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Sample records for surface dilatational modulus

  1. Dilational surface rheology of polymer solutions

    International Nuclear Information System (INIS)

    Noskov, B A; Bykov, A G

    2015-01-01

    The review concerns main achievements in dilational rheology of polymer adsorption films at the gas/liquid interfaces reported in the last fifteen years. The theoretical foundations of methods of surface rheology and the key results obtained in studies of solutions of amphiphilic nonionic polymers, polyelectrolytes, proteins and their complexes with low-molecular-mass surfactants are discussed. Interest in the surface dilational rheology is mainly caused by a small number of available experimental methods for investigation of the surface of liquids, by the fact that traditional methods of measurement of the surface tension that are widely used in studies of solutions of low-molecular-mass surfactants provide little information when applied to polymer solutions owing to very slow establishment of equilibrium as well as by weak dependence of the surface tension on the polymer concentration. Progress in the surface rheology is driven by the recent studies of the stability of foams and emulsions that demonstrated a key role of the dilational surface rheological properties in the dynamics of liquid-phase disperse systems. The bibliography includes 191 references

  2. Generalized surface momentum balances for the analysis of surface dilatational data

    NARCIS (Netherlands)

    Sagis, L.M.C.

    2013-01-01

    Dilatational rheological properties of interfaces are often determined using drop tensiometers, in which the interface of the droplet is subjected to oscillatory area changes. A dynamic surface tension is determined either by image analysis of the droplet profile or by measuring the capillary

  3. The pore-load modulus of ordered nanoporous materials with surface effects

    Science.gov (United States)

    Liu, Mingchao; Wu, Jian; Gan, Yixiang; Chen, C. Q.

    2016-03-01

    Gas and liquid adsorption-induced deformation of ordered porous materials is an important physical phenomenon with a wide range of applications. In general, the deformation can be characterized by the pore-load modulus and, when the pore size reduces to nanoscale, it is affected by surface effects and shows prominent size-dependent features. In this Letter, the influence of surface effects on the elastic properties of ordered nanoporous materials with internal pressure is accounted for in a single pore model. A porosity and surface elastic constants dependent closed form solution for the size dependent pore-load modulus is obtained and verified by finite element simulations and available experimental results. In addition, it is found to depend on the geometrical arrangement of pores. This study provides an efficient tool to analyze the surface effects on the elastic response of ordered nanoporous materials.

  4. Influence of heat treatment and veneering on the storage modulus and surface of zirconia ceramic.

    Science.gov (United States)

    Siavikis, Georgius; Behr, Michael; van der Zel, Jef M; Feilzer, Albert J; Rosentritt, Martin

    2011-04-01

    Glass-ceramic veneered zirconia is used for the application as fixed partial dentures. The aim of this investigation was to evaluate whether the heat treatment during veneering, the application of glass-ceramic for veneering or long term storage has an influence on the storage modulus of zirconia. Zirconia bars (Cercon, DeguDent, G; 0.5x2x20 mm) were fabricated and treated according to veneering conditions. Besides heating regimes between 680°C and 1000°C (liner bake and annealing), sandblasting (Al(2)O(3)) or steam cleaning were used. The bars were investigated after 90 days storage in water and acid. For investigating the influence of veneering, the bars were veneered in press- or layer technique. Dynamic mechanical analysis (DMA) in a three-point-bending design was performed to determine the storage modulus between 25°C and 200°C at a frequency of 1.66 Hz. All specimens were loaded on top and bottom (treatment on pressure or tensile stress side). Scanning electron microscopy (SEM) was used for evaluating the superficial changes of the zirconia surface due to treatment. Statistical analysis was performed using Mann Whitney U-test (α=0.05). Sintered zirconia provided a storage modulus E' of 215 (203/219) GPa and tan δ of 0.04 at 110°C. A 10%-decrease of E' was found up to 180°C. The superficial appearance changed due to heating regime. Sandblasting reduced E' to 213 GPa, heating influenced E' between 205 GPa (liner bake 1) and 222 GPa (dentin bake 1). Steam cleaning, annealing and storage changed E' between 4 GPa and 22 GPa, depending on the side of loading. After veneering, strong E'-reduction was found down to 84 GPa and 125 GPa. Veneering of zirconia with glass-ceramic in contrast to heat treating during veneering procedure had a strong influence on the modulus. The application of the glass-ceramic caused a stronger decrease of the storage modulus.

  5. Design of the Elastic Modulus of Nanoparticles-Containing PVA/PVAc Films by the Response Surface Method

    Science.gov (United States)

    Jelinska, N.; Kalnins, M.; Kovalovs, A.; Chate, A.

    2015-11-01

    By the surface response method, a regression equation is constructed, and the tensile elastic modulus of films made from polyvinyl alcohol/polyvinyl acetate (PVA/PVAc) blends filled with montmorillonite clay and microcrystalline cellulose nanoparticles is investigated. It is established that the introduction of the nanoparticles improves the mechanical properties of the blends in tension considerably: their strength and elastic modulus increase with content of the particles. Using the regression equation, the optimum composition of nanoparticlefilled PVA/PVAc blends with the highest value of elastic modulus is found.

  6. Linear and nonlinear modulus surfaces in stress space, from stress-strain measurements on Berea sandstone

    Directory of Open Access Journals (Sweden)

    M. Boudjema

    2003-01-01

    Full Text Available The elastic response of many rocks to quasistatic stress changes is highly nonlinear and hysteretic, displaying discrete memory. Rocks also display unusual nonlinear response to dynamic stress changes. A model to describe the elastic behavior of rocks and other consolidated materials is called the Preisach-Mayergoyz (PM space model. In contrast to the traditional analytic approach to stress-strain, the PM space picture establishes a relationship between the quasistatic data and a number density of hysteretic mesoscopic elastic elements in the rock. The number density allows us to make quantitative predictions of dynamic elastic properties. Using the PM space model, we analyze a complex suite of quasistatic stress-strain data taken on Berea sandstone. We predict a dynamic bulk modulus and a dynamic shear modulus surface as a function of mean stress and shear stress. Our predictions for the dynamic moduli compare favorably to moduli derived from time of flight measurements. We derive a set of nonlinear elastic constants and a set of constants that describe the hysteretic behavior of the sandstone.

  7. Protein conformational transitions at the liquid-gas interface as studied by dilational surface rheology.

    Science.gov (United States)

    Noskov, Boris A

    2014-04-01

    Experimental results on the dynamic dilational surface elasticity of protein solutions are analyzed and compared. Short reviews of the protein behavior at the liquid-gas interface and the dilational surface rheology precede the main sections of this work. The kinetic dependencies of the surface elasticity differ strongly for the solutions of globular and non-globular proteins. In the latter case these dependencies are similar to those for solutions of non-ionic amphiphilic polymers and have local maxima corresponding to the formation of the distal region of the surface layer (type I). In the former case the dynamic surface elasticity is much higher (>60 mN/m) and the kinetic dependencies are monotonical and similar to the data for aqueous dispersions of solid nanoparticles (type II). The addition of strong denaturants to solutions of bovine serum albumin and β-lactoglobulin results in an abrupt transition from the type II to type I dependencies if the denaturant concentration exceeds a certain critical value. These results give a strong argument in favor of the preservation of the protein globular structure in the course of adsorption without any denaturants. The addition of cationic surfactants also can lead to the non-monotonical kinetic dependencies of the dynamic surface elasticity indicating destruction of the protein tertiary and secondary structures. The addition of anionic surfactants gives similar results only for the protein solutions of high ionic strength. The influence of cationic surfactants on the local maxima of the kinetic dependencies of the dynamic surface elasticity for solutions of a non-globular protein (β-casein) differs from the influence of anionic surfactants due to the heterogeneity of the charge distribution along the protein chain. In this case one can use small admixtures of ionic surfactants as probes of the adsorption mechanism. The effect of polyelectrolytes on the kinetic dependencies of the dynamic surface elasticity of protein

  8. Size-dependent Young’s modulus in ZnO nanowires with strong surface atomic bonds

    Science.gov (United States)

    Fan, Shiwen; Bi, Sheng; Li, Qikun; Guo, Qinglei; Liu, Junshan; Ouyang, Zhongliang; Jiang, Chengming; Song, Jinhui

    2018-03-01

    The mechanical properties of size-dependent nanowires are important in nano-electro-mechanical systems (NEMSs), and have attracted much research interest. Characterization of the size effect of nanowires in atmosphere directly to broaden their practical application instead of just in high vacuum situations, as reported previously, is desperately needed. In this study, we systematically studied the Young’s modulus of vertical ZnO nanowires in atmosphere. The diameters ranged from 48 nm to 239 nm with a resonance method using non-contact atomic force microscopy. The values of Young’s modulus in atmosphere present extremely strong increasing tendency with decreasing diameter of nanowire due to stronger surface atomic bonds compared with that in vacuum. A core-shell model for nanowires is proposed to explore the Young’s modulus enhancement in atmosphere, which is correlated with atoms of oxygen occurring near the nanowire surface. The modified model is more accurate for analyzing the mechanical behavior of nanowires in atmosphere compared with the model in vacuum. Furthermore, it is possible to use this characterization method to measure the size-related elastic properties of similar wire-sharp nanomaterials in atmosphere and estimate the corresponding mechanical behavior. The study of the size-dependent Young’s modulus in ZnO nanowires in atmosphere will improve the understanding of the mechanical properties of nanomaterials as well as providing guidance for applications in NEMSs, nanogenerators, biosensors and other related areas.

  9. Anisotropic surface strain in single crystalline cobalt nanowires and its impact on the diameter-dependent Young's modulus

    KAUST Repository

    Huang, Xiaohu

    2013-01-01

    Understanding and measuring the size-dependent surface strain of nanowires are essential to their applications in various emerging devices. Here, we report on the diameter-dependent surface strain and Young\\'s modulus of single-crystalline Co nanowires investigated by in situ X-ray diffraction measurements. Diameter-dependent initial longitudinal elongation of the nanowires is observed and ascribed to the anisotropic surface stress due to the Poisson effect, which serves as the basis for mechanical measurements. As the nanowire diameter decreases, a transition from the "smaller is softer" regime to the "smaller is tougher" regime is observed in the Young\\'s modulus of the nanowires, which is attributed to the competition between the elongation softening and the surface stiffening effects. Our work demonstrates a new nondestructive method capable of measuring the initial surface strain and estimating the Young\\'s modulus of single crystalline nanowires, and provides new insights on the size effect. © 2013 The Royal Society of Chemistry.

  10. Influence of heat treatment and veneering on the storage modulus and surface of zirconia ceramic

    NARCIS (Netherlands)

    Siavikis, G.; Behr, M.; van der Zel, J.M.; Feilzer, A.J.; Rosentritt, M.

    2011-01-01

    Objectives: Glass-ceramic veneered zirconia is used for the application as fixed partial dentures. The aim of this investigation was to evaluate whether the heat treatment during veneering, the application of glass-ceramic for veneering or long term storage has an influence on the storage modulus of

  11. Interfacial layers from the protein HFBII hydrophobin: dynamic surface tension, dilatational elasticity and relaxation times.

    Science.gov (United States)

    Alexandrov, Nikola A; Marinova, Krastanka G; Gurkov, Theodor D; Danov, Krassimir D; Kralchevsky, Peter A; Stoyanov, Simeon D; Blijdenstein, Theodorus B J; Arnaudov, Luben N; Pelan, Eddie G; Lips, Alex

    2012-06-15

    The pendant-drop method (with drop-shape analysis) and Langmuir trough are applied to investigate the characteristic relaxation times and elasticity of interfacial layers from the protein HFBII hydrophobin. Such layers undergo a transition from fluid to elastic solid films. The transition is detected as an increase in the error of the fit of the pendant-drop profile by means of the Laplace equation of capillarity. The relaxation of surface tension after interfacial expansion follows an exponential-decay law, which indicates adsorption kinetics under barrier control. The experimental data for the relaxation time suggest that the adsorption rate is determined by the balance of two opposing factors: (i) the barrier to detachment of protein molecules from bulk aggregates and (ii) the attraction of the detached molecules by the adsorption layer due to the hydrophobic surface force. The hydrophobic attraction can explain why a greater surface coverage leads to a faster adsorption. The relaxation of surface tension after interfacial compression follows a different, square-root law. Such behavior can be attributed to surface diffusion of adsorbed protein molecules that are condensing at the periphery of interfacial protein aggregates. The surface dilatational elasticity, E, is determined in experiments on quick expansion or compression of the interfacial protein layers. At lower surface pressures (<11 mN/m) the experiments on expansion, compression and oscillations give close values of E that are increasing with the rise of surface pressure. At higher surface pressures, E exhibits the opposite tendency and the data are scattered. The latter behavior can be explained with a two-dimensional condensation of adsorbed protein molecules at the higher surface pressures. The results could be important for the understanding and control of dynamic processes in foams and emulsions stabilized by hydrophobins, as well as for the modification of solid surfaces by adsorption of such

  12. Direct Measurements of Surface Energy, Elastic Modulus and Interparticle Forces of Titan Aerosol Analog (`Tholin') Using Atomic Force Microscopy

    Science.gov (United States)

    Yu, X.; Horst, S. M.; He, C.; McGuiggan, P.; Bridges, N. T.

    2017-12-01

    To understand the origin of the dunes on Titan, it is important to investigate the material properties of the sand particles on Titan, which are mainly made of organics deposited from the atmosphere [1]. The organic sand may behave differently compared to the quartz/basaltic sand on terrestrial planets (Earth, Venus, Mars) in terms of interparticle forces. We measured the surface energy (through contact angle measurements) and elastic modulus (through Atomic Force Microscopy, AFM) of Titan aerosol analog (tholins) produced in our lab. Tholins may be compositionally similar to sand on Titan. We directly measured the interparticle forces between a tholin particle adhered to an AFM cantilver and tholin particles on a substrate. We also measured the properties of walnut shells, a typical material used in the Titan Wind Tunnel (TWT, [2, 3]). We find the surface energy of a tholin thin film is about 70.9 mN/m and its elastic modulus is about 3.5 GPa (similar to hard polymers like PMMA and polystyrene). We used the two measured material properties of tholin to calculate its interparticle cohesion assuming simple sphere-sphere geometry [4]. For two 20 µm particles, the theoretical cohesion force is about 6682 nN. Under dry nitrogen (RHmeasured interparticle forces using AFM was approximately 4000 nN, which is smaller than theoretical predictions but still relatively strong under dry conditions. The interparticle cohesion between walnut shell particles is only 200 nN, which is much lower than between tholin particles. The key finding of this study is that the interparticle cohesion forces are much larger for tholins and presumably Titan sand particles than for terrestrial sand and materials used in the wind tunnel. This suggests we should increase the interparticle force in both analog experiments (TWT) and threshold models (e.g. [5]) to correctly translate the results to real Titan conditions. The strong cohesion of tholins may also inform us how the small aerosol

  13. Two component silicone modified epoxy foul release coatings: Effect of modulus, surface energy and surface restructuring on pseudobarnacle and macrofouling behavior

    International Nuclear Information System (INIS)

    Rath, S.K.; Chavan, J.G.; Sasane, Savita; Jagannath; Patri, M.; Samui, A.B.; Chakraborty, B.C.

    2010-01-01

    Two component silicone modified epoxy resin based low surface energy and non-toxic foul release coatings were developed. Silicone modified epoxy resin with 15 and 30% silicone content was used as component A and a polyether diamine (Jeffamine-500) was used as the component B. Free standing films were prepared by casting a mixture of components A and B in stoichiometric proportions. The surface composition, surface topography and wetting properties of the coatings were studied by angle resolved X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and contact angle goniometry respectively. The mechanical properties of the cured films were evaluated by tensile measurements as well as dynamic mechanical analysis. Pseudobarnacles made of aluminium studs were attached to the coated panels and adhesion tests were carried out by a pseudobarnacle tester. Coated panels were exposed in Mumbai harbor for fouling studies for a period of 90 days. Surface restructuring studies of the coatings upon immersion in seawater were carried out by measuring the changes in advancing and receding contact angles by contact angle goniometry. The effect of surface energy, modulus and surface restructuring of the coatings on the macrofouling and pseudobarnacle adhesion properties has been discussed in detail.

  14. Nonlinear Surface Dilatational Rheology and Foaming Behavior of Protein and Protein Fibrillar Aggregates in the Presence of Natural Surfactant.

    Science.gov (United States)

    Wan, Zhili; Yang, Xiaoquan; Sagis, Leonard M C

    2016-04-19

    The surface and foaming properties of native soy glycinin (11S) and its heat-induced fibrillar aggregates, in the presence of natural surfactant steviol glycoside (STE), were investigated and compared at pH 7.0 to determine the impact of protein structure modification on protein-surfactant interfacial interactions. The adsorption at, and nonlinear dilatational rheological behavior of, the air-water interface were studied by combining drop shape analysis tensiometry, ellipsometry, and large-amplitude oscillatory dilatational rheology. Lissajous plots of surface pressure versus deformation were used to analyze the surface rheological response in terms of interfacial microstructure. The heat treatment generates a mixture of long fibrils and unconverted peptides. The presence of small peptides in 11S fibril samples resulted in a faster adsorption kinetics than that of native 11S. The addition of STE affected the adsorption of 11S significantly, whereas no apparent effect on the adsorption of the 11S fibril-peptide system was observed. The rheological response of interfaces stabilized by 11S-STE mixtures also differed significantly from the response for 11S fibril-peptide-STE mixtures. For 11S, the STE reduces the degree of strain hardening in extension and increases strain hardening in compression, suggesting the interfacial structure may change from a surface gel to a mixed phase of protein patches and STE domains. The foams generated from the mixtures displayed comparable foam stability to that of pure 11S. For 11S fibril-peptide mixtures STE only significantly affects the response in extension, where the degree of strain softening is decreased compared to the pure fibril-peptide system. The foam stability of the fibril-peptide system was significantly reduced by STE. These findings indicate that fibrillization of globular proteins could be a potential strategy to modify the complex surface and foaming behaviors of protein-surfactant mixtures.

  15. Inverting Comet Acoustic Surface Sounding Experiment (CASSE) touchdown signals to measure the elastic modulus of comet material

    Science.gov (United States)

    Arnold, W.; Faber, C.; Knapmeyer, M.; Witte, L.; Schröder, S.; Tune, J.; Möhlmann, D.; Roll, R.; Chares, B.; Fischer, H.; Seidensticker, K.

    2014-07-01

    The landing of Philae on comet 67P/Churyumov-Gerasimenko is scheduled for November 11, 2014. Each of the three landing feet of Philae house a triaxial acceleration sensor of CASSE, which will thus be the first sensors to be in mechanical contact with the cometary surface. CASSE will be in listening mode to record the deceleration of the lander, when it impacts with the comet at a velocity of approx. 0.5 m/s. The analysis of this data yields information on the reduced elastic modulus and the yield stress of the comet's surface material. We describe a series of controlled landings of a lander model. The tests were conducted in the Landing & Mobility Test Facility (LAMA) of the DLR Institute of Space Systems in Bremen, Germany, where an industrial robot can be programmed to move landers or rovers along predefined paths, allowing to adapt landing procedures with predefined velocities. The qualification model of the Philae landing gear was used in the tests. It consists of three legs manufactured of carbon fiber and metal joints. A dead mass of the size and mass of the lander housing is attached via a damper above the landing gear to represent the lander structure as a whole. Attached to each leg is a foot with two soles and a mechanically driven fixation screw (''ice screw'') to secure the lander on the comet. The right soles, if viewed from the outside towards the lander body, house a Brüel & Kjaer DeltaTron 4506 triaxial piezoelectric accelerometer as used on the spacecraft. Orientation of the three axes was such that one of the axes, here the X-axis of the accelerometer, points downwards, while the Y- and Z-axes are horizontal. Data were recorded at a sampling rate of 8.2 kHz within a time gate of 2 s. In parallel, a video sequence was taken, in order to monitor the touchdown on the sand and the movement of the ice screws. Touchdown measurements were conducted on three types of ground with landing velocities between 0.1 to 1.1 m/s. Landings with low velocities were

  16. An Integrated Laser-Induced Piezoelectric/Differential Confocal Surface Acoustic Wave System for Measurement of Thin Film Young’s Modulus

    Directory of Open Access Journals (Sweden)

    Xiaotang Hu

    2012-09-01

    Full Text Available The present paper presents the design and development results of a system setup for measuring Young’s modulus of thin films by laser-induced surface acoustic waves based on the integration of two detection methods, namely, piezoelectric transducer detection and differential confocal detection, which may be used for conducting consecutive or simultaneous measurements. After demonstrating the capabilities of each detection approach, it is shown how, depending on a wider range of applications, sample materials and measurement environments, the developed integrated system inherits and harnesses the main characteristics of its detection channels, resulting in an more practical and flexible equipment for determining Young’s modulus than traditional nanoindentation equipment, and also suitable for cross-validation purposes.

  17. Paschke Dilations

    Directory of Open Access Journals (Sweden)

    Abraham Westerbaan

    2017-01-01

    Full Text Available In 1973 Paschke defined a factorization for completely positive maps between C*-algebras. In this paper we show that for normal maps between von Neumann algebras, this factorization has a universal property, and coincides with Stinespring's dilation for normal maps into B(H.

  18. Dilated cardiomyopathy

    International Nuclear Information System (INIS)

    Salvatore, M.; Cuocolo, A.

    1988-01-01

    Radionuclide techniques are easily obtainable, noninvasive examinations that provide useful information in the evaluation, diagnosis and management of patients with dilated cardiomyopathy. The gated blood pool scan allows the assessment of ventricular size, configuration, and wall and septal thickness. These data allow the functional class of the cardiomyopathy (congestive, restrictive or hypertrophic) to be defined. Often THallium-201 myocardial perfusion imaging adds further information and is particularly useful in distinguishing congestive cardiomyopathy from severe coronary artery disease and in depicting septal abnormalities in hipertrophic cardiomyopathy. Useful as these techniques are, they are not substitutes for conventional approaches to diagnosis. Careful history taking and physical examination, as well as scrutiny of the electrocardiogram, chest X-ray and echocardiogram should be standard practice for the evaluation of patients with suspected cardiomyopathy. Judicious use of noninvasive techniques may obviate the need for cardiac catheterization in many patients

  19. Dilating Eye Drops

    Science.gov (United States)

    ... Frequently Asked Questions Español Condiciones Chinese Conditions Dilating Eye Drops En Español Read in Chinese What are dilating eye drops? Dilating eye drops contain medication to enlarge ( ...

  20. Competitive adsorption from mixed hen egg-white lysozyme/surfactant solutions at the air-water interface studied by tensiometry, ellipsometry, and surface dilational rheology.

    Science.gov (United States)

    Alahverdjieva, V S; Grigoriev, D O; Fainerman, V B; Aksenenko, E V; Miller, R; Möhwald, H

    2008-02-21

    The competitive adsorption at the air-water interface from mixed adsorption layers of hen egg-white lysozyme with a non-ionic surfactant (C10DMPO) was studied and compared to the mixture with an ionic surfactant (SDS) using bubble and drop shape analysis tensiometry, ellipsometry, and surface dilational rheology. The set of equilibrium and kinetic data of the mixed solutions is described by a thermodynamic model developed recently. The theoretical description of the mixed system is based on the model parameters for the individual components.

  1. Monomer conversion, dimensional stability, strength, modulus, surface apatite precipitation and wear of novel, reactive calcium phosphate and polylysine-containing dental composites.

    Directory of Open Access Journals (Sweden)

    Kanokrat Kangwankai

    Full Text Available The aim was to assess monomer conversion, dimensional stability, flexural strength / modulus, surface apatite precipitation and wear of mono / tri calcium phosphate (CaP and polylysine (PLS-containing dental composites. These were formulated using a new, high molecular weight, fluid monomer phase that requires no polymerisation activator.Urethane and Polypropylene Glycol Dimethacrylates were combined with low levels of an adhesion promoting monomer and a light activated initiator. This liquid was mixed with a hybrid glass containing either 10 wt% CaP and 1 wt% PLS (F1 or 20 wt% CaP and 2 wt% PLS (F2. Powder to liquid mass ratio was 5:1. Commercial controls included Gradia Direct Posterior (GD and Filtek Z250 (FZ. Monomer conversion and polymerisation shrinkage were calculated using Fourier Transform Infrared (FTIR. Subsequent volume increases in water over 7 weeks were determined using gravimetric studies. Biaxial flexural strength (BFS / modulus (BFM reduction and surface apatite precipitation upon 1 and 4 weeks immersion in water versus simulated body fluid (SBF were assessed using a mechanical testing frame and scanning electron microscope (SEM. Mass / volume loss and surface roughness (Ra following 7 weeks water immersion and subsequent accelerated tooth-brush abrasion were examined using gravimetric studies and profilometer.F1 and F2 exhibited much higher monomer conversion (72% than FZ (54% and low calculated polymerization shrinkage (2.2 vol%. Final hygroscopic expansions decreased in the order; F2 (3.5 vol% > F1 (1.8 vol% ~ Z250 (1.6 vol% > Gradia (1.0 vol%. BFS and BFM were unaffected by storage medium type. Average BFS / BFM upon 4 weeks immersion reduced from 144 MPa / 8 GPa to 107 MPa / 5 GPa for F1 and 105 MPa / 6 GPa to 82 MPa / 4 GPa for F2. Much of this change was observed in the first week of immersion when water sorption rate was high. Surface apatite layers were incomplete at 1 week, but around 2 and 15 micron thick for F1 and

  2. Experimental Young's modulus calculations

    International Nuclear Information System (INIS)

    Chen, Y.; Jayakumar, R.; Yu, K.

    1994-01-01

    Coil is a very important magnet component. The turn location and the coil size impact both mechanical and magnetic behavior of the magnet. The Young's modulus plays a significant role in determining the coil location and size. Therefore, Young's modulus study is essential in predicting both the analytical and practical magnet behavior. To determine the coil Young's modulus, an experiment has been conducted to measure azimuthal sizes of a half quadrant QSE101 inner coil under different loading. All measurements are made at four different positions along an 8-inch long inner coil. Each measurement is repeated three times to determine the reproducibility of the experiment. To ensure the reliability of this experiment, the same measurement is performed twice with a open-quotes dummy coil,close quotes which is made of G10 and has the same dimension and similar azimuthal Young's modulus as the inner coil. The difference between the G10 azimuthal Young's modulus calculated from the experiments and its known value from the manufacturer will be compared. Much effort has been extended in analyzing the experimental data to obtain a more reliable Young's modulus. Analysis methods include the error analysis method and the least square method

  3. Accurate in situ measurement of near-surface volume dilatation in irradiated silica through capacitance monitoring of cantilever deflection

    International Nuclear Information System (INIS)

    Norris, C.B.; EerNisse, E.P.

    1983-01-01

    Irradiating a solid with short-range particle often induces a net volume change in the range zone which results in a shallow layer of stressed material. Micron-depth volume dilatations in the part-per-million range can be studied using cantilever mounting of a long, thin, metallized specimen, whose stress-induced bending perturbs the capacitance between the cantilever and a small counterelectrode mounted close to the unirradiated face. This approach has been used successfully by many workers for more than 20 yrs. Elsewhere we have reported the construction of a highly sensitive caltilever/capacitor apparatus and its application in the first accurate measurements of ionization dilatation phenomena in fused silica and grown SiO 2 at low-electron energies. In this paper we outline key details of apparatus design and experimental technique for successful cantilever/capacitor work. Many contrasts with the work of Primak and Monahan [Rev. Sci. Instrum. 54, 544 (1983) (preceding paper)] are pointed out. We also highlight previous short-term annealing results which make it clear that the compaction of silica will appear to be significantly less in optical measurements made hours after irradiation than in our cantilever/capacitor measurements made minutes after irradiation

  4. Influence of substrate modulus on gecko adhesion

    Science.gov (United States)

    Klittich, Mena R.; Wilson, Michael C.; Bernard, Craig; Rodrigo, Rochelle M.; Keith, Austin J.; Niewiarowski, Peter H.; Dhinojwala, Ali

    2017-03-01

    The gecko adhesion system fascinates biologists and materials scientists alike for its strong, reversible, glue-free, dry adhesion. Understanding the adhesion system’s performance on various surfaces can give clues as to gecko behaviour, as well as towards designing synthetic adhesive mimics. Geckos encounter a variety of surfaces in their natural habitats; tropical geckos, such as Gekko gecko, encounter hard, rough tree trunks as well as soft, flexible leaves. While gecko adhesion on hard surfaces has been extensively studied, little work has been done on soft surfaces. Here, we investigate for the first time the influence of macroscale and nanoscale substrate modulus on whole animal adhesion on two different substrates (cellulose acetate and polydimethylsiloxane) in air and find that across 5 orders of magnitude in macroscale modulus, there is no change in adhesion. On the nanoscale, however, gecko adhesion is shown to depend on substrate modulus. This suggests that low surface-layer modulus may inhibit the gecko adhesion system, independent of other influencing factors such as macroscale composite modulus and surface energy. Understanding the limits of gecko adhesion is vital for clarifying adhesive mechanisms and in the design of synthetic adhesives for soft substrates (including for biomedical applications and wearable electronics).

  5. Pnematic Dilation in Achalasia

    Directory of Open Access Journals (Sweden)

    Maximilian Bittinger

    2001-01-01

    Full Text Available Pneumatic dilation is the most common first-line therapy for the treatment of achalasia. The aim of dilation is a controlled disruption of circular muscle fibres of the lower esophageal sphincter to reduce the functional obstruction. Several types of dilators and different dilation techniques are used, but the achieved results are similar. The mean success rate is about 80% in the short term, but some patients need redilation in the further course (particularly young patients. Best long term results are obtained if the lower esophageal sphincter pressure can be reduced below 10 mmHg. Major complications are rare after pneumatic dilation; the most serious complication is esophageal perforation, which occurs at a mean rate of about 2.5%. Considering the pros and cons of other effective forms of treatment of achalasia (esophagomyotomy and intrasphincteric injection of botulinum toxin, pneumatic dilation is still the treatment of choice in the majority of patients with achalasia.

  6. High-temperature Young’s moduli and dilatation behavior of silica refractories

    Czech Academy of Sciences Publication Activity Database

    Pabst, W.; Gregorová, E.; Kloužek, Jaroslav; Kloužková, A.; Zemenová, P.; Kohoutková, M.; Sedlářová, I.; Lang, K.; Kotouček, M.; Nevřivová, L.; Všianský, D.

    2016-01-01

    Roč. 36, č. 1 (2016), s. 209-220 ISSN 0955-2219 Institutional support: RVO:67985891 Keywords : silica refractories * Young’s modulus * elastic modulus * dilatation * dilatometry Subject RIV: JH - Ceramic s, Fire-Resistant Materials and Glass Impact factor: 3.411, year: 2016

  7. Percutaneous dilatational tracheostomy

    DEFF Research Database (Denmark)

    Johnsen, R.

    2015-01-01

    Introduction Since the introduction and development of percutaneous dilatational tracheostomy (PDT), this procedure is accepted and incorporated in ICUs worldwide. In spite of obvious benefits for the patients, who obtain more comfort and mobility and less use of sedatives, the procedure also...... providers' notes are entered. When searching for -percutaneous dilatation tracheostomy' in the electronic system, we found all patients who had undergone this specific procedure. Afterwards we analyzed each of these patients' hospital records, looking for any periprocedure or postprocedure complications...

  8. Low elastic modulus Ti–Ta alloys for load-bearing permanent implants: Enhancing the biodegradation resistance by electrochemical surface engineering

    Energy Technology Data Exchange (ETDEWEB)

    Kesteven, Jazmin [Biomaterials and Engineering Materials (BEM) Laboratory, School of Engineering and Physical Sciences, James Cook University, Townsville, Queensland 4811 (Australia); Kannan, M. Bobby, E-mail: bobby.mathan@jcu.edu.au [Biomaterials and Engineering Materials (BEM) Laboratory, School of Engineering and Physical Sciences, James Cook University, Townsville, Queensland 4811 (Australia); Walter, Rhys; Khakbaz, Hadis [Biomaterials and Engineering Materials (BEM) Laboratory, School of Engineering and Physical Sciences, James Cook University, Townsville, Queensland 4811 (Australia); Choe, Han-Choel [Department of Dental Materials, Chosun University, Gwangju 501-759 (Korea, Republic of)

    2015-01-01

    In this study, the in vitro degradation behaviour of titanium–tantalum (Ti–Ta) alloys (10–30 wt.% Ta) was investigated and compared with conventional implant materials, i.e., commercially pure titanium (Cp-Ti) and titanium–aluminium–vanadium (Ti6Al4V) alloy. Among the three Ti–Ta alloys studied, the Ti20Ta (6.3 × 10{sup −4} mm/y) exhibited the lowest degradation rate, followed by Ti30Ta (1.2 × 10{sup −3} mm/y) and Ti10Ta (1.4 × 10{sup −3} mm/y). All the Ti–Ta alloys exhibited lower degradation rate than that of Cp-Ti (1.8 × 10{sup −3} mm/y), which suggests that Ta addition to Ti is beneficial. As compared to Ti6Al4V alloy (8.1 × 10{sup −4} mm/y), the degradation rate of Ti20Ta alloy was lower by ∼ 22%. However, the Ti30Ta alloy, which has closer elastic modulus to that of natural bone, showed ∼ 48% higher degradation rate than that of Ti6Al4V alloy. Hence, to improve the degradation performance of Ti30Ta alloy, an intermediate thin porous layer was formed electrochemically on the alloy followed by calcium phosphate (CaP) electrodeposition. The coated Ti30Ta alloy (3.8 × 10{sup −3} mm/y) showed ∼ 53% lower degradation rate than that of Ti6Al4V alloy. Thus, the study suggests that CaP coated Ti30Ta alloy can be a viable material for load-bearing permanent implants. - Highlights: • In vitro degradation of titanium–tantalum (Ti–Ta) alloys was studied. • Ta addition to Ti is beneficial for better degradation resistance. • Ti–Ta alloys perform better than commercially pure Ti. • Calcium phosphate coated Ti–Ta alloy is superior to Ti6Al4V alloy.

  9. Impairment of flow-mediated dilation correlates with aortic dilation in patients with Marfan syndrome.

    Science.gov (United States)

    Takata, Munenori; Amiya, Eisuke; Watanabe, Masafumi; Omori, Kazuko; Imai, Yasushi; Fujita, Daishi; Nishimura, Hiroshi; Kato, Masayoshi; Morota, Tetsuro; Nawata, Kan; Ozeki, Atsuko; Watanabe, Aya; Kawarasaki, Shuichi; Hosoya, Yumiko; Nakao, Tomoko; Maemura, Koji; Nagai, Ryozo; Hirata, Yasunobu; Komuro, Issei

    2014-07-01

    Marfan syndrome is an inherited disorder characterized by genetic abnormality of microfibrillar connective tissue proteins. Endothelial dysfunction is thought to cause aortic dilation in subjects with a bicuspid aortic valve; however, the role of endothelial dysfunction and endothelial damaging factors has not been elucidated in Marfan syndrome. Flow-mediated dilation, a noninvasive measurement of endothelial function, was evaluated in 39 patients with Marfan syndrome. Aortic diameter was measured at the aortic annulus, aortic root at the sinus of Valsalva, sinotubular junction and ascending aorta by echocardiography, and adjusted for body surface area (BSA). The mean value of flow-mediated dilation was 6.5 ± 2.4 %. Flow-mediated dilation had a negative correlation with the diameter of the ascending thoracic aorta (AscAd)/BSA (R = -0.39, p = 0.020) and multivariate analysis revealed that flow-mediated dilation was an independent factor predicting AscAd/BSA, whereas other segments of the aorta had no association. Furthermore, Brinkman index had a somewhat greater influence on flow-mediated dilation (R = -0.42, p = 0.008). Although subjects who smoked tended to have a larger AscAd compared with non-smokers (AscA/BSA: 17.3 ± 1.8 versus 15.2 ± 3.0 mm/m(2), p = 0.013), there was no significant change in flow-mediated dilation, suggesting that smoking might affect aortic dilation via an independent pathway. Common atherogenic risks, such as impairment of flow-mediated dilation and smoking status, affected aortic dilation in subjects with Marfan syndrome.

  10. Standard test method for Young's modulus, tangent modulus, and chord modulus

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2004-01-01

    1.1 This test method covers the determination of Young's modulus, tangent modulus, and chord modulus of structural materials. This test method is limited to materials in which and to temperatures and stresses at which creep is negligible compared to the strain produced immediately upon loading and to elastic behavior. 1.2 Because of experimental problems associated with the establishment of the origin of the stress-strain curve described in 8.1, the determination of the initial tangent modulus (that is, the slope of the stress-strain curve at the origin) and the secant modulus are outside the scope of this test method. 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory require...

  11. Influence of the Testing Gage Length on the Strength, Young's Modulus and Weibull Modulus of Carbon Fibres and Glass Fibres

    Directory of Open Access Journals (Sweden)

    Luiz Claudio Pardini

    2002-10-01

    Full Text Available Carbon fibres and glass fibres are reinforcements for advanced composites and the fiber strength is the most influential factor on the strength of the composites. They are essentially brittle and fail with very little reduction in cross section. Composites made with these fibres are characterized by a high strength/density ratio and their properties are intrisically related to their microstructure, i.e., amount and orientation of the fibres, surface treatment, among other factors. Processing parameters have an important role in the fibre mechanical behaviour (strength and modulus. Cracks, voids and impurities in the case of glass fibres and fibrillar misalignments in the case of carbon fibres are created during processing. Such inhomogeneities give rise to an appreciable scatter in properties. The most used statistical tool that deals with this characteristic variability in properties is the Weibull distribution. The present work investigates the influence of the testing gage length on the strength, Young's modulus and Weibull modulus of carbon fibres and glass fibres. The Young's modulus is calculated by two methods: (i ASTM D 3379M, and (ii interaction between testing equipment/specimen The first method resulted in a Young modulus of 183 GPa for carbon fibre, and 76 GPa for glass fibre. The second method gave a Young modulus of 250 GPa for carbon fibre and 50 GPa for glass fibre. These differences revelead differences on how the interaction specimen/testing machine can interfere in the Young modulus calculations. Weibull modulus can be a tool to evaluate the fibre's homogeneity in terms of properties and it is a good quality control parameter during processing. In the range of specimen gage length tested the Weibull modulus for carbon fibre is ~ 3.30 and for glass fibres is ~ 5.65, which indicates that for the batch of fibres tested, the glass fibre is more uniform in properties.

  12. Fluid dynamics of dilatant fluid

    DEFF Research Database (Denmark)

    Nakanishi, Hiizu; Nagahiro, Shin-ichiro; Mitarai, Namiko

    2012-01-01

    A dense mixture of granules and liquid often shows a severe shear thickening and is called a dilatant fluid. We construct a fluid dynamics model for the dilatant fluid by introducing a phenomenological state variable for a local state of dispersed particles. With simple assumptions for an equation...

  13. Roentgenoendovascular dilatation of brachycephalic arteries

    International Nuclear Information System (INIS)

    Rabkin, I.Kh.; Kachel, R.; Glazer, F.; Matevosov, A.L.; Dzhoraev, I.G.; Medizinische Akademie, Erfurt

    1988-01-01

    The authors reported the technique, methods of and indications for roentgenoendovascular dilation in stenotic and occlusive lesions of the brachycephalic branches of the aorta. A total of 102 vascular dilations were perfomed in 76 patients resulting in a good angiographic and clinical effect. In 2 patients the first world prosthetics was performed using an original coiled nitinol prosthesis

  14. Plastic cap evolution law derived from induced transverse isotropy in dilatational triaxial compression.

    Energy Technology Data Exchange (ETDEWEB)

    Macon, David James [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brannon, Rebecca Moss [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Strack, Otto Eric [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-02-01

    Mechanical testing of porous materials generates physical data that contain contributions from more than one underlying physical phenomenon. All that is measurable is the "ensemble" hardening modulus. This thesis is concerned with the phenomenon of dilatation in triaxial compression of porous media, which has been modeled very accurately in the literature for monotonic loading using models that predict dilatation under triaxial compression (TXC) by presuming that dilatation causes the cap to move outwards. These existing models, however, predict a counter-intuitive (and never validated) increase in hydrostatic compression strength. This work explores an alternative approach for modeling TXC dilatation based on allowing induced elastic anisotropy (which makes the material both less stiff and less strong in the lateral direction) with no increase in hydrostatic strength. Induced elastic anisotropy is introduced through the use of a distortion operator. This operator is a fourth-order tensor consisting of a combination of the undeformed stiffness and deformed compliance and has the same eigenprojectors as the elastic compliance. In the undeformed state, the distortion operator is equal to the fourth-order identity. Through the use of the distortion operator, an evolved stress tensor is introduced. When the evolved stress tensor is substituted into an isotropic yield function, a new anisotropic yield function results. In the case of the von Mises isotropic yield function (which contains only deviatoric components), it is shown that the distortion operator introduces a dilatational contribution without requiring an increase in hydrostatic strength. In the thesis, an introduction and literature review of the cap function is given. A transversely isotropic compliance is presented, based on a linear combination of natural bases constructed about a transverse-symmetry axis. Using a probabilistic distribution of cracks constructed for the case of transverse isotropy, a

  15. Segmental dilatation of the ileum

    Directory of Open Access Journals (Sweden)

    Tune-Yie Shih

    2017-01-01

    Full Text Available A 2-year-old boy was sent to the emergency department with the chief problem of abdominal pain for 1 day. He was just discharged from the pediatric ward with the diagnosis of mycoplasmal pneumonia and paralytic ileus. After initial examinations and radiographic investigations, midgut volvulus was impressed. An emergency laparotomy was performed. Segmental dilatation of the ileum with volvulus was found. The operative procedure was resection of the dilated ileal segment with anastomosis. The postoperative recovery was uneventful. The unique abnormality of gastrointestinal tract – segmental dilatation of the ileum, is described in details and the literature is reviewed.

  16. Vessel dilatation in coronary angiograms

    Energy Technology Data Exchange (ETDEWEB)

    Hinterauer, L.; Goebel, N.

    1983-11-01

    Amongst 166 patients with aneurysms, ectasia or megaloarteries shown on coronary angiograms, 86.1% had dilated vessels as part of generalised coronary sclerosis (usually in patients with three-vessel disease). In 9%, dilatation was of iatrogenic origin and in 4.8% it was idiopathic. One patient had Marfan's syndrome. Amongst 9 000 patients, there were eight with megalo-arteries without stenosis; six of these had atypical angina and three suffered an infarct. Patients with definite dilatation of the coronary artery and stagnation of contrast flow required treatment.

  17. Vessel dilatation in coronary angiograms

    International Nuclear Information System (INIS)

    Hinterauer, L.; Goebel, N.

    1983-01-01

    Amongst 166 patients with aneurysms, ectasia or megaloarteries shown on coronary angiograms, 86.1% had dilated vessels as part of generalised coronary sclerosis (usually in patients with three-vessel disease). In 9%, dilatation was of iatrogenic origin and in 4.8% it was idiopathic. One patient had Marfan's syndrome. Amongst 9 000 patients, there were eight with megalo-arteries without stenosis; six of these had atypical angina and three suffered an infarct. Patients with definite dilatation of the coronary artery and stagnation of contrast flow required treatment. (orig.) [de

  18. Dilatancy in Slow Granular Flows

    Science.gov (United States)

    Kabla, Alexandre J.; Senden, Tim J.

    2009-06-01

    When walking on wet sand, each footstep leaves behind a temporarily dry impression. This counterintuitive observation is the most common illustration of the Reynolds principle of dilatancy: that is, a granular packing tends to expand as it is deformed, therefore increasing the amount of porous space. Although widely called upon in areas such as soil mechanics and geotechnics, a deeper understanding of this principle is constrained by the lack of analytical tools to study this behavior. Using x-ray radiography, we track a broad variety of granular flow profiles and quantify their intrinsic dilatancy behavior. These measurements frame Reynolds dilatancy as a kinematic process. Closer inspection demonstrates, however, the practical importance of flow induced compaction which competes with dilatancy, leading more complex flow properties than expected.

  19. The effect of physiological conditions on the surface structure of proteins: Setting the scene for human digestion of emulsions

    Science.gov (United States)

    Maldonado-Valderrama, J.; Gunning, A. P.; Ridout, M. J.; Wilde, P. J.; Morris, V. J.

    2009-10-01

    Understanding and manipulating the interfacial mechanisms that control human digestion of food emulsions is a crucial step towards improved control of dietary intake. This article reports initial studies on the effects of the physiological conditions within the stomach on the properties of the film formed by the milk protein ( β -lactoglobulin) at the air-water interface. Atomic force microscopy (AFM), surface tension and surface rheology techniques were used to visualize and examine the effect of gastric conditions on the network structure. The effects of changes in temperature, pH and ionic strength on a pre-formed interfacial structure were characterized in order to simulate the actual digestion process. Changes in ionic strength had little effect on the surface properties. In isolation, acidification reduced both the dilatational and the surface shear modulus, mainly due to strong repulsive electrostatic interactions within the surface layer and raising the temperature to body temperature accelerated the rearrangements within the surface layer, resulting in a decrease of the dilatational response and an increase of surface pressure. Together pH and temperature display an unexpected synergism, independent of the ionic strength. Thus, exposure of a pre-formed interfacial β -lactoglobulin film to simulated gastric conditions reduced the surface dilatational modulus and surface shear moduli. This is attributed to a weakening of the surface network in which the surface rearrangements of the protein prior to exposure to gastric conditions might play a crucial role.

  20. Brain Abscess after Esophageal Dilatation

    DEFF Research Database (Denmark)

    Gaïni, S; Grand, M; Michelsen, J

    2007-01-01

    with malaise, progressive lethargy, fever, aphasia and hemiparesis. Six days before she had been treated with esophageal dilatation for a stricture caused by accidental ingestion of caustic soda. The brain abscess was treated with surgery and antibiotics. She recovered completely. This clinical case...

  1. Compressive modulus of adhesive bonded rubber block

    OpenAIRE

    Wiriya Thongruang; Charoenyut Dechwayukul

    2008-01-01

    The present study examined the effect of a thin adhesive layer on the modulus of an elastic rubber block bonded between two plates. The plates were assumed to be rigid, both in extension and flexure, and subjected to vertical compression loading. The Gent’s approach was used to obtain the analytic deformations of the rubber and adhesive. The analytic deformations were then validated with the finite element model. There was a good agreement between both methods. The modulus of the bonded rubbe...

  2. Compressive modulus of adhesive bonded rubber block

    Directory of Open Access Journals (Sweden)

    Wiriya Thongruang

    2008-03-01

    Full Text Available The present study examined the effect of a thin adhesive layer on the modulus of an elastic rubber block bonded between two plates. The plates were assumed to be rigid, both in extension and flexure, and subjected to vertical compression loading. The Gent’s approach was used to obtain the analytic deformations of the rubber and adhesive. The analytic deformations were then validated with the finite element model. There was a good agreement between both methods. The modulus of the bonded rubber block, defined as effective modulus, was then studied. The effective modulus was increased by the factor (1+ (a/2t2(6Grh/Gat+1-1, which is composed of the shape factor of the rubber block (a/2t, ratio of the bonded and unbonded areas, and the shear stiffness factor (Grh/Gat, ratio of modulus and thickness of rubber and adhesive. The effective modulus does not depend on either factors, when the shear stiffness of the joint is high or Grh/Gat >10.

  3. Oversampling of wavelet frames for real dilations

    DEFF Research Database (Denmark)

    Bownik, Marcin; Lemvig, Jakob

    2012-01-01

    We generalize the Second Oversampling Theorem for wavelet frames and dual wavelet frames from the setting of integer dilations to real dilations. We also study the relationship between dilation matrix oversampling of semi-orthogonal Parseval wavelet frames and the additional shift invariance gain...

  4. Balloon dilatation of iatrogenic urethral strictures

    International Nuclear Information System (INIS)

    Acunas, B.; Acunas, G.; Gokmen, E.; Celik, L.

    1988-01-01

    Balloon dilatation of the urethra was performed in five patients with iatrogenic urethral strictures. The urethral strictures were successfully negotiated and dilated in all patients. Redilatation became necessary in a period ranging from 3 to 10 months. The authors believe that balloon dilatation of the urethra can be safely and successfully performed; the procedure produces minimal trauma and immediate relief of symptoms. (orig.)

  5. Effect of enzymatic hydrolysis on surface activity and surface rheology of type I collagen.

    Science.gov (United States)

    Kezwoń, Aleksandra; Chromińska, Ilona; Frączyk, Tomasz; Wojciechowski, Kamil

    2016-01-01

    We describe the adsorption behaviour and rheological properties of a calf skin type I collagen, and of its hydrolysates obtained using a Clostridium histolyticum collagenase (CHC) under moderate conditions (pH 7, 37°C). The effect of CHC concentration (2×10(-9)-2×10(-6)M) and incubation time (35-85min) was studied and optimised to achieve the highest decrease of surface tension and the highest dilational surface viscoelasticity of the adsorbed layers. SDS-PAGE electrophoresis and reverse-phase high performance liquid chromatography (RP-HPLC) were used to characterise the hydrolysis products. The results show that even simple modifications (heat treatment, pH change, partial hydrolysis) of collagen enhances its surface properties, especially in terms of surface dilational elasticity modulus. The use of low enzyme concentration (CHC-to-collagen molar ratio of 4×10(-3)) and short incubation time (<45min) results in moderately hydrolysed products with the highest ability to lower surface tension (γ=53.9mNm(-1)) forming highly elastic adsorbed layers (surface dilational elasticity, E'=74.5mNm(-1)). Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Balloon dilatations of esophageal strictures

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Jeong Jin; Juhng, Seon Kwan; Kim, Jae Kyu; Chung, Hyon De [Chonnam National University College of Medicine, Seoul (Korea, Republic of)

    1990-04-15

    Most benign esophageal strictures can be successfully dilated with conventional bougienage technique. But occasionally strictures are so tight, lengthy, or sometimes irregular that this technique fail, and surgical intervention is required. Since 1974 Gruentzig balloon catheter has succeed when used for strictures in the cardiac and peripheral vasculatures, the biliary and urinary tracts, the colon of neonates after inflammatory disease and also in the esophagus. Fluoroscopically guided balloon catheters were used to dilate 30 esophageal strictures in 30 patients over 3 years at Department of Diagnostic Radiology, Chonnam University, College of Medicine. The distribution of age was from 7 years to 71 days and the ratio of male to female was 15:15. The causes of benign stricture (23 cases) were post-operative strictures (13), chemical (4), achalasia (3), chronic inflammation (2), esophageal rupture (1) and those of malignant stricture (7 cases) were post-radiation stricture of primary esophageal cancer (6) and metastatic esophageal cancer (1). The success rate of procedure was 93% (28/30). The causes of failure were the failure of passage of stricture due to markedly dilated proximal segment of esophagus (1 case) and too long segment of stricture (1 case). Complication of procedure was the diverticular-formation of esophagus in 3 cases, but has no clinical significance in follow-up esophagography. In conclusion, fluoroscopically guided balloon dilation of esophageal stricture appears to be safe, effective treatment and may be have theoretical advantages over conventional bougienage and also should be considered before other methods of treatment are used.

  7. Balloon dilatations of esophageal strictures

    International Nuclear Information System (INIS)

    Seo, Jeong Jin; Juhng, Seon Kwan; Kim, Jae Kyu; Chung, Hyon De

    1990-01-01

    Most benign esophageal strictures can be successfully dilated with conventional bougienage technique. But occasionally strictures are so tight, lengthy, or sometimes irregular that this technique fail, and surgical intervention is required. Since 1974 Gruentzig balloon catheter has succeed when used for strictures in the cardiac and peripheral vasculatures, the biliary and urinary tracts, the colon of neonates after inflammatory disease and also in the esophagus. Fluoroscopically guided balloon catheters were used to dilate 30 esophageal strictures in 30 patients over 3 years at Department of Diagnostic Radiology, Chonnam University, College of Medicine. The distribution of age was from 7 years to 71 days and the ratio of male to female was 15:15. The causes of benign stricture (23 cases) were post-operative strictures (13), chemical (4), achalasia (3), chronic inflammation (2), esophageal rupture (1) and those of malignant stricture (7 cases) were post-radiation stricture of primary esophageal cancer (6) and metastatic esophageal cancer (1). The success rate of procedure was 93% (28/30). The causes of failure were the failure of passage of stricture due to markedly dilated proximal segment of esophagus (1 case) and too long segment of stricture (1 case). Complication of procedure was the diverticular-formation of esophagus in 3 cases, but has no clinical significance in follow-up esophagography. In conclusion, fluoroscopically guided balloon dilation of esophageal stricture appears to be safe, effective treatment and may be have theoretical advantages over conventional bougienage and also should be considered before other methods of treatment are used

  8. Ultra-high Modulus Nano-Fluoroelastomers

    Science.gov (United States)

    Pan, David H.

    2004-03-01

    The cross-linking densities, glass transition temperatures, and physical properties of fluoroelastomers filled with a nanometer-size particle have been determined as a function of filler concentration and co-solvent using both dry and wet filler incorporation methodologies. Addition of alcohol to the casting solvent such as methyl isobutyl ketone results in about a factor of 1.5-3 increase in elastic modulus for elastomer of the same filler concentration. It is discovered that a properly prepared nano-fluoroelastomer can exhibit as much as a two-order-of-magnitude increase in elastic modulus as the filler concentration increases from zero to 35 parts per hundred of rubber (phr) by weight while the glass transition temperature does not change substantially with filler concentration. The effect of cross-linking density on the elastic modulus for these materials will be discussed in this paper.

  9. The elastic modulus of isolated polytetrafluoroethylene filaments

    Directory of Open Access Journals (Sweden)

    Patrick Drawe

    2014-09-01

    Full Text Available We report vibrational Raman spectra of small extended perfluoro-n-alkanes (CnF2n+2 with n = 6, 8–10, 12–14 isolated in supersonic jet expansions and use wavenumbers of longitudinal acoustic vibrations to extrapolate the elastic modulus of cold, isolated polytetrafluoroethylene filaments. The derived value E = 209(10 GPa defines an upper limit for the elastic modulus of the perfectly crystalline, noninteracting polymer at low temperatures and serves as a benchmark for quantum chemical predictions.

  10. Hardness and Elastic Modulus of Titanium Nitride Coatings Prepared by Pirac Method

    Science.gov (United States)

    Wu, Siyuan; Wu, Shoujun; Zhang, Guoyun; Zhang, Weiguo

    In the present work, hardness and elastic modulus of a titanium nitride coatings prepared on Ti6Al4V by powder immersion reaction-assisted coating (PIRAC) are tested and comparatively studied with a physical vapor deposition (PVD) TiN coating. Surface hardness of the PIRAC coatings is about 11GPa, much lower than that of PVD coating of 22GPa. The hardness distribution profile from surface to substrate of the PVD coatings is steeply decreased from ˜22GPa to ˜4.5GPa of the Ti6Al4V substrate. The PIRAC coatings show a gradually decreasing hardness distribution profile. Elastic modulus of the PVD coating is about 426GPa. The PIRAC coatings show adjustable elastic modulus. Elastic modulus of the PIRAC coatings prepared at 750∘C for 24h and that at 800∘C for 8h is about 234 and 293GPa, respectively.

  11. Monoclonal Antibody Interfaces: Dilatation Mechanics and Bubble Coalescence.

    Science.gov (United States)

    Kannan, Aadithya; Shieh, Ian C; Leiske, Danielle L; Fuller, Gerald G

    2018-01-16

    Monoclonal antibodies (mAbs) are proteins that uniquely identify targets within the body, making them well-suited for therapeutic applications. However, these amphiphilic molecules readily adsorb onto air-solution interfaces where they tend to aggregate. We investigated two mAbs with different propensities to aggregate at air-solution interfaces. The understanding of the interfacial rheological behavior of the two mAbs is crucial in determining their aggregation tendency. In this work, we performed interfacial stress relaxation studies under compressive step strain using a custom-built dilatational rheometer. The dilatational relaxation modulus was determined for these viscoelastic interfaces. The initial value and the equilibrated value of relaxation modulus were larger in magnitude for the mAb with a higher tendency to aggregate in response to interfacial stress. We also performed single-bubble coalescence experiments using a custom-built dynamic fluid-film interferometer (DFI). The bubble coalescence times also correlated to the mAbs aggregation propensity and interfacial viscoelasticity. To study the influence of surfactants in mAb formulations, polyethylene glycol (PEG) was chosen as a model surfactant. In the mixed mAb/PEG system, we observed that the higher aggregating mAb coadsorbed with PEG and formed domains at the interface. In contrast, for the other mAb, PEG entirely covered the interface at the concentrations studied. We studied the mobility of the interfaces, which was manifested by the presence or the lack of Marangoni stresses. These dynamics were strongly correlated with the interfacial viscoelasticity of the mAbs. The influence of competitive destabilization in affecting the bubble coalescence times for the mixed mAb/PEG systems was also studied.

  12. Clinical review: Percutaneous dilatational tracheostomy

    Science.gov (United States)

    Al-Ansari, Mariam A; Hijazi, Mohammed H

    2006-01-01

    As the number of critically ill patients requiring tracheotomy for prolonged ventilation has increased, the demand for a procedural alternative to the surgical tracheostomy (ST) has also emerged. Since its introduction, percutaneous dilatational tracheostomies (PDT) have gained increasing popularity. The most commonly cited advantages are the ease of the familiar technique and the ability to perform the procedure at the bedside. It is now considered a viable alternative to (ST) in the intensive care unit. Evaluation of PDT procedural modifications will require evaluation in randomized clinical trials. Regardless of the PDT technique, meticulous preoperative and postoperative management are necessary to maintain the excellent safety record of PDT. PMID:16356203

  13. Thickness dependence of nanofilm elastic modulus

    Czech Academy of Sciences Publication Activity Database

    Fedorchenko, Alexander I.; Wang, A. B.; Cheng, H.H.

    2009-01-01

    Roč. 94, č. 15 (2009), s. 152111-152113 ISSN 0003-6951 Institutional research plan: CEZ:AV0Z20760514 Keywords : nanofilm * elastic modulus * thickness dependence Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.554, year: 2009 http://link.aip.org/link/?APPLAB/94/152111/1

  14. Structural relaxation monitored by instantaneous shear modulus

    DEFF Research Database (Denmark)

    Olsen, Niels Boye; Dyre, Jeppe; Christensen, Tage Emil

    1998-01-01

    time definition based on a recently proposed expression for the relaxation time, where G [infinity] reflects the fictive temperature. All parameters entering the reduced time were determined from independent measurements of the frequency-dependent shear modulus of the equilibrium liquid....

  15. A low elastic modulus Ti-Nb-Hf alloy bioactivated with an elastin-like

    OpenAIRE

    González, Marta; Salvagni, Emiliano; Rodríguez Cabello, J.C.; Rupérez de Gracia, Elisa; Gil Mur, Francisco Javier; Manero Planella, José María; Peña, Javier

    2012-01-01

    b-type titanium alloys with low Young’s modulus are desirable to reduce stress shielding effect and enhance bone remodeling for implants used to substitute failed hard tissue. For biomaterials application, the surface bioactivity is necessary to achieve optimal osseointegration. In the previous work, the low elastic modulus (43 GPa) Ti-25Nb-16Hf (wt %) alloy was mechanically and microstructurally characterized. In the present work, the biological behavior of Ti-25Nb- 1...

  16. Geometrical modulus of a casting and its influence on solidification process

    Directory of Open Access Journals (Sweden)

    F. Havlicek

    2011-10-01

    Full Text Available Object: The work analyses the importance of the known criterion for evaluating the controlled solidification of castings, so called geometrical modulus defined by N. Chvorinov as the first one. Geometrical modulus influences the solidification process. The modulus has such specificity that during the process of casting formation it is not a constant but its initial value decreases with the solidification progress because the remaining melt volume can decrease faster than its cooling surface.Methodology: The modulus is determined by a simple calculation from the ratio of the casting volume after pouring the metal in the mould to the cooled mould surface. The solidified metal volume and the cooled surface too are changed during solidification. That calculation is much more complicated. Results were checked up experimentally by measuring the temperatures in the cross-section of heavy steel castings during cooling them.Results: The given experimental results have completed the original theoretical calculations by Chvorinov and recent researches done with use of numerical calculations. The contribution explains how the geometrical modulus together with the thermal process in the casting causes the higher solidification rate in the axial part of the casting cross-section and shortening of solidification time. Practical implications: Change of the geometrical modulus negatively affects the casting internal quality. Melt feeding by capillary filtration in the dendritic network in the casting central part decreases and in such a way the shrinkage porosity volume increases. State of stress character in the casting is changed too and it increases.

  17. Dynamical and hamiltonian dilations of stochastic processes

    International Nuclear Information System (INIS)

    Baumgartner, B.; Gruemm, H.-R.

    1982-01-01

    This is a study of the problem, which stochastic processes could arise from dynamical systems by loss of information. The notions of ''dilation'' and ''approximate dilation'' of a stochastic process are introduced to give exact definitions of this particular relationship. It is shown that every generalized stochastic process is approximately dilatable by a sequence of dynamical systems, but for stochastic processes in full generality one needs nets. (Author)

  18. Aneurysmatic dilatation of the vena portae

    International Nuclear Information System (INIS)

    Dewes, W.; Gormanns, R.; Spangenberger, W.; Staedtisches Krankenhaus Koeln-Merheim

    1986-01-01

    Anomaleous deviations of the portal venous system are relatively rarely obseved, but ineurysmatic dilatation of the vena portae, or one of its main branches, is an absolute rarity. Aneurysma of the vena portae is defined as a circumscribed dilatation of the vene to more than double the volume of the pre- or postaneurysmatic lumen. Modern, high-resolution ultrasound equipment is well able to diagnose with high reliability an aneurysmatic dilatation of the vena portae. (orig.) [de

  19. Acoustic Emission Characteristics of Gas-Containing Coal during Loading Dilation Process

    Directory of Open Access Journals (Sweden)

    Z. Q. Yin

    2015-12-01

    Full Text Available Raw coal was used as the study object in this paper to identify the evolution characteristics of acoustic emission (AE during the dilation process of gas-containing coal. The coal specimens were stored in gas seal devices filled with gas at different pressures (0, 0.5, 1.0, and 1.5 MPa for 24 h prior to testing. Then, the specimens were tested in a rock-testing machine, and the deformation and crack fracture patterns were recorded by using strain gauges and an AE system. The axial and volumetric strains–stress curves were analyzed in relation to the AE and the failure mode. Results show that as gas pressure increases, the uniaxial compression strength and elasticity modulus of gas-containing coal decreases, whereas the Poisson’s ratio increases. In all the coal specimens, the dilation initiation stress decreases, and the dilation degree increases. During the dilation process, before the loaded coal specimens reach peak stress, and as the load increases, the changes in the specimens and in the AE energy parameter of specimens can be divided into four phases: crack closure deformation, elastic deformation, stable crack propagation, and unstable crack propagation (dilation process. Across the four phases, the AE energy increases evidently during crack closure and elastic deformation but decreases during stable crack propagation. As the gas pressure increases, the AE signal frequency increases from 4.5 KHz to 8.1 KHz during the dilation process. Thus, the gas presence in coal specimens exerts a significant influence on the closure of sample cracks and dilation damage.

