

    We demonstrate saturable absorber behavior of n-type semiconductorsGaAs,GaP, and Ge in the terahertz (THz) frequency range at room temperature using nonlinear THz spectroscopy. The saturation mechanism is based on a decrease in electron conductivity of semiconductors at high electron momentum states, due to conduction band nonparabolicity and scattering into satellite valleys in strong THz fields. Saturable absorber parameters, such as linear and nonsaturable transmission, and saturation flue...

  19. Influence of different safety shoes on gait and plantar pressure: a standardized examination of workers in the automotive industry.

    Science.gov (United States)

    Ochsmann, Elke; Noll, Ulrike; Ellegast, Rolf; Hermanns, Ingo; Kraus, Thomas

    2016-09-30

    Working conditions, such as walking and standing on hard surfaces, can increase the development of musculoskeletal complaints. At the interface between flooring and musculoskeletal system, safety shoes may play an important role in the well-being of employees. The aim of this study was to evaluate the effects of different safety shoes on gait and plantar pressure distributions on industrial flooring. Twenty automotive workers were individually fitted out with three different pairs of safety shoes ( "normal" shoes, cushioned shoes, and midfoot bearing shoes). They walked at a given speed of 1.5 m/s. The CUELA measuring system and shoe insoles were used for gait analysis and plantar pressure measurements, respectively. Statistical analysis was conducted by ANOVA analysis for repeated measures. Walking with cushioned safety shoes or a midfoot bearing safety shoe led to a significant decrease of the average trunk inclination (pindustrial accident, but in addition, safety shoes could be a long-term preventive instrument for maintaining health of the employees' musculoskeletal system, as they are able to affect gait parameters. Further research needs to focus on safety shoes in working situations.

  20. The impact of different footwear characteristics, of a ballet flat pump, on centre of pressure progression and perceived comfort.

    Science.gov (United States)

    Branthwaite, Helen; Chockalingam, Nachiappan; Greenhalgh, Andrew; Chatzistergos, Panagiotis

    2014-09-01

    Uncomfortable shoes have been attributed to poor fit and the cause of foot pathologies. Assessing and evaluating comfort and fit have proven challenging due to the subjective nature. The aim of this paper is to investigate the relationship between footwear characteristics and perceived comfort. Twenty-seven females assessed three different styles of ballet pump shoe for comfort using a comfort scale whilst walking along a 20 m walkway. The physical characteristics of the shoes and the progression of centre of pressure during walking were assessed. There were significant physical differences between each style, square shoe being the shortest, widest and stiffest and round shoe having the least volume at the toe box. Centre of pressure progression angle was centralised to the longitudinal axis of the foot when wearing each of the three shoes compared to barefoot. Length, width and cantilever bending stiffness had no impact on perceived comfort. Wearing snug fitting flexible soled round ballet flat pump is perceived to be the most comfortable of the shoe shapes tested producing a faster more efficient gait. Further investigations are required to assess impact/fit and upper material on perceived comfort to aid consumers with painful feet in purchasing shoes. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Predation determines different selective pressure on pea aphid host races in a complex agricultural mosaic.

    Directory of Open Access Journals (Sweden)

    Adalbert Balog

    Full Text Available Field assessments were conducted to examine the interplay between host plant and predation in complex agricultural mosaic on pea aphid clover and alfalfa races. In one experiment, we examined the relative fitness on clover race (CR and alfalfa race (AR pea aphids on broad bean, red clover and alfalfa alone. But because clover is typically grown in a more complex agricultural mosaic with alfalfa and broad bean, a second experiment was conducted to assess the fitness consequences under predation in a more complex agricultural field setting that also included potential apparent competition with AR pea aphids. In a third experiment we tested for the effect of differential host race density on the fitness of the other host race mediated by a predator effect. CR pea aphids always had fitness losses when on broad bean (had lower fitness on broad bean relative to red clover and fitness benefits when on red clover (higher fitness on red clover relative to broad bean, whether or not in apparent competition with alfalfa race aphids on bean and alfalfa. AR suffered fitness loss on both alfalfa and bean in apparent competition with CR on clover. Therefore we can conclude that the predation rate between host races was highly asymmetrical. The complexity of the agricultural mosaic thus can influence prey selection by predators on different host plants. These may have evolutionary consequences through context dependent fitness benefits on particular host plants.

