WorldWideScience

Sample records for void reactivity studies

  1. Physics Study of Canada Deuterium Uranium Lattice with Coolant Void Reactivity Analysis

    Directory of Open Access Journals (Sweden)

    Jinsu Park

    2017-02-01

    Full Text Available This study presents a coolant void reactivity analysis of Canada Deuterium Uranium (CANDU-6 and Advanced Canada Deuterium Uranium Reactor-700 (ACR-700 fuel lattices using a Monte Carlo code. The reactivity changes when the coolant was voided were assessed in terms of the contributions of four factors and spectrum shifts. In the case of single bundle coolant voiding, the contribution of each of the four factors in the ACR-700 lattice is large in magnitude with opposite signs, and their summation becomes a negative reactivity effect in contrast to that of the CANDU-6 lattice. Unlike the coolant voiding in a single fuel bundle, the 2 × 2 checkerboard coolant voiding in the ACR-700 lattice shows a positive reactivity effect. The neutron current between the no-void and voided bundles, and the four factors of each bundle were analyzed to figure out the mechanism of the positive coolant void reactivity of the checkerboard voiding case. Through a sensitivity study of fuel enrichment, type of burnable absorber, and moderator to fuel volume ratio, a design strategy for the CANDU reactor was suggested in order to achieve a negative coolant void reactivity even for the checkerboard voiding case.

  2. Physics study of Canada deuterium uranium lattice with coolant void reactivity analysis

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jin Su; Lee, Hyun Suk; Tak, Tae Woo; Lee, Deok Jung [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of); Shin, Ho Cheol [Korea Hydro and Nuclear Power Central Research Institute (KHNP-CRI), Daejeon (Korea, Republic of)

    2017-02-15

    This study presents a coolant void reactivity analysis of Canada Deuterium Uranium (CANDU)-6 and Advanced Canada Deuterium Uranium Reactor-700 (ACR-700) fuel lattices using a Monte Carlo code. The reactivity changes when the coolant was voided were assessed in terms of the contributions of four factors and spectrum shifts. In the case of single bundle coolant voiding, the contribution of each of the four factors in the ACR-700 lattice is large in magnitude with opposite signs, and their summation becomes a negative reactivity effect in contrast to that of the CANDU-6 lattice. Unlike the coolant voiding in a single fuel bundle, the 2 x 2 checkerboard coolant voiding in the ACR-700 lattice shows a positive reactivity effect. The neutron current between the no-void and voided bundles, and the four factors of each bundle were analyzed to figure out the mechanism of the positive coolant void reactivity of the checkerboard voiding case. Through a sensitivity study of fuel enrichment, type of burnable absorber, and moderator to fuel volume ratio, a design strategy for the CANDU reactor was suggested in order to achieve a negative coolant void reactivity even for the checkerboard voiding case.

  3. Effect of nonlinear void reactivity on bifurcation characteristics of a lumped-parameter model of a BWR: A study relevant to RBMK

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Dinkar, E-mail: dinkar@iitk.ac.in [Nuclear Engineering and Technology Program, Indian Institute of Technology Kanpur, Kanpur 208 016 (India); Kalra, Manjeet Singh, E-mail: drmanjeet.singh@dituniversity.edu.in [DIT University, Dehradun 248 009 (India); Wahi, Pankaj, E-mail: wahi@iitk.ac.in [Department of Mechanical Engineering, Indian Institute of Technology Kanpur, Kanpur 208 016 (India)

    2017-04-15

    Highlights: • A simplified model with nonlinear void reactivity feedback is studied. • Method of multiple scales for nonlinear analysis and oscillation characteristics. • Second order void reactivity dominates in determining system dynamics. • Opposing signs of linear and quadratic void reactivity enhances global safety. - Abstract: In the present work, the effect of nonlinear void reactivity on the dynamics of a simplified lumped-parameter model for a boiling water reactor (BWR) is investigated. A mathematical model of five differential equations comprising of neutronics and thermal-hydraulics encompassing the nonlinearities associated with both the reactivity feedbacks and the heat transfer process has been used. To this end, we have considered parameters relevant to RBMK for which the void reactivity is known to be nonlinear. A nonlinear analysis of the model exploiting the method of multiple time scales (MMTS) predicts the occurrence of the two types of Hopf bifurcation, namely subcritical and supercritical, leading to the evolution of limit cycles for a range of parameters. Numerical simulations have been performed to verify the analytical results obtained by MMTS. The study shows that the nonlinear reactivity has a significant influence on the system dynamics. A parametric study with varying nominal reactor power and operating conditions in coolant channel has also been performed which shows the effect of change in concerned parameter on the boundary between regions of sub- and super-critical Hopf bifurcations in the space constituted by the two coefficients of reactivities viz. the void and the Doppler coefficient of reactivities. In particular, we find that introduction of a negative quadratic term in the void reactivity feedback significantly increases the supercritical region and dominates in determining the system dynamics.

  4. CTF Void Drift Validation Study

    Energy Technology Data Exchange (ETDEWEB)

    Salko, Robert K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gosdin, Chris [Pennsylvania State Univ., University Park, PA (United States); Avramova, Maria N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gergar, Marcus [Pennsylvania State Univ., University Park, PA (United States)

    2015-10-26

    This milestone report is a summary of work performed in support of expansion of the validation and verification (V&V) matrix for the thermal-hydraulic subchannel code, CTF. The focus of this study is on validating the void drift modeling capabilities of CTF and verifying the supporting models that impact the void drift phenomenon. CTF uses a simple turbulent-diffusion approximation to model lateral cross-flow due to turbulent mixing and void drift. The void drift component of the model is based on the Lahey and Moody model. The models are a function of two-phase mass, momentum, and energy distribution in the system; therefore, it is necessary to correctly model the ow distribution in rod bundle geometry as a first step to correctly calculating the void distribution due to void drift.

  5. Sodium void reactivity comparison for advanced liquid-metal reactor fuels

    Energy Technology Data Exchange (ETDEWEB)

    Dobbin, K.D.; Kessler, S.F.; Gedeon, S.R.; Omberg, R.P. (Westinghouse Hanford Co., Richland, WA (United States))

    1991-01-01

    The advanced liquid-metal reactor (ALMR) program in the US is based on metal as the reference fuel because of its favorable neutronic feedback characteristics for passive safety. Favorable relationships exist between core performance and safety that provide a passively safe metal fuel system with a large margin to sodium boiling. Because of this, the reduction of the positive sodium void coefficient of reactivity is not an overriding design objective. A positive sodium void effect with metal fuel is due to neutron spectral hardening that dominates capture and leakage changes during sodium voiding. This can produce as much as 5-$ positive sodium void reactivity for mixed plutonium-uranium fuel in a smaller core designed for a near-zero burnup reactivity swing. It is possible to reduce the positive void feedback and its effect on hypothetical loss-of-flow (LOF) scenarios with a commensurate increase in burnup swing. However, metal fuel's small Doppler coefficient, excellent fuel conductivity, and resultant small temperature gradients provide less reactivity feedback to handle postulated transient overpower (TOP) events for cores with significant burnup reactivity swings. The purpose of this work was to study the relationship between reduction of the sodium void and the resultant increase in the burnup reactivity swing for an ALMR modeled with metal, nitride, and oxide fuel.

  6. Reactivity effects of void formations in a solution critical assembly

    Energy Technology Data Exchange (ETDEWEB)

    Walters, Steven G. [Univ. of New Mexico, Albuquerque, NM (United States)

    1994-01-01

    SHEBA II (Solution High Energy Burst Assembly) was constructed in order to better understand the neutronics of solutions of fissile materials. In order to estimate the effect on criticality from the formation of bubbles, models were devised in MCNP (Monte Carlo Neutron Photon transport code) and THREEDANT (THREE dimensional, Diffusion-Accelerated, Neutral-Particle Transport). It was found that the formation of voids in all but the outside bottom edge of the assembly cylinder tend to act as a negative insertion of reactivity. Also, an experiment has been designed which will verify the results of the codes.

  7. Conclusive evidence of abrupt coagulation inside the void during cyclic nanoparticle formation in reactive plasma

    Energy Technology Data Exchange (ETDEWEB)

    Wetering, F. M. J. H. van de; Nijdam, S.; Beckers, J. [Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

    2016-07-25

    In this letter, we present scanning electron microscopy (SEM) results that confirm in a direct way our earlier explanation of an abrupt coagulation event as the cause for the void hiccup. In a recent paper, we reported on the fast and interrupted expansion of voids in a reactive dusty argon–acetylene plasma. The voids appeared one after the other, each showing a peculiar, though reproducible, behavior of successive periods of fast expansion, abrupt contraction, and continued expansion. The abrupt contraction was termed “hiccup” and was related to collective coagulation of a new generation of nanoparticles growing in the void using relatively indirect methods: electron density measurements and optical emission spectroscopy. In this letter, we present conclusive evidence using SEM of particles collected at different moments in time spanning several growth cycles, which enables us to follow the nanoparticle formation process in great detail.

  8. Effects of Voids on Concrete Tensile Fracturing: A Mesoscale Study

    Directory of Open Access Journals (Sweden)

    Lei Xu

    2017-01-01

    Full Text Available A two-dimensional mesoscale modeling framework, which considers concrete as a four-phase material including voids, is developed for studying the effects of voids on concrete tensile fracturing under the plane stress condition. Aggregate is assumed to behave elastically, while a continuum damaged plasticity model is employed to describe the mechanical behaviors of mortar and ITZ. The effects of voids on the fracture mechanism of concrete under uniaxial tension are first detailed, followed by an extensive investigation of the effects of void volume fraction on concrete tensile fracturing. It is found that both the prepeak and postpeak mesoscale cracking in concrete are highly affected by voids, and there is not a straightforward relation between void volume fraction and the postpeak behavior due to the randomness of void distribution. The fracture pattern of concrete specimen with voids is controlled by both the aggregate arrangement and the distribution of voids, and two types of failure modes are identified for concrete specimens under uniaxial tension. It is suggested that voids should be explicitly modeled for the accurate fracturing simulation of concrete on the mesoscale.

  9. Sodium-cooled fast reactor (SFR) fuel assembly design with graphite-moderating rods to reduce the sodium void reactivity coefficient

    Energy Technology Data Exchange (ETDEWEB)

    Won, Jong Hyuck; Cho, Nam Zin, E-mail: nzcho@kaist.ac.kr; Park, Hae Min; Jeong, Yong Hoon, E-mail: jeongyh@kaist.ac.kr

    2014-12-15

    Highlights: • The graphite rod-inserted SFR fuel assembly is proposed to achieve low sodium void reactivity. • The neutronics/thermal-hydraulics analyses are performed for the proposed SFR cores. • The sodium void reactivity is improved about 960–1030 pcm compared to reference design. - Abstract: The concept of a graphite-moderating rod-inserted sodium-cooled fast reactor (SFR) fuel assembly is proposed in this study to achieve a low sodium void reactivity coefficient. Using this concept, two types of SFR cores are analyzed; the proposed SFR type 1 core has new SFR fuel assemblies at the inner/mid core regions while the proposed SFR type 2 core has a B{sub 4}C absorber sandwich in the middle of the active core region as well as new SFR fuel assemblies at the inner/mid core regions. For the proposed SFR core designs, neutronics and thermal-hydraulic analyses are performed using the DIF3D, REBUS3, and the MATRA-LMR codes. In the neutronics analysis, the sodium void reactivity coefficient is obtained in various void situations. The two types of proposed core designs reduce the sodium void reactivity coefficient by about 960–1030 pcm compared to the reference design. However, the TRU enrichment for the proposed SFR core designs is increased. In the thermal hydraulic analysis, the temperature distributions are calculated for the two types of proposed core designs and the mass flow rate is optimized to satisfy the design constraints for the highest power generating assembly. The results of this study indicate that the proposed SFR assembly design concept, which adopts graphite-moderating rods which are inserted into the fuel assembly, can feasibly minimize the sodium void reactivity coefficient. Single TRU enrichment and an identical fuel slug diameter throughout the SFR core are also achieved because the radial power peak can be flattened by varying the number of moderating rods in each core region.

  10. Nuclear data sensitivity and uncertainty assessment of sodium voiding reactivity coefficients of an ASTRID-like sodium fast reactor

    Science.gov (United States)

    Nuria, García-Herranz; Anne-Laurène, Panadero; Ana, Martinez; Sandro, Pelloni; Konstantin, Mikityuk; Andreas, Pautz

    2017-09-01

    The EU 7th Framework ESNII+ project was launched in 2013 with the strategic orientation of preparing ESNII for Horizon 2020. ESNII stands for the European Industrial Initiative on Nuclear Energy, created by the European Commission in 2010 to promote the development of a new generation of nuclear systems in order to provide a sustainable solution to cope with Europe's growing energy needs while meeting the greenhouse gas emissions reduction target. The designs selected by the ESNII+ project are technological demonstrators of Generation-IV systems. The prototype for the sodium cooled fast reactor technology is ASTRID (standing for Advanced Sodium Technological Reactor for Industrial Demonstration), which detailed design phase is foreseen to be initiated in 2019. The ASTRID core has a peculiar design which was created in order to tackle the main neutronic challenge of sodium cooled fast reactors: the inherent overall positive reactivity feedback in case of sodium voiding occurring in the core. Indeed, the core is claimed by its designers to have an overall negative reactivity feedback in this scenario. This feature was demonstrated for an ASTRID-like core within the ESNII+ framework studies performed by nine European institutions. In order to shift the paradigm towards best-estimate plus uncertainties, the nuclear data sensitivity analysis and uncertainty propagation on reactivity coefficients has to be carried out. The goal of this work is to assess the impact of nuclear data uncertainties on sodium voiding reactivity feedback coefficients in order to get a more complete picture of the actual safety margins of the ASTRID low void-core design. The nuclear data sensitivity analysis is performed in parallel using SCALE TSUNAMI-3D and the newly developed GPT SERPENT 2 module. A comparison is carried out between the two methodologies. Uncertainty on the sodium reactivity feedbacks is then calculated using TSAR module of SCALE and the necessary safety margins conclusions

  11. Nuclear data sensitivity and uncertainty assessment of sodium voiding reactivity coefficients of an ASTRID-like sodium fast reactor

    Directory of Open Access Journals (Sweden)

    Nuria García-Herranz

    2017-01-01

    Full Text Available The EU 7th Framework ESNII+ project was launched in 2013 with the strategic orientation of preparing ESNII for Horizon 2020. ESNII stands for the European Industrial Initiative on Nuclear Energy, created by the European Commission in 2010 to promote the development of a new generation of nuclear systems in order to provide a sustainable solution to cope with Europe’s growing energy needs while meeting the greenhouse gas emissions reduction target. The designs selected by the ESNII+ project are technological demonstrators of Generation-IV systems. The prototype for the sodium cooled fast reactor technology is ASTRID (standing for Advanced Sodium Technological Reactor for Industrial Demonstration, which detailed design phase is foreseen to be initiated in 2019. The ASTRID core has a peculiar design which was created in order to tackle the main neutronic challenge of sodium cooled fast reactors: the inherent overall positive reactivity feedback in case of sodium voiding occurring in the core. Indeed, the core is claimed by its designers to have an overall negative reactivity feedback in this scenario. This feature was demonstrated for an ASTRID-like core within the ESNII+ framework studies performed by nine European institutions. In order to shift the paradigm towards best-estimate plus uncertainties, the nuclear data sensitivity analysis and uncertainty propagation on reactivity coefficients has to be carried out. The goal of this work is to assess the impact of nuclear data uncertainties on sodium voiding reactivity feedback coefficients in order to get a more complete picture of the actual safety margins of the ASTRID low void-core design. The nuclear data sensitivity analysis is performed in parallel using SCALE TSUNAMI-3D and the newly developed GPT SERPENT 2 module. A comparison is carried out between the two methodologies. Uncertainty on the sodium reactivity feedbacks is then calculated using TSAR module of SCALE and the necessary safety

  12. Performance of Trasuranic-Loaded Fully Ceramic Micro-Encapsulated Fuel in LWRs Interim Report, Including Void Reactivity Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Michael A. Pope; Brian Boer; Gilles Youinou; Abderrafi M. Ougouag

    2011-03-01

    The current focus of the Deep Burn Project is on once-through burning of transuranice (TRU) in light water reactors (LWRs). The fuel form is called Fully-Ceramic Micro-encapsulated (FCM) fuel, a concept that borrows the tri-isotropic (TRISO) fuel particle design from high-temperature reactor technology. In the Deep Burn LWR (DB-LWR) concept, these fuel particles would be pressed into compacts using SiC matrix material and loaded into fuel pins for use in conventional LWRs. The TRU loading comes from the spent fuel of a conventional LWR after 5 years of cooling. Unit cell calculations have been performed using the DRAGON-4 code in order assess the physics attributes of TRU-only FCM fuel in an LWR lattice. Depletion calculations assuming an infinite lattice condition were performed with calculations of various reactivity coefficients performed at each step. Unit cells containing typical UO2 and MOX fuel were analyzed in the same way to provide a baseline against which to compare the TRU-only FCM fuel. Loading of TRU-only FCM fuel into a pin without significant quantities of uranium challenges the design from the standpoint of several key reactivity parameters, particularly void reactivity, and to some degree, the Doppler coefficient. These unit cells, while providing an indication of how a whole core of similar fuel would behave, also provide information of how individual pins of TRU-only FCM fuel would influence the reactivity behavior of a heterogeneous assembly. If these FCM fuel pins are included in a heterogeneous assembly with LEU fuel pins, the overall reactivity behavior would be dominated by the uranium pins while attractive TRU destruction performance of the TRU-only FCM fuel pins may be preserved. A configuration such as this would be similar to CONFU assemblies analyzed in previous studies. Analogous to the plutonium content limits imposed on MOX fuel, some amount of TRU-only FCM pins in an otherwise-uranium fuel assembly may give acceptable reactivity

  13. Influence of the void fraction in the linear reactivity model; Influencia de la fraccion de vacios en el modelo de reactividad lineal

    Energy Technology Data Exchange (ETDEWEB)

    Castillo, J.A.; Ramirez, J.R.; Alonso, G. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)]. e-mail: jacm@nuclear.inin.mx

    2003-07-01

    The linear reactivity model allows the multicycle analysis in pressurized water reactors in a simple and quick way. In the case of the Boiling water reactors the void fraction it varies axially from 0% of voids in the inferior part of the fuel assemblies until approximately 70% of voids to the exit of the same ones. Due to this it is very important the determination of the average void fraction during different stages of the reactor operation to predict the burnt one appropriately of the same ones to inclination of the pattern of linear reactivity. In this work a pursuit is made of the profile of power for different steps of burnt of a typical operation cycle of a Boiling water reactor. Starting from these profiles it builds an algorithm that allows to determine the voids profile and this way to obtain the average value of the same one. The results are compared against those reported by the CM-PRESTO code that uses another method to carry out this calculation. Finally, the range in which is the average value of the void fraction during a typical cycle is determined and an estimate of the impact that it would have the use of this value in the prediction of the reactivity produced by the fuel assemblies is made. (Author)

  14. Collapse and coalescence of spherical voids subject to intense shearing: studied in full 3D

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau; Dahl, Jonas; Tvergaard, Viggo

    2012-01-01

    Micro-mechanical 2D cell model studies have revealed ductile failure during intense shearing to be governed by the interaction of neighbouring voids, which collapse to micro-cracks and continuously rotate and elongate until coalescence occurs. For a three-dimensional void structure, this implies...... significant straining of the matrix material located on the axis of rotation. In particular, the void surface material is severely deformed during shearing and void surface contact is established early in the deformation process. This 3D effect intensifies with decreasing stress triaxiality and complicates...... shape, void orientation etc. The objective of this work is to expand the range of stress triaxiality usually faced in 3D cell model studies, such that intense shearing is covered, and to bring forward details on the porosity and void shape evolution. The overall material response is presented...

  15. Experimental Study on Voided Reinforced Concrete Beams with Polythene Balls

    Science.gov (United States)

    Sivaneshan, P.; Harishankar, S.

    2017-07-01

    The primary component in any structure is concrete, that exist in buildings and bridges. In present situation, a serious problems faced by construction industry is exhaustive use of raw materials. Recent times, various methods are being adopted to limit the use of concrete. In structural elements like beams, polythene balls can be induced to reduce the usage of concrete. A simply supported reinforced concrete beam has two zones, one above neutral axis and other below neutral axis. The region below neutral axis is in tension and above neutral axis is in compression. As concrete is weak in tension, steel reinforcements are provided in tension zone. The concrete below the neutral axis acts as a stress transfer medium between the compression zone and tension zone. The concrete above the neutral axis takes minimum stress so that we could partially replace the concrete above neutral axis by creating air voids using recycled polythene balls. Polythene balls of varying diameters of 75 mm, 65 mm and 35 mm were partially replaced in compression zone. Hence the usage of concrete in beams and self-weight of the beams got reduced considerably. The Load carrying capacity, Deflection of beams and crack patterns were studied and compared with conventional reinforced concrete beams.

  16. An epidemiologic study of voiding and bowel habits in Korean children: a nationwide multicenter study.

    Science.gov (United States)

    Chung, Jae Min; Lee, Sang Don; Kang, Dong Ii; Kwon, Dong Deuk; Kim, Kun Suk; Kim, Su Yung; Kim, Han Gwun; Moon, Du Geon; Park, Kwan Hyun; Park, Yong Hyun; Pai, Ki Soo; Suh, Hong Jin; Lee, Jung Won; Cho, Won Yeol; Ha, Tae Sun; Han, Sang Won

    2010-07-01

    To evaluate the prevalence of abnormal voiding and bowel habits in healthy children, and to identify possible relationships between personal and familial factors and voiding and/or bowel habits. A randomly selected cross-sectional study was conducted in 19,240 children (5-13 years old) nationwide in the Republic of Korea. Parents were asked to complete questionnaires, which included items about nocturnal enuresis, daytime dysfunctional voiding symptoms (DVSs), and abnormal bowel habits (ABHs). Rates and associated factors were investigated. The overall rates of DVS, ABH, and of both were 46.4%, 31.3%, and 18.4%, respectively, and nocturnal enuresis was reported in 919 (5.6%). Daytime dysfunctional voiding symptoms were as follows: increased voiding frequency in 419 (2.5%), decreased voiding frequency in 720 (4.4%), urgency in 2740 (16.6%), daytime incontinence in 1854 (11.2%), urge incontinence in 2775 (16.8%), and holding maneuvers or postponed voiding in 3888 (23.5%). ABHs were as follows: constipation by frequency in 1103 (6.7%), constipation by the Bristol scale in 1941 (11.8%), fecal incontinence in 1293 (7.8%), and difficult or painful defecation in 2609 (15.8%). Delayed stool control, history of urinary tract infection, and a double-income family were positively associated with DVS or ABH or both. Furthermore, fathers with a low level of education and a low income were found to be associated with higher risk of ABH or DVS or both. Delayed stool control, a history of urinary tract infection, a low paternal level of education, a double-income family, and a lower family income had a negative effect on voiding or bowel habits in children. Copyright 2010 Elsevier Inc. All rights reserved.

  17. Cure Cycle Design Methodology for Fabricating Reactive Resin Matrix Fiber Reinforced Composites: A Protocol for Producing Void-free Quality Laminates

    Science.gov (United States)

    Hou, Tan-Hung

    2014-01-01

    For the fabrication of resin matrix fiber reinforced composite laminates, a workable cure cycle (i.e., temperature and pressure profiles as a function of processing time) is needed and is critical for achieving void-free laminate consolidation. Design of such a cure cycle is not trivial, especially when dealing with reactive matrix resins. An empirical "trial and error" approach has been used as common practice in the composite industry. Such an approach is not only costly, but also ineffective at establishing the optimal processing conditions for a specific resin/fiber composite system. In this report, a rational "processing science" based approach is established, and a universal cure cycle design protocol is proposed. Following this protocol, a workable and optimal cure cycle can be readily and rationally designed for most reactive resin systems in a cost effective way. This design protocol has been validated through experimental studies of several reactive polyimide composites for a wide spectrum of usage that has been documented in the previous publications.

  18. Void probability as a function of the void's shape and scale-invariant models. [in studies of spacial galactic distribution

    Science.gov (United States)

    Elizalde, E.; Gaztanaga, E.

    1992-01-01

    The dependence of counts in cells on the shape of the cell for the large scale galaxy distribution is studied. A very concrete prediction can be done concerning the void distribution for scale invariant models. The prediction is tested on a sample of the CfA catalog, and good agreement is found. It is observed that the probability of a cell to be occupied is bigger for some elongated cells. A phenomenological scale invariant model for the observed distribution of the counts in cells, an extension of the negative binomial distribution, is presented in order to illustrate how this dependence can be quantitatively determined. An original, intuitive derivation of this model is presented.

  19. Study of galaxies in the Lynx-Cancer void - I. Sample description

    Science.gov (United States)

    Pustilnik, S. A.; Tepliakova, A. L.

    2011-08-01

    The evolution of galaxies is influenced by the environment in which they reside. This effect should be strongest for the lowest-mass and -luminosity galaxies. To study dwarf galaxies in extremely low density environments, we have compiled a deep catalogue of dwarf galaxies in the nearby Lynx-Cancer void. This void hosts some of the most metal-poor dwarfs known to date. It borders the Local Volume at negative supergalactic Z(SGZ) coordinates and has a size of more than 16 Mpc. With a distance to its centre of only 18 Mpc, it is close enough to allow a search for the faintest dwarfs. Within the void 75 dwarf (-11.9 > MB > -18.0) and four subluminous (-18.0 > MB > -18.4) galaxies have been identified. We present the parameters of the void galaxies and a detailed analysis of the completeness of the catalogue as a function of magnitude and surface brightness. The catalogue appears almost complete to MB < -14 mag, but misses part of the fainter low surface brightness (LSB) face-on galaxies. This sample of void galaxies builds the basis of forthcoming observational studies that will provide insight into the main stellar population, H I mass-to-light ratio, metallicity and age for comparison with dwarfs in higher density regions. We briefly summarize the information on the unusual objects in the void and conclude that their concentration hints that voids are environments that are favourable for finding and studying unevolved dwarf galaxies.

  20. Experimental Studies on Void Detection in Concrete-filled Steel Tubes using Ultrasound

    OpenAIRE

    Dong, W; Wu, Z; Zhou, X; Tan, Y

    2016-01-01

    Due to shrinkage and/or inadequate compaction during concreting, voids may develop in a concrete-filled steel tube (CFST) between the concrete core and outer steel tube, which reduce the confinement effect of the steel tube on the concrete core, and further, decrease the load-carrying capacity and ductility of a CFST. In this study, an ultrasonic technique is utilized for quantifying voids in CFSTs by analyzing the ultrasound travel time in them. Four potential travel paths are identified in ...