  20. Microscopic origin of volume modulus inflation

    Energy Technology Data Exchange (ETDEWEB)

    Cicoli, Michele [ICTP, Strada Costiera 11, Trieste 34014 (Italy); Dipartimento di Fisica e Astronomia, Università di Bologna, via Irnerio 46, 40126 Bologna (Italy); INFN, Sezione di Bologna, via Irnerio 46, 40126 Bologna (Italy); Muia, Francesco [Dipartimento di Fisica e Astronomia, Università di Bologna, via Irnerio 46, 40126 Bologna (Italy); INFN, Sezione di Bologna, via Irnerio 46, 40126 Bologna (Italy); Pedro, Francisco Gil [Departamento de Fisica Teórica UAM and Instituto de Fisica Teórica UAM/CSIC, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid (Spain)

    2015-12-21

    High-scale string inflationary models are in well-known tension with low-energy supersymmetry. A promising solution involves models where the inflaton is the volume of the extra dimensions so that the gravitino mass relaxes from large values during inflation to smaller values today. We describe a possible microscopic origin of the scalar potential of volume modulus inflation by exploiting non-perturbative effects, string loop and higher derivative perturbative corrections to the supergravity effective action together with contributions from anti-branes and charged hidden matter fields. We also analyse the relation between the size of the flux superpotential and the position of the late-time minimum and the inflection point around which inflation takes place. We perform a detailed study of the inflationary dynamics for a single modulus and a two moduli case where we also analyse the sensitivity of the cosmological observables on the choice of initial conditions.

  1. Microscopic origin of volume modulus inflation

    Science.gov (United States)

    Cicoli, Michele; Muia, Francesco; Gil Pedro, Francisco

    2015-12-01

    High-scale string inflationary models are in well-known tension with low-energy supersymmetry. A promising solution involves models where the inflaton is the volume of the extra dimensions so that the gravitino mass relaxes from large values during inflation to smaller values today. We describe a possible microscopic origin of the scalar potential of volume modulus inflation by exploiting non-perturbative effects, string loop and higher derivative perturbative corrections to the supergravity effective action together with contributions from anti-branes and charged hidden matter fields. We also analyse the relation between the size of the flux superpotential and the position of the late-time minimum and the inflection point around which inflation takes place. We perform a detailed study of the inflationary dynamics for a single modulus and a two moduli case where we also analyse the sensitivity of the cosmological observables on the choice of initial conditions.

  2. Dilation Behavior of Thermal Spray Coatings

    Science.gov (United States)

    Bejarano Lopez, Miryan Lorena

    Thermal Spray (TS) is a very versatile manufacturing process to deposit thick coatings on a variety of substrates. Coatings are used in protective (i.e. wear, chemical attack, high temperature, etc.) and functional (i.e. sensors) applications. TS coatings have a unique lamellar microstructure as a result of the overlapping of millions of molten and partially-molten particles. During processing, high deformation by impact, high temperature, and rapid solidification lead to a complex hierarchical material system that contains a high amount of microstructural defects. The presence of defects in the microstructure contribute to differences in property values in comparison to bulk materials. Thermal stresses and residual strains arise from processing, thermal gradients and thermal exposure. Evaluation of thermal properties, in this case, the coefficient of thermal expansion (CTE) is of vital importance to enhance coating performance. In this dissertation, expansion measurements of various metals, alloys, ceramics, and cermet coatings; were carried out using various techniques (push rod dilatometry, x-ray diffraction XRD, digital image correlation DIC, and curvature method) to determine the dilation behavior at the atomic, micro- and macro-scale levels. The main results were. 1) Mathematical models (Turner and Kerner) used for composite materials, successfully predicted the CTE property of a TS coating where the primary phase is the coating material and the secondary phases can be oxides, precipitates, etc. (formed as a byproduct of the spraying process). CTE was found not to be affected by porosity. 2) Despite the anisotropic behavior characteristic of TS coatings, the experimental results shown that CTE results to be reasonable isotropic within the scope of this study. 3) The curvature method was found to be an alternative technique to obtain the CTE, as well as the Young's modulus of coating in a bi-material strip, with good approximation. 4) An anomalous expansion

  3. Fibonacci difference sequence spaces for modulus functions

    Directory of Open Access Journals (Sweden)

    Kuldip Raj

    2015-05-01

    Full Text Available In the present paper we introduce Fibonacci difference sequence spaces l(F, Ƒ, p, u and  l_∞(F, Ƒ, p, u by using a sequence of modulus functions and a new band matrix F. We also make an effort to study some inclusion relations, topological and geometric properties of these spaces. Furthermore, the alpha, beta, gamma duals and matrix transformation of the space l(F, Ƒ, p, u are determined.

  4. Theory of thermal expansivity and bulk modulus

    International Nuclear Information System (INIS)

    Kumar, Munish

    2005-01-01

    The expression for thermal expansivity and bulk modulus, claimed by Shanker et al. to be new [Physica B 233 (1977) 78; 245 (1998) 190; J. Phys. Chem. Solids 59 (1998) 197] are compared with the theory of high pressure-high temperature reported by Kumar and coworkers. It is concluded that the Shanker formulation and the relations based on this are equal to the approach of Kumar et al. up to second order

  5. Modulus for the coal ash. Summary

    Energy Technology Data Exchange (ETDEWEB)

    Rank, V.

    1944-06-30

    This summary outlined the procedure for obtaining a modulus to determine the effects of varying ash content. This modulus was to indicate the relative amounts of aluminum oxide and silicon dioxide after addition of alkalais or alkaline-earth constituents found in catalysts. The calculation of the modulus was based upon stoichiometric ratios of these oxides to other major components of ash as represented in the major minerals in the ash. The assumptions about the conditions in low- to intermediate-temperature coking included the following: (1) magnesium oxide was found only in biotite, which contained potassium oxide, magnesium oxide, aluminum oxide, silicon dioxide, and water in the respective mole ratios 1:4:2:6:1. (2) Potassium oxide outside of biotite was found only in muscovite, which contained potassium oxide, aluminum oxide, silicon dioxide, and water in the respective mole ratios 1:1:6:2. (3) Sodium oxide was combined only with aluminum oxide and silicon dioxide in the mole ratios 1:1:6. (4) Phosphoric acid was found as aluminum phosphate. (5) Lime was found in anortite, which contained calcium sulfate, calcium carbonate, or calcium oxide combined with aluminum oxide and silicon dioxide in the mole ratios 1:1:2. (6) Aluminum oxide and silicon dioxide existed mainly in the hydrated state with the two of them combined with water in the mole ratios 1:2:2. The completed formula for the modulus was given as M = (aluminum oxide) + (silicon dioxide) - 0.65(magnesium oxide) - 4.90(potassium oxide + sodium oxide) - 3.96(calcium oxide) - 0.72(phosphorous pentoxide), where the parentheses should be filled by numbers in weight units for the respective compounds.

  6. [Percutanous dilation tracheotomy: our experience].

    Science.gov (United States)

    Domènech, I; Mateu, T; Cisa, E; Juan, A; Gil, E; Palau, M; Dicenta, M

    2004-01-01

    Percutaneous dilation Tracheotomy (PDT) is becoming a popular alternative to surgical tracheotomy. In our hospital, we recently adopted the use of the PDT in intensive care unit patients. The objective [corrected] of this investigation is to characterize and quantify the rate of complications for PDT. A prospective study of 60 PDT performed at different intesive care units, betweem September 2002 to July 2003. The intraoperative time for PDT was 8 minutes. Complications included 6 cases of mild intraoperative hemorrhage, 1 case of moderate intraoperative hemorrhage, 4 cases of mild postoperative hemorrhage and 1 case of subcutaneous emphysema. PDT is a good alternative to surgical tracheotomy and should be added to the otolaryngologists armamentarium of surgical airway procedures.

  7. Present status of dilatative arteriopathy (Dolichoectasia)

    International Nuclear Information System (INIS)

    Wu Xi; Liu Jianmin

    2008-01-01

    Dilatative arteriopathy is also called Dolichoectasia, presenting as enlarged, tortuous, and dilated arteries; especially with involvement of intracranial arteries. The incidence of dolichoectasia is quite low, but it may induce recurrent strokes with poor prognosis and up to now there is no specific management. Our study reviews the potential etiology, epidemiology, symptoms, pathophysiology, prognosis and present status of treatment for dolichoectasia. (authors)

  8. Congenital segmental dilatation of the colon

    African Journals Online (AJOL)

    Congenital segmental dilatation of the colon is a rare cause of intestinal obstruction in neonates. We report a case of congenital segmental dilatation of the colon and highlight the clinical, radiological, and histopathological features of this entity. Proper surgical treatment was initiated on the basis of preoperative radiological ...

  9. Percutaneous balloon dilatation for benign hepaticojejunostomy strictures

    NARCIS (Netherlands)

    Vos, P. M.; van Beek, E. J.; Smits, N. J.; Rauws, E. A.; Gouma, D. J.; Reeders, J. W.

    2000-01-01

    BACKGROUND: Percutaneous balloon dilatation of biliary tract strictures is generally accepted as a safe and inexpensive procedure. The effectiveness in selected groups of patients remains under discussion. The purpose of this study was to evaluate the results of percutaneous balloon dilatation in

  10. One-day transhepatic billary stricture dilatation

    International Nuclear Information System (INIS)

    Mueller, P.R.; Saini, S.; Hahn, P.F.; Silverman, S.G.; Ferrucci, J.T.

    1989-01-01

    To overcome technical problems in percutaneous transhepatic dilatation or biliary strictures, the authors performed the entire procedure in a single session with the patient under general anesthesia (N = 7). Six patients had a biliary-enteric anastomosis, and one patient had a traumatic mid common bile duct stricture. All bile ducts were of normal caliber or were minimally dilated by US or transhepatic cholangiography. Dilatation was performed via a fresh transhepatic drainage catheter in six patients and via an in-dwelling T-tube in one patient. High-pressure balloons (10-12 mm) were placed after catheter dilation of the tract, and balloons were inflated for 5-10 minutes three to five times. Dilation was stopped with a waist was no longer present. No strictures have recurred in patients followed up to 24 months

  11. Asphalt mix characterization using dynamic modulus and APA testing.

    Science.gov (United States)

    2005-11-01

    final report summarizes two research efforts related to asphalt mix characterization: dynamic modulus and Asphalt Pavement Analyzer testing. One phase of the research consisted of a laboratory-based evaluation of dynamic modulus of Oregon dense-grade...

  12. Aortic root dilatation among young competitive athletes: echocardiographic screening of 1929 athletes between 15 and 34 years of age.

    Science.gov (United States)

    Kinoshita, N; Mimura, J; Obayashi, C; Katsukawa, F; Onishi, S; Yamazaki, H

    2000-04-01

    Aortic dilatation can be lethal for young competitive athletes. The prevalence among athletes is not known, however, and thus a reasonable approach to early recognition remains uncertain. Echocardiograms of 1929 normotensive athletes 15 to 34 years of age were analyzed. Five (0.26%) athletes had aortic dilatation; 4 of the 5 played basketball. This made the prevalence of aortic dilatation 0.96% (4 of 415) among basketball and volleyball players, who represented a population of especially tall athletes. Tallness aside, only 2 of the 5 athletes had features of Marfan syndrome. Among the athletes without aortic dilatation, the relation between body surface area and aortic root dimension was nonlinear and best described with a quadratic regression model. Athletes with aortic dilatation fell well outside the 95% confidence interval. Because a higher incidence of aortic dilatation is to be anticipated among very tall athletes, inclusion of echocardiography in screening before participation in certain sports should be considered.

  13. Nondestructive Measurement of Dynamic Modulus for Cellulose Nanofibril Films

    Science.gov (United States)

    Yan Qing; Robert J. Ross; Zhiyong Cai; Yiqiang Wu

    2013-01-01

    Nondestructive evaluation of cellulose nanofibril (CNF) films was performed using cantilever beam vibration (CBV) and acoustic methods to measure dynamic modulus. Static modulus was tested using tensile tension method. Correlation analysis shows the data measured by CBV has little linear relationship with static modulus, possessing a correlation coefficient (R

  14. Young Modulus of Crystalline Polyethylene from ab Initio Molecular Dynamics

    NARCIS (Netherlands)

    Hageman, J.C.L.; Meier, Robert J.; Heinemann, M.; Groot, R.A. de

    1997-01-01

    The Young modulus for crystalline polyethylene is calculated using ab initio molecular dynamics based on density functional theory in the local density approximation (DFT-LDA). This modulus, which can be seen as the ultimate value for the Young modulus of polyethylene fibers, is found to be 334 GPa.

  15. Effect of bulk modulus on performance of a hydrostatic transmission ...

    Indian Academy of Sciences (India)

    results demonstrates that bulk modulus should be considered as a variable parameter to obtain a more realistic model. Additionally, a PID controller is insufficient in presence of variable bulk modulus, whereas a fuzzy controller provides robust angular velocity control. Keywords. Hydrostatic transmission; bulk modulus; PID ...

  16. Dilational Response of Voided Polycrystals

    Science.gov (United States)

    Savage, Daniel J.; Cazacu, Oana; Knezevic, Marko

    2017-05-01

    Finite-element (FE) cell model computations have been used to gain insights into the ductile response of porous polycrystals. Generally, the behavior of the matrix is described by a J 2-plasticity model. In this article, we present a new computational approach to FE cell models for porous polycrystals deforming by slip based on crystal plasticity. The cell provides the homogenized dilational response, where the constitutive response of every integration point is based on a single-crystal visco-plasticity law. The calculations are performed for a body-centered cubic polycrystal with random texture. Axisymmetric tensile and compressive loadings are imposed corresponding to the fixed values of the stress triaxiality and to two possible values of the Lode parameter. The resulting numerical yield points are compared with those obtained using a J 2-FE cell and an analytical model. The predictions confirm the combined effects of the mean stress and third-invariant on yielding recently revealed by the analytical model.

  17. Percutaneous catheter dilatation of carotid stenoses

    International Nuclear Information System (INIS)

    Mathias, K.; Mittermayer, C.; Ensinger, H.; Neff, W.

    1980-01-01

    Thirty-one carotid artery stenoses were produced in thirty dogs by three different techniques. Twenty-three of these could be cured by transfemoral percutaneous catheter dilatation. High grade tight stenoses may present resistance which cannot be overcome by the catheter. Histological examination of the dilated vessels showed circumscribed changes in the vessel wall, with destruction of elastic membranes. From our experience of catheter dilatation of pelvic and lower limb arteries and of renal arteries, we consider it feasible to use this technique in selected patients with carotid stenosis. (orig.) [de

  18. Dynamic modulus of nanosilica modified porous asphalt

    Science.gov (United States)

    Arshad, A. K.; Masri, K. A.; Ahmad, J.; Samsudin, M. S.

    2017-11-01

    Porous asphalt (PA) is a flexible pavement layer with high interconnected air void contents and constructed using open-graded aggregates. Due to high temperature environment and increased traffic volume in Malaysia, PA may have deficiencies particularly in rutting and stiffness of the mix. A possible way to improve these deficiencies is to improve the asphalt binder used. Binder is normally modified using polymer materials to improve its properties. However, nanotechnology presently is being gradually used for asphalt modification. Nanosilica (NS), a byproduct of rice husk and palm oil fuel ash is used as additive in this study. The aim of this study is to enhance the rutting resistance and stiffness performance of PA using NS. This study focused on the performance of PA in terms of dynamic modulus with the addition of NS modified binder to produce better and more durable PA. From the result of Dynamic SPT Test, it shows that the addition of NS was capable in enhancing the stiffness and rutting resistance of PA. The addition of NS also increase the dynamic modulus value of PA by 50%.

  19. A Two-Step Methodology to Study the Influence of Aggregation/Agglomeration of Nanoparticles on Young's Modulus of Polymer Nanocomposites

    Science.gov (United States)

    Ma, Xinyue; Zare, Yasser; Rhee, Kyong Yop

    2017-12-01

    A two-step technique based on micromechanical models is suggested to determine the influence of aggregated/agglomerated nanoparticles on Young's modulus of polymer nanocomposites. The nanocomposite is assumed to include nanoparticle aggregation/agglomeration and effective matrix phases. This method is examined for different samples, and the effects of important parameters on the modulus are investigated. Moreover, the highest and the lowest levels of predicted modulus are calculated based on the current methodology. The suggested technique can correctly predict Young's modulus for the samples assuming the aggregation/agglomeration of nanoparticles. Additionally, the aggregation/agglomeration of nanoparticles decreases Young's modulus of polymer nanocomposites. It is demonstrated that the high modulus of nanoparticles is not sufficient to obtain a high modulus in nanocomposites, and the surface chemistry of components should be adjusted to prevent aggregation/agglomeration and to disperse nano-sized particles in the polymer matrix.

  20. Study on Size-Dependent Young’s Modulus of a Silicon Nano beam by Molecular Dynamics Simulation

    International Nuclear Information System (INIS)

    Yu, H.; Sun, C.; Zhang, W.W.; Lei, S.Y.; Huang, K.A.

    2013-01-01

    Young’s modulus of a silicon nano beam with a rectangular cross-section is studied by molecular dynamics method. Dynamic simulations are performed for doubly clamped silicon nano beams with lengths ranging from 4.888 to 12.491 nm and cross-sections ranging from 1.22 nm ×1.22 nm to 3.39 nm × 3.39 nm. The results show that Young’s moduli of such small silicon nano beams are much higher than the value of Young’s modulus for bulk silicon. Moreover, the resonant frequency and Young’s modulus of the Si nano beam are strongly dependent not only on the size of the nano beam but also on surface effects. Young’s modulus increases significantly with the decreasing of the thickness of the silicon nano beam. This result qualitatively agrees with one of the conclusions based on a semi continuum model, in which the surface relaxation and the surface tension were taken into consideration. The impacts of the surface reconstruction with (2 ×1) dimmers on the resonant frequency and Young’s modulus are studied in this paper too. It is shown that the surface reconstruction makes the silicon nano beam stiffer than the one without the surface reconstruction, resulting in a higher resonant frequency and a larger Young’s modulus

  1. Genetics Home Reference: familial dilated cardiomyopathy

    Science.gov (United States)

    ... familial dilated cardiomyopathy can include an irregular heartbeat (arrhythmia), shortness of breath (dyspnea), extreme tiredness (fatigue), fainting ... Celebrates Its 15th Anniversary National DNA Day 2018 Newborn Screening Saves Lives Act Turns 10 All Bulletins ...

  2. An Erupted Dilated Odontoma: A Rare Presentation

    Directory of Open Access Journals (Sweden)

    Gaurav Sharma

    2016-01-01

    Full Text Available A dilated odontoma is an extremely rare developmental anomaly represented as a dilatation of the crown and root as a consequence of a deep, enamel-lined invagination and is considered a severe variant of dens invaginatus. An oval shape of the tooth lacking morphological characteristics of a crown or root implies that the invagination happened in the initial stages of morphodifferentiation. Spontaneous eruption of an odontoma is a rare occurrence and the occurrence of a dilated odontoma in a supernumerary tooth is even rarer with only a few case reports documented in the English literature. We present an extremely rare case of erupted dilated odontoma occurring in the supernumerary tooth in anterior maxillary region in an 18-year-old male, which, to the best of our knowledge, is the first ever case reported in English literature.

  3. An Erupted Dilated Odontoma: A Rare Presentation

    Science.gov (United States)

    Sharma, Gaurav; Nagra, Amritpreet; Singh, Gurkeerat; Nagpal, Archna; Soin, Atul; Bhardwaj, Vishal

    2016-01-01

    A dilated odontoma is an extremely rare developmental anomaly represented as a dilatation of the crown and root as a consequence of a deep, enamel-lined invagination and is considered a severe variant of dens invaginatus. An oval shape of the tooth lacking morphological characteristics of a crown or root implies that the invagination happened in the initial stages of morphodifferentiation. Spontaneous eruption of an odontoma is a rare occurrence and the occurrence of a dilated odontoma in a supernumerary tooth is even rarer with only a few case reports documented in the English literature. We present an extremely rare case of erupted dilated odontoma occurring in the supernumerary tooth in anterior maxillary region in an 18-year-old male, which, to the best of our knowledge, is the first ever case reported in English literature. PMID:26989523

  4. Fluoroscopic guided benign oesophageal stricture dilatation in ...

    African Journals Online (AJOL)

    Gilliard bougienage (SGB) with balloon dilatation and the combination of both methods for the treatment of BOSs in children at Universitas Hospital, Bloemfontein, South Africa. Methods. A retrospective review of the patient notes on all children 12 ...

  5. On $rho$-dilations of commuting operators

    Czech Academy of Sciences Publication Activity Database

    Müller, Vladimír

    2017-01-01

    Roč. 78, č. 1 (2017), s. 3-20 ISSN 0379-4024 R&D Projects: GA ČR(CZ) GA14-07880S Institutional support: RVO:67985840 Keywords : regular unitary dilation * rho-dilation Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 0.524, year: 2016 http://www.mathjournals.org/jot/2017-078-001/2017-078-001-001.html

  6. On $rho$-dilations of commuting operators

    Czech Academy of Sciences Publication Activity Database

    Müller, Vladimír

    2017-01-01

    Roč. 78, č. 1 (2017), s. 3-20 ISSN 0379-4024 R&D Projects: GA ČR(CZ) GA14-07880S Institutional support: RVO:67985840 Keywords : regular unitary dilation * rho-dilation Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 0.524, year: 2016 http://www.mathjournals.org/jot/2017-078-001/2017-078-001-001. html

  7. Influence of Dilation on the Strength of Sand – Steel Interfaces

    Science.gov (United States)

    Dolzyk-Szypcio, Katarzyna

    2017-12-01

    In this paper the sand-steel interface behaviour is analysed on the basis of frictional state theory. It is shown that for a small stress level the influence of dilatancy is fundamentally similar for sand-steel and sand-sand behaviour for a direct shear test. The use of the new parameter describes the influence of surface roughness on stress-dilatancy relationship. The peak strength of sand-steel is analysed. Values of the new parameter grow with normalised roughness for smooth surface and are constant for intermediate and rough surfaces. It is also shown that values of normalised friction coefficient obtained theoretically are similar with those shown in literature.

  8. Determination of Lubricant Bulk Modulus in Metal Forming by Means of a Simple Laboratory Test and Inverse FEM Analysis

    DEFF Research Database (Denmark)

    Hafis, S. M.; Christiansen, P.; Martins, P. A. F.

    2016-01-01

    facilitates the lubricant entrainment, pressurization and possible escape by micro-plasto-hydrodynamic lubrication. In order to model these mechanisms an important lubricant propertyd esignated as the bulk modulus is needed for characterizing the compressibility of the lubricant. The present paper describes...... a simple, practical test to determine the bulk modulus. Combination of the experimental upsetting of an axisymmetric metal workpiece containing a truncated conical surface pocket with an inverse finite element analysis of the test allows determining the lubricant bulk modulus. The finite element analysis...

  9. The effect of fluid saturation on the dynamic shear modulus of tight sandstones

    Science.gov (United States)

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

    2017-10-01

    Tight sandstones have become important targets in the exploration of unconventional oil and gas reservoirs. However, due to low porosity, low permeability, complex pore structure and other petrophysical properties of tight sandstones, the applicability of Gassmann’s fluid substitution procedure becomes debatable. Aiming at this problem, this paper attempts to explore the applicability of Gassmann’s theory in tight sandstones. Our focus is to investigate the sensitivity of dynamic shear modulus to fluid saturation and the possible mechanism. Ultrasonic velocity in dry and saturated tight sandstone samples was measured in the laboratory under an effective pressure within the range of 1-60 MPa. This study shows that the shear modulus of the water-saturated samples appears to either increase or decrease, and the soft porosity model (SPM) can be used to quantitatively estimate the variation of shear modulus. Under the condition of in situ pressure, samples dominated by secondary pores and microcracks are prone to show shear strengthening with saturation, which is possibly attributed to the local flow dispersion. Samples that mainly have primary pores are more likely to show shear weakening with saturation, which can be explained by the surface energy mechanism. We also find good correlation between changes in shear modulus and inaccurate Gassmann-predicted saturated velocity. Therefore, understanding the variation of shear modulus is helpful to improving the applicability of Gassmann’s theory in tight sandstones.

  10. Influence of the type of measuring device in determining the static modulus of elasticity of concrete

    Directory of Open Access Journals (Sweden)

    S. S. Araújo

    Full Text Available This paper presents a comparative analysis of the results obtained in static modulus of elasticity tests of plain concrete cylindrical specimens. The purpose of this study is to identify and evaluate the influence of several factors involved in modulus of elasticity tests such as the strain measurement device used (dial indicators, electrical surface bonded strain gages, externally fixed strain gages and linear variation displacement transducer - LVDT, the type of concrete (Class C30 and Class C60 and cylindrical specimen size (100 mm x 200 mm and 150 mm x 300 mm. The modulus tests were done in two different laboratories in the Goiânia, GO region and were performed according to code ABNT NBR 8522:2008, which describes the initial tangent modulus test, characterized by strains measured at tension values of 0.5 MPa and 30% of the ultimate load. One hundred and sixty specimens were tested with statistically satisfactory results. It was concluded that the type of strain measurement device greatly influenced the modulus of elasticity results. Tests in specimens 100 mm x 200 mm showed highest statistical variation.

  11. Dilatation or no dilatation of the cervix during cesarean section (Dondi Trial): a randomized controlled trial.

    Science.gov (United States)

    Kirscht, Jade; Weiss, Christel; Nickol, Jana; Berlit, Sebastian; Tuschy, Benjamin; Hoch, Benjamin; Trebin, Amelie-Verena; Große-Steffen, Thomas; Sütterlin, Marc; Kehl, Sven

    2017-01-01

    To assess the effects of mechanical dilatation of the cervix during cesarean section on postoperative morbidity. A total of 447 women with elective cesarean section were included in the Dondi trial (Dilatation or no dilatation of the cervix during cesarean section). The primary outcome measure of this randomized controlled trial was postpartum hemorrhage (PPH) within 6 weeks. Infectious morbidity (puerperal fever, endometritis, wound infection, and urinary tract infection), blood loss (need for blood transfusion or change in hemoglobin levels), and operating time were also evaluated. The rate of PPH within 6 weeks was not different between the two groups [dilatation group: 5 (2.4 %), no dilatation group: 3 (1.2 %), p = 0.479]. Infectious morbidity, blood loss, and operating time were not diverse as well. The only significant difference between the two groups was the rate of retained products of conception with fewer cases after cervical dilatation (0 versus 6.2 %, p cesarean section compared with no dilatation of the cervix did not influence the risk of postpartum hemorrhage. However, there were fewer cases with retained products of conception after dilatation.

  12. The neural substrates of subjective time dilation

    Directory of Open Access Journals (Sweden)

    Marc Wittmann

    2010-02-01

    Full Text Available An object moving towards an observer is subjectively perceived as longer in duration than the same object that is static or moving away. This 'time dilation effect' has been shown for a number of stimuli that differ from standard events along different feature dimensions (e.g. color, size, and dynamics. We performed an event-related functional magnetic resonance imaging (fMRI, while subjects viewed a stream of five visual events, all of which were static and of identical duration except the fourth one, which was a deviant target consisting of either a looming or a receding disc. The duration of the target was systematically varied and participants judged whether the target was shorter or longer than all other events. A time dilation effect was observed only for looming targets. Relative to the static standards, the looming as well as the receding targets induced increased activation of the anterior insula and anterior cingulate cortices (the “core control network”. The decisive contrast between looming and receding targets representing the time dilation effect showed strong asymmetric activation and, specifically, activation of cortical midline structures (the “default network”. These results provide the first evidence that the illusion of temporal dilation is due to activation of areas that are important for cognitive control and subjective awareness. The involvement of midline structures in the temporal dilation illusion is interpreted as evidence that time perception is related to self-referential processing.

  13. Effects of crack-dilatancy on Rayleigh waves in fluid-saturated ...

    African Journals Online (AJOL)

    Secular equations are derived in closed form for the propagation of Rayleigh waves in the porous media with sealed or fullyopened surface pores. The velocity of ... The opening of surface pores may be an important reason for a faster propagation of Rayleigh waves in any realistic elastic medium. Finally, the dilatancy due ...

  14. Retrograde transurethral balloon dilation of the prostate

    International Nuclear Information System (INIS)

    Castaneda, F.; Reddy, P.; Wasserman, N.F.; Lund, G.; Hulbert, J.; Hunter, D.; Castaneda-Zuniga, W.R.; Amplatz, K.

    1986-01-01

    A series of patients with documented benign prostatic hypertrophy evaluated by urodynamic studies, voiding cystourethrography, retrograde urethrography, and MR imaging underwent dilation performed using a retrograde transurethral approach with 25-mm balloon dilators inflated at a pressure of 3-4 atm for 10 minutes. Immediately after the procedure, retrograde and voiding cystourethrography as well as MR imaging were performed. A Foley catheter was left in place for 24 hours. Complete relief of symptoms has occurred in all of the patients during the follow-up period. No significant complications other than transient hematuria resulted from the procedure. Results of the comparison studies and of MR imaging are discussed

  15. Determination of elastic modulus in nickel alloy from ultrasonic ...

    Indian Academy of Sciences (India)

    als scientists, and solid-state theorists; they connect to tech- nological, structural economics and safety, to various mate- rials phenomena and to their fundamental interatomic forces. (Ledbetter 1983). In any material which is a multiphase alloy, the elastic modulus is determined by the modulus of the indi- vidual phases and ...

  16. Generalized Vector-Valued Sequence Spaces Defined by Modulus Functions

    Directory of Open Access Journals (Sweden)

    Işik Mahmut

    2010-01-01

    Full Text Available We introduce the vector-valued sequence spaces , , and , and , using a sequence of modulus functions and the multiplier sequence of nonzero complex numbers. We give some relations related to these sequence spaces. It is also shown that if a sequence is strongly -Cesàro summable with respect to the modulus function then it is -statistically convergent.

  17. On Young's modulus of multi-walled carbon nanotubes

    Indian Academy of Sciences (India)

    WINTEC

    multi-walled nanotubes have a modulus > 1060 GPa (that of graphene sheet) is currently not understood. However, in the present paper, a novel analysis based on transmi- ssion electron microscopy of carbon nanotube/aluminum nanocomposites is given to calculate approximately the. Young's modulus of multi-walled ...

  18. Improved Model of Rock Mass Dilatation.

    Science.gov (United States)

    1985-05-29

    uartzite ( Bieniawski , 1967), granite (Brace et al., 1966; Zoback and Byerlee, 1975), .-- marble, sandstone, limestone, etc. Dilatancy therefore appears...prepared for Defense Nuclear Agency. 2. Algorithm 392 of CACM, "Systems of Hyperbolic Partial Differential Equations." 3. Bieniawski , Z.T. (1967

  19. Dilation and Curettage (D&C)

    Science.gov (United States)

    ... Dilation and Curettage (D&C) Page Navigation ▼ ACOG Pregnancy Book Patient Education FAQs Patient Education Pamphlets - Spanish FAQ062, February 2016 ... written permission from the publisher. Related FAQs Early Pregnancy Loss (Miscarriage) (FAQ090) Abnormal Uterine Bleeding ... Committee Opinions Practice Bulletins Patient ...

  20. Ventricular dilatation in aging and dementia

    NARCIS (Netherlands)

    Palm, Walter Miguel

    2015-01-01

    The general objective of this thesis was to study the causes and consequences of ventricular dilatation in aging and dementia. For this purpose, we used ventricular shape analysis to study potential new MRI markers of cognitive decline in aging, subjective memory complaints, mild cognitive

  1. A Symmetry Approach to Time Dilation.

    Science.gov (United States)

    Dunne, Peter

    1995-01-01

    Outlines an approach to introduce students to special relativity using a discussion of stopclocks and measurement of the transmission of light pulses to produce a natural derivation of the time dilation factor. Aims at providing a frame of reference from which they can be tempted to explore special relativity at a more sophisticated level. (JRH)

  2. Hydraulic urethral dilatation after optical internal urethrotomy ...

    African Journals Online (AJOL)

    Objectives: To determine the rate of early recurrence of urethral stricture in the first six months in patients who perform hydraulic urethral dilatation(HUD) after optical internal urethrotomy (OIU) and compare the early recurrence Fate in patients who perform HUD after OIU with the recurrence rates in patients reported in the ...

  3. Intestinal Infarctus following Dilatation and Uterine Curettage

    Directory of Open Access Journals (Sweden)

    N.M. Ngowe

    2007-03-01

    Full Text Available We present a case of intestinal infarctus through the vagina. This was a consequence of induced abortion done clandestinely. The main objective was to point out the surgical complications of uterine dilatation and curettage by means of this rare case.

  4. Apparent unambiguousness of relativistic time dilation

    International Nuclear Information System (INIS)

    Strel'tsov, V.N.

    1992-01-01

    It is indicated on the definite analogy between the dependence of visible sizes of relativistic objects and period of the wave, emitted by the moving source from the observation conditions ('retradition factor'). It is noted that the definition of time for moving extended objects, led to relativistic dilation, corresponds to the definition of the relativistic (radar) length led to the 'elongation formula'. 10 refs

  5. Effective elastic modulus of isolated gecko setal arrays.

    Science.gov (United States)

    Autumn, K; Majidi, C; Groff, R E; Dittmore, A; Fearing, R

    2006-09-01

    Conventional pressure sensitive adhesives (PSAs) are fabricated from soft viscoelastic materials that satisfy Dahlquist's criterion for tack with a Young's modulus (E) of 100 kPa or less at room temperature and 1 Hz. In contrast, the adhesive on the toes of geckos is made of beta-keratin, a stiff material with E at least four orders of magnitude greater than the upper limit of Dahlquist's criterion. Therefore, one would not expect a beta-keratin structure to function as a PSA by deforming readily to make intimate molecular contact with a variety of surface profiles. However, since the gecko adhesive is a microstructure in the form of an array of millions of high aspect ratio shafts (setae), the effective elastic modulus (E(eff)) is much lower than E of bulk beta-keratin. In the first test of the E(eff) of a gecko setal adhesive, we measured the forces resulting from deformation of isolated arrays of tokay gecko (Gekko gecko) setae during vertical compression, and during tangential compression at angles of +45 degrees and -45 degrees . We tested the hypothesis that E(eff) of gecko setae falls within Dahlquist's criterion for tack, and evaluated the validity of a model of setae as cantilever beams. Highly linear forces of deformation under all compression conditions support the cantilever model. E(eff) of setal arrays during vertical and +45 degrees compression (along the natural path of drag of the setae) were 83+/-4.0 kPa and 86+/-4.4 kPa (means +/- s.e.m.), respectively. Consistent with the predictions of the cantilever model, setae became significantly stiffer when compressed against the natural path of drag: E(eff) during -45 degrees compression was 110+/-4.7 kPa. Unlike synthetic PSAs, setal arrays act as Hookean elastic solids; setal arrays function as a bed of springs with a directional stiffness, assisting alignment of the adhesive spatular tips with the contact surface during shear loading.

  6. Hydrocephalus due to extreme dilation of Virchow-Robin spaces

    Science.gov (United States)

    Revel, Frederic; Cotton, Francois; Haine, Max; Gilbert, Thomas

    2015-01-01

    Virchow-Robin spaces (VRS) are extensions of the subarachnoid space surrounding perforating blood vessels entering the brain parenchyma. VRS are fluid filled, but almost virtual and only visible on MRI of the brain when dilated. Such dilations are commonly asymptomatic. In rare cases, extreme dilations can be observed; the clinical repercussions of which remain unclear. We report the case of a patient presenting symptoms of normal pressure hydrocephalus due to extreme VRS mesencephalon dilations. PMID:25564639

  7. Low elastic modulus titanium–nickel scaffolds for bone implants

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jing; Yang, Hailin; Wang, Huifeng; Ruan, Jianming, E-mail: jianming@csu.edu.cn

    2014-01-01

    The superelastic nature of repeating the human bones is crucial to the ideal artificial biomedical implants to ensure smooth load transfer and foster the ingrowth of new bone tissues. Three dimensional interconnected porous TiNi scaffolds, which have the tailorable porous structures with micro-hole, were fabricated by slurry immersing with polymer sponge and sintering method. The crystallinity and phase composition of scaffolds were studied by X-ray diffraction. The pore morphology, size and distribution in the scaffolds were characterized by scanning electron microscopy. The porosity ranged from 65 to 72%, pore size was 250–500 μm. Compressive strength and elastic modulus of the scaffolds were ∼ 73 MPa and ∼ 3GPa respectively. The above pore structural and mechanical properties are similar to those of cancellous bone. In the initial cell culture test, osteoblasts adhered well to the scaffold surface during a short time, and then grew smoothly into the interconnected pore channels. These results indicate that the porous TiNi scaffolds fabricated by this method could be bone substitute materials. - Highlights: • A novel approach for the fabrication of porous TiNi scaffolds • Macroporous structures are replicated from the polymer sponge template. • The pore characteristics and mechanical properties of TiNi scaffolds agree well with the requirement of trabecular bone. • Cytocompatibility of TiNi scaffolds is assessed, and it closely associated with pore property.

  8. Determining the Young's modulus of a cellular titanium implant by FEM simulation

    Science.gov (United States)

    Loginov, Yu. N.; Golodnov, A. I.; Stepanov, S. I.; Kovalev, E. Yu.

    2017-12-01

    The role of additive manufacturing is noted for the construction of titanium medical implants. The purpose of the study is to determine the Young's modulus of cellular titanium implants, which is based on calculations performed by finite element analysis. A honeycomb structure from intersecting cylinder surfaces is offered for the implant made of the Ti-6Al-4V alloy. Boundary conditions are stated for the loading of the implant structure. It is demonstrated that the Young's modulus can be reduced more than three times comparing to a solid titanium alloy. Zones of strain and stress localization located near the abutment of the cylindrical surfaces. Recommendations for the further improvement of the implant architecture are generated.

  9. Cosmic time dilation: The clock paradox revisited

    International Nuclear Information System (INIS)

    Tomaschitz, Roman

    2004-01-01

    The relativistic time dilation is reviewed in a cosmological context. We show that a clock or twin paradox does not arise if cosmic time is properly taken into account. The receding galaxy background provides a unique frame of reference, and the proper times of geodesic as well as accelerated observers can be linked to the universal cosmic time parameter. This suggests to compare the proper time differentials of the respective observers by determining their state of motion in the galaxy grid. In this way, each observer can figure out whether his proper time is dilated or contracted relative to any other. In particular one can come to unambiguous conclusions on the aging of uniformly moving observers, without reference to asymmetries in measurement procedures or accelerations they may have undergone

  10. Estimate of K-functionals and modulus of smoothness constructed ...

    Indian Academy of Sciences (India)

    2016-08-26

    functional and a modulus of smoothness for the Dunkl transform on Rd. Author Affiliations. M El Hamma1 R Daher1. Department of Mathematics, Faculty of Sciences Aïn Chock, University of Hassan II, Casablanca, Morocco. Dates.

  11. Standardizing lightweight deflectometer modulus measurements for compaction quality assurance

    Science.gov (United States)

    2017-09-01

    To evaluate the compaction of unbound geomaterials under unsaturated conditions and replace the conventional methods with a practical modulus-based specification using LWD, this study examined three different LWDs, the Zorn ZFG 3000 LWD, Dynatest 303...

  12. Estimation of subgrade resilient modulus using the unconfined compression test.

    Science.gov (United States)

    2014-11-01

    To facilitate pavement design, the new proposed mechanistic-empirical pavement design guide recommends the resilient : modulus to characterize subgrade soil and its use for calculating pavement responses attributable to traffic and environmental : lo...

  13. Frequency-dependent complex modulus of the uterus: preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Kiss, Miklos Z [Department of Medical Physics, University of Wisconsin, Madison, WI 53706 (United States); Hobson, Maritza A [Department of Medical Physics, University of Wisconsin, Madison, WI 53706 (United States); Varghese, Tomy [Department of Medical Physics, University of Wisconsin, Madison, WI 53706 (United States); Harter, Josephine [Department of Surgical Pathology, University of Wisconsin, Madison, WI 53706 (United States); Kliewer, Mark A [Department of Radiology, University of Wisconsin, Madison, WI 53706 (United States); Hartenbach, Ellen M [Department of Obstetrics and Gynecology, University of Wisconsin, Madison, WI 53706 (United States); Zagzebski, James A [Department of Medical Physics, University of Wisconsin, Madison, WI 53706 (United States)

    2006-08-07

    The frequency-dependent complex moduli of human uterine tissue have been characterized. Quantification of the modulus is required for developing uterine ultrasound elastography as a viable imaging modality for diagnosing and monitoring causes for abnormal uterine bleeding and enlargement, as well assessing the integrity of uterine and cervical tissue. The complex modulus was measured in samples from hysterectomies of 24 patients ranging in age from 31 to 79 years. Measurements were done under small compressions of either 1 or 2%, at low pre-compression values (either 1 or 2%), and over a frequency range of 0.1-100 Hz. Modulus values of cervical tissue monotonically increased from approximately 30-90 kPa over the frequency range. Normal uterine tissue possessed modulus values over the same range, while leiomyomas, or uterine fibroids, exhibited values ranging from approximately 60-220 kPa.

  14. Arithmetic convergent sequence space defined by modulus function

    Directory of Open Access Journals (Sweden)

    Taja Yaying

    2019-10-01

    Full Text Available The aim of this article is to introduce the sequence spaces $AC(f$ and $AS(f$ using arithmetic convergence and modulus function, and study algebraic and topological properties of this space, and certain inclusion results.

  15. Resilient Modulus Characterization of Alaskan Granular Base Materials

    Science.gov (United States)

    2010-08-01

    Resilient modulus (MR) of base course material is an important material input for : pavement design. In Alaska, due to distinctiveness of local climate, material source, : fines content and groundwater level, resilient properties of D-1 granular base...

  16. Cosmological Time Dilation in Gamma Ray Bursts?

    OpenAIRE

    Band, David

    1994-01-01

    Norris et al. (1994) report that the temporal structure of faint gamma ray bursts is longer than that of bright bursts, as expected for time dilation in the cosmological models of burst origin. I show that the observed trends can easily be produced by a burst luminosity function and thus may not result from cosmological effects. A cosmological signature may be present, but the tests Norris et al. present are not powerful enough to detect these signatures.

  17. The Naimark dilated PT-symmetric brachistochrone

    OpenAIRE

    Guenther, Uwe; Samsonov, Boris F.

    2008-01-01

    The quantum mechanical brachistochrone system with PT-symmetric Hamiltonian is Naimark dilated and reinterpreted as subsystem of a Hermitian system in a higher-dimensional Hilbert space. This opens a way to a direct experimental implementation of the recently hypothesized PT-symmetric ultra-fast brachistochrone regime of [C. M. Bender et al, Phys. Rev. Lett. {\\bf 98}, 040403 (2007)] in an entangled two-spin system.

  18. Naimark-Dilated PT-Symmetric Brachistochrone

    Science.gov (United States)

    Günther, Uwe; Samsonov, Boris F.

    2008-12-01

    The quantum mechanical brachistochrone system with a PT-symmetric Hamiltonian is Naimark-dilated and reinterpreted as a subsystem of a Hermitian system in a higher-dimensional Hilbert space. This opens a way to a direct experimental implementation of the recently hypothesized PT-symmetric ultrafast brachistochrone regime of Bender et al. [Phys. Rev. Lett. 98, 040403 (2007)PRLTAO0031-900710.1103/PhysRevLett.98.040403] in an entangled two-spin system.

  19. Stability of wavelet frames with matrix dilations

    DEFF Research Database (Denmark)

    Christensen, Ole; Sun, Wenchang

    2006-01-01

    Under certain assumptions we show that a wavelet frame {Tau(A(j), b(j,k))psi} (j,k is an element of Z) := {vertical bar detA(j)vertical bar(-1/2) psi(A(j)(-1)(x - b(j,k)))} (j,k is an element of Z) in L-2(R-d) remains a frame when the dilation matrices A(j) and the translation parameters b...

  20. CT in thrombosed dilated posterior epidural vein

    Energy Technology Data Exchange (ETDEWEB)

    Bammatter, S.; Schnyder, P.; Preux, J. de

    1987-05-01

    The authors report a case of thrombosis of the distal end of an enlarged right posterior epidural vein. The patient had a markedly narrow lumbar canal due to L5 spondylolisthesis. The dilated vein and the thrombosis were displayed by computed tomography but remained unrecognized until surgery. Pathogenesis of this condition is discussed. A review of the English, French and German literature revealed no prior radiological reports of a similar condition.

  1. Balloon catheter dilatation of benign urethral strictures

    International Nuclear Information System (INIS)

    Perini, L.; Cavallo, A.; Perin, B.; Bighi, G.

    1988-01-01

    The authors report their experience of benign urethral stricture dilatation by balloon catheter in 11 male patients. Ten posterior and 2 anterior urethral strictures were treated; in 1 patients several narrowings coexisted at various levels. Etiology was inflammatory in 4 cases, iatrogen in 3, post-traumatic in 2, and equivocal in 2. The patients were studied both before and soon after dilatation by means of retrograde and voiding cystourethrogram and uroflowgraphy; the follow-up (2-14 months) was performed by urodynamic alone. In all cases, dilatation was followed by the restoration of urethral gauge, together with prompt functional improvement of urodynamic parameters. The latter result subsisted in time in 9 patients. In 2 cases recurrences were observed demonstrated at once by clinics and urodynamics. Both lesions were successfully re-treated. Neither early not late complication occurred. In spite of the limited material, the valuable results obtained, together with the absence of complications, the peculiar morphology of recurrences, and the chance of repeating it make the procedure advisable as a valid alternative to conventional techniques for these pathologies

  2. Time dilation in quantum systems and decoherence

    Science.gov (United States)

    Pikovski, Igor; Zych, Magdalena; Costa, Fabio; Brukner, Časlav

    2017-02-01

    Both quantum mechanics and general relativity are based on principles that defy our daily intuitions, such as time dilation, quantum interference and entanglement. Because the regimes where the two theories are typically tested are widely separated, their foundational principles are rarely jointly studied. Recent works have found that novel phenomena appear for quantum particles with an internal structure in the presence of time dilation, which can take place at low energies and in weak gravitational fields. Here we briefly review the effects of time dilation on quantum interference and generalize the results to a variety of systems. In addition, we provide an extended study of the basic principles of quantum theory and relativity that are of relevance for the effects and also address several questions that have been raised, such as the description in different reference frames, the role of the equivalence principle and the effective irreversibility of the decoherence. The manuscript clarifies some of the counterintuitive aspects arising when quantum phenomena and general relativistic effects are jointly considered.

  3. Time dilation in quantum systems and decoherence

    International Nuclear Information System (INIS)

    Pikovski, Igor; Zych, Magdalena; Costa, Fabio; Brukner, Časlav

    2017-01-01

    Both quantum mechanics and general relativity are based on principles that defy our daily intuitions, such as time dilation, quantum interference and entanglement. Because the regimes where the two theories are typically tested are widely separated, their foundational principles are rarely jointly studied. Recent works have found that novel phenomena appear for quantum particles with an internal structure in the presence of time dilation, which can take place at low energies and in weak gravitational fields. Here we briefly review the effects of time dilation on quantum interference and generalize the results to a variety of systems. In addition, we provide an extended study of the basic principles of quantum theory and relativity that are of relevance for the effects and also address several questions that have been raised, such as the description in different reference frames, the role of the equivalence principle and the effective irreversibility of the decoherence. The manuscript clarifies some of the counterintuitive aspects arising when quantum phenomena and general relativistic effects are jointly considered. (paper)

  4. Coronary dilation with nitrocompounds and calcium antagonists.

    Science.gov (United States)

    Jost, S; Rafflenbeul, W; Lichtlen, P R

    1990-01-01

    The vasodilatory effects of nitrocompounds and calcium antagonists on epicardial coronary arteries represent substantial antianginal mechanisms in the presence of coronary vasospasm or eccentric coronary stenoses. With high doses of nitrocompounds, angiographically normal coronary segments can be dilated by an average of approx. 30%, some coronary stenoses even by up to 100%, usually without severe reduction of blood pressure. With calcium antagonists, a similar extent of dilation of normal coronary arteries and eccentric stenoses can be obtained. Our own group demonstrated an average dilation of normal coronary arteries of about 20% after intravenous administration of dihydropyridine calcium antagonists; however, the average systolic blood pressure dropped below 100 mmHg after these compounds. Hence, although in isolated human coronary arteries high concentrations of calcium antagonists were shown to induce a considerably greater vasodilation than nitrocompounds, the early drop in blood pressure prohibits a higher dosage of calcium antagonists in vivo. In the presence of coronary artery disease, particularly when associated with coronary vasospasm, a combination of the two groups of compounds might be recommendable, since an addition of the effects of coronary vasomotor tone is likely. Furthermore, the antianginal effects of a reduction of preload and afterload are complementary.

  5. VALIDATION OF SMURF ESTIMATION OF SHEAR MODULUS IN HYDROGELS

    OpenAIRE

    MCALEAVEY, STEPHEN; COLLINS, ERIN; KELLY, JOHANNA; ELEGBE, ETANA; MENON, MANOJ

    2009-01-01

    A validation study of the Spatially Modulated Ultrasound Radiation Force (SMURF) method for shear modulus estimation is presented. SMURF estimates of uniform gelatin and Zerdine™ phantoms covering a modulus range of 2 to 18 kPa are compared with results obtained by unconfined mechanical compression and sonoelastography. The results show agreement within the measurement uncertainties over the range indicated for all three methods. Repeatability and variation on the order of 5% of the phantom m...

  6. Shrinkage, stress, and modulus of dimethacrylate, ormocer, and silorane composites.

    Science.gov (United States)

    Bacchi, Atais; Feitosa, Victor Pinheiro; da Silva Fonseca, Andrea Soares Quirino; Cavalcante, Larissa Maria Assad; Silikas, Nikolaos; Schneider, Luis Felipe Jochins

    2015-01-01

    to evaluate the shrinkage, polymerization stress, elastic and bulk modulus resulting from composites formulated by siloranes, 2(nd) generation ormocers, and dimethacrylates. The bonded disc method was used to evaluate volumetric shrinkage. The polymerization stress was evaluated by mean of the Bioman. Cylindrical specimens (5 mm thickness and 6 mm diameter) were submitted to gradual loading. Young's and bulk modulus were obtained from the slope of the stress/strain curve. Data were analyzed using one-way analysis of variance and Tukey's test (5%). Grandio and ormocer showed significant higher elastic and bulk modulus. Silorane presented significant lowest bulk modulus and maximum shrinkage. Ormocer and silorane presented lower values for the maximum rate of shrinkage. Extra-low shrinkage (ELS) composite presented the greatest maximum shrinkage. The higher maximum rate of shrinkage was attained by Grandio and ELS, statistically similar from each other. The silorane showed lower values of maximum stress and maximum rate of stress. The higher values of maximum stress were presented by ELS and Grandio, statistical similar between them. Grandio showed the significantly greatest maximum rate of stress. Silorane showed to promote lower shrinkage/stress among the composites, with the lowest elastic modulus. Ormocer showed lower shrinkage/stress than methacrylates despite of its high modulus.

  7. Non-toxic invert analog glass compositions of high modulus

    Science.gov (United States)

    Bacon, J. F. (Inventor)

    1974-01-01

    Glass compositions having a Young's modulus of at least 15 million psi are described. They and a specific modulus of at least 110 million inches consist essentially of, in mols, 15 to 40% SiO2, 6 to 15% Li2O, 24 to 45% of at least two bivalent oxides selected from the group consisting of Ca, NzO, MgO and CuO; 13 to 39% of at least two trivalent oxides selected from the group consisting of Al2O3, Fe2O3, B2O3, La2O3, and Y2O3 and up to 15% of one or more tetravelent oxides selected from the group consisting of ZrO2, TiO2 and CeO2. The high modulus, low density glass compositions contain no toxic elements. The composition, glass density, Young's modulus, and specific modulus for 28 representative glasses are presented. The fiber modulus of five glasses are given.

  8. Validation of SMURF estimation of shear modulus in hydrogels.

    Science.gov (United States)

    McAleavey, Stephen; Collins, Erin; Kelly, Johanna; Elegbe, Etana; Menon, Manoj

    2009-04-01

    A validation study of the Spatially Modulated Ultrasound Radiation Force (SMURF) method for shear modulus estimation is presented. SMURF estimates of uniform gelatin and Zerdine phantoms covering a modulus range of 2 to 18 kPa are compared with results obtained by unconfined mechanical compression and sonoelastography. The results show agreement within the measurement uncertainties over the range indicated for all three methods. Repeatability and variation on the order of 5% of the phantom modulus are found for observations made at a single point within the phantom. Averaging of modulus estimates from several adjacent scan lines further decreases the variation. By using multiple radiation force peaks to induce a shear wave of known wavelength and measure the frequency of the wave, SMURF obtains modulus estimates from tracking data acquired along a single A-line. This is significant, as speckle can bias the measured phase of the shear wave. SMURF is shown to be insensitive to a constant phase error in the shear wave measurement. This results in greatly reduced correlated noise in the modulus estimates, in contrast with methods which track at multiple locations and do not cancel phase errors.

  9. Determination of elastic modulus of ceramics using ultrasonic testing

    Science.gov (United States)

    Sasmita, Firmansyah; Wibisono, Gatot; Judawisastra, Hermawan; Priambodo, Toni Agung

    2018-04-01

    Elastic modulus is important material property on structural ceramics application. However, bending test as a common method for determining this property require particular specimen preparation. Furthermore, elastic modulus of ceramics could vary because it depends on porosity content. For structural ceramics industry, such as ceramic tiles, this property is very important. This drives the development of new method to improve effectivity or verification method as well. In this research, ultrasonic testing was conducted to determine elastic modulus of soda lime glass and ceramic tiles. The experiment parameter was frequency of probe (1, 2, 4 MHz). Characterization of density and porosity were also done for analysis. Results from ultrasonic testing were compared with elastic modulus resulted from bending test. Elastic modulus of soda-lime glass based on ultrasonic testing showed excellent result with error 2.69% for 2 MHz probe relative to bending test result. Testing on red and white ceramic tiles were still contained error up to 41% and 158%, respectively. The results for red ceramic tile showed trend that 1 MHz probe gave better accuracy in determining elastic modulus. However, testing on white ceramic tile showed different trend. It was due to the presence of porosity and near field effect.

  10. Influence of random shrinkage porosity on equivalent elastic modulus of casting: A statistical and numerical approach

    Directory of Open Access Journals (Sweden)

    Wei Liu

    2017-03-01

    Full Text Available Shrinkage porosity is a type of random distribution defects and exists in most large castings. Different from the periodic symmetry defects or certain distribution defects, shrinkage porosity presents a random “cloud-like” configuration, which brings difficulties in quantifying the effective performance of defected casting. In this paper, the influences of random shrinkage porosity on the equivalent elastic modulus of QT400-18 casting were studied by a numerical statistics approach. An improved random algorithm was applied into the lattice model to simulate the “cloud-like” morphology of shrinkage porosity. Then, a large number of numerical samples containing random levels of shrinkage were generated by the proposed algorithm. The stress concentration factor and equivalent elastic modulus of these numerical samples were calculated. Based on a statistical approach, the effects of shrinkage porosity’s distribution characteristics, such as area fraction, shape, and relative location on the casting’s equivalent mechanical properties were discussed respectively. It is shown that the approach with randomly distributed defects has better predictive capabilities than traditional methods. The following conclusions can be drawn from the statistical simulations: (1 the effective modulus decreases remarkably if the shrinkage porosity percent is greater than 1.5%; (2 the average Stress Concentration Factor (SCF produced by shrinkage porosity is about 2.0; (3 the defect’s length across the loading direction plays a more important role in the effective modulus than the length along the loading direction; (4 the surface defect perpendicular to loading direction reduces the mean modulus about 1.5% more than a defect of other position.

  11. Effects of Bone Young’s Modulus on Finite Element Analysis in the Lateral Ankle Biomechanics

    Directory of Open Access Journals (Sweden)

    W. X. Niu

    2013-01-01

    Full Text Available Finite element analysis (FEA is a powerful tool in biomechanics. The mechanical properties of biological tissue used in FEA modeling are mainly from experimental data, which vary greatly and are sometimes uncertain. The purpose of this study was to research how Young’s modulus affects the computations of a foot-ankle FEA model. A computer simulation and an in-vitro experiment were carried out to investigate the effects of incremental Young’s modulus of bone on the stress and strain outcomes in the computational simulation. A precise 3-dimensional finite element model was constructed based on an in-vitro specimen of human foot and ankle. Young’s moduli were assigned as four levels of 7.3, 14.6, 21.9 and 29.2 GPa respectively. The proximal tibia and fibula were completely limited to six degrees of freedom, and the ankle was loaded to inversion 10° and 20° through the calcaneus. Six cadaveric foot-ankle specimens were loaded as same as the finite element model, and strain was measured at two positions of the distal fibula. The bone stress was less affected by assignment of Young’s modulus. With increasing of Young’s modulus, the bone strain decreased linearly. Young’s modulus of 29.2 GPa was advisable to get the satisfactory surface strain results. In the future study, more ideal model should be constructed to represent the nonlinearity, anisotropy and inhomogeneity, as the same time to provide reasonable outputs of the interested parameters.

  12. Variable modulus cellular structures using pneumatic artificial muscles

    Science.gov (United States)

    Pontecorvo, Michael E.; Niemiec, Robert J.; Gandhi, Farhan S.

    2014-04-01

    This paper presents a novel variable modulus cellular structure based on a hexagonal unit cell with pneumatic artificial muscle (PAM) inclusions. The cell considered is pin-jointed, loaded in the horizontal direction, with three PAMs (one vertical PAM and two horizontal PAMs) oriented in an "H" configuration between the vertices of the cell. A method for calculation of the hexagonal cell modulus is introduced, as is an expression for the balance of tensile forces between the horizontal and vertical PAMs. An aluminum hexagonal unit cell is fabricated and simulation of the hexagonal cell with PAM inclusions is then compared to experimental measurement of the unit cell modulus in the horizontal direction with all three muscles pressurized to the same value over a pressure range up to 758 kPa. A change in cell modulus by a factor of 1.33 and a corresponding change in cell angle of 0.41° are demonstrated experimentally. A design study via simulation predicts that differential pressurization of the PAMs up to 2068 kPa can change the cell modulus in the horizontal direction by a factor of 6.83 with a change in cell angle of only 2.75°. Both experiment and simulation show that this concept provides a way to decouple the length change of a PAM from the change in modulus to create a structural unit cell whose in-plane modulus in a given direction can be tuned based on the orientation of PAMs within the cell and the pressure supplied to the individual muscles.

  13. Young’s Modulus and Poisson’s Ratio of Monolayer Graphyne

    Directory of Open Access Journals (Sweden)

    H. Rouhi

    2013-09-01

    Full Text Available Despite its numerous potential applications, two-dimensional monolayer graphyne, a novel form of carbon allotropes with sp and sp2 carbon atoms, has received little attention so far, perhaps as a result of its unknown properties. Especially, determination of the exact values of its elastic properties can pave the way for future studies on this nanostructure. Hence, this article describes a density functional theory (DFT investigation into elastic properties of graphyne including surface Young’s modulus and Poisson’s ratio. The DFT analyses are performed within the framework of generalized gradient approximation (GGA, and the Perdew–Burke–Ernzerhof (PBE exchange correlation is adopted. This study indicates that the elastic modulus of graphyne is approximately half of that of graphene due to its lower number of bonds.

  14. Shear modulus imaging with spatially-modulated ultrasound radiation force.

    Science.gov (United States)

    McAleavey, Stephen; Menon, Manoj; Elegbe, Etana

    2009-10-01

    The application of Spatially-Modulated Ultrasound Radiation Force (SMURF) to shear modulus imaging is demonstrated in tissue-mimicking phantoms and porcine liver. Scanning and data acquisition was performed with a Siemens Antares ultrasound scanner and VF7-3 linear array operating at 4.21 MHz. Modulus estimates in uniform phantoms of Zerdine with shear moduli of 5.1 and 12.4 kPa exhibited standard deviations within 6% of the mean value. Zerdine spheres 1 cm in diameter (nominally 2.7, 4.7 and 15 kPa) in a 8 kPa (nominal) background are clearly resolved. Cross sectional images of a soft conical inclusion in a gelatin-based phantom indicate a spatial resolution of approximately 2.5 mm. Images of the shear modulus of an ex-vivo sample of porcine liver tissue show an average value of 3 kPa. A stifflesion induced with 0.5 mL of 10% glutaraldehyde is clearly visible as a region of shear modulus in excess of 10 kPa. A modulus gradient associated with the diffusion of the glutaraldehyde is visible. Two pulse sequences were examined, differing only in the timing of the beams used to generate the shear waves. Details of the beam sequences and subsequent signal processing are presented.

  15. Shear Modulus Imaging with Spatially Modulated Ultrasound Radiation Force

    Science.gov (United States)

    McAleavey, Stephen; Menon, Manoj; Elegbe, Etana

    2011-01-01

    The application of Spatially Modulated Ultrasound Radiation Force (SMURF) to shear modulus imaging is demonstrated in tissue mimicking phantoms and porcine liver. Scanning and data acquisition was performed with a Siemens Antares ultrasound scanner and VF7-3 linear array operating at 4.21 MHz. Modulus estimates in uniform phantoms of Zerdine™ with shear moduli of 5.1 and 12.4 kPa exhibited standard deviations within 6% of the mean value. Zerdine spheres 1 cm in diameter (nominally 2.7, 4.7, and 15 kPa) in a 8 kPa (nominal) background are clearly resolved. Cross sectional images of a soft conical inclusion in a gelatin-based phantom indicate a spatial resolution of approximately 2.5 mm. Images of the shear modulus of an ex-vivo sample of porcine liver tissue show an average value of 3kPa. A stiff lesion induced with 0.5 mL of 10% glutaraldehyde is clearly visible as a region of shear modulus in excess of 10 kPa. A modulus gradient associated with the diffusion of the glutaraldehyde is visible. Two pulse sequences were examined, differing only in the timing of the beams used to generate the shear waves. Details of the beam sequences and subsequent signal processing are presented. PMID:20458875

  16. Method for in-situ nondestructive measurement of Young's modulus of plate structures

    Science.gov (United States)

    Huang, Jerry Qixin (Inventor); Perez, Robert J. (Inventor); DeLangis, Leo M. (Inventor)

    2003-01-01

    A method for determining stiffness of a composite laminate plate entails disposing a device for generating an acoustical pulse against a surface of the plate and disposing a detecting device against the same surface spaced a known distance from the pulse-generating device, and using the pulse-generating device to emit a pulse so as to create an extensional wave in the plate. The detecting device is used to determine a time of flight of the wave over the known distance, and the wave velocity is calculated. A Young's modulus of the plate is determined based on the wave velocity. Methods for both anisotropic and quasi-isotropic laminates are disclosed.