  2. Helium permeability of different structure pyrolytic carbon coatings on graphite prepared at low temperature and atmosphere pressure

    Energy Technology Data Exchange (ETDEWEB)

    Song, Jinliang, E-mail: jlsong1982@yeah.net [Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Zhao, Yanling [School of Materials Science and Engineering, University of Jinan, Jinan 250022 (China); Zhang, Wenting [Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); School of Materials Science and Engineering, University of Jinan, Jinan 250022 (China); He, Xiujie; Zhang, Dongsheng; He, Zhoutong; Gao, Yantao; Jin, Chan; Xia, Huihao; Wang, Jianqiang; Huai, Ping; Zhou, Xingtai [Key Laboratory of Nuclear Radiation and Nuclear Energy Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China)

    2016-01-15

    Low density isotropic pyrolytic carbon (IPyC) and high density anisotropic pyrolytic carbon (APyC) coatings have been prepared at low temperature and atmosphere pressure. Helium gas permeabilities of nuclear graphite coated with IPyC and APyC of different thickness are studied using a vacuum apparatus. Both the permeation rates of the treated graphite gradually decrease with the increasing thickness of the coatings. The IPyC and APyC coatings can reduce the gas permeability coefficient of the samples by three and five orders of magnitude, respectively. The permeability difference is related to the microscopic structure, i.e., pores, as confirmed by scanning electron microscopy, mercury injection and X-ray tomography experiments. The changes of the permeability owing to heat cycles are observed to be negligible.

  3. Assessment of the biomechanical properties of porcine cornea after UV cross-linking at different intraocular pressures

    Science.gov (United States)

    Li, Jiasong; Singh, Manmohan; Vantipalli, Srilatha; Han, Zhaolong; Liu, Chih-Hao; Twa, Michael D.; Larin, Kirill V.

    2015-03-01

    In this study we demonstrate the use of phase-stabilized swept-source optical coherence elastography (PhS-SSOCE) to assess the biomechanical properties of porcine corneas before and after collagen cross-linking (CXL) at different intraocular pressures by measuring the velocity of an air-pulse induced elastic wave and recovery process rate of an air-pulse induced deformation. Young's moduli were estimated by two different methods: the shear wave equation and a newly developed elasticity reconstruction model. The results show that the corneas became stiffer after the CXL treatment, as evidenced by the increased elastic wave velocity and recovery process rate and greater Young's modulus. This non-contact and noninvasive measurement technique utilizes minimal force for excitation (deformation less than 10 μm in amplitude) of the tissue. Thus, it can be potentially used to study the biomechanical properties of ocular and other delicate tissues.

  4. An explorative investigation of functional differences in plantar center of pressure of four foot types using sample entropy method.

    Science.gov (United States)

    Mei, Zhanyong; Ivanov, Kamen; Zhao, Guoru; Li, Huihui; Wang, Lei

    2017-04-01

    In the study of biomechanics of different foot types, temporal or spatial parameters derived from plantar pressure are often used. However, there is no comparative study of complexity and regularity of the center of pressure (CoP) during the stance phase among pes valgus, pes cavus, hallux valgus and normal foot. We aim to analyze whether CoP sample entropy characteristics differ among these four foot types. In our experiment participated 40 subjects with normal feet, 40 with pes cavus, 19 with pes valgus and 36 with hallux valgus. A Footscan® system was used to collect CoP data. We used sample entropy to quantify several parameters of the investigated four foot types. These are the displacement in medial-lateral (M/L) and anterior-posterior (A/P) directions, as well as the vertical ground reaction force of CoP during the stance phase. To fully examine the potential of the sample entropy method for quantification of CoP components, we provide results for two cases: calculating the sample entropy of normalized CoP components, as well as calculating it using the raw data of CoP components. We also explored what are the optimal values of parameters m (the matching length) and r (the tolerance range) when calculating the sample entropy of CoP data obtained during the stance phases. According to statistical results, some factors significantly influenced the sample entropy of CoP components. The sample entropies of non-normalized A/P values for the left foot, as well as for the right foot, were different between the normal foot and pes valgus, and between the normal foot and hallux valgus. The sample entropy of normalized M/L displacement of the right foot was different between the normal foot and pes cavus. The measured variable for A/P and M/L displacements could serve for the study of foot function.