  1. Comparison of MCNP4B and WIMS-AECL calculations of coolant-void-reactivity effects for uniform lattices of CANDU fuel

    Energy Technology Data Exchange (ETDEWEB)

    Kozier, K.S

    1999-05-01

    This paper compares the results of coolant-void reactivity (CVR) reactor-physics calculations performed using the Monte Carlo N-particle transport code, MCNP version 4B, with those obtained using Atomic Energy of Canada Limited's (AECL's) latest version of the Winfrith improved multigroup scheme (WIMS) code, WIMS-AECL version 2-5c. Cross sections derived from the evaluated nuclear data file version B-VI (ENDF/B-VI) are used for both the WIMS-AECL and MCNP4B calculations. The comparison is made for uniform lattices at room temperature containing either fresh natural uranium or mixed oxide (MOX) 37-element CANDU fuel. The MOX fuel composition corresponds roughly to that of irradiated CANDU fuel at a burnup of about 4500 MWd/tU. The level of agreement between the CVR predictions of WIMS-AECL and MCNP4B is studied as a function of lattice buckling (a measure of the curvature of the neutron-flux distribution) over the range from 0.0 to 4.1 m{sup -2} . For the cases studied, it is found that the absolute k values calculated by WIMS-AECL are higher than those of MCNP4B by several mk (1 mk is a change of 0.001 in k), amounts that depend on the fuel type being modelled and the particular cross-section data used. However, the agreement between WIMS-AECL and MCNP4B is much better for the CVR (i.e., the {delta}k on coolant voiding), and is relatively insensitive to the fuel type. (author)

  2. The sparkling Universe: clustering of voids and void clumps

    Science.gov (United States)

    Lares, Marcelo; Ruiz, Andrés N.; Luparello, Heliana E.; Ceccarelli, Laura; Garcia Lambas, Diego; Paz, Dante J.

    2017-07-01

    We analyse the clustering of cosmic voids using a numerical simulation and the main galaxy sample from the Sloan Digital Sky Survey. We take into account the classification of voids into two types that resemble different evolutionary modes: those with a rising integrated density profile (void-in-void mode or R-type) and voids with shells (void-in-cloud mode or S-type). The results show that voids of the same type have stronger clustering than the full sample. We use the correlation analysis to define void clumps, associations with at least two voids separated by a distance of at most the mean void separation. In order to study the spatial configuration of void clumps, we compute the minimal spanning tree and analyse their multiplicity, maximum length and elongation parameter. We further study the dynamics of the smaller sphere that enclose all the voids in each clump. Although the global densities of void clumps are different according to their member-void types, the bulk motions of these spheres are remarkably lower than those of randomly placed spheres with the same radius distribution. In addition, the coherence of pairwise void motions does not strongly depend on whether voids belong to the same clump. Void clumps are useful to analyse the large-scale flows around voids, since voids embedded in large underdense regions are mostly in the void-in-void regime, where the expansion of the larger region produces the separation of voids. Similarly, voids around overdense regions form clumps that are in collapse, as reflected in the relative velocities of voids that are mostly approaching.

  3. Study on the formation of micro-voids during ductile fracture

    Science.gov (United States)

    Long, Shao-Lei; Liang, Yi-Long; Lu, Ye-Mao; Yang, Ming; Yin, Cun-Hong

    2018-01-01

    In this work, the formation of micro-voids for ductile fracture has been discussed with regards to the classical nucleation theory from the phase transformation in 20CrNi2Mo steel. The differences in them were determined based upon the driving force and the resistance. In terms of tensile load, the driving force was the energy of tensile load before necking, while the resistance was the surface energy from the formation of mass of micro-voids, as determined by the fracture toughness instead of the phase transformation. Finally, the relationship between the formation of micro-voids and the macroscopic properties was discussed. The results illustrated that the formation of micro-voids depended on the elastic-plastic energy and on the yield strength represented by r* (the critical formation radius) and {{Δ }}{G}* (the critical formation energy). These results were confirmed from r 1* (with the experiment) and r 2* (with the calculation). The work provided a novel way to study the relationship of micro-parameters and macro-properties. In addition, it was found that the critical formation diameter (2r*) of micro-voids was close to the width of martensite lath (d l).

  4. A reliability study on tin based lead free micro joint including intermetallic and void evolution

    Science.gov (United States)

    Feyissa, Frezer Assefa

    In microelectronics soldering to Cu pad lead to formation of two intermetallic structures in the solder -pad interface. The growth of these layers is accompanied by microscopic voids that usually cause reliability concern in the industry. Therefore it is important to understand factors that contribute for the growth of IMC using various combination of reflow time, Sn thickness and aging temperature. Systematic study was conducted on Cu-Sn system to investigate the formation and growth of intermetallic compound (IMC) as well as voiding evolution for different solder thicknesses. The growth of the Cu6Sn5 IMC layer was found to be increasing as the Sn thicknesses increase after reflow while the Cu3Sn layer were decreasing under same conditions. Also after reflow and aging more voiding were shown to occur in the thin solder than thicker one.

  5. [Serial voiding urosonography: a safe technique for the study of the entire urinary tract in children].

    Science.gov (United States)

    Duran, C; del Riego, J; Riera, L

    2013-01-01

    For more than a decade, serial voiding urosonography has been one of the imaging modalities used to detect vesicoureteral reflux in children and it is now also used to study the urethra. The main advantage of this technique is it does not irradiate. Given the important recognition of serial voiding urosonography by the European Society of Pediatric Radiology at the last congress in May 2011, we think it is useful to describe how to carry out this technique successfully. In this update on serial voiding urosonography, we describe the indications, the entire procedure, and the different characteristics of this technique, which we understand will soon become the technique of choice for screening for vesicoureteral reflux as well as for urethral pathology in children. Copyright © 2011 SERAM. Published by Elsevier Espana. All rights reserved.

  6. Parents Function and Behavioral Disorders in Children with and without Diurnal Voiding Dysfunction: A Comparative Study

    Directory of Open Access Journals (Sweden)

    Parsa Yousefi

    2014-09-01

    Full Text Available Background: Diurnal voiding dysfunction is one of the most common causes of pediatric urology clinic admissions. It can cause behavioral problems for children and their parents. We lunch this study to compare the parents’ function and children’s behavior problem in pediatric patients suffering from diurnal voiding dysfunction referring Arak Amir Kabir hospital. Materials and Methods: To perform this case-control study, we recruit 116 children with diurnal voiding dysfunction and compared them with other 116 children non-affected children aged between 5 to 16 years old. The child behavior checklist (CBCL4/18 for children behavior assessment and Global Assessment of Functioning (GAF for the evaluation of their parent’s behavior was completed by the parents. Data was analyzed using ANOVA, qualitative variables and χ2 formula. Results: Among 116 patient with voiding dysfunction, 10 case (8.6% showed behavioral problem while this figure was 3 case (2.6% in the control group, denoting a significant difference (p=0.04. Moreover 20 children (17.2% in the case group and 9 children (7.8% in the control group had internalizing problem (p=0.02. Twenty two children (19% with voiding dysfunction and 8 children (6.9% in the healthy group had externalizing problem which was also a significant difference (p=0.01. As a significant difference (0.01, the parent’s average stress and behavior scores in case and control group were 3.65 and 3.76, respectively. Conclusion: The higher prevalence of behavioral problem in the children suffering from diurnal voiding dysfunction and their parent’s functional impairment highlights the importance of early parent’s intervention for early treatment and subsequently prevention of future behavioral problem in their sibling.

  7. Emerging Economies, Institutional Voids, and Innovation Drivers : A Study in India

    NARCIS (Netherlands)

    Voeten, Jaap; Saiyed, Abrar Ali; Dutta, Dev K.

    Research has highlighted the importance of the institutional context on innovation and entrepreneurship. The focus of this qualitative research was to study small and medium enterprises (SMEs) in the manufacturing sector in India with the purpose of understanding how institutional voids affect the

  8. Comparative sodium void effects for different advanced liquid metal reactor fuel and core designs

    Energy Technology Data Exchange (ETDEWEB)

    Dobbin, K.D.; Kessler, S.F.; Nelson, J.V.; Gedeon, S.R.; Omberg, R.P.

    1991-07-01

    An analysis of metal-, oxide, and nitride-fueled advanced liquid metal reactor cores was performed to investigate the calculated differences in sodium void reactivity, and to determine the relationship between sodium void reactivity and burnup reactivity swing using the three fuel types. The results of this analysis indicate that nitride fuel has the least positive sodium void reactivity for any given burnup reactivity swing. Thus, it appears that a good design compromise between transient overpower and loss of flow response is obtained using nitride fuel. Additional studies were made to understand these and other nitride advantages. 8 refs., 5 figs., 3 tabs.

  9. Study of galaxies in the Lynx-Cancer void. IV. Photometric properties

    Science.gov (United States)

    Perepelitsyna, Yu. A.; Pustilnik, S. A.; Kniazev, A. Yu.

    We present the results of a photometric study of 85 objects from the updated sample of galaxies residing in the nearby Lynx--Cancer void. We perform our photometry on u, g, r, and i-band images of the Sloan Digital Sky Survey. We determine model-independent galaxy parameters such as the integrated magnitudes and colors, effective radii and the corresponding surface brightness values, optical radii and Holmberg radii. We analyze the radial surface brightness profiles to determine the central brightness values and scale lengths of the model discs. We analyze the colors of the outer parts of the galaxies and compare them with model evolutionary tracks computed using the PEGASE2 software package. This allowed us to estimate the time T_SF elapsed since the onset of star formation, which turned out to be on the order of the cosmological time T_0 for the overwhelming majority of the galaxies studied. However, for 13 galaxies of the sample the time T_SF does not exceed T_0/2 ~ 7 Gyr, and for 7 of them T_SF -13.2. We use the integrated magnitudes and colors to estimate the stellar masses of the galaxies. We estimate the parameter M(HI)/L_B and the gas mass fractions for void galaxies with known HI-line fluxes. A small subgroup (about 10%) of the gas-richest void galaxies with M(HI)/L_B > 2.5 has gas mass fractions that reach 94-99%. The outer regions of many of these galaxies show atypically blue colors. To test various statistical differences between void galaxies and galaxies from the samples selected using more general criteria, we compare some of the parameters of void galaxies with similar data for the sample of 195 galaxies from the Equatorial Survey (ES) based on a part of the HIPASS blind HI survey. abridged

  10. A comparative study of voiding in rat and guinea pig: simultaneous measurement of flow rate and pressure

    NARCIS (Netherlands)

    E. van Asselt (Els); J.M. Groen (Jan); R. van Mastrigt (Ron)

    1995-01-01

    textabstractIn this study, the voiding phase of the micturition cycle in the anesthetized rat and guinea pig is analyzed. In both animals, voiding is characterized by an increase in intravesical pressure and then a decrease, which is accompanied by flow through the urethra and emission of urine. An

  11. The relevance of urodynamic studies for Urge syndrome and dysfunctional voiding: a multicenter controlled trial in children.

    Science.gov (United States)

    Bael, An; Lax, Hildegard; de Jong, Tom P V M; Hoebeke, Piet; Nijman, Rien J M; Sixt, Rune; Verhulst, John; Hirche, Herbert; van Gool, Jan D

    2008-10-01

    The objective of this study was to compare prospectively, in urge syndrome and dysfunctional voiding, clinical patterns with urodynamic patterns, to assess changes in urodynamic patterns after treatment, and to correlate urodynamic patterns and parameters with treatment outcome. In the European Bladder Dysfunction Study 97 children with clinically diagnosed urge syndrome received standard treatment, to which was randomly added placebo, oxybutynin or bladder training with online feedback. In a separate branch 105 children with clinically diagnosed dysfunctional voiding were randomly allocated to standard treatment or standard treatment plus pelvic floor training with online feedback. In all children urodynamic studies were performed before and immediately after treatment. In urge syndrome detrusor overactivity was present in 33% of cases before and 27% after treatment (of which 65% were de novo). Detrusor overactivity did not correlate with treatment outcome. In dysfunctional voiding increased pelvic floor activity during voiding, which was present in 67% of cases before and 56% after treatment (of which 45% were de novo), did not correlate with treatment outcome. In urge syndrome as well as in dysfunctional voiding neither maximum detrusor pressure during voiding, cystometric bladder capacity, bladder compliance nor free flow patterns correlated with treatment outcome. Neither detrusor overactivity nor increased pelvic floor activity during voiding correlated with treatment outcome. Standard treatment could be the first choice in urge syndrome as well as in dysfunctional voiding, reserving urodynamic studies for patients in whom this first approach fails.

  12. Feasibility Study of In-situ Characterization of Size Distribution of Air Voids in Concrete Pavements

    OpenAIRE

    Li, Kai Ming; Tong, Bao N; Liu, Sheng

    2013-01-01

    This report concerns a feasibility study on the use of a non-destructive and non-invasive method to determine the size distribution of air voids in fresh concrete, which will be used for laying concrete pavement. A preliminary review of different techniques suggested that the measurement of the p-wave velocity of ultrasound pulses transmitted through a fresh concrete specimen offers the most straightforward approach. This report describes an experimental study to address the design of an expe...

  13. Sedation with midazolam for voiding cystourethrography in children: a randomised double-blind study

    Energy Technology Data Exchange (ETDEWEB)

    Stokland, E.; Jacobsson, B.; Ljung, B. [Dept. of Paediatric Radiology and Clinical Physiology, The Queen Silvia Children' s Hospital, Gothenburg (Sweden); Andreasson, S. [Dept. of Paediatric Anaesthesiology, The Queen Silvia Children' s Hospital, Gothenburg (Sweden); Jodal, U. [Dept. of Paediatrics, The Queen Silvia Children' s Hospital, Gothenburg (Sweden)

    2003-04-01

    Background: Sedation with midazolam facilitates the performance of diagnostic procedures in children, including voiding cystourethrography (VCUG). However, the influence of sedation on voiding and imaging results have not been adequately evaluated. Objective: Midazolam and placebo were compared to assess discomfort during VCUG and to evaluate if sedation influenced the outcome of the examination. Materials and methods: The study was prospective, randomized and double-blind, and included 95 children, 48 in the midazolam group (median age 2.2 years) and 47 in the placebo group (median age 3.2 years). The evaluation included the child's/parent's experience of the VCUG, as well as the examination results. Results: The children/parents in the midazolam group experienced the VCUG as less distressing compared to those in the placebo group (P < 0.001). Forty-six of 48 children sedated with midazolam could void during the imaging procedure compared to 38 of 47 children given placebo (NS). There was no difference in frequency or grade of vesicoureteric reflux or bladder emptying between the groups. Conclusions: When sedation is required to perform VCUG in children, midazolam can be used without negative effect on the outcome of the examination. (orig.)

  14. Voiding dysfunction in children. Pelvic-floor exercises or biofeedback therapy: a randomized study.

    Science.gov (United States)

    Vasconcelos, Mônica; Lima, Eleonora; Caiafa, Letícia; Noronha, Alessandra; Cangussu, Renata; Gomes, Suzely; Freire, Raquel; Filgueiras, Maria Teresa; Araújo, Junia; Magnus, Gisele; Cunha, Cláudia; Colozimo, Enrico

    2006-12-01

    Fifty-six patients 5.9-15.2 years old with dysfunctional elimination syndrome (DES) unimproved by previous therapies were randomly distributed into two voiding training programs: group 1 contained 26 patients submitted to 24 training sessions over a 3-month period; group 2 contained 30 patients submitted to 16 sessions over a 2-month period. Both groups adhered to a voiding and drinking schedule, received instruction on adequate toilet posture, were reinforced through the maintenance of voiding diaries, and went through proprioceptive and pelvic floor muscle training (Kegel exercises). Group 2 patients also received biofeedback therapy. Clinical evaluation was carried out before each program's initiation and 1, 6, and 12 months after each program's termination. All patients were submitted to renal ultrasonography and dynamic ultrasonography before and 6 months after each program's conclusion. Millivoltage recordings of pelvic floor muscles were compared before and after training. Urinary continence was improved after completion of either training program. Only those patients who received biofeedback training showed a significant decrease in postvoiding residual (PVR) urine as detected by dynamic ultrasonography. Our results show that either training regime can reduce episodic urinary incontinence and urinary tract infection but that further study is required to identify the optimal training duration.

  15. Effect of stress-triaxiality on void growth in dynamic fracture of metals: a molecular dynamics study

    Energy Technology Data Exchange (ETDEWEB)

    Seppala, E T; Belak, J; Rudd, R E

    2003-10-07

    The effect of stress-triaxiality on growth of a void in a three dimensional single-crystal face-centered-cubic (FCC) lattice has been studied. Molecular dynamics (MD) simulations using an embedded-atom (EAM) potential for copper have been performed at room temperature and using strain controlling with high strain rates ranging from 10{sup 7}/sec to 10{sup 10}/sec. Strain-rates of these magnitudes can be studied experimentally, e.g. using shock waves induced by laser ablation. Void growth has been simulated in three different conditions, namely uniaxial, biaxial, and triaxial expansion. The response of the system in the three cases have been compared in terms of the void growth rate, the detailed void shape evolution, and the stress-strain behavior including the development of plastic strain. Also macroscopic observables as plastic work and porosity have been computed from the atomistic level. The stress thresholds for void growth are found to be comparable with spall strength values determined by dynamic fracture experiments. The conventional macroscopic assumption that the mean plastic strain results from the growth of the void is validated. The evolution of the system in the uniaxial case is found to exhibit four different regimes: elastic expansion; plastic yielding, when the mean stress is nearly constant, but the stress-triaxiality increases rapidly together with exponential growth of the void; saturation of the stress-triaxiality; and finally the failure.

  16. Study of galaxies in the Lynx-Cancer void. II. Element abundances

    Science.gov (United States)

    Pustilnik, S. A.; Tepliakova, A. L.; Kniazev, A. Yu.

    2011-07-01

    In the framework of study of the evolutionary status of galaxies in the nearby Lynx-Cancer void, we present the results of the SAO RAS 6-m telescope spectroscopy for 20 objects in this region. The principal faint line [O iii]λ4363 Å, used to determine the electron temperature and oxygen abundance (O/H) by the classicalmethod, is clearly detected in only about 2/3 of the studied objects. For the remaining galaxies this line is either faint or undetected. To obtain the oxygen abundances in these galaxies we as well apply the semi-empirical method by Izotov and Thuan, and/or the empirical methods of Pilyugin et al., which are only employing the intensities of sufficiently strong lines. We also present our O/H measurements for 22 Lynx-Cancer void galaxies, for which the suitable Sloan Digital Sky Survey (SDSS) spectra are available. In total, we present the combined O/H data for 48 Lynx-Cancer void galaxies, including the data adopted from the literature and our own earlier results. We make a comparison of their locations on the (O/H)-MB diagram with those of the dwarf galaxies of the Local Volume in the regions with denser environment. We infer that the majority of galaxies from this void on the average reveal an about 30% lower metallicity. In addition, a substantial fraction (not less than 10%) of the void dwarf galaxies have a much larger O/H deficiency (up to a factor of 5). Most of them belong to the tiny group of objects with the gas metallicity Z

  17. A molecular dynamics study of void initiation and growth in monocrystalline and nanocrystalline copper

    OpenAIRE

    Traiviratana, Sirirat

    2008-01-01

    MD simulations in monocrystalline and nanocrystalline copper were carried out with LAMMPS to reveal void growth mechanisms. The specimens were subjected to both tensile uniaxial and hydrostatic strains; the results confirm that the emission of (shear) loops is the primary mechanism of void growth. The expansion of the loops and their cross slip leads to the severely work hardened layer surrounding a growing void. Calculations were carried out on voids with different sizes, and a size dependen...

  18. Void shape effects and voids starting from cracked inclusion

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2011-01-01

    to 10−10, which means that the metal undergoes huge strains before coalescence. This is accounted for in the present analyses by using remeshing techniques. The evolution of the void shape during the large deformations is a natural outcome of the numerical analysis. Also the effect of different initial...... second phase particle. As the particle deforms relatively little the void growth is here dominated by strong blunting of the metal at the tip of the initial penny-shaped crack. These analyses are used to estimate how well the void shape evolution would be approximated by assuming that the presence...... void shapes is considered, as well as the effect of different spacings between the voids in the axial and transverse directions. While these first analyses are carried out for voids in a homogeneous metal, a second set of cell model studies are carried out for voids that initiate from a crack in a hard...

  19. Performance of Transuranic-Loaded Fully Ceramic Micro-Encapsulated Fuel in LWRs Final Report, Including Void Reactivity Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Michael A. Pope; R. Sonat Sen; Brian Boer; Abderrafi M. Ougouag; Gilles Youinou

    2011-09-01

    The current focus of the Deep Burn Project is on once-through burning of transuranics (TRU) in light-water reactors (LWRs). The fuel form is called Fully-Ceramic Micro-encapsulated (FCM) fuel, a concept that borrows the tri-isotropic (TRISO) fuel particle design from high-temperature reactor technology. In the Deep Burn LWR (DB-LWR) concept, these fuel particles are pressed into compacts using SiC matrix material and loaded into fuel pins for use in conventional LWRs. The TRU loading comes from the spent fuel of a conventional LWR after 5 years of cooling. Unit cell and assembly calculations have been performed using the DRAGON-4 code to assess the physics attributes of TRU-only FCM fuel in an LWR lattice. Depletion calculations assuming an infinite lattice condition were performed with calculations of various reactivity coefficients performed at each step. Unit cells and assemblies containing typical UO2 and mixed oxide (MOX) fuel were analyzed in the same way to provide a baseline against which to compare the TRU-only FCM fuel. Then, assembly calculations were performed evaluating the performance of heterogeneous arrangements of TRU-only FCM fuel pins along with UO2 pins.

  20. A molecular dynamics study of void initiation and growth in monocrystalline and nanocrystalline copper

    Science.gov (United States)

    Traiviratana, Sirirat

    MD simulations in monocrystalline and nanocrystalline copper were carried out with LAMMPS to reveal void growth mechanisms. The specimens were subjected to both tensile uniaxial and hydrostatic strains; the results confirm that the emission of (shear) loops is the primary mechanism of void growth. The expansion of the loops and their cross slip leads to the severely work hardened layer surrounding a growing void. Calculations were carried out on voids with different sizes, and a size dependence of the stress response to emitted dislocations was observed, in disagreement with the Gurson model [1] which is scale independent. The growth of voids simulated by MD is compared with the Cocks-Ashby constitutive model and significant agreement is found. The density of geometrically-necessary dislocations as a function of void size is calculated based on the emission of shear loops and their outward propagation. Calculations were also carried out for a void at the interface between two grains sharing a tilt boundary. The results show similar dislocation behaviors. A code that uses Voronoi tessellation for constructing nanocrystalline structures was developed and used to prepare the structures for simulations. Nanocrystal simulations reveal grain sliding and grain rotation as the nanocrystal deformed. Voids were nucleated at grain junctions and grew to coalescence as dislocations accommodated the material transfer. A code that can be used during post-processing to extract useful dislocation information from MD simulation data was partially developed and proved the feasibility of automatically analyzing dislocations.

  1. Studies of void growth in a thin ductile layer between ceramics

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    1997-01-01

    The growth of voids in a thin ductile layer between ceramics is analysed numerically, using an axisymmetric cell model to represent an array of uniformly distributed spherical voids at the central plane of the layer. The purpose is to determine the full traction-separation law relevant to crack...... growth by a ductile mechanism along the thin layer. Plastic flow in the layer is highly constrained by the ceramics, so that a high. level of triaxial tension develops, leading in some cases to cavitation instabilities. The computations are continued to a state near the occurrence of void coalescence....

  2. Interaction of very small voids with larger voids

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    1998-01-01

    For a very small void in the material between much larger voids the influence of local stress increases induced by the larger voids is studied numerically. The point of interest is whether or not such local stress increases result in a cavitation instability at the tiny void, even if the average ...... an important role. (C) 1998 Elsevier Science Ltd. All rights reserved....... the full 3D numerical problem. For overall stress levels as large as those reached ahead of a blunting crack tip, a cavitation instability at the small void, induced by interaction with the large voids, is not found here. But the results show that localization of plastic how in the unit cell plays...

  3. Home uroflowmetry biofeedback in behavioral training for dysfunctional voiding in school-age children: a randomized controlled study

    NARCIS (Netherlands)

    Klijn, Aart J.; Uiterwaal, Cuno S. P. M.; Vijverberg, Marianne A. W.; Winkler, Pauline L. H.; Dik, Pieter; de Jong, Tom P. V. M.

    2006-01-01

    We studied the added value of home uroflowmetry for biofeedback training compared to added attention and standard therapy in a multicomponent behavioral training program for voiding disorders in school-age children. Little is known about the role of biofeedback by home uroflowmetry for dysfunctional

  4. Reactive sites influence in PMMA oligomers reactivity: a DFT study

    Science.gov (United States)

    Paz, C. V.; Vásquez, S. R.; Flores, N.; García, L.; Rico, J. L.

    2018-01-01

    In this work, we present a theoretical study of methyl methacrylate (MMA) living anionic polymerization. The study was addressed to understanding two important experimental observations made for Michael Szwarc in 1956. The unexpected effect of reactive sites concentration in the propagation rate, and the self-killer behavior of MMA (deactivating of living anionic polymerization). The theoretical calculations were performed by density functional theory (DFT) to obtain the frontier molecular orbitals values. These values were used to calculate and analyze the chemical interaction descriptors in DFT-Koopmans’ theorem. As a result, it was observed that the longest chain-length species (related with low concentration of reactive sites) exhibit the highest reactivity (behavior associated with the increase of the propagation rate). The improvement in this reactivity was attributed to the crosslinking produced in the polymethyl methacrylate chains. Meanwhile, the self-killer behavior was associated with the intermolecular forces present in the reactive sites. This behavior was associated to an obstruction in solvation, since the active sites remained active through all propagation species. The theoretical results were in good agreement with the Szwarc experiments.

  5. Study of the Lynx-Cancer void galaxies. - V. The extremely isolated galaxy UGC 4722

    Science.gov (United States)

    Chengalur, J. N.; Pustilnik, S. A.; Makarov, D. I.; Perepelitsyna, Y. A.; Safonova, E. S.; Karachentsev, I. D.

    2015-04-01

    We present a detailed study of the extremely isolated Sdm galaxy UGC 4722 (MB = -17.4) located in the nearby Lynx-Cancer void. UGC 4722 is a member of the Catalogue of Isolated Galaxies, and has also been identified as one of the most isolated galaxies in the Local Supercluster. Optical images of the galaxy however show that it has a peculiar morphology with an elongated ˜14 kpc-long plume. New observations with the Russian 6-m telescope (BTA) and the Giant Metrewave Radio Telescope (GMRT) of the ionized and neutral gas in UGC 4722 reveal the second component responsible for the disturbed morphology of the system. This is a small, almost completely destroyed, very gas-rich dwarf (MB = -15.2, M(H I)/LB ˜ 4.3) We estimate the oxygen abundance for both galaxies to be 12 + log (O/H) ˜ 7.5-7.6 which is two to three times lower than what is expected from the luminosity-metallicity relation for similar galaxies in denser environments. The ugr colours of the plume derived from Sloan Digital Sky Survey (SDSS) images are consistent with a simple stellar population with a post starburst age of 0.45-0.5 Gyr. This system hence appears to be the first known case of a minor merger with a prominent tidal feature consisting of a young stellar population.