  17. The neural substrates of subjective time dilation

    OpenAIRE

    Marc Wittmann; Marc Wittmann; Marc Wittmann; Virginie Van Wassenhove; Bud Craig; Martin P Paulus; Martin P Paulus

    2010-01-01

    An object moving towards an observer is subjectively perceived as longer in duration than the same object that is static or moving away. This 'time dilation effect' has been shown for a number of stimuli that differ from standard events along different feature dimensions (e.g. color, size, and dynamics). We performed an event-related functional magnetic resonance imaging (fMRI), while subjects viewed a stream of five visual events, all of which were static and of identical duration except the...

  18. The Neural Substrates of Subjective Time Dilation

    OpenAIRE

    Wittmann, Marc; van Wassenhove, Virginie; Craig, A. D. (Bud); Paulus, Martin P.

    2010-01-01

    An object moving towards an observer is subjectively perceived as longer in duration than the same object that is static or moving away. This ”time dilation effect” has been shown for a number of stimuli that differ from standard events along different feature dimensions (e.g. color, size, and dynamics). We performed an event-related functional magnetic resonance imaging (fMRI) study, while subjects viewed a stream of five visual events, all of which were static and of identical duration exce...

  19. Dilated cardiomyopathy following use of xenadrine EFX

    Science.gov (United States)

    Riccioni, Graziano; Speziale, Giuseppe; Scotti, Luca; Bucciarelli, Valentina; Cappetti, Silvia; Nasso, Giuseppe; Gallina, Sabina; Bucciarelli, Tonino

    2015-01-01

    We describe a case of a 35-year-old man presented at the emergency room of our institution with acute onset of dyspnea and dizziness. He was a body builder and had been using Xenadrine EFX for weight loss reduction. The laboratory analyses were normal. A chest radiograph showed an enlarged cardiac silhouette with clear lung fields. Transtoracic two-dimensional color Doppler echocardiography revealed a diffuse hypokinesia with a marked decreased in systolic function and a high teledyastolic diameter. This case document the possible relation to use of Xenadrine EFX for weight loss and the recurrence of dilated cardiomyopathy. PMID:26680256

  20. Determination of Young's Modulus of Graphene by Raman Spectroscopy

    Science.gov (United States)

    Lee, Jae-Ung; Yoon, Duhee; Cheong, Hyeonsik

    2012-02-01

    The mechanical properties of graphene are interesting research subjects because its Young's modulus and strength are extremely high. Values of ˜1 TPa for the Young's modulus have been reported [Lee et al. Science, 321, 385 (2008), Koenig et al. Nat. Nanotech. 6, 543 (2011)]. We made a graphene sample on a SiO2/Si substrate with closed-bottom holes by mechanical exfoliation. A pressure difference across the graphene membrane was applied by putting the sample in a vacuum chamber. This pressure difference makes the graphene membrane bulge upward like a balloon. By measuring the shifts of the Raman G and 2D bands, we estimated the amount of strain on the graphene membrane. By comparing the strain estimated from the Raman measurements with numerical simulations based on the finite element method, we obtained the Young's modulus of graphene.

  1. Thermophysical Analysis of High Modulus Composite Materials for Space Vehicles

    Science.gov (United States)

    Lee, Ho-Sung

    2009-01-01

    High modulus composite materials are used extensively in aerospace vehicles mainly for the purpose of increasing strength and reducing weight. However, thermal properties have become essential design information with the use of composite materials in the thermal design of spacecraft and spacecraft electronics packages. This is because the localized heat from closely packed devices can lead to functional failure of the aerospace system unless the heat is dissipated. In this study, thermal responses of high modulus advanced materials are considered for aerospace thermal design. The advanced composite material is composed of a continuous high modulus pitch based fiber and epoxy resin. In order to compare this advanced composite material with conventional aerospace composite materials, the thermophysical analysis of both materials was performed. The results include thermal conductivity measurements of composite materials and various thermal analytical techniques with DSC, TGA, TMA and DMA.

  2. Percutaneous Dilatational Tracheostomy via Griggs Technique.

    Science.gov (United States)

    Karimpour, Hasan Ali; Vafaii, Kamran; Chalechale, Maryam; Mohammadi, Saeed; Kaviannezhad, Rasool

    2017-01-01

    Tracheostomy is considered the airway management of choice for patients who need prolonged mechanical ventilation support. Percutaneous Dilatational Tracheotomy (PDT) is a technique that can be performed easily and rapidly at bedside and is particularly useful in the intensive care setting. The Griggs percutaneous tracheotomy is unique in its utilization of a guide wire dilator forceps. We aimed to describe the early perioperative and late postoperative complications of PDT using the Griggs technique in patients in the intensive care unit (ICU). This cross-sectional study was conducted on all patients who underwent tracheostomy in the ICU of the Imam Reza Hospital of Kermanshah, Iran, from June 2011 to June 2015. PDT was performed in 184 patients with the Griggs technique. Demographic variables, as well as perioperative and late postoperative complications were recorded. The mean age of patients was 57.3 ± 15.37 years. The most common primary causes of tracheostomy were hypoxic brain damage disorders (43.2%) and pneumonia (14.8%). Perioperative and early complications occurred in 16.7 % of procedures, of which 9.3% were bleedings (minor, significant and major). Furthermore, the incidence of late complications was 8.6%, including: stomal infection, difficult replace tracheostomy tube, tracheoesophageal fistula, tracheal stenosis, and tracheomalacia. PDT via Griggs technique is a safe, quick, and effective method. The low incidence of complications indicates that bedside percutaneous tracheostomy can be performed safely as a routine procedure for daily care implemented in the ICU.

  3. Gastric Dilation and Volvulus Syndrome in Dog

    Directory of Open Access Journals (Sweden)

    Ami S. Bhatia

    Full Text Available Gastric dilatation and volvulus syndrome (GDV in dogs is an abnormal accumulation of gastric gas (dilatation, which may be complicated by rotation of the stomach (volvulus about its mesentric axis. A number of factors, both environmental and host have been implicated in GDV. This syndrome has a variety of effects on the cardiovascular, respiratory, gastrointestinal, metabolic, haemolymphatic-immune, renal and central nervous systems. Clinical signs include distended, painful, tympanic abdomen, retching, unproductive vomiting, hypersalivation, respiratory distress accompanied by varying degrees of shock. Treatment of GDV includes medical and fluid therapy at shock dosages to initially stabilize the patient followed by gastric decompression. Surgical procedure comprises of gastric derotation followed by partial gastrectomy or spleenectomy depending upon gastric or spleenic viability and lastly, permanent right sided gastropexy. Post surgical considerations include frequent small meals instead of one large meal, avoiding vigorous activity immediately after meals and not allowing animal to gorge on water after meals or activities. [Veterinary World 2010; 3(12.000: 554-557

  4. Shear Modulus Imaging with Spatially Modulated Ultrasound Radiation Force

    OpenAIRE

    McAleavey, Stephen; Menon, Manoj; Elegbe, Etana

    2009-01-01

    The application of Spatially Modulated Ultrasound Radiation Force (SMURF) to shear modulus imaging is demonstrated in tissue mimicking phantoms and porcine liver. Scanning and data acquisition was performed with a Siemens Antares ultrasound scanner and VF7-3 linear array operating at 4.21 MHz. Modulus estimates in uniform phantoms of Zerdine™ with shear moduli of 5.1 and 12.4 kPa exhibited standard deviations within 6% of the mean value. Zerdine spheres 1 cm in diameter (nominally 2.7, 4.7, a...

  5. Isentropic Bulk Modulus: Development of a Federal Test Method

    Science.gov (United States)

    2016-01-01

    bulk modulus space from synthetic iso -paraffinic fuels to petroleum-based diesel fuels. The test fuels are identified in Table 1. A testing order and...10 20 30 40 50 60 70 80 0 2 4 6 8 10 12 14 16 Pressure (psi) Thousands Speed -of-Sound (m/s) r R 0 5000 10000 15000 20000 25000 30000 35000 0 2 4 6 8...Thousands Speed -of-Sound (m/s) r R 0 5000 10000 15000 20000 25000 30000 35000 0 2 4 6 8 10 12 14 16 Pressure (psi) Thousands Bulk Modulus (psi) r R

  6. Temperature, Frequency and Young’s Modulus of a Wineglass

    Directory of Open Access Journals (Sweden)

    Amitta Miller

    2015-01-01

    Full Text Available A crystal soda-lime wineglass, heated to temperatures ranging from 25 °C to 150 °C, was tapped and the frequency recorded. It was shown that the relative change in the frequency at different temperatures can be used to determine the effect of temperature on Young’s Modulus of the glass. This simple method of tapping a wineglass is proposed as an effective way of determining the relative effect of temperature on Young’ Modulus of glass.

  7. Roentgenoendovascular dilatation and recanalization of vessels of lower extremities

    International Nuclear Information System (INIS)

    Rabkin, I.Kh.; Matevosov, A.L.; Gotman, L.N.

    1987-01-01

    Advantages and disadvantages of using roentgenoendovascular dilatation (RED) of vessels of lower extremities are presented. RED is recommended in treating patients with short segmented stenoses of common and external illiac arteries and also with the similar damages of surficial femoral arteries. Dilatation is a success when there is permeability in at least one of the three central crus arteries. Success of delayed results of vessel dilatation is to a certain degree in inverse proportion to time and length of occlusion

  8. Indentation modulus and hardness of viscoelastic thin films by atomic force microscopy: A case study

    Energy Technology Data Exchange (ETDEWEB)

    Passeri, D., E-mail: daniele.passeri@uniroma1.it [Dipartimento di Energetica, Universita di Roma ' La Sapienza' , Via A. Scarpa 16, 00161 Roma (Italy); Bettucci, A.; Biagioni, A.; Rossi, M.; Alippi, A. [Dipartimento di Energetica, Universita di Roma ' La Sapienza' , Via A. Scarpa 16, 00161 Roma (Italy); Tamburri, E. [Dipartimento di Scienze e Tecnologie Chimiche, Universita di Roma ' Tor Vergata' , Via della Ricerca Scientifica, 00133 Roma (Italy); Lucci, M.; Davoli, I. [Dipartimento di Fisica, Universita di Roma ' Tor Vergata' , Via della Ricerca Scientifica, 00133 Roma (Italy); Berezina, S. [Department of Physics, University of Zilina, 01026, Univerzitna 1 Zilina (Slovakia)

    2009-11-15

    We propose a nanoindentation technique based on atomic force microscopy (AFM) that allows one to deduce both indentation modulus and hardness of viscoelastic materials from the force versus penetration depth dependence, obtained by recording the AFM cantilever deflection as a function of the sample vertical displacement when the tip is pressed against (loading phase) and then removed from (unloading phase) the surface of the sample. Reliable quantitative measurements of both indentation modulus and hardness of the investigated sample are obtained by calibrating the technique through a set of different polymeric samples, used as reference materials, whose mechanical properties have been previously determined by standard indentation tests. By analyzing the dependence of the cantilever deflection versus time, the proposed technique allows one to evaluate and correct the effect of viscoelastic properties of the investigated materials, by adapting a post-experiment data processing procedure well-established for standard depth sensing indentation tests. The technique is described in the case of the measurement of indentation modulus and hardness of a thin film of poly(3,4-ethylenedioxythiophene) doped with poly(4-styrenesulfonate), deposited by chronoamperometry on an indium tin oxide (ITO) substrate.

  9. Nano-fillers to tune Young’s modulus of silicone matrix

    International Nuclear Information System (INIS)

    Xia Lijin; Xu Zhonghua; Sun Leming; Caveney, Patrick M.; Zhang Mingjun

    2013-01-01

    In this study, we investigated nanoparticles, nanofibers, and nanoclays for their filler effects on tuning the Young’s modulus of silicone matrix, a material with broad in vivo applications. Nano-fillers with different shapes, sizes, and surface properties were added into silicone matrix, and then their filler effects were evaluated through experimental studies. It was found that spherical nanoparticles could clearly improve Young’s modulus of the silicone matrix, while nanoclays and carbon nanofibers had limited effects. Smaller spherical nanoparticles were better in performance compared to larger nanoparticles. In addition, enhanced distribution of the nanoparticles in the matrix has been observed to improve the filler effect. In order to minimize toxicity of the nanoparticles for in vivo applications, spherical nanoparticles coated with amine, acid, or hydroxide groups were also investigated, but they were found only to diminish the filler effect of nanoparticles. This study demonstrated that spherical nanoparticles could serve as fillers to tune Young’s modulus of silicone matrix for potential applications in medicine.

  10. Sand production prediction using ratio of shear modulus to bulk compressibility (case study

    Directory of Open Access Journals (Sweden)

    Ehsan Khamehchi

    2015-06-01

    Full Text Available Sand production is a serious problem widely existing in oil/gas production. The problems resulting from sand influx include abrasion of downhole tubular/casing, subsurface safety valve and surface equipment; casing/tubing buckling, failure of casing or liners from removal of surrounding formation, compaction and erosion; and loss of production caused by sand bridging in tubing and/or flow lines. There are several methods for predicting sand production. The methods include use of production data, well logs, laboratory testing, acoustic, intrusive sand monitoring devices, and analogy. The methodologies are reviewed and the data needed for predicting sand production are enumerated. The technique used in this paper involves the calculation of shear modulus, bulk compressibility, and the ratio of shear modulus to bulk compressibility. The shear modulus to bulk compressibility ratio has been related empirically to sand influx. This Mechanical Properties Log method works 81% of the time. This technique is supported with examples and case studies from regions around the world known for sand production. The authors collected the information of the “Kaki and Bushgan Oilfield in Iran”, set a sand production prediction to predict sand production potential. The technique has been successfully applied in reservoirs and results have been compared with testing data.

  11. A Comparative Study of Solutions Concerning Thick Elastic Plates on Bi-modulus Foundation

    Directory of Open Access Journals (Sweden)

    Ioana Vlad

    2004-01-01

    Full Text Available The classical bending theory of elastic plates is based upon the assumption that the internal moments are proportional to the curvatures of the median deformed surface. This theory does not include the effects of shear and normal pressure in the plate. The model of a bi-modulus foundation is a realistic generalization of the Winkler’s classical one and is widely used to represent the subgrade of railroad systems, airport lanes [1], [2]. The derived equation of elastic thick plates on bi-modulus foundation considers shear and normal stress as linear variable across the plate thickness. This paper presents numerical solutions for thick plate resting on bi-modulus subgrade. These solutions take into account the shear distortion, and they are compared to the solution obtained by Finite Element Analysis and with the Winkler’s model. Particular solutions for the rectangular plate of clamped boundary, for the hinged rectangular plate and for a semi-elliptical plate, are discussed. The numerical solutions consist of double power series and they were obtained based on the minimum of the total strain energy [1]. Parametric studies have been performed in order to emphasize the effects of the chosen foundation and that of the geometry.

  12. Choanal Atresia: Surgical Management by Hegar's Dilators.

    Science.gov (United States)

    Sinha, Vikas; Gurnani, Deepanshu; Modi, Niral R; Barot, Dilavar A; Maniyar, Hiten R; Pandey, Ambuj

    2014-09-01

    Choanal atresia is one of the more commonly observed congenital abnormalities of the nose. The condition is predominantly found in females with a M:F ratio of 1:2. 65-75 % of patients with choanal atresia are unilateral, and the rest are bilateral. About 50 % of the cases are associated with other congenital anomalies, the most common being coloboma, Heart disease, choanal atresia, mental and growth retardation, genital hypoplasia, ear deformities syndrome. The embryonic origin of choanal atresia is due to persistent bucco-pharyngeal or naso-buccal membrane. Our study was a retrospective study of 14 cases of choanal atresia. All the cases were operated by the first author. Each patient was investigated in detail and recorded by stratifying in sex of patient, age of presentation, type and site of atresia, and associated other congenital anomalies. Patient were operated under general anesthesia and Hegar's dilators were used to perforate the atretic plate as Hegar's dilators are believed to have ideal curvature with respect to the sloping contour of the nasal floor. Out of the total 14 cases, 9 (64 %, n = 14) cases were male and 5 (36 %, n = 14) females. The age variations varied from youngest of 3 days to the oldest 31 year old female. Stents were kept for a period of 6-8 weeks and regular follow up nasal endoscopy was done weekly for suctioning and visualizing the size of the airway. There are five different surgical approaches that have been described for surgical treatment of choanal atresia: (1) trans-nasal, (2) trans-palatal, (3) trans-septal, (4) trans-antral and (5) sublabial-transnasal. In our study M:F ratio was 1.8:1 which is comparable Gosepath et al. (Rhinology 45:158-163, 2007) (2:1). In our study bilateral atresia was seen in 43 % (6, n = 14) and unilateral in 57 % (8, n = 14) which is comparable to Newman et al. (44 % bilateral cases, n = 43). Amicable and prompt referral to the ENT surgeon can be of immense value so as to buy

  13. Estimate of K-functionals and modulus of smoothness constructed ...

    Indian Academy of Sciences (India)

    Indian Acad. Sci. (Math. Sci.) Vol. 124, No. 2, May 2014, pp. 235–242. c Indian Academy of Sciences. Estimate of K-functionals and modulus of smoothness constructed by generalized spherical mean operator. M EL HAMMA and R DAHER. Department of Mathematics, Faculty of Sciences Aïn Chock, University of Hassan II,.

  14. The Evaluation Of Deformability Modulus By Rock Mass ...

    African Journals Online (AJOL)

    The Evaluation Of Deformability Modulus By Rock Mass Classification Systems: A Comparative Study. ... Journal of Civil Engineering Research and Practice ... The systems of classification of rock mass give, apart from useful qualitative and quantitative indications about the problems connected to the excavation of tunnels ...

  15. Device to measure elastic modulus of superconducting windings

    CERN Multimedia

    CERN PhotoLab

    1979-01-01

    This device was made to measure elastic modulus of the Po dipole superconducting coils. More elaborated devices, but based on the same concept, were later used to measure the apparent elastic moduli of the LHC superconducting magnet coils. See also 7903547X, 7901386.

  16. Device for measuring elastic modulus of superconducting coils (See 7903169)

    CERN Multimedia

    1979-01-01

    This device was made to measure elastic modulus of the Po dipole superconducting coils. More elaborated devices, but based on the same concept, were later used to measure the apparent elastic moduli of the LHC superconducting magnet coils. See also 7903169, 7901386.

  17. Modulus of smoothness and theorems concerning approximation on compact groups

    Directory of Open Access Journals (Sweden)

    H. Vaezi

    2003-01-01

    Full Text Available We consider the generalized shift operator defined by (Shuf(g=∫Gf(tut−1gdt on a compact group G, and by using this operator, we define “spherical” modulus of smoothness. So, we prove Stechkin and Jackson-type theorems.

  18. Binding Energy and Compression Modulus of Infinite Nuclear Matter ...

    African Journals Online (AJOL)

    ... MeV at the normal nuclear matter saturation density consistent with the best available density-dependent potentials derived from the G-matrix approach. The results of the incompressibility modulus, k∞ is in excellent agreement with the results of other workers. Journal of the Nigerian Association of Mathematical Physics, ...

  19. On Young's modulus of multi-walled carbon nanotubes

    Indian Academy of Sciences (India)

    WINTEC

    ssion electron microscopy of carbon nanotube/aluminum nanocomposites is given to calculate approximately the. Young's modulus of multi-walled carbon nanotubes. 2. Experimental. Multi-walled carbon nanotubes (MWCNTs) were synthe- sized by arc discharge technique with 20 V d.c. and 100 amps current. The CNT/Al ...

  20. Estimate of K-functionals and modulus of smoothness constructed ...

    Indian Academy of Sciences (India)

    ... and -functionals. The main result of the paper is the proof of the equivalence theorem for a -functional and a modulus of smoothness for the Dunkl transform on R d . Author Affiliations. M El Hamma1 R Daher1. Department of Mathematics, Faculty of Sciences Aïn Chock, University of Hassan II, Casablanca, Morocco ...

  1. In vivo areal modulus of elasticity estimation of the human tympanic membrane system: modelling of middle ear mechanical function in normal young and aged ears

    International Nuclear Information System (INIS)

    Gaihede, Michael; Liao Donghua; Gregersen, Hans

    2007-01-01

    The quasi-static elastic properties of the tympanic membrane system can be described by the areal modulus of elasticity determined by a middle ear model. The response of the tympanic membrane to quasi-static pressure changes is determined by its elastic properties. Several clinical problems are related to these, but studies are few and mostly not comparable. The elastic properties of membranes can be described by the areal modulus, and these may also be susceptible to age-related changes reflected by changes in the areal modulus. The areal modulus is determined by the relationship between membrane tension and change of the surface area relative to the undeformed surface area. A middle ear model determined the tension-strain relationship in vivo based on data from experimental pressure-volume deformations of the human tympanic membrane system. The areal modulus was determined in both a younger (n = 10) and an older (n = 10) group of normal subjects. The areal modulus for lateral and medial displacement of the tympanic membrane system was smaller in the older group (mean = 0.686 and 0.828 kN m -1 , respectively) compared to the younger group (mean = 1.066 and 1.206 kN m -1 , respectively), though not significantly (2p = 0.10 and 0.11, respectively). Based on the model the areal modulus was established describing the summated elastic properties of the tympanic membrane system. Future model improvements include exact determination of the tympanic membrane area accounting for its shape via 3D finite element analyses. In vivo estimates of Young's modulus in this study were a factor 2-3 smaller than previously found in vitro. No significant age-related differences were found in the elastic properties as expressed by the areal modulus

  2. High elastic modulus nanopowder reinforced resin composites for dental applications

    Science.gov (United States)

    Wang, Yijun

    2007-12-01

    Dental restorations account for more than $3 billion dollars a year on the market. Among them, all-ceramic dental crowns draw more and more attention and their popularity has risen because of their superior aesthetics and biocompatibility. However, their relatively high failure rate and labor-intensive fabrication procedure still limit their application. In this thesis, a new family of high elastic modulus nanopowder reinforced resin composites and their mechanical properties are studied. Materials with higher elastic modulus, such as alumina and diamond, are used to replace the routine filler material, silica, in dental resin composites to achieve the desired properties. This class of composites is developed to serve (1) as a high stiffness support to all-ceramic crowns and (2) as a means of joining independently fabricated crown core and veneer layers. Most of the work focuses on nano-sized Al2O3 (average particle size 47 nm) reinforcement in a polymeric matrix with 50:50 Bisphenol A glycidyl methacrylate (Bis-GMA): triethylene glycol dimethacrylate (TEGDMA) monomers. Surfactants, silanizing agents and primers are examined to obtain higher filler levels and enhance the bonding between filler and matrix. Silane agents work best. The elastic modulus of a 57.5 vol% alumina/resin composite is 31.5 GPa compared to current commercial resin composites with elastic modulus alumina, diamond/resin composites are studied. An elastic modulus of about 45 GPa is obtained for a 57 vol% diamond/resin composite. Our results indicate that with a generally monodispersed nano-sized high modulus filler, relatively high elastic modulus resin-based composite cements are possible. Time-dependent behavior of our resin composites is also investigated. This is valuable for understanding the behavior of our material and possible fatigue testing in the future. Our results indicate that with effective coupling agents and higher filler loading, viscous flow can be greatly decreased due to the

  3. Vaginal dilator therapy for women receiving pelvic radiotherapy.

    Science.gov (United States)

    Miles, Tracie; Johnson, Nick

    2010-09-08

    Many vaginal dilator therapy guidelines advocate routine vaginal dilation during and after pelvic radiotherapy to prevent stenosis (abnormal narrowing of the vagina). The UK Gynaecological Oncology Nurse Forum recommend dilation "three times weekly for an indefinite time period". The UK patient charity Cancer Backup advises using vaginal dilators from two to eight weeks after the end of radiotherapy treatment. Australian guidelines recommend dilation after brachytherapy "as soon as is comfortably possible" and "certainly within four weeks and to continue for three years or indefinitely if possible". However, dilation is intrusive, uses health resources and can be psychologically distressing. It has also caused rare but very serious damage to the rectum. To review the benefits and harms of vaginal dilation therapy associated with pelvic radiotherapy for cancer. Searches included the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2008, Issue 4), MEDLINE (1950 to 2008), EMBASE (1980 to 2008) and CINAHL (1982 to 2008). Any comparative randomised controlled trials (RCT) or data of any type which compared dilation or penetration of the vagina after pelvic radiotherapy treatment for cancer. The review authors independently abstracted data and assessed risk of bias. We analysed the mean difference in sexual function scores and the risk ratio for non-compliance at six weeks and three months in single trial analyses. No trials met the inclusion criteria. Dilation during or immediately after radiotherapy can, in rare cases, cause damage and there is no persuasive evidence from any study to demonstrate that it prevents stenosis. Data from one RCT showed no improvement in sexual scores in women who were encouraged to practice dilation. Two case series and one comparative study using historical controls suggest that dilation might be associated with a longer vaginal length but these data cannot reasonably be interpreted to show that dilation

  4. Dilated cardiomyopathy in cats - A case report

    Directory of Open Access Journals (Sweden)

    K. Jeyaraja

    2013-08-01

    Full Text Available Two cats were brought to Madras Veterinary College Teaching Hospital with the history and clinical signs suggestive of congestive heart failure ie, coughing, exercise intolerance, dyspnea, abdominal distension etc. There was history of feeding the cat with home made diet in one case and in other with commercial dog food. Based on electrocardiographic, radiographic and echocardiographic findings, the diagnosis of dilated cardiomyopathy was done in both the cases. The cases were managed with enalapril maleate, furosemide, dietary taurine supplementation and other supportive therapy. Among these two cases, one cat died on 2nd day of treatment and the other showed recovery after 8 days of treatment. [Vet World 2013; 6(4.000: 226-227

  5. A Case Report of Reversible Dilated Cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Abhishek Singhai

    2014-01-01

    Full Text Available Dilated cardiomyopathy (DCM is mostly an idiopathic disease with a progressive and irreversible course. It carries poor prognosis and outcome. Rarely, a reversible metabolic etiology that is amenable to specific therapy is identified. Alteration in thyroid status can lead to changes in systolic and diastolic function of left ventricle. Heart is sensitive to thyroid hormone changes, and cardiac disorders are commonly associated with both hyper and hypothyroidism. Diastolic dysfunction is the most common abnormality reported in hypothyroidism. In systolic function, prolonged systolic time interval or normal cardiac function has been reported by most workers. DCM is a rare presentation of hypothyroidism. Here, we report a case of 40-year-old female diagnosed with DCM due to hypothyroidism

  6. Isolated dilated pupil: Is it adie's pupil?

    Directory of Open Access Journals (Sweden)

    Uma Sinharoy

    2016-01-01

    Full Text Available Adie's tonic pupil, though well known in literature is a rarity in practice. Few case reports have mentioned the occurrence of Adie's pupil during a migraine attack. We report a young female with a history of migraine without aura presenting with asymmetric pupils during migraine attack. Her right pupil was dilated, unresponsive to light with poor response to near reflex. She also had a bilateral loss of ankle jerks. In 0.125% pilocarpine test, the affected pupil responded significantly, and Holmes Adie's syndrome was diagnosed. The patient remained asymptomatic after adjustment of refraction of the right eye for the near vision. It is usually a benign condition. Early clinical detection of such condition is necessary to prevent unnecessary and costly investigations as well to reassure the patient.

  7. Determining the complex modulus of alginate irreversible hydrocolloid dental material.

    Science.gov (United States)

    King, Shalinie; See, Howard; Thomas, Graham; Swain, Michael

    2008-11-01

    The aim of the study is to investigate the visco-elastic response of an alginate irreversible hydrocolloid dental impression material during setting. A novel squeeze film Micro-Fourier Rheometer (MFR, GBC Scientific Equipment, Australia) was used to determine the complex modulus of an alginate irreversible hydrocolloid dental impression material (Algident, ISO 1563 Class A Type 1, Dentalfarm Australia Pty. Ltd.) during setting after mixing. Data was collected every 30s for 10 min in one study and every 10 min for a total of 60 min in another study. A high level of repeatability was observed. The results indicate that the MFR is capable of recording the complex shear modulus of alginate irreversible hydrocolloid for 60 min from the start of mixing and to simultaneously report the changing visco-elastic parameters at all frequencies between 1 Hz and 100 Hz. The storage modulus shows a dramatic increase to 370% of its starting value after 6 min and then reduces to 55% after 60 min. The loss modulus increases to a maximum of 175% of its starting value after 10 min and then reduces to 94% after 60 min. The MFR enables the changes in the complex modulus through the complete setting process to be followed. It is anticipated this approach may provide a better method to compare the visco-elastic properties of impression materials and assist with identification of optimum types for different clinical requirements. The high stiffness of the instrument and the use of band-limited pseudo-random noise as the input signal are the main advantages of this technique over conventional rheometers for determining the changes in alginate visco-elasticity.

  8. Intraventricular vortex properties in nonischemic dilated cardiomyopathy

    Science.gov (United States)

    Benito, Yolanda; Alhama, Marta; Yotti, Raquel; Martínez-Legazpi, Pablo; del Villar, Candelas Pérez; Pérez-David, Esther; González-Mansilla, Ana; Santa-Marta, Cristina; Barrio, Alicia; Fernández-Avilés, Francisco; del Álamo, Juan C.

    2014-01-01

    Vortices may have a role in optimizing the mechanical efficiency and blood mixing of the left ventricle (LV). We aimed to characterize the size, position, circulation, and kinetic energy (KE) of LV main vortex cores in patients with nonischemic dilated cardiomyopathy (NIDCM) and analyze their physiological correlates. We used digital processing of color-Doppler images to study flow evolution in 61 patients with NIDCM and 61 age-matched control subjects. Vortex features showed a characteristic biphasic temporal course during diastole. Because late filling contributed significantly to flow entrainment, vortex KE reached its maximum at the time of the peak A wave, storing 26 ± 20% of total KE delivered by inflow (range: 1–74%). Patients with NIDCM showed larger and stronger vortices than control subjects (circulation: 0.008 ± 0.007 vs. 0.006 ± 0.005 m2/s, respectively, P = 0.02; KE: 7 ± 8 vs. 5 ± 5 mJ/m, P = 0.04), even when corrected for LV size. This helped confining the filling jet in the dilated ventricle. The vortex Reynolds number was also higher in the NIDCM group. By multivariate analysis, vortex KE was related to the KE generated by inflow and to chamber short-axis diameter. In 21 patients studied head to head, Doppler measurements of circulation and KE closely correlated with phase-contract magnetic resonance values (intraclass correlation coefficient = 0.82 and 0.76, respectively). Thus, the biphasic nature of filling determines normal vortex physiology. Vortex formation is exaggerated in patients with NIDCM due to chamber remodeling, and enlarged vortices are helpful for ameliorating convective pressure losses and facilitating transport. These findings can be accurately studied using ultrasound. PMID:24414062

  9. Too Soft to Stick: Influence of Substrate Modulus on Gecko Adhesion

    Science.gov (United States)

    Wilson, Michael; Klittich, Mena; Bernard, Craig; Rodrigo, Rochelle; Keith, Austin; Niewiarowski, Peter; Dhinojwala, Ali

    The gecko adhesion system fascinates biologists and materials scientists alike for its strong, reversible, glue-free, dry adhesion. Geckos encounter a variety of surfaces in their natural habitats; tropical geckos, such as Gekko gecko, encounter hard rough tree trunks as well as soft flexible leaves. Gecko adhesion on a wide variety of hard surfaces has been extensively studied, however there has been no work focused on adhesion to soft surfaces. Here, we investigate for the first time the influence of substrate modulus on gecko adhesion using two different surfaces (cellulose acetate and polydimethylsiloxane). Understanding the limitations of the gecko system is critical for gecko experimental design as well as for the development of synthetic adhesives, particularly in the biomedical field. National Science Foundation.

  10. Thermal Conductivity and Elastic Modulus Evolution of Thermal Barrier Coatings under High Heat Flux Conditions

    Science.gov (United States)

    Zhu, Dongming; Miller, Robert A.

    1999-01-01

    Laser high heat flux test approaches have been established to obtain critical properties of ceramic thermal barrier coatings (TBCs) under near-realistic temperature and thermal gradients that may he encountered in advanced engine systems. Thermal conductivity change kinetics of a thin ceramic coating were continuously monitored in real time at various test temperatures. A significant thermal conductivity increase was observed during the laser simulated engine heat flux tests. For a 0.25 mm thick ZrO2-8%Y2O3 coating system, the overall thermal conductivity increased from the initial value of 1.0 W/m-K to 1. 15 W/m-K, 1. 19 W/m-K and 1.5 W/m-K after 30 hour testing at surface temperatures of 990C, 1100C, and 1320C. respectively. Hardness and modulus gradients across a 1.5 mm thick TBC system were also determined as a function of laser testing time using the laser sintering/creep and micro-indentation techniques. The coating Knoop hardness values increased from the initial hardness value of 4 GPa to 5 GPa near the ceramic/bond coat interface, and to 7.5 GPa at the ceramic coating surface after 120 hour testing. The ceramic surface modulus increased from an initial value of about 70 GPa to a final value of 125 GPa. The increase in thermal conductivity and the evolution of significant hardness and modulus gradients in the TBC systems are attributed to sintering-induced micro-porosity gradients under the laser-imposed high thermal gradient conditions. The test techniques provide a viable means for obtaining coating data for use in design, development, stress modeling, and life prediction for various thermal barrier coating applications.

  11. The Evaluation of Endoscopic Balloon Dilation Treatment for

    Directory of Open Access Journals (Sweden)

    Shokri-Shirvani Javad

    2009-10-01

    Full Text Available Balloon dilatation of stricture is one of the new treatment methods among patients with gastric outlet obstruction (GOO. However, the prevalence and underlying etiologies of GOO in various populations are different. The goal of the present study was to determine the effectiveness of endoscopic balloon dilatation and factors that would affect its success rate patients with benign etiology for GOO. Forty-five patients with the symptoms of benign GOO were randomly selected. Gastric outlet was delineated using double channel videoendoscopy. The information of initial balloon dilation was collected from recorded files. Balloon dilatation was repeated during the mean follow up of 9.9 ± 5.8 months. The severity of gastric pain was measured immediately before balloon dilatation and one month after procedure and was rated on a 10 cm visual analogue scale. The mean age of patients was 43.7 ± 18.1 years and 86.7% of them were men. Furthermore, 71.1% were H pylori positive. Response rate to endoscopic balloon dilatation was 80% and 8 patients underwent surgical resection. Weight loss was more frequent in non-responding group. The pain severity was significantly reduced more in responding subjects. No meaningful relationships were found between the responses to balloon dilatation and positive H pylori and cigarette smoking. Endoscopic balloon dilation is safe and effective for most patients with benign gastric outlet obstruction and has favorable long-term outcome.

  12. 21 CFR 884.4260 - Hygroscopic Laminaria cervical dilator.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hygroscopic Laminaria cervical dilator. 884.4260... Devices § 884.4260 Hygroscopic Laminaria cervical dilator. (a) Identification. A hygroscopic Laminaria... conical and expansible material made from the root of a seaweed (Laminaria digitata or Laminaria japonica...

  13. Micrograft dilators: in pursuit of the undetectable hairline.

    Science.gov (United States)

    Marritt, E

    1988-03-01

    The process of single-hair transplanting, though providing obvious cosmetic advantages in hairline refinement, has long been considered too tedious and time consuming to be incorporated into standard transplant sessions. Micrograft dilators provide dilatation, organization, and hemostasis, while permitting large numbers of micrografts to be placed quickly and effortlessly below the standard transplanted hairline.

  14. Acute gastric dilatation secondary to septicemia in newborn: A rare ...

    African Journals Online (AJOL)

    ... case of acute gastric dilatation that developed in a two-days old child who was born premature and was suffering from septicemia and respiratory distress. The causes and the differential diagnosis of the rare condition are discussed. Keywords: Acute, dilatation, gastric, newborn. African Journal of Paediatric Surgery Vol.

  15. Molecular genetics of dilated cardiomyopathy in the Dobermann dog

    NARCIS (Netherlands)

    Stabej, Polona

    2005-01-01

    Canine dilated cardiomyopathy (DCM) is a disease of the myocardium associated with dilatation and impaired contraction of the ventricles. It primarily affects large and giant breed dogs with Dobermanns being one of the most frequently affected. The high prevalence of DCM in specific breeds suggests

  16. History of urethral catheters and their balloons: drainage, anchorage, dilation, and hemostasis.

    Science.gov (United States)

    Marino, R A; Mooppan, U M; Kim, H

    1993-04-01

    Male urethral catheterization, as practiced in early Greece, was made possible by a sound knowledge of anatomy. It has been preserved by written tradition and advanced by the development of new materials. Balloon dilation, conceived and practiced more than 160 years ago by urologists, has undergone a similar cycle. Some useful ideas, once conceived, have been forgotten and have surfaced again, decades, sometimes centuries, later as new inventions.

  17. Emulsion stability and dilatational viscoelasticity of ovalbumin/chitosan complexes at the oil-in-water interface.

    Science.gov (United States)

    Xiong, Wenfei; Ren, Cong; Tian, Mo; Yang, Xuejun; Li, Jing; Li, Bin

    2018-06-30

    The contribution of the emulsion rheological properties and the viscoelastic of the interface adsorbed layer to the emulsification mechanism of ovalbumin (OVA)-chitosan (CS) mixtures were investigated. In comparison to the treatment with OVA alone and OVA/CS mixtures at pH 4.0, the addition of CS at pH 5.5 increased the size distribution of emulsion droplets with significant flocculation through polyelectrolyte bridging, remarkably enhancing the emulsions stability against gravity creaming after storage at 25 °C for 14 days. The dynamic rheological properties indicated that the formation of the complex at pH 5.5 increased the elastic modulus (G') and apparent viscosity (η ∗ ) of the emulsions, which is useful for inhibiting creaming. Moreover, the complexation of OVA and CS at pH 5.5 increased the dilatational modulus (E), especially the elastic modulus (E d ), of the oil/water interfacial absorbed layer, which could reduce the droplet coalescence and therefore inhibit the growth of emulsion droplets. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. Multigene Genetic Programming for Estimation of Elastic Modulus of Concrete

    Directory of Open Access Journals (Sweden)

    Alireza Mohammadi Bayazidi

    2014-01-01

    Full Text Available This paper presents a new multigene genetic programming (MGGP approach for estimation of elastic modulus of concrete. The MGGP technique models the elastic modulus behavior by integrating the capabilities of standard genetic programming and classical regression. The main aim is to derive precise relationships between the tangent elastic moduli of normal and high strength concrete and the corresponding compressive strength values. Another important contribution of this study is to develop a generalized prediction model for the elastic moduli of both normal and high strength concrete. Numerous concrete compressive strength test results are obtained from the literature to develop the models. A comprehensive comparative study is conducted to verify the performance of the models. The proposed models perform superior to the existing traditional models, as well as those derived using other powerful soft computing tools.

  19. High modulus invert analog glass compositions containing beryllia

    Science.gov (United States)

    Bacon, J. F. (Inventor)

    1974-01-01

    Glass compositions having a Young's modulus of at least 15 million psi and a specific modulus of at least 110 million inches consisting essentially of, in mols, 10-45% SiO2, 2-15% Li2O, 3-34% BeO, 12-36% of at least one bivalent oxide selected from the group consisting of CaO, ZnO, MgO and CuO, 10-39% of at least one trivalent oxide selected from the group consisting of Al2O3, B2O3, La2O3, Y2O3 and the mixed rare earth oxides, the total number of said bivalent and trivalent oxides being at least three, and up to 10% of a tetravalent oxide selected from the group consisting of ZrO2, TiO2 and CeO2.

  20. Simplified equation for Young's modulus of CNT reinforced concrete

    Science.gov (United States)

    Chandran, RameshBabu; Gifty Honeyta A, Maria

    2017-12-01

    This research investigation focuses on finite element modeling of carbon nanotube (CNT) reinforced concrete matrix for three grades of concrete namely M40, M60 and M120. Representative volume element (RVE) was adopted and one-eighth model depicting the CNT reinforced concrete matrix was simulated using FEA software ANSYS17.2. Adopting random orientation of CNTs, with nine fibre volume fractions from 0.1% to 0.9%, finite element modeling simulations replicated exactly the CNT reinforced concrete matrix. Upon evaluations of the model, the longitudinal and transverse Young's modulus of elasticity of the CNT reinforced concrete was arrived. The graphical plots between various fibre volume fractions and the concrete grade revealed simplified equation for estimating the young's modulus. It also exploited the fact that the concrete grade does not have significant impact in CNT reinforced concrete matrix.

  1. Connecting Jacobi elliptic functions with different modulus parameters

    Indian Academy of Sciences (India)

    Most properties of Jacobi elliptic functions found in the literature do not involve any change in the modulus parameter m. For example, the quadratic relations cn2(x, m)=1 − sn2(x, m), dn2(x, m)=1 − msn2(x, m),. (2) and the addition formulas for sn(x + y, m), cn(x + y, m), dn(x + y, m) just involve. Jacobi elliptic functions with the ...

  2. Resin composites: Modulus of elasticity and marginal quality.

    Science.gov (United States)

    Benetti, Ana R; Peutzfeldt, Anne; Lussi, Adrian; Flury, Simon

    2014-09-01

    To investigate how the modulus of elasticity of resin composites influences marginal quality in restorations submitted to thermocyclic and mechanical loading. Charisma, Filtek Supreme XTE and Grandio were selected as they were found to possess different moduli of elasticity but quite similar polymerization contraction. MOD cavities (n=30) were prepared in extracted premolars, restored and then subjected to thermocyclic and mechanical loading. Marginal quality of the restorations before and after loading was analyzed on epoxy replicas under a scanning electron microscope. The percentage of gap-free margins and occurrence of paramarginal fractures were registered. Modulus of elasticity and polymerization contraction were analyzed with parametric and margins with nonparametric ANOVA and post hoc Tukey HSD or Wilcoxon rank-sum tests, respectively. The number of paramarginal fractures was analyzed with exact Fisher tests (α=0.05). Grandio demonstrated significantly more gap-free enamel margins than Charisma and Filtek Supreme XTE, before and after loading (p0.05). No significant effect of resin composite (p=0.81) on the quality of dentine margins was observed, before or after loading. Deterioration of all margins was evident after loading (pGrandio when compared to Charisma (p=0.008). The resin composite with the highest modulus of elasticity resulted in the highest number of gap-free enamel margins but with an increased incidence of paramarginal enamel fractures. The results from this study suggest that the marginal quality of restorations can be improved by the selection of a resin composite with modulus of elasticity close to that of dentine, although an increase in paramarginal enamel fractures can result as a consequence. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Using data logging to measure Young’s modulus

    Science.gov (United States)

    Richardson, David

    2018-03-01

    Historically the Young’s modulus of a material is measured by increasing the applied force to a wire and measuring the extension. The cross sectional area and original length allow this to be plotted as a graph of stress versus strain. This article describes how data logging sensors can be used to measure how the force changes with extension, allowing a strain versus stress graph to be plotted into the region of plastic deformation.

  4. A maximum modulus theorem for the Oseen problem

    Czech Academy of Sciences Publication Activity Database

    Kračmar, S.; Medková, Dagmar; Nečasová, Šárka; Varnhorn, W.

    2013-01-01

    Roč. 192, č. 6 (2013), s. 1059-1076 ISSN 0373-3114 R&D Projects: GA ČR(CZ) GAP201/11/1304; GA MŠk LC06052 Institutional research plan: CEZ:AV0Z10190503 Keywords : Oseen problem * maximum modulus theorem * Oseen potentials Subject RIV: BA - General Mathematics Impact factor: 0.909, year: 2013 http://link.springer.com/article/10.1007%2Fs10231-012-0258-x

  5. Charged string solutions with dilaton and modulus fields

    CERN Document Server

    Cvetic, M

    1994-01-01

    We find charged, abelian, spherically symmetric solutions (in flat space-time) corresponding to the effective action of $D=4$ heterotic string theory with scale-dependent dilaton $\\p$ and modulus $\\vp$ fields. We take into account perturbative (genus-one), moduli-dependent `threshold' corrections to the coupling function $f(\\p,\\vp)$ in the gauge field kinetic term $f(\\p,\\vp) F^2_{\\m\

  6. Determination of dynamic Young’s modulus of vulnerable speleothems

    Czech Academy of Sciences Publication Activity Database

    Konečný, Pavel; Lednická, Markéta; Souček, Kamil; Staš, Lubomír; Kubina, Lukáš; Gribovszki, K.

    2015-01-01

    Roč. 20, č. 2 (2015), s. 156-163 ISSN 1335-1788 R&D Projects: GA MŠk ED2.1.00/03.0082; GA MŠk(CZ) LO1406 Institutional support: RVO:68145535 Keywords : dynamic Young´s modulus * speleothem * bulk density * X-Ray Computed Tomography Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.390, year: 2015 http://actamont.tuke.sk/pdf/2015/n2/10Konecny.pdf

  7. Quantification of left ventricular dilatation in myocardial perfusion scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Mauren B. Azambuja, E-mail: medicinanuclear@hsvp.com.b, E-mail: mauren.gonzalez@gmail.co [Pontificia Universidade Catolica do Rio Grande do Sul (PUC-RS), Porto Alegre, RS (Brazil). Clinica Medica. Programa de Pos-Graduacao em Medicina e Ciencias da Saude; Azambuja, Roberto Alves [Hospital Sao Vicente de Paulo, Passo Fundo, RS (Brazil); Bodanese, Luiz Carlos [Pontificia Universidade Catolica do Rio Grande do Sul (PUC-RS), Porto Alegre, RS (Brazil). Hospital Sao Lucas. Serv. de Cardiologia

    2011-05-15

    Background: the rate of transient dilatation can be determined by exercise testing or pharmacological stress test. It is unknown whether the type of stress has an impact on average transient dilatation index values. Objective: to compare average transient dilation index values in 99mTc-sestamibi scintigraphy in patients undergoing treadmill stress test, versus dipyridamole stress test. The secondary purpose was to evaluate the impact on the average index value by demographic characteristics, risk factors for coronary artery disease and severity of ischemia. Methods: the cross-sectional study included 200 patients between 40 and 70 years old, with or without risk factors for ischemic heart disease, with or without a previous diagnosis of ischemic heart disease. The separation between groups was sequential. The software 4D-MSPECT calculated the transient dilatation index and provided a scoring system for perfusion analysis. Results: the average transient dilation index value of the group undergoing exercise stress test was 1.06 ({+-}0.23). For the group undergoing the dipyridamole stress test, it was 1.10 ({+-}0.22); (p = 0.200). There was no association between the type of stress and the average transient dilatation index values. An association was found between the average index values and age only for those patients from the exercise test group (p = 0.009). Conclusion: the results of our study demonstrate that the transient dilation index does not differ when patients undergo exercise stress test on a treadmill or pharmacological stress by dipyridamole. (author)

  8. 3D mapping of elastic modulus using shear wave optical micro-elastography

    Science.gov (United States)

    Zhu, Jiang; Qi, Li; Miao, Yusi; Ma, Teng; Dai, Cuixia; Qu, Yueqiao; He, Youmin; Gao, Yiwei; Zhou, Qifa; Chen, Zhongping

    2016-01-01

    Elastography provides a powerful tool for histopathological identification and clinical diagnosis based on information from tissue stiffness. Benefiting from high resolution, three-dimensional (3D), and noninvasive optical coherence tomography (OCT), optical micro-elastography has the ability to determine elastic properties with a resolution of ~10 μm in a 3D specimen. The shear wave velocity measurement can be used to quantify the elastic modulus. However, in current methods, shear waves are measured near the surface with an interference of surface waves. In this study, we developed acoustic radiation force (ARF) orthogonal excitation optical coherence elastography (ARFOE-OCE) to visualize shear waves in 3D. This method uses acoustic force perpendicular to the OCT beam to excite shear waves in internal specimens and uses Doppler variance method to visualize shear wave propagation in 3D. The measured propagation of shear waves agrees well with the simulation results obtained from finite element analysis (FEA). Orthogonal acoustic excitation allows this method to measure the shear modulus in a deeper specimen which extends the elasticity measurement range beyond the OCT imaging depth. The results show that the ARFOE-OCE system has the ability to noninvasively determine the 3D elastic map. PMID:27762276

  9. Quadricuspid Aortic Valve Combined with Moderate Ascending Aortic Dilatation

    Science.gov (United States)

    Uspenskiy, Vladimir E.; Osadchii, Alexei M.; Gordeev, Mikhail L.

    2015-01-01

    The quadricuspid aortic valve is a very uncommon malformation associated with aortic insufficiency, aortic stenosis, endocarditis, and ascending aortic dilatation. We report four cases of this aortic valve malformation. One patient with severe aortic regurgitation and moderate aortic dilatation required aortic valve replacement. Three patients had mild or moderate aortic insufficiency combined with moderate ascending aortic dilatation. These patients were referred to follow-up. The presented cases demonstrate that this aortic valve malformation may not be as rare as it appears and that attention must be paid to any quadricuspid findings during computed tomographic angiography and echocardiography. PMID:27390747

  10. Spatial Markov Semigroups Admit Hudson-Parthasarathy Dilations

    OpenAIRE

    Skeide, Michael

    2008-01-01

    For many Markov semigroups dilations in the sense of Hudson and Parthasarathy, that is a dilation which is a cocycle perturbation of a noise, have been constructed with the help of quantum stochastic calculi. In these notes we show that every Markov semigroup on the algebra of all bounded operators on a separable Hilbert space that is spatial in the sense of Arveson, admits a Hudson-Parthasarathy dilation. In a sense, the opposite is also true. The proof is based on general results on the the...

  11. Characterization and Long-Term Prognosis of Postmyocarditic Dilated Cardiomyopathy Compared With Idiopathic Dilated Cardiomyopathy.

    Science.gov (United States)

    Merlo, Marco; Anzini, Marco; Bussani, Rossana; Artico, Jessica; Barbati, Giulia; Stolfo, Davide; Gigli, Marta; Muça, Matilda; Naso, Paola; Ramani, Federica; Di Lenarda, Andrea; Pinamonti, Bruno; Sinagra, Gianfranco

    2016-09-15

    Dilated cardiomyopathy (DC) is the final common pathway of different pathogenetic processes and presents a significant prognostic heterogeneity, possibly related to its etiologic variety. The characterization and long-term prognosis of postmyocarditic dilated cardiomyopathy (PM-DC) remain unknown. This study assesses the clinical-instrumental evolution and long-term prognosis of a large cohort of patients with PM-DC. We analyzed 175 patients affected with DC consecutively enrolled from 1993 to 2008 with endomyocardial biopsy (EMB) data available. PM-DC was defined in the presence of borderline myocarditis at EMB or persistent left ventricular dysfunction 1 year after diagnosis of active myocarditis at EMB. Other patients were defined as affected by idiopathic dilated cardiomyopathy (IDC). Analysis of follow-up evaluations was performed at 24, 60, and 120 months. We found 72 PM-DC of 175 enrolled patients (41%). Compared with IDC, patients with PM-DC were more frequently females and less frequently presented a familial history of DC. No other baseline significant differences were found. During the long-term follow-up (median 154, first to third interquartile range 78 to 220 months), patients with PM-DC showed a trend toward slower disease progression. Globally, 18 patients with PM-DC (25%) versus 49 with IDC (48%) experienced death/heart transplantation (p = 0.045). The prognostic advantage for patients with PM-DC became significant beyond 40 months of follow-up. At multivariable time-dependent Cox analysis, PM-DC was confirmed to have a global independent protective role (hazard ratio 0.53, 95% confidence interval 0.28 to 0.97, p = 0.04). In conclusion, PM-DC is characterized by better long-term prognosis compared with IDC. An exhaustive etiologic characterization appears relevant in the prognostic assessment of DC. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Changes in overall ventricular myocardial architecture in the setting of a porcine animal model of right ventricular dilation

    DEFF Research Database (Denmark)

    Agger, Peter; Ilkjær, Christine; Laustsen, Christoffer

    2017-01-01

    BACKGROUND: Chronic pulmonary regurgitation often leads to myocardial dysfunction and heart failure. It is not fully known why secondary hypertrophy cannot fully protect against the increase in wall stress brought about by the increased end-diastolic volume in ventricular dilation. It has been...... of their hearts permitted measurement of the orientation of the cardiomyocytes. RESULTS: The helical angles in the right ventricle approached a more circumferential orientation in the setting of right ventricular RV dilation (p = 0.007), with an increased proportion of surface-parallel cardiomyocytes. In contrast...... the achievement of normalisation of cardiomyocytic strain, affecting overall contractility. We suggest that the aetiology of the cardiac failure induced by right vetricular dilation may be partly explained by morphological changes in the myocardium itself....

  13. Evaluation of Variability in Resilient Modulus Test Results (ASTM D4123)

    Science.gov (United States)

    1989-10-01

    Samples of asphalt mixture were evaluated in the laboratory under various conditions to evaluate the repeatability of the resilient modulus test and to evaluate the effect of stress on the measured resilient modulus. Some of the samples were prepared...

  14. Standardizing lightweight deflectometer modulus measurements for compaction quality assurance : research summary.

    Science.gov (United States)

    2017-09-01

    The mechanistic-empirical pavement design method requires the elastic resilient modulus as the key input for characterization of geomaterials. Current density-based QA procedures do not measure resilient modulus. Additionally, the density-based metho...

  15. Developing an economical and reliable test for measuring the resilient modulus and Poisson's ratio of subgrade.

    Science.gov (United States)

    2010-11-01

    The resilient modulus and Poissons ratio of base and sublayers in highway use are : important parameters in design and quality control process. The currently used techniques : include CBR (California Bearing Ratio) test, resilient modulus test,...

  16. Determination of resilient modulus values for typical plastic soils in Wisconsin.

    Science.gov (United States)

    2011-09-01

    "The objectives of this research are to establish a resilient modulus test results database and to develop : correlations for estimating the resilient modulus of Wisconsin fine-grained soils from basic soil properties. A : laboratory testing program ...

  17. Inactivation of Lrp5 in osteocytes reduces young's modulus and responsiveness to the mechanical loading.

    Science.gov (United States)

    Zhao, Liming; Shim, Joon W; Dodge, Todd R; Robling, Alexander G; Yokota, Hiroki

    2013-05-01

    Low-density-lipoprotein receptor-related protein 5 (Lrp5) is a co-receptor in Wnt signaling, which plays a critical role in development and maintenance of bone. Osteoporosis-pseudoglioma syndrome, for instance, arises from loss-of-function mutations in Lrp5, and global deletion of Lrp5 in mice results in significantly lower bone mineral density. Since osteocytes are proposed to act as a mechanosensor in the bone, we addressed a question whether a conditional loss-of-function mutation of Lrp5 selective to osteocytes (Dmp1-Cre;Lrp5(f/f)) would alter responses to ulna loading. Loading was applied to the right ulna for 3 min (360 cycles at 2Hz) at a peak force of 2.65 N for 3 consecutive days, and the contralateral ulna was used as a non-loaded control. Young's modulus was determined using a midshaft section of the femur. The results showed that compared to age-matched littermate controls, mice lacking Lrp5 in osteocytes exhibited smaller skeletal size with reduced bone mineral density and content. Compared to controls, Lrp5 deletion in osteocytes also led to a 4.6-fold reduction in Young's modulus. In response to ulna loading, mineralizing surface, mineral apposition rate, and bone formation rate were diminished in mice lacking Lrp5 in osteocytes by 52%, 85%, and 69%, respectively. Collectively, the results support the notion that the loss-of-function mutation of Lrp5 in osteocytes causes suppression of mechanoresponsiveness and reduces bone mass and Young's modulus. In summary, Lrp5-mediated Wnt signaling significantly contributes to maintenance of mechanical properties and bone mass. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Dilation-and-modulation systems on the half real line

    Directory of Open Access Journals (Sweden)

    Yun-Zhang Li

    2016-07-01

    Full Text Available Abstract Translation, dilation, and modulation are fundamental operations in wavelet analysis. Affine frames based on translation-and-dilation operation and Gabor frames based on translation-and-modulation operation have been extensively studied and seen great achievements. But dilation-and-modulation frames have not. This paper addresses a class of dilation-and-modulation systems in L 2 ( R + $L^{2}(\\mathbb {R}_{+}$ . We characterize frames, dual frames, and Parseval frames in L 2 ( R + $L^{2}(\\mathbb {R}_{+}$ generated by such systems. Interestingly, it turns out that, for such systems, Parseval frames, orthonormal bases, and orthonormal systems are mutually equivalent to each other, while this is not the case for affine systems and Gabor systems.

  19. Autologous bone marrow mononuclear cell delivery to dilated ...

    African Journals Online (AJOL)

    Autologous bone marrow mononuclear cell delivery to dilated cardiomyopathy patients: A clinical trial. PLN Kaparthi, G Namita, LK Chelluri, VSP Rao, PK Shah, A Vasantha, SK Ratnakar, K Ravindhranath ...

  20. Apparatus for in-situ nondestructive measurement of Young's modulus of plate structures

    Science.gov (United States)

    Huang, Jerry Qixin (Inventor); Perez, Robert J. (Inventor); DeLangis, Leo M. (Inventor)

    2005-01-01

    A method and apparatus for determining stiffness of a plate-like structure including a monolithic or composite laminate plate entails disposing a device for generating an acoustical pulse against a surface of the plate and disposing a detecting device against the same surface spaced a known distance from the pulse-generating device, and using the pulse-generating device to emit a pulse so as to create an extensional wave in the plate. The detecting device is used to determine a time of flight of the wave over the known distance, and the wave velocity is calculated. A Young's modulus of the plate is determined by a processor based on the wave velocity. Methods and apparatus for evaluating both isotropic plates and anisotropic laminates are disclosed.

  1. Low modulus Ti–Nb–Hf alloy for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    González, M., E-mail: Marta.Gonzalez.Colominas@upc.edu [Department of Materials Science and Metallurgy, Universitat Politècnica de Catalunya (UPC), Avda. Diagonal 647, 08028 Barcelona (Spain); Materials Science, Elisava Escola Superior de Disseny i Enginyeria de Barcelona, La Rambla 30-32, 08002 Barcelona (Spain); Peña, J. [Department of Materials Science and Metallurgy, Universitat Politècnica de Catalunya (UPC), Avda. Diagonal 647, 08028 Barcelona (Spain); Materials Science, Elisava Escola Superior de Disseny i Enginyeria de Barcelona, La Rambla 30-32, 08002 Barcelona (Spain); Gil, F.J.; Manero, J.M. [Department of Materials Science and Metallurgy, Universitat Politècnica de Catalunya (UPC), Avda. Diagonal 647, 08028 Barcelona (Spain); Ciber-BBN (Spain)

    2014-09-01

    β-Type titanium alloys with a low elastic modulus are a potential strategy to reduce stress shielding effect and to enhance bone remodeling in implants used to substitute failed hard tissue. For biomaterial application, investigation on the mechanical behavior, the corrosion resistance and the cell response is required. The new Ti25Nb16Hf alloy was studied before and after 95% cold rolling (95% C.R.). The mechanical properties were determined by tensile testing and its corrosion behavior was analyzed by potentiostatic equipment in Hank's solution at 37 °C. The cell response was studied by means of cytotoxicity evaluation, cell adhesion and proliferation measurements. The stress–strain curves showed the lowest elastic modulus (42 GPa) in the cold worked alloy and high tensile strength, similar to that of Ti6Al4V. The new alloy exhibited better corrosion resistance in terms of open circuit potential (E{sub OCP}), but was similar in terms of corrosion current density (i{sub CORR}) compared to Ti grade II. Cytotoxicity studies revealed that the chemical composition of the alloy does not induce cytotoxic activity. Cell studies in the new alloy showed a lower adhesion and a higher proliferation compared to Ti grade II presenting, therefore, mechanical features similar to those of human cortical bone and, simultaneously, a good cell response. - Highlights: • Presents low elastic modulus and high strength and elastic deformability. • Exhibits good biocompatibility in terms of cytotoxicity and cell response. • Corrosion resistance of this alloy is good, similar to that of Ti grade II. • Potential candidate for implants used to substitute failed hard tissue.

  2. The Evaluation of Endoscopic Balloon Dilation Treatment for Benign

    Directory of Open Access Journals (Sweden)

    H. Ghofrani

    2008-04-01

    Full Text Available Background and ObjectiveBalloon dilatation of stricture is one of the new treatment methods for patients with Gastric Outlet Obstruction (GOO. Prevalence and underlying etiologies of GOO in various populations are different. The goal of the present study was to determine the effectiveness of endoscopic balloon dilatation and factors that could affect method advantage among patients with benign etiology for GOO. Methods Forty-five patients with symptoms of benign GOO were randomly selected. The mean age of patients was 43.7±18.1 years and 86.7% of them were men. Gastric outlet was delineated using double channel videoendoscopy. The severity of gastric pain was measured by VAS test immediately before and one month after balloon dilatation. Patients were followed after procedure weekly (for the first month and then monthly. Balloon dilatation was repeated for 27% patients during the follow up period.ResultsPatients were followed for 9.9±5.8 months. Furthermore, 71.1% were H. pylori positive. Positive response percent to endoscopic balloon dilatation was 80% and eight patients were took under surgical resection. Weight loss was seen frequently in the non-respondent group. The pain severity was significantly reduced in respondent subjects. No meaningful correlations were found between the response to balloon dilatation and positive H. pylori and cigarette smoking.ConclusionEndoscopic balloon dilatation is a safe and effective method for treating most of patients with benign gastric outlet obstruction and has favorable long-term outcome. Keywords: Endoscopy, Gastric Outlet Obstruction (GOO, Balloon Dilatation

  3. Minimal Cuntz–Krieger dilations and representations of Cuntz ...

    Indian Academy of Sciences (India)

    A-relations we show that there exists a unique minimal dilation to generators of Cuntz–. Krieger algebras or its ... properties of the minimal Cuntz–Krieger dilation and the WOT-closed algebra generated by it is studied in terms ... is equivalent to saying that the operator (T1,...,Tn) from H ⊕···⊕ H (n-times) to H is a contraction.

  4. Non-obstructive cecal dilatation and perforation after cesarean section

    DEFF Research Database (Denmark)

    Sperling, Lene; Schantz, A L; Toftager-Larsen, K

    1990-01-01

    A case of non-obstructive cecal dilatation and perforation after cesarean section is reported, with a review of the literature on the diagnosis and management of this entity. Fifteen cases have been described. Attention is called to this rare complication and to the accompanying pseudo......-obstructive syndrome, the diagnosis of which is important in order to avoid cecal perforation. Non-obstructive cecal dilatation is a life threatening complication to cesarean section, and immediate surgical intervention is important....