  5. Média diária do déficit de pressão de saturação do vapor d'água do ar e sua influência na vapotranspiração de referência pelo modelo de penman-monteith (FAO 56 em Piracicaba - SP Daily average of the saturation-vapor-pressure deficit of the air and its influence upon the reference evapotranspiration by penman-monteith model (FAO56 in Piracicaba, SP, Brazil

    Directory of Open Access Journals (Sweden)

    Gustavo B. Lyra

    2004-08-01

    Full Text Available Utilizando-se como padrão as medidas lisimétricas de um gramado, avaliaram-se os resultados de estimativas de ETo obtidas com Dar_méd oriundos de 14 métodos para seu cálculo. Tais comparações permitiram separar os métodos de cálculo de Dar_méd em três grupos, ou seja: um grupo resultou sempre em superestimativa de ETo; em outro, a tendência foi de sempre subestimar, e no último a tendência foi de superestimar valores baixos (The results of the evapotranspiration obtained with the Dair_avg proceeding from 14 methods were evaluated, by using the lysimetric measures of a sward. These comparisons allowed to separate the Dar_avg calculating methods into three groups: a group always resulted into an overestimate ETo; in other one always tended to underestimating the ETo; and in the last tended to overestimating the low values (<4.5 mm day-1, while underestimating the high values of ETo. No significant statistical differences were observed (t test; p <0.05 in ETo as a function of the Dair_avg methods, when using the hourly average of the temperature and/or the air relative humidity in relation to those determined with the average of the maximum and minimum values of these elements. Among the methods proposed by paper FAO56, just the one using the average relative humidity to calculate the actual pressure (e a showed a satisfactory estimate. The best estimates of ETo were obtained with the Dair_avg methods using the average of the air temperature in the determination of the saturation pressure (e s and the average of the relative humidity for the actual pressure (e a. The use of saturation-vapor-pressure deficit of the air at a single time (from 9 or 10 a.m. local as a representative of Dair_avg showed to be a satisfactory alternative in estimating the ETo under the climatic conditions of Piracicaba, SP, Brazil.

  6. INTRAOCULAR PRESSURE, MEAN ARTERIAL BLOOD PRESSURE AND PUPILLARY DIAMETER IN RABBITS ( (Oryctolagus cuniculus SUBJECTED TO RETROBULBAR BLOCK WITH DIFFERENT ANESTHETIC PROTOCOLS

    Directory of Open Access Journals (Sweden)

    Renata Maria Monção da Silva

    2015-10-01

    Full Text Available The aim of this study was to evaluate four protocols of loco regional anesthesia for ophthalmic procedures that could provide safety and life support, in addition to maintain intraocular pressure stable, with eye centralization and eyelid akinesia. 20 New Zealand rabbits were used to perform local anesthesia by retrobulbar block with four protocols: 2% lidocaine with epinephrine, 2% lidocaine without epinephrine associated with tramadol, 1% ropivacaine and bupivacaine 0.5 %. Each animal received an anesthetic volume of 1 mL. All anesthetic protocols used promoted eyelid akinesia and centralization of the eye during the assessment period. The retrobulbar block with the proposed anesthetic protocols proved to be feasible and safe for the maintenance of intraocular pressure, invasive blood pressure and pupillary diameter and can be used in intraocular surgeries, respecting the time of action of each anesthetic. All protocols showed an excellent blockage action but bupivacaine promoted the highest pupil diameter compared to the other drugs tested.

  7. Survival in macaroni penguins and the relative importance of different drivers: individual traits, predation pressure and environmental variability.

    Science.gov (United States)

    Horswill, Catharine; Matthiopoulos, Jason; Green, Jonathan A; Meredith, Michael P; Forcada, Jaume; Peat, Helen; Preston, Mark; Trathan, Phil N; Ratcliffe, Norman

    2014-09-01

    Understanding the demographic response of free-living animal populations to different drivers is the first step towards reliable prediction of population trends. Penguins have exhibited dramatic declines in population size, and many studies have linked this to bottom-up processes altering the abundance of prey species. The effects of individual traits have been considered to a lesser extent, and top-down regulation through predation has been largely overlooked due to the difficulties in empirically measuring this at sea where it usually occurs. For 10 years (2003-2012), macaroni penguins (Eudyptes chrysolophus) were marked with subcutaneous electronic transponder tags and re-encountered using an automated gateway system fitted at the entrance to the colony. We used multistate mark-recapture modelling to identify the different drivers influencing survival rates and a sensitivity analysis to assess their relative importance across different life stages. Survival rates were low and variable during the fledging year (mean = 0·33), increasing to much higher levels from age 1 onwards (mean = 0·89). We show that survival of macaroni penguins is driven by a combination of individual quality, top-down predation pressure and bottom-up environmental forces. The relative importance of these covariates was age specific. During the fledging year, survival rates were most sensitive to top-down predation pressure, followed by individual fledging mass, and finally bottom-up environmental effects. In contrast, birds older than 1 year showed a similar response to bottom-up environmental effects and top-down predation pressure. We infer from our results that macaroni penguins will most likely be negatively impacted by an increase in the local population size of giant petrels. Furthermore, this population is, at least in the short term, likely to be positively influenced by local warming. More broadly, our results highlight the importance of considering multiple causal effects across