  6. Size effects on void growth in single crystals with distributed voids

    DEFF Research Database (Denmark)

    Borg, Ulrik; Niordson, Christian Frithiof; Kysar, J.W.

    2008-01-01

    The effect of void size on void growth in single crystals with uniformly distributed cylindrical voids is studied numerically using a finite deformation strain gradient crystal plasticity theory with an intrinsic length parameter. A plane strain cell model is analyzed for a single crystal...... with three in-plane slip systems. It is observed that small voids allow much larger overall stress levels than larger voids for all the stress triaxialities considered. The amount of void growth is found to be suppressed for smaller voids at low stress triaxialities. Significant differences are observed...

  7. On cavitation instabilities with interacting voids

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2012-01-01

    When a single void grows in an elastic–plastic material a cavitation instability may occur, if the stress triaxiality is sufficiently high. The effect of neighbouring voids on such unstable cavity growth is studied here by comparing two different models. The first model considers a periodic array...... voids so far apart that the radius of the plastic zone around each void is less than 1% of the current spacing between the voids, can still affect each others at the occurrence of a cavitation instability such that one void stops growing while the other grows in an unstable manner. On the other hand...

  8. The handling of urinary incontinence in Danish general practices after distribution of guidelines and voiding diary reimbursement: an observational study

    Directory of Open Access Journals (Sweden)

    Viktrup Lars

    2004-06-01

    Full Text Available Abstract Background Though urinary incontinence (UI is a bothersome condition for the individual patient, the patients tend not to inform their physician about UI and the physician tend not to ask the patient. Recently different initiatives have been established in Danish general practices to improve the management of UI. The aim of this study was to identify the handling of urinary incontinence (UI in Danish general practices after distribution of clinical guidelines and reimbursement for using a UI diary. Methods In October 2001, a questionnaire was sent to 243 general practitioners (GPs in Frederiksborg County following distribution of clinical guidelines in July 1999 (UI in general practice and September 2001 (UI in female, geriatric, or neurological patients. A policy for a small reimbursement to GPs for use of a fluid intake/voiding diary in the assessment of UI in general practice was implemented in October 2001. Information concerning monthly reimbursement for using a voiding diary, prescribed drugs (presumably used for treating UI, UI consultations in outpatient clinics, and patient reimbursement for pads was obtained from the National Health Service County Registry. Results Of the 132 (54% GPs who replied, 87% had read the guidelines distributed 2 years before, but only 47% used them daily. The majority (69% of the responding GPs had read and appreciated 1–3 other UI guidelines distributed before the study took place. Eighty-three percent of the responding GPs sometimes or often actively asked their patients about UI, and 92% sometimes or often included a voiding diary in the UI assessment. The available registry data concerning voiding diary reimbursement, prescribed UI drugs, UI consultations in outpatient clinics, and patient reimbursement for pads were insufficient or too variable to determine significant trends. Conclusion GPs management of UI in a Danish county may be reasonable, but low response rate to the questionnaire and

  9. Study of galaxies in the Lynx-Cancer void - VII. New oxygen abundances

    Science.gov (United States)

    Pustilnik, S. A.; Perepelitsyna, Y. A.; Kniazev, A. Y.

    2016-11-01

    We present new or improved oxygen abundances (O/H) for the nearby Lynx-Cancer void updated galaxy sample. They are obtained via the SAO 6-m telescope spectroscopy (25 objects), or derived from the Sloan Digital Sky Survey spectra (14 galaxies, of which for seven objects O/H values were unknown). For eight galaxies with detected [O III] λ4363 line, O/H values are derived via the direct (Te) method. For the remaining objects, O/H was estimated via semi-empirical and empirical methods. For all accumulated O/H data for 81 galaxies of this void (with 40 of them derived via Te method), their relation `O/H versus MB' is compared with that for similar late-type galaxies from denser environments (the Local Volume `reference sample'). We confirm our previous conclusion derived for a subsample of 48 objects: void galaxies show systematically reduced O/H for the same luminosity with respect to the reference sample, in average by 0.2 dex, or by a factor of ˜1.6. Moreover, we confirm the fraction of ˜20 per cent of strong outliers, with O/H of two to four times lower than the typical values for the `reference' sample. The new data are consistent with the conclusion on the slower evolution of the main void galaxy population. We obtained Hα velocity for the faint optical counterpart of the most gas-rich (M(H I)/LB = 25) void object J0723+3624, confirming its connection with the respective H I blob. For similar extremely gas-rich dwarf J0706+3020, we give a tentative O/H ˜(O/H)⊙/45. In Appendix A, we present the results of calibration of semi-empirical method by Izotov & Thuan and of empirical calibrators by Pilyugin & Thuan and Yin et al. on the sample of ˜150 galaxies from the literature with O/H measured by Te method.

  10. Void initiation from interfacial debonding of spherical silicon particles inside a silicon-copper nanocomposite: a molecular dynamics study

    Science.gov (United States)

    Cui, Yi; Chen, Zengtao

    2017-02-01

    Silicon particles with diameters from 1.9 nm to 30 nm are embedded in a face-centered-cubic copper matrix to form nanocomposite specimens for simulation. The interfacial debonding of silicon particles from the copper matrix and the subsequent growth of nucleated voids are studied via molecular dynamics (MD). The MD results are examined from several different perspectives. The overall mechanical performance is monitored by the average stress-strain response and the accumulated porosity. The ‘relatively farthest-traveled’ atoms are identified to characterize the onset of interfacial debonding. The relative displacement field is plotted to illustrate both subsequent interfacial debonding and the growth of a nucleated void facilitated by a dislocation network. Our results indicate that the initiation of interfacial debonding is due to the accumulated surface stress if the matrix is initially dislocation-free. However, pre-existing dislocations can make a considerable difference. In either case, the dislocation emission also contributes to the subsequent debonding process. As for the size effect, the debonding of relatively larger particles causes a drop in the stress-strain curve. The volume fraction of second-phase particles is found to be more influential than the size of the simulation box on the onset of interfacial debonding. The volume fraction of second-phase particles also affects the shape of the nucleated void and, therefore, influences the stress response of the composite.

  11. Titanium-Oxygen Reactivity Study

    Science.gov (United States)

    Chafey, J. E.; Scheck, W. G.; Witzell, W. E.

    1962-01-01

    A program has been conducted at Astronautics to investigate the likelihood of occurrence of the catastrophic oxidation of titanium alloy sheet under conditions which simulate certain cases of accidental failure of the metal while it is in contact with liquid or gaseous oxygen. Three methods of fracturing the metal were used; they consisted of mechanical puncture, tensile fracture of welded joints, and perforation by very high velocity particles. The results of the tests which have been conducted provide further evidence of the reactivity of titanium with liquid and gaseous oxygen. The evidence indicates that the rapid fracturing of titanium sheet while it is in contact with oxygen initiates the catastrophic oxidation reaction. Initiation occurred when the speed of the fracture was some few feet per second, as in both the drop-weight puncture tests and the static tensile fracture tests of welded joints, as well as when the speed was several thousand feet per second, as in the simulated micrometeoroid penetration tests. The slow propagation of a crack, however, did not initiate the reaction. It may logically be concluded that the localized frictional heat of rapid fracture and/or spontaneous oxidation (exothermic) of minute particles emanating from the fracture cause initiation of the reaction. Under conditions of slow fracture, however, the small heat generated may be adequately dissipated and the reaction is not initiated. A portion of the study conducted consisted of investigating various means by which the reaction might be retarded or prevented. Providing a "barrier" at the titanium-oxygen interface consisting of either aluminum metal or a coating of a petroleum base corrosion inhibitor appeared to be only partially effective in retarding the reaction. The accidental puncturing or similar rupturing of thin-walled pressurized oxygen tanks on missiles and space vehicle will usually constitute loss of function, and may sometimes cause their catastrophic destruction

  12. Phase-field study on geometry-dependent migration behavior of voids under temperature gradient in UO2 crystal matrix

    Science.gov (United States)

    Chen, Weijin; Peng, Yuyi; Li, Xu'an; Chen, Kelang; Ma, Jun; Wei, Lingfeng; Wang, Biao; Zheng, Yue

    2017-10-01

    In this work, a phase-field model is established to capture the void migration behavior under a temperature gradient within a crystal matrix, with an appropriate consideration of the surface diffusion mechanism and the vapor transport mechanism. The interfacial energy and the coupling between the vacancy concentration field and the crystal order parameter field are carefully modeled. Simulations are performed on UO2. The result shows that for small voids (with an area ≤ πμm2), the well-known characteristics of void migration, in consistence with the analytical model, can be recovered. The migration is manifested by a constant velocity and a minor change of the void shape. In contrast, for large voids (with an area of ˜10 μm2) initially in circular shapes, significant deformation of the void from a circular to cashew-like shape is observed. After long-time migration, the deformed void would split into smaller voids. The size-dependent behavior of void migration is due to the combined effect of the interfacial energy (which tends to keep the void in circular shape) and the surface diffusion flow (which tends to deform the void due to the nonuniform diffusion along the surface). Moreover, the initial shape of the void modifies the migration velocity and the time point when splitting occurs (for large voids) at the beginning of migration due to the shape relaxation of the void. However, it has a minor effect on the long-time migration. Our work reveals novel void migration behaviors in conditions where the surface-diffusion mechanism is dominant over the vapor transport mechanism; meanwhile, the size of the void lies at a mediate size range.

  13. Tracing the gravitational potential using cosmic voids

    Science.gov (United States)

    Nadathur, Seshadri; Hotchkiss, Shaun; Crittenden, Robert

    2017-06-01

    The properties of large underdensities in the distribution of galaxies in the Universe, known as cosmic voids, are potentially sensitive probes of fundamental physics. We use data from the MultiDark suite of N-body simulations and multiple halo occupation distribution mocks to study the relationship between galaxy voids, identified using a watershed void-finding algorithm, and the gravitational potential Φ. We find that the majority of galaxy voids correspond to local density minima in larger scale overdensities, and thus lie in potential wells. However, a subset of voids can be identified that closely trace maxima of the gravitational potential and thus stationary points of the velocity field. We identify a new void observable, λv, which depends on a combination of the void size and the average galaxy density contrast within the void, and show that it provides a good proxy indicator of the potential at the void location. A simple linear scaling of Φ as a function of λv is found to hold, independent of the redshift and properties of the galaxies used as tracers of voids. We provide an accurate fitting formula to describe the spherically averaged potential profile Φ(r) about void centre locations. We discuss the importance of these results for the understanding of the evolution history of voids, and for their use in precision measurements of the integrated Sachs-Wolfe effect, gravitational lensing and peculiar velocity distortions in redshift space.

  14. Partial discharges in spheroidal voids: Void orientation

    DEFF Research Database (Denmark)

    McAllister, Iain Wilson

    1997-01-01

    Partial discharge transients can be described in terms of the charge induced on the detecting electrode. The influence of the void parameters upon the induced charge is examined and discussed for spheroidal voids. It is shown that a quantitative interpretation of the induced charge requires...

  15. Archaeology of Void Spaces

    Science.gov (United States)

    Look, Cory

    The overall goal of this research is to evaluate the efficacy of pXRF for the identification of ancient activity areas at Pre-Columbian sites in Antigua that range across time periods, geographic regions, site types with a variety of features, and various states of preservation. These findings have important implications for identifying and reconstructing places full of human activity but void of material remains. A synthesis for an archaeology of void spaces requires the construction of new ways of testing anthrosols, and identifying elemental patterns that can be used to connect people with their places and objects. This research begins with an exploration of rich middens in order to study void spaces. Midden archaeology has been a central focus in Caribbean research, and consists of an accumulation of discarded remnants from past human activities that can be tested against anthrosols. The archaeological collections visited for this research project involved creating new databases to generate a comprehensive inventory of sites, materials excavated, and assemblages available for study. Of the more than 129 Pre-Columbian sites documented in Antigua, few sites have been thoroughly surveyed or excavated. Twelve Pre-Columbian sites, consisting of thirty-six excavated units were selected for study; all of which contained complete assemblages for comparison and soil samples for testing. These excavations consisted almost entirely of midden excavations, requiring new archaeological investigations to be carried out in spaces primarily void of material remains but within the village context. Over the course of three seasons excavations, shovel test pits, and soil augers were used to obtain a variety of anthrosols and archaeological assemblages in order to generate new datasets to study Pre-Columbian activity areas. The selection of two primary case study sites were used for comparison: Indian Creek and Doigs. Findings from this research indicate that accounting for the

  16. The Development of Voiding

    DEFF Research Database (Denmark)

    Olsen, Lars Henning

    2011-01-01

    The thesis addresses some new aspeccts in the development of voiding function from midgestation into early childhood.......The thesis addresses some new aspeccts in the development of voiding function from midgestation into early childhood....

  17. Pediatric Voiding Cystourethrogram

    Science.gov (United States)

    Scan for mobile link. Children's (Pediatric) Voiding Cystourethrogram A children’s (pediatric) voiding cystourethrogram uses fluoroscopy – a form of real-time x-ray – to examine a child’s bladder ...

  18. The darkness that shaped the void : Dark energy and cosmic voids

    NARCIS (Netherlands)

    Bos, E. G. Patrick; van de Weygaert, Rien; Dolag, Klaus; Pettorino, Valeria

    2012-01-01

    We assess the sensitivity of void shapes to the nature of dark energy that was pointed out in recent studies and also investigate whether or not void shapes are useable as an observational probe in galaxy redshift surveys. Our focus is on the evolution of the mean void ellipticity and its underlying

  19. Evaluation of urologic morbidity after radiotherapy for cervical carcinoma by urodynamic examinations and patient voiding schemes: a prospective study

    DEFF Research Database (Denmark)

    Lajer, Henrik; Thranov, Ingrid R; Bagi, Per

    2002-01-01

    To assess urologic morbidity in a 5-year period by urodynamic examinations and patient voiding schemes after radiotherapy and brachytherapy for cervical carcinoma.......To assess urologic morbidity in a 5-year period by urodynamic examinations and patient voiding schemes after radiotherapy and brachytherapy for cervical carcinoma....

  20. The Cosmically Depressed: Life, Sociology and Identity of Voids

    Science.gov (United States)

    van de Weygaert, R.; Platen, E.; Tigrak, E.; Hidding, J.; van der Hulst, J. M.; Aragón-Calvo, M. A.; Stanonik, K.; van Gorkom, J. H.

    2010-10-01

    In this contribution we review and discuss several aspects of Cosmic Voids, as a background for our void galaxy project (accompanying paper by Stanonik et al.). Voids are a major component of the large scale distribution of matter and galaxies in the Universe. Following a sketch of the general characteristics of void formation and evolution, we describe the influence of the environment on their development and structure and the characteristic hierarchical buildup of the cosmic void population. In order to be able to study the resulting tenuous void substructure and the galaxies populating the interior of voids, we subsequently set out to describe our parameter free tessellation-based watershed void finding technique. It allows us to trace the outline, shape and size of voids in galaxy redshift surveys. The application of this technique enables us to find galaxies in the deepest troughs of the cosmic galaxy distribution, and has formed the basis of our void galaxy program.

  1. Study of galaxies in the Lynx-Cancer void - III. New extreme low surface brightness dwarf galaxies

    Science.gov (United States)

    Pustilnik, S. A.; Martin, J.-M.; Tepliakova, A. L.; Kniazev, A. Y.

    2011-10-01

    We present the results of a complex study of the low surface brightness dwarf (LSBD) gas-rich galaxies J0723+3621, J0737+4724 and J0852+1350, which reside in the nearby Lynx-Cancer void. Their ratios M(H I)/LB, according to H I data obtained with the Nançay Radio Telescope (NRT), are respectively ˜3.9, ˜2 and ˜2.6. For the two latter galaxies, we derived an oxygen abundance corresponding to the value of 12+log (O/H) ? 7.3, using spectra from the Russian 6-m telescope (BTA) and the Sloan Digital Sky Survey (SDSS) data base. We found two additional blue LSBDs, J0723+3622 and J0852+1351, which appear to be physical companions of J0723+3621 and J0852+1350 situated at projected distances of ˜12-13 kpc. The companion relative velocities, derived from the BTA spectra, are ΔV=+89 km s-1 and +30 km s-1 respectively. The geometry and relative orientation of orbits and spins in these pairs indicate, respectively, prograde and polar encounters for J0723+3621 and J0852+1350. The NRT H I profiles of J0723+3621 and J0723+3622 indicate a sizeable gas flow in this system. The SDSS u, g, r, i images of the five dwarfs are used to derive photometric parameters and exponential or Sersic disc model fits. For three of them, the (u-g), (g-r), (r-i) colours of the outer parts, when compared with PEGASE evolutionary tracks, provide evidence for the dominance of old stellar populations with ages of T˜ (8-10) ± 3 Gyr. For J0723+3622 and J0737+4724 the outer region colours appear rather blue, implying ages of the oldest visible stars of ? Gyr. The new LSB galaxies complement the list of known most metal-poor and 'unevolved' dwarfs in this void, including DDO 68, SDSS J0812+4836, SDSS J0926+3343 and SAO 0822+3545. This unique concentration of 'unevolved' dwarf galaxies in a small cell of the nearby Universe implies a physical relationship between slow galaxy evolution and a void-type global environment. We also compare the baryonic content of these LSBDs with predictions from the most

  2. Voids in mixed-cation silicate glasses: Studies by positron annihilation lifetime and Fourier transform infrared spectroscopies.

    Science.gov (United States)

    Reben, M; Golis, E; Filipecki, J; Sitarz, M; Kotynia, K; Jeleń, P; Grelowska, I

    2014-08-14

    PALS in comparison with FTIR studies have been applied to investigate the structure of different oxide glasses. Three components of the positron lifetime τ (τ1 para- and τ3 ortho-positronium and τ2 intermediate lifetime component) and their intensities were obtained. The results of the calculation of mean values of positron lifetimes for the investigated glasses showed the existence of a long-living component on the positron annihilation lifetime spectra. From the Tao-Eldrup formula we can estimate the size of free volume. On the basis of the measurements we can conclude that the size and fraction of free volume reaches the biggest value for the fused silica glass. The degree of network polymerisation increases void size. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. US Pilot Study of Lumbar to Sacral Nerve Rerouting to Restore Voiding and Bowel Function in Spina Bifida: 3-Year Experience

    Directory of Open Access Journals (Sweden)

    Kenneth M. Peters

    2014-01-01

    Full Text Available Objective. To report our experience with creating a skin-central nervous system-bladder reflex arc with intradural lumbar to sacral motor root microanastomosis to restore bladder/bowel function in spina bifida patients. Methods. Urinary/bowel changes from baseline to three years were evaluated with questionnaires, voiding diaries, urodynamics (UDS, and renal function studies. Treatment response was defined as CIC ≤ once/day with stable renal function, voiding efficiency > 50%, and no worsening of motor function. Results. Of 13 subjects (9 female, median age 8 years, 3 voided small amounts at baseline, one voided 200 cc (voiding efficiency 32%, 4/13 reported normal bowels, and 2/13 were continent of stool. Postoperatively, all had transient lower extremity weakness; one developed permanent foot drop. Over three years, renal function remained stable and mean maximum cystometric capacity (MCC increased (P=0.0135. In the 10 that returned at 3 years, 7 were treatment responders and 9 had discontinued antimuscarinics, but most still leaked urine. Only 2/8 with baseline neurogenic detrusor overactivity (NDO still had NDO, all 3 with compliance <10 mL/cm H2O had normalized, 7/10 considered their bowels normal, 5/10 were continent of stool, and 8/10 would undergo the procedure again. Conclusion. Lumbar to sacral nerve rerouting can improve elimination in spina bifida patients. This trial is registered with ClinicalTrials.gov NCT00378664.

  4. Voiding dysfunction - A review

    Directory of Open Access Journals (Sweden)

    Sripathi V

    2005-01-01

    Full Text Available In a child who is toilet trained the sudden onset of daytime wetting with frequency or urgency is alarming to the parents. Initially this subject was subdivided into a number of descriptive clinical conditions which led to a lot of confusion in recognition and management. Subsequently, the term elimination dysfunction was coined by Stephen Koff to emphasise the association between recurrent urinary infection, wetting, constipation and bladder overactivity. From a urodynamic point of view, in voiding dysfunction, there is either detrusor overactivity during bladder filling or dyssynergic action between the detrusor and the external sphincter during voiding. Identifying a given condition as a ′filling phase dysfunction′ or ′voiding phase dysfunction′ helps to provide appropriate therapy. Objective clinical criteria should be used to define voiding dysfunction. These include bladder wall thickening, large capacity bladder and infrequent voiding, bladder trabeculation and spinning top deformity of the urethra and a clinically demonstrated Vincent′s curtsy. The recognition and treatment of constipation is central to the adequate treatment of voiding dysfunction. Transcutaneous electric nerve stimuation for the treatment of detrusor overactivity, biofeedback with uroflow EMG to correct dyssynergic voiding, and behavioral therapy all serve to correct voiding dysfunction in its early stages. In established neurogenic bladder disease the use of Botulinum Toxin A injections into the detrusor or the external sphincter may help in restoring continence especially in those refractory to drug therapy. However in those children in whom the upper tracts are threatened, augmentation of the bladder may still be needed.

  5. Increased prostate cancer specific mortality following radical prostatectomy in men presenting with voiding symptoms—A whole of population study

    Directory of Open Access Journals (Sweden)

    Anthony D. Ta

    2015-09-01

    Conclusions: Primary Gleason pattern in Gleason 7 PC is an important prognosticator of survival. Our findings suggest that concomitant voiding symptoms should be considered in the work-up and treatment of PC.

  6. Reasons for computerised provider order entry (CPOE)-based inpatient medication ordering errors: an observational study of voided orders.

    Science.gov (United States)

    Abraham, Joanna; Kannampallil, Thomas G; Jarman, Alan; Sharma, Shivy; Rash, Christine; Schiff, Gordon; Galanter, William

    2017-07-11

    Medication voiding is a computerised provider order entry (CPOE)-based discontinuation mechanism that allows clinicians to identify erroneous medication orders. We investigated the accuracy of voiding as an indicator of clinician identification and interception of a medication ordering error, and investigated reasons and root contributors for medication ordering errors. Using voided orders identified with a void alert, we conducted interviews with ordering and voiding clinicians, followed by patient chart reviews. A structured coding framework was used to qualitatively analyse the reasons for medication ordering errors. We also compared clinician-CPOE-selected (at time of voiding), clinician-reported (interview) and chart review-based reasons for voiding. We conducted follow-up interviews on 101 voided orders. The positive predictive value (PPV) of voided orders that were medication ordering errors was 93.1% (95% CI 88.1% to 98.1%, n=94). Using chart review-based reasons as the gold standard, we found that clinician-CPOE-selected reasons were less reflective (PPV=70.2%, 95% CI 61.0% to 79.4%) than clinician-reported (interview) (PPV=86.1%, 95%CI 78.2% to 94.1%) reasons for medication ordering errors. Duplicate (n=44) and improperly composed (n=41) ordering errors were common, often caused by predefined order sets and data entry issues. A striking finding was the use of intentional violations as a mechanism to notify and seek ordering assistance from pharmacy service. Nearly half of the medication ordering errors were voided by pharmacists. We demonstrated that voided orders effectively captured medication ordering errors. The mismatch between clinician-CPOE-selected and the chart review-based reasons for error emphasises the need for developing standardised operational descriptions for medication ordering errors. Such standardisation can help in accurately identifying, tracking, managing and sharing erroneous orders and their root contributors between healthcare

  7. Nonlocal plasticity effects on interaction of different size voids

    DEFF Research Database (Denmark)

    Tvergaard, Viggo; Niordson, Christian Frithiof

    2004-01-01

    A nonlocal elastic-plastic material model is used to show that the rate of void growth is significantly reduced when the voids are small enough to be comparable with a characteristic material length. For a very small void in the material between much larger voids the competition between an increa......A nonlocal elastic-plastic material model is used to show that the rate of void growth is significantly reduced when the voids are small enough to be comparable with a characteristic material length. For a very small void in the material between much larger voids the competition between...... an increased growth rate due to the stress concentrations around the larger voids and a reduced growth rate due to the nonlocal effects is studied. The analyses are based on an axisymmetric unit cell model with special boundary conditions, which allow for a relatively simple investigation of a full three...

  8. The void galaxy survey: Star formation properties

    NARCIS (Netherlands)

    Beygu, B.; Kreckel, K.; van der Hulst, J. M.; Jarrett, T. H.; Peletier, R.; van de Weygaert, R.; van Gorkom, J. H.; Aragon-Calvo, M. A.

    2016-01-01

    We study the star formation properties of 59 void galaxies as part of the Void Galaxy Survey (VGS). Current star formation rates are derived from H α and recent star formation rates from near-UV imaging. In addition, infrared 3.4, 4.6, 12 and 22 μm Wide-field Infrared Survey Explorer emission is

  9. Assembly of filamentary void galaxy configurations

    NARCIS (Netherlands)

    Rieder, Steven; van de Weijgaert, Rien; Cautun, Marius; Beygu, Burcu; Zwart, Simon Portegies

    2013-01-01

    We study the formation and evolution of filamentary configurations of dark matter haloes in voids. Our investigation uses the high-resolution Lambda cold dark matter simulation CosmoGrid to look for void systems resembling the VGS_31 elongated system of three interacting galaxies that was recently

  10. Air void clustering.

    Science.gov (United States)

    2015-06-01

    Air void clustering around coarse aggregate in concrete has been identified as a potential source of : low strengths in concrete mixes by several Departments of Transportation around the country. Research was : carried out to (1) develop a quantitati...