  5. An unusual triad: Bilateral dilated odontoma, hypodontia and peg laterals

    Directory of Open Access Journals (Sweden)

    Alphy Alphonsa Sebastian

    2013-01-01

    The aim of this case report is to present a rare case of bilateral dilated odontoma affecting a microdontic permanent lateral incisor in a 30 year old female patient with hypodontia and peglateral teeth with its clinical, radiological and histological features, which has yet been not reported. Bilateral presence of dilated odontoma is not a common occurrence, although a single tooth involvement in each case has been reported in the literature.

  6. Sciatica caused by a dilated epidural vein: MR findings

    Energy Technology Data Exchange (ETDEWEB)

    Demaerel, P.; Petre, C.; Wilms, G. [Dept. of Radiology, Catholic University of Leuven (Belgium); Plets, C. [Dept. of Neurosurgery, Catholic University of Leuven (Belgium)

    1999-02-01

    We report the MR imaging findings in a 41-year-old woman presenting with sudden low back pain and sciatica. At surgery a dilated epidural vein was found compressing the nerve root. The MR findings may suggest the diagnosis. Magnetic resonance imaging of a dilated epidural vein or varix causing sciatica has not been reported until now. (orig.) (orig.) With 1 fig., 4 refs.

  7. Mechanical Components from Highly Recoverable, Low Apparent Modulus Materials

    Science.gov (United States)

    Padula, Santo, II (Inventor); Noebe, Ronald D. (Inventor); Stanford, Malcolm K. (Inventor); DellaCorte, Christopher (Inventor)

    2015-01-01

    A material for use as a mechanical component is formed of a superelastic intermetallic material having a low apparent modulus and a high hardness. The superelastic intermetallic material is conditioned to be dimensionally stable, devoid of any shape memory effect and have a stable superelastic response without irrecoverable deformation while exhibiting strains of at least 3%. The method of conditioning the superelastic intermetallic material is described. Another embodiment relates to lightweight materials known as ordered intermetallics that perform well in sliding wear applications using conventional liquid lubricants and are therefore suitable for resilient, high performance mechanical components such as gears and bearings.

  8. Connection between ''exchange'' contribution to elastic modulus and spontaneous magnetostriction

    International Nuclear Information System (INIS)

    Deryabin, A.V.; Kazantsev, V.K.; Shevtsov, B.N.

    1985-01-01

    Transformation of temperature dependences of thermal expansion coefficient, elastic modulus, magnetic and magnetostriction susceptibility is studied at concentration magnetic transitions in quasi-bi nary sections of Fesub(65)Nisub(35-x)Crsub(x), Fesub(50)Nisub(50-x)Mnsub(x), Crsub(10)Fesub(x)Nisub(90-x). It is shown that the ratio between exchange contribution to the elastic modules ΔEsub(A) and a value of spontaneous magnetostriction w sub(m) is not practicall dependent on temperature and composition. Unambiguous relation between ΔEsub(A) and w sub(m) testifies on the unique nature of invar anomaly of thermal expansion and elasticity

  9. Treatment of urethral strictures with balloon dilation: A forgotten tale

    Directory of Open Access Journals (Sweden)

    Konstantinos Stamatiou

    2015-09-01

    Full Text Available Urethral stricture is a common condition that can lead to serious complications such as urinary infections and renal insufficiency secondary to urinary retention. Treatment options include catheterization and dilation, urethroplasty and endoscopic internal urethrotomy as well. Although treatment option depends on the type, length and aetiology of stricture, the choice can be influenced to varying degrees by the simplicity of the method, the preferences of the patient the available accoutrements and the patient health condition. Both urethroplasty and endoscopic internal urethrotomy require anaesthesia and thus are not suitable for many elder and unfit for surgical treatment patients. On the other hand, dilations are easy to perform in every day clinical practice however they have been associated with iatrogenic urethral trauma. In contrast, balloon dilation under vision dilates by radial application of forces against the stricture, avoiding the potentially shearing forces associated with sequential rigid dilation. Since it reduces the possibility of an iatrogenic urethral trauma and the subsequent spongiofibrosis may lead into improved therapeutic outcomes. In this report we describe a technique for the treatment of urethral strictures with balloon dilation in elder and unfit for surgical treatment patients.

  10. Spectral dilation of L(B,H)-valued measures and its application to stationary dilation for Banach space valued processes

    Science.gov (United States)

    Miamee, A. G.

    1989-01-01

    Let B be a Banach space and H and K to Hilbert spaces. The spectral dilation of L(B,H)-valued measures is studied and it is shown that the recent results of Makagon and Salehi (1986) and Rosenberg (1982) on the dilation of L(K,H)-valued measures can be extended to hold for the general Banach space setting of L(B,H)-valued measures. These L(B,H)-valued measures are closely connected to the Banach space valued processes. This connection is recalled and as application of spectral dilation of L(B,H)-valued measures the well known stationary dilation results for scalar valued processes is extended to the case of Banach space valued processes.

  11. Temperature Effects on Adhesive Bond Strengths and Modulus for Commonly Used Spacecraft Structural Adhesives

    Science.gov (United States)

    Ojeda, Cassandra E.; Oakes, Eric J.; Hill, Jennifer R.; Aldi, Dominic; Forsberg, Gustaf A.

    2011-01-01

    A study was performed to observe how changes in temperature and substrate material affected the strength and modulus of an adhesive bondline. Seven different adhesives commonly used in aerospace bonded structures were tested. Aluminum, titanium and Invar adherends were cleaned and primed, then bonded using the manufacturer's recommendations. Following surface preparation, the coupons were bonded with the adhesives. The single lap shear coupons were then pull tested per ASTM D 1002 Standard Test Method for Apparent Shear Strength of Single- Lap-Joint over a temperature range from -150 deg C up to +150 deg C. The ultimate strength was calculated and the resulting data were converted into B-basis design allowables. Average and Bbasis results were compared. Results obtained using aluminum adherends are reported. The effects of using different adherend materials and temperature were also studied and will be reported in a subsequent paper. Dynamic Mechanical Analysis (DMA) was used to study variations in adhesive modulus with temperature. This work resulted in a highly useful database for comparing adhesive performance over a wide range of temperatures, and has facilitated selection of the appropriate adhesive for spacecraft structure applications.

  12. Low-modulus PMMA bone cement modified with castor oil.

    Science.gov (United States)

    López, Alejandro; Hoess, Andreas; Thersleff, Thomas; Ott, Marjam; Engqvist, Håkan; Persson, Cecilia

    2011-01-01

    Some of the current clinical and biomechanical data suggest that vertebroplasty causes the development of adjacent vertebral fractures shortly after augmentation. These findings have been attributed to high injection volumes as well as high Young's moduli of PMMA bone cements compared to that of the osteoporotic cancellous bone. The aim of this study was to evaluate the use of castor oil as a plasticizer for PMMA bone cements. The Young's modulus, yield strength, maximum polymerization temperature, doughing time, setting time and the complex viscosity curves during curing, were determined. The cytotoxicity of the materials extracts was assessed on cells of an osteoblast-like cell line. The addition of up to 12 wt% castor oil decreased yield strength from 88 to 15 MPa, Young's modulus from 1500 to 446 MPa and maximum polymerization temperature from 41.3 to 25.6°C, without affecting the setting time. However, castor oil seemed to interfere with the polymerization reaction, giving a negative effect on cell viability in a worst-case scenario.

  13. Treatment of Ureterointestinal Anastomotic Strictures by Diathermal or Cryoplastic Dilatation

    International Nuclear Information System (INIS)

    Orsi, Franco; Penco, Silvia; Matei, Victor; Bonomo, Guido; Vigna, Paolo Della; Monfardini, Lorenzo; Cobelli, Ottavio De

    2007-01-01

    Background. Ureterointestinal anastomotic strictures (UAS) complicate 10-15% of surgeries for urinary diversion and are the main cause of deterioration in renal function. Treatments are surgical revision, management with autostatic stent, balloon dilatation, endoscopic incision, and percutaneous transrenal diathermy (Acucise). A new option is cryoplastic dilatation (Polar-Cath). Purpose. To assess the feasibility, complications, and preliminary results of UAS treatment using the Acucise and Polar-Cath systems. Methods. Nineteen UAS, diagnosed by ultrasonography or computed tomography and sequential renal scintigraphy, occurred in 15 cancer patients after radical cystectomy and urinary diversion. Fifteen were managed with balloon diathermy and 4 by balloon cryoplasty in a three-stage procedure-percutaneous nephrostomy, diathermal or cryoplastic dilatation, and transnephrostomic control with nephrostomy removal-each separated by 15 days. All patients gave written informed consent. Results. Dilatations were successful in all cases. The procedure is simple and rapid (about 45 min) under fluoroscopic control and sedation. Procedural complications occurred in 1 (5%) patient with UAS after Wallace II uretero-ileocutaneostomy: a common iliac artery lesion was induced by diathermal dilatation, evident subsequently, and required surgical repair. Patency with balloon diathermy was good, with two restenoses developing over 12 months (range 1-22) of follow-up. With balloon cryoplastic dilatation, one restenosis developed in the short term; follow-up is too brief to assess the long-term efficacy. Conclusion. Our short-term results with diathermal and cryoplastic dilatation to resolve UAS are good. If supported by longer follow-up, the techniques may be considered as first-choice approaches to UAS. Surgery should be reserved for cases in which this minimally invasive technique fails

  14. Effect of time of sintering of a castable with andalusite aggregates in the rupture modulus and elastic modulus

    International Nuclear Information System (INIS)

    Oliveira, M.R.; Garcia, G.C.R.; Claudinei, S.; Ribeiro, S.

    2011-01-01

    The studied castable contain andalusite aggregates, and when sintered in temperatures above 1280 deg C, transformed into mullite improving the properties of concrete due to its low expansion and thermal conductivity, creep resistance and thermal shock. The refractory was homogenized in a mixer with 5.5% m/m of water and poured into a metal mold resulting in prismatic bars. After curing for 48 hours, were sintered at 1450 ° C for 0 h, 1 h, 2.5 h and 10 h with heating and cooling rates of 2 ° C / min. The results of elastic modules were, respectively, in GPa: 25.75±1.75, 37.79±0.36, 39.03±1.97 and 54.47±4.01, and rupture, MPa: 8.40±0.78, 11.94±0.68, 10.91±0.91 and 11,34±1.16, showing the increase in elastic modulus for longer times and for times exceeding one hour, no significant changes in results of the modulus of rupture , stabilizing the change of this refractory's properties after the first hour of sintering. (author)

  15. Characterizing the elastic shear modulus of a soft medium via a thermally induced elastic shear wave in thermodynamic equilibrium

    Science.gov (United States)

    Chang, Sheng-Yi; Lee, Sanboh; Chen, Wei-Ru; Lee, Ming-Yih; Chou, Chien

    2018-03-01

    A novel method to characterize the elastic shear modulus of an isotropic, homogeneous and extremely soft material based on a thermally induced elastic shear wave (TIESW) under thermodynamic equilibrium at room temperature is proposed. The temporal evolution of the TIESW on the surface of a squared polyvinyl acetate (PVA) specimen is observed, while the oscillation frequency of the TIESW is measured by using a two-frequency polarized heterodyne interferometer. In experiments, the oscillation frequency of the TIESW in PVA specimens is in the range of 10‑3 Hz, which is equivalent to µPa on the elastic shear modulus. The features and advantages of the TIESW-based method in comparison to conventional methods are discussed.

  16. Change in dynamic visual acuity (DVA) by pupil dilation.

    Science.gov (United States)

    Ueda, Tetsuo; Nawa, Yoshiaki; Yukawa, Eiichi; Taketani, Futoshi; Hara, Yoshiaki

    2006-01-01

    This study was conducted to assess dynamic visual acuity (DVA) under pupil dilation. Pupil dilation may negatively affect driving performance. Thirty healthy young adults (mean age 29.4 years) with pupil dilation participated in this study as the Mydrin P group. In addition to them, 15 healthy young adults (mean age 28.5 years) without pupil dilation were enrolled as the control group. DVA was measured binocularly with free-head viewing at 0, 30, 60, 120, and 360 min after mydriatic drop instillation in both eyes. Pupil size was measured at each time. In the Mydrin P group, DVA significantly improved at 30, 60, and 120 min (ANOVA; p DVA did not significantly change at all measured times (ANOVA; p > .9). DVA was significantly (p DVA was related to the enlargement of the pupil. This study suggests that the pupil size is one factor that may affect DVA. Potential applications of this study include useful information to assess the effect of pupil dilation on driving performance.

  17. Exploring Biological Motion Processing in Parkinson's Disease Using Temporal Dilation.

    Directory of Open Access Journals (Sweden)

    Ruihua Cao

    Full Text Available Biological motion (BM perception is the compelling ability of the visual system to perceive complex animated movements effortlessly and promptly. A recent study has shown that BM can automatically lengthen perceived temporal duration independent of global configuration. The present study aimed mainly to investigate this temporal dilation effect of BM signals in Parkinson's disease (PD patients. We used the temporal dilation effect as an implicit measure of visual processing of BM. In all, 32 PD patients (under off-therapy conditions and 32 healthy controls (HCs participated in our study. In each trial, an upright BM sequence and an inverted BM sequence were presented within an interval in the center of the screen. We tested both canonical and scrambled BM sequences; the scrambled ones were generated by disturbing the global configuration of the canonical ones but preserving exactly the same local motion components. Observers were required to make a verbal two-alternative forced choice response to indicate which interval (the first or the second appeared longer. Statistical analyses were conducted on the points of subjective equality (PSEs. We found that the temporal dilation effect was significantly reduced for PD patients compared with HCs in both canonical and scrambled BM conditions. Moreover, no temporal dilation effects of scrambled BM were shown in both early- and late-stage PD patients, while the temporal dilation effect of canonical BM was relatively preserved in the early stages.

  18. Hardness and Elastic Modulus on Six-Fold Symmetry Gold Nanoparticles

    Science.gov (United States)

    Ramos, Manuel; Ortiz-Jordan, Luis; Hurtado-Macias, Abel; Flores, Sergio; Elizalde-Galindo, José T.; Rocha, Carmen; Torres, Brenda; Zarei-Chaleshtori, Maryam; Chianelli, Russell R.

    2013-01-01

    The chemical synthesis of gold nanoparticles (NP) by using gold (III) chloride trihydrate (HAuCl∙3H2O) and sodium citrate as a reducing agent in aqueous conditions at 100 °C is presented here. Gold nanoparticles areformed by a galvanic replacement mechanism as described by Lee and Messiel. Morphology of gold-NP was analyzed by way of high-resolution transmission electron microscopy; results indicate a six-fold icosahedral symmetry with an average size distribution of 22 nm. In order to understand the mechanical behaviors, like hardness and elastic moduli, gold-NP were subjected to nanoindentation measurements—obtaining a hardness value of 1.72 GPa and elastic modulus of 100 GPa in a 3–5 nm of displacement at the nanoparticle’s surface. PMID:28809302

  19. H∞ /H2 model reduction through dilated linear matrix inequalities

    DEFF Research Database (Denmark)

    Adegas, Fabiano Daher; Stoustrup, Jakob

    2012-01-01

    This paper presents sufficient dilated linear matrix inequalities (LMI) conditions to the $H_{infty}$ and $H_{2}$ model reduction problem. A special structure of the auxiliary (slack) variables allows the original model of order $n$ to be reduced to an order $r=n/s$ where $n,r,s in field{N}$. Arb......This paper presents sufficient dilated linear matrix inequalities (LMI) conditions to the $H_{infty}$ and $H_{2}$ model reduction problem. A special structure of the auxiliary (slack) variables allows the original model of order $n$ to be reduced to an order $r=n/s$ where $n,r,s in field...... not satisfactorily approximates the original system, an iterative algorithm based on dilated LMIs is proposed to significantly improve the approximation bound. The effectiveness of the method is accessed by numerical experiments. The method is also applied to the $H_2$ order reduction of a flexible wind turbine...

  20. Pulmonary artery dilatation: an overlooked mechanism for angina pectoris.

    Science.gov (United States)

    Ginghina, Carmen; Popescu, Bogdan A; Enache, Roxana; Ungureanu, Catalina; Deleanu, Dan; Platon, Pavel

    2008-07-01

    Dilatation of the pulmonary artery may lead to the compression of adjacent structures. Of those, the extrinsic compression of the left main coronary artery is the most worrisome. We present the case of a 48-year-old woman who was diagnosed with pulmonary artery dilatation due to severe, thromboembolic pulmonary hypertension. She also had angina and coronary angiography revealed a 70% ostial stenosis of the left main coronary artery. The presence of this isolated lesion in a young woman without risk factors for atherosclerosis suggests extrinsic compression of the left main coronary artery by the dilated pulmonary artery as the likely mechanism. The patient underwent direct stenting of the left main coronary stenosis with a good result.

  1. Dilatancy and compaction effects on the submerged granular column collapse

    Science.gov (United States)

    Wang, Chun; Wang, Yongqi; Peng, Chong; Meng, Xiannan

    2017-10-01

    The effects of dilatancy on the collapse dynamics of granular materials in air or in a liquid are studied experimentally and numerically. Experiments show that dilatancy has a critical effect on the collapse of granular columns in the presence of an ambient fluid. Two regimes of the collapse, one being quick and the other being slow, are observed from the experiments and the underlying reasons are analyzed. A two-fluid smoothed particle hydrodynamics model, based on the granular-fluid mixture theory and the critical state theory, is employed to investigate the complex interactions between the solid particles and the ambient water. It is found that dilatancy, resulting in large effective stress and large frictional coefficient between solid particles, helps form the slow regime. Small permeability, representing large inter-phase drag force, also retards the collapse significantly. The proposed numerical model is capable of reproducing these effects qualitatively.

  2. Analysis of the equivalent indenter concept used to extract Young’s modulus from a nano-indentation test: some new insights into the Oliver–Pharr method

    DEFF Research Database (Denmark)

    Andriollo, Tito; Thorborg, Jesper; Hattel, Jesper Henri

    2017-01-01

    's elastic solution which is formally valid only for indentation into a flat surface. This allows for formulating the problem of extracting Young's modulus from the unloading curve as an optimization problem. However, it is proved that the latter does not have a unique solution, due to the particular...

  3. Robust design of dilation and erosion CNN for gray scale image

    Science.gov (United States)

    Zhang, Xiaoliang; Min, Lequan; Li, Min

    2015-12-01

    The cellular neural/nonlinear network (CNN) is a powerful tool for image and video signal processing, as well as robotic and biological visions. The designs for CNN templates are one of the important issues for the practical applications of CNNs. This paper combines two CNN to implement the Dilation CNNs and Erosion CNN for gray scale images and proposes two theorems of robustness designs. The parameters of the templates can range between a hyper plane and a hyper surface in the first quartile. The simulations have been given. The results show the effectiveness of the theoretical results to be implemented in computer simulations.

  4. Curl-Based Finite Element Reconstruction of the Shear Modulus Without Assuming Local Homogeneity: Time Harmonic Case.

    Science.gov (United States)

    Honarvar, Mohammad; Sahebjavaher, Ramin; Sinkus, Ralph; Rohling, Robert; Salcudean, Septimiu E

    2013-12-01

    In elasticity imaging, the shear modulus is obtained from measured tissue displacement data by solving an inverse problem based on the wave equation describing the tissue motion. In most inversion approaches, the wave equation is simplified using local homogeneity and incompressibility assumptions. This causes a loss of accuracy and therefore imaging artifacts in the resulting elasticity images. In this paper we present a new curl-based finite element method inversion technique that does not rely upon these simplifying assumptions. As done in previous research, we use the curl operator to eliminate the dilatational term in the wave equation, but we do not make the assumption of local homogeneity. We evaluate our approach using simulation data from a virtual tissue phantom assuming time harmonic motion and linear, isotropic, elastic behavior of the tissue. We show that our reconstruction results are superior to those obtained using previous curl-based methods with homogeneity assumption. We also show that with our approach, in the 2-D case, multi-frequency measurements provide better results than single-frequency measurements. Experimental results from magnetic resonance elastography of a CIRS elastography phantom confirm our simulation results and further demonstrate, in a quantitative and repeatable manner, that our method is accurate and robust.

  5. Shared Genetic Predisposition in Peripartum and Dilated Cardiomyopathies.

    Science.gov (United States)

    Ware, James S; Li, Jian; Mazaika, Erica; Yasso, Christopher M; DeSouza, Tiffany; Cappola, Thomas P; Tsai, Emily J; Hilfiker-Kleiner, Denise; Kamiya, Chizuko A; Mazzarotto, Francesco; Cook, Stuart A; Halder, Indrani; Prasad, Sanjay K; Pisarcik, Jessica; Hanley-Yanez, Karen; Alharethi, Rami; Damp, Julie; Hsich, Eileen; Elkayam, Uri; Sheppard, Richard; Kealey, Angela; Alexis, Jeffrey; Ramani, Gautam; Safirstein, Jordan; Boehmer, John; Pauly, Daniel F; Wittstein, Ilan S; Thohan, Vinay; Zucker, Mark J; Liu, Peter; Gorcsan, John; McNamara, Dennis M; Seidman, Christine E; Seidman, Jonathan G; Arany, Zoltan

    2016-01-21

    Background Peripartum cardiomyopathy shares some clinical features with idiopathic dilated cardiomyopathy, a disorder caused by mutations in more than 40 genes, including TTN, which encodes the sarcomere protein titin. Methods In 172 women with peripartum cardiomyopathy, we sequenced 43 genes with variants that have been associated with dilated cardiomyopathy. We compared the prevalence of different variant types (nonsense, frameshift, and splicing) in these women with the prevalence of such variants in persons with dilated cardiomyopathy and with population controls. Results We identified 26 distinct, rare truncating variants in eight genes among women with peripartum cardiomyopathy. The prevalence of truncating variants (26 in 172 [15%]) was significantly higher than that in a reference population of 60,706 persons (4.7%, P=1.3×10(-7)) but was similar to that in a cohort of patients with dilated cardiomyopathy (55 of 332 patients [17%], P=0.81). Two thirds of identified truncating variants were in TTN, as seen in 10% of the patients and in 1.4% of the reference population (P=2.7×10(-10)); almost all TTN variants were located in the titin A-band. Seven of the TTN truncating variants were previously reported in patients with idiopathic dilated cardiomyopathy. In a clinically well-characterized cohort of 83 women with peripartum cardiomyopathy, the presence of TTN truncating variants was significantly correlated with a lower ejection fraction at 1-year follow-up (P=0.005). Conclusions The distribution of truncating variants in a large series of women with peripartum cardiomyopathy was remarkably similar to that found in patients with idiopathic dilated cardiomyopathy. TTN truncating variants were the most prevalent genetic predisposition in each disorder.

  6. Shear Elastic Modulus on Patellar Tendon Captured from Supersonic Shear Imaging: Correlation with Tangent Traction Modulus Computed from Material Testing System and Test-Retest Reliability.

    Science.gov (United States)

    Zhang, Zhi Jie; Fu, Siu Ngor

    2013-01-01

    Characterization of the elastic properties of a tendon could enhance the diagnosis and treatment of tendon injuries. The purpose of this study was to examine the correlation between the shear elastic modulus on the patellar tendon captured from a Supersonic Shear Imaging (SSI) and the tangent traction modulus computed from a Material testing system (MTS) on 8 fresh patellar pig tendons (Experiment I). Test-retest reliability of the shear elastic modulus captured from the SSI was established in Experiment II on 22 patellar tendons of 11 healthy human subjects using the SSI. Spearman Correlation coefficients for the shear elastic modulus and tangent traction modulus ranged from 0.82 to 1.00 (all p<0.05) on the 8 tendons. The intra and inter-operator reliabilities were 0.98 (95% CI: 0.93-0.99) and 0.97 (95% CI: 0.93-0.98) respectively. The results from this study demonstrate that the shear elastic modulus of the patellar tendon measured by the SSI is related to the tangent traction modulus quantified by the MTS. The SSI shows good intra and inter-operator repeatability. Therefore, the present study shows that SSI can be used to assess elastic properties of a tendon.

  7. Passive urethral resistance to dilation in healthy women

    DEFF Research Database (Denmark)

    Bagi, P; Thind, P; Nordsten, M

    1995-01-01

    The dynamic urethral pressure response to a simulated urine ingression was studied at the bladder neck, in the high pressure zone, and in the distal urethra in 10 healthy female volunteers. The pressure response was characterised by a steep pressure increase simulataneous with the urethral dilation...... at equilibrium, P alpha and P beta express the decline in pressure, and tau alpha and tau beta are time constants. The size of the pressure response proved highly dependent on velocity and size of dilation as well as urethral site of measurement, with the maximum values in the high pressure zone. The time...

  8. Improved test of time dilation in special relativity.

    Science.gov (United States)

    Saathoff, G; Karpuk, S; Eisenbarth, U; Huber, G; Krohn, S; Muñoz Horta, R; Reinhardt, S; Schwalm, D; Wolf, A; Gwinner, G

    2003-11-07

    An improved test of time dilation in special relativity has been performed using laser spectroscopy on fast ions at the heavy-ion storage-ring TSR in Heidelberg. The Doppler-shifted frequencies of a two-level transition in 7Li+ ions at v=0.064c have been measured in the forward and backward direction to an accuracy of Deltanu/nu=1 x 10(-9) using collinear saturation spectroscopy. The result confirms the relativistic Doppler formula and sets a new limit of 2.2 x 10(-7) for deviations from the time dilation factor gamma(SR)=(1-v2/c2)(-1/2).

  9. A Rare Occurance with Epidermolysis Bullosa Disease: Dilated Cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Derya Cimen

    2014-02-01

    Full Text Available Epidermolysis bullosa is a congenital and herediter vesiculobullous disease. Dystrophic form of this disease is characterized by severe malnutrition, failure to thrive, adhesions at fingers, joint contractures related with the formation of scar tissues, carcinoma of the skin, anemia, hipoalbuminemia, wound enfections and sepsis. Rarely, mortal dilated cardiomyopathy may occur in patients. In this report we present a 13 year-old pediatric patient with dilated cardiomyopathy, clinically diagnosed with Epidermolysis bullosa as well as a review of recent related literature.

  10. Mixed Mode cohesive law with interface dilatation

    DEFF Research Database (Denmark)

    Sørensen, Bent F.; Goutianos, Stergios

    2014-01-01

    Experimental investigations of adhesive joints and fibre composites have shown that under Mode II cracking, the fracture process induces a displacement normal to the fracture plane. This effect can be attributed e.g. to roughness of the fracture surface under dominating tangential crack face disp...... is implemented in the commercial finite element program Abaqus. The model is validated and tested against experimental results under various mode mixities. © 2013 Elsevier Ltd. All rights reserved....

  11. Dilated uropathies in children; Dilatation des reins et voies urinaires chez l`enfant

    Energy Technology Data Exchange (ETDEWEB)

    Bouissou, F. [Centre Hospitalier Universitaire Purpan, 31 - Toulouse (France)

    1995-12-31

    These uropathies are frequent in children and are often diagnosed by ante-natal ultrasound examination. The dilatation, hydronephrosis or uretero-hydro-nephrosis may be due to a large pattern of malformations, either anatomical dysplasia, vesico-ureteric reflux or obstruction of the pelvi-ureteric junction, of the vesical-ureteric junction or due to a chronic urethral obstruction. The investigations must determine the exact urinary tract abnormalities, the renal function and the uro-dynamic change. They are guided by the ultrasound findings and cystography. In obstructive malformation, the MAG3 renogram with furosemide test is the best way to precise the uro-dynamic status, but it requires a careful technique in children and its interpretation is sometimes equivocal. DMSA scan is very useful to give precise separate kidney function and to follow the maturational change with age. All the results must be carefully analysed ; the final therapeutic decision and specially surgery is dependent of the type of uropathy and its natural history. In many cases, surgical treatment is only indicated after a longer follow-up and repeated evaluations. (authors). 11 refs., 2 figs.

  12. Shear Modulus for Nonisotropic, Open-Celled Foams Using a General Elongated Kelvin Foam Model

    Science.gov (United States)

    Sullivan, Roy M.; Ghosn, Louis J.

    2008-01-01

    An equation for the shear modulus for nonisotropic, open-celled foams in the plane transverse to the elongation (rise) direction is derived using an elongated Kelvin foam model with the most general geometric description. The shear modulus was found to be a function of the unit cell dimensions, the solid material properties, and the cell edge cross-section properties. The shear modulus equation reduces to the relation derived by others for isotropic foams when the unit cell is equiaxed.

  13. Joint Use of Constant Modulus and Least Squares Criteria in Linearly-Constrained Communication Arrays

    Directory of Open Access Journals (Sweden)

    V. I. Djigan

    2007-12-01

    Full Text Available This paper considers the application of the linear constraints and RLS inverse QR decomposition in adaptive arrays based on constant modulus criterion. The computational procedures of adaptive algorithms are presented. Linearly constrained least squares adaptive arrays, constant modulus adaptive arrays and linearly constrained constant modulus adaptive arrays are compared via simulation. It is demonstrated, that a constant phase shift in the array output signal, caused by desired signal orientation and array weights, is compensated in a simple way in linearly constrained constant modulus adaptive arrays.

  14. Case Report Percutaneous Dilational Tracheostomy A bed side ...

    African Journals Online (AJOL)

    Introduction: Tracheostomy is one of the most commonly performed procedures in critically ill patients. Percutaneous dilatational tracheostomy (PDT), according to ciaglias technique described in 1985, has become the most popular technique for percutaneous tracheostomy and is demonstrably as safe as surgical.

  15. Cervical ripening with prostaglandin gel and hygroscopic dilators.

    Science.gov (United States)

    Hibbard, J U; Shashoua, A; Adamczyk, C; Ismail, M

    1998-01-01

    OBJECTIVE: To study the effectiveness and morbidity of adding hygroscopic cervical dilators to prostaglandin gel for cervical ripening and labor induction. STUDY DESIGN: Patients of at least 34 weeks' gestation with a medical indication for induction of labor and with a modified Bishop score of 5 or less were randomized to receive either prostaglandin gel or prostaglandin gel with hygroscopic cervical dilators. Primary outcomes were time to delivery, change in cervical score, and infection. Secondary outcomes included cesarean delivery rate and deliveries before 24 hours of induction. Continuous variables were analyzed by Wilcoxon sum rank test and categorical data by chi-square or Fisher exact test, with P intracervical prostaglandin alone and 23 patients received intracervical prostaglandin plus hygroscopic dilators. No demographic differences were noted between the groups. After six hours of ripening, the combined group achieved a greater change in Bishop score (3.6 vs. 2.1, P = 0.007) and tended to have a shorter induction time (21.7 vs. 26.4 hours, P = 0.085). The combined therapy group had a higher infection rate than the prostaglandin-only group (59% vs. 12%, P = 0.003). CONCLUSION: Combining cervical dilators with prostaglandin gel provides more effective cervical ripening and a more rapid induction to delivery interval than prostaglandin alone but with a significant and prohibitive rate of infection. PMID:9678143

  16. Non-obstructive cecal dilatation and perforation after cesarean section

    DEFF Research Database (Denmark)

    Sperling, Lene; Schantz, A L; Toftager-Larsen, K

    1990-01-01

    A case of non-obstructive cecal dilatation and perforation after cesarean section is reported, with a review of the literature on the diagnosis and management of this entity. Fifteen cases have been described. Attention is called to this rare complication and to the accompanying pseudo...

  17. 28. Critical pulmonary valve stenosis: Medical management beyond balloon dilation

    Directory of Open Access Journals (Sweden)

    Muhammad Arif Khan

    2015-10-01

    Conclusion: Phentolamine and/or Captopril have a therapeutic role in neonates with critical PVS who remain oxygen dependent after balloon dilation. Both medicationslead to vasodilatation of pulmonary and systemic vascularity. They facilitate inflowto the right ventricle. Right to left shunt across a PFO or/ ASD minimizesand saturation improves leading to a significantreduction in length of hospitalization.

  18. Gravitational time dilation and length contraction in fields exterior to ...

    African Journals Online (AJOL)

    Here, we use our new metric tensor exterior to a massiv3e oblate spheroid to study the gravitational phenomena of time dilation and length contraction. It turns out most profoundly that, the above phenomena hold good in the gravitational field exterior to an oblate spheroid. We then use the oblate spheroidal Earth to ...

  19. Migraine pain associated with middle cerebral artery dilatation

    DEFF Research Database (Denmark)

    Friberg, L; Olesen, J; Iversen, Helle Klingenberg

    1991-01-01

    returned to normal after treatment with sumatriptan and recovery. Since rCBF in the MCA supply territory was unaffected, the lower velocity can be explained only by dilatation of the MCA. The mean MCA diameter increase was estimated to be 20%. Thus, headache was associated with intracranial large arterial...

  20. unilateral idiopathic dilated episcleral vein with secondary open ...

    African Journals Online (AJOL)

    TAIBAT OTULANA

    Olabisi Onabanjo University, Sagamu, Ogun State. Nigeria. Nigerian Journal of Ophthalmology 2008; 16(1): 20-22. Unilateral Idiopathic Dilated Episcleral Vein with Secondary. Open Angle Glaucoma (Radius–Maumenee Syndrome) in an. African – A case report and literature review. TO Otulana, OO Onabolu, VO Fafiolu.

  1. Pattern of cervical dilatation among parturients in Ilorin, Nigeria

    African Journals Online (AJOL)

    8, July-September, 2009. Pattern of cervical dilatation among parturients in. Ilorin, Nigeria. Munir'deen A. Ijaiya, Abiodun P. Aboyeji, Olurotimi O. Fakeye, Olayinka R. Balogun,. Duum C. Nwachukwu, Moses O. Abiodun. Department of Obstetrics and Gynaecology, University of Ilorin Teaching Hospital, Maternity Hospital ...

  2. Thallium scintigraphy for the prognosis of idiopathic dilated cardiomyopathy

    International Nuclear Information System (INIS)

    Yabe, Toshikazu; Furuno, Takashi; Kitaoka, Hiroaki; Matsumura, Yoshihisa; Yamasaki, Naohito; Doi, Yoshinori

    2002-01-01

    This study evaluated the significance of perfusion defects demonstrated by thallium-201 and age in the prognosis of patients with idiopathic dilated cardiomyopathy. Seventy-four dilated cardiomyopathy patients underwent thallium scintigraphy as well as clinical and hemodynamic examination. Abnormal perfusion defects were present in 23 of 38 patients aged <60 years (61%) and in 26 of 36 elderly patients aged ≥60 years (72%; NS). Univariate analysis showed that such perfusion defects were a significant predictor of cardiac death only in patients aged <60 years (p=0.015). Stepwise discriminant analysis also revealed that perfusion defects were a significant predictor in patients aged <60 years (Wilks' lambda 0.499, chi-square test 20.2, p=0.003). Perfusion defects were not more important than the history of syncope or stroke in elderly dilated cardiomyopathy patients. Twenty-one patients died of disease-related causes during 58±43 months. The five-year survival rate was better in patients aged <60 years without than in those with perfusion defects (100% vs 58.4%, respectively), but not affected in patients aged ≥60 years (66.7% vs 62.2%). Thallium scintigraphy is valuable for the prognosis of patients with dilated cardiomyopathy aged <60 years who are usually candidates for heart transplantation. Absence of thallium perfusion defects may indicate good long-term prognosis. (author)

  3. Gallbladder duplication masquerading as a dilated common bile ...

    African Journals Online (AJOL)

    A duplicate gall bladder was diagnosed at laparoscopy, having been erroneously diagnosed on ultrasonography as a dilated common bile duct with choledocholithiasis. Gallbladder duplication is a congenital abnormality with a rare incidence, occuring in approximately 1 in 4 000 births and 0.020% in al large autopsy ...

  4. Dilatancy of Shear Transformations in a Colloidal Glass

    Science.gov (United States)

    Lu, Y. Z.; Jiang, M. Q.; Lu, X.; Qin, Z. X.; Huang, Y. J.; Shen, J.

    2018-01-01

    Shear transformations, as fundamental rearrangement events operating in local regions, hold the key of plastic flow of amorphous solids. Despite their importance, the dynamic features of shear transformations are far from clear, which is the focus of the present study. Here, we use a colloidal glass under shear as the prototype to directly observe the shear-transformation events in real space. By tracing the colloidal-particle rearrangements, we quantitatively determine two basic properties of shear transformations: local shear strain and dilatation (or free volume). It is revealed that the local free volume undergoes a significantly temporary increase prior to shear transformations, eventually leading to a jump of local shear strain. We clearly demonstrate that shear transformations have no memory of the initial free volume of local regions. Instead, their emergence strongly depends on the dilatancy ability of these local regions, i.e., the dynamic creation of free volume. More specifically, the particles processing the high dilatancy ability directly participate in subsequent shear transformations. These results experimentally enrich Argon's statement about the dilatancy nature of shear transformations and also shed insight into the structural origin of amorphous plasticity.

  5. Arborescent vascular dilatation mimicking Lichtenberg figures from lightning.

    Science.gov (United States)

    Tempark, Therdpong; Iwasaki, Julie; Shwayder, Tor

    2014-01-01

    The clinical presentation of arborizing vascular dilatation can resemble Lichtenberg figures from lightning. Both have a feather-like or ferning pattern. We report an interesting case of pressure-induced vasodilatation (PIV) caused by temporary vascular occlusion from jeans buttons. © 2014 Wiley Periodicals, Inc.

  6. Thallium scintigraphy for the prognosis of idiopathic dilated cardiomyopathy

    Energy Technology Data Exchange (ETDEWEB)

    Yabe, Toshikazu; Furuno, Takashi; Kitaoka, Hiroaki; Matsumura, Yoshihisa; Yamasaki, Naohito; Doi, Yoshinori [Kochi Medical School, Nankoku (Japan)

    2002-11-01

    This study evaluated the significance of perfusion defects demonstrated by thallium-201 and age in the prognosis of patients with idiopathic dilated cardiomyopathy. Seventy-four dilated cardiomyopathy patients underwent thallium scintigraphy as well as clinical and hemodynamic examination. Abnormal perfusion defects were present in 23 of 38 patients aged <60 years (61%) and in 26 of 36 elderly patients aged {>=}60 years (72%; NS). Univariate analysis showed that such perfusion defects were a significant predictor of cardiac death only in patients aged <60 years (p=0.015). Stepwise discriminant analysis also revealed that perfusion defects were a significant predictor in patients aged <60 years (Wilks' lambda 0.499, chi-square test 20.2, p=0.003). Perfusion defects were not more important than the history of syncope or stroke in elderly dilated cardiomyopathy patients. Twenty-one patients died of disease-related causes during 58{+-}43 months. The five-year survival rate was better in patients aged <60 years without than in those with perfusion defects (100% vs 58.4%, respectively), but not affected in patients aged {>=}60 years (66.7% vs 62.2%). Thallium scintigraphy is valuable for the prognosis of patients with dilated cardiomyopathy aged <60 years who are usually candidates for heart transplantation. Absence of thallium perfusion defects may indicate good long-term prognosis. (author)

  7. Balloon dilatation of isolated severe tricuspid valve stenosis

    Directory of Open Access Journals (Sweden)

    Rajeev Bhardwaj

    2015-12-01

    Full Text Available Tricuspid valve stenosis is mostly rheumatic in origin. It almost always occurs in association with mitral valve disease. There are only few case reports of isolated tricuspid valve stenosis. We report a case of isolated tricuspid valve stenosis, which was treated with balloon dilatation.

  8. Balloon dilatation of isolated severe tricuspid valve stenosis

    OpenAIRE

    Bhardwaj, Rajeev; Sharma, Rajesh

    2015-01-01

    Tricuspid valve stenosis is mostly rheumatic in origin. It almost always occurs in association with mitral valve disease. There are only few case reports of isolated tricuspid valve stenosis. We report a case of isolated tricuspid valve stenosis, which was treated with balloon dilatation.

  9. Impedance and modulus spectroscopic study of nano hydroxyapatite

    Science.gov (United States)

    Jogiya, B. V.; Jethava, H. O.; Tank, K. P.; Raviya, V. R.; Joshi, M. J.

    2016-05-01

    Hydroxyapatite (Ca10 (PO4)6 (OH)2, HAP) is the main inorganic component of the hard tissues in bones and also important material for orthopedic and dental implant applications. Nano HAP is of great interest due to its various bio-medical applications. In the present work the nano HAP was synthesized by using surfactant mediated approach. Structure and morphology of the synthesized nano HAP was examined by the Powder XRD and TEM. Impedance study was carried out on pelletized sample in a frequency range of 100Hz to 20MHz at room temperature. The variation of dielectric constant, dielectric loss, and a.c. conductivity with frequency of applied field was studied. The Nyquist plot as well as modulus plot was drawn. The Nyquist plot showed two semicircle arcs, which indicated the presence of grain and grain boundary effect in the sample. The typical behavior of the Nyquist plot was represented by equivalent circuit having two parallel RC combinations in series.

  10. Polymerization Shrinkage and Flexural Modulus of Flowable Dental Composites

    Directory of Open Access Journals (Sweden)

    Janaína Cavalcanti Xavier

    2010-09-01

    Full Text Available Linear polymerization shrinkage (LPS, flexural strength (FS and modulus of elasticity (ME of low-viscosity resin composites (Admira Flow™, Grandio Flow™/VOCO; Filtek Z350 Flow™/3M ESPE; Tetric Flow™/Ivoclar-Vivadent was evaluated using a well-established conventional micro-hybrid composite as a standard (Filtek Z250™/3M ESPE. For the measurement of LPS, composites were applied to a cylindrical metallic mould and polymerized (n = 8. The gap formed at the resin/mould interface was observed using SEM (1500×. For FS and ME, specimens were prepared according to the ISO 4049 specifications (n = 10. Statistical analysis of the data was performed with one-way ANOVA and the Tukey test. The conventional resin presented significantly lower LPS associated with high FS and ME, but only the ME values of the conventional resin differed significantly from the low-viscosity composites. The relationship between ME and LPS of low-viscosity resin composites when used as restorative material is a critical factor in contraction stress relief and marginal leakage.

  11. Rolling, slip and traction measurements on low modulus materials

    Science.gov (United States)

    Tevaarwerk, J. L.

    1985-01-01

    Traction and wear tests were performed on six low modulus materials (LMM). Three different traction tests were performed to determine the suitability of the material for use as traction rollers. These were the rolling, slip and endurance traction tests. For each material the combination LMM on LMM and LMM on steel were evaluated. Rolling traction test were conducted to determine the load - velocity limits, the rolling traction coefficient of the materials and to establish the type of failures that would result when loading beyond the limit. It was found that in general a simple constant rolling traction coefficient was enough to describe the results of all the test. The slip traction tests revealed that the peak traction coefficients were considerably higher than for lubricated traction contacts. The endurance traction tests were performed to establish the durability of the LMM under conditions of prolonged traction. Wear measurements were performed during and after the test. Energetic wear rates were determined from the wear measurements conducted in the endurance traction tests. These values show that the roller wear is not severe when reasonable levels of traction are transmitted.

  12. Effect of curing light emission spectrum on the nanohardness and elastic modulus of two bulk-fill resin composites.

    Science.gov (United States)

    Issa, Yaser; Watts, David C; Boyd, Daniel; Price, Richard B

    2016-04-01

    To determine the nanohardness and elastic moduli of two bulk-fill resin based composites (RBCs) at increasing depths from the surface and increasing distances laterally from the center after light curing. Two bulk-fill dental RBCs: Tetric EvoCeram Bulk Fill (TECBF) and Filtek Bulk Fill Flowable (FBFF) were light cured in a metal mold with a 6mm diameter and a 10mm long semi-circular notch. The RBCs were photo-polymerized for 10s using a light emitting diode (LED) Bluephase Style curing light, with the original light probe that lacked the homogenizer. This light has two blue light and one violet light LED emitters. By changing the probe orientation over the mold, the light output from only two LEDs reached the RBC. Measurements were made using: (i) the light from one violet and one blue LED, and (ii) the light from the two blue LEDs. Five specimens of each RBC were made using each LED orientation (total 20 specimens). Specimens were then stored in the dark at 37°C for 24h. Fifty indents were made using an Agilent G200 nanoindentor down to 4mm from the surface and 2.5mm right and left of the centerline. The results were analyzed (alpha=0.05) using multiple paired-sample t-tests, ANOVA, Bonferroni post-hoc tests, and Pearson correlations. The elastic modulus and nanohardness varied according to the depth and the distance from the centerline. For TECBF, no significant difference was found between the spatial variations in the elastic modulus or hardness values when violet-blue or blue-blue LEDs were used. For FBFF, the elastic modulus and nanohardness on the side exposed to the violet emitter were significantly less than the side exposed to the blue emitter. A strong correlation between nanohardness and elastic modulus was found in all groups (r(2)=0.9512-0.9712). Resin polymerization was not uniform throughout the RBC. The nanohardness and elastic modulus across two RBC materials were found to decline differently according to the orientation of the violet and blue

  13. Dilation volumes of sets of bounded perimeter

    DEFF Research Database (Denmark)

    Kiderlen, Markus; Rataj, Jan

    , this derivative coincides up to sign with the directional derivative of the covariogram of A in direction u. By known results for the covariogram, this derivative can therefore be expressed by the cosine transform of the surface area measure of A. We extend this result to sets Q that are at most countable and use...... it to determine the derivative of the contact distribution function of a stationary random closed set at zero. A variant for uncountable Q is given, too. The proofs are based on approximation of the characteristic function of A by smooth functions of bounded variation and showing corresponding formulas for them....

  14. Interfacial dynamic and dilational rheology of polyelectrolyte/surfactant two-component nanoparticle systems at air–water interface

    International Nuclear Information System (INIS)

    Tong, L.J.; Bao, M.T.; Li, Y.M.; Gong, H.Y.

    2014-01-01

    Graphical abstract: - Highlights: • DTAB/PSS mixture can self-assemble nanoparticles in bulk solution. • The nanoparticles can adsorb at the interface forming a nanoparticle monolayer. • The nanoparticles spread at the interface undergo a disassembly process with time. • The nanoparticle monolayer presents peculiar dilational viscoelastic behavior. - Abstract: The interfacial characteristics of nanoparticles and consequent inter-particle interactions at the interface are poorly understood. In this work, the interfacial dynamic and corresponding dilational surface rheology of self-assembled polyelectrolyte/surfactant nanoparticles at the air–water interface are characterized. The nanoparticles are prepared from dodecyltrimethylammonium (DTAB) and poly (sodium 4-styrene-sulfonate) (PSS) by mixing them in aqueous solution. The interfacial dynamic characteristics have been carried out by comparing the surface pressure with the dilational rheological response of these nanoparticles at interface. The results indicate that this type of nanoparticles can adsorb at the interface forming a nanoparticle monolayer, which leads to the surface tension decreased markedly. The dependence of surface pressure on time shows the instability and disassembly process of nanoparticles at the interface. On the basis of these observations, it is proposed that the nanoparticles undergo a dynamic process that interface induced nanoparticles disassembly into DTAB/PSS complexes. The presence of PSS in the subphase can promote the process of nanoparticles disassembly. A transition point in dilational elasticity and viscosity response of the nanoparticles versus oscillation frequency further validate the micro dynamic process of nanoparticles and the formation of polyelectrolyte/surfactant complex monolayer at the interface

  15. A predictive model for canine dilated cardiomyopathy—a meta-analysis of Doberman Pinscher data

    Directory of Open Access Journals (Sweden)

    Siobhan Simpson

    2015-03-01

    Full Text Available Dilated cardiomyopathy is a prevalent and often fatal disease in humans and dogs. Indeed dilated cardiomyopathy is the third most common form of cardiac disease in humans, reported to affect approximately 36 individuals per 100,000 individuals. In dogs, dilated cardiomyopathy is the second most common cardiac disease and is most prevalent in the Irish Wolfhound, Doberman Pinscher and Newfoundland breeds. Dilated cardiomyopathy is characterised by ventricular chamber enlargement and systolic dysfunction which often leads to congestive heart failure. Although multiple human loci have been implicated in the pathogenesis of dilated cardiomyopathy, the identified variants are typically associated with rare monogenic forms of dilated cardiomyopathy. The potential for multigenic interactions contributing to human dilated cardiomyopathy remains poorly understood. Consistent with this, several known human dilated cardiomyopathy loci have been excluded as common causes of canine dilated cardiomyopathy, although canine dilated cardiomyopathy resembles the human disease functionally. This suggests additional genetic factors contribute to the dilated cardiomyopathy phenotype.This study represents a meta-analysis of available canine dilated cardiomyopathy genetic datasets with the goal of determining potential multigenic interactions relating the sex chromosome genotype (XX vs. XY with known dilated cardiomyopathy associated loci on chromosome 5 and the PDK4 gene in the incidence and progression of dilated cardiomyopathy. The results show an interaction between known canine dilated cardiomyopathy loci and an unknown X-linked locus. Our study is the first to test a multigenic contribution to dilated cardiomyopathy and suggest a genetic basis for the known sex-disparity in dilated cardiomyopathy outcomes.

  16. Dobutamine Stress Echocardiography in Patients with Dilated Cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Miloradovic Vladimir

    2016-06-01

    Full Text Available A clear distinction between two of the most common forms of dilated cardiomyopathy is very important due to their different prediction and therapeutic approaches. Dobutamine stress echocardiography appears to be a noninvasive selection method due to its clear differentiation potential. Major factors influence test interpretation, resulting in a wide interval of diagnostic accuracy for this test. Fraction flow reserve (FFR is a novel invasive method for estimating coronary artery stenosis responsible for myocardium ischaemia. Decisions about lesion significance in coronary blood vessels have thus far been based on angiographic estimations, but this approach is being replaced by FFR measurements, which serve as a new gold standard and involve a noninvasive test. The goal of this study was to clearly differentiate two forms of dilated cardiomyopathies through analysis of the segmented mobility of the left ventricular wall. Fifty patients were analysed: 20 with ischaemic dilated cardiomyopathy, which was confirmed not only through coronary angiography but also functionally through FFR measurement, and 30 patients with nonischaemic dilated cardiomyopathy, which was confirmed by coronary angiography. A standard dobutamine stress echocardiography protocol was implemented. A positive dobutamine stress echocardiography test was defined as the presence of emerging incidents in segment contractility or worsening of existing incidents in at least one segment. Statistically relevant diff erences in the movement dynamics of a number of differently characterised segments during the observed time intervals (ANOVA p=0.000 was noted in both groups of patients, as was variation in the index value of the summarized mobility of the left chamber wall. In patients with ischaemic cardiomyopathies, regional contractility worsened at the maximum dose of dobutamine; in contrast, this feature slightly improved in nonischaemic cardiomyopathy patients. The results indicate

  17. Changes in overall ventricular myocardial architecture in the setting of a porcine animal model of right ventricular dilation.

    Science.gov (United States)

    Agger, Peter; Ilkjær, Christine; Laustsen, Christoffer; Smerup, Morten; Frandsen, Jesper R; Ringgaard, Steffen; Pedersen, Michael; Partridge, John B; Anderson, Robert H; Hjortdal, Vibeke

    2017-11-27

    Chronic pulmonary regurgitation often leads to myocardial dysfunction and heart failure. It is not fully known why secondary hypertrophy cannot fully protect against the increase in wall stress brought about by the increased end-diastolic volume in ventricular dilation. It has been assumed that mural architecture is not deranged in this situation, but we hypothesised that there might be a change in the pattern of orientation of the aggregations of cardiomyocytes, which would contribute to contractile impairment. We created pulmonary valvular regurgitation by open chest, surgical suturing of its leaflets in seven piglets, performing sham operations in seven control animals. Using cardiovascular magnetic resonance imaging after 12 weeks of recovery, we demonstrated significantly increased right ventricular volumes in the test group. After sacrifice, diffusion tensor imaging of their hearts permitted measurement of the orientation of the cardiomyocytes. The helical angles in the right ventricle approached a more circumferential orientation in the setting of right ventricular RV dilation (p = 0.007), with an increased proportion of surface-parallel cardiomyocytes. In contrast, this proportion decreased in the left ventricle. Also in the left ventricle a higher proportion of E3 angles with a value around zero was found, and conversely a lower proportion of angles was found with a numerical higher value. In the dilated right ventricle the proportion of E3 angles around -90° is increased, while the proportion around 90° is decreased. Contrary to traditional views, there is a change in the orientation of both the left ventricular and right ventricular cardiomyocytes subsequent to right ventricular dilation. This will change their direction of contraction and hinder the achievement of normalisation of cardiomyocytic strain, affecting overall contractility. We suggest that the aetiology of the cardiac failure induced by right vetricular dilation may be partly explained

  18. Influence of the Elastic Dilatation of Mining-Induced Unloading Rock Mass on the Development of Bed Separation

    Directory of Open Access Journals (Sweden)

    Weibing Zhu

    2018-03-01

    Full Text Available Understanding how mining-induced strata movement, fractures, bed separation, and ground subsidence evolve is an area of great importance for the underground coal mining industry, particularly for disaster control and sustainable mining. Based on the rules of mining-induced strata movement and stress evolution, accumulative dilatation of mining-induced unloading rock mass is first proposed in this paper. Triaxial unloading tests and theoretical calculation were used to investigate the influence of elastic dilatation of mining-induced unloading rock mass on the development of bed separation in the context of district No. 102 where a layer of super-thick igneous sill exists in the Haizi colliery. It is shown that the elastic dilatation coefficient of mining-induced unloading hard rocks and coal were 0.9~1.0‰ and 2.63‰ respectively under the axial load of 16 MPa, which increased to 1.30~1.59‰ and 4.88‰ when the axial load was 32 MPa. After successively excavating working faces No. 1022 and No. 1024, the elastic dilatation of unloading rock mass was 157.9 mm, which represented approximately 6.3% of the mining height, indicating the elastic dilatation of mining-induced unloading rock mass has a moderate influence on the development of bed separation. Drill hole detection results after grouting, showed that only 0.33 m of the total grouting filling thickness (1.67 m was located in the fracture zone and bending zone, which verified the result from previous drill hole detection that only small bed separation developed beneath the igneous sill. Therefore, it was concluded that the influences of elastic dilatation of mining-induced unloading rock mass and bulking of caved rock mass jointly contributed to the small bed separation space beneath the igneous sill. Since the accurate calculation of the unloading dilatation of rock mass is the fundamental basis for quantitative calculation of bed separation and surface subsidence, this paper is expected

  19. Percutaneous dilatational tracheostomy without fiber optic bronchoscopy-Evaluation of 80 intensive care units cases

    NARCIS (Netherlands)

    J.A. Calvache (Jose Andrés); R.A. Molina García (Rodrigo); A.L. Trochez (Adolfo); J. Benitez (Javier); L.A. Flga (Lucía Arroyo)

    2013-01-01

    textabstractBackground: The development of percutaneous dilatational tracheostomy techniques (PDT) has facilitated the procedure in Intensive Care Units (ICU). Objective: To describe the early intra and post-operative complications in ICU patients requiring percutaneous dilatational tracheostomy

  20. Endoscopic balloon dilatation for Crohn's strictures of the gastrointestinal tract is feasible

    DEFF Research Database (Denmark)

    Karstensen, John Gásdal; Hendel, Jakob; Vilmann, Peter

    2012-01-01

    Despite optimized medical treatment, Crohn´s disease can cause gastrointestinal (GI) strictures, which requires surgical intervention. Lately, endoscopic balloon dilatation has been established as an alternative to surgery. In the following, we report our experiences with endoscopic dilatation...

  1. Non-monotonic size dependence of the elastic modulus of nanocrystalline ZnO embedded in a nanocrystalline silver matrix

    Energy Technology Data Exchange (ETDEWEB)

    Panchal, Vinod; Ghosh, Shankar; Gohil, Smita; Kulkarni, Nilesh; Ayyub, Pushan [Department of Condensed Matter Physics and Materials Science, Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Mumbai-400005 (India)

    2008-08-27

    We present the first high pressure Raman study of nanocrystalline ZnO with different average crystallite sizes. The problem of low Raman signals from nanometer-sized particles was overcome by forming a nanocomposite of Ag and ZnO nanoparticles. The presence of the nanodispersed Ag particles leads to a substantial surface enhancement of the Raman signal from ZnO. We find that the elastic modulus of nanocrystalline ZnO shows a non-monotonic dependence on the crystallite size and suggest that the non-monotonicity arises from an interplay between the elastic properties of the individual grains and the intergranular region.

  2. Contributions crumb rubber in hot mix asphalt to the resilient modulus

    Science.gov (United States)

    Ariyapijati, Raden Hendra; Hadiwardoyo, Sigit Pranowo; Sumabrata, R. Jachrizal

    2017-06-01

    Pavement on the structure of the surface layer receives direct load from the vehicles. Road surfaces are designed to withstand the wear from vehicle loads. Therefore, we need a way to improve the durability of the pavement. Road damage may reduce the life of roads and increase the maintenance costs. The retention rate of road surface material is affected by the environmental conditions, one of them is temperature. To overcome the issues related to temperature, material additives are added to the asphalt mixture. These additive materials would change the binding properties of bitumen and the characteristics of strain and stress before the damage due to repeated traffic loading. Crumb rubber (CR) is a type of polymer additives and thermoplastic elastomers are obtained from scrap tires and rubber waste that is utilized in order to preserve the environment. This study investigated the contribution of the crumb rubber in terms of the value of resilient modulus and resistance to deformation. Hot mix asphalt used was asphalt Pen 60/70, coarse aggregate, fine aggregate and filler. Crumb rubber was made from scrap tire rubber, in the form of fine powder with sieve no. 30 (0.6 mm). CR additive was added to the base asphalt at several rates of 5%, 10%, 15%, and 20% at a temperature of 177° C. The test data used the indirect tensile test with a tool UMATTA at temperatures of 25°, 35°, and 45° C. The test results showed that the levels of crumb rubber on the asphalt decreased the penetration rate, increased the bitumen softening point, and improved the resistance to permanent deformation. The addition of additive materials was evidenced to improve the penetration index, reduce the temperature sensitivity, and increase the viscosity. Subsequently, it can extend the temperature range of viscoelasticity. The contributions of crumb rubber in hot mix asphalt included the increase of the recoverable deformation and the decrease of the value of resilient modulus. This study

  3. Thermodynamic regularities in compressed liquids: II. The reduced bulk modulus

    International Nuclear Information System (INIS)

    Taravillo, Mercedes; Caceres, Mercedes; Nunez, Javier; Baonza, Valentin G

    2006-01-01

    In a previous work, we analysed some regularities found in the behaviour of the thermal expansion coefficient, α p , in compressed liquids. We confirmed that a given liquid presents a characteristic pressure range in which the condition (∂α p /∂T) p =0 is fulfilled within a narrow range of reduced densities. We also found that the density at which the condition (∂α p /∂T) p =0 is satisfied, ρ α , decreases with temperature, a key feature not described before. Earlier studies by other authors suggested that similar regularities are expected for the reduced bulk modulus, B. We present here a detailed analysis of the temperature and density dependence of B from existing experimental results at high pressures. Several liquids have been analysed: argon, krypton, xenon, ethylene, tetrafluoromethane, trifluoromethane, carbon dioxide, carbon disulfide, n-butane, n-hexane, toluene, ethanol, 1-hexanol, m-cresol, and quinoline. We locate that the density ρ B that fulfils the condition (∂B/∂T) ρ =0 occurs at a particular region of the phase diagram, between 3.4 and 2.4 times the critical density of each liquid. Interestingly, the previously found density ρ α is close to ρ B , in a similar region of the reduced phase diagram. However, we note that ρ B typically decreases to a lesser extent with temperature than ρ α . In addition, we have found that ρ B (T) behaves in a parallel fashion for the different liquids, showing larger values of ρ B as the complexity of the molecules increases. These findings provide a strong basis for developing general equation of state models to describe the behaviour of liquids in the high-pressure regime

  4. Thermodynamic regularities in compressed liquids: II. The reduced bulk modulus

    Energy Technology Data Exchange (ETDEWEB)

    Taravillo, Mercedes; Caceres, Mercedes; Nunez, Javier; Baonza, Valentin G [Departamento de Quimica Fisica I, Facultad de Ciencias Quimicas, Universidad Complutense de Madrid, 28040-Madrid (Spain)

    2006-11-15

    In a previous work, we analysed some regularities found in the behaviour of the thermal expansion coefficient, {alpha}{sub p}, in compressed liquids. We confirmed that a given liquid presents a characteristic pressure range in which the condition ({partial_derivative}{alpha}{sub p}/{partial_derivative}T){sub p}=0 is fulfilled within a narrow range of reduced densities. We also found that the density at which the condition ({partial_derivative}{alpha}{sub p}/{partial_derivative}T){sub p}=0 is satisfied, {rho}{sub {alpha}}, decreases with temperature, a key feature not described before. Earlier studies by other authors suggested that similar regularities are expected for the reduced bulk modulus, B. We present here a detailed analysis of the temperature and density dependence of B from existing experimental results at high pressures. Several liquids have been analysed: argon, krypton, xenon, ethylene, tetrafluoromethane, trifluoromethane, carbon dioxide, carbon disulfide, n-butane, n-hexane, toluene, ethanol, 1-hexanol, m-cresol, and quinoline. We locate that the density {rho}{sub B} that fulfils the condition ({partial_derivative}B/{partial_derivative}T){sub {rho}}=0 occurs at a particular region of the phase diagram, between 3.4 and 2.4 times the critical density of each liquid. Interestingly, the previously found density {rho}{sub {alpha}} is close to {rho}{sub B}, in a similar region of the reduced phase diagram. However, we note that {rho}{sub B} typically decreases to a lesser extent with temperature than {rho}{sub {alpha}}. In addition, we have found that {rho}{sub B}(T) behaves in a parallel fashion for the different liquids, showing larger values of {rho}{sub B} as the complexity of the molecules increases. These findings provide a strong basis for developing general equation of state models to describe the behaviour of liquids in the high-pressure regime.

  5. Variation of Hardness and Modulus across thickness of Zr-Cu-Al Metallic Glass Ribbons

    Science.gov (United States)

    Z. Humberto Melgarejo; J.E. Jakes; J. Hwang; Y.E. Kalay; M.J. Kramer; P.M. Voyles; D.S. Stone

    2012-01-01

    We investigate through-thickness hardness and modulus of Zr50Cu45Al5 metallic glass melt-spun ribbon. Because of their thinness, the ribbons are challenging to measure, so we employ a novel nanoindentation based-method to remove artifacts caused by ribbon flexing and edge effects. Hardness and modulus...

  6. Resilient modulus characteristics of soil subgrade with geopolymer additive in peat

    Science.gov (United States)

    Zain, Nasuhi; Hadiwardoyo, Sigit Pranowo; Rahayu, Wiwik

    2017-06-01

    Resilient modulus characteristics of peat soil are generally very low with high potential of deformation and low bearing capacity. The efforts to improve the peat subgrade resilient modulus characteristics is required, one among them is by adding the geopolymer additive. Geopolymer was made as an alternative to replace portland cement binder in the concrete mix in order to promote environmentally friendly, low shrinkage value, low creep value, and fire resistant material. The use of geopolymer to improve the mechanical properties of peat as a road construction subgrade, hence it becomes important to identify the effect of geopolymer addition on the resilient modulus characteristics of peat soil. This study investigated the addition of 0% - 20% geopolymer content on peat soil derived from Ogan Komering Ilir, South Sumatera Province. Resilient modulus measurement was performed by using cyclic triaxial test to determine the resilience modulus model as a function of deviator stresses and radial stresses. The test results showed that an increase in radial stresses did not necessarily lead to an increase in modulus resilient, and on the contrary, an increase in deviator stresses led to a decrease in modulus resilient. The addition of geopolymer in peat soil provided an insignificant effect on the increase of resilient modulus value.