  8. The effect of posture in premature infants on the arterial oxygen saturation, fraction of inspired oxygen and abdominal distension

    Directory of Open Access Journals (Sweden)

    Farzaneh Balali

    2017-11-01

    Full Text Available Background: Putting infants in a posture that reduces oxygen requirement and the complications of the continuous positive airway pressure method is very important. This study aimed at examining the effect of the posture on the arterial oxygen saturation, fraction of inspired oxygen (FIO2 and abdominal distension in premature infants with the respiratory distress syndrome under nasal continuous positive airway pressure. Materials and Methods: In this clinical trial study, 41 premature infants were selected by the simple random sampling and one-group before-after design. The amounts of arterial oxygen saturation, FIO2 and abdominal distension in supine and prone positions were recorded in a data-collection form. Results: There was a significant difference between the mean FIO2 and between the mean abdominal circumference in the prone and supine positions (P=0.022, P<0.001, respectively. There was no significant difference in the mean of arterial oxygen saturation between the two positions (P=0.749. Conclusion: According to the results of the present study, the neonates’ abdominal distension and FIO2 decreased in the prone position. Thus, this supportive, free of charge and effective method can be recommended for these neonates.

  9. Variation in size frequency distribution of coral populations under different fishing pressures in two contrasting locations in the Indian Ocean.

    Science.gov (United States)

    Grimsditch, G; Pisapia, C; Huck, M; Karisa, J; Obura, D; Sweet, M

    2017-10-01

    This study aimed to assess how the size-frequency distributions of coral genera varied between reefs under different fishing pressures in two contrasting Indian Ocean locations (the Maldives and East Africa). Using generalized linear mixed models, we were able to demonstrate that complex interactions occurred between coral genera, coral size class and fishing pressure. In both locations, we found Acropora coral species to be more abundant in non-fished compared to fished sites (a pattern which was consistent for nearly all the assessed size classes). Coral genera classified as 'stress tolerant' showed a contrasting pattern i.e. were higher in abundance in fished compared to non-fished sites. Site specific variations were also observed. For example, Maldivian reefs exhibited a significantly higher abundance in all size classes of 'competitive' corals compared to East Africa. This possibly indicates that East African reefs have already been subjected to higher levels of stress and are therefore less suitable environments for 'competitive' corals. This study also highlights the potential structure and composition of reefs under future degradation scenarios, for example with a loss of Acropora corals and an increase in dominance of 'stress tolerant' and 'generalist' coral genera. Copyright © 2017. Published by Elsevier Ltd.

  10. Impact of different water activities (aw adjusted by solutes on high pressure high temperature inactivation of Bacillus amyloliquefaciens spores

    Directory of Open Access Journals (Sweden)

    Robert eSevenich

    2015-07-01

    Full Text Available Much research has been conducted to comprehend the mechanisms of high pressure (HP inactivation of spores in aqueous systems but for food model systems these information are scarce. In these systems spores can interact with ingredients which could lead to retarded inactivation, which can cause a problem for the sterilization process. The protective mechanism of a reduced a_W-value is still unclear. HP processing might prove valuable to overcome protective effects of solutes and achieve shorter process times for sterilization under HP. To gain insight into the underlying mechanisms five a_W-values (0.9, 0.92, 0.94, 0.96, 1 were adjusted with 2 different solutes (NaCl, sucrose. Solutions were inoculated with spores of Bacillus amyloliquefaciens and treated at 105,110°C and115°C at 600 MPa. A thermal inactivation was conducted at the same temperatures for a compraison with the high pressure data. The influence of high pressure high temperature treatment on the inactivation, the DPA-release and membrane constitution was assessed by plate count, HPLC and flow cytometry. The results show that during HP treatments sucrose and salt both have a protective effect, in which the influence of sucrose on the retarded inactivation is higher. The threshold aw, which is 0.94, here salt and sucrose have a significant influence on the inactivation. The comparison of thermal (105-115°C and high pressure and high temperature (600 MPa, 105-115°C treated samples showed that the time needed to achieve a 4-5 log inactivation can be reduced at 600 MPa.The release of dipicolinic acid (DPA is the rate limiting step of the inactivation and therefore monitoring the release is of great interest. The DPA-release is slowed is slowed down in high concentrated solutions (e.g. sucrose, salt in comparison to aw 1. Maybe as shown for vegetative microorganism the solutes can interact with membranes, e.g. inner spore membrane. FCM (flow cytometry measurement data show a similar

  11. Central venous oxygen saturation does not correlate with the venous oxygen saturation at the surgical site during abdominal surgery.