  11. Experimental study of void formation during aluminum solidification in reduced gravity. Ph.D. Thesis - Toledo Univ.

    Science.gov (United States)

    Chiaramonte, Francis Paul, III

    1993-01-01

    Void formation due to volumetric shrinkage and liquid/vapor reorientation during aluminum solidification was observed in real time by using a radiographic viewing system in normal and reduced gravity. An end-chill directional solidification furnace with water quench was designed and constructed to solidify aluminum samples during the approximately 16 sec of reduced gravity (+/-0.02g) achieved by flying an aircraft through a parabolic trajectory. In the first series of tests the aluminum was contained in a vacuum sealed, pyrolytic boron nitride crucible. An ullage space was present during each test. Void formation was recorded for two cases: a nonwetting system, and a wetting system where wetting occurred between the aluminum and the crucible lid. The void formation in the nonwetting case was similar in normal and reduced gravity, with a single vapor cavity forming at the top of the crucible. In the wetting case during reduced gravity surface tension caused two voids to form in the top corners of the crucible, but during normal gravity only one large void formed across the top. In the second series of tests the aluminum was contained in a pyrolytic boron nitride crucible that was placed in a stainless steel container and sealed in an environment of argon plus 4 percent hydrogen. An ullage space was present during each test. Void formation was recorded for two cases: a nonwetting system, and a wetting system where wetting occurred between the aluminum and one side wall and the lid. The void for nation in the nonwetting case was similar in normal and reduced gravity, with a single vapor cavity forming at the top of the crucible, although the meniscus became more convex in reduced gravity. In the wetting case the aluminum did not climb up the corners in 1g, and one large symmetric void resulted at the top when the aluminum had solidified. In the wetting case during reduced gravity the molten aluminum was drawn up the wetted wall and partially across the lid by a

  12. Void and cavity determination in micro-PIXE analysis of composed material using binocular detectors: A computational study

    Science.gov (United States)

    Gholami Hatam, Ebrahim

    2017-08-01

    This study presents a new method to determine the location, size and depth of the pores in the material that is based on the asymmetry in the X-ray yield induced by proton micro-beam acquired in samples by a pair of X-ray detectors. Most of the samples have cavities within their structures that may affect the quantitative elemental concentration. Although, there are several methods to measure the porosity that are based on a physical fact. Here, we demonstrate a study that is based on the lack of X-ray absorption induced by proton along the void region. In fact, we have different X-ray absorption along the sample which results in asymmetry X-ray yield in two spectrometers positioned at backward of the probing beam. The presented approach introduces an asymmetry factor of the X-ray intensity in each of the detector to obtain an image asymmetry map. Our calculation was employed on silicon-based devices to estimate the size of the proposed cavity and the localized depth of the hole in composed material in micro-PIXE analysis. It was deduced that the presented approach is sensitive to the depth and the size of the hole in the composed material.

  13. A Study Assessing the Quality of Life Related to Voiding Symptoms and Sexual Functions in Menopausal Women

    OpenAIRE

    Chun, Ji Youn; Min, Kweon Sik; Kang, Dong Il

    2011-01-01

    Purpose To investigate the impact of menopause on the quality of life (QoL) of middle-aged and older women, including their general well-being, voiding-related symptoms, and sexual distress. Materials and Methods To assess QoL, we administered a questionnaire that included questions about voiding-related symptoms and female sexual distress and part of the Women's Health Questionnaire. The self-administered questionnaires were completed by 1,679 women in the Korea. Data for 1,262 women were av...

  14. Restoring the voids of voices by signs and gestures, in dentistry: A cross-sectional study

    Directory of Open Access Journals (Sweden)

    Suyog Jain

    2017-01-01

    Full Text Available Aims: To help dentists to communicate with the hearing impaired patients, reach an accurate diagnosis and explain the treatment plan by learning some signs and gestures used in the nonverbal communication (NVC and by devising some new signs and gestures related to dentistry which shall be easy to learn and understand both by the hearing impaired patients and the dentists. Settings and Design: The study was carried out on 100 hearing impaired students in the age group of 10–14 years in two special schools for hearing impaired children located in two different states of India, where different spoken languages and different sign languages are used. One dentist (expert dentist was trained in the NVC and the other dentist (non expert dentist had no knowledge of this type of communication, communicated the same sets of statements related to dentistry, to the hearing impaired children. One1 translator was assigned to judge their interactions. Students were asked to tell the interpreter at the end of each signed interaction what they understood from the statement conveyed to them by both the dentists. Statistical Analysis Used: All data collected were subjected to statistical analysis using Chi-square test and odds ratio test. Results: In the special school of 1st state, the nonexpert dentist conveyed only 36.3% of the information correctly to the students, whereas the expert dentist conveyed 83% of the information correctly. In the special school of 2nd state, the nonexpert dentist conveyed only 37.5% of the information correctly to the students, whereas the expert dentist conveyed 80.3% of the information correctly. Conclusions: Dentists should be made aware of the NVC and signs and gestures related to dentistry should be taught to the hearing impaired students as well as the dental students.

  15. Study on Reactive Automatic Compensation System Design

    Science.gov (United States)

    Zhe, Sun; Qingyang, Liang; Peiqing, Luo; Chenfei, Zhang

    At present, low-voltage side of transformer is public in urban distribution network, as inductive load of household appliances is increasing, the power factor decreased, this lead to a large loss of public transformer low voltage side, the supply voltage indicators can not meet user's requirements. Therefore, the design of reactive power compensation system has become another popular research. This paper introduces the principle of reactive power compensation, analyzes key technologies of reactive power compensation, design an overall program of reactive power automatic compensation system to conquer various deficiencies of reactive power automatic compensation equipment.

  16. A study assessing the quality of life related to voiding symptoms and sexual functions in menopausal women.

    Science.gov (United States)

    Chun, Ji Youn; Min, Kweon Sik; Kang, Dong Il

    2011-12-01

    To investigate the impact of menopause on the quality of life (QoL) of middle-aged and older women, including their general well-being, voiding-related symptoms, and sexual distress. To assess QoL, we administered a questionnaire that included questions about voiding-related symptoms and female sexual distress and part of the Women's Health Questionnaire. The self-administered questionnaires were completed by 1,679 women in the Korea. Data for 1,262 women were available for analysis, including premenopausal (n=307), perimenopausal (n=240), and postmenopausal (n=715) groups. Voiding-related discomfort increased significantly in perimenopausal and postmenopausal women compared with premenopausal women (psexual distress. In the menopausal group, employed women had better general well-being than did unemployed women. Menopause negatively affected the QoL of middle-aged and older women because of decreased general well-being and increased voiding-related symptoms. General health, even in menopausal women, was important to maintain a better QoL. To preserve the QoL of women undergoing menopause, control of menopause and underlying disease should be considered.

  17. Effect of void cluster on ductile failure evolution

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2016-01-01

    The behavior of a non-uniform void distribution in a ductile material is investigated by using a cell model analysis to study a material with a periodic pattern of void clusters. The special clusters considered consist of a number of uniformly spaced voids located along a plane perpendicular...

  18. Improvement of voiding characteristics in morbidly obese women after bariatric surgery: A single-center study with a 1-year follow-up.

    Science.gov (United States)

    Kim, Jae Heon; Sun, Hwa Yeon; Lee, Hyun Young; Soh, Min Ju; Park, Suyeon; Kim, Yong Jin; Song, Yun Seob

    2017-05-01

    It is well known that morbid obesity in women is related to lower urinary tract symptoms, including urinary incontinence. Although several studies have reported on the improvement in urinary incontinence after bariatric surgery, few reports have focused on the detailed changes in other voiding characteristics. To demonstrate the real benefit of bariatric surgery on lower urinary tract symptoms. Bariatric Center of Excellence and Health Promotion at Soonchunhyang University Hospital. From August to December 2012, a total of 57 women out of 183 women who underwent bariatric surgery agreed to be assessed for voiding dysfunction during their preoperative and 1-year postoperative evaluation using the international prostate symptom score, quality of life score, an overactive bladder symptom score, a patient perception of bladder score, and a Sandvick questionnaire for urinary incontinence. For statistical analysis, the Wilcoxon sign rank and Fisher׳s exact tests were used to assess a significant change in voiding status. Among a total of 183 women in the bariatric center, 57 women completed the full version of the urologic questionnaire. The baseline mean age of those patients was 38.5±9.5 and their baseline mean body mass index (BMI) was 37.5±5.9 (68.4% were over BMI 35). One year after bariatric surgery (Roux-en-Y gastric bypass), BMI showed a significant change, 9.5±3.5 (63.1% were below BMI 28). For specific characteristic changes in voiding status, the international prostate symptom score, quality of life score, overactive bladder symptom score, and patient perception of bladder score revealed significant improvement over baseline: 3.2±4.0, .6±.9, 1.6±2.3, and .5±1.0, respectively. For stress-related urinary incontinence as assessed using the Sandvick questionnaire, preoperative evaluation demonstrated the prevalence to be 40.74%, and 18.51% postoperatively. At a 1-year postoperative follow-up after laparoscopic gastric bypass-type bariatric surgery, there

  19. Void growth and coalescence in metals deformed at elevated temperature

    DEFF Research Database (Denmark)

    Klöcker, H.; Tvergaard, Viggo

    2000-01-01

    For metals deformed at elevated temperatures the growth of voids to coalescence is studied numerically. The voids are assumed to be present from the beginning of deformation, and the rate of deformation considered is so high that void growth is dominated by power law creep of the material, without...... voids. The focus of the study is on various relatively high stress triaxialties. In order to represent the results in terms of a porous ductile material model a set of constitutive relations are used, which have been proposed for void growth in a material undergoing power law creep....

  20. Attention deficit-hyperactivity disorder symptoms and daytime voiding symptoms in children with primary enuresis: an observational study to evaluate the effectiveness of desmopressin treatment.

    Science.gov (United States)

    Yang, Teng-Kai; Guo, Ya-Jun; Chang, Hong-Chiang; Yang, Hung-Ju; Huang, Kuo-How

    2015-01-01

    To evaluate the effectiveness of presence of desmopressin in treating primary enuresis (PE) for children with attention deficit-hyperactivity disorder (ADHD) symptoms. Children aged from 5 to 12 years with the chief complaint of PE treated with desmopressin were enrolled in pediatric urology clinics. The parent-reported SNAP-IV questionnaire was used to evaluate ADHD symptoms (cut-off value: 90th percentile). Voiding symptoms were assessed by the Dysfunctional Voiding Scoring System (DVSS) questionnaire. The responses to desmopressin were analyzed in children with and without ADHD symptoms. The study sample comprised 68 children; 27 (39.7%) presented with ADHD symptoms and 41 (60.3%) with non-ADHD symptoms. The children collected from a tertiary referral center may explain the high prevalence of ADHD symptoms in the present study. The total DVSS score in the ADHD symptoms group was significantly higher than in the non-ADHD symptoms group (7.72 versus 5.65, P=0.05). In the ADHD symptoms group, there were significantly higher score in the "pee 1-2 times/day" and "can't wait" subscales of DVSS and lower sleep quality based on the Pediatric Sleep Quality questionnaire, as well as significantly lower peak flow rate and voided volume. The responses to desmopressin for enuresis were comparable between children with ADHD and non-ADHD symptoms. Approximately 39.7% of PE children presented with ADHD symptoms at urologic clinics. PE children with ADHD symptoms had higher risk of daytime LUTS and comparable response to desmopressin treatment for PE. To evaluate ADHD symptoms and daytime voiding symptoms is important in children with PE.

  1. Attention Deficit-Hyperactivity Disorder Symptoms and Daytime Voiding Symptoms in Children with Primary Enuresis: An Observational Study to Evaluate the Effectiveness of Desmopressin Treatment

    Directory of Open Access Journals (Sweden)

    Teng-Kai Yang

    2015-01-01

    Full Text Available Purpose. To evaluate the effectiveness of presence of desmopressin in treating primary enuresis (PE for children with attention deficit-hyperactivity disorder (ADHD symptoms. Materials and Methods. Children aged from 5 to 12 years with the chief complaint of PE treated with desmopressin were enrolled in pediatric urology clinics. The parent-reported SNAP-IV questionnaire was used to evaluate ADHD symptoms (cut-off value: 90th percentile. Voiding symptoms were assessed by the Dysfunctional Voiding Scoring System (DVSS questionnaire. The responses to desmopressin were analyzed in children with and without ADHD symptoms. Results. The study sample comprised 68 children; 27 (39.7% presented with ADHD symptoms and 41 (60.3% with non-ADHD symptoms. The children collected from a tertiary referral center may explain the high prevalence of ADHD symptoms in the present study. The total DVSS score in the ADHD symptoms group was significantly higher than in the non-ADHD symptoms group (7.72 versus 5.65, P=0.05. In the ADHD symptoms group, there were significantly higher score in the “pee 1-2 times/day” and “can’t wait” subscales of DVSS and lower sleep quality based on the Pediatric Sleep Quality questionnaire, as well as significantly lower peak flow rate and voided volume. The responses to desmopressin for enuresis were comparable between children with ADHD and non-ADHD symptoms. Conclusions. Approximately 39.7% of PE children presented with ADHD symptoms at urologic clinics. PE children with ADHD symptoms had higher risk of daytime LUTS and comparable response to desmopressin treatment for PE. To evaluate ADHD symptoms and daytime voiding symptoms is important in children with PE.

  2. Recurrent urinary tract infection and functional voiding disorders.

    Science.gov (United States)

    Ramamurthy, H Ravi; Kanitkar, Madhuri

    2008-08-01

    This study was carried out to determine the association of recurrent urinary tract infections with functional voiding disorders. Sixty eight children with suspected functional voiding disorders were prospectively evaluated clinically and by non-invasive urodynamics. Invasive urodynamics were carried out when indicated. Group I comprised 34 children with symptoms suggestive of functional voiding disorders and recurrent urinary tract infections (mean age 6.3+/-2 yr) and Group II comprised 34 children with symptoms suggestive of functional voiding disorders without recurrent urinary tract infections (mean age 6.7+/-2 yr). The underlying bladder abnormalities in Groups I and II were detrusor instability in 22 (64.7%) and 30 (88.2%), respectively (P>0.05) and dysynergic voiding in 10 (29.4%), and 1 (2.9%), respectively (P<0.05). Children with recurrent urinary tract infections are more likely to have a dysynergic voiding pattern than children presenting with other symptoms of functional voiding disorders.

  3. Void Coalescence Processes Quantified through Atomistic and Multiscale Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Rudd, R E; Seppala, E T; Dupuy, L M; Belak, J

    2005-12-31

    Simulation of ductile fracture at the atomic scale reveals many aspects of the fracture process including specific mechanisms associated with void nucleation and growth as a precursor to fracture and the plastic deformation of the material surrounding the voids and cracks. Recently we have studied void coalescence in ductile metals using large-scale atomistic and continuum simulations. Here we review that work and present some related investigations. The atomistic simulations involve three-dimensional strain-controlled multi-million atom molecular dynamics simulations of copper. The correlated growth of two voids during the coalescence process leading to fracture is investigated, both in terms of its onset and the ensuing dynamical interactions. Void interactions are quantified through the rate of reduction of the distance between the voids, through the correlated directional growth of the voids, and through correlated shape evolution of the voids. The critical inter-void ligament distance marking the onset of coalescence is shown to be approximately one void radius based on the quantification measurements used, independent of the initial separation distance between the voids and the strain-rate of the expansion of the system. No pronounced shear flow is found in the coalescence process.

  4. Critical velocities for deflagration and detonation triggered by voids in a REBO high explosive

    Energy Technology Data Exchange (ETDEWEB)

    Herring, Stuart Davis [Los Alamos National Laboratory; Germann, Timothy C [Los Alamos National Laboratory; Jensen, Niels G [Los Alamos National Laboratory

    2010-01-01

    The effects of circular voids on the shock sensitivity of a two-dimensional model high explosive crystal are considered. We simulate a piston impact using molecular dynamics simulations with a Reactive Empirical Bond Order (REBO) model potential for a sub-micron, sub-ns exothermic reaction in a diatomic molecular solid. The probability of initiating chemical reactions is found to rise more suddenly with increasing piston velocity for larger voids that collapse more deterministically. A void with radius as small as 10 nm reduces the minimum initiating velocity by a factor of 4. The transition at larger velocities to detonation is studied in a micron-long sample with a single void (and its periodic images). The reaction yield during the shock traversal increases rapidly with velocity, then becomes a prompt, reliable detonation. A void of radius 2.5 nm reduces the critical velocity by 10% from the perfect crystal. A Pop plot of the time-to-detonation at higher velocities shows a characteristic pressure dependence.

  5. Systemic atherosclerosis and voiding symptom.

    Science.gov (United States)

    Yeniel, A Ozgur; Ergenoglu, A Mete; Meseri, Reci; Ari, Anıl; Sancar, Ceren; Itil, Ismail Mete

    2017-03-01

    To evaluate the effect of atherosclerosis on the storage and voiding symptoms of the bladder in women with overactive bladder (OAB). We retrospectively reviewed the charts of women with OAB who were evaluated between 2013 and 2015 in our urogynecology unit. Charts were assessed for history, examination findings, urinary diary, quality of life (QOL) questionnaires, urodynamic studies (UDSs), and four main risk factors for atherosclerosis: hypertension, diabetes mellitus, smoking, and hyperlipidemia. In a previous study, these were defined as vascular risk factors. Cases were excluded for insufficient data, diabetes mellitus with dysregulated blood glucose, or prolapse greater than 1cm to avoid confusing bladder outlet obstruction. We included 167 eligible cases in this study. We evaluated storage and voiding symptoms such as frequency, nocturia, residual urine volume, and voiding difficulties and UDS findings such as maximum bladder capacity, first desire, strong desire, detrusor overactivity, and bladder contractility index. The vascular risk score was categorized as "no risk" if the woman did not have any of the four risk factors and "at risk" if she had any of the factors. Independent sample t-test and chi-square tests were performed for analyses. Among the participants (n=167), 71.9% had at least one vascular risk factor. Those who were at risk were facing significantly more wet-type OAB (p=0.003) and nocturia (p=0.023). Moreover, mean age (p=0.008) and mean gravidity (p=0.020) were significantly higher in the at-risk group, whereas mean total nocturia QOL questionnaire scores (p=0.029) were significantly lower. Our findings suggest that aging and atherosclerosis may be associated with severe OAB and poorer QOL. Nocturia and related parameters of poor quality can be explained by impaired bladder neck perfusion. Future trials need to assess vascular and molecular changes in women with OAB. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Baryon effects on void statistics in the EAGLE simulation

    Science.gov (United States)

    Paillas, Enrique; Lagos, Claudia D. P.; Padilla, Nelson; Tissera, Patricia; Helly, John; Schaller, Matthieu

    2017-10-01

    Cosmic voids are promising tools for cosmological tests due to their sensitivity to dark energy, modified gravity and alternative cosmological scenarios. Most previous studies in the literature of void properties use cosmological N-body simulations of dark matter (DM) particles that ignore the potential effect of baryonic physics. Using a spherical underdensity finder, we analyse voids using the mass field and subhalo tracers in the Evolution and Assembly of Galaxies and their Environment (EAGLE) simulations, which follow the evolution of galaxies in a Λ cold dark matter universe with state-of-the-art subgrid models for baryonic processes in a (100 cMpc)3 volume. We study the effect of baryons on void statistics by comparing results with DM-only simulations that use the same initial conditions as EAGLE. When identifying voids in the mass field, we find that a DM-only simulation produces 24 per cent more voids than a hydrodynamical one due to the action of galaxy feedback polluting void regions with hot gas, specially for small voids with rvoid ≤ 10 Mpc. We find that the way in which galaxy tracers are selected has a strong impact on the inferred void properties. Voids identified using galaxies selected by their stellar mass are larger and have cuspier density profiles than those identified by galaxies selected by their total mass. Overall, baryons have minimal effects on void statistics, as void properties are well captured by DM-only simulations, but it is important to account for how galaxies populate DM haloes to estimate the observational effect of different cosmological models on the statistics of voids.

  7. Abnormal voiding parameters in children with severe idiopathic constipation.

    Science.gov (United States)

    Chung, K L Y; Chao, N S Y; Liu, C S W; Tang, P M Y; Liu, K K W; Leung, M W Y

    2014-07-01

    It is suggested that idiopathic constipation may associate with abnormal voiding parameters. In this study, we investigate the voiding parameters in children with constipation. Since 2010, seventeen consecutive children (12 boys, 5 girls) aged 5-17 (median = 14) with significant constipation according to Rome III criteria and who were not responding to conventional treatment (diet, laxatives & bowel training) for over 6 months were recruited. The rectal diameter (RD) was measured by transpubic ultrasonography (USG), RD >3.5 cm was considered as dilated. Each patient had uroflow measurement and bladder USG done to measure the maximal flow rate (Vmax), voided volume (VV), and post-void residual urine (PVR). Abnormal voiding parameters were defined as Vmax 150% of age-adjusted expected bladder capacity (EBC) and/or PVR >20 ml. Rectal diameter ranged from 1.7 to 8.2 cm (median = 3 cm) and was abnormally dilated in eight children. Vmax was normal in all children (median = 23.7 ml/sec). Voided volume ranged from 30 to 289% of EBC and was abnormal in six children (35.5%). Post-void residual urine varied from 0 to 85 ml and was abnormal in six (35.5 %) children. Three children (17.6 %) had both abnormal VV and PVR. On the whole, the prevalence of abnormal voiding parameters in constipated children was 52.9 %. Mean RD in normal and abnormal parameters groups was 2.8 and 4.7 cm, respectively. Rectal dilation was associated with abnormal voiding parameters (p = 0.015). Abnormal voiding parameters including voided volume and post-void residual urine are prevalent in constipated children. Dilated rectum is associated with abnormal voiding parameters.

  8. Shock Compression of Solid with Voids by Gridless Lagrangian SPH

    Science.gov (United States)

    Tanaka, Katsumi

    2006-07-01

    The mechanism of formation of local hot spots with a single or multiple voids has been studied numerically by Smoothed Particle Hydrodynamics (SPH). Temperature increase was not enough to initiate emulsion explosives for incident shock pressure lower than 10GPa in the case of single void. It is important for formation of local hot spot to consider complex physical interaction and chemistry in multiple voids.

  9. CT measurements of SAP voids in concrete

    DEFF Research Database (Denmark)

    Laustsen, Sara; Bentz, Dale P.; Hasholt, Marianne Tange

    2010-01-01

    X-ray computed tomography (CT) scanning is used to determine the SAP void distribution in hardened concrete. Three different approaches are used to analyse a binary data set created from CT measurement. One approach classifies a cluster of connected, empty voxels (volumetric pixel of a 3D image......) as one void, whereas the other two approaches are able to classify a cluster of connected, empty voxels as a number of individual voids. Superabsorbent polymers (SAP) have been used to incorporate air into concrete. An advantage of using SAP is that it enables control of the amount and size...... to calculate the liquid absorption of the SAP within the fresh concrete. This estimated liquid absorption is in reasonable agreement with previous studies....

  10. Quantifying Effects of Voids in Woven Ceramic Matrix Composites

    Science.gov (United States)

    Goldsmith, Marlana B.; Sankar, Bhavani V.; Haftka, Raphael T.; Goldberg, Robert K.

    2013-01-01

    Randomness in woven ceramic matrix composite architecture has been found to cause large variability in stiffness and strength. The inherent voids are an aspect of the architecture that may cause a significant portion of the variability. A study is undertaken to investigate the effects of many voids of random sizes and distributions. Response surface approximations were formulated based on void parameters such as area and length fractions to provide an estimate of the effective stiffness. Obtaining quantitative relationships between the properties of the voids and their effects on stiffness of ceramic matrix composites are of ultimate interest, but the exploratory study presented here starts by first modeling the effects of voids on an isotropic material. Several cases with varying void parameters were modeled which resulted in a large amount of variability of the transverse stiffness and out-of-plane shear stiffness. An investigation into a physical explanation for the stiffness degradation led to the observation that the voids need to be treated as an entity that reduces load bearing capabilities in a space larger than what the void directly occupies through a corrected length fraction or area fraction. This provides explanation as to why void volume fraction is not the only important factor to consider when computing loss of stiffness.

  11. Efficacy and safety of solifenacin plus tamsulosin OCAS in men with voiding and storage lower urinary tract symptoms: results from a phase 2, dose-finding study (SATURN).

    Science.gov (United States)

    Van Kerrebroeck, Philip; Haab, François; Angulo, Javier C; Vik, Viktor; Katona, Ferenc; Garcia-Hernandez, Alberto; Klaver, Monique; Traudtner, Klaudia; Oelke, Matthias

    2013-09-01

    Storage symptoms are often undertreated in men with lower urinary tract symptoms (LUTS). To evaluate the combination of an antimuscarinic (solifenacin) with an α-blocker (tamsulosin) versus tamsulosin alone in the treatment of men with LUTS. A double-blind, 12-wk, phase 2 study in 937 men with LUTS (≥ 3 mo, total International Prostate Symptom Score [IPSS] ≥ 13, and maximum urinary flow rate 4.0-15.0 ml/s). Eight treatment groups: tamsulosin oral controlled absorption system (OCAS) 0.4 mg; solifenacin 3, 6, or 9 mg; solifenacin 3, 6 or 9 mg plus tamsulosin OCAS 0.4 mg; or placebo. The primary efficacy end point was change from baseline in total IPSS. Secondary end points included micturition diary and quality-of-life (QoL) parameters. Post hoc subgroup analyses were performed by severity of baseline storage symptoms, with statistical comparisons presented only for tamsulosin OCAS alone versus combination therapy, due to the small sample size of the solifenacin monotherapy and placebo subgroups. Combination therapy was associated with significant improvements in micturition frequency and voided volume versus tamsulosin OCAS alone in the total study population; improvements in total IPSS were not significant. Statistically significant improvements in urgency episodes, micturition frequency, total urgency score, voided volume, IPSS storage subscore, IPSS-QoL index, and Patient Perception of Bladder Condition were observed in a subpopulation of men with two or more urgency episodes per 24h (Patient Perception of Intensity of Urgency Scale grade 3 or 4) and eight or more micturitions per 24h at baseline (storage symptoms subgroup) with combination therapy versus tamsulosin OCAS alone (p ≤ 0.05 for the dose-response slope, all variables). Combination therapy was well tolerated, and adverse events were consistent with the safety profiles of both compounds. Solifenacin plus tamsulosin OCAS did not significantly improve IPSS in the total study population but offered

  12. The number of voiding radiographs during cystourethrography in women with stress incontinence or prolapse can be reduced to enhance safety without compromising study interpretation.

    Science.gov (United States)

    Guild, Jeffrey; Takacs, Elizabeth; Kircher, Stephen; Arbique, Gary; Zimmern, Philippe E

    2009-01-01

    Based on a prior study, over 60% of the average radiation dose per cystourethrography (CU) originated from lateral radiograph images (RI). This analysis focuses on the feasibility of decreasing the number of RI without compromising study interpretation. Following IRB approval, all RIs from the initial study in women with incontinence and/or bladder prolapse were assessed at random for reading consistency (inter-rater reliability (IRR)) and reliability (intra-rater reliability (IaRR)) by four independent reviewers. Interpretation guidelines on urethral readability were established and 15 repeated RIs tested for IaRR. Two months later, the reviewers selected the best two RIs for each CU with the RI presented in a random order. From 88 CU exams providing 304 RIs, good IRRs for readability (kappa=0.82, ICC=0.80) and interpretation (kappa=0.60, ICC=0.57) were found between reviewers. Mean IaRR for readable versus unreadable categories was 87% and among readable images was 95% for interpretation. The RIs judged best had a high IRR (kappa=0.83, ICC=0.83) and were predominantly from the early and middle phases of the void. A high level of agreement was found for urethral readability and interpretation between reviewers of varying experience using pre-established guidelines. No more than 3 RIs were required for study interpretation and those views were from the early to middle phase of voiding, thus allowing a radiation dose reduction without compromising the quality of the CU exam. Neurourol. Urodynam. 28:385-389, 2009. (c) 2008 Wiley-Liss, Inc.