  7. Elastic modulus correction term in creep activation energies: applied to oxide dispersion strengthened superalloy

    International Nuclear Information System (INIS)

    Malu, M.; Tien, J.K.

    1975-01-01

    Creep properties of Inconel alloy MA 753 were studied. It was found that below 1500 0 F, where elastic modulus is weakly dependent upon temperature, the modulus correction term to creep activation energy is small. Accordingly, for superalloy systems such as INCONEL alloy MA 753 and Mar-M 200, which show high apparent creep activation energies at this temperature, modulus corrections are unimportant and their true activation energies remain high. In contrast, at very high temperatures, as a consequence of the high temperature values and the sharper changes in the slope of the young modulus vs. temperature curve, the elastic modulus correction term can be significant--it is found to be about -142 kcal/ mole for INCONEL alloy MA 753 at 1900 0 F and thus reducing the creep activation energy at this temperature from 202 kcal/mole to that of vacancy self-diffusion. It is noted that in general and especially at high temperatures the creep equation used to analyze creep data and creep activation energies must include the elastic modulus terms. Up to now, the neglect of these terms have by-in-large been justified. However, with the advent of very high temperature creep tests on the high temperature dispersion strengthened systems, the modulus terms must be taken into consideration. With respect to alloy designing for high temperature creep resistance, in addition to other considerations to obtain high temperature creep resistance, a high value of elastic modulus with a weak dependence on temperature at high temperatures is required

  8. Determination of young's modulus of PZT-influence of cantilever orientation

    NARCIS (Netherlands)

    Nazeer, H.; Woldering, L.A.; Abelmann, Leon; Elwenspoek, Michael Curt

    Calculation of the resonance frequency of cantilevers fabricated from an elastically anisotropic material requires the use of an effective Young’s modulus. In this paper a technique to determine the appropriate effective Young’s modulus for arbitrary cantilever geometries is introduced. This

  9. Estimation of the Young’s modulus of cellulose Iß by MM3 and quantum mechanics

    Science.gov (United States)

    Young’s modulus provides a measure of the resistance to deformation of an elastic material. In this study, modulus estimations for models of cellulose Iß relied on calculations performed with molecular mechanics (MM) and quantum mechanics (QM) programs. MM computations used the second generation emp...

  10. Percutaneous Dilational Tracheotomy in Solid-Organ Transplant Recipients.

    Science.gov (United States)

    Ozdemirkan, Aycan; Ersoy, Zeynep; Zeyneloglu, Pinar; Gedik, Ender; Pirat, Arash; Haberal, Mehmet

    2015-11-01

    Solid-organ transplant recipients may require percutaneous dilational tracheotomy because of prolonged mechanical ventilation or airway issues, but data regarding its safety and effectiveness in solid-organ transplant recipients are scarce. Here, we evaluated the safety, effectiveness, and benefits in terms of lung mechanics, complications, and patient comfort of percutaneous dilational tracheotomy in solid-organ transplant recipients. Medical records from 31 solid-organ transplant recipients (median age of 41.0 years [interquartile range, 18.0-53.0 y]) who underwent percutaneous dilational tracheotomy at our hospital between January 2010 and March 2015 were analyzed, including primary diagnosis, comorbidities, duration of orotracheal intubation and mechanical ventilation, length of intensive care unit and hospital stays, the time interval between transplant to percutaneous dilational tracheotomy, Acute Physiology and Chronic Health Evaluation II score, tracheotomy-related complications, and pulmonary compliance and ratio of partial pressure of arterial oxygen to fraction of inspired oxygen. The median Acute Physiology and Chronic Health Evaluation II score on admission was 24.0 (interquartile range, 18.0-29.0). The median interval from transplant to percutaneous dilational tracheotomy was 105.5 days (interquartile range, 13.0-2165.0 d). The only major complication noted was left-sided pneumothorax in 1 patient. There were no significant differences in ratio of partial pressure of arterial oxygen to fraction of inspired oxygen before and after procedure (170.0 [interquartile range, 102.2-302.0] vs 210.0 [interquartile range, 178.5-345.5]; P = .052). However, pulmonary compliance results preprocedure and postprocedure were significantly different (0.020 L/cm H2O [interquartile range, 0.015-0.030 L/cm H2O] vs 0.030 L/cm H2O [interquartile range, 0.020-0.041 L/cm H2O); P = .001]). Need for sedation significantly decreased after tracheotomy (from 17 patients [54.8%] to

  11. Aluminum oxide from trimethylaluminum and water by atomic layer deposition: The temperature dependence of residual stress, elastic modulus, hardness and adhesion

    International Nuclear Information System (INIS)

    Ylivaara, Oili M.E.; Liu, Xuwen; Kilpi, Lauri; Lyytinen, Jussi; Schneider, Dieter; Laitinen, Mikko; Julin, Jaakko; Ali, Saima; Sintonen, Sakari; Berdova, Maria; Haimi, Eero; Sajavaara, Timo; Ronkainen, Helena; Lipsanen, Harri

    2014-01-01

    Use of atomic layer deposition (ALD) in microelectromechanical systems (MEMS) has increased as ALD enables conformal growth on 3-dimensional structures at relatively low temperatures. For MEMS device design and fabrication, the understanding of stress and mechanical properties such as elastic modulus, hardness and adhesion of thin film is crucial. In this work a comprehensive characterization of the stress, elastic modulus, hardness and adhesion of ALD aluminum oxide (Al 2 O 3 ) films grown at 110–300 °C from trimethylaluminum and water is presented. Film stress was analyzed by wafer curvature measurements, elastic modulus by nanoindentation and surface-acoustic wave measurements, hardness by nanoindentation and adhesion by microscratch test and scanning nanowear. The films were also analyzed by ellipsometry, optical reflectometry, X-ray reflectivity and time-of-flight elastic recoil detection for refractive index, thickness, density and impurities. The ALD Al 2 O 3 films were under tensile stress in the scale of hundreds of MPa. The magnitude of the stress decreased strongly with increasing ALD temperature. The stress was stable during storage in air. Elastic modulus and hardness of ALD Al 2 O 3 saturated to a fairly constant value for growth at 150 to 300 °C, while ALD at 110 °C gave softer films with lower modulus. ALD Al 2 O 3 films adhered strongly on cleaned silicon with SiO x termination. - Highlights: • The residual stress of Al 2 O 3 was tensile and stable during the storage in air. • Elastic modulus of Al 2 O 3 saturated to at 170 GPa for films grown at 150 to 300 °C. • At 110 °C Al 2 O 3 films were softer with high residual hydrogen and lower density. • The Al 2 O 3 adhered strongly on the SiO x -terminated silicon

  12. A Prediction Method of Tensile Young's Modulus of Concrete at Early Age

    Directory of Open Access Journals (Sweden)

    Isamu Yoshitake

    2012-01-01

    Full Text Available Knowledge of the tensile Young's modulus of concrete at early ages is important for estimating the risk of cracking due to restrained shrinkage and thermal contraction. However, most often, the tensile modulus is considered equal to the compressive modulus and is estimated empirically based on the measurements of compressive strength. To evaluate the validity of this approach, the tensile Young's moduli of 6 concrete and mortar mixtures are measured using a direct tension test. The results show that the tensile moduli are approximately 1.0–1.3-times larger than the compressive moduli within the material's first week of age. To enable a direct estimation of the tensile modulus of concrete, a simple three-phase composite model is developed based on random distributions of coarse aggregate, mortar, and air void phases. The model predictions show good agreement with experimental measurements of tensile modulus at early age.

  13. Assessment of Characteristic Function Modulus of Vibroacoustic Signal Given a Limit State Parameter of Diagnosed Equipment

    Science.gov (United States)

    Kostyukov, V. N.; Naumenko, A. P.; Kudryavtseva, I. S.

    2018-01-01

    Improvement of distinguishing criteria, determining defects of machinery and mechanisms, by vibroacoustic signals is a recent problem for technical diagnostics. The work objective is assessment of instantaneous values by methods of statistical decision making theory and risk of regulatory values of characteristic function modulus. The modulus of the characteristic function is determined given a fixed parameter of the characteristic function. It is possible to determine the limits of the modulus, which correspond to different machine’s condition. The data of the modulus values are used as diagnostic features in the vibration diagnostics and monitoring systems. Using such static decision-making methods as: minimum number of wrong decisions, maximum likelihood, minimax, Neumann-Pearson characteristic function modulus limits are determined, separating conditions of a diagnosed object.

  14. E-modulus evolution and its relation to solids formation of pastes from commercial cements

    International Nuclear Information System (INIS)

    Maia, Lino; Azenha, Miguel; Geiker, Mette; Figueiras, Joaquim

    2012-01-01

    Models for early age E-modulus evolution of cement pastes are available in the literature, but their validation is limited. This paper provides correlated measurements of early age evolution of E-modulus and hydration of pastes from five commercial cements differing in limestone content. A recently developed methodology allowed continuous monitoring of E-modulus from the time of casting. The methodology is a variant of classic resonant frequency methods, which are based on determination of the first resonant frequency of a composite beam containing the material. The hydration kinetics — and thus the rate of formation of solids — was determined using chemical shrinkage measurements. For the cements studied similar relationships between E-modulus and chemical shrinkage were observed for comparable water-to-binder ratio. For commercial cements it is suggested to model the E-modulus evolution based on the amount of binder reacted, instead of the degree of hydration.

  15. Bisphosphonate treatment affects trabecular bone apparent modulus through micro-architecture rather than matrix properties

    DEFF Research Database (Denmark)

    Ding, Ming

    2004-01-01

    and trabecular architecture independently. Conventional histomorphometry and microdamage data were obtained from the second and third lumbar vertebrae of the same dogs [Bone 28 (2001) 524]. Bisphosphonate treatment resulted in an increased apparent Young's modulus, decreased bone turnover, increased calcified...... matrix density, and increased microdamage. We could not detect any change in the effective Young's modulus of the calcified matrix in the bisphosphonate treated groups. The observed increase in apparent Young's modulus was due to increased bone mass and altered trabecular architecture rather than changes...... in the calcified matrix modulus. We hypothesize that the expected increase in the Young's modulus of the calcified matrix due to the increased calcified matrix density was counteracted by the accumulation of microdamage. Udgivelsesdato: 2004 May...

  16. Proposal of Design Formulae for Equivalent Elasticity of Masonry Structures Made with Bricks of Low Modulus

    Directory of Open Access Journals (Sweden)

    Muhammad Ridwan

    2017-01-01

    Full Text Available Bricks of low elastic modulus are occasionally used in some developing countries, such as Indonesia and India. Most of the previous research efforts focused on masonry structures built with bricks of considerably high elastic modulus. The objective of this study is to quantify the equivalent elastic modulus of lower-stiffness masonry structures, when the mortar has a higher modulus of elasticity than the bricks, by employing finite element (FE simulations and adopting the homogenization technique. The reported numerical simulations adopted the two-dimensional representative volume elements (RVEs using quadrilateral elements with four nodes. The equivalent elastic moduli of composite elements with various bricks and mortar were quantified. The numerically estimated equivalent elastic moduli from the FE simulations were verified using previously established test data. Hence, a new simplified formula for the calculation of the equivalent modulus of elasticity of such masonry structures is proposed in the present study.

  17. Laboratory Performance Evaluation of High Modulus Asphalt Concrete Modified with Different Additives

    Directory of Open Access Journals (Sweden)

    Peng Li

    2017-01-01

    Full Text Available The objective of this study is to evaluate comprehensive performance of high modulus asphalt concrete (HMAC and propose common values for establishing evaluation system. Three gradations with different modifiers were conducted to study the high and low temperature performance, shearing behavior, and water stability. The laboratory tests for HMAC included static and dynamic modulus tests, rutting test, uniaxial penetration test, bending test, and immersion Marshall test. Dynamic modulus test results showed that modifier can improve the static modulus and the improvements were remarkable at higher temperature. Moreover, modulus of HMAC-20 was better than those of HMAC-16 and HMAC-25. The results of performance test indicated that HMAC has good performance to resist high temperature rutting, and the resistances of the HMAC-20 and HMAC-25 against rutting were better than that of HMAC-16. Then, the common values of dynamic stability were recommended. Furthermore, common values of HMAC performance were established based on pavement performance tests.

  18. Aeolian Sand Transport in the Planetary Context: Respective Roles of Aerodynamic and Bed-Dilatancy Thresholds

    Science.gov (United States)

    Marshall, J. R.; Borucki, J.; Bratton, C.

    1999-09-01

    The traditional view of aeolian sand transport generally estimates flux from the perspective of aerodynamic forces creating the airborne grain population, although it has been recognized that "reptation" causes a significant part of the total airborne flux; reptation involves both ballistic injection of grains into the air stream by the impact of saltating grains as well as the "nudging" of surface grains into a creeping motion. Whilst aerodynamic forces may initiate sand motion, it is proposed here that within a fully-matured grain cloud, flux is actually governed by two thresholds: an aerodynamic threshold, and a bed-dilatancy threshold. It is the latter which controls the reptation population, and its significance increases proportionally with transport energy. Because we only have experience with terrestrial sand transport, extrapolations of aeolian theory to Mars and Venus have adjusted only the aerodynamic factor, taking gravitational forces and atmospheric density as the prime variables in the aerodynamic equations, but neglecting reptation. The basis for our perspective on the importance of reptation and bed dilatancy is a set of experiments that were designed to simulate sand transport across the surface of a martian dune. Using a modified sporting crossbow in which a sand-impelling sabot replaced the bolt-firing mechanism, individual grains of sand were fired at loose sand targets with glancing angles typical of saltation impact; grains were projected at about 80 m/s to simulate velocities commensurate with those predicted for extreme martian aeolian conditions. The sabot impelling method permitted study of individual impacts without the masking effect of bed mobilization encountered in wind-tunnel studies. At these martian impact velocities, grains produced small craters formed by the ejection of several hundred grains from the bed. Unexpectedly, the craters were not elongated, despite glancing impact; the craters were very close to circular in planform

  19. The study of stiffness modulus values for AC-WC pavement

    Science.gov (United States)

    Lubis, AS; Muis, Z. A.; Iskandar, T. D.

    2018-02-01

    One of the parameters of the asphalt mixture in order for the strength and durability to be achieved as required is the stress-and-strain showing the stiffness of a material. Stiffness modulus is a very necessary factor that will affect the performance of asphalt pavements. If the stiffness modulus value decreases there will be a cause of aging asphalt pavement crack easily when receiving a heavy load. The high stiffness modulus asphalt concrete causes more stiff and resistant to bending. The stiffness modulus value of an asphalt mixture material can be obtained from the theoretical (indirect methods) and laboratory test results (direct methods). For the indirect methods used Brown & Brunton method, and Shell Bitumen method; while for the direct methods used the UMATTA tool. This study aims to determine stiffness modulus values for AC-WC pavement. The tests were conducted in laboratory that used 3 methods, i.e. Brown & Brunton Method, Shell Bitumen Method and Marshall Test as a substitute tool for the UMATTA tool. Hotmix asphalt made from type AC-WC with pen 60/70 using a mixture of optimum bitumen content was 5.84% with a standard temperature variation was 60°C and several variations of temperature that were 30, 40, 50, 70 and 80°C. The stiffness modulus value results obtained from Brown & Brunton Method, Shell Bitumen Method and Marshall Test which were 1374,93 Mpa, 235,45 Mpa dan 254,96 Mpa. The stiffness modulus value decreases with increasing temperature of the concrete asphalt. The stiffness modulus value from the Bitumen Shell method and the Marshall Test has a relatively similar value.The stiffness modulus value from the Brown & Brunton method is greater than the Bitumen Shell method and the Marshall Test, but can not measure the stiffness modulus value at temperature above 80°C.

  20. Data of methylome and transcriptome derived from human dilated cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Bong-Seok Jo

    2016-12-01

    Full Text Available Alterations in DNA methylation and gene expression have been implicated in the development of human dilated cardiomyopathy (DCM. Differentially methylated probes (DMPs and differentially expressed genes (DEGs were identified between the left ventricle (LV, a pathological locus for DCM and the right ventricle (RV, a proxy for normal hearts. The data in this DiB are for supporting our report entitled “Methylome analysis reveals alterations in DNA methylation in the regulatory regions of left ventricle development genes in human dilated cardiomyopathy” (Bong-Seok Jo, In-Uk Koh, Jae-Bum Bae, Ho-Yeong Yu, Eun-Seok Jeon, Hae-Young Lee, Jae-Joong Kim, Murim Choi, Sun Shim Choi, 2016 [1].

  1. Learning a Dilated Residual Network for SAR Image Despeckling

    Science.gov (United States)

    Zhang, Qiang; Yuan, Qiangqiang; Li, Jie; Yang, Zhen; Ma, Xiaoshuang

    2018-01-01

    In this paper, to break the limit of the traditional linear models for synthetic aperture radar (SAR) image despeckling, we propose a novel deep learning approach by learning a non-linear end-to-end mapping between the noisy and clean SAR images with a dilated residual network (SAR-DRN). SAR-DRN is based on dilated convolutions, which can both enlarge the receptive field and maintain the filter size and layer depth with a lightweight structure. In addition, skip connections and residual learning strategy are added to the despeckling model to maintain the image details and reduce the vanishing gradient problem. Compared with the traditional despeckling methods, the proposed method shows superior performance over the state-of-the-art methods on both quantitative and visual assessments, especially for strong speckle noise.

  2. Learning a Dilated Residual Network for SAR Image Despeckling

    Directory of Open Access Journals (Sweden)

    Qiang Zhang

    2018-01-01

    Full Text Available In this paper, to break the limit of the traditional linear models for synthetic aperture radar (SAR image despeckling, we propose a novel deep learning approach by learning a non-linear end-to-end mapping between the noisy and clean SAR images with a dilated residual network (SAR-DRN. SAR-DRN is based on dilated convolutions, which can both enlarge the receptive field and maintain the filter size and layer depth with a lightweight structure. In addition, skip connections and a residual learning strategy are added to the despeckling model to maintain the image details and reduce the vanishing gradient problem. Compared with the traditional despeckling methods, the proposed method shows a superior performance over the state-of-the-art methods in both quantitative and visual assessments, especially for strong speckle noise.

  3. Dilated Virchow–Robin spaces mimicking a brainstem arteriovenous malformation

    Directory of Open Access Journals (Sweden)

    Thomas J Buell

    2017-01-01

    Full Text Available Virchow–Robin spaces (VRS are ubiquitous and commonly observed as the resolution of magnetic resonance imaging (MRI continues to improve. The function of VRS and the etiology of their dilation is still a subject of research. Diagnosing dilated VRS (dVRS can be challenging because they may appear similar to other pathologies such as cystic neoplasms, infectious cysts, and even arteriovenous malformations (AVMs on certain MRI pulse sequences. We reported a unique case of brainstem dVRS mimicking an AVM. Furthermore, the extensive pontine involvement of our patient's lesion is rarely described in neurosurgical literature. Understanding the imaging characteristics of dVRS is critical to accurately diagnose these lesions and avoid unnecessary tests and procedures.

  4. Endoscopic Dilatation versus Oesophageal Stent in Benign Oesophageal Stricture

    Directory of Open Access Journals (Sweden)

    Hadyanto Caputra

    2016-09-01

    Full Text Available Aim: Oesophageal stricture is one of the causes of dysphagia. It is a condition in which the lumen of oesophagus is narrowed by fibrotic tissue in the oesophageal wall. It is usually caused by inflammation or any other cause that leads to necrotizing of tissue. It is mainly differentiated into benign or malignant. The aim of this article is to answer the clinical question on the effectiveness of oesophageal stenting compared to endoscopic dilatation in patient with benign oesophageal stricture due to ingestion of corrosive substances, who had undergone several endoscopic dilatations. Method: We conducted search of relevant articles using PubMed search engine to answer the clinical question. Keywords being used during the search process were: ("oesophageal stricture"[All Fields] OR "oesophageal stenosis"[All Fields] AND (("dilatation"[All Fields] AND ("stents"[MeSH Terms] OR "stents"[All Fields] OR "stent"[All Fields]. Results were further converged by adding specific filters, which were full text articles and clinical trial. Results: The chosen article was further appraised in order to identify its validity and eligibility to answer the clinical question. We chose to use CONSORT (statement to improve the quality of reporting of RCTs to facilitate the critical appraisal and interpretation of RCTs. Conclusion: Stenting was associated with greater dysphagia, co-medication and adverse events. No randomized controlled trials which compared biodegradable stents with other stents or with balloon dilatation was identified. Lack of adequately robust evidence for effectiveness and cost-effectiveness formed the rationale of this trial.

  5. Is there cosmological time dilation in gamma-ray bursts?

    Science.gov (United States)

    Band, David L.

    1994-01-01

    Norris et al. report that the temporal structure of faint gamma-ray bursts is longer than that of bright bursts, as expected for time dilation in the cosmological models of burst origin. I show that the observed trends can easily be produced by a burst luminosity function and thus may not result from cosmological effects. A cosmological signature may be present, but the tests Norris et al. present are not powerful enough to detect these signatures.

  6. Quantum Channels, Wavelets, Dilations and Representations of $O_n$

    OpenAIRE

    Kribs, David W.

    2003-01-01

    We show that the representations of the Cuntz C$^\\ast$-algebras $O_n$ which arise in wavelet analysis and dilation theory can be classified through a simple analysis of completely positive maps on finite-dimensional space. Based on this analysis, an application in quantum information theory is obtained; namely, a structure theorem for the fixed point set of a unital quantum channel. We also include some open problems motivated by this work.

  7. Mounier-Kuhn syndrome: a rare cause of bronchial dilation.

    Science.gov (United States)

    Celik, Burcin; Bilgin, Salih; Yuksel, Canan

    2011-01-01

    Mounier-Kuhn syndrome, or tracheobronchomegaly, is a rare clinical and radiologic condition characterized by marked tracheobronchial dilation and recurrent lower respiratory tract infections. Diagnosis is typically accomplished with the use of computed tomography and bronchoscopy, as well as pulmonary function testing. Patients may be asymptomatic; however, symptoms can range from minimal with preserved lung function to severe respiratory failure. Therapy, if any, is supportive but minimal. Surgery rarely has a place in the treatment of Mounier-Kuhn syndrome.Herein, we report the case of a 58-year-old man with chronic obstructive pulmonary disease who had a chronic cough, increased sputum production, and chest pain. Thoracic computed tomography showed tracheal dilation (diameter, 34 mm) and multiple diverticula in the posterior region of the trachea. Fiberoptic bronchoscopy revealed enlarged main bronchi, the dilated trachea, and prominent tracheal diverticula. Pulmonary function testing disclosed impaired respiratory function. Histopathologic examination of biopsy specimens from the bronchi and the tracheal wall supported the diagnosis of Mounier-Kuhn syndrome. The patient was released from the hospital and his condition was monitored for 2 years, during which time he developed no lower respiratory tract infections.Regardless of radiologic findings that suggest recurrent lower respiratory tract infection, we recommend that Mounier-Kuhn syndrome be considered in the differential diagnosis.

  8. Ethanol vapour induced dilated cardiomyopathy in chick embryos

    International Nuclear Information System (INIS)

    Kamran, K.; Khan, M.Y.; Minhas, L.A.

    2013-01-01

    Objective: To study the effects of ethanol vapour inhalation on the heart chambers of chick embryo. Methods: The case-control study was conducted at the College of Physicians and Surgeons Pakistan regional centre in Islamabad from January to October 2007. Both experimental and control groups were divided into three sub-groups each, based on the day of the sacrifice. Each group was dissected on day 7, day 10 and day 22 or hatching whichever was earlier. The experimental sub-groups sacrificed on day 7, day 10 and on hatching, were exposed to ethanol vapours till day 6, 9 and 9 of incubation respectively. The diameter of all 4 chambers was measured in experimental hearts and compared with age-matched controls. SPSS 10 was used for statistical analysis. Results: Ethanol vapour exposure caused widening of all heart chambers in the experimental chick embryos sacrificed on day 7 and day 10 compared to the controls. The chambers of newly hatched chick hearts showed dilatation in all the chambers except the left ventricle. Conclusion: Ethanol vapour exposure during development affects the heart, resulting in the widening of all heart chambers. The exposure is as dangerous as drinking alcohol. Alcohol vapour exposure during development leads to progressive dilatation in different heart chambers, producing dilated cardiomyopathy. (author)

  9. Massively dilated right atrium masquerading as a mediastinal tumor

    Directory of Open Access Journals (Sweden)

    Thomas Schroeter

    2011-04-01

    Full Text Available Severe tricuspid valve insufficiency causes right atrial dilatation, venous congestion, and reduced atrial contractility, and may eventually lead to right heart failure. We report a case of a patient with severe tricuspid valve insufficiency, right heart failure, and a massively dilated right atrium. The enormously dilated atrium compressed the right lung, resulting in a radiographic appearance of a mediastinal tumor. Tricuspid valve repair and reduction of the right atrium was performed. Follow up examination revealed improvement of liver function, reduced peripheral edema and improved New York Heart Association (NYHA class. The reduction of the atrial size and repair of the tricuspid valve resulted in a restoration of the conduit and reservoir function of the right atrium. Given the chronicity of the disease process and the long-standing atrial fibrillation, there is no impact of this operation on right atrial contraction. In combination with the reconstruction of the tricuspid valve, the reduction atrioplasty will reduce the risk of thrombembolic events and preserve the right ventricular function.

  10. [Aneurysmal dilatation of pulmonary artery and its branches on mitral stenosis: a case report].

    Science.gov (United States)

    Yaméogo, N V; Ndiaye, M B; Diao, M; Cabral-Ciss, E C; Sarr, M; Ba, S A

    2013-02-01

    Pulmonary arteries aneurysms are rare and the rarely described bilateral aneurysms. A 45-year-old patient carrier of mitral stenosis was admitted for dyspnoea class III of the NYHA, chest pain and a not infectious cough. The clinical examination found semiology of mitral stenosis, tricuspid incapacity and pulmonary arterial hypertension. The electrocardiogram showed atrial fibrillation and right ventricle hypertrophy. Chest X-ray found a cardiomegaly, an aspect of double outline of the inferior right bow, a prominent aspect of the left average bow reminding an aneurysm of the left pulmonary artery. The echocardiography Doppler found a pure tight mitral stenosis (mitral surface=0.6 cm(2)), a dilation of the trunk of the pulmonary artery (diameter=74 mm) and of its branches (diameter of the right pulmonary artery=28 mm, diameter of the left pulmonary artery=36 mm) seat of a spontaneous contrast. The left atrium and right cardiac cavities were also dilated. There was an important tricuspid incapacity with a major pulmonary hypertension (systolic pulmonary arterial=109 mmHg). The thoracic angioscan showed a pseudoaneurysm of the trunk of pulmonary artery and its branches to their distal parts. Under diuretic, anticoagulating and analgesic treatment the clinical signs improved however the spontaneous contrast persisted. The patient was rejected by the surgery for exceeded clinical board. She is at present followed in our service for 5 months. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  11. Dilated odontoma: A report of two cases from a radiological perspective

    Science.gov (United States)

    Jayachandran, S.; Kayal, L.; Sharma, Aatman; Priyanka, Khobre

    2016-01-01

    Dilated odontoma is the most extreme form of dens invaginatus. The lesion appears as a roughly spherical mass that does not resemble a tooth but in a way appears tooth - like on radiographs due to somewhat similar radiodensity. The lesion is mostly spherical in appearance and hence the term “dilated.” Occasionally, we come across cases of simultaneous pathologies. Here, we report two cases of a dilated odontoma one of which is associated with dentigerous cyst and in other case dilated odontoma pushing the maxillary sinus superiorly. Histologically, the mass was composed of dentinal tubules. These morphological and histological features are compatible with those of a dilated odontoma. PMID:27041914

  12. Dilated odontoma: A report of two cases from a radiological perspective

    Directory of Open Access Journals (Sweden)

    S Jayachandran

    2016-01-01

    Full Text Available Dilated odontoma is the most extreme form of dens invaginatus. The lesion appears as a roughly spherical mass that does not resemble a tooth but in a way appears tooth - like on radiographs due to somewhat similar radiodensity. The lesion is mostly spherical in appearance and hence the term “dilated.” Occasionally, we come across cases of simultaneous pathologies. Here, we report two cases of a dilated odontoma one of which is associated with dentigerous cyst and in other case dilated odontoma pushing the maxillary sinus superiorly. Histologically, the mass was composed of dentinal tubules. These morphological and histological features are compatible with those of a dilated odontoma.

  13. Hybrid cutting balloon dilatation for treatment of cor triatriatum sinister in a cat.

    Science.gov (United States)

    Stern, Joshua A; Tou, Sandra P; Barker, Piers C A; Hill, Kevin D; Lodge, Andrew J; Mathews, Kyle G; Keene, Bruce W

    2013-09-01

    A hybrid surgical approach and balloon dilatation were performed successfully in a cat with cor triatriatum sinister and clinical signs of congestive heart failure. Left lateral thoracotomy was used to access the heart and cutting balloon followed by standard balloon dilatation were utilized to dilate the perforation in the anomalous left atrial membrane. Clinical signs resolved completely after dilation of the anomalous left atrial membrane. Based upon the outcome of this case, balloon dilatation appears to be a viable treatment option for cats affected with cor triatriatum sinister. Published by Elsevier B.V.

  14. Young's modulus determination of low-k porous films by wide-band DCC/LD LSAW

    Science.gov (United States)

    Maosen, Bai; Xing, Fu; Dorantes, Dante; Baoyin, Jin; Xiaotang, Hu

    2011-10-01

    Low-k interconnection is one of the key concepts in the development of high-speed ultra-large-scale integrated (ULSI) circuits. To determine the Young's modulus of ultra thin, low hardness and fragile low-k porous films more accurately, a wideband differential confocal configured laser detected and laser-generated surface acoustic wave (DCC/LD LSAW) detection system is developed. Based on the light deflection sensitivity detection principle, with a novel differential confocal configuration, this DCC/LD LSAW system extends the traditional laser generated surface acoustic wave (LSAW) detection system's working frequency band, making the detected SAW signals less affected by the hard substrate and providing more information about the thin porous low-k film under test. Thus it has the ability to obtain more accurate measurement results. Its detecting principle is explained and a sample of porous silica film on Si (100) is tested. A procedure of fitting an experimental SAW dispersion curve with theoretical dispersion curves was carried out in the high frequency band newly achieved by the DCC/LD LSAW system. A comparison of the measurement results of the DCC/LD LSAW with those from the traditional LSAW shows that this newly developed DCC/LD LSAW can dramatically improve the Young's modulus measuring accuracy of such porous low-k films.

  15. Young's modulus determination of low-k porous films by wide-band DCC/LD LSAW

    International Nuclear Information System (INIS)

    Bai Maosen; Fu Xing; Dorantes Dante; Jin Baoyin; Hu Xiaotang

    2011-01-01

    Low-k interconnection is one of the key concepts in the development of high-speed ultra-large-scale integrated (ULSI) circuits. To determine the Young's modulus of ultra thin, low hardness and fragile low-k porous films more accurately, a wideband differential confocal configured laser detected and laser-generated surface acoustic wave (DCC/LD LSAW) detection system is developed. Based on the light deflection sensitivity detection principle, with a novel differential confocal configuration, this DCC/LD LSAW system extends the traditional laser generated surface acoustic wave (LSAW) detection system's working frequency band, making the detected SAW signals less affected by the hard substrate and providing more information about the thin porous low-k film under test. Thus it has the ability to obtain more accurate measurement results. Its detecting principle is explained and a sample of porous silica film on Si (100) is tested. A procedure of fitting an experimental SAW dispersion curve with theoretical dispersion curves was carried out in the high frequency band newly achieved by the DCC/LD LSAW system. A comparison of the measurement results of the DCC/LD LSAW with those from the traditional LSAW shows that this newly developed DCC/LD LSAW can dramatically improve the Young's modulus measuring accuracy of such porous low-k films. (semiconductor materials)

  16. The effect of frequency on Young's modulus and seismic wave attenuation

    International Nuclear Information System (INIS)

    Price, R.H.

    1994-07-01

    Laboratory experiments were performed to measure the effect of frequency, water-saturation, and strain amplitude on Young's modulus and seismic wave attenuation on rock cores recovered on or near the site of a potential nuclear waste repository at Yucca Mountain, Nevada. The purpose of this investigation is to perform the measurements using four techniques: cyclic loading, waveform inversion, resonant bar, and ultrasonic velocity. The measurements ranged in frequency between 10 -2 and 10 6 Hz. For the dry specimens Young's modulus and attenuation were independent of frequency; that is, all four techniques yielded nearly the same values for modulus and attenuation. For saturated specimens, a frequency dependence for both Young's modulus and attenuation was observed. In general, saturation reduced Young's modulus and increased seismic wave attenuation. The effect of strain amplitude on Young's modulus and attenuation was measured using the cyclic loading technique at a frequency of 10 -1 Hz. The effect of strain amplitude in all cases was small. For some rocks, such as the potential repository horizon of the Topopah Spring Member tuff (TSw2), the effect of strain amplitude on both attenuation and modulus was minimal

  17. Proposal for a revised definition of dilated cardiomyopathy, hypokinetic non-dilated cardiomyopathy, and its implications for clinical practice

    DEFF Research Database (Denmark)

    Pinto, Yigal M; Elliott, Perry M; Arbustini, Eloisa

    2016-01-01

    In this paper the Working Group on Myocardial and Pericardial Disease proposes a revised definition of dilated cardiomyopathy (DCM) in an attempt to bridge the gap between our recent understanding of the disease spectrum and its clinical presentation in relatives, which is key for early diagnosis...... and the institution of potential preventative measures. We also provide practical hints to identify subsets of the DCM syndrome where aetiology directed management has great clinical relevance....

  18. An analytic model of the shear modulus at all densities and temperatures

    OpenAIRE

    Burakovsky, L.; Greeff, C. W.; Preston, D. L.

    2002-01-01

    An analytic model of the shear modulus applicable at temperatures up to melt and at all densities is presented. It is based in part on a relation between the melting temperature and the shear modulus at melt. Experimental data on argon are shown to agree with this relation to within 1%. The model of the shear modulus involves seven parameters, all of which can be determined from zero-pressure experimental data. We obtain the values of these parameters for 11 elemental solids. Both the experim...

  19. Spontaneous magnetic contribution to a bulk modulus of ferromagnetic metals (with gadolinium taken as an example)

    International Nuclear Information System (INIS)

    Bodryakov, V.Yu.; Povzner, A.A.; Zelyukova, O.G.

    1999-01-01

    A thermodynamic approach to the description of magnetic contribution into ferromagnetic metals elastic modulus variations is developed on the basis of the Landau second type phase transitions theory. It is shown that the magnetostriction variation of not considered previously Landau's thermodynamic parameters α and β is an essential reason for all-round compression elastic modulus varying with magnetization. In addition, to detect the magnetic contribution into the elastic modulus from experimental data an expression is derived for its temperature dependence in a paramagnetic developed and experimental data is made for a ferromagnetic phase of gadolinium [ru

  20. E-modulus evolution and its relation to solids formation of pastes from commercial cements

    DEFF Research Database (Denmark)

    Maia, Lino; Azenha, Miguel; Geiker, Mette

    2012-01-01

    developed methodology allowed continuous monitoring of E-modulus from the time of casting. The methodology is a variant of classic resonant frequency methods, which are based on determination of the first resonant frequency of a composite beam containing the material. The hydration kinetics — and thus...... the rate of formation of solids — was determined using chemical shrinkage measurements. For the cements studied similar relationships between E-modulus and chemical shrinkage were observed for comparable water-to-binder ratio. For commercial cements it is suggested to model the E-modulus evolution based...

  1. Reliable measurement of elastic modulus of cells by nanoindentation in an atomic force microscope

    KAUST Repository

    Zhou, Zhoulong

    2012-04-01

    The elastic modulus of an oral cancer cell line UM1 is investigated by nanoindentation in an atomic force microscope with a flat-ended tip. The commonly used Hertzian method gives apparent elastic modulus which increases with the loading rate, indicating strong effects of viscoelasticity. On the contrary, a rate-jump method developed for viscoelastic materials gives elastic modulus values which are independent of the rate-jump magnitude. The results show that the rate-jump method can be used as a standard protocol for measuring elastic stiffness of living cells, since the measured values are intrinsic properties of the cells. © 2011 Elsevier Ltd.

  2. Effect of steam oxidation on strength, elastic modulus, and strain at fracture of graphite 2020

    International Nuclear Information System (INIS)

    Velasquez, C.; Hightower, G.; Burnette, R.

    1977-12-01

    Stackpole Carbon's graphite grade 2020, a candidate material for support posts in GA HTGRs, was oxidized in steam-helium mixtures to 25 wt % burnoff. The effects of the oxidation on ultimate strength, elastic modulus, and strain at fracture are reported. A large number of nonoxidized and oxidized tensile specimens were tested to failure. Average losses of 6.7 wt % in strength and 7.4 wt % in elastic modulus at 1% burnoff were obtained. No significant change in strain at fracture was observed for burnoffs up to 5%. The elastic modulus and ultimate tensile strength of the oxidized samples correlated with bulk density

  3. Highly porous, low elastic modulus 316L stainless steel scaffold prepared by selective laser melting.

    Science.gov (United States)

    Čapek, Jaroslav; Machová, Markéta; Fousová, Michaela; Kubásek, Jiří; Vojtěch, Dalibor; Fojt, Jaroslav; Jablonská, Eva; Lipov, Jan; Ruml, Tomáš

    2016-12-01

    Recently, porous metallic materials have been extensively studied as candidates for use in the fabrication of scaffolds and augmentations to repair trabecular bone defects, e.g. in surroundings of joint replacements. Fabricating these complex structures by using common approaches (e.g., casting and machining) is very challenging. Therefore, rapid prototyping techniques, such as selective laser melting (SLM), have been investigated for these applications. In this study, we characterized a highly porous (87 vol.%) 316L stainless steel scaffold prepared by SLM. 316L steel was chosen because it presents a biomaterial still widely used for fabrication of joint replacements and, from the practical point of view, use of the same material for fabrication of an augmentation and a joint replacement is beneficial for corrosion prevention. The results are compared to the reported properties of two representative nonporous 316L stainless steels prepared either by SLM or casting and subsequent hot forging. The microstructural and mechanical properties and the surface chemical composition and interaction with the cells were investigated. The studied material exhibited mechanical properties that were similar to those of trabecular bone (compressive modulus of elasticity ~0.15GPa, compressive yield strength ~3MPa) and cytocompatibility after one day that was similar to that of wrought 316L stainless steel, which is a commonly used biomaterial. Based on the obtained results, SLM is a suitable method for the fabrication of porous 316L stainless steel scaffolds with highly porous structures. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Young's modulus and degree of conversion of different combination of light-cure dental resins.

    Science.gov (United States)

    Emami, N; Söderholm, Kj

    2009-10-01

    To evaluate Young's modulus and degree of conversion of several combinations of bisGMA, UEDMA, TEGDMA light-cure dental resin. Young's modulus and DC% were studied for 21 different resin combinations of bisGMA, TEGDMA and UEDMA. Small universal testing machine and photo-calorimetry were used for the tests. The results were evaluated using ANOVA and Duncan's multiple range tests and regular t-test. Young's modulus varied between 2.37±0.2 GPa (100% TEGDMA) and 4.15±0.2 GPa (100% bisGMA). By adding TEGDMA to bisGMA or UEDMA, the Young's modulus decreased significantly (pphysical properties of the mixtures.

  5. Wind Diffusivity Current, METOP ASCAT, 0.25 degrees, Global, Near Real Time, Modulus

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA CoastWatch distributes near real time Ekman current (in zonal, meridional, and modulus sets) and Ekman upwelling data. This data begins with wind velocity...

  6. Longitudinal ultrasonic velocity as a predictor of Young`s modulus in porous materials

    Energy Technology Data Exchange (ETDEWEB)

    Panakkal, J.P. [Bhabha Atomic Research Centre, Thane (India). Advanced Fuel Fabrication Facility

    1997-12-01

    The relationship between Young`s modulus and longitudinal ultrasonic velocity is discussed by using examples from various types of ceramics: nuclear, structural, powder metal, clay and super-conducting. A semi-empirical model is suggested based on the existing theories (elasticity, powder metallurgy, scattering, and connected grain) of ultrasound wave propagation in porous materials. The linear relationship between Young`s modulus and ultrasonic velocity over a change of Young`s modulus by 50 percent is demonstrated in porous materials and generalized to suggest the use of ultrasonic velocity as a predictor of Young`s modulus in porous materials. The values extrapolated from this relationship for nonporous materials are in good agreement with the experimental values. The behavior is also compared with that predicted from the various models.

  7. Wind Stress, QuikSCAT SeaWinds, 0.25 degrees, Global, Science Quality, Modulus

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA CoastWatch distributes science quality wind stress data in zonal, meridional, modulus, and wind stress curl sets. This data begins with wind velocity...

  8. Failure Modes of a Unidirectional Ultra-High-Modulus Carbon-Fiber/Carbon-Matrix Composite

    National Research Council Canada - National Science Library

    Zaldivar, R

    1998-01-01

    The objective of this study was to observe the effects of various microstructural features on the in situ, room-temperature tensile fracture behavior of an ultra-high-modulus, unidirectional carbon/carbon (C/C...

  9. Magnetic contribution to bulk modulus of elasticity of ferromagnetic metal (with gadolinium as an example)

    International Nuclear Information System (INIS)

    Bodryakov, V.Yu.; Povzner, A.A.

    2000-01-01

    Magnetic contribution into the bulk modulus of elasticity of ferromagnetic metal within the external magnetic fields depending on temperature was studied in terms of diamagnetic approach to the theory of phase transformations. The effect of magnetostriction on the Landau thermodynamic coefficients was determined to bring about that contribution. The value of the magnetic constituent of the bulk modulus of elasticity within B = 2.5 T magnetic field was calculated on the basis of data on ultrasonic measurements. The exact comparison with the experiment was conducted using data on the dependence of the bulk modulus of elasticity of gadolinium ferromagnetic phase on the external magnetic field as an example. Dissimilar nature of variation of the elastic modulus of bulk elasticity at transition of rare-earth magnetics and of 3d-metal ferromagnetic alloys to the ferromagnetic state was observed [ru

  10. Short cellulosic fiber/starch acetate composites — micromechanical modeling of Young’s modulus

    DEFF Research Database (Denmark)

    Madsen, Bo; Joffe, Roberts; Peltola, Heidi

    2011-01-01

    This study is presented to predict the Young’s modulus of injection-molded short cellulosic fiber/plasticized starch acetate composites with variable fiber and plasticizer content. A modified rule of mixtures model is applied where the effect of porosity is included, and where the fiber weight...... (density and Young’s modulus). The measured Young’s modulus of the composites varies in the range 1.1—8.3 GPa, and this is well predicted by the model calculations. A property diagram is presented to be used for the tailor-making of composites with Young’s modulus in the range 0.2—10 GPa....

  11. Mechanical properties of concrete with SAP. Part II: Modulus of elasticity

    DEFF Research Database (Denmark)

    Hasholt, Marianne Tange; Jespersen, Morten H. Seneka; Jensen, Ole Mejlhede

    2010-01-01

    of air voids. Second, SAP addition may at the same time lead to increased compressive strength (as shown in [5]) and reduced E-modulus. A prediction based solely on compressive strength therefore overrates the modulus of elasticity, so the empirical models are unsafe to use for concrete with SAP......, and air with volume fractions of the three phases as well as elastic properties of paste and aggregates as input parameters. Addition of SAP changes the E-modulus, because it both has an influence on properties of the cement paste and on the volume of air voids. Here, the E-modulus is an example...... of a mechanical property, and the same methodology can probably be applied to other mechanical properties. It is often assumed that a range of mechanical properties of concrete can be derived if the compressive strength is known. The link between the compressive strength and other mechanical properties is often...

  12. Design values of resilient modulus of stabilized and non-stabilized base.

    Science.gov (United States)

    2010-10-01

    The primary objective of this research study is to determine design value ranges for typical base materials, as allowed by LADOTD specifications, through laboratory tests with respect to resilient modulus and other parameters used by pavement design ...

  13. Experimental Study of Estimating the Subgrade Reaction Modulus on Jointed Rock Foundations

    Science.gov (United States)

    Lee, Jaehwan; Jeong, Sangseom

    2016-06-01

    The subgrade reaction modulus for rock foundations under axial loading is investigated by model footing tests. This study focuses on quantifying a new subgrade reaction modulus by considering rock discontinuities. A series of model-scale footing tests are performed to investigate the effects of the unconfined compressive strength, discontinuity spacing and inclination of the rock joint. Based on the experimental results, it is observed that the subgrade reaction modulus of the rock with discontinuities decreases by up to approximately 60 % of intact rock. In addition, it is found that the modulus of subgrade reaction is proportional to the discontinuity spacing, and it decreases gradually within the range of 0°-30° and tends to increase within the range of 30°-90°.

  14. Wind Stress, METOP ASCAT, 0.25 degrees, Global, Near Real Time, Modulus

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA CoastWatch distributes near real time wind stress data in zonal, meridional, modulus, and wind stress curl sets. This data begins with wind velocity...

  15. The dimensional stability and elastic modulus of cemented simulant Winfrith reactor (SGHWR) sludge

    International Nuclear Information System (INIS)

    Holland, T.R.; Lee, D.J.

    1985-12-01

    Dimensional changes and elastic modulus have been monitored on cemented simulant sludge stored in various environments. Specimens prepared using a blended cement show no serious detrimental effects during sealed storage, underwater storage or freeze/thaw cycling. (author)

  16. Resilient modulus for unbound granular materials and subgrade soils in Egypt

    Directory of Open Access Journals (Sweden)

    Mousa Rabah

    2017-01-01

    Full Text Available Mechanistic Empirical (ME pavement design methods started to gain attention especially the last couple of years in Egypt and the Middle East. One of the challenges facing the spread of these methods in Egypt is lack of advanced properties of local soil and asphalt, which are needed as input data in ME design. Resilient modulus (Mr for example is an important engineering property that expresses the elastic behavior of soil/unbound granular materials (UGMs under cyclic traffic loading for ME design. In order to overcome the scarcity of the resilient modulus data for soil/UGMs in Egypt, a comprehensive laboratory testing program was conducted to measure resilient modulus of typical UGMs and subgrade soils typically used in pavement construction in Egypt. The factors that affect the resilient modulus of soil/UGMs were reviewed, studied and discussed. Finally, the prediction accuracy of the most well-known Mr Prediction models for the locally investigated materials was investigated.

  17. The bicuspid aortic valve and its relation to aortic dilation

    Directory of Open Access Journals (Sweden)

    Shi-Min Yuan

    2010-01-01

    Full Text Available BACKGROUND: A bicuspid aortic valve (BAV is a common congenital heart disease, which affects 1-2% of the population. However, the relationship between BAVs and aortic dilation has not been sufficiently elucidated. METHODS: A total of 241 BAV patients who were referred to this hospital for cardiac surgey over a 4.75-year period were included in this study. In addition to the clinical characteristics of the included patients, the morphological features of the aortic valve and aorta, the length of the left main coronary artery, and the laboratory findings (the coagulation and hematological parameters as well as the total cholesterol concentration were determined and compared with those of the tricuspid aortic valve (TAV patients. RESULTS: The BAV patients were younger than the TAV patients for a valve surgery in the last 3 months of the study period. The BAV patients were predominantly male. Most of the BAVs that were surgically treated were stenotic, regurgitant, or combined, and only 19 (7.88% were normally functioning valves. According to echocardiography or operative records, 148 (78.31% were type A, 31 (16.40% were type B, and 10 (5.29% were type C. The left main coronary artery was much shorter in the BAV patients than it was in the TAV patients. There was no significant difference between BAV and TAV patients in the total cholesterol concentrations; whereas differences were noted between patients receiving lipid-lowering therapy and those not receiving lipid-lowering therapy. The dimensions of the aortic root, sinotubular junction, and ascending aorta were beyond normal limits, while they were significantly smaller in the BAV patients than in the TAV patients. They were also much smaller in patients receiving statin therapy than those not receiving statin therapy in both groups. Moreover, the aortic dilation in the BAV group was found to be significantly associated with patient age. CONCLUSIONS: The BAV patients developed aortic wall and

  18. Young modulus and internal friction of a fiber-reinforced composite

    International Nuclear Information System (INIS)

    Ledbetter, H.M.; Lei, M.; Austin, M.W.

    1986-01-01

    By a kilohertz-frequency resonance method we determined the Young modulus and internal friction of a uniaxially fiber-reinforced composite. The composite comprised glass fibers in an epoxy-resin matrix. We studied three fiber contents: 0, 41, and 49 vol %. The Young modulus fit a linear rule of mixture. The internal friction fit a classical free-damped-oscillator model where one assumes a linear rule of mixture for three quantities: mass, force constant, and mechanical-resistance constant

  19. A two-crown finite element technique for the determination of tearing modulus

    International Nuclear Information System (INIS)

    Suo, X.Z.; Combescure, A.

    1989-01-01

    The importance of approach to the subject of crack instability for the design of structures containing cracks has increased considerably over the last few years. The tearing modulus theory recently enunciated by Paris and co-workers has emerged as one of the leading criterions for stable crack growth and for instability, and the estimation of T termed Tearing modulus in the theory has since been extensively investigated theoretically as well as experimentally. Analytical methods exist for calculating the tearing modulus of various crack configurations in simple-shaped structures under certain loading conditions. However, for arbitrary structures under general loading, more sophisticated calculation techniques are required. Extending the virtual crack extension method introduced independently by Hellen and Parks, a new numerical approach for calculating the tearing modulus is presented hereafter and put in a form suitable for the instability analysis of structures containing one single crack or several interacting cracks. As it is well-known that the calculation of the energy release rate in elasticity by the virtual crack extension method is related to a stiffness derivative to which only a small region around the crack tip has a contribution, the technique described in the paper shows that it would be reasonable to evaluate the tearing modulus, or rather, the second derivative of potential energy with respect to the crack length, by means of two stiffness derivative calculations in two crowns around the crack tip. In particular, when one crown is strictly included in another one, computation is largely curtailed at this point with some saving of computer time, but a very accurate value of tearing modulus is obtained. As an interesting consequence, an another expression of the tearing modulus is carried out. In Section 4: the classical tearing modulus is proved to be precisely equivalent to a line integral which is independent of integration path. Numerical example

  20. Young's modulus of a copper-stabilized niobium-titanium superconductive wire

    International Nuclear Information System (INIS)

    Ledbetter, H.M.; Moulder, J.C.; Austin, M.W.

    1980-01-01

    Young's modulus was determined for a 0.6-mm-dia niobium-titanium superconductive wire. Two methods were used: continuous-wave-resonance and laser-pulse-excitation. Young's moduli were also determined for the components - copper and Nb-Ti - in both wire and bulk forms. Some mechanical-deformation effects on Young's modulus were also measured. From the component' elastic moduli, that of the composite was predicted accurately by a simple rule-of-mixtures relationship

  1. Magnetic resonance imaging of dilated cardiomyopathy; MRT bei dilatativen Kardiomyopathien

    Energy Technology Data Exchange (ETDEWEB)

    D' Anastasi, M. [Klinikum der Ludwig-Maximilians-Universitaet Muenchen, Campus Grosshadern, Institut fuer Klinische Radiologie, Muenchen (Germany); Greif, M. [Klinikum der Ludwig-Maximilians-Universitaet Muenchen, Campus Grosshadern, Medizinische Klinik und Poliklinik I, Muenchen (Germany); Reiser, M.F.; Theisen, D. [Klinikum der Ludwig-Maximilians-Universitaet Muenchen, Campus Grosshadern, Institut fuer Klinische Radiologie, Muenchen (Germany); Deutsches Zentrum fuer Herzkreislaufforschung (DZHK), Muenchen (Germany)

    2013-01-15

    Dilated cardiomyopathy (DCM) is the most common type of cardiomyopathy with a prevalence of 1 out of 2,500 in adults. Due to mild clinical symptoms in the early phase of the disease, the true prevalence is probably even much higher. Patients present with variable clinical symptoms ranging from mild systolic impairment of left ventricular function to congestive heart failure. Even sudden cardiac death may be the first clinical symptom of DCM. The severity of the disease is defined by the degree of impairment of global left ventricular function. Arrhythmias, such as ventricular or supraventricular tachycardia, atrioventricular (AV) block, ventricular extrasystole and atrial fibrillation are common cardiac manifestations of DCM. Magnetic resonance imaging (MRI) plays an important role in the exact quantification of functional impairment of both ventricles and in the evaluation of regional wall motion abnormalities. With its excellent ability for the assessment of myocardial structure, it is becoming increasingly more important for risk stratification and therapy guidance. (orig.) [German] Die dilatative Kardiomyopathie (DCM) ist die haeufigste Form der Kardiomyopathie mit einer Praevalenz von 1/2500 Erwachsenen. Aufgrund der zunaechst milden klinischen Symptomatik ist jedoch von einer relativ hohen Dunkelziffer auszugehen. Die klinische Praesentation ist variabel, die Schwere der Erkrankung wird vom Ausmass der systolischen Funktionseinschraenkung bestimmt. Herzrhythmusstoerungen, wie ventrikulaere oder supraventrikulaere Tachykardien, AV-Blockierungen, ventrikulaere Extrasystolen und Vorhofflimmern sind moegliche klinische Manifestationen. Bei manchen Patienten ist der ploetzliche Herztod die erste klinische Manifestation der Erkrankung. Die kardiale MRT spielt eine bedeutende Rolle fuer die Beurteilung des Ausmasses der ventrikulaeren Dilatation, Dysfunktion und fuer die Beurteilung regionaler Wandbewegungsstoerungen. Darueber hinaus kann sie zur Anwendung kommen

  2. Time Dilation and Homogeneous, Soft-Spectrum GRBs

    Science.gov (United States)

    Norris, J. P.; Bonnell, J. T.; Nemiroff, R. J.; Scargle, J. D.; Pendleton, G. N.; Kouveliotou, C.; Pizzichini, G.

    1996-12-01

    Recently, BATSE gamma-ray bursts selected for soft average spectra have been shown to follow more nearly a -3/2 power law in their number-intensity relation, indicative of a spatially homogeneous population, unlike the whole BATSE burst sample which deviates significantly from a -3/2 signature. The softer bursts might therefore be closer, and the reported time dilation as a function of peak flux in the whole burst sample (Bonnell et al., ApJ submitted) might be expected to be different for soft bursts. We have investigated this possibility with a sample of 500 long bursts (T_90 > 2 s) from the BATSE 3B catalog, defining soft bursts ( ~ 20% of total) using the three hardness ratios derived from fluences in BATSE's four energy channels (25--55, 55--110, 110--320, > 320 keV). The relative time-dilation factors (TDFs) were calculated using a brightness-independent algorithm for duration. The expected effect is observed: The average log[duration] of soft bursts is significantly lower (factor of ~ 2) than that for harder bursts, or for the whole set, to much dimmer peak fluxes -- consistent with unity TDF (compared to bright bursts in the whole sample) down to peak flux of ~ 1.0 photon cm(-2) s(-1) . Using a Kolmogorov-Smirnov test, we find that T_90 and T_50 duration distributions of soft and hard bursts above this peak flux value are different, with a confidence level > 99%. This result is qualitatively consistent with a GRB luminosity function implied by the apparent homogeneity of the bright-to-intermediate peak-flux soft bursts. However, dimmer soft bursts are time-dilated relative to bright bursts in the whole sample, suggesting that spectral redshift compounds the definition of the soft burst class.

  3. Intragastric balloon for morbid obesity causing chronic gastric dilatation

    International Nuclear Information System (INIS)

    Pretolesi, F.; Derchi, L.E.; Redaelli, G.; Papagni, L.

    2001-01-01

    We describe the radiographic findings observed in a morbidly obese and diabetic patient with an intragastric air-filled balloon introduced as a therapeutic measure to reduce food intake. The balloon was associated with chronic gastric dilatation and had to be removed 3 months after insertion. However, together with diet and behavioural therapy, it proved effective in reducing body weight and ameliorating glycaemic control. Although rarely used, intragastric balloons for the treatment of morbid obesity are still encountered in radiological practice. Radiologists must be able to recognize them and to understand their complications. (orig.)

  4. Genotype-specific pathogenic effects in human dilated cardiomyopathy.

    Science.gov (United States)

    Bollen, Ilse A E; Schuldt, Maike; Harakalova, Magdalena; Vink, Aryan; Asselbergs, Folkert W; Pinto, Jose R; Krüger, Martina; Kuster, Diederik W D; van der Velden, Jolanda

    2017-07-15

    Mutations in genes encoding cardiac troponin I (TNNI3) and cardiac troponin T (TNNT2) caused altered troponin protein stoichiometry in patients with dilated cardiomyopathy. TNNI3 p.98trunc resulted in haploinsufficiency, increased Ca 2+ -sensitivity and reduced length-dependent activation. TNNT2 p.K217del caused increased passive tension. A mutation in the gene encoding Lamin A/C (LMNA p.R331Q ) led to reduced maximal force development through secondary disease remodelling in patients suffering from dilated cardiomyopathy. Our study shows that different gene mutations induce dilated cardiomyopathy via diverse cellular pathways. Dilated cardiomyopathy (DCM) can be caused by mutations in sarcomeric and non-sarcomeric genes. In this study we defined the pathogenic effects of three DCM-causing mutations: the sarcomeric mutations in genes encoding cardiac troponin I (TNNI3 p.98truncation ) and cardiac troponin T (TNNT2 p.K217deletion ; also known as the p.K210del) and the non-sarcomeric gene mutation encoding lamin A/C (LMNA p.R331Q ). We assessed sarcomeric protein expression and phosphorylation and contractile behaviour in single membrane-permeabilized cardiomyocytes in human left ventricular heart tissue. Exchange with recombinant troponin complex was used to establish the direct pathogenic effects of the mutations in TNNI3 and TNNT2. The TNNI3 p.98trunc and TNNT2 p.K217del mutation showed reduced expression of troponin I to 39% and 51%, troponin T to 64% and 53%, and troponin C to 73% and 97% of controls, respectively, and altered stoichiometry between the three cardiac troponin subunits. The TNNI3 p.98trunc showed pure haploinsufficiency, increased Ca 2+ -sensitivity and impaired length-dependent activation. The TNNT2 p.K217del mutation showed a significant increase in passive tension that was not due to changes in titin isoform composition or phosphorylation. Exchange with wild-type troponin complex corrected troponin protein levels to 83% of controls in the TNNI3

  5. Genotype‐specific pathogenic effects in human dilated cardiomyopathy

    Science.gov (United States)

    Schuldt, Maike; Harakalova, Magdalena; Vink, Aryan; Asselbergs, Folkert W.; Pinto, Jose R.; Krüger, Martina; Kuster, Diederik W. D.; van der Velden, Jolanda

    2017-01-01

    Key points Mutations in genes encoding cardiac troponin I (TNNI3) and cardiac troponin T (TNNT2) caused altered troponin protein stoichiometry in patients with dilated cardiomyopathy. TNNI3p.98trunc resulted in haploinsufficiency, increased Ca2+‐sensitivity and reduced length‐dependent activation. TNNT2p.K217del caused increased passive tension.A mutation in the gene encoding Lamin A/C (LMNA p.R331Q) led to reduced maximal force development through secondary disease remodelling in patients suffering from dilated cardiomyopathy.Our study shows that different gene mutations induce dilated cardiomyopathy via diverse cellular pathways. Abstract Dilated cardiomyopathy (DCM) can be caused by mutations in sarcomeric and non‐sarcomeric genes. In this study we defined the pathogenic effects of three DCM‐causing mutations: the sarcomeric mutations in genes encoding cardiac troponin I (TNNI3p.98truncation) and cardiac troponin T (TNNT2p.K217deletion; also known as the p.K210del) and the non‐sarcomeric gene mutation encoding lamin A/C (LMNAp.R331Q). We assessed sarcomeric protein expression and phosphorylation and contractile behaviour in single membrane‐permeabilized cardiomyocytes in human left ventricular heart tissue. Exchange with recombinant troponin complex was used to establish the direct pathogenic effects of the mutations in TNNI3 and TNNT2. The TNNI3p.98trunc and TNNT2p.K217del mutation showed reduced expression of troponin I to 39% and 51%, troponin T to 64% and 53%, and troponin C to 73% and 97% of controls, respectively, and altered stoichiometry between the three cardiac troponin subunits. The TNNI3p.98trunc showed pure haploinsufficiency, increased Ca2+‐sensitivity and impaired length‐dependent activation. The TNNT2p.K217del mutation showed a significant increase in passive tension that was not due to changes in titin isoform composition or phosphorylation. Exchange with wild‐type troponin complex corrected troponin protein levels to 83% of

  6. Achalasia with massive oesophageal dilation causing tracheomalacia and asthma symptoms

    Directory of Open Access Journals (Sweden)

    Ana Gomez-Larrauri

    Full Text Available Achalasia is an uncommon oesophageal motor disorder characterized by failure of relaxation of the lower oesophageal sphincter and muscle hypertrophy, resulting in a loss of peristalsis and a dilated oesophagus. Gastrointestinal symptoms are invariably present in all cases of achalasia observed in adults. We report a case of a 34 year-old female patient with long standing history of asthma-like symptoms, labelled as uncontrolled and steroid resistant asthma with no gastrointestinal manifestations. Thoracic CT scan revealed a massive oesophagus due to achalasia, which caused severe tracheomalacia as a result of tracheal compression. Her symptoms regressed completely after a laparoscopic Heller myotomy surgery intervention.

  7. Intragastric balloon for morbid obesity causing chronic gastric dilatation

    Energy Technology Data Exchange (ETDEWEB)

    Pretolesi, F.; Derchi, L.E. [Dept. of Radiology, University of Genoa (Italy); Redaelli, G.; Papagni, L. [IRCCS, Ist. Auxologico Italiano, Milan (Italy)

    2001-04-01

    We describe the radiographic findings observed in a morbidly obese and diabetic patient with an intragastric air-filled balloon introduced as a therapeutic measure to reduce food intake. The balloon was associated with chronic gastric dilatation and had to be removed 3 months after insertion. However, together with diet and behavioural therapy, it proved effective in reducing body weight and ameliorating glycaemic control. Although rarely used, intragastric balloons for the treatment of morbid obesity are still encountered in radiological practice. Radiologists must be able to recognize them and to understand their complications. (orig.)