    Science.gov (United States)

    Weinrich, Malte; Scheingraber, Stefan; Stephan, Bernhard; Weiss, Christel; Kayser, Anna; Kopp, Berit; Schilling, Martin K

    2008-01-01

    Measurement of central venous oxygen saturation has become a surrogate parameter for fluid administration, blood transfusions and treatment with catecholamines in (early) goal directed therapy in the treatment of acute septic patients. These strategies are not easily transferred to the postoperative management of abdominal surgery due to the different conditions in surgical patients. A study population of 15 patients (8 females/7 males) underwent elective major abdominal surgery: 6 gastrectomies, 5 major liver resections and 4 lower anterior rectum resections. Surgery was performed for primary or secondary malignancy. The patients' age was 65.4+/-12.7 (mean+/-standard deviation, range 44-84, median 62) years. Blood samples were taken intraoperatively from indwelling central venous lines as well as from draining veins at the surgical site. Blood gas analyses to determine the oxygen saturations were performed immediately. All patients were operated in standardized general anesthesia including epidural analgesia and in a balanced volume status. Central venous oxygen saturations and oxygen saturations in blood from the draining veins of the surgical site showed a wide range with high intra- and interindividual differences intraoperatively. Overall, at most time points no correlation between the two oxygen saturations could be detected in three operation types. A significant correlation was only observed at one time point during liver resections. Our results show a lack of correlation between central venous oxygen saturations and oxygen saturations in the draining veins of the surgical site during major abdominal surgery. Measurement of central venous oxygen saturations does not seem to be a good surrogate for the local oxygen supply in the field of interest in major abdominal surgery even under standardized conditions.

  12. PLD-grown thin film saturable absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Tellkamp, Friedjof

    2012-11-01

    The subject of this thesis is the preparation and characterization of thin films made of oxidic dielectrics which may find their application as saturable absorber in passively Q-switched lasers. The solely process applied for fabrication of the thin films was the pulsed laser deposition (PLD) which stands out against other processes by its flexibility considering the composition of the systems to be investigated. Within the scope of this thesis the applied saturable absorbers can be divided into two fundamentally different kinds of functional principles: On the one hand, saturable absorption can be achieved by ions embedded in a host medium. Most commonly applied bulk crystals are certain garnets like YAG (Y{sub 3}Al{sub 5}O{sub 12}) or the spinel forsterite (Mg{sub 2}SiO{sub 4}), in each case with chromium as dopant. Either of these media was investigated in terms of their behavior as PLD-grown saturable absorber. Moreover, experiments with Mg{sub 2}GeO{sub 4}, Ca{sub 2}GeO{sub 4}, Sc{sub 2}O{sub 3}, and further garnets like YSAG or GSGG took place. The absorption coefficients of the grown films of Cr{sup 4+}:YAG were determined by spectroscopic investigations to be one to two orders of magnitude higher compared to commercially available saturable absorbers. For the first time, passive Q-switching of a Nd:YAG laser at 1064 nm with Cr{sup 4+}:YAG thin films could be realized as well as with Cr:Sc{sub 2}O{sub 3} thin films. On the other hand, the desirable effect of saturable absorption can also be generated by quantum well structures. For this purpose, several layer system like YAG/LuAG, Cu{sub 2}O/MgO, and ZnO/corumdum were investigated. It turned out that layer systems with indium oxide (In{sub 2}O{sub 3}) did not only grew in an excellent way but also showed up a behavior regarding their photo luminescence which cannot be explained by classical considerations. The observed luminescence at roughly 3 eV (410 nm) was assumed to be of excitonic nature and its

  13. The use of saturation in qualitative research.

    Science.gov (United States)

    Walker, Janiece L

    2012-01-01

    Understanding qualitative research is an important component of cardiovascular nurses' practice and allows them to understand the experiences, stories, and perceptions of patients with cardiovascular conditions. In understanding qualitative research methods, it is essential that the cardiovascular nurse understands the process of saturation within qualitative methods. Saturation is a tool used for ensuring that adequate and quality data are collected to support the study. Saturation is frequently reported in qualitative research and may be the gold standard. However, the use of saturation within methods has varied. Hence, the purpose of this column is to provide insight for the cardiovascular nurse regarding the use of saturation by reviewing the recommendations for which qualitative research methods it is appropriate to use and how to know when saturation is achieved. In understanding saturation, the cardiovascular nurse can be a better consumer of qualitative research.

  14. Association of Inter-Arm Systolic Blood Pressure Difference with Coronary Atherosclerotic Disease Burden Using Calcium Scoring.