  13. Halo abundances and shear in void models

    DEFF Research Database (Denmark)

    Alonso, David; García-Bellido, Juan; Haugbølle, Troels

    2012-01-01

    We study the non-linear gravitational collapse of dark matter into halos through numerical N-body simulations of Lemaitre-Tolman-Bondi void models. We extend the halo mass function formalism to these models in a consistent way. This extension not only compares well with the simulated data at all...

  14. CERAMENT treatment of fracture defects (CERTiFy): protocol for a prospective, multicenter, randomized study investigating the use of CERAMENT™ BONE VOID FILLER in tibial plateau fractures.

    Science.gov (United States)

    Nusselt, Thomas; Hofmann, Alexander; Wachtlin, Daniel; Gorbulev, Stanislav; Rommens, Pol Maria

    2014-03-08

    Bone graft substitutes are widely used for reconstruction of posttraumatic bone defects. However, their clinical significance in comparison to autologous bone grafting, the gold-standard in reconstruction of larger bone defects, still remains under debate. This prospective, randomized, controlled clinical study investigates the differences in pain, quality of life, and cost of care in the treatment of tibia plateau fractures-associated bone defects using either autologous bone grafting or bioresorbable hydroxyapatite/calcium sulphate cement (CERAMENT™|BONE VOID FILLER (CBVF)). CERTiFy (CERament™ Treatment of Fracture defects) is a prospective, multicenter, controlled, randomized trial. We plan to enroll 136 patients with fresh traumatic depression fractures of the proximal tibia (types AO 41-B2 and AO 41-B3) in 13 participating centers in Germany. Patients will be randomized to receive either autologous iliac crest bone graft or CBVF after reduction and osteosynthesis of the fracture to reconstruct the subchondral bone defect and prevent the subsidence of the articular surface. The primary outcome is the SF-12 Physical Component Summary at week 26. The co-primary endpoint is the pain level 26 weeks after surgery measured by a visual analog scale. The SF-12 Mental Component Summary after 26 weeks and costs of care will serve as key secondary endpoints. The study is designed to show non-inferiority of the CBVF treatment to the autologous iliac crest bone graft with respect to the physical component of quality of life. The pain level at 26 weeks after surgery is expected to be lower in the CERAMENT bone void filler treatment group. CERTiFy is the first randomized multicenter clinical trial designed to compare quality of life, pain, and cost of care in the use of the CBVF and the autologous iliac crest bone graft in the treatment of tibia plateau fractures. The results are expected to influence future treatment recommendations. ClinicalTrials.gov: NCT01828905.

  15. Study of galaxies in the Lynx-Cancer void. VI. H I-observations with Nançay Radio Telescope

    Science.gov (United States)

    Pustilnik, S. A.; Martin, J.-M.

    2016-12-01

    Context. Void population consists mainly of late-type and low surface brightness (LSB) dwarf galaxies, whose atomic hydrogen is the main component of their baryonic matter. Therefore observations of void galaxy Hi are mandatory to understand both their evolution and dynamics. Aims: Our aim was to obtain integrated Hi parameters for a fainter part of the nearby Lynx-Cancer void galaxy sample (total of 45 objects) with the Nançay Radio Telescope (NRT) and to conduct the comparative analysis of the whole 103 void galaxies with known Hi data with a sample of similar galaxies residing in denser environments of the Local Volume. Methods: For Hi observations we used the NRT with its sensitive antenna/receiver system FORT and standard processing. The comparison of the void and "control" samples on the parameter M(HI)/LB is conducted with the non-parametric method "The 2 × 2 Contingency Table test". Results: We obtained new Hi data for about 40% of the Lynx-Cancer galaxy sample. Along with data from the literature, we use for further analysis data for 103 void objects. The proxy of the evolutional parameter M(HI)/LB of the void sample is compared with that of 82 galaxies of morphological types 8-10 residing in the Local Volume groups and aggregates. Conclusions: At the confidence level of P = 0.988, we conclude that for the same luminosity, these void galaxies are systematically gas-richer, in average by 39%. This result is consistent with the authors' earlier conclusion on the smaller gas metallicities and evidences for the slower low-mass galaxy evolution in voids. The reduced spectra (FITS files) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/596/A86

  16. Extended void merging tree algorithm for self-similar models

    NARCIS (Netherlands)

    Russell, Esra

    In hierarchical evolution, voids exhibit two different behaviours related with their surroundings and environments, they can merge or collapse. These two different types of void processes can be described by the two-barrier excursion set formalism based on Brownian random walks. In this study, the

  17. An Interacting Galaxy System along a Filament in a Void

    NARCIS (Netherlands)

    Beygu, B.; Kreckel, K.; van de Weijgaert, R.; van der Hulst, J. M.; van Gorkom, J. H.

    Cosmological voids provide a unique environment for the study of galaxy formation and evolution. The galaxy population in their interiors has properties significantly different from average field galaxies. As part of our Void Galaxy Survey (VGS), we have found a system of three interacting galaxies

  18. The relationship between children with voiding problems and their parents

    NARCIS (Netherlands)

    Labrie, J.; de Jong, T. P. V. M.; Nieuwhof-Leppink, A.; van der Deure, J.; Vijverberg, M. A. W.; van der Vaart, C. H.

    2010-01-01

    We determined whether parents of children with overactive bladder and dysfunctional voiding had had similar symptoms in childhood. A case-control study was done in parents with and without children with overactive bladder or dysfunctional voiding. All were recruited from an outpatient clinic.

  19. Results of double-blind placebo-controlled crossover study of sildenafil citrate (Viagra) in women suffering from obstructed voiding or retention associated with the primary disorder of sphincter relaxation (Fowler's Syndrome).

    Science.gov (United States)

    Datta, Soumendra N; Kavia, Rajesh B C; Gonzales, Gwen; Fowler, Clare J

    2007-02-01

    Women with the primary disorder of sphincter relaxation find voiding difficult. Studies have identified neuronal nitric oxide synthase in the female urethral sphincter, and nitric oxide donors have been shown to decrease sphincter pressures. The aim of our study was to determine if sildenafil could improve sphincter relaxation and thereby increase flow rates and improve bladder emptying. Twenty women with complete (5), partial retention or obstructed voiding (15) with a maximum flow rate (Qmax) of less than 15 ml/min with an elevated maximal urethral closure pressure (92--age cm H(2)O) and sphincter volume (>1.6 cm(3)) were included in the study. The study was a double-blind, randomised, placebo-control, crossover design, with patients taking sildenafil or placebo, and with measurement of flow rate and residual volume at baseline and after each treatment phase. Voiding diary, quality of life, and International Prostate Symptom Score (IPSS) data were also collected. No statistical significant difference was seen in any voiding parameters and diaries when sildenafil citrate was compared with placebo. There was a significant mean decrease in IPSS of 3.64 between baseline and the sildenafil phase (p=0.0083), but not when compared with placebo. In the subgroup of women with partial retention and obstructed voiding (15/20), there was a statistically significant increase in Qmax of 4.7 ml/sec (p=0.025) between sildenafil and baseline; however this difference was not seen when compared with placebo. This is the first study looking at sildenafil in voiding dysfunction in women. Clinical improvements with sildenafil were not significant when compared with placebo. Sildenafil was not effective as a therapeutic pharmacologic agent in this group of patients.

  20. Air void clustering : [technical summary].

    Science.gov (United States)

    2015-06-01

    Air void clustering around coarse aggregate in concrete has been : identified as a potential source of low strengths in concrete mixes by : several Departments of Transportation around the country. Research : was carried out to (1) develop a quantita...

  1. Preparation and reactivity studies of maleimidophenyl glycidylether ...

    African Journals Online (AJOL)

    alkali/solvent) and water absorption resistance. Morphological studies by the SEM technique further confirmed the phase homogeneity network of the cured systems. KEY WORDS: Amine, Epoxy resin, Maleimide, Curing, Epichlorohydrin. Bull.

  2. Warmth elevating the depths: shallower voids with warm dark matter

    Science.gov (United States)

    Yang, Lin F.; Neyrinck, Mark C.; Aragón-Calvo, Miguel A.; Falck, Bridget; Silk, Joseph

    2015-08-01

    Warm dark matter (WDM) has been proposed as an alternative to cold dark matter (CDM), to resolve issues such as the apparent lack of satellites around the Milky Way. Even if WDM is not the answer to observational issues, it is essential to constrain the nature of the dark matter. The effect of WDM on haloes has been extensively studied, but the small-scale initial smoothing in WDM also affects the present-day cosmic web and voids. It suppresses the cosmic `sub-web' inside voids, and the formation of both void haloes and subvoids. In N-body simulations run with different assumed WDM masses, we identify voids with the ZOBOV algorithm, and cosmic-web components with the ORIGAMI algorithm. As dark-matter warmth increases (i.e. particle mass decreases), void density minima grow shallower, while void edges change little. Also, the number of subvoids decreases. The density field in voids is particularly insensitive to baryonic physics, so if void density profiles and minima could be measured observationally, they would offer a valuable probe of the nature of dark matter. Furthermore, filaments and walls become cleaner, as the substructures in between have been smoothed out; this leads to a clear, mid-range peak in the density PDF.

  3. The cosmic web in CosmoGrid void regions

    Science.gov (United States)

    Rieder, Steven; van de Weygaert, Rien; Cautun, Marius; Beygu, Burcu; Portegies Zwart, Simon

    2016-10-01

    We study the formation and evolution of the cosmic web, using the high-resolution CosmoGrid ΛCDM simulation. In particular, we investigate the evolution of the large-scale structure around void halo groups, and compare this to observations of the VGS-31 galaxy group, which consists of three interacting galaxies inside a large void. The structure around such haloes shows a great deal of tenuous structure, with most of such systems being embedded in intra-void filaments and walls. We use the Nexus+} algorithm to detect walls and filaments in CosmoGrid, and find them to be present and detectable at every scale. The void regions embed tenuous walls, which in turn embed tenuous filaments. We hypothesize that the void galaxy group of VGS-31 formed in such an environment.

  4. Structural control of void formation in dual phase steels

    DEFF Research Database (Denmark)

    Azuma, Masafumi

    The objective of this study is to explore the void formation mechanisms and to clarify the influence of the hardness and structural parameters (volume fraction, size and morphology) of martensite particles on the void formation and mechanical properties in dual phase steels composed of ferrite...... measurements, tensile tests and hole-expansion tests. The initial microstructure and the deformed microstructure were characterized by means of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In situ tensile tests in a SEM were applied for direct observation of the void formation...... of the martensite accelerates the void formation in the martensite by enlarging the size of voids both in the martensite and ferrite. It is suggested that controlling the hardness and structural parameters associated with the martensite particles such as morphology, size and volume fraction are the essential...

  5. Voiding dysfunctions in children with mental retardation.

    Science.gov (United States)

    Yang, Pei-Yu; Meng, Nai-Hsin; Chou, Eric Chieh-lung

    2010-09-01

    This study aims to evaluate the voiding disorder and lower urinary tract symptoms in mentally retarded children. Fifty-one mentally retarded children (age 7.7 years) was assessed. A volunteer sample comprised of 36 typically developing children (age 6.4 years) served as the comparative group. All participants underwent uroflometric investigation, and residual urine was detected by sonography. Urological history including history of urinary tract infection, incontinence, frequency, and dysurea was collected. In addition, the mentally retarded group was classified according to IQ: severe mentally retarded group (IQ below 40) (n = 11), moderate mentally retarded group (IQ: 41 to 55) (n = 19), mild mentally retarded group (IQ: 56 to 70) (n = 21). Group comparisons were analyzed using Chi-square and Student's t-test. Of the 51 mentally retarded children, 18(35.2%) were found to have voiding dysfunction, which is significantly higher than the control group (8.3%). The incidence of urine incontinence and frequency is also significantly higher in the mentally retarded group. The comparison of the three mentally retarded subgroups showed that the severe mentally retarded group had the highest incidence of voiding dysfunction and urinary incontinence. Overall, the mentally retarded group had higher percentage of small bladder capacity. We concluded that mentally retarded children have a higher incidence of voiding dysfunction and incontinence than the control group. Early detection of voiding dysfunction in an objective, non-invasive manner is important in mentally retarded children, particularly those with severe cognitive impairment. © 2009 Wiley-Liss, Inc.

  6. An experimental study of reactive turbulent mixing

    Science.gov (United States)

    Cooper, L. P.; Marek, C. J.; Strehlow, R. A.

    1977-01-01

    An experimental study of the turbulent mixing of two coaxial gas streams, which react very rapidly (pseudo-hypergolic chemical kinetics), was performed to investigate the mixing characteristics of turbulent flow fields. The center stream consisted of a CO-N2 mixture and the outer annular stream consisted of air vitiated by H2 combustion. The streams were at equal velocity (50 m/sec) and temperature (1280 K). Turbulence measurements were obtained using hot film anemometry. A sampling probe was used to obtain time averaged gas compositions. Six different turbulence generators were placed in the annular passage to alter the flow field mixing characteristics. The turbulence generators affected the bulk mixing of the streams and the extent of CO conversion to different degrees. The effects can be related to the average eddy size and the bulk mixing. Higher extents of conversion of CO to CO2 were found by increasing the bulk mixing and decreasing the average eddy size.

  7. Alignment of voids in the cosmic web

    NARCIS (Netherlands)

    Platen, Erwin; van de Weygaert, Rien; Jones, Bernard J. T.

    2008-01-01

    We investigate the shapes and mutual alignment of voids in the large-scale matter distribution of a Lambda cold dark matter (Lambda CDM) cosmology simulation. The voids are identified using the novel watershed void finder (WVF) technique. The identified voids are quite non-spherical and slightly

  8. Reference values for methacholine reactivity (SAPALDIA study

    Directory of Open Access Journals (Sweden)

    Perruchoud André

    2005-11-01

    Full Text Available Abstract Background The distribution of airway responsiveness in a general population of non-smokers without respiratory symptoms has not been established, limiting its use in clinical and epidemiological practice. We derived reference equations depending on individual characteristics (i.e., sex, age, baseline lung function for relevant percentiles of the methacholine two-point dose-response slope. Methods In a reference sample of 1567 adults of the SAPALDIA cross-sectional survey (1991, defined by excluding subjects with respiratory conditions, responsiveness during methacholine challenge was quantified by calculating the two-point dose-response slope (O'Connor. Weighted L1-regression was used to estimate reference equations for the 95th , 90th , 75th and 50th percentiles of the two-point slope. Results Reference equations for the 95th , 90th , 75th and 50th percentiles of the two-point slope were estimated using a model of the form a + b* Age + c* FEV1 + d* (FEV12 , where FEV1 corresponds to the pre-test (or baseline level of FEV1. For the central half of the FEV1 distribution, we used a quadratic model to describe the dependence of methacholine slope on baseline FEV1. For the first and last quartiles of FEV1, a linear relation with FEV1 was assumed (i.e., d was set to 0. Sex was not a predictor term in this model. A negative linear association with slope was found for age. We provide an Excel file allowing calculation of the percentile of methacholine slope of a subject after introducing age – pre-test FEV1 – and results of methacholine challenge of the subject. Conclusion The present study provides equations for four relevant percentiles of methacholine two-point slope depending on age and baseline FEV1 as basic predictors in an adult reference population of non-obstructive and non-atopic persons. These equations may help clinicians and epidemiologists to better characterize individual or population airway responsiveness.

  9. Study of methyl bromide reactivity with human and mouse hemoglobin

    African Journals Online (AJOL)

    A study has been carried out on in-vitro reactivity of human and mouse hemoglobin spectrophotometrically at physiological pH, using different protein to reagent ratios. Hemoglobin side chains were modified with different concentrations of methyl bromide on agro-soil fumigant. To ascertain if the site of alkylation was the ...

  10. Reactivity Studies of 2,6-Ditriazolylpurine Nucleosides with Nucleophiles

    OpenAIRE

    Kovaļovs, A; Novosjolova, I; Bizdēna, Ē; Turks, M

    2012-01-01

    Reaction of 2,6-ditriazolylpurine nucleosides with nucleophiles is mild and efficient route to C6 derivatization of purine base. To explore scope and limitations of the method, we studied reactivity of various N- and S-nucleophiles as well as kinetics for selected reactions.

  11. Electrical discharge machining studies on reactive sintered FeAl

    Indian Academy of Sciences (India)

    Electrical discharge machining (EDM) studies on reactive sintered FeAl were carried out with different process parameters. The metal removal rate and tool removal rate were found to increase with the applied pulse on-time. The surface roughness of machined surface also changed with the applied pulse on-time.

  12. Assembly of filamentary void galaxy configurations

    Science.gov (United States)

    Rieder, Steven; van de Weygaert, Rien; Cautun, Marius; Beygu, Burcu; Portegies Zwart, Simon

    2013-10-01

    We study the formation and evolution of filamentary configurations of dark matter haloes in voids. Our investigation uses the high-resolution Λ cold dark matter simulation CosmoGrid to look for void systems resembling the VGS_31 elongated system of three interacting galaxies that was recently discovered by the Void Galaxy Survey inside a large void in the Sloan Digital Sky Survey galaxy redshift survey. H I data revealed these galaxies to be embedded in a common elongated envelope, possibly embedded in intravoid filament. In the CosmoGrid simulation we look for systems similar to VGS_31 in mass, size and environment. We find a total of eight such systems. For these systems, we study the distribution of neighbour haloes, the assembly and evolution of the main haloes and the dynamical evolution of the haloes, as well as the evolution of the large-scale structure in which the systems are embedded. The spatial distribution of the haloes follows that of the dark matter environment. We find that VGS_31-like systems have a large variation in formation time, having formed between 10 Gyr ago and the present epoch. However, the environments in which the systems are embedded evolved to resemble each other substantially. Each of the VGS_31-like systems is embedded in an intravoid wall, that no later than z = 0.5 became the only prominent feature in its environment. While part of the void walls retain a rather featureless character, we find that around half of them are marked by a pronounced and rapidly evolving substructure. Five haloes find themselves in a tenuous filament of a few h-1 Mpc long inside the intravoid wall. Finally, we compare the results to observed data from VGS_31. Our study implies that the VGS_31 galaxies formed in the same (proto)filament, and did not meet just recently. The diversity amongst the simulated halo systems indicates that VGS_31 may not be typical for groups of galaxies in voids.

  13. influence of orientation and size of voids on concrete cube strength

    African Journals Online (AJOL)

    Dr Obe

    25°, 35°, 45° to the horizontal axis of as-cast face of hollow concrete cubes were investigated. Analysis of the four grades of concrete studied showed that both void orientation and size of voids have influence on the uniaxial compressive strength of hollow concrete cubes. It showed that 45° void orientation has the highest ...

  14. Voids characteristics of asphaltic concrete containing coconut shell

    Science.gov (United States)

    Ezree Abdullah, Mohd; Hannani Madzaili, Amirah; Putra Jaya, Ramadhansyah; Yaacob, Haryati; Hassan, Norhidayah Abdul; Nazri, Fadzli Mohamed

    2017-07-01

    Asphalt durability is often linked to the thickness of the asphalt coating on the aggregate particles. In order to have adequate film thickness in asphaltic concrete, there must be sufficient space between the aggregate particles in the compacted pavement. This void space is referred to as voids in total mix (VTM), voids with filled bitumen (VFB), and voids in mineral aggregate (VMA). Hence, this study investigates the performance of coconut shell (CS) as coarse aggregate replacement on voids characteristics of asphaltic concrete. Four CS were used as coarse aggregates replacement in asphalt mixture namely 0%, 10%, 20%, 30%, and 40% (by weight volume). The voids properties of asphalt mixture were determined based on Marshall Mix design test. Test results show that VTM and VMA values were decrease with the increasing bitumen content where VFB was increase with increasing bitumen content. Furthermore, increasing the percentage of coconut shell in asphalt mixture was found to increases the voids value up to a peak level and then decreases with further additions of CS.

  15. Perineal Surface Electromyography Does Not Typically Demonstrate Expected Relaxation During Normal Voiding

    Science.gov (United States)

    Kirby, Anna C.; Nager, Charles W.; Litman, Heather J.; FitzGerald, Mary P.; Kraus, Stephen; Norton, Peggy; Sirls, Larry; Rickey, Leslie; Wilson, Tracey; Dandreo, Kimberly J.; Shepherd, Jonathan; Zimmern, Philippe

    2015-01-01

    Aims To describe perineal surface patch electromyography (EMG) activity during urodynamics (UDS) and compare activity between filling and voiding phases and to assess for a relationship between preoperative EMG activity and postoperative voiding symptoms. Methods 655 women underwent standardized preoperative UDS that included perineal surface EMG prior to undergoing surgery for stress urinary incontinence. Pressure-flow studies were evaluated for abdominal straining and interrupted flow. Quantitative EMG values were extracted from 10 predetermined time-points and compared between fill and void. Qualitative EMG activity was assessed for the percent of time EMG was active during fill and void and for the average amplitude of EMG during fill compared to void. Postoperative voiding dysfunction was defined as surgical revision or catheterization more than 6 weeks after surgery. Fisher’s exact test with a 5% two-sided significance level was used to assess differences in EMG activity and postoperative voiding dysfunction. Results 321 UDS had interpretable EMG studies, of which 131 (41%) had EMG values at all 10 predetermined and annotated time-points. Quantitative and qualitative EMG signals during flow were usually greater than during fill. The prevalence of postoperative voiding dysfunction in subjects with higher preoperative EMG activity during void was not significantly different. Results were similar in the 42 subjects who had neither abdominal straining during void nor interrupted flow. Conclusions Perineal surface patch EMG did not measure expected pelvic floor and urethral sphincter relaxation during voiding. Preoperative EMG did not predict patients at risk for postoperative voiding dysfunction. PMID:21560157

  16. Finding Brazing Voids by Holography

    Science.gov (United States)

    Galluccio, R.

    1986-01-01

    Vibration-induced interference fringes reveal locations of defects. Holographic apparatus used to view object while vibrated ultrasonically. Interference fringes in hologram reveal brazing defects. Holographic technique locates small voids in large brazed joints. Identifies unbrazed regions 1 in. to second power (6 cm to the second power) or less in area.

  17. A confinement induced spectroscopic study of noble gas atoms using equation of motion architecture: Encapsulation within fullerene's voids

    Science.gov (United States)

    Chaudhuri, Supriya K.; Chaudhuri, Rajat K.; Mukherjee, Prasanta K.; Chattopadhyay, Sudip

    2017-07-01

    A relativistic study of spectroscopic properties of the endohedral fullerenes Ng@C60q (where Ng = He, Ne and q =0 ,±1 ,±2 are the charges) associated with the C60 molecule has been done using the equation of motion coupled cluster (EOM-CC) methodology. Specific properties estimated are the transition energies, dipole oscillator strengths, and transition probabilities for the low-lying excitations 1s2(1S0) → 1 s n p (1P1) (n = 2, 3, 4) for He@C60q and 1s22s22p6 (1S0) → 1 s22 s22 p5n s /n d (1P1) (n = 3, 4) for Ne@C60q, which have been compared with those for the isolated atom to depict the confinement effect of the host molecule on the encapsulated atom. This is accomplished by introducing an effective potential to the atomic Hamiltonian induced by the fullerene moiety and its charge. The EOM-CC results have been compared with those estimated with the random phase approximation (and configuration interaction singles) to understand the effect of electron correlation under such confinement. The systematic and interesting behavior of the properties is highlighted indicating the effect of fullerene cage potential on the redistribution of electron density of the guest atom.

  18. Synthesis, reactivity studies and biological evaluation of novel bisphosphonates

    OpenAIRE

    2014-01-01

    Ph.D. (Chemistry) This thesis was devoted to the synthesis of new bisphosphonates molecules, the study of their reactivity and the evaluation of their biological activities. The synthesis of epoxyalkylgembisphosphonates was carried out in three steps. The first step was the synthesis of arynyl and alkynylphosphonates by metallation of alkyl and aryl acetylenes followed by condensation with diethylchlorophosphate at low temperature. The second step was the synthesis of vinylgembisphosphonat...

  19. A retrospective observational study of enuresis, daytime voiding symptoms, and response to medical therapy in children with attention deficit hyperactivity disorder and autism spectrum disorder.

    Science.gov (United States)

    Gor, Ronak A; Fuhrer, Jamie; Schober, Justine M

    2012-06-01

    Children with attention deficit hyperactivity disorder (ADHD) show an increased prevalence of enuresis and other daytime voiding symptoms (DVS). There is also some evidence toward an increased prevalence of enuresis among children with autism spectrum disorder (ASD), but with no data available with respect to DVS or response to medical treatment. The aim of this study was to assess enuresis and DVS, along with treatment outcomes, in children with ASD, to aid urological management. A retrospective observational study on the incidence of enuresis and other DVS in 671 children with/without ADHD/ASD was performed. Symptomatic improvement ≥50% was required to be considered positive. Complete resolution of symptoms for 3 months after cessation of treatment was considered cure. Symptomatic improvement with desmopressin or anticholinergic treatment was seen in 76% of patients without ADHD/ASD, 85% of patients with ADHD, and 100% of patients with ASD. Cure was seen in 61% of patients without ADHD/ASD, 48% of patients with ADHD, and 50% patients with ASD. Mean time to cure was 9 months in those without ADHD/ASD (N = 319), 10 months in those with ADHD (N = 62), and 8 months in those with ASD (N = 10) (P = 0.69). Despite the small sample size of patients with ASD, our data show a favorable trend toward efficacy of desmopressin and anticholinergic therapy in these children with enuresis and DVS. Copyright © 2010 Journal of Pediatric Urology Company. Published by Elsevier Ltd. All rights reserved.

  20. Effect of initial void shape on ductile failure in a shear field

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2015-01-01

    For voids in a shear field unit cell model analyses have been used to show that ductile failure is predicted even though the stress triaxiality is low or perhaps negative, so that the void volume fraction does not grow during deformation. Here, the effect of the void shape is studied by analyzing...... with circular cross-section, i.e. the voids in shear flatten out to micro-cracks, which rotate and elongate until interaction with neighboring micro-cracks gives coalescence. Even though the mechanism of ductile failure is the same, the load carrying capacity predicted, for the same initial void volume fraction...

  1. Uroflowmetry in neurologically normal children with voiding disorders

    DEFF Research Database (Denmark)

    Jensen, K M; Nielsen, K.K.; Kristensen, E S

    1985-01-01

    of neurological deficits underwent a complete diagnostic program including intravenous urography, voiding cystography and cystoscopy as well as spontaneous uroflowmetry, cystometry-emg and pressure-flow-emg study. The incidence of dyssynergia was 22%. However, neither the flow curve pattern nor single flow...... variables were able to identify children with dyssynergia. Consequently uroflowmetry seems inefficient in the screening for dyssynergia in neurological normal children with voiding disorders in the absence of anatomical bladder outlet obstruction....