  8. Elastic Modulus of Fe72.5Ga27.5 Magnetostrictive Alloy

    International Nuclear Information System (INIS)

    Xiao-Xi, Zhu; Jing-Hua, Liu; Cheng-Bao, Jiang

    2010-01-01

    The elastic modulus of Fe 72.5 Ga 27.5 magnetostrictive alloy is determined by testing ac impedance resonance frequency and first-principle calculations. The observed elastic modulus is 90.2 GPa for a directionally solidified sample and 103.4 GPa for a water-quenched sample tested in a dc magnetic field of 32.7 mT without compressive pre-stress. The bulk modulus by first-principles calculation is 179.3 GPa which is basically consistent with the experimental result. The elastic modulus first increases and then decreases with increasing dc magnetic field, attributed to magnetostriction occurrence in the Fe 72.5 Ga 27.5 alloy. The elastic modulus increases with increasing compressive pre-stress, resulting from the initial magnetic states change under the applied compressive pre-stress. The elastic modulus increases match well with the improved magnetostriction after quenching. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  9. Developing the elastic modulus measurement of asphalt concrete using the compressive strength test

    Science.gov (United States)

    Setiawan, Arief; Suparma, Latif Budi; Mulyono, Agus Taufik

    2017-11-01

    Elastic modulus is a fundamental property of an asphalt mixture. An analytical method of the elastic modulus is needed to determine the thickness of flexible pavement. It has a role as one of the input values on a stress-strain analysis in the finite element method. The aim of this study was to develop the measurement of the elastic modulus by using compressive strength testing. This research used a set of specimen mold tool and Delta Dimensi software to record strain changes occurring in the proving ring of compression machine and the specimens. The elastic modulus of the five types of aggregate gradation and 2 types of asphalt were measured at optimum asphalt content. Asphalt Cement 60/70 and Elastomer Modified Asphalt (EMA) were used as a binder. Manufacturing success indicators of the specimens used void-in-the-mix (VIM) 3-5 % criteria. The success rate of the specimen manufacturing was more than 76%. Thus, the procedure and the compressive strength test equipment could be used for the measurement of the elastic modulus. The aggregate gradation and asphalt types significantly affected the elastic modulus of the asphalt concrete.

  10. Fracture Toughness and Elastic Modulus of Epoxy-Based Nanocomposites with Dopamine-Modified Nano-Fillers

    Directory of Open Access Journals (Sweden)

    Kwang Liang Koh

    2017-07-01

    Full Text Available This paper examines the effect of surface treatment and filler shape factor on the fracture toughness and elastic modulus of epoxy-based nanocomposite. Two forms of nanofillers, polydopamine-coated montmorillonite clay (D-clay and polydopamine-coated carbon nanofibres (D-CNF were investigated. It was found that Young’s modulus increases with increasing D-clay and D-CNF loading. However, the fracture toughness decreases with increased D-clay loading but increases with increased D-CNF loading. Explanations have been provided with the aid of fractographic analysis using electron microscope observations of the crack-filler interactions. Fractographic analysis suggests that although polydopamine provides a strong adhesion between the fillers and the matrix, leading to enhanced elastic stiffness, the enhancement prohibits energy release via secondary cracking, resulting in a decrease in fracture toughness. In contrast, 1D fibre is effective in increasing the energy dissipation during fracture through crack deflection, fibre debonding, fibre break, and pull-out.

  11. Fracture Toughness and Elastic Modulus of Epoxy-Based Nanocomposites with Dopamine-Modified Nano-Fillers.

    Science.gov (United States)

    Koh, Kwang Liang; Ji, Xianbai; Dasari, Aravind; Lu, Xuehong; Lau, Soo Khim; Chen, Zhong

    2017-07-10

    This paper examines the effect of surface treatment and filler shape factor on the fracture toughness and elastic modulus of epoxy-based nanocomposite. Two forms of nanofillers, polydopamine-coated montmorillonite clay (D-clay) and polydopamine-coated carbon nanofibres (D-CNF) were investigated. It was found that Young's modulus increases with increasing D-clay and D-CNF loading. However, the fracture toughness decreases with increased D-clay loading but increases with increased D-CNF loading. Explanations have been provided with the aid of fractographic analysis using electron microscope observations of the crack-filler interactions. Fractographic analysis suggests that although polydopamine provides a strong adhesion between the fillers and the matrix, leading to enhanced elastic stiffness, the enhancement prohibits energy release via secondary cracking, resulting in a decrease in fracture toughness. In contrast, 1D fibre is effective in increasing the energy dissipation during fracture through crack deflection, fibre debonding, fibre break, and pull-out.

  12. Dilatation of aortic grafts over time: what to expect and when to be concerned

    DEFF Research Database (Denmark)

    Schroeder, Torben V; Eldrup, Nikolaj; Just, Sven

    2009-01-01

    insertion of a woven polyester or expanded polytetrafluoroethylene (ePTFE) graft. Patients were followed with computed tomography and ultrasonography for up to 5 years in order to assess the frequency and magnitude of postoperative dilatation. Graft dilatation was documented in patients with polyester...... grafts at 12 months. Thereafter and up to 60 months, polyester grafts did not dilate further. After 5 years, polyester prostheses had dilated by 25% and ePTFE by 12.5%, as determined by computed tomography imaging. These observations suggest that dilatation of prosthetic grafts is more frequent...... with knitted polyester grafts compared with ePTFE. Dilatation occurs within the first year after implantation and can be, in part, explained by a discrepancy between the initial nominal graft diameter and its diameter after clamp release, probably due to an in vivo adaptation of the textile structure...

  13. Cognitive effort and pupil dilation in controlled and automatic processes.

    Science.gov (United States)

    Querino, Emanuel; Dos Santos, Lafaiete; Ginani, Giuliano; Nicolau, Eduardo; Miranda, Débora; Romano-Silva, Marco; Malloy-Diniz, Leandro

    2015-01-01

    The Five Digits Test (FDT) is a Stroop paradigm test that aims to evaluate executive functions. It is composed of four parts, two of which are related to automatic and two of which are related to controlled processes. It is known that pupillary diameter increases as the task's cognitive demand increases. In the present study, we evaluated whether the pupillary diameter could distinguish cognitive effort between automated and controlled cognitive processing during the FDT as the task progressed. As a control task, we used a simple reading paradigm with a similar visual aspect as the FDT. We then divided each of the four parts into two blocks in order to evaluate the differences between the first and second half of the task. Results indicated that, compared to a control task, the FDT required higher cognitive effort for each consecutive part. Moreover, the first half of every part of the FDT induced dilation more than the second. The differences in pupil dilation during the first half of the four FDT parts were statistically significant between the parts 2 and 4 (p=0.023), and between the parts 3 and 4 (p=0.006). These results provide further evidence that cognitive effort and pupil diameter can distinguish controlled from automatic processes.

  14. Laryngotracheal Stenosis: Risk Factors for Tracheostomy Dependence and Dilation Interval

    Science.gov (United States)

    Gadkaree, Shekhar K; Pandian, Vinciya; Best, Simon; Motz, Kevin M; Allen, Clint; Kim, Young; Akst, Lee; Hillel, Alexander T

    2017-02-01

    Objective Laryngotracheal stenosis (LTS) is a fibrotic process that narrows the upper airway and has a significant impact on breathing and phonation. Iatrogenic injury from endotracheal and/or tracheostomy tubes is the most common etiology. This study investigates differences in LTS etiologies as they relate to tracheostomy dependence and dilation interval. Study Design Case series with chart review. Setting Single-center tertiary care facility. Subjects and Methods Review of adult patients with LTS was performed between 2004 and 2015. The association of patient demographics, comorbidities, disease etiology, and treatment modalities with patient outcomes was assessed. Multiple logistic regression analysis and Kaplan-Meier analysis were performed to determine factors associated with tracheostomy dependence and time to second procedure, respectively. Results A total of 262 patients met inclusion criteria. Iatrogenic patients presented with greater stenosis ( P = .023), greater length of stenosis ( P = .004), and stenosis farther from the vocal folds ( P tracheostomy dependence. Nonsmokers, patients without tracheostomy, and idiopathic LTS patients had a significantly longer time to second dilation procedure. Conclusion Iatrogenic LTS presents with a greater disease burden and higher risk of tracheostomy dependence when compared with other etiologies of LTS. Comorbid conditions promoting microvascular injury-including smoking, COPD, and diabetes-were prevalent in the iatrogenic cohort. Changes in hospital practice patterns to promote earlier tracheostomy in high-risk patients could reduce the incidence of LTS.

  15. Percutaneous dilatational tracheostomy for ICU patients with severe brain injury

    Directory of Open Access Journals (Sweden)

    Guo Dongyuan

    2014-12-01

    Full Text Available 【Abstract】Objective: To sum up our experience in percutaneous dilatational tracheostomy (PDT in ICU patient with severe brain injury. Methods: Between November 2011 and April 2014, PDTs were performed on 32 severe brain injury patients in ICU by a team of physicians and intensivists. The success rate, effi cacy, safety, and complications including stomal infection and bleeding, paratracheal insertion, pneumothorax, pneumomediastinum, tracheal laceration, as well as clinically significant tracheal stenosis were carefully monitored and recorded respectively. Results: The operations took 4-15 minutes (mean 9.1 minutes±4.2 minutes. Totally 4 cases suffered from complications in the operations: 3 cases of stomal bleeding, and 1 case of intratracheal bloody secretion, but none required intervention. Paratracheal insertion, pneumothorax, pneumomediastinum, tracheal laceration, or clinically signifi cant tracheal stenosis were not found in PDT patients. There was no procedure-related death occurring during or after PDT. Conclusion: Our study demonstrats that PDT is a safe, highly effective, and minimally invasive procedure. The appropriate sedation and airway management perioperatively help to reduce complication rates. PDT should be performed or supervised by a team of physicians with extensive experience in this procedure, and also an intensivist with experience in diffi cult airway management. Key words: Brain injuries; Percutaneous dilatational tracheostomy; ICU

  16. Dilated cardiomyopathy with Graves disease in a young child

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    Yu Jung Choi

    2016-06-01

    Full Text Available Graves disease (GD can lead to complications such as cardiac arrhythmia and heart failure. Although dilated cardiomyopathy (DCMP has been occasionally reported in adults with GD, it is rare in children. We present the case of a 32-month-old boy with DCMP due to GD. He presented with irritability, vomiting, and diarrhea. He also had a history of weight loss over the past few months. On physical examination, he had tachycardia without fever, a mild diffuse goiter, and hepatomegaly. The chest radiograph showed cardiomegaly with pulmonary edema, while the echocardiography revealed a dilated left ventricle with an ejection fraction (EF of 28%. The thyroid function test (TFT showed elevated serum T3 and decreased thyroid stimulating hormone (TSH levels. The TSH receptor autoantibody titer was elevated. He was diagnosed with DCMP with GD; treatment with methylprednisolone, diuretics, inotropics, and methimazole was initiated. The EF improved after the TFT normalized. At follow-up several months later, although the TFT results again showed evidence of hyperthyroidism, his EF had not deteriorated. His cardiac function continues to remain normal 1.5 months after treatment was started, although he still has elevated T3 and high TSH receptor antibody titer levels due to poor compliance with drug therapy. To summarize, we report a young child with GD-induced DCMP who recovered completely with medical therapy and, even though the hyperthyroidism recurred several months later, there was no relapse of the DCMP.

  17. Pneumatic dilation and botulinum toxin: when and why?

    Science.gov (United States)

    Bozzi, Rosamaria; Di Martino, Vincenzo; Inzirillo, Antonio; D'Avenia, Eugenio; Inzirillo, Maurizio; Cattaneo, Fabio; Cattaneo, Domenico

    2013-01-01

    Pneumatic dilation and botulinum toxin:when and why? The endoscopic treatment options of achalasia include botulinum toxin (BT) injection and pneumatic dilation (PD) of the lower esophageal sphincter (LES). BT can reduce the LES pressure by blocking the release of acetylcoline from presynaptic cholinergic nerve terminals in the myenteric plexus. Although the procedure is safe and good initial response is reported, there is a wide variability in the duration of the response and the effect tends to decrease over time. BT is usually recommended for elderly patients or patients with comorbid illnesses, who are poor candidates for more invasive procedures. PD aims at tearing the muscle fibers of the LES and is considered the most effective nonsurgical treatment for achalasia. Technical details of the procedure vary in different institutions and in many clinical settings the choice between PD or minimally invasive surgical myotomy depends upon local expertise in the procedures. Further endoscopic treatment options such as submucosal esophageal myotomy or self-expanding metallic stents are being studied.

  18. Antenatal renal pelvic dilatation; the long-term outlook

    Energy Technology Data Exchange (ETDEWEB)

    Duncan, K.A. [Royal Aberdeen Children' s Hospital and Aberdeen Maternity Hospital, Foresterhill, Aberdeen (United Kingdom)]. E-mail: k.duncan@nhs.net

    2007-02-15

    Aim: The purpose of this study was twofold: first to provide data for more accurate counselling of parents with regard to prognosis, and second, to ensure that by following a policy of selective micturating cystourethography (MCUG), significant pathology is not missed, in particular vesicoureteric reflux (VUR). (MCUG is only undertaken if the renal pelvic diameter (RPD) is {>=} 10 mm or if there is calyceal or ureteric dilatation.) Material and methods: Data were collected prospectively over a 6-year period. Pre and postnatal imaging findings were collected for all infants in whom a RPD of {>=} 5 mm was identified at any gestational age. The imaging records of all patients were reviewed in 2005 for evidence of pathology detected after re-presentation with symptoms. The age range at review varied from 2-8 years. Results: Complete data were available in 527 infants. The risk of significant pathology was related to the degree of antenatal renal pelvic dilatation varying from 6% for a RPD of 5 mm at 20 weeks gestation to 38% at 10mm. At 28-33 weeks gestation the risk varied from 5% at 5 mm to 15% at 10 mm. Subsequent imaging record review revealed only one patient with grade II VUR in the study population not picked up by our selective MCUG policy. Conclusion: The present study provides prognostic information that can be given to parents both antenatally and postnatally, and reassurance that a selective MCUG policy is appropriate.

  19. Multiple Genetic Associations with Irish Wolfhound Dilated Cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Siobhan Simpson

    2016-01-01

    Full Text Available Cardiac disease is a leading cause of morbidity and mortality in dogs and humans, with dilated cardiomyopathy being a large contributor to this. The Irish Wolfhound (IWH is one of the most commonly affected breeds and one of the few breeds with genetic loci associated with the disease. Mutations in more than 50 genes are associated with human dilated cardiomyopathy (DCM, yet very few are also associated with canine DCM. Furthermore, none of the identified canine loci explain many cases of the disease and previous work has indicated that genotypes at multiple loci may act together to influence disease development. In this study, loci previously associated with DCM in IWH were tested for associations in a new cohort both individually and in combination. We have identified loci significantly associated with the disease individually, but no genotypes individually or in pairs conferred a significantly greater risk of developing DCM than the population risk. However combining three loci together did result in the identification of a genotype which conferred a greater risk of disease than the overall population risk. This study suggests multiple rather than individual genetic factors, cooperating to influence DCM risk in IWH.

  20. Management of esophageal perforation after pneumatic dilation for achalasia.

    Science.gov (United States)

    Hunt, D R; Wills, V L; Weis, B; Jorgensen, J O; DeCarle, D J; Coo, I J

    2000-01-01

    Current management of esophageal perforation after pneumatic dilation for achalasia is thoracotomy and repair with myotomy. This study aims to assess the outcome of patients managed by laparotomy, and the role of laparoscopic repair. The study was carried out by means of retrospective case review and prospective follow-up with a symptom questionnaire. Results were compared with results in patients undergoing elective Heller myotomy. Over a 20-year period, 445 dilations for achalasia were performed in 371 patients. There were 10 esophageal perforations. Nine patients were referred for surgery and were successfully managed with a transabdominal repair. Laparoscopic repair was attempted in four patients but was successful in only one because of the perforation site. After a mean follow-up of 5.4 years, grade 1 or 2 Visick scores were recorded in all patients. Residual symptoms of dysphagia occurred in 67% in the emergency group and 88% in the elective group. There was an increased incidence of heart-burn compared to elective myotomy. Early operation after perforation provides good results for treatment of achalasia. Mild dysphagia persists and there is an increasing sensation of heartburn. The site of perforation is typically posterolateral, which makes laparoscopic repair difficult.

  1. Posterior chamber volume does not change significantly during dilation.

    Science.gov (United States)

    Dorairaj, S; Liebmann, J M; Tello, C; Barocas, V H; Ritch, R

    2009-11-01

    To determine whether the volume of the posterior chamber changes during pupillary dilation. Eyes with anatomically narrow angles underwent ultrasound biomicroscopy of the posterior chamber and pupillary margin under dark- and light-room conditions to assess changes in posterior chamber anatomy and volume. All examinations were stored as real-time video. A frame-by-frame analysis was performed using a macro written for the ImageJ image-processing software. Thirteen eyes were assessed. The mean patient age was 63.0 (SD 10.0) years, and the mean refractive error was 1.1 (1.9) dioptres. The horizontal mean pupillary diameter was 2.3 (0.6) mm and 3.5 (0.5) mm under light- and dark-room conditions, respectively (pchamber volumes were unchanged under light and dark conditions (3.76 (1.09) vs 3.63 (0.78) mm(3), p = 0.22, paired t test). Volumes were greater under light conditions in eight eyes and under dark conditions in five eyes. The volume of the posterior chamber does not change significantly during dilation.

  2. [Expansion dilatation balloons for cervical ripening in obstetric practice].

    Science.gov (United States)

    Ducarme, G; Grange, J; Vital, M

    2016-02-01

    During recent decades, mechanical devices have been substituted by pharmacological methods. Their place in the therapeutic arsenal remains important with a renewed obstetrical interest for these devices. Due to a lack of data they are still not recommended as first-line. This review thus attempted to examine the use of expansion dilatation balloons (Foley catheter and double-balloons) to analyze their effectiveness in case of native uterus and previous cesarean section. Twenty-seven clinical trials had compared balloons catheter and prostaglandins in patients without a history of uterine scar. The risk of cesarean section did not differ. Mechanical methods seemed to be more effective in achieving delivery within 24hours, with fewer episodes of excessive uterine contractions, but they necessitated more oxytocin during labor. Ten clinical trials analyzed dilatation balloons in patients with previous cesarean section. More than 70% women had favorable cervical ripening (Bishop score>6), and vaginal delivery was reported between 35 and 70% of patients. The risk of uterine rupture was low between 0.64 and 0.72%, with neither increased risk of severe neonatal and maternal morbidity nor increased risk of infectious morbidity. Mechanical methods are effective and safe for third trimester cervical ripening, mainly in women with previous cesarean section. Potential advantages may include wide availability and reduction of some of the side effects. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  3. External nasal dilators: definition, background, and current uses

    Directory of Open Access Journals (Sweden)

    Dinardi RR

    2014-11-01

    Full Text Available Ricardo Reis Dinardi, Cláudia Ribeiro de Andrade, Cássio da Cunha Ibiapina Department of Pediatrics, Pediatric Pulmonology Unit, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil Abstract: Our goal was to revise the literature about external nasal dilators (ENDs as to their definition, history, and current uses. We reviewed journals in the PubMed and MEDLINE databases. The current uses hereby presented and discussed are physical exercise, nasal congestion and sleep, snoring, pregnancy, cancer, and healthy individuals. Numerous studies have shown that ENDs increase the cross-sectional area of the nasal valve, reducing nasal resistance and transnasal inspiratory pressure and stabilizing the lateral nasal vestibule, avoiding its collapse during final inspiration. These effects also facilitate breathing and are beneficial to patients with nasal obstruction. Furthermore, END use is simple, noninvasive, painless, affordable, and bears minimum risk to the user. Most studies have limited sample size and are mainly focused on physical exercise. In conclusion, ENDs seem useful, so further studies involving potential effects on the performance of physical tests and improvements in sleep quality are necessary, especially in children and teenagers. Keywords: external nasal dilator, nasal valve, nasal congestion, nasal resistance

  4. Endoscopic Dilation of Pharyngoesophageal Strictures: There Are More Dimensions than a Diameter

    Directory of Open Access Journals (Sweden)

    Diana Martins

    2018-02-01

    Full Text Available Background/Aims: Dysphagia due to benign pharyngoesophageal strictures (PES often requires repeated dilations; however, a uniform definition for the therapeutic efficacy of this technique has not been yet established. We aimed to assess the overall efficacy of endoscopic dilation of pharyngoesophageal anastomotic or post-radiotherapy (post-RT strictures. Methods: The data of 48 patients with post-RT (n = 29 or anastomotic PES (n = 19 submitted to endoscopic dilation during a 3-year period were retrospectively assessed. The Kochman criteria were used to determine refractoriness and recurrence. Patients were asked to answer a questionnaire determining prospectively the dilation program efficacy as (a dysphagia improvement, (b dysphagia resolution, (c need for further dilations, or (d percutaneous endoscopic gastrostomy (PEG during the previous 6 months. Need for additional therapy was considered an inefficacy criterion. Results: The median number of dilations per patient was 4 (total of 296 dilations with a median follow-up of 29 months. The mean predilation dysphagia Mellow-Pinkas score was 3 and the initial stenosis diameter was 7 mm. Fifteen and 29% of patients presented with the Kochman criteria for refractory and recurrent strictures, respectively. Moreover, 96 and 60% showed dysphagia improvement and resolution, respectively. Seventy-five-percent did not require dilations during 6 months, and 89% did not require PEG. From the patients’ perspective, overall efficacy was achieved in 58% of cases. Nine additional therapies were required. Number of dilations (OR 0.7, stricture diameter (OR 2.2, and nonrecurrence criteria (OR 14.2 appeared as significant predictors of overall efficacy, whereas refractory stenosis criteria did not. Conclusions: Endoscopic dilation seems to be effective for patients with dysphagia after RT or surgery, especially when assessed as patient perception of improvement. Narrow strictures, recurrent ones, and strictures

  5. Sinus Balloon Dilation as Treatment for Acute Sphenoid Sinusitis with Impaired Vision for a Child

    Directory of Open Access Journals (Sweden)

    Yin Zhao

    2016-01-01

    Full Text Available This paper is about sinus balloon dilatation in treatment of acute left sphenoid sinusitis with left impaired vision in a child. Balloon catheter dilatation (BCD of the sinus ostia is a new technique. It has been shown to be a minimally invasive technique to manage chronic sinusitis. However, this method is rarely used in the treatment of acute sinusitis. So far, we know of no reported cases of sinus balloon dilatation in treatment of this case, especially for children.

  6. Tissue modulus calculated from beam theory is biased by bone size and geometry: implications for the use of three-point bending tests to determine bone tissue modulus.

    Science.gov (United States)

    van Lenthe, G Harry; Voide, Romain; Boyd, Steven K; Müller, Ralph

    2008-10-01

    Current practice to determine bone tissue modulus of murine cortical bone is to estimate it from three-point bending tests, using Euler-Bernoulli beam theory. However, murine femora are not perfect beams; hence, results can be inaccurate. Our aim was to assess the accuracy of beam theory, which we tested for two commonly used inbred strains of mice, C57BL/6 (B6) and C3H/He (C3H). We measured the three-dimensional structure of male and female B6 and C3H femora (N=20/group) by means of micro-computed tomography. For each femur five micro-finite element (micro-FE) models were created that simulated three-point bending tests with varying distances between the supports. Tissue modulus was calculated from beam theory using micro-FE results. The accuracy of beam theory was assessed by comparing the beam theory-derived moduli with the modulus as used in the micro-FE analyses. An additional set of fresh-frozen femora (10 B6 and 12 C3H) was biomechanically tested and subjected to the same micro-FE analyses. These combined experimental-computational analyses enabled an unbiased assessment of specimen-specific tissue modulus. We found that by using beam theory, tissue modulus was underestimated for all femora. Femoral geometry and size had strong effects on beam theory-derived tissue moduli. Owing to their relatively thin cortex, underestimation was markedly higher for B6 than for C3H. Underestimation was dependent on support width in a strain-specific manner. From our combined experimental-computational approach we calculated tissue moduli of 12.0+/-1.3 GPa and 13.4+/-2.1 GPa for B6 and C3H, respectively. We conclude that tissue moduli in murine femora are strongly underestimated when calculated from beam theory. Using image-based micro-FE analyses we could precisely quantify this underestimation. We showed that previously reported murine inbred strain-specific differences in tissue modulus are largely an effect of geometric differences, not accounted for by beam theory. We

  7. Resilient modulus prediction of soft low-plasticity Piedmont residual soil using dynamic cone penetrometer

    Directory of Open Access Journals (Sweden)

    S. Hamed Mousavi

    2018-04-01

    Full Text Available Dynamic cone penetrometer (DCP has been used for decades to estimate the shear strength and stiffness properties of the subgrade soils. There are several empirical correlations in the literature to predict the resilient modulus values at only a specific stress state from DCP data, corresponding to the predefined thicknesses of pavement layers (a 50 mm asphalt wearing course, a 100 mm asphalt binder course and a 200 mm aggregate base course. In this study, field-measured DCP data were utilized to estimate the resilient modulus of low-plasticity subgrade Piedmont residual soil. Piedmont residual soils are in-place weathered soils from igneous and metamorphic rocks, as opposed to transported or compacted soils. Hence the existing empirical correlations might not be applicable for these soils. An experimental program was conducted incorporating field DCP and laboratory resilient modulus tests on “undisturbed” soil specimens. The DCP tests were carried out at various locations in four test sections to evaluate subgrade stiffness variation laterally and with depth. Laboratory resilient modulus test results were analyzed in the context of the mechanistic-empirical pavement design guide (MEPDG recommended universal constitutive model. A new approach for predicting the resilient modulus from DCP by estimating MEPDG constitutive model coefficients (k1, k2 and k3 was developed through statistical analyses. The new model is capable of not only taking into account the in situ soil condition on the basis of field measurements, but also representing the resilient modulus at any stress state which addresses a limitation with existing empirical DCP models and its applicability for a specific case. Validation of the model is demonstrated by using data that were not used for model development, as well as data reported in the literature. Keywords: Dynamic cone penetrometer (DCP, Resilient modulus, Mechanistic-empirical pavement design guide (MEPDG, Residual

  8. Measurement of the Young’s modulus using micro-cantilevered beam actuated by electrostatic force

    Science.gov (United States)

    Wang, Zhichong; Zhang, Qichang; Wang, Chen

    2018-02-01

    Determining the Young’s modulus accurately is important in micro-electro-mechanical systems (MEMS) design. Generally, the Young’s modulus of a micro-component is measured by the resonance method, of which the actuation is electrostatic force. However, this method does not take the effect of the electrostatic force on the resonant frequency into consideration. Thus, the test error becomes more obvious as the DC voltage increases. In this paper, an improved resonance method, determining the Young’s modulus of a micro-cantilever beam, is proposed, which takes the nonlinearity of the electrostatic force into consideration. This method has three obvious advantages: only one simple micro-cantilevered beam sample is needed; it is unnecessary to find the initial thickness of the gas film between the beam and the substrate; the accuracy of the measurement result of the Young’s modulus is improved. In order to obtain the resonant frequency of a cantilevered beam actuated by a DC voltage, the dynamic equations of the micro-cantilevered beam in multi-field coupled situations are established, and the effect of the electrostatic force on the resonant frequency of the micro-beam is investigated. Results show that, the Young’s modulus can be found by measuring the resonant frequency and DC voltage. The dynamics performances of the micro-structure are influenced by the nonlinearity of the electrostatic force, and the electrostatic effect should be observed especially when the beam becomes smaller, through general studies. Finally, the experimental principle of measuring the Young’s modulus is designed and conducted to verify these theories. The Young’s modulus of brass is measured exactly.

  9. The therapy of esophageal stricture caused by erosive through balloon dilation

    International Nuclear Information System (INIS)

    Li Yi; Zeng Xianqiang; Wang Rongqin; Ding Xiaolin; You Guoqing; Shao Hede; Zhang Xinyuan

    2004-01-01

    Objective: To evaluate the therapy of esophageal stricture caused by erosive burn of esophagus through balloon dilation. Methods: 9 patients of esophageal stricture caused by erosive burn of esophagus have been treated by balloon dilation. Results: 9 patients have been dilated 26 times altogether 7 of them can eat normally. 2 patients' symptoms were improved. Six months to two years after operation, the symptoms were not reoccurred. All of them have no serious complications. Conclusion: Balloon dilation is one of the effective and safe therapy of esophageal stricture caused by erosive burn. (authors)

  10. Dilatant normal faulting in jointed cohesive rocks: insights from physical modeling

    Science.gov (United States)

    Kettermann, Michael; von Hagke, Christoph; Urai, Janos

    2016-04-01

    Dilatant faults often form in rocks containing pre-existing joints, but the effects of joints on fault segment linkage and fracture connectivity is not well understood. Studying evolution of dilatancy and influence of fractures on fault development provides insights on geometry of fault zones in brittle rocks and eventually allows for predicting their subsurface appearance. We assess the evolution of dilatant faults in fractured rocks using analogue models with cohesive powder. The upper layer contains pre-formed joint sets, and we vary the angle between joints and a rigid basement fault in our experiments. Analogue models were carried out in a manually driven deformation box (30x28x20 cm) with a 60° dipping pre-defined basement fault and 4.5 cm of displacement. To produce open joints prior to faulting, sheets of paper were mounted in the box to a depth of 5 cm at a spacing of 2.5 cm. Powder was then sieved into the box, embedding the paper almost entirely (column height of 19 cm), and the paper was removed. We tested the influence of different angles between the strike of the basement fault and the joint set (joint fault (JF) angles of 0°, 4°, 8°, 12°, 16°, 20°, and 25°). During deformation we captured structural information by time-lapse photography that allows particle imaging velocimetry analyses (PIV) to detect localized deformation at every increment of displacement. Post-mortem photogrammetry preserves the final 3-dimensional structure of the fault zone. Results show robust structural features in models: damage zone width increases by about 50 % and the number of secondary fractures within this zone by more than 100 % with increasing JF-angle. Interestingly, the map-view area fraction of open gaps increases by only 3%. Secondary joints and fault step-overs are oriented at a high angle to the primary joint orientation. Due to the length of the pre-existing open joints, areas far beyond the fractured regions are connected to the system. In contrast

  11. Smooth random surfaces from tight immersions?

    International Nuclear Information System (INIS)

    Baillie, C.F.; Johnston, D.A.

    1994-01-01

    We investigate actions for dynamically triangulated random surfaces that consist of a Gaussian or area term plus the modulus of the Gaussian curvature and compare their behavior with both Gaussian plus extrinsic curvature and ''Steiner'' actions

  12. Evaluation of Tensile Young's Modulus and Poisson's Ratio of a Bi-modular Rock from the Displacement Measurements in a Brazilian Test

    Science.gov (United States)

    Patel, Shantanu; Martin, C. Derek

    2018-02-01

    Unlike metals, rocks show bi-modularity (different Young's moduli and Poisson's ratios in compression and tension). Displacements monitored during the Brazilian test are used in this study to obtain the Young's modulus and Poisson's ratio in tension. New equations for the displacements in a Brazilian test are derived considering the bi-modularity in the stress-strain relations. The digital image correlation technique was used to monitor the displacements of the Brazilian disk flat surface. To validate the Young's modulus and Poisson's ratio obtained from the Brazilian test, the results were compared with the values from the direct tension tests. The results obtained from the Brazilian test were repetitive and within 3.5% of the value obtained from the direct tension test for the rock tested.

  13. Elastic modulus and thermal stress in coating during heat cycling with different substrate shapes

    Science.gov (United States)

    Gaona, Daniel; Valarezo, Alfredo

    2015-09-01

    The elastic modulus of a deposit ( E d) can be obtained by monitoring the temperature (Δ T) and curvature (Δ k) of a one-side coated long plate, namely, a onedimensional (1D) deformation model. The aim of this research is to design an experimental setup that proves whether a 1D deformation model can be scaled for complex geometries. The setup includes a laser displacement sensor mounted on a robotic arm capable of scanning a specimen surface and measuring its deformation. The reproducibility of the results is verified by comparing the present results with Stony Brook University Laboratory's results. The Δ k-Δ T slope error is less than 8%, and the E d estimation error is close to 2%. These values reveal the repeatability of the experiments. Several samples fabricated with aluminum as the substrate and 100MXC nanowire (Fe and Cr alloy) as the deposit are analyzed and compared with those in finite element (FE) simulations. The linear elastic behavior of 1D (flat long plate) and 2D (squared plate) specimens during heating/cooling cycles is demonstrated by the high linearity of all Δ k-Δ T curves (over 97%). The E d values are approximately equal for 1D and 2D analyses, with a median of 96 GPa and standard deviation of 2 GPa. The correspondence between the experimental and simulated results for the 1D and 2D specimens reveals that deformation and thermal stress in coated specimens can be predicted regardless of specimen geometry through FE modeling and by using the experimental value of E d. An example of a turbine-bladeshaped substrate is presented to validate the approach.

  14. Terapia celular na cardiomiopatia dilatada Cell therapy in dilated cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Helena Furtado Martino

    2006-05-01

    Full Text Available Homem de 41 anos em insuficiência cardíaca sistólica, CF III NYHA, estágio clínico C, por cardiomiopatia dilatada, foi submetido ao transplante autólogo da fração mononuclear da medula óssea, via sistema arterial coronariano, através de cateterismo cardíaco. Dois meses após o procedimento, houve diminuição do BNP plasmático, diminuição da área cardíaca ao estudo radiológico do tórax e à ressonância nuclear magnética. O ecocardiograma demonstrou diminuição do fluxo regurgitante secundário a dilatação do anel mitral. Na ergoespirometria houve melhor desempenho, com aumento do consumo máximo de oxigênio, sendo possível redução da terapêutica medicamentosa. A ausência de eventos adversos caracterizados por: instabilidade clínica/hemodinâmica, alteração enzimática ou eletrocardiográfica apontam para segurança e exeqüibilidade deste procedimento realizado e descrito com pioneirismo na cardiomiopatia dilatada.A forty-one-year-old male with systolic heart failure, FC-III NYHA, clinical stage C due to dilated cardiomyopathy was submitted to an autologous transplant of the mononuclear fraction of bone marrow via coronary artery system through heart catheterism. Two months after the procedure, there was a decrease in plasma BNP and cardiac area reduction at the thorax X-ray and nuclear magnetic resonance. The echocardiogram showed decrease of the secondary regurgitation and mitral ring dilatation. There was a better performance at the ergospirometry, with increase of the maximum oxygen consumption and consequent reduction in drug therapy. The absence of adverse events characterized by clinical/hemodynamic instability, enzymatic alteration or electrocardiogram demonstrate the safety and feasibility of this procedure carried out and described with pioneering spirit in dilated cardiomyopathy.

  15. An entropy spring model for the Young's modulus change of biodegradable polymers during biodegradation.

    Science.gov (United States)

    Wang, Ying; Han, Xiaoxiao; Pan, Jingzhe; Sinka, Csaba

    2010-01-01

    This paper presents a model for the change in Young's modulus of biodegradable polymers due to hydrolysis cleavage of the polymer chains. The model is based on the entropy spring theory for amorphous polymers. It is assumed that isolated polymer chain cleavage and very short polymer chains do not affect the entropy change in a linear biodegradable polymer during its deformation. It is then possible to relate the Young's modulus to the average molecular weight in a computer simulated hydrolysis process of polymer chain sessions. The experimental data obtained by Tsuji [Tsuji, H., 2002. Autocatalytic hydrolysis of amorphous-made polylactides: Effects of L-lactide content, tacticity, and enantiomeric polymer blending. Polymers 43, 1789-1796] for poly(L-lactic acid) and poly(D-lactic acid) are examined using the model. It is shown that the model can provide a common thread through Tsuji's experimental data. A further numerical case study demonstrates that the Young's modulus obtained using very thin samples, such as those obtained by Tsuji, cannot be directly used to calculate the load carried by a device made of the same polymer but of various thicknesses. This is because the Young's modulus varies significantly in a biodegradable device due to the heterogeneous nature of the hydrolysis reaction. The governing equations for biodegradation and the relation between the Young's modulus and average molecular weight can be combined to calculate the load transfer from a degrading device to a healing bone.

  16. Actin cytoskeleton contributes to the elastic modulus of embryonic tendon during early development.

    Science.gov (United States)

    Schiele, Nathan R; von Flotow, Friedrich; Tochka, Zachary L; Hockaday, Laura A; Marturano, Joseph E; Thibodeau, Jeffrey J; Kuo, Catherine K

    2015-06-01

    Tendon injuries are common and heal poorly. Strategies to regenerate or replace injured tendons are challenged by an incomplete understanding of normal tendon development. Our previous study showed that embryonic tendon elastic modulus increases as a function of developmental stage. Inhibition of enzymatic collagen crosslink formation abrogated increases in tendon elastic modulus at late developmental stages, but did not affect increases in elastic modulus of early stage embryonic tendons. Here, we aimed to identify potential contributors to the mechanical properties of these early stage embryonic tendons. We characterized tendon progenitor cells in early stage embryonic tendons, and the influence of actin cytoskeleton disruption on tissue elastic modulus. Cells were closely packed in embryonic tendons, and did not change in density during early development. We observed an organized network of actin filaments that seemed contiguous between adjacent cells. The actin filaments exhibited a crimp pattern with a period and amplitude that matched the crimp of collagen fibers at each developmental stage. Chemical disruption of the actin cytoskeleton decreased tendon tissue elastic modulus, measured by atomic force microscopy. Our results demonstrate that early developmental stage embryonic tendons possess a well organized actin cytoskeleton network that contributes significantly to tendon tissue mechanical properties. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  17. Ultrasound estimation and FE analysis of elastic modulus of Kelvin foam

    International Nuclear Information System (INIS)

    Kim, Nohyu; Yang, Seung Yong

    2016-01-01

    The elastic modulus of a 3D-printed Kelvin foam plate is investigated by measuring the acoustic wave velocity of 1 MHz ultrasound. An isotropic tetrakaidecahedron foam with 3 mm unit cell is designed and printed layer upon layer to fabricate a Kelvin foam plate of 14 mm thickness with a 3D CAD/printer using ABS plastic. The Kelvin foam plate is completely filled with paraffin wax for impedance matching, so that the acoustic wave may propagate through the porous foam plate. The acoustic wave velocity of the foam plate is measured using the time-of-flight (TOF) method and is used to calculate the elastic modulus of the Kelvin foam plate based on acousto-elasticity. Finite element method (FEM) and micromechanics is applied to the Kelvin foam plate to calculate the theoretical elastic modulus using a non-isotropic tetrakaidecahedron model. The predicted elastic modulus of the Kelvin foam plate from FEM and micromechanics model is similar, which is only 3-4% of the bulk material. The experimental value of the elastic modulus from the ultrasonic method is approximately twice as that of the numerical and theoretical methods because of the flexural deformation of the cell edges neglected in the ultrasonic method

  18. Ultrasound estimation and FE analysis of elastic modulus of Kelvin foam

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Nohyu; Yang, Seung Yong [School of Mechatronics Engineering, Korea University of Technology and Education, Cheonan (Korea, Republic of)

    2016-02-15

    The elastic modulus of a 3D-printed Kelvin foam plate is investigated by measuring the acoustic wave velocity of 1 MHz ultrasound. An isotropic tetrakaidecahedron foam with 3 mm unit cell is designed and printed layer upon layer to fabricate a Kelvin foam plate of 14 mm thickness with a 3D CAD/printer using ABS plastic. The Kelvin foam plate is completely filled with paraffin wax for impedance matching, so that the acoustic wave may propagate through the porous foam plate. The acoustic wave velocity of the foam plate is measured using the time-of-flight (TOF) method and is used to calculate the elastic modulus of the Kelvin foam plate based on acousto-elasticity. Finite element method (FEM) and micromechanics is applied to the Kelvin foam plate to calculate the theoretical elastic modulus using a non-isotropic tetrakaidecahedron model. The predicted elastic modulus of the Kelvin foam plate from FEM and micromechanics model is similar, which is only 3-4% of the bulk material. The experimental value of the elastic modulus from the ultrasonic method is approximately twice as that of the numerical and theoretical methods because of the flexural deformation of the cell edges neglected in the ultrasonic method.

  19. Characterization of multilayer nitride coatings by electron microscopy and modulus mapping

    International Nuclear Information System (INIS)

    Pemmasani, Sai Pramod; Rajulapati, Koteswararao V.; Ramakrishna, M.; Valleti, Krishna; Gundakaram, Ravi C.; Joshi, Shrikant V.

    2013-01-01

    This paper discusses multi-scale characterization of physical vapour deposited multilayer nitride coatings using a combination of electron microscopy and modulus mapping. Multilayer coatings with a triple layer structure based on TiAlN and nanocomposite nitrides with a nano-multilayered architecture were deposited by Cathodic arc deposition and detailed microstructural studies were carried out employing Energy Dispersive Spectroscopy, Electron Backscattered Diffraction, Focused Ion Beam and Cross sectional Transmission Electron Microscopy in order to identify the different phases and to study microstructural features of the various layers formed as a result of the deposition process. Modulus mapping was also performed to study the effect of varying composition on the moduli of the nano-multilayers within the triple layer coating by using a Scanning Probe Microscopy based technique. To the best of our knowledge, this is the first attempt on modulus mapping of cathodic arc deposited nitride multilayer coatings. This work demonstrates the application of Scanning Probe Microscopy based modulus mapping and electron microscopy for the study of coating properties and their relation to composition and microstructure. - Highlights: • Microstructure of a triple layer nitride coating studied at multiple length scales. • Phases identified by EDS, EBSD and SAED (TEM). • Nanolayered, nanocomposite structure of the coating studied using FIB and TEM. • Modulus mapping identified moduli variation even in a nani-multilayer architecture

  20. The effective modulus of super carbon nanotubes predicted by molecular structure mechanics.

    Science.gov (United States)

    Li, Ying; Qiu, Xinming; Yang, Fan; Wang, Xi-Shu; Yin, Yajun

    2008-06-04

    A super carbon nanotube (ST) is a kind of hierarchical structure constructed from carbon nanotubes (named as CNT arm tubes). With the detailed construction of a Y-junction considered, the effective mechanical properties of ST structures are studied by the molecular structure mechanics (MSM) method. The Young's modulus and shear modulus of STs are found to depend mainly on the aspect ratio of CNT arm tubes instead of the chirality of the ST. A scale law is adopted to express the relation between the effective modulus (Young's modulus or shear modulus) and the aspect ratio of the CNT arm tubes. The Poisson's ratio of the ST is affected by both the aspect ratio of the CNT arm tubes and the chirality of the ST. The deformation of the ST comes from both the bending and the stretching of the CNT arm tubes. The Y-junction acts as an reinforcement phase to make the bending and stretching couple together and induce large linearity in ST structures.

  1. In vivo 3-dimensional Magnetic Resonance Wall Shear Stress Estimation in Ascending Aortic Dilatation

    Science.gov (United States)

    Bieging, Erik T.; Frydrychowicz, Alex; Wentland, Andrew; Landgraf, Benjamin R.; Johnson, Kevin M.; Wieben, Oliver; François, Christopher J.

    2011-01-01

    Purpose To estimate surface-based wall shear stress (WSS) and evaluate flow patterns in ascending aortic dilatation (AscAD) using a high-resolution, time-resolved, three-dimensional (3D), three-directional velocity encoded, radially undersampled phase contrast magnetic resonance sequence (4D PC-MRI). Materials and Methods 4D PC-MRI was performed in 11 patients with AscAD (46.3±22.0 years) and 10 healthy volunteers (32.9±13.4 years) after written informed consent and IRB-approval. Following manual vessel wall segmentation of the ascending aorta (MATLAB, The Mathworks, Natick, MA), a 3D surface was created using spline interpolation. Spatial WSS variation based on surface division in 12 segments and temporal variation were evaluated in AscAD and normal aortas. Visual analysis of flow patterns was performed based on streamlines and particle traces using EnSight (v9.0, CEI, Apex, NC). Results AscAD was associated with significantly increased diastolic WSS, decreased systolic to diastolic WSS ratio, and delayed onset of peak WSS (all P wall of the ascending aorta. Vortical flow with highest velocities along the anterior wall and increased helical flow during diastole were observed in AscAD compared to controls. Conclusion Changes in WSS in the ascending aorta of AscAD correspond to observed alterations in flow patterns compared to controls. PMID:21563242

  2. Comparison of Immune Profiles in Fetal Hearts with Idiopathic Dilated Cardiomyopathy, Maternal Autoimmune-Associated Dilated Cardiomyopathy and the Normal Fetus.

    Science.gov (United States)

    Nield, Lynne E; von Both, Ingo; Popel, Najla; Strachan, Kate; Manlhiot, Cedric; Shannon, Patrick; McCrindle, Brian W; Atkinson, Adelle; Miner, Steven E S; Jaeggi, Edgar T; Taylor, Glenn P

    2016-02-01

    The etiology of idiopathic dilated cardiomyopathy (iDCM) remains unknown. Immune therapies have improved outcome in fetuses with DCM born to mothers with autoimmune disease (aDCM). The purpose of this retrospective study was to compare the myocardial B and T cell profiles in fetuses and neonates with idiopathic DCM (iDCM) versus autoimmune-mediated DCM (aDCM) and to describe the normal cell maturation within the human fetal myocardium. Of 60 fetal autopsy cases identified from institutional databases, 10 had aDCM (18-38 weeks), 12 iDCM (19-37 weeks) and 38 had normal hearts (11-40 weeks). Paraffin-embedded myocardium sections were stained for all lymphocyte (CD45), B cells (CD20, CD79a), T cells (CD3, CD4, CD7, CD8) and monocyte (CD68) surface markers. Two independent, blinded cell counts were performed. Normal hearts expressed all B and T cell markers in a bimodal fashion, with peaks at 22 and 37 weeks of gestation. The aDCM cohort was most distinct from normal hearts, with less overall T cell markers [EST -9.1 (2.6) cells/mm(2), p = 0.001], CD4 [EST -2.0 (0.6), p = 0.001], CD3 [EST -3.9 (1.0), p cell markers [EST -4.9 (1.8), p = 0.01] and CD79a counts [EST -2.3 (0.9), p = 0.01]. The iDCM group had less overall B cell markers [EST -4.0 (1.8), p = 0.03] and CD79a [EST -1.7 (0.9), p = 0.05], but no difference in T cell markers. Autoimmune-mediated DCM fetuses have less B and T cell markers, whereas iDCM fetuses have less B cell markers compared with normal fetal hearts. The fetal immune system may play a role in the normal development of the heart and evolution of dilated cardiomyopathy.

  3. Reproducibility and genital sparing with a vaginal dilator used for female anal cancer patients.

    Science.gov (United States)

    Briere, Tina Marie; Crane, Christopher H; Beddar, Sam; Bhosale, Priya; Mok, Henry; Delclos, Marc E; Krishnan, Sunil; Das, Prajnan

    2012-08-01

    Acute vulvitis, acute urethritis, and permanent sexual dysfunction are common among patients treated with chemoradiation for squamous cell carcinoma of the anal canal. Avoidance of the genitalia may reduce sexual dysfunction. A vaginal dilator may help delineate and displace the vulva and lower vagina away from the primary tumor. The goal of this study was to evaluate the positional reproducibility and vaginal sparing with the use of a vaginal dilator. Ten female patients treated with IMRT for anal cancer were included in this study. A silicone vaginal dilator measuring 29 mm in diameter and 114 mm in length was inserted into the vagina before simulation and each treatment. The reproducibility of dilator placement was investigated with antero-posterior and lateral images acquired daily. Weekly cone beam CT (CBCT) imaging was used to confirm coverage of the GTV, which was typically posterior and inferior to the dilator apex. Finally, a planning study was performed to compare the vaginal doses for these 10 patients to a comparable group of 10 female patients who were treated for anal cancer with IMRT without vaginal dilators. The absolute values of the location of the dilator apex were 7.0 ± 7.8mm in the supero-inferior direction, 7.5 ± 5.5 mm in the antero-posterior, and 3.8 ± 3.1mm in the lateral direction. Coverage of the GTV and CTV was confirmed from CBCT images. The mean dose to the vagina was lower by 5.5 Gy, on average, for the vaginal dilator patients, compared to patients treated without vaginal dilators. The vaginal dilator tended to be inserted more inferiorly during treatment than during simulation. For these ten patients, this did not compromise tumor coverage. Combined with IMRT treatment planning, use of a vaginal dilator could allow for maximum sparing of female genitalia for patients undergoing radiation therapy for anal cancer. Published by Elsevier Ireland Ltd.

  4. Cardiovascular genetics: technological advancements and applicability for dilated cardiomyopathy.

    Science.gov (United States)

    Kummeling, G J M; Baas, A F; Harakalova, M; van der Smagt, J J; Asselbergs, F W

    2015-07-01

    Genetics plays an important role in the pathophysiology of cardiovascular diseases, and is increasingly being integrated into clinical practice. Since 2008, both capacity and cost-efficiency of mutation screening of DNA have been increased magnificently due to the technological advancement obtained by next-generation sequencing. Hence, the discovery rate of genetic defects in cardiovascular genetics has grown rapidly and the financial threshold for gene diagnostics has been lowered, making large-scale DNA sequencing broadly accessible. In this review, the genetic variants, mutations and inheritance models are briefly introduced, after which an overview is provided of current clinical and technological applications in gene diagnostics and research for cardiovascular disease and in particular, dilated cardiomyopathy. Finally, a reflection on the future perspectives in cardiogenetics is given.

  5. Atlas of the clinical genetics of human dilated cardiomyopathy

    DEFF Research Database (Denmark)

    Haas, Jan; Frese, Karen S; Peil, Barbara

    2015-01-01

    AIM: Numerous genes are known to cause dilated cardiomyopathy (DCM). However, until now technological limitations have hindered elucidation of the contribution of all clinically relevant disease genes to DCM phenotypes in larger cohorts. We now utilized next-generation sequencing to overcome......, leading to 99.1% coverage of the target region with at least 50-fold and a mean read depth of 2415. In this well characterized cohort, we find the highest number of known cardiomyopathy mutations in plakophilin-2, myosin-binding protein C-3, and desmoplakin. When we include yet unknown but predicted......: This is to our knowledge, the first study that comprehensively investigated the genetics of DCM in a large-scale cohort and across a broad gene panel of the known DCM genes. Our results underline the high analytical quality and feasibility of Next-Generation Sequencing in clinical genetic diagnostics and provide...

  6. The inverse problem of estimating the gravitational time dilation

    Energy Technology Data Exchange (ETDEWEB)

    Gusev, A. V., E-mail: avg@sai.msu.ru; Litvinov, D. A.; Rudenko, V. N. [Moscow State University, Sternberg Astronomical Institute (Russian Federation)

    2016-11-15

    Precise testing of the gravitational time dilation effect suggests comparing the clocks at points with different gravitational potentials. Such a configuration arises when radio frequency standards are installed at orbital and ground stations. The ground-based standard is accessible directly, while the spaceborne one is accessible only via the electromagnetic signal exchange. Reconstructing the current frequency of the spaceborne standard is an ill-posed inverse problem whose solution depends significantly on the characteristics of the stochastic electromagnetic background. The solution for Gaussian noise is known, but the nature of the standards themselves is associated with nonstationary fluctuations of a wide class of distributions. A solution is proposed for a background of flicker fluctuations with a spectrum (1/f){sup γ}, where 1 < γ < 3, and stationary increments. The results include formulas for the error in reconstructing the frequency of the spaceborne standard and numerical estimates for the accuracy of measuring the relativistic redshift effect.

  7. Pathomorphological Changes of the Myocardium in Canine Dilated Cardiomyopathy (DCM

    Directory of Open Access Journals (Sweden)

    Janus Izabela

    2015-04-01

    Full Text Available The study was conducted on ventricular and atrial wall preparations from 11 dogs with clinically diagnosed dilated cardiomyopathy. After fixation, the specimens were stained with haematoxylin and eosin and Masson-Goldner trichrome technique. Parenchymal changes (fibrosis and fatty infiltration, vascular changes (congestion and coronary vessel wall hypertrophy, degenerative changes (loss of striation, changes in cardiomycyte and nuclei structure, and presence of inflammatory infiltrates (mononuclear and polynuclear were estimated. Complex histological changes in both ventricular and atrial muscles were shown. It was not determined whether the processes occurring in the myocardium have a primary character, or are a consequence of developing heart failure. Such issues will be put under further and more detailed examination.

  8. Developmental dilatation of Virchow-Robin spaces: a genetic disorder?

    Science.gov (United States)

    Bruna, Anne-Laure; Martins, Ilda; Husson, Beatrice; Landrieu, Pierre

    2009-10-01

    In childhood, widening of Virchow-Robin spaces is rarely secondary to specific progressive disorders, but more often appears in poorly characterized developmental conditions. From data collected in a neuropediatric department, we examined whether clinical data associated with "constitutional widening of Virchow-Robin spaces" allowed delineation of recognizable entities. Signs in 10 patients, mostly boys, suggested nonspecific cerebral dysfunctions, e.g., developmental delay, nonspecific epilepsy, headaches, or benign macrocephaly. Spaces were sometimes round, subsequently mimicking microcystic malacic lesions. In two patients, abnormal magnetic resonance imaging signals were evident in white matter contiguous to widened perivascular spaces, suggesting a broader disorder of fluid exchanges. Four cases occurred in two sibships. In two families, other patients exhibited early developmental difficulties. Long-term clinical and magnetic resonance imaging surveillance will clarify which cases of primary Virchow-Robin space dilatation imply a benign prognosis. Performance of magnetic resonance imaging on any relative exhibiting minor neuropsychologic handicaps would permit estimations of real genetic incidence.

  9. Prenatal diagnostic evaluation of fetal ventricular dilatation by MRI

    International Nuclear Information System (INIS)

    Kawabata, Ichiro; Tamaya, Teruhiko; Iwata, Tatsuo; Ando, Takashi; Yamada, Hiromu

    1992-01-01

    Recent advances in MRI have contributed to the antenatal confirmatory diagnosis of fetal anomalies, especially in the fetal brain and central nervous system. In this study, eight infants with fetal ventricular dilatation, suggested by prenatal ultrasonography, were evaluated with confirmatory diagnosis by MRI (SIGNA; General Electric Company, 1.5 tesla). These anomalies were demonstrated at 19 to 36 weeks by ultrasonography. One of the eight died in utero at 22 weeks of gestation, another one day after birth (33 weeks of gestation). Two were delivered by Cesarean section. It has been proved that clear and effective images can be obtained by mother's walking without sedative drugs. Fetal MRI gave clear images not only in fetal horizontal section, but also in sagittal section, which is usually difficult to obtain by ultrasonography. Confirmatory diagnosis of eight cases were obtained by MRI. Fetal MRI can provide an effective prenatal diagnosis, especially in cases of fetal brain anomaly, even when compared with postnatal CT findings. (author)

  10. Network Intrusion Detection through Stacking Dilated Convolutional Autoencoders

    Directory of Open Access Journals (Sweden)

    Yang Yu

    2017-01-01

    Full Text Available Network intrusion detection is one of the most important parts for cyber security to protect computer systems against malicious attacks. With the emergence of numerous sophisticated and new attacks, however, network intrusion detection techniques are facing several significant challenges. The overall objective of this study is to learn useful feature representations automatically and efficiently from large amounts of unlabeled raw network traffic data by using deep learning approaches. We propose a novel network intrusion model by stacking dilated convolutional autoencoders and evaluate our method on two new intrusion detection datasets. Several experiments were carried out to check the effectiveness of our approach. The comparative experimental results demonstrate that the proposed model can achieve considerably high performance which meets the demand of high accuracy and adaptability of network intrusion detection systems (NIDSs. It is quite potential and promising to apply our model in the large-scale and real-world network environments.

  11. Full deflection profile calculation and Young’s modulus optimisation for engineered high performance materials

    Science.gov (United States)

    Farsi, A.; Pullen, A. D.; Latham, J. P.; Bowen, J.; Carlsson, M.; Stitt, E. H.; Marigo, M.

    2017-04-01

    New engineered materials have critical applications in different fields in medicine, engineering and technology but their enhanced mechanical performances are significantly affected by the microstructural design and the sintering process used in their manufacture. This work introduces (i) a methodology for the calculation of the full deflection profile from video recordings of bending tests, (ii) an optimisation algorithm for the characterisation of Young’s modulus, (iii) a quantification of the effects of optical distortions and (iv) a comparison with other standard tests. The results presented in this paper show the capabilities of this procedure to evaluate the Young’s modulus of highly stiff materials with greater accuracy than previously possible with bending tests, by employing all the available information from the video recording of the tests. This methodology extends to this class of materials the possibility to evaluate both the elastic modulus and the tensile strength with a single mechanical test, without the need for other experimental tools.

  12. A Regev-Type Fully Homomorphic Encryption Scheme Using Modulus Switching

    Science.gov (United States)

    Chen, Zhigang; Wang, Jian; Song, Xinxia

    2014-01-01

    A critical challenge in a fully homomorphic encryption (FHE) scheme is to manage noise. Modulus switching technique is currently the most efficient noise management technique. When using the modulus switching technique to design and implement a FHE scheme, how to choose concrete parameters is an important step, but to our best knowledge, this step has drawn very little attention to the existing FHE researches in the literature. The contributions of this paper are twofold. On one hand, we propose a function of the lower bound of dimension value in the switching techniques depending on the LWE specific security levels. On the other hand, as a case study, we modify the Brakerski FHE scheme (in Crypto 2012) by using the modulus switching technique. We recommend concrete parameter values of our proposed scheme and provide security analysis. Our result shows that the modified FHE scheme is more efficient than the original Brakerski scheme in the same security level. PMID:25093212

  13. Using the ultrasound and instrumented indentation techniques to measure the elastic modulus of engineering materials

    International Nuclear Information System (INIS)

    Meza, J. M.; Franco, E. E.; Farias, M. C. M.; Buiochi, F.; Souza, R. M.; Cruz, J.

    2008-01-01

    Currently, the acoustic and nano indentation techniques are two of the most used techniques for materials elastic modulus measurement. In this article fundamental principles and limitations of both techniques are shown and discussed. Last advances in nano indentation technique are also reviewed. an experimental study in ceramic, metallic, composite and single crystals was also done. Results shown that ultrasonic technique is capable to provide results in agreement with those reported in literature. However, ultrasonic technique does not allow measuring the elastic modulus of some small samples and single crystals. On the other hand, the nano indentation technique estimates the elastic modulus values in reasonable agreement with those measured by acoustic methods, particularly in amorphous materials, while in some policristaline materials some deviation from expected values was obtained. (Author) 29 refs

  14. Multi-modulus algorithm based on global artificial fish swarm intelligent optimization of DNA encoding sequences.

    Science.gov (United States)

    Guo, Y C; Wang, H; Wu, H P; Zhang, M Q

    2015-12-21

    Aimed to address the defects of the large mean square error (MSE), and the slow convergence speed in equalizing the multi-modulus signals of the constant modulus algorithm (CMA), a multi-modulus algorithm (MMA) based on global artificial fish swarm (GAFS) intelligent optimization of DNA encoding sequences (GAFS-DNA-MMA) was proposed. To improve the convergence rate and reduce the MSE, this proposed algorithm adopted an encoding method based on DNA nucleotide chains to provide a possible solution to the problem. Furthermore, the GAFS algorithm, with its fast convergence and global search ability, was used to find the best sequence. The real and imaginary parts of the initial optimal weight vector of MMA were obtained through DNA coding of the best sequence. The simulation results show that the proposed algorithm has a faster convergence speed and smaller MSE in comparison with the CMA, the MMA, and the AFS-DNA-MMA.

  15. Studies on resilient modulus value from cyclic loading tests for cohesive soil

    Directory of Open Access Journals (Sweden)

    Sas Wojciech

    2017-06-01

    Full Text Available In this article the cyclic CBR test as a reference method in determination of resilient modulus (Mr is confronted with results of cyclic triaxial and unconfined uniaxial cyclic test. The main idea of conducted experiments is establish relationship between cyclic loading tests in testing of natural subsoil and road materials. The article shows results of investigation on cohesive soil, namely sandy silty clay, commonly problematic soil in Poland. The results of repeated loading triaxial test resilient modulus were displayed in order to compare them with cyclic CBR test results by using the Mr–Ө model. Some empirical correlation between factors obtained from triaxial test or uniaxial unconfined cyclic test and cyclic CBR test was introduced here. The behavior of resilient modulus was also examined in this paper.

  16. Calculation of the shear modulus of a two-dimensional vortex lattice

    Science.gov (United States)

    ŠáŠik, R.; Stroud, D.

    1994-06-01

    We have calculated the temperature-dependent shear modulus μ(T) of a vortex lattice in a two-dimensional superconductor. We include fluctuations by expanding the Ginzburg-Landau free-energy functional in states from the lowest Landau level, and evaluate the shear modulus by standard Monte Carlo techniques for rectangular samples containing up to 224 vortices. At the thermodynamic melting transition, which is apparently first order as found by previous workers, the shear modulus falls from a finite value in the solid phase to zero in the liquid. Despite the first-order transition, the magnitude of the drop may be near the universal value envisioned in dislocation-unbinding theories.

  17. A Model of Temperature-Dependent Young's Modulus for Ultrahigh Temperature Ceramics

    Directory of Open Access Journals (Sweden)

    Weiguo Li

    2011-01-01

    Full Text Available Based on the different sensitivities of material properties to temperature between ultrahigh temperature ceramics (UHTCs and traditional ceramics, the original empirical formula of temperature-dependent Young's modulus of ceramic materials is unable to describe the temperature dependence of Young's modulus of UHTCs which are used as thermal protection materials. In this paper, a characterization applied to Young's modulus of UHTC materials under high temperature which is revised from the original empirical formula is established. The applicable temperature range of the characterization extends to the higher temperature zone. This study will provide a basis for the characterization for strength and fracture toughness of UHTC materials and provide theoretical bases and technical reserves for the UHTC materials' design and application in the field of spacecraft.

  18. Effects of SBS Configuration on Performance of High Modulus Bitumen Based on Dynamic Mechanical Analysis

    Directory of Open Access Journals (Sweden)

    Ming Liang

    2016-07-01

    Full Text Available High modulus bitumens modified by polystyrene-block-polybutadiene-block-polystyrene (SBS with different molecular structure were investigated on dynamic shear rheometer and fluorescence microscopy to evaluate viscoelastic properties and morphology of binders. The results shows that storage modulus (G’ is obviously less than loss modulus (G”, which means viscous behaviour of bitumen is dominant, and anti-rutting factor (G* ⁄ sin δ is markedly enhanced by star SBS than by linear SBS. The morphology indicated that star SBS improved the softening point more obviously, tending to form a cross-linked network in bitumen. As for linear SBS, it is dispersed in bitumen in the form of globules and enhances the ductility of binder.