    Science.gov (United States)

    Her, Ae Young; Cho, Kyoung Im; Garg, Scot; Kim, Yong Hoon; Shin, Eun Seok

    2017-09-01

    There are no sufficient data on the correlation between inter-arm blood pressure (BP) difference and coronary atherosclerosis found using coronary artery calcium score (CACS). We aimed to investigate if the increased difference in inter-arm BP is independently associated with severity of CACS. Patients who had ≥3 cardiovascular risk factors or an intermediate Framingham Risk Score (FRS; ≥10) were enrolled. Inter-arm BP difference was defined as the absolute difference in BP in both arms. Quantitative CACS was measured by using coronary computed tomography angiography with the scoring system. A total of 261 patients were included in this study. Age (r=0.256, parm systolic BP (SBP; r=0.172, p=0.005), mean of left arm SBP (r=0.190, p=0.002), inter-arm SBP difference (r=0.152, p=0.014), and the FRS (r=0.278, parm SBP difference (≥6 mm Hg) was significantly associated with CACS ≥300 [odds ratio (OR) 2.17, 95% confidence interval (CI) 1.12-4.22; p=0.022]. In multivariable analysis, the inter-arm SBP difference ≥6 mm Hg was also significantly associated with CACS ≥300 after adjusting for clinical risk factors (OR 2.34, 95 % CI 1.06-5.19; p=0.036). An increased inter-arm SBP difference (≥6 mm Hg) is associated with coronary atherosclerotic disease burden using CACS, and provides additional information for predicting severe coronary calcification, compared to models based on traditional risk factors.

  15. Análise de crescimento de girassol em Latossolo com diferentes níveis de saturação por bases no Cerrado Growth analysis of sunflower in a Cerrado Oxisol with different levels of basis saturation

    Directory of Open Access Journals (Sweden)

    Renato Fernando Amabile

    2003-02-01

    Full Text Available Com o objetivo de avaliar o comportamento de cinco cultivares de girassol em um Latossolo Vermelho argiloso, foram realizados quatro ensaios sob quatro níveis de saturação por bases (18%, 35%, 56% e 77% obtidos com aplicação de calcário dolomítico. Os dados semanais de crescimento foram ajustados pelas funções logística, Weibull de três parâmetros e a logística generalizada de quatro parâmetros empregando-se o procedimento NLIN do SAS, bem como os processos interativos do método DUD. A função logística forneceu os melhores ajustes aos dados de crescimento. As cultivares foram categorizadas de acordo com o porte das plantas e tendências de crescimento a partir da análise de agrupamentos (cluster analysis, usando o método das ligações completas e a métrica da distância euclidiana. Todas as cultivares tiveram o crescimento reduzido quando o nível de saturação de bases foi de 18%. A cultivar M734 apresentou bom desempenho no nível de 35% de saturação por bases. Nos demais casos, os melhores resultados foram obtidos nos níveis de saturação por bases entre 56% e 77%. As cultivares EMBRAPA 122 e M738 tiveram redução de crescimento quando a saturação foi elevada para 77%. 'EMBRAPA 122' apresentou maior crescimento inicial e menor altura ao final do ciclo vegetativo.In order to study the growth cycle of five sunflower cultivars, four experiments were carried out under four levels of basis saturation (18%, 35%, 56% and 77%, obtained with the application of dolomitic limestone in an acidic Red Latosol, clay texture (Tipic Haplusthox. Weekly growth data were fitted using the Logistic, three parameters Weibull and four parameters Generalized Logistic (a special case of Richards function functions. Among the models used, the Logistic function obtained was the best growth data fitting. The NLIN procedure of SAS statistical package was used for fitting the data through the interactive process of DUD method. Cultivars were

  16. Nitrogen saturation in humid tropical forests after 6 years of nitrogen and phosphorus addition

    DEFF Research Database (Denmark)

    Chen, Hao; Gurmesa, Geshere A.; Zhang, Wei

    2016-01-01

    Nitrogen (N) saturation hypothesis suggests that when an ecosystem reaches N-saturation, continued N input will cause increased N leaching, nitrous oxide (N2O) emission, and N mineralization and nitrification rates. It also suggests that a different element will become the main limiting......O emission rate and nitrate (NO3-) leaching rate were measured in an N-saturated old-growth tropical forest in southern China, after 6 years of N and P addition. We hypothesized that N addition would stimulate further N saturation, but P addition might alleviate N saturation. As expected, our...

  17. Prevalence and reproducibility of differences between home and ambulatory blood pressure and their relation with hypertensive organ damage.