  2. A variational void coalescence model for ductile metals

    KAUST Repository

    Siddiq, Amir

    2011-08-17

    We present a variational void coalescence model that includes all the essential ingredients of failure in ductile porous metals. The model is an extension of the variational void growth model by Weinberg et al. (Comput Mech 37:142-152, 2006). The extended model contains all the deformation phases in ductile porous materials, i.e. elastic deformation, plastic deformation including deviatoric and volumetric (void growth) plasticity followed by damage initiation and evolution due to void coalescence. Parametric studies have been performed to assess the model\\'s dependence on the different input parameters. The model is then validated against uniaxial loading experiments for different materials. We finally show the model\\'s ability to predict the damage mechanisms and fracture surface profile of a notched round bar under tension as observed in experiments. © Springer-Verlag 2011.

  3. Redshift-space distortions around voids

    Science.gov (United States)

    Cai, Yan-Chuan; Taylor, Andy; Peacock, John A.; Padilla, Nelson

    2016-11-01

    We have derived estimators for the linear growth rate of density fluctuations using the cross-correlation function (CCF) of voids and haloes in redshift space. In linear theory, this CCF contains only monopole and quadrupole terms. At scales greater than the void radius, linear theory is a good match to voids traced out by haloes; small-scale random velocities are unimportant at these radii, only tending to cause small and often negligible elongation of the CCF near its origin. By extracting the monopole and quadrupole from the CCF, we measure the linear growth rate without prior knowledge of the void profile or velocity dispersion. We recover the linear growth parameter β to 9 per cent precision from an effective volume of 3( h-1Gpc)3 using voids with radius >25 h-1Mpc. Smaller voids are predominantly sub-voids, which may be more sensitive to the random velocity dispersion; they introduce noise and do not help to improve measurements. Adding velocity dispersion as a free parameter allows us to use information at radii as small as half of the void radius. The precision on β is reduced to 5 per cent. Voids show diverse shapes in redshift space, and can appear either elongated or flattened along the line of sight. This can be explained by the competing amplitudes of the local density contrast, plus the radial velocity profile and its gradient. The distortion pattern is therefore determined solely by the void profile and is different for void-in-cloud and void-in-void. This diversity of redshift-space void morphology complicates measurements of the Alcock-Paczynski effect using voids.

  4. Size-Effects in Void Growth

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof

    2005-01-01

    The size-effect on ductile void growth in metals is investigated. The analysis is based on unit cell models both of arrays of cylindrical voids under plane strain deformation, as well as arrays of spherical voids using an axisymmetric model. A recent finite strain generalization of two higher order...... models. This increased resistance to void growth, due to gradient hardening, is accompanied by an increase in the overall strength for the material. Furthermore, for increasing initial void volume fraction, it is shown that the effect of gradients becomes more important to the overall response but less...

  5. SPECTROSCOPIC STUDIES OF STRUCTURE, DYNAMICS AND REACTIVITY IN IONIC LIQUIDS.

    Energy Technology Data Exchange (ETDEWEB)

    WISHART,J.F.

    2007-11-30

    Ionic liquids (ILs) are a rapidly expanding family of condensed-phase media with important applications in energy production, nuclear fuel and waste processing, improving the efficiency and safety of industrial chemical processes, and pollution prevention. ILs are generally nonvolatile, noncombustible, highly conductive, recyclable and capable of dissolving a wide variety of materials. They are finding new uses in chemical synthesis, catalysis, separations chemistry, electrochemistry and other areas. Ionic liquids have dramatically different properties compared to conventional molecular solvents, and they provide a new and unusual environment to test our theoretical understanding of charge transfer and other reactions. We are interested in how IL properties influence physical and dynamical processes that determine the stability and lifetimes of reactive intermediates and thereby affect the courses of chemical reactions and product distributions. Successful use of ionic liquids in radiation-filled environments, where their safety advantages could be significant, requires an understanding of ionic liquid radiation chemistry. For example, characterizing the primary steps of IL radiolysis will reveal radiolytic degradation pathways and suggest ways to prevent them or mitigate their effects on the properties of the material. An understanding of ionic liquid radiation chemistry will also facilitate pulse radiolysis studies of general chemical reactivity in ILs, which will aid in the development of applications listed above. Very early in our radiolysis studies it became evident that slow solvation dynamics of the excess electron in ILs (which vary over a wide viscosity range) increases the importance of pre-solvated electron reactivity and consequently alters product distributions. Parallel studies of IL solvation phenomena using coumarin-153 dynamic Stokes shifts and polarization anisotropy decay rates are done to compare with electron solvation studies and to evaluate

  6. DFT study on structure, electronic properties, and reactivity of cis ...

    Indian Academy of Sciences (India)

    DFT global chemical reactivity descriptors (chemical hardness, total energy, electronic chemical potential, and electrophilicity) are calculated for the isomers and used to predict their relative stability and reactivity. The chemical reactivity indices are found to be related to the bond angle defined by the cis carbonyls and the ...

  7. Synthesis and Characterization of Organotin Containing Copolymers: Reactivity Ratio Studies

    Directory of Open Access Journals (Sweden)

    Mohamed H. El-Newehy

    2010-03-01

    Full Text Available Organotin monomers containing dibutyltin groups – dibutyltin citraconate (DBTC as a new monomer and dibutyltin maleate (DBTM – were synthesized. Free radical copolymerizations of the organotin monomers with styrene (ST and butyl acrylate (BA were performed. The overall conversion was kept low (≤15% wt/wt for all studied samples and the copolymers composition was determined from tin analysis using the Gillman and Rosenberg method. The reactivity ratios were calculated from the copolymer composition using the Fineman-Ross (FR method. The synthesized monomers were characterized by elemental analysis, 1H-, 13C-NMR and FTIR spectroscopy.

  8. Air void structure and frost resistance

    DEFF Research Database (Denmark)

    Hasholt, Marianne Tange

    2014-01-01

    are conducted. Results were not originally presented in a way, which made comparison possible. Here the amount of scaled material is depicted as function of air voids parameters: total air content, specific surface, spacing factor, and total surface area of air voids. The total surface area of air voids...... is proportional to the product of total air content and specific surface. In all 4 cases, the conclusion is concurrent that the parameter of total surface area of air voids performs equally well or better than the spacing factor when linking air void characteristics to frost resistance (salt frost scaling...... will take place in the air void, being feed from the capillary, but without pressure build-up in the capillary. If the capillary is not connected to an air void, ice formation will take place in the capillary pore, where it can generate substantial pressure. Like this, frost resistance depends...

  9. Nocturia: The circadian voiding disorder

    Directory of Open Access Journals (Sweden)

    Jin Wook Kim

    2016-05-01

    Full Text Available Nocturia is a prevalent condition of waking to void during the night. The concept of nocturia has evolved from being a symptomatic aspect of disease associated with the prostate or bladder to a form of lower urinary tract disorder. However, recent advances in circadian biology and sleep science suggest that it might be important to consider nocturia as a form of circadian dysfunction. In the current review, nocturia is reexamined with an introduction to sleep disorders and recent findings in circadian biology in an attempt to highlight the importance of rediscovering nocturia as a problem of chronobiology.

  10. Constitutive modeling of rate dependence and microinertia effects in porous-plastic materials with multi-sized voids (MSVs)

    KAUST Repository

    Liu, Jinxing

    2012-11-27

    Micro-voids of varying sizes exist in most metals and alloys. Both experiments and numerical studies have demonstrated the critical influence of initial void sizes on void growth. The classical Gurson-Tvergaard-Needleman model summarizes the influence of voids with a single parameter, namely the void-volume fraction, excluding any possible effects of the void-size distribution. We extend our newly proposed model including the multi-sized void (MSV) effect and the void-interaction effect for the capability of working for both moderate and high loading rate cases, where either rate dependence or microinertia becomes considerable or even dominant. Parametric studies show that the MSV-related competitive mechanism among void growth leads to the dependence of the void growth rate on void size, which directly influences the void\\'s contribution to the total energy composition. We finally show that the stress-strain constitutive behavior is also affected by this MSV-related competitive mechanism. The stabilizing effect due to rate sensitivity and microinertia is emphasized. © 2013 IOP Publishing Ltd.

  11. Functionalized molecules studied by STM: motion, switching and reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Grill, Leonhard [Institut fuer Experimentalphysik, Freie Universitaet Berlin, Arnimallee 14, 14195 Berlin (Germany)

    2008-02-06

    Functionalized molecules represent the central issue of molecular nanotechnology. Scanning tunnelling microscopy (STM) is a powerful method to investigate such molecules, because it allows us to image them with sub-molecular resolution when adsorbed on a surface and can be used at the same time as a tool to manipulate single molecules in a controlled way. Such studies permit deep insight into the conformational, mechanical and electronic structure and thus functionalities of the molecules. In this review, recent experiments on specially designed molecules, acting as model systems for molecular nanotechnology, are reviewed. The presented studies focus on key functionalities: lateral rolling and hopping motion on a supporting surface, the switching behaviour of azobenzene derivatives by using the STM tip and the controlled reactivity of molecular side groups, which enable the formation of covalently bound molecular nanoarchitectures. (topical review)

  12. Cosmology with void-galaxy correlations.

    Science.gov (United States)

    Hamaus, Nico; Wandelt, Benjamin D; Sutter, P M; Lavaux, Guilhem; Warren, Michael S

    2014-01-31

    Galaxy bias, the unknown relationship between the clustering of galaxies and the underlying dark matter density field is a major hurdle for cosmological inference from large-scale structure. While traditional analyses focus on the absolute clustering amplitude of high-density regions mapped out by galaxy surveys, we propose a relative measurement that compares those to the underdense regions, cosmic voids. On the basis of realistic mock catalogs we demonstrate that cross correlating galaxies and voids opens up the possibility to calibrate galaxy bias and to define a static ruler thanks to the observable geometric nature of voids. We illustrate how the clustering of voids is related to mass compensation and show that volume-exclusion significantly reduces the degree of stochasticity in their spatial distribution. Extracting the spherically averaged distribution of galaxies inside voids from their cross correlations reveals a remarkable concordance with the mass-density profile of voids.

  13. Theoretical study on the reactivity of sulfate species with hydrocarbons

    Science.gov (United States)

    Ma, Q.; Ellis, G.S.; Amrani, A.; Zhang, T.; Tang, Y.

    2008-01-01

    The abiotic, thermochemically controlled reduction of sulfate to hydrogen sulfide coupled with the oxidation of hydrocarbons, is termed thermochemical sulfate reduction (TSR), and is an important alteration process that affects petroleum accumulations in nature. Although TSR is commonly observed in high-temperature carbonate reservoirs, it has proven difficult to simulate in the laboratory under conditions resembling nature. The present study was designed to evaluate the relative reactivities of various sulfate species in order to provide greater insight into the mechanism of TSR and potentially to fill the gap between laboratory experimental data and geological observations. Accordingly, quantum mechanics density functional theory (DFT) was used to determine the activation energy required to reach a potential transition state for various aqueous systems involving simple hydrocarbons and different sulfate species. The entire reaction process that results in the reduction of sulfate to sulfide is far too complex to be modeled entirely; therefore, we examined what is believed to be the rate limiting step, namely, the reduction of sulfate S(VI) to sulfite S(IV). The results of the study show that water-solvated sulfate anions SO42 - are very stable due to their symmetrical molecular structure and spherical electronic distributions. Consequently, in the absence of catalysis, the reactivity of SO42 - is expected to be extremely low. However, both the protonation of sulfate to form bisulfate anions (HSO4-) and the formation of metal-sulfate contact ion-pairs could effectively destabilize the sulfate molecular structure, thereby making it more reactive. Previous reports of experimental simulations of TSR generally have involved the use of acidic solutions that contain elevated concentrations of HSO4- relative to SO42 -. However, in formation waters typically encountered in petroleum reservoirs, the concentration of HSO4- is likely to be significantly lower than the levels

  14. Evaluation of the Air Void Analyzer

    Science.gov (United States)

    2013-07-01

    glycerin -based blue viscous release fluid. This version was first used in June 1994 for testing in Michigan, Wisconsin, Texas, and Iowa; and the...sample of mortar is obtained from concrete, it is injected into the base of the column with the glycerin -based blue release fluid, and the mortar sample...separation when measuring. Void rise speeds are reduced in the higher viscosity glycerin solution. Once the voids are freed from the mortar, the voids

  15. Critical Void Volume Fraction fc at Void Coalescence for S235JR Steel at Low Initial Stress Triaxiality

    Science.gov (United States)

    Grzegorz Kossakowski, Paweł; Wciślik, Wiktor

    2017-10-01

    The paper is concerned with the nucleation, growth and coalescence of microdefects in the form of voids in S235JR steel. The material is known to be one of the basic steel grades commonly used in the construction industry. The theory and methods of damage mechanics were applied to determine and describe the failure mechanisms that occur when the material undergoes deformation. Until now, engineers have generally employed the Gurson-Tvergaard- Needleman model. This material model based on damage mechanics is well suited to define and analyze failure processes taking place in the microstructure of S235JR steel. It is particularly important to determine the critical void volume fraction fc , which is one of the basic parameters of the Gurson-Tvergaard-Needleman material model. As the critical void volume fraction fc refers to the failure stage, it is determined from the data collected for the void coalescence phase. A case of multi-axial stresses is considered taking into account the effects of spatial stress state. In this study, the parameter of stress triaxiality η was used to describe the failure phenomena. Cylindrical tensile specimens with a circumferential notch were analysed to obtain low values of initial stress triaxiality (η = 0.556 of the range) in order to determine the critical void volume fraction fc . It is essential to emphasize how unique the method applied is and how different it is from the other more common methods involving parameter calibration, i.e. curve-fitting methods. The critical void volume fraction fc at void coalescence was established through digital image analysis of surfaces of S235JR steel, which involved studying real, physical results obtained directly from the material tested.

  16. Use of double and triple-ion irradiation to study the influence of high levels of helium and hydrogen on void swelling of 8–12% Cr ferritic-martensitic steels

    Energy Technology Data Exchange (ETDEWEB)

    Kupriiyanova, Y.E., E-mail: fomenkoj@kipt.kharkov.ua [National Science Centre Kharkov Institute of Physics and Technology, 1, Akademicheskaya St., Kharkov, 61108 (Ukraine); Bryk, V.V.; Borodin, O.V.; Kalchenko, A.S.; Voyevodin, V.N.; Tolstolutskaya, G.D. [National Science Centre Kharkov Institute of Physics and Technology, 1, Akademicheskaya St., Kharkov, 61108 (Ukraine); Garner, F.A. [Radiation Effects Consulting, Richland, WA 99354 (United States)

    2016-01-15

    In accelerator-driven spallation (ADS) devices, some of the structural materials will be exposed to intense fluxes of very high energy protons and neutrons, producing not only displacement damage, but very high levels of helium and hydrogen. Unlike fission flux-spectra where most helium and hydrogen are generated by transmutation in nickel and only secondarily in iron or chromium, gas production in ADS flux-spectra are rather insensitive to alloy composition, such that Fe–Cr base ferritic alloys also generate very large gas levels. While ferritic alloys are known to swell less than austenitic alloys in fission spectra, there is a concern that high gas levels in fusion and especially ADS facilities may strongly accelerate void swelling in ferritic alloys. In this study of void swelling in response to helium and hydrogen generation, irradiation was conducted on three ferritic-martensitic steels using the Electrostatic Accelerator with External Injector (ESUVI) facility that can easily produce any combination of helium to dpa and/or hydrogen to dpa ratios. Irradiation was conducted under single, dual and triple beam modes using 1.8 MeV Cr{sup +3}, 40 keV He{sup +}, and 20 keV H{sup +}. In the first part of this study we investigated the response of dual-phase EP-450 to variations in He/dpa and H/dpa ratio, focusing first on dual ion studies and then triple ion studies, showing that there is a diminishing influence on swelling with increasing total gas content. In the second part we investigated the relative response of three alloys spanning a range of starting microstructure and composition. In addition to observing various synergisms between He and H, the most important conclusion was that the tempered martensite phase, known to lag behind the ferrite phase in swelling in the absence of gases, loses much of its resistance to void nucleation when irradiated at large gas/dpa levels.

  17. Toilet training method is not related to dysfunctional voiding.

    Science.gov (United States)

    Colaco, Marc; Johnson, Kelly; Schneider, Dona; Barone, Joseph

    2013-01-01

    Toilet training is an important marker of physical and psychosocial development, but the best strategy for implementing training is still unknown. The purpose of this study is to compare dysfunctional voiding outcomes for 2 common toilet training strategies: parent-oriented training and child-oriented training. This study was completed using a case-control design, with participants between the ages of 4 and 12 years. All participants were asked to complete questionnaires related to demographics and toilet training method. Results were then analyzed between cases and controls. In all, 215 patients with a mean age 7.76 years participated in this study. Cases and controls showed no significant difference for demographic measures and socioeconomic status. Furthermore, there was no significant difference in dysfunctional voiding between toilet training methods. Toilet training method does not seem to have any long-term effect on dysfunctional voiding. As such, clinicians should advise parents that both methods are acceptable.

  18. Reactive system verification case study: Fault-tolerant transputer communication

    Science.gov (United States)

    Crane, D. Francis; Hamory, Philip J.

    1993-01-01

    A reactive program is one which engages in an ongoing interaction with its environment. A system which is controlled by an embedded reactive program is called a reactive system. Examples of reactive systems are aircraft flight management systems, bank automatic teller machine (ATM) networks, airline reservation systems, and computer operating systems. Reactive systems are often naturally modeled (for logical design purposes) as a composition of autonomous processes which progress concurrently and which communicate to share information and/or to coordinate activities. Formal (i.e., mathematical) frameworks for system verification are tools used to increase the users' confidence that a system design satisfies its specification. A framework for reactive system verification includes formal languages for system modeling and for behavior specification and decision procedures and/or proof-systems for verifying that the system model satisfies the system specifications. Using the Ostroff framework for reactive system verification, an approach to achieving fault-tolerant communication between transputers was shown to be effective. The key components of the design, the decoupler processes, may be viewed as discrete-event-controllers introduced to constrain system behavior such that system specifications are satisfied. The Ostroff framework was also effective. The expressiveness of the modeling language permitted construction of a faithful model of the transputer network. The relevant specifications were readily expressed in the specification language. The set of decision procedures provided was adequate to verify the specifications of interest. The need for improved support for system behavior visualization is emphasized.

  19. Partial discharges in ellipsoidal and spheroidal voids

    DEFF Research Database (Denmark)

    Crichton, George C; Karlsson, P. W.; Pedersen, Aage

    1989-01-01

    Transients associated with partial discharges in voids can be described in terms of the charges induced on the terminal electrodes of the system. The relationship between the induced charge and the properties which are usually measured is discussed. The method is illustrated by applying it to a s...... it to a spheroidal void located in a simple disk-type spacer...

  20. International business responses to institutional voids

    NARCIS (Netherlands)

    Doh, J.; Rodrigues, S.; Saka-Helmhout, A.U.; Makhija, M.

    2017-01-01

    For nearly two decades, scholars in international business and management have explored the implications of institutional voids for firm strategy and structure. Although institutional voids offer both opportunities and challenges, they have largely been associated with firms’ efforts to avoid or

  1. Granular Eruptions: Void Collapse and Jet Formation

    NARCIS (Netherlands)

    Mikkelsen, R.; Versluis, Andreas Michel; Koene, Elmer; Bruggert, Gert-Wim; van der Meer, Roger M.; van der Weele, J.P.; Lohse, Detlef

    2002-01-01

    Upon impact, sand is blown away in all directions, forming a splash. The ball digs a cylindrical void in the sand and the jet is formed when this void collapses: The focused sand pressure pushes the jet straight up into the air. When the jet comes down again, it breaks up into fragments, i.e.,

  2. The dipole moment of a wall-charged void in a bulk dielectric

    DEFF Research Database (Denmark)

    McAllister, Iain Wilson

    1993-01-01

    The dipole moment of a wall-charged void is examined with reference to the spatial extent of the surface charge density σ and the distribution of this charge. The salient factors influencing the void dipole moment are also examined. From a study of spherical voids, it is shown that, although the σ......-distribution influences the dipole moment, the spatial extent of σ has a greater influence. This behavior is not unexpected. For a void of fixed dimensions, the smaller the charged surface area, the greater is the charges, and thus the greater the dipole moment...

  3. Metallicities of Galaxies in the Lynx-Cancer Void

    Science.gov (United States)

    Kniazev, A.; Pustilnik, S.; Tepliakova, A.; Burenkov, A.

    Does the void environment have a sizable effect on the evolution of dwarf galaxies? If yes, the best probes should be the most fragile least massive dwarfs. We compiled a sample of about one hundred dwarfs with MB in the range -12to -18 mag, falling within the nearby Lynx-Cancer void. The goal is to study their evolutionary parameters - gas metallicity and gas mass-fraction, and to address the epoch of the first substantial episode of Star Formation. Here we present and discuss the results of O/H measurements in 38 void galaxies, among which several of the most metal-poor galaxies are found with an oxygen abundance of 12 + log(O/H) = 7. 12-7.3 dex.

  4. Internal Nano Voids in Yttria-Stabilised Zirconia (YSZ Powder

    Directory of Open Access Journals (Sweden)

    Chen Barad

    2017-12-01

    Full Text Available Porous yttria-stabilised zirconia ceramics have been gaining popularity throughout the years in various fields, such as energy, environment, medicine, etc. Although yttria-stabilised zirconia is a well-studied material, voided yttria-stabilised zirconia powder particles have not been demonstrated yet, and might play an important role in future technology developments. A sol-gel synthesis accompanied by a freeze-drying process is currently being proposed as a method of obtaining sponge-like nano morphology of embedded faceted voids inside yttria-stabilised zirconia particles. The results rely on a freeze-drying stage as an effective and simple method for generating nano-voided yttria-stabilised zirconia particles without the use of template-assisted additives.

  5. Pores and Void in Asclepiades' Physical Theory.

    Science.gov (United States)

    Leith, David

    2012-01-01

    This paper examines a fundamental, though relatively understudied, aspect of the physical theory of the physician Asclepiades of Bithynia, namely his doctrine of pores. My principal thesis is that this doctrine is dependent on a conception of void taken directly from Epicurean physics. The paper falls into two parts: the first half addresses the evidence for the presence of void in Asclepiades' theory, and concludes that his conception of void was basically that of Epicurus; the second half focuses on the precise nature of Asclepiadean pores, and seeks to show that they represent void interstices between the primary particles of matter which are the constituents of the human body, and are thus exactly analogous to the void interstices between atoms within solid objects in Epicurus' theory.

  6. Basic study on dynamic reactive-power control method with PV output prediction for solar inverter

    Directory of Open Access Journals (Sweden)

    Ryunosuke Miyoshi

    2016-01-01

    Full Text Available To effectively utilize a photovoltaic (PV system, reactive-power control methods for solar inverters have been considered. Among the various methods, the constant-voltage control outputs less reactive power compared with the other methods. We have developed a constant-voltage control to reduce the reactive-power output. However, the developed constant-voltage control still outputs unnecessary reactive power because the control parameter is constant in every waveform of the PV output. To reduce the reactive-power output, we propose a dynamic reactive-power control method with a PV output prediction. In the proposed method, the control parameter is varied according to the properties of the predicted PV waveform. In this study, we performed numerical simulations using a distribution system model, and we confirmed that the proposed method reduces the reactive-power output within the voltage constraint.

  7. Warmth Elevating the Depths: Shallower Voids with Warm Dark Matter

    OpenAIRE

    Yang, Lin F.; Neyrinck, Mark C.; Aragon-Calvo, Miguel A.; Falck, Bridget; Silk, Joseph

    2014-01-01

    Warm dark matter (WDM) has been proposed as an alternative to cold dark matter (CDM), to resolve issues such as the apparent lack of satellites around the Milky Way. Even if WDM is not the answer to observational issues, it is essential to constrain the nature of the dark matter. The effect of WDM on haloes has been extensively studied, but the small-scale initial smoothing in WDM also affects the present-day cosmic web and voids. It suppresses the cosmic "sub-web" inside voids, and the forma...

  8. Formation of Voids from Negative Density Perturbations

    Science.gov (United States)

    de Araujo, J. C. N.; Opher, R.

    1990-11-01

    RESUMEN. Se estudia la formaci6n de huecos a partir de un espectro negativo de perturbaciones, tomando en cuenta la expansi6n del Universo, arrastre por fotones, enfriamiento por fotones, fotoionizaci6n, ioniza- ci6n colisional, enfriamiento Lyman a y la formaci6n y enfriamiento de moleculas H2. Nuestros resultados predicen la existencia de regiones 1/10 de Ia densidad promedio para regiones de masa lO - 1O10M . ABSTRACT. In the present paer we study the formation of voids from a negative spectrum of perturbations taking into account the expansion of the Universe, photon-drag, photon-cooling, photoionization, collisional ionization, Lyman a cooling and the formation and cooling of 112 molecules. Our results predict the existence of regions 1/10 the average density for regions of mass 1O - 1O10M@ : CLUSTERS-GALAXIES - COSMOLOGY

  9. VIDE: The Void IDentification and Examination toolkit

    Science.gov (United States)

    Sutter, P. M.; Lavaux, G.; Hamaus, N.; Pisani, A.; Wandelt, B. D.; Warren, M.; Villaescusa-Navarro, F.; Zivick, P.; Mao, Q.; Thompson, B. B.

    2015-03-01

    We present VIDE, the Void IDentification and Examination toolkit, an open-source Python/C++ code for finding cosmic voids in galaxy redshift surveys and N -body simulations, characterizing their properties, and providing a platform for more detailed analysis. At its core, VIDE uses a substantially enhanced version of ZOBOV (Neyinck 2008) to calculate a Voronoi tessellation for estimating the density field and performing a watershed transform to construct voids. Additionally, VIDE provides significant functionality for both pre- and post-processing: for example, VIDE can work with volume- or magnitude-limited galaxy samples with arbitrary survey geometries, or dark matter particles or halo catalogs in a variety of common formats. It can also randomly subsample inputs and includes a Halo Occupation Distribution model for constructing mock galaxy populations. VIDE uses the watershed levels to place voids in a hierarchical tree, outputs a summary of void properties in plain ASCII, and provides a Python API to perform many analysis tasks, such as loading and manipulating void catalogs and particle members, filtering, plotting, computing clustering statistics, stacking, comparing catalogs, and fitting density profiles. While centered around ZOBOV, the toolkit is designed to be as modular as possible and accommodate other void finders. VIDE has been in development for several years and has already been used to produce a wealth of results, which we summarize in this work to highlight the capabilities of the toolkit. VIDE is publicly available at

  10. Practical statistics for the voids between galaxies

    Directory of Open Access Journals (Sweden)

    Zaninetti L.

    2010-01-01

    Full Text Available The voids between galaxies are identified with the volumes of the Poisson Voronoi tessellation. Two new survival functions for the apparent radii of voids are derived. The sectional normalized area of the Poisson Voronoi tessellation is modelled by the Kiang function and by the exponential function. Two new survival functions with equivalent sectional radius are therefore derived; they represent an alternative to the survival function of voids between galaxies as given by the self-similar distribution. The spatial appearance of slices of the 2dF Galaxy Redshift Survey is simulated.