  19. Analysis of discontinuities influence on the differences between static and dynamic elastic modulus of composite materials

    Science.gov (United States)

    Sava, Mihaela; Hadǎr, Anton; Pǎrǎuşanu, Ioan; Petrescu, Horia-Alexandru; Baciu, Florin; Marinel, Stǎnescu Marius

    2016-06-01

    The influence of discontinuities is important for a correct determination of static and dynamic elastic characteristics of the material. In this paper we presented differences arising between the elastic modulus static and dynamic, laminated composite materials reinforced with carbon fiber, aramid and carbon-aramid, depending on the non-uniformity coefficient. For the study were determined static elastic modulus by carrying out traction tests and dynamic elastic modulus by determining the vibration frequency, on specimens of each type of material with and without discontinuities [1]. The elastic properties of composite materials resistance and can be influenced by various defects that arise from technological manufacturing process. This is important for the production of large series of parts of fiber-reinforced composite material, the fibers in the matrix distribution is not uniform. Studies on the mechanical behavior of composites with random distribution of fabrics are made in [2].

  20. D-term contributions to the mixed modulus-anomaly mediated supersymmetry breaking

    International Nuclear Information System (INIS)

    Fukuyama, Takeshi; Kikuchi, Tatsuru; Okada, Nobuchika

    2006-01-01

    We investigate effects of D-term contributions to the mixed modulus-anomaly mediated supersymmetry breaking scenario. In the original scenario, the tachyonic slepton problem in the pure anomaly mediated supersymmetry breaking is cured by modulus contributions. We generalize the scenario so as to include contributions from the D-terms of U(1) Y and the gauged U(1) B-L which is motivated in a grand unified theory based on a higher rank gauge group such as SO(10). As a consequence of additional D-term contributions to scalar masses, we obtain various soft supersymmetry breaking mass spectra, which are different from those obtained in the conventional mixed modulus-anomaly mediated supersymmetry breaking. Especially, we find that the lightest superpartner (LSP) neutralinos can be various types, such as higgsino-like, wino-like and bino-like degenerating with the next LSP sfermions

  1. Magnetic-field-dependent shear modulus of a magnetorheological elastomer based on natural rubber

    Science.gov (United States)

    Yang, In-Hyung; Yoon, Ji-Hyun; Jeong, Jae-Eun; Jeong, Un-Chang; Kim, Jin-Su; Chung, Kyung Ho; Oh, Jae-Eung

    2013-01-01

    A magnetorheological elastomer (MRE) is a smart material that has a reversible and variable modulus in a magnetic field. Natural rubber, which has better physical properties than silicone matrices, was used as a matrix in the fabrication of the MREs used in this study. Carbonyl iron powder (CIP), which has a rapid magnetic reaction, was selected as a magnetic material to generate the magnetic-field-dependent modulus in the MREs. The MRE specimens were cured in an anisotropic mold, which could be used to induce a uniaxial magnetic field via permanent magnets, to control the orientation of the CIP, and the shear modulus of the MREs was evaluated under a magnetic field induced by using a magnetic flux generator (MFG). Because the use of a conventional evaluation system to determine the magnetic-field-dependent shear modulus of the MREs was difficult, an evaluation system based on single degree-of-freedom vibration and electromagnetics that included an MFG, which is a device that generates a magnetic field via a variable induced current, was designed. An electromagnetic finite element method (FEM) analysis and design of experiments (DoE) techniques were employed to optimize the magnetic flux density generated by the MFG. The optimized system was verified over the range to determine the magnetic flux density generated by the MFG in order to use a magnetic circuit analysis to identify the existence of magnetic saturation. A variation in the shear modulus was observed with increasing CIP volume fraction and induced current. The experimental results revealed that the maximum variation in the shear modulus was 76.3% for 40 vol% CIP at an induced current of 4 A. With these results, the appropriate CIP volume fraction, induced current, and design procedure of the MFG can be proposed as guidelines for applications of MREs based on natural rubber.

  2. On the relationship between indentation hardness and modulus, and the damage resistance of biological materials.

    Science.gov (United States)

    Labonte, David; Lenz, Anne-Kristin; Oyen, Michelle L

    2017-07-15

    The remarkable mechanical performance of biological materials is based on intricate structure-function relationships. Nanoindentation has become the primary tool for characterising biological materials, as it allows to relate structural changes to variations in mechanical properties on small scales. However, the respective theoretical background and associated interpretation of the parameters measured via indentation derives largely from research on 'traditional' engineering materials such as metals or ceramics. Here, we discuss the functional relevance of indentation hardness in biological materials by presenting a meta-analysis of its relationship with indentation modulus. Across seven orders of magnitude, indentation hardness was directly proportional to indentation modulus. Using a lumped parameter model to deconvolute indentation hardness into components arising from reversible and irreversible deformation, we establish criteria which allow to interpret differences in indentation hardness across or within biological materials. The ratio between hardness and modulus arises as a key parameter, which is related to the ratio between irreversible and reversible deformation during indentation, the material's yield strength, and the resistance to irreversible deformation, a material property which represents the energy required to create a unit volume of purely irreversible deformation. Indentation hardness generally increases upon material dehydration, however to a larger extent than expected from accompanying changes in indentation modulus, indicating that water acts as a 'plasticiser'. A detailed discussion of the role of indentation hardness, modulus and toughness in damage control during sharp or blunt indentation yields comprehensive guidelines for a performance-based ranking of biological materials, and suggests that quasi-plastic deformation is a frequent yet poorly understood damage mode, highlighting an important area of future research. Instrumented

  3. A study of polymer clad resin with higher modulus for high NA fibers

    Science.gov (United States)

    Lee, J. H.; Kwak, S. J.; Yoon, J. W.; Min, K. B.; Kim, M. J.; Kim, S. H.; Oh, S. K.

    2008-11-01

    There has been a rapidly increasing demand for the high numerical aperture (NA) in specialty optical fibers used in recent high power fiber lasers and remote sensing applications. Various polymer clad resins (PCR) have been reported aimed for a low refractive index to achieve a high NA, which resulted in a lower modulus. In this study, we report a novel PCR with a higher modulus whilst maintaining a high NA over 0.44 using newly designed fluorinated oligomer and monomer having low refractive index and high functionality. Some resins prepared various formulations using synthesized oligomers and then compared curing speed.

  4. Subcritical crack growth in an aging plate with variable elastic modulus

    Science.gov (United States)

    Gavrilov, G. V.

    2010-10-01

    The paper addresses subcritical growth of a crack in a thin isotropic plate made of an aging viscoelastic material with time-dependent elastic modulus. The behavior of the material is described by Arutyunyan's creep theory. To simulate fracture, a modified Leonov-Panasyuk-Dugdale model and a critical crack opening displacement criterion are used. An equation describing the subcritical growth of the crack is derived assuming that Poisson's ratio is constant. As an example, the critical loads are determined, and curves of subcritical crack growth are plotted for a specific material. The results are compared with the case of constant elastic modulus

  5. Linear analysis using secants for materials with temperature dependent nonlinear elastic modulus and thermal expansion properties

    Science.gov (United States)

    Pepi, John W.

    2017-08-01

    Thermally induced stress is readily calculated for linear elastic material properties using Hooke's law in which, for situations where expansion is constrained, stress is proportional to the product of the material elastic modulus and its thermal strain. When material behavior is nonlinear, one needs to make use of nonlinear theory. However, we can avoid that complexity in some situations. For situations in which both elastic modulus and coefficient of thermal expansion vary with temperature, solutions can be formulated using secant properties. A theoretical approach is thus presented to calculate stresses for nonlinear, neo-Hookean, materials. This is important for high acuity optical systems undergoing large temperature extremes.

  6. Elastic Modulus Measurement of ORNL ATF FeCrAl Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Zachary T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Terrani, Kurt A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Yamamoto, Yukinori [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-10-01

    Elastic modulus and Poisson’s ratio for a number of wrought FeCrAl alloys, intended for accident tolerant fuel cladding application, are determined via resonant ultrasonic spectroscopy. The results are reported as a function of temperature from room temperature to 850°C. The wrought alloys were in the fully annealed and unirradiated state. The elastic modulus for the wrought FeCrAl alloys is at least twice that of Zr-based alloys over the temperature range of this study. The Poisson’s ratio of the alloys was 0.28 on average and increased very slightly with increasing temperature.

  7. Elastic modulus, thermal expansion, and specific heat at a phase transition

    International Nuclear Information System (INIS)

    Testardi, L.R.

    1975-01-01

    The interrelation of the elastic modulus, thermal-expansion coefficient, and specific heat of a transformed phase relative to the untransformed phase is calculated assuming a particular but useful form of the thermodynamic potential. For second-order phase transitions where this potential applies, measurements of modulus, expansion, and specific heat can yield the general (longitudinal as well as shear) first- and second-order stress (or strain) dependences of the transition temperature and of the order parameter at absolute zero. An exemplary application to one type of phase transition is given

  8. On Young’s modulus profile across anisotropic nonhomogeneous polymeric fibre using automatic transverse interferometric method

    Science.gov (United States)

    Sokkar, T. Z. N.; Shams El-Din, M. A.; El-Tawargy, A. S.

    2012-09-01

    This paper provides the Young's modulus profile across anisotropic nonhomogeneous polymeric fibre using an accurate transverse interferometric method. A mathematical model based on optical and tensile concepts is presented to calculate the mechanical parameter profiles of fibres. The proposed model with the aid of Mach-Zehnder interferometer combined with an automated drawing device are used to determine the Young's modulus profiles for three drawn polypropylene (PP) fibres (virgin, recycled and virgin recycled 50/50). The obtained microinterferograms are analyzed automatically using fringe processor programme to determine the phase distribution.

  9. Association of acetazolamide infusion with headache and cranial artery dilation in healthy volunteers

    DEFF Research Database (Denmark)

    Arngrim, Nanna; Schytz, Henrik Winther; Asghar, Mohammad Sohail

    2014-01-01

    The carbonic anhydrase inhibitor acetazolamide causes extracellular acidosis and dilatation of cerebral arterioles. In this study, we tested the hypothesis that acetazolamide also may induce headache and dilatation of cranial arteries. In a randomized double-blind crossover study design, 12 young...

  10. Endoscopic balloon dilatation as treatment of gastric outlet obstruction in infancy and childhood

    NARCIS (Netherlands)

    Heymans, H. S.; Bartelsman, J. W.; Herweijer, T. J.

    1988-01-01

    The application of balloon dilatation as treatment of gastric outlet obstruction is described. In two infants after inadequate pyloromyotomy and in an 11-year-old boy with surgical damage to the vagus, balloon dilatation was successful and considered a good alternative to surgery in these conditions

  11. Wavelets for Non-expanding Dilations and the Lattice Counting Estimate

    DEFF Research Database (Denmark)

    Bownik, Marcin; Lemvig, Jakob

    2016-01-01

    is not visible for the well-studied class of expanding dilations since the desired lattice counting estimate holds automatically. We show that the lattice counting estimate holds for all dilations A with |detA|≠1 and for almost every lattice Γ with respect to the invariant probability measure on the set...

  12. Emergency Physicians Are Able to Detect Right Ventricular Dilation With Good Agreement Compared to Cardiology.

    Science.gov (United States)

    Rutz, Matt A; Clary, Julie M; Kline, Jeffrey A; Russell, Frances M

    2017-07-01

    Focused cardiac ultrasound (FOCUS) is a useful tool in evaluating patients presenting to the emergency department (ED) with acute dyspnea. Prior work has shown that right ventricular (RV) dilation is associated with repeat hospitalizations and shorter life expectancy. Traditionally, RV assessment has been evaluated by cardiologist-interpreted comprehensive echocardiography. The primary goal of this study was to determine the inter-rater reliability between emergency physicians (EPs) and a cardiologist for determining RV dilation on FOCUS performed on ED patients with acute dyspnea. This was a prospective, observational study at two urban academic EDs; patients were enrolled if they had acute dyspnea and a computed tomographic pulmonary angiogram without acute disease. All patients had an EP-performed FOCUS to assess for RV dilation. RV dilation was defined as an RV to left ventricular ratio greater than 1. FOCUS interpretations were compared to a blinded cardiologist FOCUS interpretation using agreement and kappa statistics. Of 84 FOCUS examinations performed on 83 patients, 17% had RV dilation. Agreement and kappa, for EP-performed FOCUS for RV dilation were 89% (95% confidence interval [CI] 80-95%) and 0.68 (95% CI 0.48-0.88), respectively. Emergency physician sonographers are able to detect RV dilation with good agreement when compared to cardiology. These results support the wider use of EP-performed FOCUS to evaluate for RV dilation in ED patients with dyspnea. © 2017 by the Society for Academic Emergency Medicine.

  13. Primary Pancreatic Lymphoma with Severe Dilatation of Pancreatic Duct: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Heo, Tae Wook; Heo, Suk Hee; Shin, Sang Soo; Jeong, Yong Yeon; Kang, Heoung Keun; Choi, Yoo Duk [Chonnam National University Hospital, Gwangju (Korea, Republic of); Kim, Jin Woong [Chonnam National University Hwasun Hospital, Hwasun (Korea, Republic of)

    2010-04-15

    Primary pancreatic lymphoma is extremely rare and usually consists of a bulky tumor without internal necrosis and severe dilatation of the pancreatic duct. We report the unusual CT and MRI findings of a primary pancreatic lymphoma in a 27-years-old man, associated with severe dilatation of the pancreatic duct, common bile duct, and internal necrosis

  14. Septo-Optic Dysplasia in a Newborn Presenting with Bilateral Dilated and Fixed Pupils

    OpenAIRE

    Jabeen, Mehnaz; Hairfield, Amber; Swischuk, Leonard E.; Jain, Sunil K.

    2016-01-01

    Introduction?We describe a newborn female infant with septo-optic dysplasia (SOD) presenting with bilateral dilated and fixed pupils. Conclusion?Our report is unique because the incidental finding of bilateral dilated and fixed pupils on the newborn exam was the only clinical finding which led to a prompt work-up and eventual diagnosis of SOD.

  15. Levels of muscle enzymes in the serum after esophageal pneumatic dilation in patients with achalasia.

    Science.gov (United States)

    Kimchi, N A; Ron, Y; Abramowich, D; Shirin, H; Scapa, E; Avni, Y

    2005-01-01

    The success rate of pneumatic dilation of the esophagus in patients with achalasia is variable. We aim to assess whether levels of muscle enzymes in the serum are useful for predicting the efficacy of this procedure. Consecutive adults with symptomatic achalasia treated with pneumatic dilation were included. Blood samples were taken immediately before the procedure and after 12, 24 and 32 h. Clinical efficacy of the pneumatic dilation was evaluated on the basis of a symptom score defined prior to, and 2 months after the procedure. Eleven patients underwent 13 pneumatic dilations. In nine patients this was the first dilation attempt. Ten dilations were clinically effective. The study was discontinued after enzyme levels did not show a trend of increase in any of our patients. Moreover, a statistically significant unexpected decrease in creatine phosphokinase values was found 12 h after the procedure, among the 10 successful dilations. We believe that levels of muscle enzymes in the serum cannot predict the efficacy of pneumatic dilation in patients with achalasia.

  16. Pupil Dilation in the Simon Task as a Marker of Conflict Processing

    Directory of Open Access Journals (Sweden)

    Henk eVan Steenbergen

    2013-05-01

    Full Text Available Cognitive demands in response conflict paradigms trigger negative affect and avoidance behavior. However, not all response conflict studies show increases in physiological indices of emotional arousal, such as pupil diameter. In contrast to earlier null-results, this study shows for the first time that small (about 0.02 mm conflict-related pupil dilation can be observed in a Simon task when stimuli do not introduce a light reflex. Results show that response-conflict in Simon trials induces both pupil dilation and reaction-time costs. Moreover, sequential analyses reveal that pupil dilation mirrors the conflict-adaptation pattern observed in reaction time. Although single-trial regression analyses indicated that pupil dilation is likely to reflect more than one process at the same time, in general our findings imply that pupil dilation can be used as an indirect marker of conflict processing.

  17. Frequency and echocardiographic study of dilated cardiomyopathy in children presenting with cardiac failure

    International Nuclear Information System (INIS)

    Khan, M.A.; Mohammad, J.; Hussain, M.

    2004-01-01

    Objective: To evaluate the role of echocardiography in diagnosis of dilated cardiomyopathy as a cause of cardiac failure in children. Design: This was descriptive study. Children presenting with cardiac failure from indoor patients were selected and echocardiography along with chest X- ray, ECG, cardiac enzymes and ASO titre was performed in all patients. Subject: Fifty hospitalized patients with congestive heart failure were selected consecutively from hospitalized patients. Main Outcome: Role of echocardiography in the diagnosis of dilated cardiomyopathy in children presenting with cardiac failure. Results: Out of fifty patients admitted with cardiac failure 27 (54%) cases were found to be dilated cardiomyopathy while congenital heart disease, myocarditis and rheumatic heart disease were found in 12 (24%), 8 (16%) and 3 (6%) cases respectively. Conclusion: Dilated cardiomyopathy is an important cause of cardiac failure in children and echocardiography is an important tool to diagnose and differentiate dilated cardiomyopathy from other causes of cardiac failure. (author)

  18. Postoperative follow-up studies in congenital dilatation of the common bile duct using hepatobiliary scintigraphy

    International Nuclear Information System (INIS)

    Hirobe, Seiichi; Ishida, Haruo; Hayashi, Akira; Kamagata, Shoichiro; Fuchimoto, Yasufumi; Mizuno, Dai; Yano, Tsunehiro; Ishii, Katsumi.

    1995-01-01

    Follow-up studies in congenital dilatation of the common bile duct were done in 20 cases ranging 3 to 20 years after operation. Operative cholangiography had shown dilatation of the intrahepatic bile ducts in 15 patients (75%), of these, 7 patients had cystic dilatation. Five cases of these 7 patients showed prolonged stasis of the nuclide in the cystic dilated intrahepatic bile ducts by 99m Tc-PMT hepatobiliary scintigraphy in the follow-up studies even at 10 years after operation. But none of 20 cases had complication such as intrahepatic lithiasis, cholangitis, and liver dysfunction. Hepatobiliary scintigraphy could provide moderate anatomic and excellent functional information which were useful for these follow-up studies and careful follow-up should be done in the case of cystic dilatation of the intrahepatic bile ducts. (author)

  19. The Eyes Have It: Sex and Sexual Orientation Differences in Pupil Dilation Patterns

    Science.gov (United States)

    Rieger, Gerulf; Savin-Williams, Ritch C.

    2012-01-01

    Recent research suggests profound sex and sexual orientation differences in sexual response. These results, however, are based on measures of genital arousal, which have potential limitations such as volunteer bias and differential measures for the sexes. The present study introduces a measure less affected by these limitations. We assessed the pupil dilation of 325 men and women of various sexual orientations to male and female erotic stimuli. Results supported hypotheses. In general, self-reported sexual orientation corresponded with pupil dilation to men and women. Among men, substantial dilation to both sexes was most common in bisexual-identified men. In contrast, among women, substantial dilation to both sexes was most common in heterosexual-identified women. Possible reasons for these differences are discussed. Because the measure of pupil dilation is less invasive than previous measures of sexual response, it allows for studying diverse age and cultural populations, usually not included in sexuality research. PMID:22870196

  20. The eyes have it: sex and sexual orientation differences in pupil dilation patterns.

    Directory of Open Access Journals (Sweden)

    Gerulf Rieger

    Full Text Available Recent research suggests profound sex and sexual orientation differences in sexual response. These results, however, are based on measures of genital arousal, which have potential limitations such as volunteer bias and differential measures for the sexes. The present study introduces a measure less affected by these limitations. We assessed the pupil dilation of 325 men and women of various sexual orientations to male and female erotic stimuli. Results supported hypotheses. In general, self-reported sexual orientation corresponded with pupil dilation to men and women. Among men, substantial dilation to both sexes was most common in bisexual-identified men. In contrast, among women, substantial dilation to both sexes was most common in heterosexual-identified women. Possible reasons for these differences are discussed. Because the measure of pupil dilation is less invasive than previous measures of sexual response, it allows for studying diverse age and cultural populations, usually not included in sexuality research.

  1. Postoperative follow-up studies in congenital dilatation of the common bile duct using hepatobiliary scintigraphy

    Energy Technology Data Exchange (ETDEWEB)

    Hirobe, Seiichi; Ishida, Haruo; Hayashi, Akira; Kamagata, Shoichiro; Fuchimoto, Yasufumi; Mizuno, Dai; Yano, Tsunehiro [Tokyo Metropolitan Kiyose Children`s Hospital (Japan); Ishii, Katsumi

    1995-03-01

    Follow-up studies in congenital dilatation of the common bile duct were done in 20 cases ranging 3 to 20 years after operation. Operative cholangiography had shown dilatation of the intrahepatic bile ducts in 15 patients (75%), of these, 7 patients had cystic dilatation. Five cases of these 7 patients showed prolonged stasis of the nuclide in the cystic dilated intrahepatic bile ducts by {sup 99m}Tc-PMT hepatobiliary scintigraphy in the follow-up studies even at 10 years after operation. But none of 20 cases had complication such as intrahepatic lithiasis, cholangitis, and liver dysfunction. Hepatobiliary scintigraphy could provide moderate anatomic and excellent functional information which were useful for these follow-up studies and careful follow-up should be done in the case of cystic dilatation of the intrahepatic bile ducts. (author).

  2. [Mechanical pupillary dilatation using rings in small pupils during cataract surgery : Video article].

    Science.gov (United States)

    Wirbelauer, C; Schmidt, S; Puk, C

    2018-03-22

    The purpose of mechanical pupillary dilatation in small pupils is a sufficient visualization of the lens to be able to perform capsulorhexis, phacoemulsification and intraocular lens implantation. The indications for mechanical dilatation are fulfilled in patients where a sufficient pharmacological preoperative pupil dilatation is not possible. During routine cataract surgery specific foldable rings can be employed to dilate the pupil with the appropriate injector under viscoelastic substances. These rings are carefully placed at the pupillary margin until circular pupillary dilatation up to 6-7 mm is achieved. After intraocular lens implantation and before removing the viscoelastic substance the rings are slowly folded into the injector and then removed. The surgical technique is demonstrated in detail with the help of a video of the operation, which is available online. Mechanical pupillary dilatation was possible in all patients studied (n = 14), which allowed uncomplicated phacoemulsification and intraocular lens implantation. For both ring systems studied the mean pupillary dilatation was 6.6 mm. At the end of surgery, the pupillary diameter was 4.89 mm using a Malyugin ring (MST, Redmond, Washington, USA) and 4.93 mm with an I‑ring (Visitec, Waltham, MA, USA; P > 0.05). Small lesions at the pupillary margin or pigment dispersion during implantation or explantation depended mostly on the individual patient situation and not on the ring used. Mechanical pupillary dilatation with rings allows sufficient dilatation to perform cataract surgery. Both the Malyugin ring and the I‑ring achieved smooth and atraumatic pupillary dilatation.

  3. Characterization, corrosion behavior, cellular response and in vivo bone tissue compatibility of titanium–niobium alloy with low Young's modulus

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Yanjie [Department of Oral and Maxillofacial Surgery, Laboratory of Interdisciplinary Studies, School and Hospital of Stomatology, Peking University, Beijing 100081 (China); Department of Stomatology, Aviation General Hospital of China Medical University and Beijing Institute of Translational Medicine, Chinese Academy of Science, Beijing 100012 (China); Deng, Yi [Department of Oral and Maxillofacial Surgery, Laboratory of Interdisciplinary Studies, School and Hospital of Stomatology, Peking University, Beijing 100081 (China); Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Zheng, Yunfei; Li, Yongliang [Department of Oral and Maxillofacial Surgery, Laboratory of Interdisciplinary Studies, School and Hospital of Stomatology, Peking University, Beijing 100081 (China); Zhang, Ranran; Lv, Yalin [Department of Stomatology, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029 (China); Zhao, Qiang, E-mail: 15911025865@139.com [Department of Stomatology, Aviation General Hospital of China Medical University and Beijing Institute of Translational Medicine, Chinese Academy of Science, Beijing 100012 (China); Wei, Shicheng, E-mail: sc-wei@pku.edu.cn [Department of Oral and Maxillofacial Surgery, Laboratory of Interdisciplinary Studies, School and Hospital of Stomatology, Peking University, Beijing 100081 (China); Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China)

    2016-02-01

    β-Type titanium alloys with a low elastic modulus are a potential strategy to enhance bone remodeling and to mitigate the concern over the risks of osteanabrosis and bone resorption caused by stress shielding, when used to substitute irreversibly impaired hard tissue. Hence, in this study, a Ti–45Nb alloy with low Young's modulus and high strength was developed, and microstructure, mechanical properties, corrosion behaviors, cytocompatibility and in vivo osteo-compatibility of the alloy were systematically investigated for the first time. The results of mechanical tests showed that Young's modulus of the Ti–Nb alloy was reduced to about 64.3 GPa (close to human cortical bone) accompanied with higher tensile strength and hardness compared with those of pure Ti. Importantly, the Ti–Nb alloy exhibited superior corrosion resistance to Ti in different solutions including SBF, MAS and FAAS (MAS containing NaF) media. In addition, the Ti–Nb alloy produced no deleterious effect to L929 and MG-63 cells, and cells performed excellent cell attachment onto Ti–Nb surface, indicating a good in vitro cytocompatibility. In vivo evaluations indicated that Ti–Nb had comparable bone tissue compatibility to Ti determined from micro-CT and histological evaluations. The Ti–Nb alloy with an elasticity close to human bone, thus, could be suitable for orthopedic/dental applications. - Highlights: • A β-type Ti–45Nb alloy was developed with low Young's modulus close to human bone. • Ti–Nb alloy had superior corrosion resistance to pure Ti in different solutions. • Ti–Nb alloy displayed good cytocompatibility and in vivo bone tissue compatibility. • Ti–Nb alloy could be suitable for orthopedic/dental application based on the study.

  4. Characterization, corrosion behavior, cellular response and in vivo bone tissue compatibility of titanium–niobium alloy with low Young's modulus

    International Nuclear Information System (INIS)

    Bai, Yanjie; Deng, Yi; Zheng, Yunfei; Li, Yongliang; Zhang, Ranran; Lv, Yalin; Zhao, Qiang; Wei, Shicheng

    2016-01-01

    β-Type titanium alloys with a low elastic modulus are a potential strategy to enhance bone remodeling and to mitigate the concern over the risks of osteanabrosis and bone resorption caused by stress shielding, when used to substitute irreversibly impaired hard tissue. Hence, in this study, a Ti–45Nb alloy with low Young's modulus and high strength was developed, and microstructure, mechanical properties, corrosion behaviors, cytocompatibility and in vivo osteo-compatibility of the alloy were systematically investigated for the first time. The results of mechanical tests showed that Young's modulus of the Ti–Nb alloy was reduced to about 64.3 GPa (close to human cortical bone) accompanied with higher tensile strength and hardness compared with those of pure Ti. Importantly, the Ti–Nb alloy exhibited superior corrosion resistance to Ti in different solutions including SBF, MAS and FAAS (MAS containing NaF) media. In addition, the Ti–Nb alloy produced no deleterious effect to L929 and MG-63 cells, and cells performed excellent cell attachment onto Ti–Nb surface, indicating a good in vitro cytocompatibility. In vivo evaluations indicated that Ti–Nb had comparable bone tissue compatibility to Ti determined from micro-CT and histological evaluations. The Ti–Nb alloy with an elasticity close to human bone, thus, could be suitable for orthopedic/dental applications. - Highlights: • A β-type Ti–45Nb alloy was developed with low Young's modulus close to human bone. • Ti–Nb alloy had superior corrosion resistance to pure Ti in different solutions. • Ti–Nb alloy displayed good cytocompatibility and in vivo bone tissue compatibility. • Ti–Nb alloy could be suitable for orthopedic/dental application based on the study.

  5. Small compression modulus of the flux line lattice and large density fluctuations at high fields may explain peak effect

    International Nuclear Information System (INIS)

    Brandt, E.H.

    1976-01-01

    The elastic properties of the flux line lattice in Type II superconductors as calculated from the Ginsburg-Landau theory are discussed. They are non-local on a length scale much larger than the flux line distance and divergent at Hsub(c2). The compression modulus may become much smaller than its long-wavelength limit, B 2 /4π, and if the deformation is not homogeneous, at Hsub(c2) the modulus vanishes as (Hsub(c2) - B) 2 . At arbitrary induction the compression modulus of strain waves with wavelengths of several flux line distances is of the order of the (small) shear modulus. (author)

  6. Anisotropic Young's Modulus for Single-Layer Black Phosphorus: The Third Principle Direction Besides Armchair and Zigzag

    OpenAIRE

    Jiang, Jin-Wu

    2015-01-01

    We derive an analytic formula for the Young's modulus in single-layer black phosphorus using the valence force field model. By analyzing the directional dependence for the Young's modulus, we explore the third principle direction with direction angle phi_tp = 0.268pi besides armchair and zigzag directions. The maximum Young's modulus value is in the third principle direction. More specifically, the Young's modulus is 52.2 N/m, 85.4 N/m, and 111.4 N/m in the armchair direction, zigzag directio...

  7. Granular Dilatancy and its Effect on Debris-flow Dynamics

    Science.gov (United States)

    Iverson, R. M.; George, D. L.

    2012-12-01

    Landslides and debris flows commonly exhibit the effects of variable granular dilatancy, but incorporation of these effects in predictive models of debris-flow dynamics has been lacking. We have developed a depth-averaged model of debris-flow initiation and motion that includes the effects of variable dilatancy without stipulating its influence on rheology. Instead, the apparent rheology of Coulomb-frictional debris evolves during coupled evolution of the grain concentration m, basal pore-fluid pressure, flow thickness, and flow velocity. The dilatancy angle ψ plays an intermediary role in this evolution and obeys the simple relationship tan ψ = m-meq, where meq is the grain concentration in equilibrium with the ambient stress state and flow rate. Results of recent stress-controlled rheometric experiments by Boyer et al. (DOI: 10.1103/PhysRevLett.107.188301) provide our basis for estimating meq. Relaxation of m toward meq, coupled with evolution of pore pressure, allows our model to simulate a smooth transition from static limiting equilibrium of slopes to disequilibrium flow dynamics. Use of variable friction coefficients or dam-break initial conditions is unnecessary. We have evaluated predictions of our model in three ways: (1) by examining physical implications of exact solutions of simplified model equations, (2) by comparing numerical solutions with results of controlled experiments at the USGS debris-flow flume, and (3) by comparing numerical predictions with the behavior of a large (~50 million m3) debris flow that occurred at Mt. Meager, British Columbia, in 2010. Model predictions depend mostly on initial conditions, flow-path topography, and the value of a single dimensionless parameter that represents the ratio of two key timescales. One timescale governs downslope, gravity-driven motion of debris, and the other governs pore-pressure diffusion. Values of these timescales are readily calculated from source-area geometry and standard geotechnical

  8. Determining Young's Modulus by Measuring Guitar String Frequency

    Science.gov (United States)

    Polak, Robert D.; Davenport, Adam R. V.; Fischer, Andrew; Rafferty, Jared

    2018-01-01

    Values for physical constants are commonly given as abstractions without building strong intuition, and are too often utilized solely in the pursuit of more easily conceptualized properties. The goal of this experiment is to remove the obscurity behind Young's modulus by exploring the phenomena associated with it--namely, the frequency of a…

  9. Effects of the temperature dependence of the bulk modulus on magnetic exchange-entropy

    International Nuclear Information System (INIS)

    Silva, J.A. da; Plaza, E.J.R.; Campoy, J.C.P.

    2015-01-01

    Highlights: • A thermodynamic route for the field-induced additional exchange-entropy was studied. • The temperature dependence of bulk modulus leads to the additional exchange-entropy. • The total entropy change matches with the sum of conventional and additional terms. • We obtained analytical expressions for deformation and additional exchange-entropy. - Abstract: We have studied the field-induced additional exchange-entropy on an elastic ferromagnet as a response effect of the dependence of its bulk modulus with temperature. We consider that the temperature dependence of the bulk modulus follows a linear behavior or a Wachtman-type equation. Our analysis is based on a free energy model containing exchange, Zeeman and elastic terms. From the deduced expressions for the exchange parameter, the additional exchange-entropy was obtained. This quantity must be the difference between the conventional and the total entropy change which were calculated from well-established thermodynamic expressions, i.e., configurational spin disorder and Maxwell’s equation, respectively. In addition, we established an analytical relation between the field-induced additional exchange-entropy and the temperature dependence of the bulk modulus

  10. Estimating Young’s Modulus of Single-Walled Zirconia Nanotubes Using Nonlinear Finite Element Modeling

    Directory of Open Access Journals (Sweden)

    Ibrahim Dauda Muhammad

    2015-01-01

    Full Text Available The single-walled zirconia nanotube is structurally modeled and its Young’s modulus is valued by using the finite element approach. The nanotube was assumed to be a frame-like structure with bonds between atoms regarded as beam elements. The properties of the beam required for input into the finite element analysis were computed by connecting energy equivalence between molecular and continuum mechanics. Simulation was conducted by applying axial tensile strain on one end of the nanotube while the other end was fixed and the corresponding reaction force recorded to compute Young’s modulus. It was found out that Young’s modulus of zirconia nanotubes is significantly affected by some geometrical parameters such as chirality, diameter, thickness, and length. The obtained values of Young’s modulus for a certain range of diameters are in agreement with what was obtained in the few experiments that have been conducted so far. This study was conducted on the cubic phase of zirconia having armchair and zigzag configuration. The optimal diameter and thickness were obtained, which will assist in designing and fabricating bulk nanostructured components containing zirconia nanotubes for various applications.

  11. The effect of heating rate and sintering temperature on the elastic modulus of porcelain tiles.

    Science.gov (United States)

    Eren Gültekin, Elif

    2018-02-01

    The scope of the present study is to investigate the change of elastic modulus with the physical and mechanical properties of porcelain tiles. In the study, porcelain tiles were sintered at different temperatures and at different heating rates to obtain minimum water absorption (%). After this, the time of flight of longitudinal and shear ultrasonic waves was measured through the tile. The time of flight of ultrasonic waves was measured using contact ultrasonic transducers operating on a pulse-echo mode. Using the time of flight of the ultrasonic waves and the thickness of the tiles, the velocity of the waves was determined. Using the ultrasonic velocities and bulk density, the elastic modulus of the tiles was determined. Helium pycnometry, a bend test, scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses were also carried out. The results show that the elastic modulus decreased with an increase of total porosity, but increased with bulk density and firing shrinkage. There is a polynomial relationship between elastic modulus and strength. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. The bulk modulus of cubic spinel selenides: an experimental and theoretical study

    DEFF Research Database (Denmark)

    Waskowska, A.; Gerward, Leif; Olsen, J.S.

    2009-01-01

    It is argued that mainly the selenium sublattice determines the overall compressibility of the cubic spinel selenides, AB2Se4, and that the bulk modulus for these compounds is about 100GPa. The hypothesis is supported by experiments using high-pressure X-ray diffraction and synchrotron radiation...

  13. Determining shear modulus of thin wood composite materials using a cantilever beam vibration method

    Science.gov (United States)

    Cheng Guan; Houjiang Zhang; John F. Hunt; Haicheng Yan

    2016-01-01

    Shear modulus (G) of thin wood composite materials is one of several important indicators that characterizes mechanical properties. However, there is not an easy method to obtain this value. This study presents the use of a newly developed cantilever beam free vibration test apparatus to detect in-plane G of thin wood composite...

  14. Effect of LED light-curing time for the adhesive resin on the modulus of elasticity.

    Science.gov (United States)

    Senawongse, Pisol; Harnirattisai, Choltacha; Otsuki, Masayuki; Tagami, Junji

    2007-06-01

    To evaluate the elastic modulus of successive layers where an adhesive resin was cured by different light-curing times. Eighty dentin discs which were 2 mm thick were prepared from 40 sound third molars. The dentin discs were further divided into four groups and bonded with 3M Single Bond 2 and cured with an LED for 5, 10, 15 and 20s. Bonded specimens were restored with a microhybrid resin composite. Specimens were cut perpendicular to the resin dentin interface, embedded in epoxy resin, and polished. Polished specimens were evaluated for the elastic modulus at the layer of dentin, hybrid layer, adhesive resin, and resin composite at 24 hours after preparation. Light-curing times influenced the elastic modulus of hybrid layer and adhesive resin. The significant differences of elastic modulus among successive layers were found. The results suggested that extension of light-curing times of adhesive resin from 5 to 20 seconds increased the mechanical properties of the resin dentin interface.

  15. Detail of photo 7903109 stack of superconducting cables in the modulus measuring device

    CERN Multimedia

    CERN PhotoLab

    1979-01-01

    The picture shows an assembly of insulated superconducting cables of the type used in the Po dipole magnet inserted in the elastic modulus measuring device (photos 7903547X and 7903169) in order to measures its mechanical properties under azimuthal compression. See also 7903547X, 7903169, 8307552X.

  16. The young's modulus of two phase and porous materials theory and experiment

    International Nuclear Information System (INIS)

    Nazare, S.; Ondracek, G.

    1977-01-01

    Theoretical methods to calculate the Young's modulus of two phase materials are discussed taking into account the concentration, shape and orientation of the phases. The results are simplified for the special case of porous materials and compared with experimental data. (author) [pt

  17. Effects of the temperature dependence of the bulk modulus on magnetic exchange-entropy

    Energy Technology Data Exchange (ETDEWEB)

    Silva, J.A. da [Departamento de Física, Universidade Federal de Sergipe, 49100-000 São Cristóvão, SE (Brazil); Plaza, E.J.R., E-mail: ejrplaza@gmail.com [Departamento de Física, Universidade Federal de Sergipe, 49100-000 São Cristóvão, SE (Brazil); Campoy, J.C.P. [Departamento de Ciências Naturais, Universidade Federal de São João del Rei, 36301-160 São João del Rei, MG (Brazil)

    2015-05-25

    Highlights: • A thermodynamic route for the field-induced additional exchange-entropy was studied. • The temperature dependence of bulk modulus leads to the additional exchange-entropy. • The total entropy change matches with the sum of conventional and additional terms. • We obtained analytical expressions for deformation and additional exchange-entropy. - Abstract: We have studied the field-induced additional exchange-entropy on an elastic ferromagnet as a response effect of the dependence of its bulk modulus with temperature. We consider that the temperature dependence of the bulk modulus follows a linear behavior or a Wachtman-type equation. Our analysis is based on a free energy model containing exchange, Zeeman and elastic terms. From the deduced expressions for the exchange parameter, the additional exchange-entropy was obtained. This quantity must be the difference between the conventional and the total entropy change which were calculated from well-established thermodynamic expressions, i.e., configurational spin disorder and Maxwell’s equation, respectively. In addition, we established an analytical relation between the field-induced additional exchange-entropy and the temperature dependence of the bulk modulus.

  18. Measurement of Elastic Modulus of Alumina and Barium Strontium Titanate Wafers Produced by Tape Casting Method

    Science.gov (United States)

    2014-02-01

    DATES COVERED (From – To) 4. TITLE AND SUBTITLE MEASUREMENT OF ELASTIC MODULUS OF ALUMINA AND BARIUM STRONTIUM TITANATE WAFERS PRODUCED BY...configuration testing method. Samples of barium strontium titanate (BST) were made using a regular powder pressing, sintering, pelletizing, and...fabricated using thin wafers of barium strontium titanate (BST) and aluminum oxide (alumina) ceramic during launch of a system. Sandia National

  19. Stiffness modulus and creep properties of the coconut shell in an ...

    African Journals Online (AJOL)

    Coconut shell (CS) is an agricultural waste engineered into a road construction material. This study was conducted to evaluate the stiffness modulus and dynamic creep properties of the asphaltic concrete containing CS as an aggregate replacement. A mixture design incorporating the bitumen penetration grade 60/70 was ...

  20. Modeling of nano-reinforced polymer composites: Microstructure effect on Young’s modulus

    DEFF Research Database (Denmark)

    Peng, R.D.; Zhou, H.W.; Wang, H.W.

    2012-01-01

    ” algorithm was developed in the ABAQUS Scripting Interface. In the computational studies, it was observed that the elastic modulus increases with the increasing the aspect ratio of nanoparticles. The thickness and properties of effective interface layers and the shape and degree of particles clustering have...

  1. Size-dependent effective Young’s modulus of silicon nitride cantilevers

    NARCIS (Netherlands)

    Babaei Gavan, K.; Westra, H.J.R.; Van der Drift, E.W.J.M.; Venstra, W.J.; Van der Zant, H.S.J.

    2009-01-01

    The effective Young’s modulus of silicon nitride cantilevers is determined for thicknesses in the range of 20–684 nm by measuring resonance frequencies from thermal noise spectra. A significant deviation from the bulk value is observed for cantilevers thinner than 150 nm. To explain the observations

  2. Determination of the Young's modulus of pulsed laser deposited epitaxial PZT thin films

    NARCIS (Netherlands)

    Nazeer, H.; Nguyen, Duc Minh; Woldering, L.A.; Abelmann, Leon; Rijnders, Augustinus J.H.M.; Elwenspoek, Michael Curt

    2011-01-01

    We determined the Young’s modulus of pulsed laser deposited epitaxially grown PbZr0.52Ti0.48O3 (PZT) thin films on microcantilevers by measuring the difference in cantilever resonance frequency before and after deposition. By carefully optimizing the accuracy of this technique, we were able to show

  3. Young's modulus and residual stress of GeSbTe phase-change thin films

    NARCIS (Netherlands)

    Nazeer, H.; Bhaskaran, Harish; Woldering, L.A.; Abelmann, Leon

    2015-01-01

    The mechanical properties of phase change materials alter when the phase is transformed. In this paper, we report on experiments that determine the change in crucial parameters such as Young's modulus and residual stress for two of the most widely employed compositions of phase change films,

  4. Dynamic characteristics of Bridgestone low shear modulus-high damping seismic isolation bearings

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Y.W.; Seidensticker, R.W.

    1993-06-01

    Bridgestone Company of Japan is one of the leading seismic bearing manufacturers in the world. Their bearings have very good performance records. It appears that Bridgestone`s high damping bearings are made of a blend of filled natural and synthetic rubbers with fillers and plastizers whereas in the United States, the high damping compound is a carbon filled natural rubber. To compare the properties of the two different kinds of high damping compounds, Argonne National Laboratory (ANL) purchased eight bearings from Bridgestone: four of which were made of high shear modulus-high damping rubber compound KL401; the other four were made of low shear modulus-high damping rubber compounds: two with KL301 elastomer and two with KL302 elastomer. Tests of the Bridgestone bearings were performed at the Earthquake Engineering Research Center. The dynamic characteristics of the high shear modulus Bridgestone bearings, KL401, are described in ANL/Shimizu Report ANL-003. This report describes the dynamic and failure characteristics of the low shear modulus Bridgestone bearings, KL301 and KL302.

  5. Noninvasive Vascular Displacement Estimation for Relative Elastic Modulus Reconstruction in Transversal Imaging Planes

    Directory of Open Access Journals (Sweden)

    Chris L. de Korte

    2013-03-01

    Full Text Available Atherosclerotic plaque rupture can initiate stroke or myocardial infarction. Lipid-rich plaques with thin fibrous caps have a higher risk to rupture than fibrotic plaques. Elastic moduli differ for lipid-rich and fibrous tissue and can be reconstructed using tissue displacements estimated from intravascular ultrasound radiofrequency (RF data acquisitions. This study investigated if modulus reconstruction is possible for noninvasive RF acquisitions of vessels in transverse imaging planes using an iterative 2D cross-correlation based displacement estimation algorithm. Furthermore, since it is known that displacements can be improved by compounding of displacements estimated at various beam steering angles, we compared the performance of the modulus reconstruction with and without compounding. For the comparison, simulated and experimental RF data were generated of various vessel-mimicking phantoms. Reconstruction errors were less than 10%, which seems adequate for distinguishing lipid-rich from fibrous tissue. Compounding outperformed single-angle reconstruction: the interquartile range of the reconstructed moduli for the various homogeneous phantom layers was approximately two times smaller. Additionally, the estimated lateral displacements were a factor of 2–3 better matched to the displacements corresponding to the reconstructed modulus distribution. Thus, noninvasive elastic modulus reconstruction is possible for transverse vessel cross sections using this cross-correlation method and is more accurate with compounding.

  6. High modulus asphalt (EME) technology transfer to South Africa and Australia: shared experiences

    CSIR Research Space (South Africa)

    Denneman, E

    2015-08-01

    Full Text Available The paper describes experiences with the implementation of French enrobés à module élevé (EME) (high modulus asphalt) technology in South Africa and Australia. Tentative performance specifications for EME mixes were set in the two countries based...

  7. Estimates of the integral modulus of continuity of functions with rarely changing Fourier coefficients

    International Nuclear Information System (INIS)

    Telyakovskii, S A

    2002-01-01

    The functions under consideration are those satisfying the condition Δa i =Δb i =0 for all i≠n j , where {n j } is a lacunary sequence. An asymptotic estimate of the rate of decrease of the modulus of continuity in the L-metric of such functions in terms of their Fourier coefficients is obtained

  8. Crystalline cellulose elastic modulus predicted by atomistic models of uniform deformation and nanoscale indentation

    Science.gov (United States)

    Xiawa Wu; Robert J. Moon; Ashlie Martini

    2013-01-01

    The elastic modulus of cellulose Iß in the axial and transverse directions was obtained from atomistic simulations using both the standard uniform deformation approach and a complementary approach based on nanoscale indentation. This allowed comparisons between the methods and closer connectivity to experimental measurement techniques. A reactive...

  9. Evaluation of Resilient Modulus of Subgrade and Base Materials in Indiana and Its Implementation in MEPDG

    Directory of Open Access Journals (Sweden)

    Richard Ji

    2014-01-01

    Full Text Available In order to implement MEPDG hierarchical inputs for unbound and subgrade soil, a database containing subgrade MR, index properties, standard proctor, and laboratory MR for 140 undisturbed roadbed soil samples from six different districts in Indiana was created. The MR data were categorized in accordance with the AASHTO soil classifications and divided into several groups. Based on each group, this study develops statistical analysis and evaluation datasets to validate these models. Stress-based regression models were evaluated using a statistical tool (analysis of variance (ANOVA and Z-test, and pertinent material constants (k1, k2 and k3 were determined for different soil types. The reasonably good correlations of material constants along with MR with routine soil properties were established. Furthermore, FWD tests were conducted on several Indiana highways in different seasons, and laboratory resilient modulus tests were performed on the subgrade soils that were collected from the falling weight deflectometer (FWD test sites. A comparison was made of the resilient moduli obtained from the laboratory resilient modulus tests with those from the FWD tests. Correlations between the laboratory resilient modulus and the FWD modulus were developed and are discussed in this paper.

  10. 2 filler on the dielectric permittivity and electrical modulus of PMMA

    Indian Academy of Sciences (India)

    The real and imaginary part of the dielectric permittivity decreased with the increase in frequency but increased with temperature. The electrical conductivity measurement showed a plateau-like behaviour in the low-frequency region and dispersion in the high-frequency region. The frequency-dependent electrical modulus ...

  11. Total energy, equation of state and bulk modulus of AlP, AlAs and ...

    Indian Academy of Sciences (India)

    Recently proposed model potential which combines both linear and quadratic types of interactions is employed for the investigation of some properties like the total energy, equation of state and bulk modulus of AlP, AlAs and AlSb semiconductor compounds using higher-order perturbation theory. The model potential ...

  12. Dynamic characteristics of Bridgestone low shear modulus-high damping seismic isolation bearings

    International Nuclear Information System (INIS)

    Chang, Y.W.; Seidensticker, R.W.

    1993-06-01

    Bridgestone Company of Japan is one of the leading seismic bearing manufacturers in the world. Their bearings have very good performance records. It appears that Bridgestone's high damping bearings are made of a blend of filled natural and synthetic rubbers with fillers and plastizers whereas in the United States, the high damping compound is a carbon filled natural rubber. To compare the properties of the two different kinds of high damping compounds, Argonne National Laboratory (ANL) purchased eight bearings from Bridgestone: four of which were made of high shear modulus-high damping rubber compound KL401; the other four were made of low shear modulus-high damping rubber compounds: two with KL301 elastomer and two with KL302 elastomer. Tests of the Bridgestone bearings were performed at the Earthquake Engineering Research Center. The dynamic characteristics of the high shear modulus Bridgestone bearings, KL401, are described in ANL/Shimizu Report ANL-003. This report describes the dynamic and failure characteristics of the low shear modulus Bridgestone bearings, KL301 and KL302

  13. Ultrasonic measurement of viscoelastic shear modulus development in hydrating cement paste.

    Science.gov (United States)

    Wang, Xiaojun; Subramaniam, Kolluru V; Lin, Fengbao

    2010-06-01

    A test procedure for measuring changes in amplitude and phase of SH ultrasonic waves from the interface between fused-quartz and cement paste samples is presented. The phase change is determined from the temporal shift in the reflected signal relative to the incident signal. The sensitivity of the measured parameters to changes in acoustic impedance of the materials in contact with fused-quartz is evaluated for different angles of incidence. It is shown that a reflection measurement at normal incidence at nano-second temporal resolution does not provide sufficient sensitivity to measure the viscous component of shear modulus of low viscosity fluids and cannot be applied to cement paste while it is in a fluid state. Monitoring the measured amplitude and phase at oblique angle of incidence allows for measuring fluids with acoustic impedance comparable to cement paste. The reflection measurements are used to determine the evolution of elastic and viscous components of shear modulus cement paste with time. Influence of sampling rate and temperature effects on the phase measurements are evaluated and shown to be significant. It is shown that the initial loss of workability of cement paste through setting process is associated with a larger relative increase in the viscous component of shear modulus. Following the initial rapid rise of the viscous component of shear modulus, there is a larger relative increase in the elastic component, which can be related to the emergence of a solid structure capable of retaining an imprint. 2010 Elsevier B.V. All rights reserved.

  14. Phenomenology of mixed modulus-anomaly mediation in fluxed string compactifications and brane models

    International Nuclear Information System (INIS)

    Choi, Kiwoon; Jeong, Kwang-Sik; Okumura, Ken-ichi

    2005-01-01

    In some string compactifications, for instance the recently proposed KKLT set-up, light moduli are stabilized by nonperturbative effects at supersymmetric AdS vacuum which is lifted to a dS vacuum by supersymmetry breaking uplifting potential. In such models, soft supersymmetry breaking terms are determined by a specific mixed modulus-anomaly mediation in which the two mediations typically give comparable contributions to soft parameters. Similar pattern of soft terms can arise also in brane models to stabilize the radion by nonperturbative effects. We examine some phenomenological consequences of this mixed modulus-anomaly mediation, including the pattern of low energy sparticle spectrum and the possibility of electroweak symmetry breaking. It is noted that adding the anomaly-mediated contributions at M GUT amounts to replacing the messenger scale of the modulus mediation by a mirage messenger scale (m 3/2 /M Pl ) α/2 M GUT where α = m 3/2 /[M 0 ln (M Pl /m 3/2 )] for M 0 denoting the modulus-mediated contribution to the gaugino mass at M GUT . The minimal KKLT set-up predicts α = 1. As a consequence, for α = O(1), the model can lead to a highly distinctive pattern of sparticle masses at TeV scale, particularly when α = 2

  15. The influence of resin flexural modulus on the magnitude of ceramic strengthening.

    LENUS (Irish Health Repository)

    Fleming, Garry J P

    2012-07-01

    The aim was to determine the magnitude of ceramic resin-strengthening with resin-based materials with varying flexural moduli using a regression technique to assess the theoretical strengthening at a \\'zero\\' resin-coating thickness. The hypothesis tested was that experimentally, increasing resin flexural modulus results in increased resin-strengthening observed at a theoretical \\'zero\\' resin-coating thickness.

  16. Cantilever-beam dynamic modulus for wood composite products. Part 1, apparatus

    Science.gov (United States)

    Chris Turk; John F. Hunt; David J. Marr

    2008-01-01

    A cantilever-beam vibration-testing apparatus has been developed to provide a means of dynamic and non-destructive evaluation of modulus of elasticity for small samples of wood or wood-composite material. The apparatus applies a known displacement to a cantilever beam and then releases the beam into its natural first-mode vibration and records displacement as a...

  17. Prediction of the elastic modulus of wood flour/kenaf fibre/polypropylene hybrid composites

    Science.gov (United States)

    Jamal Mirbagheri; Mehdi Tajvidi; Ismaeil Ghasemi; John C. Hermanson

    2007-01-01

    The prediction of the elastic modulus of short natural fibre hybrid composites has been investigated by using the properties of the pure composites through the rule of hybrid mixtures (RoHM) equation. In this equation, a hybrid natural fibre composite assumed as a system consisting of two separate single systems, namely particle/polymer and short-fibre/polymer systems...

  18. Elastic modulus in rigid Al{sub 2}O{sub 3}/ZrO{sub 2} ceramic laminates

    Energy Technology Data Exchange (ETDEWEB)

    Moya, J.S.; Sanchez-Herencia, J.A.; Bartolome, J.F. [CSIC, Madrid (Spain). Inst. de Ciencia de Materiales; Tanimoto, T. [Shonan Inst. of Tech., Fujisawa, Kanagawa (Japan)

    1997-10-01

    In previous works it has been shown that by making a three-layer composite in which the central region contains the matrix oxide and stabilized zirconia and the surface layers contain the matrix oxide and unstabilized zirconia, strength can be substantially enhanced relative to the monolithic materials containing the oxide matrix and either stabilized or unstabilized zirconia. The magnitude of the surface compressive stresses can be varied controlling the thickness of the outer layers and by proper thermal treatment in which the relative amounts of the monoclinic and tetragonal phases in the outer layers are controlled or by varying the volume fraction of total zirconia in the component. Often, the residual stresses are tailored to obtain high surface compression and a moderate bulk tension. In the present investigation, the authors have studied the effects of macroscopic residual stresses on stress intensities in the different layers of the Al{sub 2}O{sub 3}/ZrO{sub 2} laminates and the influence of the layered design on the elastic modulus of these materials.

  19. The clinical research office of the endourological society percutaneous nephrolithotomy global study: tract dilation comparisons in 5537 patients

    DEFF Research Database (Denmark)

    Lopes, Tomé; Sangam, Kandasami; Alken, Peter

    2011-01-01

    Abstract Purpose: The study focused on the use of balloon or telescopic/serial dilation methods in percutaneous nephrolithotomy (PCNL) in the Global PCNL Study. Patients and Methods: Centers worldwide provided data from consecutive patients who were treated with PCNL during a 1-year period. Tract...... eligible patients were entered in the database from November 2007 to December 2009, including 2277 (41.1%) who received balloon dilation and 3260 (58.9%) who received telescopic/serial dilation. The predominant method used was telescopic/serial dilation in Asia (94.7%) and South America (98...... telescopic/serial dilator group. Clavien scores II and IIIA were slightly in favor of the telescopic/serial dilator group. Median operative time was longer in the balloon dilation group (94.0 min vs 60.0 min). Conclusions: The Global PCNL Study has identified differences in the method of dilation used...

  20. Effect of bulk modulus on deformation of the brain under rotational accelerations

    Science.gov (United States)

    Ganpule, S.; Daphalapurkar, N. P.; Cetingul, M. P.; Ramesh, K. T.

    2018-01-01

    Traumatic brain injury such as that developed as a consequence of blast is a complex injury with a broad range of symptoms and disabilities. Computational models of brain biomechanics hold promise for illuminating the mechanics of traumatic brain injury and for developing preventive devices. However, reliable material parameters are needed for models to be predictive. Unfortunately, the properties of human brain tissue are difficult to measure, and the bulk modulus of brain tissue in particular is not well characterized. Thus, a wide range of bulk modulus values are used in computational models of brain biomechanics, spanning up to three orders of magnitude in the differences between values. However, the sensitivity of these variations on computational predictions is not known. In this work, we study the sensitivity of a 3D computational human head model to various bulk modulus values. A subject-specific human head model was constructed from T1-weighted MRI images at 2-mm3 voxel resolution. Diffusion tensor imaging provided data on spatial distribution and orientation of axonal fiber bundles for modeling white matter anisotropy. Non-injurious, full-field brain deformations in a human volunteer were used to assess the simulated predictions. The comparison suggests that a bulk modulus value on the order of GPa gives the best agreement with experimentally measured in vivo deformations in the human brain. Further, simulations of injurious loading suggest that bulk modulus values on the order of GPa provide the closest match with the clinical findings in terms of predicated injured regions and extent of injury.

  1. Development of a new β Ti alloy with low modulus and favorable plasticity for implant material

    Energy Technology Data Exchange (ETDEWEB)

    Liang, S.X., E-mail: liangshx@hebeu.edu.cn [College of Equipment Manufacture, Hebei University of Engineering, Handan 056038, Hebei (China); Feng, X.J.; Yin, L.X.; Liu, X.Y. [College of Equipment Manufacture, Hebei University of Engineering, Handan 056038, Hebei (China); Ma, M.Z., E-mail: mz550509@ysu.edu.cn [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Liu, R.P. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China)

    2016-04-01

    One of the most important development directions of the Ti and its alloys is the applications in medical field. Development of new Ti alloys with low elastic modulus and/or favorable biocompatibility plays an important role for promoting its application in medical field. In this work, a new β Ti alloy (Ti–31Nb–6Zr–5Mo, wt.%) was designed for implant material using d-electron alloy design method. Microstructure and tensile properties of the designed alloy after hot rolling (HR) and solution followed by aging treatments (SA) were investigated. Results show that the designed alloy is composed of single β phase. However, microstructural analysis shows that the β phase in the designed alloy separates into Nb-rich and Nb-poor phase regions. The Nb-rich regions in HR specimen are typical elongated fiber texture, but are equiaxed particles with several micrometers in SA specimen. Tensile results show that the designed alloy has low Young's modulus of 44 GPa for HR specimen and 48 GPa for SA specimen which are very close to the extreme of Young's modulus of bulk titanium alloys. At the same time, the designed alloy has favorable plasticity in term of elongation of 26.7% for HR specimen and 20.6% for SA specimen, and appropriate tensile strength over 700 MPa. In short, the designed alloy has low elastic modulus close to that of bone and favorable plasticity and strength which can be a potential candidate for hard tissue replacements. - Highlights: • A new Ti alloy was designed and prepared using electron alloy design method. • The alloy has low elastic modulus of 44 GPa, favorable plasticity and strength. • The new designed Ti alloy is fully composed of β phase. • Phase separation occurs in the new designed Ti alloy.

  2. On the theory of time dilation in chemical kinetics

    Science.gov (United States)

    Baig, Mirza Wasif

    2017-10-01

    The rates of chemical reactions are not absolute but their magnitude depends upon the relative speeds of the moving observers. This has been proved by unifying basic theories of chemical kinetics, which are transition state theory, collision theory, RRKM and Marcus theory, with the special theory of relativity. Boltzmann constant and energy spacing between permitted quantum levels of molecules are quantum mechanically proved to be Lorentz variant. The relativistic statistical thermodynamics has been developed to explain quasi-equilibrium existing between reactants and activated complex. The newly formulated Lorentz transformation of the rate constant from Arrhenius equation, of the collision frequency and of the Eyring and Marcus equations renders the rate of reaction to be Lorentz variant. For a moving observer moving at fractions of the speed of light along the reaction coordinate, the transition state possess less kinetic energy to sweep translation over it. This results in the slower transformation of reactants into products and in a stretched time frame for the chemical reaction to complete. Lorentz transformation of the half-life equation explains time dilation of the half-life period of chemical reactions and proves special theory of relativity and presents theory in accord with each other. To demonstrate the effectiveness of the present theory, the enzymatic reaction of methylamine dehydrogenase and radioactive disintegration of Astatine into Bismuth are considered as numerical examples.

  3. Comparison of Complications in Percutaneous Dilatational Tracheostomy versus Surgical Tracheostomy

    Science.gov (United States)

    Yaghoobi, Siamak; Kayalha, Hamid; Ghafouri, Raziyeh; Yazdi, Zohreh; Khezri, Marzieh Beigom

    2014-01-01

    Background: Tracheostomy facilitates respiratory care and the process of weaning from mechanical ventilatory support. Aims: To compare the complications found in percutaneous dilatational tracheostomy (PDT) and surgical tracheostomy (ST) techniques. Methods: This was a prospective randomized study to evaluate the complications of PDT and ST procedures in patients admitted to ICU unit of a teaching hospital during 2008 to 2011. We studied 40 patients in each group. PDTs were performed with blue rhino technique at the bedside by a skilled clinician and all cases of STs performed by Charles G Durbin technique in operating room under general anesthesia. Bronchoscopic examination through tracheostomy tube was performed to ensure the correct position of tracheostomy tube in the trachea lumen. The duration of procedures and pre- and post-interventional complications were recorded. Results: The most common complications observed in the PDT group were minor bleeding (n=4), hypoxemia, and cardiac dysrhythmias (n=3) whereas in the ST group, the most frequent complications were minor bleeding (n=5) and endotracheal tube puncture (n=3). The difference in overall complications between the two groups was insignificant (P=0.12). Conclusion: PDT with blue rhino technique is a safe, quick, and effective method while the overall complications in both groups were comparable. PMID:24999127

  4. Hemoperitoneum secondary to cecocolic dilation in a pregnant mare

    Directory of Open Access Journals (Sweden)

    Alejandro R. Palomar

    2017-06-01

    Full Text Available Hemoperitoneum is known as the abnormal accumulation of blood within the abdominal cavity, most commonly caused by gastrointestinal bleeding, abdominal abscesses, liver tumors, migration of parasitic larvae (Strongylus vulgaris, direct trauma and blood clotting disorders. Lethargy, anorexia, weakness, muscle twitching, sweating, hyperthermia, tachycardia, tachypnea, and the accumulation of free fluid in the abdomen were the most commonly recorded signs. In this report, a pregnant mare was diagnosed with hemoperitoneum secondary to cecocolic dilatation, due to corn ingestion. The protocol for clinical treatment and tests varies in similar reported cases. Due to this, the present report discusses the outcome of a clinical case and suggests a medical protocol -based on evidence – for treatment in a pregnant mare. The treatment was aimed to stop the bleeding, while normalize or maintain a stable blood pressure and provide supportive therapy. The mare presented colic pains due to fermentation of the corn, which were solved in few hours. The final abdominal ultrasonogram showed intra-abdominal hypoechoic fluid and living fetus.

  5. Clinical predictors of outcome in patients with inflammatory dilated cardiomyopathy.

    Directory of Open Access Journals (Sweden)

    Konstantinos Karatolios

    Full Text Available The study objectives were to identify predictors of outcome in patients with inflammatory dilated cardiomyopathy (DCMi.From 2004 to 2008, 55 patients with biopsy-proven DCMi were identified and followed up for 58.2±19.8 months. Predictors of outcome were identified in a multivariable analysis with a Cox proportional hazards analysis. The primary endpoint was a composite of death, heart transplantation and hospitalization for heart failure or ventricular arrhythmias.For the primary endpoint, a QTc interval >440msec (HR 2.84; 95% CI 1.03-7.87; p = 0.044, a glomerular filtration rate (GFR 440msec, a GFR<60ml/min/1.73m2 and worsening of NYHA classification during follow-up were univariate predictors of adverse prognosis. In contrast, NYHA classification at baseline, left ventricular ejection fraction, atrial fibrillation, treatment with digitalis or viral genome detection were not related to outcome. After multivariable analysis, a GFR <60ml/min/1.73m2 remained independently associated with adverse outcome.