    Science.gov (United States)

    Gazzola, K; Cammenga, M; van der Hoeven, N V; van Montfrans, G A; van den Born, B J H

    2017-09-01

    Home and ambulatory blood pressure (BP) better predict cardiovascular disease than office BP, but are not interchangeable. We hypothesised that home BP may be higher than office BP because of anticipatory reactions to self-measurement and studied prevalence and reproducibility of incremental differences between home and daytime ambulatory BP and their relation with hypertensive organ damage. A total of 176 participants (mean age 57.1±12.8 years, 43.2% female) measured their BP for 2 weeks and received a 24-h ambulatory BP in between. Hypertensive organ damage was assessed by urinary albumin-to-creatinine ratio and electrocardiographic criteria for left ventricular hypertrophy. Thresholds of 10/5 and 20/10 mm Hg were used to define relevant systolic/diastolic differences between home and ambulatory BP. A higher home compared to ambulatory BP was present in 92 (52.3%) and 35 (19.1%) participants, while lower home BP values were present in 36 (20.4%) and 8 (4.5%) subjects for differences ⩾10/5 and ⩾20/10 mm Hg. Participants with higher home than ambulatory BP differences were older, had higher body mass index, higher office BP, more antihypertensive medication and lower glomerular filtration rate (Phome and ambulatory BP were highly reproducible (r=0.80 and 0.67 for systolic and diastolic BP, Phome and ambulatory BPs were associated with organ damage, but their difference was not. Many patients have a significantly higher home than ambulatory BP. Differences between home and ambulatory BP are reproducible, but not associated with hypertensive organ damage. Our findings suggest that ambulatory BP remains the standard of reference when positive differences between home and ambulatory BP exist.

  18. Differing prognostic value of pulse pressure in patients with heart failure with reduced or preserved ejection fraction

    DEFF Research Database (Denmark)

    Jackson, Colette E; Castagno, Davide; Maggioni, Aldo P

    2015-01-01

    AIMS: Low pulse pressure is a marker of adverse outcome in patients with heart failure (HF) and reduced ejection fraction (HF-REF) but the prognostic value of pulse pressure in patients with HF and preserved ejection fraction (HF-PEF) is unknown. We examined the prognostic value of pulse pressure......) and 5008 with HF-PEF (828 deaths). Pulse pressure was analysed in quintiles in a multivariable model adjusted for the previously reported Meta-Analysis Global Group in Chronic Heart Failure prognostic variables. Heart failure and reduced ejection fraction patients in the lowest pulse pressure quintile had...

  19. Cerebral regional oxygen saturation monitoring in pediatric malfunctioning shunt patients.

    Science.gov (United States)

    Abramo, Thomas J; Zhou, Chuan; Estrada, Cristina; Drayna, Patrick C; Locklair, Matthew R; Miller, Renee; Pearson, Matthew; Tulipan, Noel; Arnold, Donald H

    2013-02-01

    Shunt malfunction produces increased intracranial pressure causing decreased cerebral regional perfusion and tissue O(2)sat. Cerebral regional oxygen saturation (rSO(2)) by near-infrared spectroscopy represents tissue perfusion and oxygen saturation. Cerebral rSO(2) is used to detect cerebral ischemia in pediatric clinical settings. The objective of the study was to determine the reliability of cerebral rSO(2) in pediatric malfunctioning shunt. A prospective observational study of pediatric patients presented to the pediatric emergency department was conducted. Confirmed malfunctioning shunt subjects had cerebral rSO(2) monitoring. A total of 131 malfunctioning shunt subjects had cerebral rSO(2) monitoring. Patient's central trend and intrasubject variability of cerebral rSO(2) readings for left and right probe and malfunction sites (n = 131) are as follows: Intrasubject left and right rSO(2) Pearson correlation was -0.46 to 0.98 (mean ± SD, 0.35 ± 0.34; median, 0.34; interquartile range, 0.06-0.61). The correlation coefficients of 99 subjects between left and right rSO(2) was significantly different (P < .001), suggesting that intrasubjects' left and right rSO(2) are highly correlated. Sample mean difference between left and right rSO(2) were -1.7% (95% confidence interval [CI], -1.8 to -1.6; P < .001) supporting overall left lower than right. Intraclass correlation for left rSO(2) was 87.4% (95% CI, 87.2%-87.6%), and that for right rSO(2) was 83.8% (95% CI, 83.8%-84%), showing intersubject differences accounting for the variation, and relative to intersubject variation, intrasubjects readings are consistent. Intrasubjects, left and right rSO(2) highly correlate and are asymmetrical. Left and right rSO(2) are consistent in intrasubject with large rSO(2) variations in trend and variability across subjects. This study demonstrates reliable cerebral rSO(2) readings in subjects with malfunctioning shunts, with asymmetrical cerebral rSO(2) hemispheric dynamics within