  11. Practical Statistics for the Voids Between Galaxies

    Directory of Open Access Journals (Sweden)

    Zaninetti, L.

    2010-12-01

    Full Text Available The voids between galaxies are identified withthe volumes of the Poisson Voronoi tessellation.Two new survival functions for the apparent radii of voids are derived. The sectional normalized area ofthe Poisson Voronoi tessellation is modelledby the Kiang function and by the exponential function. Two new survival functions with equivalent sectional radius are therefore derived; they represent an alternative to the survival function of voids between galaxies as given by the self-similar distribution. The spatial appearance of slices of the 2dF Galaxy Redshift Survey is simulated.

  12. The Aspen–Amsterdam Void Finder Comparison Project

    NARCIS (Netherlands)

    Colberg, J¨org M.; Pearce, Frazer; Foster, Caroline; Platen, Erwin; Brunino, Riccardo; Neyrinck, Mark; Basilakos, Spyros; Faira, Anthony; Feldman, Hume; Gottlöber, Stefan; Hahn, Oliver; Hoyle, Fiona; M¨uller, V.; Nelson, Lorne; Plionis, Manolis; Porciani, Cristiano; Shandarin, Sergei; Vogeley, Michael S.; Weygaert, Rien van de

    2008-01-01

    Despite a history that dates back at least a quarter of a century studies of voids in the large–scale structure of the Universe are bedevilled by a major problem: there exist a large number of quite different void–finding algorithms, a fact that has so far got in the way of groups comparing their

  13. The cosmic web in CosmoGrid void regions

    NARCIS (Netherlands)

    Rieder, Steven; van de Weygaert, Rien; Cautun, Marius; Beygu, Burcu; Portegies Zwart, Simon

    2016-01-01

    We study the formation and evolution of the cosmic web, using the high-resolution CosmoGrid ΛCDM simulation. In particular, we investigate the evolution of the large-scale structure around void halo groups, and compare this to observations of the VGS-31 galaxy group, which consists of three

  14. Comparative study of C-Reactive Protein and other biochemical ...

    African Journals Online (AJOL)

    Serum levels of C-reactive proteins (CRP), Alanine aminotransferase (ALT), Aspartate aminotransferase (AST), total protein, albumin and globulins were investigated using high sensitivity Immunoturbidometric and colorimetric techniques in individuals with hepatitis (n=50), Malaria (n=50) and 40 control subjects in age ...

  15. Brachial artery reactivity in patients with severe sepsis: an observational study

    OpenAIRE

    Wexler, Orren; M Morgan, Mary Anne; Gough, Michael S.; Steinmetz, Sherry D; Mack, Cynthia M.; Darling, Denise C.; Doolin, Kathleen P.; Apostolakos, Michael J.; Graves, Brian T; Frampton, Mark W.; Chen, Xucai; Pietropaoli, Anthony P.

    2012-01-01

    Introduction Ultrasound measurements of brachial artery reactivity in response to stagnant ischemia provide estimates of microvascular function and conduit artery endothelial function. We hypothesized that brachial artery reactivity would independently predict severe sepsis and severe sepsis mortality. Methods This was a combined case-control and prospective cohort study. We measured brachial artery reactivity in 95 severe sepsis patients admitted to the medical and surgical intensive care un...

  16. Size-effects at a crack-tip interacting with a number of voids

    DEFF Research Database (Denmark)

    Tvergaard, Viggo; Niordson, Christian Frithiof

    2008-01-01

    A strain gradient plasticity theory is used to analyse the growth of discretely represented voids in front of a blunting crack tip, in order to study the influence of size effects on two competing mechanisms of crack growth. For a very small void volume fraction the crack tip tends to interact...

  17. Propagation of Love waves in an elastic layer with void pores

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    of longitudinal and shear waves in void media and came to the conclusion that there may be two wave fronts for longitudinal waves. Deyet al(1993) discussed the propagation of torsional surface waves in an elastic medium with void pores. The influence of local irregularities on propagation of Love waves has been studied ...

  18. Plane waves in a rotating generalized thermo-elastic solid with voids ...

    African Journals Online (AJOL)

    Propagation of plane waves in a rotating thermo-elastic solid with voids has been studied. The theory for thermo-elastic materials with voids developed by Iesan in the context of thermo- elastic theory of Lord and Shulman has been employed for mathematical treatment. It has been found that there exist one transverse wave ...

  19. LOG-NORMAL DISTRIBUTION OF COSMIC VOIDS IN SIMULATIONS AND MOCKS

    Energy Technology Data Exchange (ETDEWEB)

    Russell, E.; Pycke, J.-R., E-mail: er111@nyu.edu, E-mail: jrp15@nyu.edu [Division of Science and Mathematics, New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi (United Arab Emirates)

    2017-01-20

    Following up on previous studies, we complete here a full analysis of the void size distributions of the Cosmic Void Catalog based on three different simulation and mock catalogs: dark matter (DM), haloes, and galaxies. Based on this analysis, we attempt to answer two questions: Is a three-parameter log-normal distribution a good candidate to satisfy the void size distributions obtained from different types of environments? Is there a direct relation between the shape parameters of the void size distribution and the environmental effects? In an attempt to answer these questions, we find here that all void size distributions of these data samples satisfy the three-parameter log-normal distribution whether the environment is dominated by DM, haloes, or galaxies. In addition, the shape parameters of the three-parameter log-normal void size distribution seem highly affected by environment, particularly existing substructures. Therefore, we show two quantitative relations given by linear equations between the skewness and the maximum tree depth, and between the variance of the void size distribution and the maximum tree depth, directly from the simulated data. In addition to this, we find that the percentage of voids with nonzero central density in the data sets has a critical importance. If the number of voids with nonzero central density reaches ≥3.84% in a simulation/mock sample, then a second population is observed in the void size distributions. This second population emerges as a second peak in the log-normal void size distribution at larger radius.

  20. Study of hysteresis behavior in reactive sputtering of cylindrical magnetron plasma

    Science.gov (United States)

    Kakati, H.; M. Borah, S.

    2015-12-01

    In order to make sufficient use of reactive cylindrical magnetron plasma for depositing compound thin films, it is necessary to characterize the hysteresis behavior of the discharge. Cylindrical magnetron plasmas with different targets namely titanium and aluminium are studied in an argon/oxygen and an argon/nitrogen gas environment respectively. The aluminium and titanium emission lines are observed at different flows of reactive gases. The emission intensity is found to decrease with the increase of the reactive gas flow rate. The hysteresis behavior of reactive cylindrical magnetron plasma is studied by determining the variation of discharge voltage with increasing and then reducing the flow rate of reactive gas, while keeping the discharge current constant at 100 mA. Distinct hysteresis is found to be formed for the aluminium target and reactive gas oxygen. For aluminium/nitrogen, titanium/oxygen and titanium/nitrogen, there is also an indication of the formation of hysteresis; however, the characteristics of variation from metallic to reactive mode are different in different cases. The hysteresis behaviors are different for aluminium and titanium targets with the oxygen and nitrogen reactive gases, signifying the difference in reactivity between them. The effects of the argon flow rate and magnetic field on the hysteresis are studied and explained. Project supported by the Department of Science and Technology, Government of India and Council of Scientific and Industrial Research, India.

  1. Molecular Gas and Star Formation in Void Galaxies

    Science.gov (United States)

    Das, M.; Saito, T.; Iono, D.; Honey, M.; Ramya, S.

    2016-10-01

    We present the detection of molecular gas using CO(1-0) line emission and followup Hα imaging observations of galaxies located in nearby voids. The CO(1-0) observations were done using the 45m telescope of the Nobeyama Radio Observatory (NRO) and the optical observations were done using the Himalayan Chandra Telescope (HCT). Although void galaxies lie in the most underdense parts of our universe, a significant fraction of them are gas rich, spiral galaxies that show signatures of ongoing star formation. Not much is known about their cold gas content or star formation properties. In this study we searched for molecular gas in five void galaxies using the NRO. The galaxies were selected based on their relatively higher IRAS fluxes or Hα line luminosities. CO(1-0) emission was detected in four galaxies and the derived molecular gas masses lie between (1 - 8)×109 M⊙. The Hα imaging observations of three galaxies detected in CO emission indicates ongoing star formation and the derived star formation rates vary between from 0.2 - 1.0 M7odot; yr -1, which is similar to that observed in local galaxies. Our study shows that although void galaxies reside in underdense regions, their disks may contain molecular gas and have star formation rates similar to galaxies in denser environments.

  2. Topology optimization with flexible void area

    DEFF Research Database (Denmark)

    Clausen, Anders; Aage, Niels; Sigmund, Ole

    2014-01-01

    This paper presents a methodology for including fixed-area flexible void domains into the minimum compliance topology optimization problem. As opposed to the standard passive elements approach of rigidly specifying void areas within the design domain, the suggested approach allows these areas...... to be flexibly reshaped and repositioned subject to penalization on their moments of inertia, the positions of their centers of mass, and their shapes. The flexible void areas are introduced through a second, discrete design variable field, using the same discretization as the standard field of continuous...... density variables. The formulation is based on a combined approach: The primary sub-problem is to minimize compliance, subject to a volume constraint, with a secondary sub-problem of minimizing the disturbance from the flexible void areas. The design update is performed iteratively between the two...

  3. Neutron Imaging Calibration to Measure Void Fraction

    Energy Technology Data Exchange (ETDEWEB)

    Geoghegan, Patrick J [ORNL; Bilheux, Hassina Z [ORNL; Sharma, Vishaldeep [ORNL; Fricke, Brian A [ORNL

    2015-01-01

    Void fraction is an intuitive parameter that describes the fraction of vapor in a two-phase flow. It appears as a key variable in most heat transfer and pressure drop correlations used to design evaporating and condensing heat exchangers, as well as determining charge inventory in refrigeration systems. Void fraction measurement is not straightforward, however, and assumptions on the invasiveness of the measuring technique must be made. Neutron radiography or neutron imaging has the potential to be a truly non-invasive void fraction measuring technique but has until recently only offered qualitative descriptions of two-phase flow, in terms of flow maldistributions, for example. This paper describes the calibration approach necessary to employ neutron imaging to measure steady-state void fraction. Experiments were conducted at the High Flux Isotope Reactor (HFIR) Cold Guide 1D neutron imaging facility at Oak Ridge National Laboratory (ORNL), Oak Ridge, TN, USA.

  4. Void growth in metals: Atomistic calculations

    Energy Technology Data Exchange (ETDEWEB)

    Traiviratana, Sirirat [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 (United States); Bringa, Eduardo M. [Materials Science Department, Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States); Benson, David J. [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 (United States); Meyers, Marc A. [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, CA 92093 (United States); NanoEngineering, University of California, San Diego, La Jolla, CA 92093 (United States)], E-mail: mameyers@ucsd.edu

    2008-09-15

    Molecular dynamics simulations in monocrystalline and bicrystalline copper were carried out with LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator) to reveal void growth mechanisms. The specimens were subjected to tensile uniaxial strains; the results confirm that the emission of (shear) loops is the primary mechanism of void growth. It is observed that many of these shear loops develop along two slip planes (and not one, as previously thought), in a heretofore unidentified mechanism of cooperative growth. The emission of dislocations from voids is the first stage, and their reaction and interaction is the second stage. These loops, forming initially on different {l_brace}1 1 1{r_brace} planes, join at the intersection, if the Burgers vector of the dislocations is parallel to the intersection of two {l_brace}1 1 1{r_brace} planes: a <1 1 0> direction. Thus, the two dislocations cancel at the intersection and a biplanar shear loop is formed. The expansion of the loops and their cross slip leads to the severely work-hardened region surrounding a growing void. Calculations were carried out on voids with different sizes, and a size dependence of the stress threshold to emit dislocations was obtained by MD, in disagreement with the Gurson model which is scale independent. This disagreement is most marked for the nanometer sized voids. The scale dependence of the stress required to grow voids is interpreted in terms of the decreasing availability of optimally oriented shear planes and increased stress required to nucleate shear loops as the void size is reduced. The growth of voids simulated by MD is compared with the Cocks-Ashby constitutive model and significant agreement is found. The density of geometrically necessary dislocations as a function of void size is calculated based on the emission of shear loops and their outward propagation. Calculations are also carried out for a void at the interface between two grains to simulate polycrystalline

  5. Biofeedback therapy and dysfunctional voiding in children.

    Science.gov (United States)

    Duel, Barry P

    2003-04-01

    Dysfunctional voiding, a condition in which a neurologically intact child fails to relax the urinary sphincter during micturition, was first described in the 1970s. Clinically, these children have urinary incontinence and recurrent urinary tract infections. Biofeedback, through which the child is taught to relax the pelvic floor during voiding, has become an increasingly popular method of treatment. Many series, most retrospective, have shown biofeedback to be very effective in the treatment of this disorder.

  6. Voiding postponement in children-a systematic review.

    Science.gov (United States)

    von Gontard, Alexander; Niemczyk, Justine; Wagner, Catharina; Equit, Monika

    2016-08-01

    Voiding postponement (VP) has been defined as a habitual postponement of micturition using holding maneuvers. VP can represent both a symptom, as well as a condition. As divergent definitions are used internationally, the aim was to review the current state of knowledge on VP and provide recommendations for assessment, diagnosis and treatment. A Scopus and a Pubmed search was conducted, entering the terms 'voiding postponement' without any restrictions or specifications. Other publications relevant to the topic were added. VP can represent a symptom in healthy children. As a condition, VP in combination with nocturnal enuresis (NE) is a subtype of non-monosymptomatic NE. Most studies have focused on daytime urinary incontinence (DUI) with VP, or more aptly termed voiding postponement incontinence (VPI). It is a behaviorally defined syndrome, i.e., by the habitual deferral of micturition and DUI. VPI is associated with a low micturition frequency, urgency and behavioral problems. The most common comorbid disorder is oppositional defiant disorder (ODD). VP as a symptom and VPI as a condition should be differentiated. VPI is a common disorder with many associated problems and disorders. Urotherapy and timed voiding are the main treatment approaches. Due to the high rate of comorbid ODD, other forms of treatment, especially cognitive behavioral therapy, are often needed.

  7. Post-void residual urine under 150 ml does not exclude voiding dysfunction in women

    DEFF Research Database (Denmark)

    Khayyami, Yasmine; Klarskov, Niels; Lose, Gunnar

    2016-01-01

    INTRODUCTION AND HYPOTHESIS: It has been claimed that post-void residual urine (PVR) below 150 ml rules out voiding dysfunction in women with stress urinary incontinence (SUI) and provides license to perform sling surgery. The cut-off of 150 ml seems arbitrary, not evidence-based, and so we sought....... CONCLUSIONS: Patients with voiding dysfunction often have normal PVR and so PVR incontinence surgery....

  8. Parallel Void Thread in Long-Reach Ethernet Passive Optical Networks

    KAUST Repository

    Elrasad, Amr

    2015-06-25

    This work investigates void filling (idle periods) in long-reach Ethernet passive optical networks. We focus on reducing grant delays and hence reducing the average packet delay. We introduce a novel approach called parallel void thread (PVT), which allocates bandwidth grants during voids baseless of bandwidth requests. We introduce three different grant sizing schemes for PVT, namely void extension, count controlled batch void filling, and size controlled batch void filling. The proposed approaches canbe integrated with almost all of the previously reported dynamic bandwidth allocation schemes. Unlike other void filling schemes, PVT is less sensitive to the differential distance between optical network units and can work very well in the case of limited differential distances. We have analytically investigated the packet delay and derived a bound condition for PVT to outperform the other competitors. We support our work with extensive simulation study considering bursty traffic with long range dependence for both the single-class and differentiated services (DiffServ) scenarios. Numerical results show delay reduction up to 35% compared with the non-void filling scheme for the single-class scenario. For DiffServ traffic, PVT achieves delay reduction up to 80% for expedited forward traffic, 52% for assured forward traffic, and 56% for best effort traffic. © 2015 OSA.

  9. Linear redshift space distortions for cosmic voids based on galaxies in redshift space

    Science.gov (United States)

    Chuang, Chia-Hsun; Kitaura, Francisco-Shu; Liang, Yu; Font-Ribera, Andreu; Zhao, Cheng; McDonald, Patrick; Tao, Charling

    2017-03-01

    Cosmic voids found in galaxy surveys are defined based on the galaxy distribution in redshift space. We show that the large scale distribution of voids in redshift space traces the fluctuations in the dark matter density field δ(k) (in Fourier space with μ being the line of sight projected k-vector): δ_v^s(k) = (1 + β_v μ^2) b^s_v δ(k), with a beta factor that will be in general different than the one describing the distribution of galaxies. Only in case voids could be assumed to be quasi-local transformations of the linear (Gaussian) galaxy redshift space field, one gets equal beta factors β_v=β_g=f/b_g with f being the growth rate, and b_g, b^s_v being the galaxy and void bias on large scales defined in redshift space. Indeed, in our mock void catalogs we measure void beta factors being in good agreement with the galaxy one. Further work needs to be done to confirm the level of accuracy of the beta factor equality between voids and galaxies, but in general the void beta factor needs to be considered as a free parameter for RSD studies.

  10. Generation of Subsurface Voids, Incubation Effect, and Formation of Nanoparticles in Short Pulse Laser Interactions with Bulk Metal Targets in Liquid: Molecular Dynamics Study

    Science.gov (United States)

    2017-01-01

    The ability of short pulse laser ablation in liquids to produce clean colloidal nanoparticles and unusual surface morphology has been employed in a broad range of practical applications. In this paper, we report the results of large-scale molecular dynamics simulations aimed at revealing the key processes that control the surface morphology and nanoparticle size distributions by pulsed laser ablation in liquids. The simulations of bulk Ag targets irradiated in water are performed with an advanced computational model combining a coarse-grained representation of liquid environment and an atomistic description of laser interaction with metal targets. For the irradiation conditions that correspond to the spallation regime in vacuum, the simulations predict that the water environment can prevent the complete separation of the spalled layer from the target, leading to the formation of large subsurface voids stabilized by rapid cooling and solidification. The subsequent irradiation of the laser-modified surface is found to result in a more efficient ablation and nanoparticle generation, thus suggesting the possibility of the incubation effect in multipulse laser ablation in liquids. The simulations performed at higher laser fluences that correspond to the phase explosion regime in vacuum reveal the accumulation of the ablation plume at the interface with the water environment and the formation of a hot metal layer. The water in contact with the metal layer is brought to the supercritical state and provides an environment suitable for nucleation and growth of small metal nanoparticles from metal atoms emitted from the hot metal layer. The metal layer itself has limited stability and can readily disintegrate into large (tens of nanometers) nanoparticles. The layer disintegration is facilitated by the Rayleigh–Taylor instability of the interface between the higher density metal layer decelerated by the pressure from the lighter supercritical water. The nanoparticles

  11. Generation of Subsurface Voids, Incubation Effect, and Formation of Nanoparticles in Short Pulse Laser Interactions with Bulk Metal Targets in Liquid: Molecular Dynamics Study.

    Science.gov (United States)

    Shih, Cheng-Yu; Shugaev, Maxim V; Wu, Chengping; Zhigilei, Leonid V

    2017-08-03

    The ability of short pulse laser ablation in liquids to produce clean colloidal nanoparticles and unusual surface morphology has been employed in a broad range of practical applications. In this paper, we report the results of large-scale molecular dynamics simulations aimed at revealing the key processes that control the surface morphology and nanoparticle size distributions by pulsed laser ablation in liquids. The simulations of bulk Ag targets irradiated in water are performed with an advanced computational model combining a coarse-grained representation of liquid environment and an atomistic description of laser interaction with metal targets. For the irradiation conditions that correspond to the spallation regime in vacuum, the simulations predict that the water environment can prevent the complete separation of the spalled layer from the target, leading to the formation of large subsurface voids stabilized by rapid cooling and solidification. The subsequent irradiation of the laser-modified surface is found to result in a more efficient ablation and nanoparticle generation, thus suggesting the possibility of the incubation effect in multipulse laser ablation in liquids. The simulations performed at higher laser fluences that correspond to the phase explosion regime in vacuum reveal the accumulation of the ablation plume at the interface with the water environment and the formation of a hot metal layer. The water in contact with the metal layer is brought to the supercritical state and provides an environment suitable for nucleation and growth of small metal nanoparticles from metal atoms emitted from the hot metal layer. The metal layer itself has limited stability and can readily disintegrate into large (tens of nanometers) nanoparticles. The layer disintegration is facilitated by the Rayleigh-Taylor instability of the interface between the higher density metal layer decelerated by the pressure from the lighter supercritical water. The nanoparticles emerging

  12. Blind void filling in LR-EPONs: How efficient it can be?

    KAUST Repository

    Elrasad, Amr

    2015-07-01

    This work proposes a novel blind void (idle periods) filling in Long-Reach Ethernet Passive Optical Networks (LR-EPONs) namely Size Controlled Batch Void Filling (SCBVF). We emphasize on reducing grant delays and hence reducing the average packet delay. SCBVF delay reduction is achieved by early flushing data during the idle time periods (voids) between allocated grants. The proposed approach can be integrated with almost all of the previously reported dynamic bandwidth allocation schemes. SCBVF is less sensitive to differential distance between ONUs and can work well in case of small differential distances compared to previously reported void filling schemes. We support our work by extensive simulation study considering bursty traffic with long range dependency. Numerical results show a delay reduction up to 35% compared to non-void filling scheme outperforming its main competitors that can achieve up to 7% delay reduction.

  13. Influence of void density on dislocation mechanisms of void shrinkage in nickel single crystal based on molecular dynamics simulation

    Science.gov (United States)

    Zhang, Yanqiu; Jiang, Shuyong; Zhu, Xiaoming; Zhao, Yanan

    2017-06-01

    Molecular dynamics (MD) simulations were performed to investigate influence of void density on dislocation mechanism of void shrinkage in nickel single crystal. The simulation results show that the higher void density can accelerate the yield of nickel single crystal. During the compression, all the dislocations are emitted toward the other side of the voids, which causes the atoms on the void surface to move into the voids and finally leads to the shrinkage of the voids. There exist six types of dislocations during void shrinkage of nickel single crystal, and the densities of all the six types of dislocations increase with the increase in the void density. The increase of Shockley partial dislocations enhances the slip ability of nickel single crystal, so the void size decreases with the increase in the void density at a constant stain.

  14. 38 CFR 3.207 - Void or annulled marriage.

    Science.gov (United States)

    2010-07-01

    ... 38 Pensions, Bonuses, and Veterans' Relief 1 2010-07-01 2010-07-01 false Void or annulled marriage... Void or annulled marriage. Proof that a marriage was void or has been annulled should consist of: (a... marriage void, together with such other evidence as may be required for a determination. (b) Annulled. A...

  15. Analysis of void formation in thermoplastic composites during resistance welding

    NARCIS (Netherlands)

    Shi, H.; Fernandez Villegas, I.; Bersee, H.E.N.

    2016-01-01

    The process-induced voids during resistance welding of glass fabric-reinforced polyetherimide was investigated. The mechanisms of void formation in adherends, in particular, the residual volatile-induced voids and the fibre de-compaction-induced voids, were analysed. Due to the non-uniform

  16. Seismic Techniques for Subsurface Voids Detection

    Science.gov (United States)

    Gritto, Roland; Korneev, Valeri; Elobaid Elnaiem, Ali; Mohamed, Fathelrahman; Sadooni, Fadhil

    2016-04-01

    A major hazards in Qatar is the presence of karst, which is ubiquitous throughout the country including depressions, sinkholes, and caves. Causes for the development of karst include faulting and fracturing where fluids find pathways through limestone and dissolve the host rock to form caverns. Of particular concern in rapidly growing metropolitan areas that expand in heretofore unexplored regions are the collapse of such caverns. Because Qatar has seen a recent boom in construction, including the planning and development of complete new sub-sections of metropolitan areas, the development areas need to be investigated for the presence of karst to determine their suitability for the planned project. In this paper, we present the results of a study to demonstrate a variety of seismic techniques to detect the presence of a karst analog in form of a vertical water-collection shaft located on the campus of Qatar University, Doha, Qatar. Seismic waves are well suited for karst detection and characterization. Voids represent high-contrast seismic objects that exhibit strong responses due to incident seismic waves. However, the complex geometry of karst, including shape and size, makes their imaging nontrivial. While karst detection can be reduced to the simple problem of detecting an anomaly, karst characterization can be complicated by the 3D nature of the problem of unknown scale, where irregular surfaces can generate diffracted waves of different kind. In our presentation we employ a variety of seismic techniques to demonstrate the detection and characterization of a vertical water collection shaft analyzing the phase, amplitude and spectral information of seismic waves that have been scattered by the object. We used the reduction in seismic wave amplitudes and the delay in phase arrival times in the geometrical shadow of the vertical shaft to independently detect and locate the object in space. Additionally, we use narrow band-pass filtered data combining two

  17. Precision cosmology defeats void models for acceleration

    Science.gov (United States)

    Moss, Adam; Zibin, James P.; Scott, Douglas

    2011-05-01

    The suggestion that we occupy a privileged position near the center of a large, nonlinear, and nearly spherical void has recently attracted much attention as an alternative to dark energy. Putting aside the philosophical problems with this scenario, we perform the most complete and up-to-date comparison with cosmological data. We use supernovae and the full cosmic microwave background spectrum as the basis of our analysis. We also include constraints from radial baryonic acoustic oscillations, the local Hubble rate, age, big bang nucleosynthesis, the Compton y distortion, and for the first time include the local amplitude of matter fluctuations, σ8. These all paint a consistent picture in which voids are in severe tension with the data. In particular, void models predict a very low local Hubble rate, suffer from an “old age problem,” and predict much less local structure than is observed.