  6. [Diagnosis and management of urinary tract dilatations detected in utero].

    Science.gov (United States)

    Martini, Stephan; Guignard, Jean-Pierre

    2002-12-01

    About 1% of the newborns show abnormalities of the urinary tract, representing 25% of the antenatally detected malformations. Most of these urinary abnormalities are detected by prenatal ultrasound between the 14th and the 22nd week of gestation. Their outcome is determined during the first weeks of pregnancy and depends on the degree of renal impairment and the presence of associated extrarenal malformations. Establishing the outcome is often difficult, however it can be predicted by ultrasound and biochemistry of fetal urine. Prenatal management should consist in follow-up and careful organisation of the postnatal management of congenital uropathies. Every antenatally dilated urinary tract requires postnatal investigation. Postnatal ultrasound on the 3rd to 4th day of life is recommended for confirming or excluding urinary abnormalities. In case of persistence, ultrasound has to be completed by other radiologic methods. Voiding cystourethrography and/or nuclear renography allow to identify the origin of the observed abnormalities. Apart from a few situations needing immediate correction, surgical treatment is rarely indicated. The principal of postnatal management is prevention of urinary tract infections by antibiotic prophylaxis and a close follow-up until adulthood.

  7. Current status of endoscopic balloon dilation for Crohn's disease

    Directory of Open Access Journals (Sweden)

    Fumihito Hirai

    2017-04-01

    Full Text Available The therapeutic target in Crohn's disease (CD has been raised to the achievement of mucosal healing. Although effective treatments that target cytokines and other molecules has been widely used for CD, intestinal strictures are still a major cause of surgery. Endoscopic balloon dilation (EBD is known to be an effective and safe intervention for intestinal strictures in CD. Since frequent intestinal resection often results in short bowel syndrome and can decrease the quality of life, EBD can help avoid surgery. EBD with a conventional colonoscope for Crohn's strictures of the colon and ileo-colonic anastomosis has established efficacy and safety. In addition, EBD using balloon-assisted enteroscopy has recently been applied for small bowel Crohn's strictures. Although the evidence is not strong, EBD may become an alternative to surgery in small bowel strictures in CD. EBD and other new methods such as self-expanding stent implantation for Crohn's strictures may be useful and safe; however, it is important to address several issues regarding these interventions and to establish a protocol for combined therapies.

  8. Oxidative Stress in Dilated Cardiomyopathy Caused by MYBPC3 Mutation

    Directory of Open Access Journals (Sweden)

    Thomas L. Lynch

    2015-01-01

    Full Text Available Cardiomyopathies can result from mutations in genes encoding sarcomere proteins including MYBPC3, which encodes cardiac myosin binding protein-C (cMyBP-C. However, whether oxidative stress is augmented due to contractile dysfunction and cardiomyocyte damage in MYBPC3-mutated cardiomyopathies has not been elucidated. To determine whether oxidative stress markers were elevated in MYBPC3-mutated cardiomyopathies, a previously characterized 3-month-old mouse model of dilated cardiomyopathy (DCM expressing a homozygous MYBPC3 mutation (cMyBP-C(t/t was used, compared to wild-type (WT mice. Echocardiography confirmed decreased percentage of fractional shortening in DCM versus WT hearts. Histopathological analysis indicated a significant increase in myocardial disarray and fibrosis while the second harmonic generation imaging revealed disorganized sarcomeric structure and myocyte damage in DCM hearts when compared to WT hearts. Intriguingly, DCM mouse heart homogenates had decreased glutathione (GSH/GSSG ratio and increased protein carbonyl and lipid malondialdehyde content compared to WT heart homogenates, consistent with elevated oxidative stress. Importantly, a similar result was observed in human cardiomyopathy heart homogenate samples. These results were further supported by reduced signals for mitochondrial semiquinone radicals and Fe-S clusters in DCM mouse hearts measured using electron paramagnetic resonance spectroscopy. In conclusion, we demonstrate elevated oxidative stress in MYPBC3-mutated DCM mice, which may exacerbate the development of heart failure.

  9. Right ventricular function in patients with dilated cardiomyopathy

    International Nuclear Information System (INIS)

    Kubota, Shuhei; Kubota, Sachio; Iwase, Takashi; Iizuka, Toshio; Imai, Susumu; Murata, Kazuhiko; Inoue, Tomio; Suzuki, Tadashi; Sasaki, Yasuhito.

    1993-01-01

    The characteristics and pathogenesis of right ventricular dysfunction in 14 patients with dilated cardiomyopathy (DCM) were investigated by equilibrium right ventricular blood pool scintigraphy using ultrashort-lifetime 81m Kr. Thirteen patients with severe left ventricular dysfunction due to old anterior myocardial infarction (OMI) and nine normal subjects were used as controls. The right ventricular end-diastolic pressure and volume index, mean pulmonary arterial pressure, and total pulmonary vascular resistance index were almost the same in the DCM and OMI patients. The right ventricular ejection fraction was 44.2±6.0% (mean±SD) in DCM patients and 47.1±7.9% in OMI patients, both significantly lower than those in the normal subjects (54.5±5.3%), but with no difference between the two case groups. The right ventricular peak filling rate was significantly reduced in both case groups as compared with the normal subjects (2.46±0.81 EDV/sec). The reduction was significantly greater (p 81m Kr blood pool scintigraphy is useful in the study of the right ventricular systolic and diastolic function. The diastolic parameters are more sensitive indicators for evaluation of right ventricular function in DCM than the systolic parameters. (author)

  10. Synthetic Pulse Dilation - PMT Model for high bandwidth gamma measurements

    Science.gov (United States)

    Geppert-Kleinrath, H.; Herrmann, H. W.; Kim, Y. H.; Zylstra, A. B.; Meaney, K. D.; Lopez, F. E.; Khater, H.; Horsfield, C. J.; Gales, S.; Leatherland, A.; Hilsabeck, T.; Kilkenny, J. D.; Hares, J. D.; Dymoke-Bradshaw, T.; Milnes, J.

    2017-10-01

    The Cherenkov mechanism used in Gas Cherenkov Detectors (GCD) is exceptionally fast. However, the temporal resolution of GCDs, such as the Gamma Reaction History diagnostic (GRH), is limited by the current state-of-the-art photomultiplier tube (PMT) to 100 ps. The new pulse dilation - PMT (PD-PMT) for NIF allows for a temporal resolution comparable to that of the gas cell, or of 10ps. Enhanced resolution will contribute to the quest for ignition in a crucial way through precision measurement of reaction history and areal density (ρ R) history, leading to better constrained models. Features such as onset of alpha heating, shock reverberations and burn truncation due to dynamically evolving failure modes will become visible for the first time. PD-PMT will be deployed on GCD-3 at NIF in 2018. Our synthetic PD-PMT model evaluates the capabilities of these future measurements, as well as minimum yield requirements for measurements performed in a well at 3.9 m from target chamber center (TCC), and within a diagnostic inserter at 0.2m from TCC.

  11. Diuretic renography in evaluating dilated upper urinary tract in children

    International Nuclear Information System (INIS)

    Ireton, R.C.; Parker, R.M.; Hayden, P.

    1987-01-01

    The diuretic renogram provides a previously unavailable noninvasive method for assessing and following urinary tract dilation of diverse cause, and defining true obstruction in children. Technetium-99m-DTPA (diethylenetriaminepentaacetic acid) is injected intravenously and a posteriorly placed gamma scintillation camera used to image the kidneys, ureters, and bladder. Furosemide is subsequently injected to stimulate a diuresis, and the washout pattern of isotope is monitored (time-activity histogram). Nonobstructive, obstructive, and poor renal function patterns were seen. Forty patients with varying degrees of hydroureteronephrosis were evaluated. Tracings were performed serially and compared with the clinical course in time, as well as with pressure flow studies and operative findings. All patients with a nonobstructed diuretic renogram did well, except for 1 boy in whom ureteropelvic obstruction developed later. Difficulty in evaluating the obstructive renogram pattern occurred only in some children with severe (grade V) hydronephrosis. Further standardization of the diuretic renogram with regard to time of diuretic injection, state of patient hydration, and regions of imaging may improve diagnostic accuracy

  12. Balloon Dilatation of Pediatric Subglottic Laryngeal Stenosis during the Artificial Apneic Pause: Experience in 5 Children

    Directory of Open Access Journals (Sweden)

    J. Lisý

    2014-01-01

    Full Text Available Introduction. Balloon dilatation is a method of choice for treatment of laryngeal stenosis in children. The aim of procedure in apneic pause is to avoid new insertion of tracheostomy cannula. Patients and Methods. The authors performed balloon dilatation of subglottic laryngeal strictures (SGS in 5 children (3 girls and 2 boys without tracheotomy. Two of them with traumatic and inflammatory SGS had a tracheal cannula removed in the past. The other 3 children with postintubation SGS had never had a tracheostomy before. The need for tracheostomy due to worsening stridor was imminent for all of them. Results. The total of seven laryngeal dilatations by balloon esophagoplasty catheter in apneic pause was performed in the 5 children. The procedure averted the need for tracheostomy placement in 4 of them (80%. Failure of dilatation in girl with traumatic stenosis and concomitant severe obstructive lung disease led to repeated tracheostomy. Conclusion. Balloon dilatation of laryngeal stricture could be done in the absence of tracheostomy in apneic pause. Dilatation averted threatening tracheostomy in all except one case. Early complication after the procedure seems to be a negative prognostic factor for the outcome of balloon dilatation.

  13. Diagnostic value to depict branch pancreatic ducts dilatation by MR cholangiopancreatography

    International Nuclear Information System (INIS)

    Li Liang; Yuan Jiachang; Jin Erhu

    2009-01-01

    Objective: To evaluate the diagnostic value of depicting dilatation of branch pancreatic ducts (BPD) in patients with chronic pancreatitis and pancreatic carcinomas in MR cholangiopancreatography. Methods: Forty-five patients with chronic pancreatitis and thirty patients with pancreatic carcinomas were enrolled in the study. All the patients underwent MRI using axial T 1 weighted imaging, T 2 weighted imaging and MR cholangiopancreatography in a 3.0 T MR unit. and dilatation of BPD was analyse by which their morphology, location and extent of dilatation. Results: Morphologically, dilatation of BPD in cystic, dendroid manner or both of them were seen in 19, 42 and 16 cases in chronic pancreatitis, and 6, 29 and 5 cases in pancreatic carcinomas, respectively. In location, dilatation of BPD in proximal, distal or full coverage of main pancreatic duct were seen in 0, 10 and 35 cases in chronic pancreatitis, and 1, 12 and 17 cases in pancreatic carcinomas, respectively. Conclusion: Dilatation of BPD and main pancreatic duct could be well visualized in MR cholangiopancreatography at 3.0 T. It is helpful in differentiating chronic pancreatitis and pancreatic cancinoma to be familiar with features of dilatation of BPD. (authors)

  14. Trans-Balloon Visualisation During Dilatation (TBVD) of Oesophageal Strictures: a Novel Innovation.

    Science.gov (United States)

    Khokhar, Haseeb A; Azeem, Beenish; Bughio, Mumtaz; Bass, Gary A; Elfadul, Amr; Salih, Monim; Fahmy, Waleed; Walsh, Thomas N

    2016-04-01

    Hydrostatic balloon dilatation of upper gastrointestinal strictures is associated with a risk of perforation that varies with the underlying pathology and with the technique employed. We present a technique of trans-balloon visualisation of the stricture during dilatation (TBVD) that allows direct 'real-time' observation of the effect of dilatation on the stricture, facilitating early recognition of mucosal abruption, thereby reducing the perforation rate. We retrospectively analysed 100 consecutive patients, undergoing balloon dilatation of oesophageal strictures between 1st of January 2011 and 1st of July 2014. One hundred patients underwent 186 dilatations, with 34 having multiple procedures (mean 1.86). All had oesophageal strictures (mean diameter 8.49 mm, range 5-11 mm) and most underwent dilatation up to a maximum of 17 mm (mean 14.7 mm). Fifty-six percent were male and the average age was 62.5 years (17-89 years). Only one patient (0.5% of all procedures) had a full-thickness perforation requiring intervention while just one further patient had a deep mucosal tear that did not require intervention. TBVD is a safe technique with a short learning curve and is one of the important factors that allow potentially difficult dilatations to be performed safely with an exceptionally low rate of adverse events of less than 1%.

  15. The use of endoscopic ultrasonography in the diagnosis of the causes of common bile duct dilation

    International Nuclear Information System (INIS)

    Sajewicz, Z.; Wozniak-Stolarska, B.; Salomon, A.; Poniewierka, E.; Kempinski, R.

    2006-01-01

    Background. Ultrasonography (US) does not come up to the expectations in the diagnosis of the causes of common bile duct (CBD) dilation. Objectives. An assessment of the usefulness of endoscopic ultrasonography (EUS) in the diagnosis of the causes of CBD dilation. Material and Methods. The authors examined 30 persons (16 females and 14 males) with CBD dilated > 7 mm in US. In these patients the authors performed EUS with the usage of Pentax FG-38UX echoendoscope of 5-10 MHz frequency connected with EUB 6000 Hitachi ultrasonograph looking for the cause of CBD dilation. Findings gathered were verified with the usage of endoscopic retrograde cholangiopancreatography (ERCP) or magnetic resonance cholangiopancreatography (MRCP). Results. In 16 patients the authors found stones in CBD. In ERCP or MRCP the frequency of CBD stones was a bit higher. In these examinations CBD stones were found in 18 patients. The authors found out that pancreatic head carcinoma was the cause of CBD dilation in 8 patients; in 2 patients the authors diagnosed ampullary carcinoma and in 1 patient - carcinoma of distal part of CBD. In 1 patient the authors pointed out a benign stricture of CBD with dilation above the stricture. Conclusions. EUS is a useful diagnosing method of the causes of CBD dilation. (authors)

  16. Cervical dilation before first-trimester surgical abortion (<14 weeks' gestation).

    Science.gov (United States)

    Allen, Rebecca H; Goldberg, Alisa B

    2016-04-01

    First-trimester surgical abortion is a common, safe procedure with a major complication rate of less than 1%. Cervical dilation before suction abortion is usually accomplished using tapered mechanical dilators. Risk factors for major complications in the first trimester include increasing gestational age and provider inexperience. Cervical priming before first-trimester surgical abortion has been studied using osmotic dilators and pharmacologic agents, most commonly misoprostol. Extensive data demonstrate that a variety of agents are safe and effective at causing preoperative cervical softening and dilation; however, given the small absolute risk of complications, the benefit of routine use of misoprostol or osmotic dilators in first-trimester surgical abortion is unclear. Although cervical priming results in reduced abortion time and improved provider ease, it requires a delay of at least 1 to 3 h and may confer side effects. The Society of Family Planning does not recommend routine cervical priming for first-trimester suction abortion but recommends limiting consideration of cervical priming for women at increased risk of complications from cervical dilation, including those late in the first trimester, adolescents and women in whom cervical dilation is expected to be challenging. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Intracervical versus vaginal misoprostol for cervical dilatation prior to operative hysteroscopy—a comparative study

    Science.gov (United States)

    Goyal, BK; Roy, Premansu; Bhat, PM; Das, NK; Paul, KG; Duggal, BS

    2012-01-01

    Background Hysteroscopic surgery requires pre-operative cervical ripening to facilitate adequate dilatation of the cervix for insertion of operative hysteroscope. This study was conducted to compare the efficacy of intracervical misoprostol with vaginal misoprostol in achieving cervical ripening before operative hysteroscopy. Methods In this randomised comparative study conducted at a tertiary care teaching hospital, 56 patients needing operative hysteroscopy were divided into two groups of 28 patients, one for intracervical misoprostol and the other for vaginal misoprostol. Four hundred microgram of misoprostol was inserted on the night before and in the morning of operative hysteroscopy intracervically in group I and vaginally in group II. Results Primary outcome measure was number of patients achieving 7 mm preoperative dilatation of cervix. Largest Hegar dilator that could be passed into the uterine cavity past the internal optic sheath without resistance was noted in each case. Mean cervical dilatation prior to operative hysteroscopy was calculated. In addition, incidence of slipping of vulsellum and cervical laceration was also noted. Time to achieve full cervical dilatation was recorded. In 23/28 cases of group I and 5/28 in group II, size 7 Hegar dilator could be passed without effort. Mean cervical dilatation was 7.5 mm in group I and 5.7 mm in group II. Slipping of the vulsellum and cervical lacerations were seen in significantly less patients in group I. Mean time to achieve cervical dilatation to 10 mm was 43.39 seconds in group I and 103.96 seconds in group II (PIntracervical administration of misoprostol is an effective method of achieving cervical ripening for easy cervical dilatation up to 10 mm prior to operative hysteroscopy. PMID:24669051

  18. Intracervical versus vaginal misoprostol for cervical dilatation prior to operative hysteroscopy-a comparative study.

    Science.gov (United States)

    Goyal, Bk; Roy, Premansu; Bhat, Pm; Das, Nk; Paul, Kg; Duggal, Bs

    2012-04-01

    Hysteroscopic surgery requires pre-operative cervical ripening to facilitate adequate dilatation of the cervix for insertion of operative hysteroscope. This study was conducted to compare the efficacy of intracervical misoprostol with vaginal misoprostol in achieving cervical ripening before operative hysteroscopy. In this randomised comparative study conducted at a tertiary care teaching hospital, 56 patients needing operative hysteroscopy were divided into two groups of 28 patients, one for intracervical misoprostol and the other for vaginal misoprostol. Four hundred microgram of misoprostol was inserted on the night before and in the morning of operative hysteroscopy intracervically in group I and vaginally in group II. Primary outcome measure was number of patients achieving 7 mm preoperative dilatation of cervix. Largest Hegar dilator that could be passed into the uterine cavity past the internal optic sheath without resistance was noted in each case. Mean cervical dilatation prior to operative hysteroscopy was calculated. In addition, incidence of slipping of vulsellum and cervical laceration was also noted. Time to achieve full cervical dilatation was recorded. In 23/28 cases of group I and 5/28 in group II, size 7 Hegar dilator could be passed without effort. Mean cervical dilatation was 7.5 mm in group I and 5.7 mm in group II. Slipping of the vulsellum and cervical lacerations were seen in significantly less patients in group I. Mean time to achieve cervical dilatation to 10 mm was 43.39 seconds in group I and 103.96 seconds in group II (PIntracervical administration of misoprostol is an effective method of achieving cervical ripening for easy cervical dilatation up to 10 mm prior to operative hysteroscopy.

  19. Comparison of Dilation Methods in Percutaneous Nephrolithotomy: Which One Is More Successful?

    Science.gov (United States)

    Nalbant, Ismail; Karakoyunlu, Ahmet Nihat; Yesil, Suleyman; Ekici, Musa; Zengin, Kursad; Ozturk, Ufuk; Imamoğlu, Muhammed Abdurrahim

    2016-06-01

    Creation of the access tract is an important step in percutaneous nephrolithotomy (PNL). In this study, we compared the efficiency and safety of Amplatz, Alken, and balloon dilation methods in the creation of the access tract. Data from 487 PNL patients admitted to 517 renal units in 3 centers were analyzed. The Amplatz (280 patients), Alken (142 patients), and balloon (95 patients) dilation methods were compared for their success, duration of the dilation, injury to the collecting system, durations of fluoroscopy and surgery, stone-free and complication rates, pre- and postoperative hematocrit levels, and need for blood transfusion. The dilation methods did not significantly differ with respect to patient demographic data, mean stone area, decrease in hematocrit, need for blood transfusion, unsuccessful tract dilation, injury to the collecting system, stone-free rate, and rate of postoperative complications. The mean fluoroscopy times during Amplatz, Alken, and balloon dilation were 288.52 ± 164.67, 287.34 ± 164.99, and 169.23 ± 21 seconds, respectively. The mean duration of surgery was 96.48 ± 46.07, 94.72 ± 42.25, and 78 ± 25.96 minutes, respectively. The duration of tract creation was 328.67 ± 172.99, 325.14 ± 175.70, and 203.50 ± 32.76 seconds, respectively. The durations of surgery and tract creation were significantly shorter in the balloon dilation group. None of the dilation methods was significantly superior in terms of surgical success, efficiency, or safety. Although balloon dilation was advantageous with respect to time parameters, the role of surgical experience should not be ignored.

  20. Quadricuspid Aortic Valve Combined with Moderate Ascending Aortic Dilatation: A Report of Four Cases.

    Science.gov (United States)

    Uspenskiy, Vladimir E; Osadchii, Alexei M; Gordeev, Mikhail L

    2015-12-01

    The quadricuspid aortic valve is a very uncommon malformation associated with aortic insufficiency, aortic stenosis, endocarditis, and ascending aortic dilatation. We report four cases of this aortic valve malformation. One patient with severe aortic regurgitation and moderate aortic dilatation required aortic valve replacement. Three patients had mild or moderate aortic insufficiency combined with moderate ascending aortic dilatation. These patients were referred to follow-up. The presented cases demonstrate that this aortic valve malformation may not be as rare as it appears and that attention must be paid to any quadricuspid findings during computed tomographic angiography and echocardiography.

  1. [Successful endoscopic dilatation of a stenosis in relation to an ileorectal anastomosis by acute ileus].

    Science.gov (United States)

    Kjærgaard, Jane Christensen; Hendel, Jakob; Gügenur, Ismail

    2014-02-17

    Endoscopic dilatation is a treatment option for patients with Crohns disease suffering from stenosis in relation to an ileorectal anastomosis. We present a case of a patient with Crohns disease who was admitted with acute obstructive symptoms due to a stensosis of the ileorectal anastomosis. The patient was septic. We performed a successful endoscopic dilatation in the acute phase and the patient was discharged few days after an uneventful recovery. Endoscopic dilatation of an ileorectal anastomsis in patients with Crohns disease is a treatment option in the acute setting when performed by experienced endoscopists.

  2. Calculation of wear (f.i. wear modulus) in the plastic cup of a hip joint prosthesis

    NARCIS (Netherlands)

    Ligterink, D.J.

    1975-01-01

    The wear equation is applied to the wear process in a hip joint prosthesis and a wear modulus is defined. The sliding distance, wear modulus, wear volume, wear area, contact angle and the maximum normal stress were calculated and the theoretical calculations applied to test results. During the wear

  3. Muscle shear elastic modulus is linearly related to muscle torque over the entire range of isometric contraction intensity.

    Science.gov (United States)

    Ateş, Filiz; Hug, François; Bouillard, Killian; Jubeau, Marc; Frappart, Thomas; Couade, Mathieu; Bercoff, Jeremy; Nordez, Antoine

    2015-08-01

    Muscle shear elastic modulus is linearly related to muscle torque during low-level contractions (muscle force. However, it is not known if this relationship remains valid for higher intensities. The aim of this study was to determine: (i) the relationship between muscle shear elastic modulus and muscle torque over the entire range of isometric contraction and (ii) the influence of the size of the region of interest (ROI) used to average the shear modulus value. Ten healthy males performed two incremental isometric little finger abductions. The joint torque produced by Abductor Digiti Minimi was considered as an index of muscle torque and elastic modulus. A high coefficient of determination (R(2)) (range: 0.86-0.98) indicated that the relationship between elastic modulus and torque can be accurately modeled by a linear regression over the entire range (0% to 100% of MVC). The changes in shear elastic modulus as a function of torque were highly repeatable. Lower R(2) values (0.89±0.13 for 1/16 of ROI) and significantly increased absolute errors were observed when the shear elastic modulus was averaged over smaller ROI, half, 1/4 and 1/16 of the full ROI) than the full ROI (mean size: 1.18±0.24cm(2)). It suggests that the ROI should be as large as possible for accurate measurement of muscle shear modulus. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Modifying Young's modulus in DEM simulations based on distributions of experimental measurements

    Energy Technology Data Exchange (ETDEWEB)

    Van Lew, Jon T., E-mail: jtvanlew@fusion.ucla.edu [UCLA, MAE Department, 44-114 Engineering IV, 420 Westwood Plaza, Los Angeles, CA 90095-1597 (United States); Park, Yi-Hyun [National Fusion Research Institute, Daejeon (Korea, Republic of); Ying, Alice; Abdou, Mohamed [UCLA, MAE Department, 44-114 Engineering IV, 420 Westwood Plaza, Los Angeles, CA 90095-1597 (United States)

    2015-10-15

    Highlights: • Developing a modification to the Young's modulus of individual pebbles based on variations seen in single pebble crushing experiments. • Developing an equation to translate between single pebble crush data to a “force value” that can be applied to individual pebbles in DEM simulations. • Applying the above developments into DEM simulations on uniaxial compression tests, with parametric variations on pebble diameter distribution and pebble coefficient of friction. • Found that modified Young's modulus simulations resulted in pebbles that predicted fewer broken pebbles than the older, single value Young's modulus version of DEM models. - Abstract: The discrete element method, as currently employed by members of the fusion community, is rooted on the assumption that each pebble is a perfectly elastic material that obeys Hertz's theory for normal interaction. This assumption impacts the magnitude of inter-particle forces predicted by the models. We scrutinize the Hertzian assumption with single-pebble crush experiments with carefully recorded force-displacement responses and compare them to the non-linear forces predicted by a Hertzian pebble with bulk properties reported in literature. We found each pebble generally has a non-linear force response but with varying levels of stiffness that qualitatively matched the curves from Hertz theory. Assuming Hertzian interaction, we backed-out an elastic modulus for each pebble. We define a softening coefficient, κ, as the ratio of the pebble's elastic modulus to the sintered bulk value from literature. After determining the κ value for every pebble in our batch, we discovered a probability distribution for different batches. The distribution is attributed to the varying micro-structure of each pebble. We incorporate the results into our DEM algorithms, distributing κ values at random to pebbles satisfying the probability curves of experiments. DEM simulations of pebble beds

  5. Corneal modulus and IOP measurements in canine eyes using Goldmann applanation tonometry and Tono-pen.

    Science.gov (United States)

    Tang, Junhua; Pan, Xueliang; Weber, Paul A; Liu, Jun

    2011-10-04

    To experimentally examine the effect of corneal modulus on Goldmann applanation tonometry (GAT) and Tono-pen (Tono-pen XL, Reichert, Inc., Depew, NY) measurements of intraocular pressure (IOP) in a canine eye model. Twenty-one canine globes were recovered from healthy animals. IOP was controlled at 10, 15, 20, 30, and 40 mm Hg and measured by GAT and Tono-pen following standard protocols. The corneas were dissected and uniaxial tensile tests were performed on corneal strips. The correlation between GAT and Tono-pen errors and corneal secant modulus was evaluated using Pearson correlation coefficients. The influence of corneal thickness and the true pressure was also examined. At a true IOP of 10, 15, 20, 30, and 40 mm Hg, the GAT readings were 1.1 ± 1.0, 5.1 ± 1.5, 9.5 ± 2.0, 17.3 ± 1.6, and 25.3 ± 1.8 mm Hg, respectively. The corresponding Tono-pen readings were 7.8 ± 1.7, 12.4 ± 1.7, 16.1 ± 1.9, 22.5 ± 2.1, and 28.1 ± 2.2 mm Hg, respectively. The mean secant modulus at 1% strain of the canine corneal strips was 1.54 ± 0.43 megapascal (MPa). Corneal secant modulus was significantly correlated with GAT errors when the true IOP was 30 mm Hg (R = 0.49; P < 0.05). No significant correlation was observed between tonometric errors and corneal thickness. Both GAT and Tono-pen errors increased significantly at higher pressures (P < 0.001). Both GAT and Tono-pen underestimated IOP in canine eyes. There was preliminary experimental evidence for a correlation between corneal modulus and GAT in the canine eyes and a higher corneal modulus was associated with higher GAT readings at a certain pressure level. The tonometric errors appeared to be pressure-dependent.

  6. Dramatic Enhancement of Graphene Oxide/Silk Nanocomposite Membranes: Increasing Toughness, Strength, and Young's modulus via Annealing of Interfacial Structures.

    Science.gov (United States)

    Wang, Yaxian; Ma, Ruilong; Hu, Kesong; Kim, Sunghan; Fang, Guangqiang; Shao, Zhengzhong; Tsukruk, Vladimir V

    2016-09-21

    We demonstrate that stronger and more robust nacre-like laminated GO (graphene oxide)/SF (silk fibroin) nanocomposite membranes can be obtained by selectively tailoring the interfacial interactions between "bricks"-GO sheets and "mortar"-silk interlayers via controlled water vapor annealing. This facial annealing process relaxes the secondary structure of silk backbones confined between flexible GO sheets. The increased mobility leads to a significant increase in ultimate strength (by up to 41%), Young's modulus (up to 75%) and toughness (up to 45%). We suggest that local silk recrystallization is initiated in the proximity to GO surface by the hydrophobic surface regions serving as nucleation sites for β-sheet domains formation and followed by SF assembly into nanofibrils. Strong hydrophobic-hydrophobic interactions between GO layers with SF nanofibrils result in enhanced shear strength of layered packing. This work presented here not only gives a better understanding of SF and GO interfacial interactions, but also provides insight on how to enhance the mechanical properties for the nacre-mimic nanocomposites by focusing on adjusting the delicate interactions between heterogeneous "brick" and adaptive "mortar" components with water/temperature annealing routines.

  7. Surface tension effect on the mechanical properties of nanomaterials measured by atomic force microscopy

    Science.gov (United States)

    Cuenot, Stéphane; Frétigny, Christian; Demoustier-Champagne, Sophie; Nysten, Bernard

    2004-04-01

    The effect of reduced size on the elastic properties measured on silver and lead nanowires and on polypyrrole nanotubes with an outer diameter ranging between 30 and 250 nm is presented and discussed. Resonant-contact atomic force microscopy (AFM) is used to measure their apparent elastic modulus. The measured modulus of the nanomaterials with smaller diameters is significantly higher than that of the larger ones. The latter is comparable to the macroscopic modulus of the materials. The increase of the apparent elastic modulus for the smaller diameters is attributed to surface tension effects. The surface tension of the probed material may be experimentally determined from these AFM measurements.

  8. Determinants of Atrial Electromechanical Delay in Patients with Functional Mitral Regurgitation and Non-ischemic Dilated Cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Bengi Bakal Ruken

    2014-12-01

    Full Text Available Introduction: Atrial conduction time has important hemodynamic effects on ventricular filling and is accepted as a predictor of atrial fibrillation. In this study we assessed atrial conduction time in patients with non ischemic dilated cardiomyopathy (NIDCMP and functional mitral regurgitation (MR and aimed to determine factors predicting atrial conduction time prolongation. Methods: Sixty five patients with non ischemic dilated cardiomyopathy who have moderate to severe MR and 60 control subjects were included in the study. In addition to conventional echocardiographic measures used to asses left ventricle and MR, atrial electromechanical coupling (time interval from the onset of P wave on surface electrocardiogram [ECG] to the beginning of A wave interval with tissue Doppler echocardiography [PA], intra- and interatrial electromechanical delay (intra and inter AEMD were measured. Results: The correlations between inter AEMD and left atrial (LA size, MR volume, isovolumetric relaxation time (IVRT, deceleration time (DT, systolic pulmonary artery pressure (PAPs, E/A ratio and E/e’ were very poor. Similarly, intra AEMD was not correlated to LA size , MR volume, IVRT, DT, PAPs, E/A ratio and E/e’. However, both inter AEMD and intra AEMD had good correlation with left ventricular mass index, tenting area (TA, tenting distance (TD, coaptation septal distance (CSD, sphericity index (SI. Conclusion: Prolongation of inter and intra AEMDs were found to be well correlated with parameters reflecting left ventricular and mitral annular remodeling.

  9. Measurement of the elastic modulus of Kapton perpendicular to the plane of the film at room and cryogenic temperatures

    International Nuclear Information System (INIS)

    Davidson, M.; Bastian, S.; Markley, F.

    1992-04-01

    Understanding the short term elastic properties, (i.e. the instantaneous modulus) of Kapton is essential in determining the loss of prestress during storage and operation of SSC dipole magnets. The magnet prestress contributes directly to the coil response to the Lorentz forces during ramping. The instantaneous modulus is important in extrapolating short term stress relaxation data to longer times. Most theoretical fits assume a time independent component and a time dependent component. The former may be represented by the Kapton modulus near zero K where all relaxation processes have been ''frozen'' out. Modulus measurements at 77K and 4.2K may point to a correct value for the near zero K modulus. Three companion papers presented at this conference will be: ''Stress Relaxation in SSC 50 mm Dipole Coils'' ''Temperature Dependence of the Viscoelastic Properties of SSC Coil Insulation (Kapton)'' ''Theoretical Methods for Creep and Stress Relaxation Studies of SSC Coil.''

  10. Dilational rheology of oil/water interfaces covered by amphiphilic polysaccharides derived from dextran.

    Science.gov (United States)

    Desbrières, Jacques; López-Gonzalez, Edeluc; Aguilera-Miguel, Antonio; Sadtler, Véronique; Marchal, Philippe; Castel, Christophe; Choplin, Lionel; Durand, Alain

    2017-12-01

    This work studied the adsorption at dodecane/water interface of amphiphilic polysaccharides derived from dextran (a nonionic bacterial polysaccharide) by random attachment of phenoxy groups along the chains (between 10 and 20 attached phenoxy groups per 100 glucose repeat units). The long-time kinetics of interfacial tension decrease was satisfactorily described assuming diffusion-limited adsorption of hydrophobic units (over 4h). Dilational rheology of dodecane/water interface was studied for the first time with that kind of amphiphilic polysaccharides and evidenced a significant elastic component. For all dextran derivatives, experimental results were conveniently described using Lucassen-van den Tempel model which assumed diffusion-limited of surface active species. The characteristic frequency increased with the number of attached phenoxy groups and its order of magnitude (10 -3 -10 -2 rad.s -1 ) was consistent with estimations based on the previous model. Experimental results were compared to those obtained with commercial stabilizers like Pluronics (L64, P105, F68 and F127) and Tween 80. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Dilation of the ascending aorta in Turner syndrome - a prospective cardiovascular magnetic resonance study

    Directory of Open Access Journals (Sweden)

    Pedersen Erik M

    2011-04-01

    Full Text Available Abstract Background The risk of aortic dissection is 100-fold increased in Turner syndrome (TS. Unfortunately, risk stratification is inadequate due to a lack of insight into the natural course of the syndrome-associated aortopathy. Therefore, this study aimed to prospectively assess aortic dimensions in TS. Methods Eighty adult TS patients were examined twice with a mean follow-up of 2.4 ± 0.4 years, and 67 healthy age and gender-matched controls were examined once. Aortic dimensions were measured at nine predefined positions using 3D, non-contrast and free-breathing cardiovascular magnetic resonance. Transthoracic echocardiography and 24-hour ambulatory blood pressure were also performed. Results At baseline, aortic diameters (body surface area indexed were larger at all positions in TS. Aortic dilation was more prevalent at all positions excluding the distal transverse aortic arch. Aortic diameter increased in the aortic sinus, at the sinotubular junction and in the mid-ascending aorta with growth rates of 0.1 - 0.4 mm/year. Aortic diameters at all other positions were unchanged. The bicuspid aortic valve conferred higher aortic sinus growth rates (p Conclusion A general aortopathy is present in TS with enlargement of the ascending aorta, which is accelerated in the presence of a bicuspid aortic valve.

  12. Late complications of percutaneous tracheostomy using the balloon dilation technique.

    Science.gov (United States)

    Araujo, J B; Añón, J M; García de Lorenzo, A; García-Fernandez, A M; Esparcia, M; Adán, J; Relanzon, S; Quiles, D; de Paz, V; Molina, A

    2018-04-01

    The purpose of this study was to determine the late complications in critically ill patients requiring percutaneous tracheostomy (PT) using the balloon dilation technique. A prospective, observational cohort study was carried out. Two medical-surgical intensive care units (ICU). All mechanically ventilated adult patients consecutively admitted to the ICU with an indication of tracheostomy. All patients underwent PT according to the Ciaglia Blue Dolphin ® method, with endoscopic guidance. Survivors were interviewed and evaluated by fiberoptic laryngotracheoscopy and tracheal computed tomography at least 6 months after decannulation. Intraoperative, postoperative and long-term complications and mortality (in-ICU, in-hospital) were recorded. A total of 114 patients were included. The most frequent perioperative complication was minor bleeding (n=20) and difficult cannula insertion (n=19). Two patients had severe perioperative complications (1.7%) (major bleeding and inability to complete de procedure in one case and false passage and desaturation in the other). All survivors (n=52) were evaluated 211±28 days after decannulation. None of the patients had symptoms. Fiberoptic laryngotracheoscopy and computed tomography showed severe tracheal stenosis (>50%) in 2patients (3.7%), both with a cannulation period of over 100 days. Percutaneous tracheostomy using the Ciaglia Blue Dolphin ® technique with an endoscopic guide is a safe procedure. Severe tracheal stenosis is a late complication which although infrequent, must be taken into account due to its lack of clinical expressiveness. Evaluation should be considered in those tracheostomized critical patients who have been cannulated for a long time. Copyright © 2017 Elsevier España, S.L.U. y SEMNIM. All rights reserved.

  13. Genetic Testing for Dilated Cardiomyopathy in Clinical Practice

    Science.gov (United States)

    Lakdawala, Neal K.; Funke, Birgit H.; Baxter, Samantha; Cirino, Allison L.; Roberts, Amy E.; Judge, Daniel P.; Johnson, Nicole; Mendelsohn, Nancy J.; Morel, Chantal; Care, Melanie; Chung, Wendy K.; Jones, Carolyn; Psychogios, Apostolos; Duffy, Elizabeth; Rehm, Heidi L.; White, Emily; Seidman, J.G.; Seidman, Christine E.; Ho, Carolyn Y.

    2013-01-01

    Background Familial involvement is common in dilated cardiomyopathy (DCM) and >40 genes have been implicated in causing disease. However, the role of genetic testing in clinical practice is not well defined. We examined the experience of clinical genetic testing in a diverse DCM population to characterize the prevalence and predictors of gene mutations. Methods and Results We studied 264 unrelated adult and pediatric DCM index patients referred to 1 reference lab for clinical genetic testing. Up to 10 genes were analyzed (MYH7, TNNT2, TNNI3, TPM1, MYBPC3, ACTC, LMNA, PLN, TAZ, and LDB3), and 70% of patients were tested for all genes. The mean age was 26.6 ± 21.3 years, and 52% had a family history of DCM. Rigorous criteria were used to classify DNA variants as clinically relevant (mutations), variants of unknown clinical significance (VUS), or presumed benign. Mutations were found in 17.4% of patients, commonly involving MYH7, LMNA, or TNNT2 (78%). An additional 10.6% of patients had VUS. Genetic testing was rarely positive in older patients without a family history of DCM. Conversely in pediatric patients, family history did not increase the sensitivity of genetic testing. Conclusions Using rigorous criteria for classifying DNA variants, mutations were identified in 17% of a diverse group of DCM index patients referred for clinical genetic testing. The low sensitivity of genetic testing in DCM reflects limitations in both current methodology and knowledge of DCM-associated genes. However, if mutations are identified, genetic testing can help guide family management. PMID:22464770

  14. Genetic Modifiers of Duchenne Muscular Dystrophy and Dilated Cardiomyopathy.

    Directory of Open Access Journals (Sweden)

    Andrea Barp

    Full Text Available Dilated cardiomyopathy (DCM is a major complication and leading cause of death in Duchenne muscular dystrophy (DMD. DCM onset is variable, suggesting modifier effects of genetic or environmental factors. We aimed to determine if polymorphisms previously associated with age at loss of independent ambulation (LoA in DMD (rs28357094 in the SPP1 promoter, rs10880 and the VTTT/IAAM haplotype in LTBP4 also modify DCM onset.A multicentric cohort of 178 DMD patients was genotyped by TaqMan assays. We performed a time-to-event analysis of DCM onset, with age as time variable, and finding of left ventricular ejection fraction 70 mL/m2 as event (confirmed by a previous normal exam < 12 months prior; DCM-free patients were censored at the age of last echocardiographic follow-up.Patients were followed up to an average age of 15.9 ± 6.7 years. Seventy-one/178 patients developed DCM, and median age at onset was 20.0 years. Glucocorticoid corticosteroid treatment (n = 88 untreated; n = 75 treated; n = 15 unknown did not have a significant independent effect on DCM onset. Cardiological medications were not administered before DCM onset in this population. We observed trends towards a protective effect of the dominant G allele at SPP1 rs28357094 and recessive T allele at LTBP4 rs10880, which was statistically significant in steroid-treated patients for LTBP4 rs10880 (< 50% T/T patients developing DCM during follow-up [n = 13]; median DCM onset 17.6 years for C/C-C/T, log-rank p = 0.027.We report a putative protective effect of DMD genetic modifiers on the development of cardiac complications, that might aid in risk stratification if confirmed in independent cohorts.

  15. Characteristics of syncope in patients with dilated cardiomyopathy.

    Science.gov (United States)

    Rami, Abdel-Hadi; Lucian, Muresan; Dana, Pop; Dumitru, Zdrenghea

    2016-04-01

    Syncope carries a poor prognosis among patients with dilated cardiomyopathy (DCM). To assess the prevalence, describe the underlying mechanisms and to identify risk factors for syncope in patients with DCM. One thousand six hundred and ten medical files of 897 patients with a diagnosis of DCM were reviewed. Patients with syncope were identified and their clinical and paraclinical profiles were compared to an equal number of age- and sex-matched patients with DCM without syncope. Thirty patients (27 males) with an average age of 62.5 years were identified, corresponding to a prevalence of syncope of 3.3%. A cardiac origin of syncope was identified in 56% of patients (n=17): ventricular arrhythmias in 33% (n=10), and conduction disorders in 23% (n=7). Other mechanisms of syncope were neurally mediated in 7% (n=2) and orthostatic hypotension in 7% (n=2). In 30% of cases (n=9), the etiology was unidentified. There were no significant differences regarding the etiology of DCM, ejection fraction (35.3% vs 35.3%, p=1.0), NYHA class (mild or advanced, p=0.79) and associated conditions (hypertension, p=0.36; diabetes, p=0.75; atrial fibrillation, p=0.43; and dyslipidemia, p=0.33) between the two groups. However, among patients with syncope, patients with a noncardiac cause were more likely to have hypertension (61.53% vs 23.52%, p=0.08) and diabetes (46.15% vs 5.88%, p=0.03). In patients with DCM, syncope is a relatively rare finding. Cardiac causes (arrhythmias and conduction disorders) are responsible for the majority of cases. Risk factors for syncope in these patients remain to be determined. Copyright © 2015 Cardiological Society of India. Published by Elsevier B.V. All rights reserved.

  16. Efficiency factor and modulus of elasticity of lightweight concrete with expanded clay aggregate

    Directory of Open Access Journals (Sweden)

    W.G Moravia

    Full Text Available Nowadays lightweight concrete is used on a large scale for structural purposes and to reduce the self-weight of structures. Specific grav- ity, compressive strength, strength/weight ratio and modulus of elasticity are important factors in the mechanical behavior of structures. This work studies these properties in lightweight aggregate concrete (LWAC and normal-weight concrete (NWC, comparing them. Spe- cific gravity was evaluated in the fresh and hardened states. Four mixture proportions were adopted to evaluate compressive strength. For each proposed mixture proportion of the two concretes, cylindrical specimens were molded and tested at ages of 3, 7 and 28 days. The modulus of elasticity of the NWC and LWAC was analyzed by static, dynamic and empirical methods. The results show a larger strength/ weight ratio for LWAC, although this concrete presented lower compressive strength.

  17. High modulus rare earth and beryllium containing silicate glass compositions. [for glass reinforcing fibers

    Science.gov (United States)

    Bacon, J. F. (Inventor)

    1976-01-01

    Glass compositions having a Young's modulus of at least 16 million psi and a specific modulus of at least 110 million inches consisting essentially of approximately, by weight, 20 to 43% SiO2, 8 to 21% Al2O3, 4 to 10% BeO, 27 to 58% of at least one oxide selected from a first group consisting of Y2O3, La2O3, Nd2O3, Ce2O3, Ce2O3, and the mixed rare earth oxides, and 3 to 12% of at least one oxide selected from a second group consisting of MgO, ZrO2, ZnO and CaO are described. The molar ratio of BeO to the total content of the first group oxides is from 1.0 to 3.0.

  18. Poisson's ratio and Young's modulus of lipid bilayers in different phases

    Directory of Open Access Journals (Sweden)

    Tayebeh eJadidi

    2014-04-01

    Full Text Available A general computational method is introduced to estimate the Poisson's ratio for membranes with small thickness.In this method, the Poisson's ratio is calculated by utilizing a rescaling of inter-particle distancesin one lateral direction under periodic boundary conditions. As an example for the coarse grained lipid model introduced by Lenz and Schmid, we calculate the Poisson's ratio in the gel, fluid, and interdigitated phases. Having the Poisson's ratio, enable us to obtain the Young's modulus for the membranes in different phases. The approach may be applied to other membranes such as graphene and tethered membranes in orderto predict the temperature dependence of its Poisson's ratio and Young's modulus.

  19. The effect of concrete vertical construction joints on the modulus of rupture

    Directory of Open Access Journals (Sweden)

    Camille A. Issa

    2014-01-01

    In this study, seven different concrete mix designs were used. From each concrete mix, six plain concrete beams were poured, half of which were monolithic and the other half with a vertical construction joint at the beam center. Four cylinders per design mix were casted for the purpose of obtaining the mix compressive strength. The experimental results indicate that for monolithic beams, the ACI Code always underestimates the modulus of rupture, whereas in the presence of a vertical construction joint, the conducted experiments yield a significant loss in the modulus of rupture of concrete that varies between 24% and 83%. Thus, there is a clear justification for providing dowels at construction joints in order to assure continuity in strength over joints in plain concrete.

  20. Printing Three-Dimensional Heterogeneities in the Elastic Modulus of an Elastomeric Matrix.

    Science.gov (United States)

    Abdel Fattah, Abdel Rahman; Ghosh, Suvojit; Puri, Ishwar K

    2016-05-04

    We present a rapid and controllable method to create microscale heterogeneities in the 3D stiffness of a soft material by printing patterns with a ferrofluid ink. An ink droplet moved through a liquid polydimethylsiloxane (PDMS) volume using an externally applied magnetic field sheds clusters of magnetic nanoparticles (MNPs) in its wake. By varying the field spatiotemporally, a well-defined three-dimensional curvilinear feature is printed that contains MNP clusters. Subsequent cross-linking of the PDMS preserves the feature in place after the magnetic field is removed. Since the ferrofluid ink interferes with the cross-linking of PDMS, a 3D print containing ink density variations leads to corresponding spatial deviations in the elastic modulus of the matrix. The modulus is mapped in the experiments with atomic force microscopy. This rapid method to print 3D heterogeneities in soft matter promises the ability to mimic mechanical variations that occur in natural biomaterials.

  1. The information exchange between moduluses in the system of module programming of the computation complexes

    International Nuclear Information System (INIS)

    Zinin, A.I.; Kolesov, V.E.; Nevinitsa, A.I.

    1975-01-01

    The report contains description of the method of construction of computer programs complexes for computation purposes for M-220 computers using the ALGOL-60 code for programming. The complex is organised on the modulus system principle and can include substantial number of modulus programs. The information exchange between separate moduli is done by means of special interpreting program and the information unit exchanged is a specially arranged file of data. For addressing to the interpreting program in the ALGOL-60 frameworks small number of specially created procedure-codes is used. The method proposed gives possibilities to program separate moduli of the complex independently and to expand the complex if necessary. In this case separate moduli or groups of moduli depending on the method of segmentation of the general problem solved by the complex will be of the independent interest and could be used out of the complex as traditional programs. (author)

  2. Percutaneous tracheostomy with the guide wire dilating forceps technique : presentation of 171 consecutive patients

    NARCIS (Netherlands)

    Fikkers, Bernard G; van Heerbeek, Niels; Krabbe, Paul F M; Marres, Henri A M; van den Hoogen, Frank J A

    BACKGROUND: Evaluation of percutaneous tracheostomy (PT) with the guide wire dilating forceps (GWDF) technique. METHODS: Prospective study of perioperative complications, retrospective analysis of early and late complications in an ICU in a teaching university hospital. RESULTS: The success rate of

  3. Percutaneous tracheostomy with the guide wire dilating forceps technique: presentation of 171 consecutive patients.

    NARCIS (Netherlands)

    Fikkers, B.G.; Heerbeek, N. van; Krabbe, P.F.M.; Marres, H.A.M.; Hoogen, F.J.A. van den

    2002-01-01

    BACKGROUND: Evaluation of percutaneous tracheostomy (PT) with the guide wire dilating forceps (GWDF) technique. METHODS: Prospective study of perioperative complications, retrospective analysis of early and late complications in an ICU in a teaching university hospital. RESULTS: The success rate of

  4. Danish Guidelines 2015 for percutaneous Dilatational Tracheostomy in the Intensive Care Unit

    DEFF Research Database (Denmark)

    Madsen, Kristian Rørbæk; Guldager, Henrik; Rewers, Mikael

    2015-01-01

    Percutaneous dilatational tracheostomy is a common procedure in intensive care. This updated Danish national guideline describes indications, contraindications and complications, and gives recommendations for timing, anaesthesia, and technique, use of fibre bronchoscopy and ultrasound guidance...

  5. Cerebrovascular effects of angiotensin converting enzyme inhibition involve large artery dilatation in rats

    DEFF Research Database (Denmark)

    Postiglione, A; Bobkiewicz, T; Vinholdt-Pedersen, E

    1991-01-01

    The aim of the study was to selectively examine the effects of converting enzyme inhibition on the large brain arteries by using concomitant inhibition of carbonic anhydrase to cause severe dilatation of mainly parenchymal resistance vessels....

  6. Subtle abnormalities in contractile function are an early manifestation of sarcomere mutations in dilated cardiomyopathy

    DEFF Research Database (Denmark)

    Lakdawala, Neal K; Thune, Jens J; Colan, Steven D

    2012-01-01

    Sarcomere mutations cause both dilated cardiomyopathy (DCM) and hypertrophic cardiomyopathy (HCM); however, the steps leading from mutation to disease are not well described. By studying mutation carriers before a clinical diagnosis develops, we characterize the early manifestations of sarcomere...

  7. ACE I/D polymorphism in Indian patients with hypertrophic cardiomyopathy and dilated cardiomyopathy

    DEFF Research Database (Denmark)

    Rai, Taranjit Singh; Dhandapany, Perundurai Subramaniam; Ahluwalia, Tarun Veer Singh

    2008-01-01

    The study was carried to determine the association of angiotensin converting enzyme (ACE) insertion/deletion (I/D) polymorphism with the risk of hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), and restrictive cardiomyopathy (RCM)....

  8. Transcatheter pulmonary valve perforation and balloon dilatation in neonates with pulmonary atresia and intact ventricular septum

    NARCIS (Netherlands)

    Gerestein, C.G.; Berger, R.M.F.; Dalinghaus, M.; Bogers, A.J.J.C.; Witsenburg, M.

    2003-01-01

    BACKGROUND: Pulmonary atresia and intact ventricular septum is characterised by a great morphological variety. Treatment is not uniform. OBJECTIVE: To evaluate our experience with transcatheter valvotomy and balloon dilatation in neonates with pulmonary atresia and intact ventricular septum. DESIGN:

  9. [Early complications of pneumatic dilatation in the treatment of primary motility disorders of the esophagus].

    Science.gov (United States)

    Sala, T; Ponce, J; Pertejo, V; Linares, M; Garrigues, V; Berenguer, J

    1990-04-01

    We analyze the incidence and evolution of the early complications of 96 consecutive patients with primary esophagus motor disorders, treated with pneumatic dilatation under endoscopic control (1.4 sessions per patient). In 4 (0.042/patient, 0.029/dilatation) patients the esophagus was perforated; the diagnosis was made in the first 24 hours; pneumomediastinum was a constant finding in the radiological exploration. In three cases the complication was suspected because of the apparition of sustained thoracic pain after the dilatation maneuver and in one case the presentation symptom was bleeding of cardial mucosa, larger than usual, at the end of the dilatation. The four patients evolved favorably with conservative treatment (avoidance of oral food intake, gastroesophageal aspiration, antibiotic therapy and parenteral nutrition).

  10. Predictors for outcome of failure of balloon dilatation in patients with achalasia

    NARCIS (Netherlands)

    J. Alderliesten (Joyce); J.M. Conchillo; I. Leeuwenburgh (Ivonne); E.W. Steyerberg (Ewout); E.J. Kuipers (Ernst)

    2011-01-01

    textabstractBackground: Pneumatic balloon dilatation (PD) is a regular treatment modality for achalasia. The reported success rates of PD vary. Recurrent symptoms often require repeated PD or surgery. Objective: To identify predicting factors for symptom recurrence requiring repeated treatment.

  11. Mechanics of active surfaces

    Science.gov (United States)

    Salbreux, Guillaume; Jülicher, Frank

    2017-09-01

    We derive a fully covariant theory of the mechanics of active surfaces. This theory provides a framework for the study of active biological or chemical processes at surfaces, such as the cell cortex, the mechanics of epithelial tissues, or reconstituted active systems on surfaces. We introduce forces and torques acting on a surface, and derive the associated force balance conditions. We show that surfaces with in-plane rotational symmetry can have broken up-down, chiral, or planar-chiral symmetry. We discuss the rate of entropy production in the surface and write linear constitutive relations that satisfy the Onsager relations. We show that the bending modulus, the spontaneous curvature, and the surface tension of a passive surface are renormalized by active terms. Finally, we identify active terms which are not found in a passive theory and discuss examples of shape instabilities that are related to active processes in the surface.

  12. Determination of Rock Mass Modulus Using the Plate Loading Method at Yucca Mountain, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    Finley, R.E.; George, J.T.; Riggins, M.

    1999-08-02

    A suite of plate loading tests has recently been conducted by Sandia National Laboratories at the Exploratory Studies Facility at Yucca Mountain, Nevada. Fielding of these in situ tests as well as other approaches undertaken for the determination of rock mass modulus are described. The various methodologies are evaluated and their data compared. Calculation by existing empirical methods and numerical modeling are compared to each other as well as to field data.

  13. Genetic variation in basic density and modulus of elasticity of coastal Douglas-fir.

    Science.gov (United States)

    G.R. Johnson; B.L. Gartner

    2006-01-01

    Douglas-fir trees from 39 open-pollinated families at four test locations were assessed to estimate heritability of modulus of elasticity (MOE) and basic density. Heritability estimates of MOE (across-site h = 0.55) were larger than those for total height (0.15) and diameter at breast height (DBH; 0.29), and similar to those for density (0.59)....

  14. A vibrational approach to determine the elastic modulus of individual thin films in multilayers

    Energy Technology Data Exchange (ETDEWEB)

    López-Puerto, A. [Centro de Investigación Científica de Yucatán, A.C., Unidad de Materiales, Calle 43 # 130, Col. Chuburná de Hidalgo, 97200 Mérida, Yucatán (Mexico); Universidad Autónoma de Yucatán, Facultad de Ingeniería, Av. Industrias no contaminantes por Periférico Norte, Cordemex, 97310 Mérida, Yucatán (Mexico); Avilés, F., E-mail: faviles@cicy.mx [Centro de Investigación Científica de Yucatán, A.C., Unidad de Materiales, Calle 43 # 130, Col. Chuburná de Hidalgo, 97200 Mérida, Yucatán (Mexico); Gamboa, F.; Oliva, A.I. [Centro de Investigación y de Estudios Avanzados del IPN, Unidad Mérida, Depto. de Física Aplicada, Km. 6 Antigua Carretera a Progreso, 97310 Mérida, Yucatán (Mexico)

    2014-08-28

    A vibrational approach is presented to determine the elastic modulus of individual thin films deposited over a thicker substrate in multilayered systems. The approach requires measurement of the fundamental frequency of the multilayer and a laminated beam model for data reduction. A one-dimensional model based on classical laminated beam theory is introduced to provide a simple analytical approximation of the natural frequency of thin multilayered materials deposited over a significantly thicker substrate in cantilever beam configuration. The model has the advantage of providing an easy-to-use analytical expression for the natural frequency of a multilayered beam in terms of the elastic moduli of each layer, which can be inverted to calculate the elastic modulus of any individual layer if the elastic modulus of the remaining layers is known, and the natural frequency of the multilayered beam is measured. The limits of applicability of the proposed model are investigated by comparing its predictions of the fundamental frequency to those of an existent analytical model for bilayers and finite element analysis of materials comprising two and three dissimilar layers. The proposed model is applied to obtain the elastic modulus of Al and Au thin films in an Al/Au/Kapton multilayer. - Highlights: • A vibrational approach is proposed to measure elastic moduli of thin multilayers. • A vibratory model based on laminated theory is developed. • The model predictions of frequency are in agreement with finite element analysis. • The elastic moduli of Au and Al in an Al/Au/Kapton multilayer are measured.

  15. Production of a low young modulus titanium alloy by powder metallurgy

    OpenAIRE

    Santos,Dalcy Roberto dos; Henriques,Vinicius André Rodrigues; Cairo,Carlos Alberto Alves; Pereira,Marcelo dos Santos

    2005-01-01

    Titanium alloys have several advantages over ferrous and non-ferrous metallic materials, such as high strengthto-weight ratio and excellent corrosion resistance. A blended elemental titanium powder metallurgy process has been developed to offer low cost commercial products. The process employs hydride-dehydride (HDH) powders as raw material. In this work, results of the Ti-35Nb alloy sintering are presented. This alloy due to its lower modulus of elasticity and high biocompatibility is a prom...

  16. Vitamin A deficiency alters the pulmonary parenchymal elastic modulus and elastic fiber concentration in rats

    Directory of Open Access Journals (Sweden)

    Holmes Amey J

    2005-07-01

    Full Text Available Abstract Background Bronchial hyperreactivity is influenced by properties of the conducting airways and the surrounding pulmonary parenchyma, which is tethered to the conducting airways. Vitamin A deficiency (VAD is associated with an increase in airway hyperreactivity in rats and a decrease in the volume density of alveoli and alveolar ducts. To better define the effects of VAD on the mechanical properties of the pulmonary parenchyma, we have studied the elastic modulus, elastic fibers and elastin gene-expression in rats with VAD, which were supplemented with retinoic acid (RA or remained unsupplemented. Methods Parenchymal mechanics were assessed before and after the administration of carbamylcholine (CCh by determining the bulk and shear moduli of lungs that that had been removed from rats which were vitamin A deficient or received a control diet. Elastin mRNA and insoluble elastin were quantified and elastic fibers were enumerated using morphometric methods. Additional morphometric studies were performed to assess airway contraction and alveolar distortion. Results VAD produced an approximately 2-fold augmentation in the CCh-mediated increase of the bulk modulus and a significant dampening of the increase in shear modulus after CCh, compared to vitamin A sufficient (VAS rats. RA-supplementation for up to 21 days did not reverse the effects of VAD on the elastic modulus. VAD was also associated with a decrease in the concentration of parenchymal elastic fibers, which was restored and was accompanied by an increase in tropoelastin mRNA after 12 days of RA-treatment. Lung elastin, which was resistant to 0.1 N NaOH at 98°, decreased in VAD and was not restored after 21 days of RA-treatment. Conclusion Alterations in parenchymal mechanics and structure contribute to bronchial hyperreactivity in VAD but they are not reversed by RA-treatment, in contrast to the VAD-related alterations in the airways.

  17. Effect of microbial activity on penetrometer resistance and elastic modulus of soil at different temperatures.

    Science.gov (United States)

    Gao, W; Muñoz-Romero, V; Ren, T; Ashton, R W; Morin, M; Clark, I M; Powlson, D S; Whalley, W R

    2017-07-01

    We explore the effect of microbial activity stimulated by root exudates on the penetrometer resistance of soil and its elastic modulus. This is important because it is a measure of the mechanical strength of soil and it correlates closely with the rate of elongation of roots. A sandy soil was incubated with a synthetic root exudate at different temperatures, for different lengths of time and with selective suppression of either fungi or bacteria. The shape of the temperature response of penetrometer resistance in soil incubated with synthetic exudate was typical of a poikilothermic temperature response. Both penetrometer resistance and small strain shear modulus had maximum values between 25 and 30°C. At temperatures of 20°C and less, there was little effect of incubation with synthetic root exudate on the small strain shear modulus, although penetrometer resistance did increase with temperature over this range (4-20°C). This suggests that in this temperature range the increase in penetrometer resistance was related to a greater resistance to plastic deformation. At higher temperatures (> 25°C) penetrometer resistance decreased. Analysis of the DNA sequence data showed that at 25°C the number of Streptomyces (Gram-positive bacteria) increased, but selective suppression of either fungi or bacteria suggested that fungi have the greater role with respect to penetrometer resistance. Effect of microbial activity stimulated by synthetic root exudates on the mechanical properties.We compared penetrometer measurements and estimates of elastic modulus with microbial community.Penetrometer resistance of soil showed a poikilothermic temperature response.Penetrometer resistance might be affected more by fungi than bacteria.

  18. Characterizing the variation of small strain shear modulus for silt and sand during hydraulic hysteresis

    OpenAIRE

    Khosravi Ali; Rahimi Mehrzad; Shahbazan Parisa; Pak Ali; Gheibi Amin

    2016-01-01

    Experimental studies have indicated that the small strain shear modulus, Gmax, of unsaturated silt and clay has a greater amount during imbibition than during drainage, when presented as a function of matric suction. However, due to material properties and inter-particle forces, different behavior is expected in the case of sand. Although considerable research has been devoted in recent years to characterize the behaviour of Gmax of sand during drainage, rather less attention has been paid to...

  19. An autonomic self-healing organogel with a photo-mediated modulus

    KAUST Repository

    Xiong, Yubing

    2016-11-15

    A new method is described for fabricating autonomic, self-healing, deformable organogels. We combined imidazolium-based poly(ionic liquid) (PIL) and azobenzene-grafted poly(carboxylic acid) (PAA-Azo) in N,N-dimethyl formamide. Further, complexing PIL with unirradiated (trans) or irradiated (cis) PAA-Azo tuned the elastic modulus of the organogel. © 2016 The Royal Society of Chemistry.

  20. Temperature, Frequency, and Young’s Modulus of an Aluminum Tuning Fork

    Directory of Open Access Journals (Sweden)

    Zachery L. Greer

    2011-01-01

    Full Text Available The frequency produced by a standard C (523.3 Hz aluminum alloy tuning fork when struck at temperatures ranging from 29 ̊C to 300 ̊C was studied. It was found that frequency decreased with increasing temperature with an inverse exponential relationship. The frequency was used to calculate Young’s Modulus for aluminum, with the results being in close agreement with published values.