  20. An improved film evaporation correlation for saline water at sub-atmospheric pressures

    KAUST Repository

    Shahzada, Muhammad Wakil

    2011-10-03

    This paper presents an investigation of heat transfer correlation in a falling-film evaporator working with saline water at sub-atmospheric pressures. The experiments are conducted at different salinity levels ranging from 15000 to 90000 ppm, and the pressures were maintained between 0.92 to 2.81 kPa (corresponds to saturation temperatures of 5.9 – 23 0C). The effect of salinity, saturation pressures and chilled water temperatures on the heat transfer coefficient are accounted in the modified film evaporation correlations. The results are fitted to the Han & Fletcher\\'s and Chun & Seban\\'s falling-film correlations which are used in desalination industry. We modify the said correlations by adding salinity and saturation temperature corrections with respective indices to give a better agreement to our measured data.

  1. An improved film evaporation correlation for saline water at sub-atmospheric pressures

    Science.gov (United States)

    Shahzada, Muhammad Wakil; Ng, Kim Choon; Thu, Kyaw; Myat, Aung; Gee, Chun Won

    2012-06-01

    This paper presents an investigation of heat transfer correlation in a falling-film evaporator working with saline water at sub-atmospheric pressures. The experiments are conducted at different salinity levels ranging from 15000 to 90000 ppm, and the pressures were maintained between 0.92 to 2.81 kPa (corresponds to saturation temperatures of 5.9 - 23 0C). The effect of salinity, saturation pressures and chilled water temperatures on the heat transfer coefficient are accounted in the modified film evaporation correlations. The results are fitted to the Han & Fletcher's and Chun & Seban's falling-film correlations which are used in desalination industry. We modify the said correlations by adding salinity and saturation temperature corrections with respective indices to give a better agreement to our measured data.

  2. Phase field modeling of partially saturated deformable porous media

    Science.gov (United States)

    Sciarra, Giulio

    2016-09-01

    A poromechanical model of partially saturated deformable porous media is proposed based on a phase field approach at modeling the behavior of the mixture of liquid water and wet air, which saturates the pore space, the phase field being the saturation (ratio). While the standard retention curve is expected still^ to provide the intrinsic retention properties of the porous skeleton, depending on the porous texture, an enhanced description of surface tension between the wetting (liquid water) and the non-wetting (wet air) fluid, occupying the pore space, is stated considering a regularization of the phase field model based on an additional contribution to the overall free energy depending on the saturation gradient. The aim is to provide a more refined description of surface tension interactions. An enhanced constitutive relation for the capillary pressure is established together with a suitable generalization of Darcy's law, in which the gradient of the capillary pressure is replaced by the gradient of the so-called generalized chemical potential, which also accounts for the "force", associated to the local free energy of the phase field model. A micro-scale heuristic interpretation of the novel constitutive law of capillary pressure is proposed, in order to compare the envisaged model with that one endowed with the concept of average interfacial area. The considered poromechanical model is formulated within the framework of strain gradient theory in order to account for possible effects, at laboratory scale, of the micro-scale hydro-mechanical couplings between highly localized flows (fingering) and localized deformations of the skeleton (fracturing).

  3. INTRAOCULAR PRESSURE, MEAN ARTERIAL BLOOD PRESSURE AND PUPILLARY DIAMETER IN RABBITS ( (Oryctolagus cuniculus) ) SUBJECTED TO RETROBULBAR BLOCK WITH DIFFERENT ANESTHETIC PROTOCOLS

    OpenAIRE

    Renata Maria Monção da Silva; Francisco de Assis Dórea Neto; Vivian Fernanda Barbosa; Newton Nunes; Emanoel Ferreira Martins Filho; Arianne Pontes Oria

    2015-01-01

    The aim of this study was to evaluate four protocols of loco regional anesthesia for ophthalmic procedures that could provide safety and life support, in addition to maintain intraocular pressure stable, with eye centralization and eyelid akinesia. 20 New Zealand rabbits were used to perform local anesthesia by retrobulbar block with four protocols: 2% lidocaine with epinephrine, 2% lidocaine without epinephrine associated with tramadol, 1% ropivacaine and bupivacaine 0.5 %. Each animal recei...

  4. High pressure processing and post-high pressure storage induce the change of polyglutamyl folate and total folate from different legumes.

    Science.gov (United States)

    Luo, Shuangyan; Duan, Hanying; Zou, Yuchen; Wang, Chao

    2017-10-01

    The aim of this wor