  18. Studies in reactive extrusion processing of biodegradable polymeric materials

    Science.gov (United States)

    Balakrishnan, Sunder

    Various reaction chemistries such as Polymerization, Polymer cross-linking and Reactive grafting were investigated in twin-screw extruders. Poly (1,4-dioxan-2-one) (PPDX) was manufactured in melt by the continuous polymerization of 1,4-dioxan-2-one (PDX) monomer in a twin-screw extruder using Aluminum tri-sec butoxide (ATSB) initiator. Good and accurate control over molecular weight was obtained by controlling the ratio of monomer to initiator. A screw configuration consisting of only conveying elements was used for the polymerization. The polymerization reaction was characterized by a monomer-polymer dynamic equilibrium, above the melting temperature of the polymer, limiting the equilibrium conversion to 78-percent. Near complete (˜100-percent) conversion was obtained on co-polymerizing PDX monomer with a few mol-percent (around 8-percent) Caprolactone (CL) monomer in a twin-screw extruder using ATSB initiator. The co-polymers exhibited improved thermal stability with reduction in glass transition temperature. The extruder was modeled as an Axial Dispersed Plug Flow Reactor for the polymerization of CL monomer using Residence Time Distribution (RTD) Analysis. The model provided a good fit to the experimental RTD and conversion data. Aliphatic and aliphatic-aromatic co-polyesters, namely Polycaprolactone (PCL) and Poly butylenes (adipate-co-terephthalate) (Ecoflex) were cross-linked in a twin-screw extruder using radical initiator to form micro-gel reinforced biodegradable polyesters. Cross-linked Ecoflex was further extrusion blended with talc to form blends suitable to be blown into films. A screw configuration consisting of conveying and kneading elements was found to be effective in dispersion of the talc particles (5--10 microns) in the polyester matrix. While the rates of crystallization increased for the talc filled polyester blends, overall crystallinity reduced. Mechanical, tear and puncture properties of films made using the talc filled polyester blends

  19. DIVE in the cosmic web: voids with Delaunay triangulation from discrete matter tracer distributions

    Science.gov (United States)

    Zhao, Cheng; Tao, Charling; Liang, Yu; Kitaura, Francisco-Shu; Chuang, Chia-Hsun

    2016-07-01

    We present a novel parameter-free cosmological void finder (DIVE, Delaunay TrIangulation Void findEr) based on Delaunay Triangulation (DT), which efficiently computes the empty spheres constrained by a discrete set of tracers. We define the spheres as DT voids, and describe their properties, including a universal density profile together with an intrinsic scatter. We apply this technique on 100 halo catalogues with volumes of 2.5 h-1Gpc side each, with a bias and number density similar to the Baryon Oscillation Spectroscopic Survey CMASS luminous red galaxies, performed with the PATCHY code. Our results show that there are two main species of DT voids, which can be characterized by the radius: they have different responses to halo redshift space distortions, to number density of tracers, and reside in different dark matter environments. Based on dynamical arguments using the tidal field tensor, we demonstrate that large DT voids are hosted in expanding regions, whereas the haloes used to construct them reside in collapsing ones. Our approach is therefore able to efficiently determine the troughs of the density field from galaxy surveys, and can be used to study their clustering. We further study the power spectra of DT voids, and find that the bias of the two populations are different, demonstrating that the small DT voids are essentially tracers of groups of haloes.

  20. A study of coal-solid waste blend reactivity

    Directory of Open Access Journals (Sweden)

    Nayibe Guerrero

    2008-05-01

    Full Text Available The Flynn-Wall-Ozawa method was used for analysing coal-solid waste blend reactivity in an oxidising atmosphere. The presence of biomass strongly affected coal combustion kinetics when the blend contained more than 30% of it. Activation energy values (evaluated by different blends were 28.7495 kJ/mol for 0% biomass, 31.3915 kJ/mol for 30% biomass, 39.0365 kJ/mol for 50% biomass, 102.431 kJ/mol for 70% biomass and 107.8075 kJ/mol for 100% biomass; these values were close to those reported in the literature. First-order kinetics correlated the data ve-ry well for the 100% coal sample and the blend having 30% biomass and 70% coal. Eighth-order kinetics were more suitable for correlating the experimental data for the 70% biomass-30% coal blend and the 100% biomass sample. Combustion was done without previous pyrolysis of the blends; however segregation of phenomena could be appre-ciated. This seems to indicate that combustion and devolatilisation are independent processes which should be taken into account when building equipment using these kinds of blend.

  1. Calcium polyphosphate particulates for bone void filler applications.

    Science.gov (United States)

    Pilliar, Robert M; Kandel, Rita A; Grynpas, Marc D; Theodoropoulos, John; Hu, Youxin; Allo, Bedilu; Changoor, Adele

    2017-05-01

    This study investigates the characteristics of porous calcium polyphosphate particulates (CPPp) formed using two different processing treatments as bone void fillers in non- or minimally load-bearing sites. The two calcium polyphosphate particulate variants (grades) were formed using different annealing conditions during particulate preparation to yield either more slowly degrading calcium polyphosphate particulates (SD-CPPp) or faster degrading particulates (FD-CPPp) as suggested by a previous degradation study conducted in vitro (Hu et al., Submitted for publication 2016). The two CPPp grades were compared as bone void fillers in vivo by implanting particulates in defects created in rabbit femoral condyle sites (critical size defects). The SD-CPPp and FD-CPPp were implanted for 4- and 16-week periods. The in vivo study indicated a significant difference in amount of new bone formed in the prepared sites with SD-CPPp resulting in more new bone formation compared with FD-CPPp. The lower bone formation characteristic of the FD-CPPp was attributed to its faster degradation rate and resulting higher local concentration of released polyphosphate degradation products. The study results indicate the importance of processing conditions on preparing calcium polyphosphate particulates for potential use as bone void fillers in nonload-bearing sites. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 874-884, 2017. © 2016 Wiley Periodicals, Inc.

  2. submitter Thermal stability of interface voids in Cu grain boundaries with molecular dynamic simulations

    CERN Document Server

    Xydou, A; Aicheler, M; Djurabekova, F

    2016-01-01

    By means of molecular dynamic simulations, the stability of cylindrical voids is examined with respect to the diffusion bonding procedure. To do this, the effect of grain boundaries between the grains of different crystallographic orientations on the void closing time was studied at high temperatures from 0.7 up to 0.94 of the bulk melting temperature $(T_m)$. The diameter of the voids varied from 3.5 to 6.5 nm. A thermal instability occurring at high temperatures at the surface of the void placed in a grain boundary triggered the eventual closure of the void at all examined temperatures. The closing time has an exponential dependence on the examined temperature values. A model based on the defect diffusion theory is developed to predict the closing time for voids of macroscopic size. The diffusion coefficient within the grain boundaries is found to be overall higher than the diffusion coefficient in the region around the void surface. The activation energy for the diffusion in the grain boundary is calculate...

  3. A variational constitutive model for the distribution and interactions of multi-sized voids

    KAUST Repository

    Liu, Jinxing

    2013-07-29

    The evolution of defects or voids, generally recognized as the basic failure mechanism in most metals and alloys, has been intensively studied. Most investigations have been limited to spatially periodic cases with non-random distributions of the radii of the voids. In this study, we use a new form of the incompressibility of the matrix to propose the formula for the volumetric plastic energy of a void inside a porous medium. As a consequence, we are able to account for the weakening effect of the surrounding voids and to propose a general model for the distribution and interactions of multi-sized voids. We found that the single parameter in classical Gurson-type models, namely void volume fraction is not sufficient for the model. The relative growth rates of voids of different sizes, which can in principle be obtained through physical or numerical experiments, are required. To demonstrate the feasibility of the model, we analyze two cases. The first case represents exactly the same assumption hidden in the classical Gurson\\'s model, while the second embodies the competitive mechanism due to void size differences despite in a much simpler manner than the general case. Coalescence is implemented by allowing an accelerated void growth after an empirical critical porosity in a way that is the same as the Gurson-Tvergaard-Needleman model. The constitutive model presented here is validated through good agreements with experimental data. Its capacity for reproducing realistic failure patterns is shown by simulating a tensile test on a notched round bar. © 2013 The Author(s).

  4. Density functional theory study on the formation of reactive benzoquinone imines by hydrogen abstraction

    DEFF Research Database (Denmark)

    Leth, Rasmus; Rydberg, Patrik; Jørgensen, Flemming Steen

    2015-01-01

    Many drug compounds are oxidized by cytochrome P450 (CYP) enzymes to form reactive metabolites. This study presents density functional theory calculations of the CYP-mediated metabolism of acetaminophen and a series of related compounds that can form reactive metabolites by hydrogen abstraction. ...... as an in silico method in the design of new compounds with improved metabolic stability.......Many drug compounds are oxidized by cytochrome P450 (CYP) enzymes to form reactive metabolites. This study presents density functional theory calculations of the CYP-mediated metabolism of acetaminophen and a series of related compounds that can form reactive metabolites by hydrogen abstraction...... the porphyrin model to determine the activation energies. We have used this correlation on monosubstituted phenols to rationalize the effect of the various substituents in the drug compounds. In addition to facilitating a chemical interpretation, the approach is sufficiently fast and reliable to be used...

  5. Effects of percutaneous posterior tibial nerve stimulation on voiding dysfunctions in cerebral palsy: A case report

    Directory of Open Access Journals (Sweden)

    Farshideh Alishahi

    2017-01-01

    Full Text Available The present study, conducted on three children with cerebral palsy who had voiding dysfunction. After collecting demographic information, symptoms of voiding dysfunctions were recorded. Then; we did an ultrasonographic evaluation of the bladder to measure residual urine volume. Physiotherapy treatment through percutaneous electrical stimulation of the posterior tibial nerve was performed in 12 sessions. Bladder ultrasonography was repeated after treatment. Abnormal residual urine volume became normal in patients with urinary retention. Percutaneous posterior tibial nerve stimulation reduces symptoms of voiding dysfunctions in children with cerebral palsy

  6. Effect of Void Size on the Detonation Pressure of Emulsion Explosives

    Science.gov (United States)

    Hirosaki, Yoshikazu; Murata, Kenji; Kato, Yukio; Itoh, Shigeru

    2002-07-01

    To study the effect of void size, detonation pressure as well as detonation velocity was measured using PVDF pressure gauge for the emulsion explosives sensitized with plastic balloons of five different size ranging from 0.05mm to 2.42mm. The experimental results were compared with the detonation pressure and velocity calculated using KHT code. The experimental results showed that the detonation pressure and velocity were strongly affected by void size, and that the fraction of ammonium nitrate reacted in the reaction zone was strongly dependent on void size.

  7. Blunted cardiac reactivity to psychological stress associated with higher trait anxiety: a study in peacekeepers

    OpenAIRE

    de Souza, Gabriela Guerra Leal; Mendon?a-de-Souza, Ana Carolina Ferraz; Duarte, Ant?nio Fernando Ara?jo; Fischer, Nastassja Lopes; Souza, Wanderson Fernandes de; Silva Freire Coutinho, Evandro; Figueira, Ivan; Volchan,Eliane

    2015-01-01

    Background Both exaggerated and diminished reactivity to stress can be maladaptive. Previous studies have shown that performing increasingly difficult tasks leads first to increased reactivity and then to a blunted response when success is impossible. Our aim was to investigate the influence of trait anxiety on cardiac and cortisol response to and recovery from a standardized psychosocial stress task (Trier Social Stress Task) in a homogeneous sample of healthy peacekeepers. We hypothesized t...

  8. URODYNAMIC EVALUATION OF VOIDING FUNCTION IN ...

    African Journals Online (AJOL)

    Objective The evaluation of voiding function in females with lower urinary tract symptoms (LUTS) with a special emphasis on the evaluation of storage function and the state of continence. Patients and Methods 176 patients were investigated for urinary incontinence-related problems at the Unit for Neuro-Urology and ...

  9. Voiding dysfunction in women following cesarean delivery

    Directory of Open Access Journals (Sweden)

    Ching-Chung Liang

    2015-12-01

    Conclusion: Our results showed that emergency cesarean delivery, prolonged operation time and postoperative analgesia are the main contributing factors of PVD after cesarean delivery. If urinary retention can be detected in time, transient PVD is not detrimental to urinary function and does not subsequently lead to voiding problems.

  10. The Metallicity of Void Dwarf Galaxies

    NARCIS (Netherlands)

    Kreckel, K.; Croxall, K.; Groves, B.; van de Weygaert, R.; Pogge, R. W.

    The current ΛCDM cosmological model predicts that galaxy evolution proceeds more slowly in lower density environments, suggesting that voids are a prime location to search for relatively pristine galaxies that are representative of the building blocks of early massive galaxies. To test the

  11. "Dark energy" in the Local Void

    Science.gov (United States)

    Villata, M.

    2012-05-01

    The unexpected discovery of the accelerated cosmic expansion in 1998 has filled the Universe with the embarrassing presence of an unidentified "dark energy", or cosmological constant, devoid of any physical meaning. While this standard cosmology seems to work well at the global level, improved knowledge of the kinematics and other properties of our extragalactic neighborhood indicates the need for a better theory. We investigate whether the recently suggested repulsive-gravity scenario can account for some of the features that are unexplained by the standard model. Through simple dynamical considerations, we find that the Local Void could host an amount of antimatter (˜5×1015 M ⊙) roughly equivalent to the mass of a typical supercluster, thus restoring the matter-antimatter symmetry. The antigravity field produced by this "dark repulsor" can explain the anomalous motion of the Local Sheet away from the Local Void, as well as several other properties of nearby galaxies that seem to require void evacuation and structure formation much faster than expected from the standard model. At the global cosmological level, gravitational repulsion from antimatter hidden in voids can provide more than enough potential energy to drive both the cosmic expansion and its acceleration, with no need for an initial "explosion" and dark energy. Moreover, the discrete distribution of these dark repulsors, in contrast to the uniformly permeating dark energy, can also explain dark flows and other recently observed excessive inhomogeneities and anisotropies of the Universe.

  12. Coastal Meringues: Are Salt Marshes Inflated with Excess Void Spaces?

    Science.gov (United States)

    Gunnell, J. R.

    2016-02-01

    Failure to stay above sea level is among many ways that salt marshes may be destroyed. This race against the sea is carried out by vertical accretion. Accretion is partly the accumulation of material mediated by vegetative and sedimentary feedbacks. Prognoses for salt marshes based on studies of these variables have proven useful, but they may also be failing to read between the lines. After all, the majority of a salt marsh's volume is typically comprised of void spaces, which seem to be under-examined in our current predictions of salt marsh survival. Salt marshes may be inflated with excess void spaces, occupying greater volumes than sedimentary predictions would otherwise assume. To test this hypothesis, benthic porosity measurements were drawn from a USGS database of thousands of seabed samples along the U.S. Atlantic and Gulf coasts. Seabed porosities were used to geostatistically interpolate expected porosities at selected salt marsh sites. Measurements of known salt marsh porosities were drawn from several case studies in the literature. These salt marsh porosity measurements were georeferenced so they could be compared to the expected seabed porosity determined by spatial interpolation. Initial results show that these salt marshes tend to be more porous than the benthic sediments surrounding them. This excess porosity can be an important contributor to marsh volume (i.e. elevation), and ultimately to marsh survival. Furthermore, it raises several questions about the source of this void space and the mechanism of its retention. Salt marsh volume appears to be greater than we would expect based on the sum of its parts. Therefore, predictions of salt marsh accretion may systematically underestimate void volumes and be overly pessimistic about marsh response to relative sea level rise.

  13. Solid phase studies and geochemical modelling of low-cost permeable reactive barriers.

    Science.gov (United States)

    Bartzas, Georgios; Komnitsas, Kostas

    2010-11-15

    A continuous column experiment was carried out under dynamic flow conditions in order to study the efficiency of low-cost permeable reactive barriers (PRBs) to remove several inorganic contaminants from acidic solutions. A 50:50 w/w waste iron/sand mixture was used as candidate reactive media in order to activate precipitation and promote sorption and reduction-oxidation mechanisms. Solid phase studies of the exhausted reactive products after column shutdown, using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), confirmed that the principal Fe corrosion products identified in the reactive zone are amorphous iron (hydr)oxides (maghemite/magnetite and goethite), intermediate products (sulfate green rust), and amorphous metal sulfides such as amFeS and/or mackinawite. Geochemical modelling of the metal removal processes, including interactions between reactive media, heavy metal ions and sulfates, and interpretation of the ionic profiles was also carried out by using the speciation/mass transfer computer code PHREEQC-2 and the WATEQ4F database. Mineralogical characterization studies as well as geochemical modelling calculations also indicate that the effect of sulfate and silica sand on the efficiency of the reactive zone should be considered carefully during design and operation of low-cost field PRBs. Copyright © 2010 Elsevier B.V. All rights reserved.

  14. The role of bone void fillers in medial opening wedge high tibial osteotomy: a systematic review.

    Science.gov (United States)

    Slevin, Omer; Ayeni, Olufemi R; Hinterwimmer, Stefan; Tischer, Thomas; Feucht, Matthias J; Hirschmann, Michael T

    2016-11-01

    A variety of bone void filling materials and methods are available in opening medial wedge HTO (OWHTO). The pertinent question revolves around if and when bone void fillers are needed. The primary purpose of this study was to systematically review outcomes and complications after OWHTO with and without the use of bone void fillers. The EMBASE, PubMed\\MEDLINE, Cochrane Library and Google Scholar databases were searched to identify articles that reported OWHTO results using different bone void fillers until March 2016. Only articles reporting the exact bone void filler type, the opening gap size and the fixation method were included. The extracted data included the study design, demographic data, the radiological and clinical results and complication rates. Outcomes were analysed with regard to bone void filler type, and comparison was made between the groups (allograft, autograft, synthetic bone void filler and OWHTO without bone void filling). Twenty-two articles reporting the results of 1421 OWHTO met the inclusion criteria. In total, 647 osteotomies were completed with allogeneic graft as bone void filler, 367 with synthetic materials, 199 with autograft and 208 without any bone void filling material. The maximum opening gap size was similar in all groups with mean of 9.8 mm (range 4-17.5 mm). Locking plate fixation was used in 90 % of the osteotomies that were completed without bone void filler, while all allograft cases and more then 90 % of the autograft cases were done with non-locking systems. The highest rates of non-union (1.1 %) were seen in the synthetic group, compared to 0.5 % in the all the other groups. This systematic review showed no definitive advantages for OWHTO with any bone void filler in terms of union rates and loss of correction. Moreover, the use of autografts or allografts showed more favourable outcomes than synthetic bone substitutes. OWHTO with gaps smaller then 10 mm and rigid fixation might be successfully managed without

  15. An improved void-resistance model for abandoned coal mine gas reservoirs

    OpenAIRE

    Shi, JQ; Rubio, RM; Durucan, S.

    2016-01-01

    Previous studies have shown that the gas pressure behaviour of some abandoned coal mines may be described with the aid of a simple conceptual model, the so called void-resistance model. In this study, an improved void-resistance model has been developed and validated using previously collected data. Two model parameters, i.e. an apparent source/sink pressure and a time constant, which control the gas pressure behaviour during recharge and under certain gas production conditions, are defined. ...

  16. Quantitative void fraction detection with an eddy current flowmeter for generation IV Sodium cooled Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, M. [Institut de Mecanique des Fluides de Toulouse, 2 Allee du Professeur Camille Soula, 31400 Toulouse, (France); French Atomic Energy and Alternative Energies Commission (CEA), DEN, Laboratory of Instrumentation and technological Test, Cadarache, 13108 Saint Paul lez Durance, (France); Tordjeman, Ph.; Bergez, W. [Institut de Mecanique des Fluides de Toulouse, 2 Allee du Professeur Camille Soula, 31400 Toulouse, (France); Cavaro, M.; Paumel, K.; Jeannot, J. P. [French Atomic Energy and Alternative Energies Commission (CEA), DEN, Laboratory of Instrumentation and technological Test, Cadarache, 13108 Saint Paul lez Durance, (France)

    2015-07-01

    This study was carried out to understand the response of an eddy current type flowmeter in two phase liquid-metal flow. We use the technique of ellipse fit and correlate the fluctuations in the angle of inclination of this ellipse with the void fraction. The effects of physical parameters such as coil excitation frequency and flow velocity have been studied. The results show the possibility of using an eddy current flowmeter as a gas detector for large void fractions. (authors)

  17. Quantitative void fraction measurement with an eddy current flowmeter for generation IV Sodium cooled Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, M. [Institut de Mecanique des Fluides de Toulouse, 2 Allee du Professeur Camille Soula, 31400 Toulouse (France); CEA, DEN, Nuclear Technology Department, F-13108 Saint-Paul-lez-Durance (France); Tordjeman, Ph.; Bergez, W. [Institut de Mecanique des Fluides de Toulouse, 2 Allee du Professeur Camille Soula, 31400 Toulouse (France); Cavaro, M.; Paumel, K.; Jeannot, J.P. [CEA, DEN, Nuclear Technology Department, F-13108 Saint-Paul-lez-Durance (France)

    2015-07-01

    This study was carried out to understand the response of an eddy current type flowmeter in two phase liquid-metal flow. We use the technique of ellipse fit and correlate the fluctuations in the angle of inclination of this ellipse with the void fraction. The effects of physical parameters such as coil excitation frequency and flow velocity have been studied. The results show the possibility of using an eddy current flowmeter as a gas detector for large void fractions. (authors)

  18. Effect of endocrine treatment on voiding and prostate size in men with prostate cancer

    DEFF Research Database (Denmark)

    Klarskov, Louise L; Klarskov, Peter; Mommsen, Søren

    2012-01-01

    The aim of this study was to assess and quantify changes in voiding parameters and prostate size in men with prostate cancer from before the start of endocrine treatment and during long-term follow-up.......The aim of this study was to assess and quantify changes in voiding parameters and prostate size in men with prostate cancer from before the start of endocrine treatment and during long-term follow-up....

  19. Enthalpy and void distributions in subchannels of PHWR fuel bundles

    Energy Technology Data Exchange (ETDEWEB)

    Park, J. W.; Choi, H.; Rhee, B. W. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1998-12-31

    Two different types of the CANDU fuel bundles have been modeled for the ASSERT-IV code subchannel analysis. From calculated values of mixture enthalpy and void fraction distribution in the fuel bundles, it is found that net buoyancy effect is pronounced in the central region of the DUPIC fuel bundle when compared with the standard CANDU fuel bundle. It is also found that the central region of the DUPIC fuel bundle can be cooled more efficiently than that of the standard fuel bundle. From the calculated mixture enthalpy distribution at the exit of the fuel channel, it is found that the mixture enthalpy and void fraction can be highest in the peripheral region of the DUPIC fuel bundle. On the other hand, the enthalpy and the void fraction were found to be highest in the central region of the standard CANDU fuel bundle at the exit of the fuel channel. This study shows that the subchannel analysis is very useful in assessing thermal behavior of the fuel bundle that could be used in CANDU reactors. 10 refs., 4 figs., 2 tabs. (Author)

  20. Cognitive Reactivity, Implicit Associations, and the Incidence of Depression: A Two-Year Prospective Study

    Science.gov (United States)

    Kruijt, Anne-Wil; Antypa, Niki; Booij, Linda; de Jong, Peter J.; Glashouwer, Klaske; Penninx, Brenda W. J. H.; Van der Does, Willem

    2013-01-01

    Background Cognitive reactivity to sad mood is a vulnerability marker of depression. Implicit self-depressed associations are related to depression status and reduced remission probability. It is unknown whether these cognitive vulnerabilities precede the first onset of depression. Aim To test the predictive value of cognitive reactivity and implicit self-depressed associations for the incidence of depressive disorders. Methods Prospective cohort study of 834 never-depressed individuals, followed over a two-year period. The predictive value of cognitive reactivity and implicit self-depressed associations for the onset of depressive disorders was assessed using binomial logistic regression. The multivariate model corrected for baseline levels of subclinical depressive symptoms, neuroticism, for the presence of a history of anxiety disorders, for family history of depressive or anxiety disorders, and for the incidence of negative life events. Results As single predictors, both cognitive reactivity and implicit self-depressed associations were significantly associated with depression incidence. In the multivariate model, cognitive reactivity was significantly associated with depression incidence, together with baseline depressive symptoms and the number of negative life events, whereas implicit self-depressed associations were not. Conclusion Cognitive reactivity to sad mood is associated with the incidence of depressive disorders, also when various other depression-related variables are controlled for. Implicit self-depressed associations predicted depression incidence in a bivariate test, but not when controlling for other predictors. PMID:23922962

  1. Cognitive reactivity, implicit associations, and the incidence of depression: a two-year prospective study.

    Directory of Open Access Journals (Sweden)

    Anne-Wil Kruijt

    Full Text Available BACKGROUND: Cognitive reactivity to sad mood is a vulnerability marker of depression. Implicit self-depressed associations are related to depression status and reduced remission probability. It is unknown whether these cognitive vulnerabilities precede the first onset of depression. AIM: To test the predictive value of cognitive reactivity and implicit self-depressed associations for the incidence of depressive disorders. METHODS: Prospective cohort study of 834 never-depressed individuals, followed over a two-year period. The predictive value of cognitive reactivity and implicit self-depressed associations for the onset of depressive disorders was assessed using binomial logistic regression. The multivariate model corrected for baseline levels of subclinical depressive symptoms, neuroticism, for the presence of a history of anxiety disorders, for family history of depressive or anxiety disorders, and for the incidence of negative life events. RESULTS: As single predictors, both cognitive reactivity and implicit self-depressed associations were significantly associated with depression incidence. In the multivariate model, cognitive reactivity was significantly associated with depression incidence, together with baseline depressive symptoms and the number of negative life events, whereas implicit self-depressed associations were not. CONCLUSION: Cognitive reactivity to sad mood is associated with the incidence of depressive disorders, also when various other depression-related variables are controlled for. Implicit self-depressed associations predicted depression incidence in a bivariate test, but not when controlling for other predictors.

  2. Cognitive reactivity, implicit associations, and the incidence of depression: a two-year prospective study.

    Science.gov (United States)

    Kruijt, Anne-Wil; Antypa, Niki; Booij, Linda; de Jong, Peter J; Glashouwer, Klaske; Penninx, Brenda W J H; Van der Does, Willem

    2013-01-01

    Cognitive reactivity to sad mood is a vulnerability marker of depression. Implicit self-depressed associations are related to depression status and reduced remission probability. It is unknown whether these cognitive vulnerabilities precede the first onset of depression. To test the predictive value of cognitive reactivity and implicit self-depressed associations for the incidence of depressive disorders. Prospective cohort study of 834 never-depressed individuals, followed over a two-year period. The predictive value of cognitive reactivity and implicit self-depressed associations for the onset of depressive disorders was assessed using binomial logistic regression. The multivariate model corrected for baseline levels of subclinical depressive symptoms, neuroticism, for the presence of a history of anxiety disorders, for family history of depressive or anxiety disorders, and for the incidence of negative life events. As single predictors, both cognitive reactivity and implicit self-depressed associations were significantly associated with depression incidence. In the multivariate model, cognitive reactivity was significantly associated with depression incidence, together with baseline depressive symptoms and the number of negative life events, whereas implicit self-depressed associations were not. Cognitive reactivity to sad mood is associated with the incidence of depressive disorders, also when various other depression-related variables are controlled for. Implicit self-depressed associations predicted depression incidence in a bivariate test, but not when controlling for other predictors.

  3. Three-Dimensional Computed Tomography as a Method for Finding Die Attach Voids in Diodes

    Science.gov (United States)

    Brahm, E. N.; Rolin, T. D.

    2010-01-01

    NASA analyzes electrical, electronic, and electromechanical (EEE) parts used in space vehicles to understand failure modes of these components. The diode is an EEE part critical to NASA missions that can fail due to excessive voiding in the die attach. Metallography, one established method for studying the die attach, is a time-intensive, destructive, and equivocal process whereby mechanical grinding of the diodes is performed to reveal voiding in the die attach. Problems such as die attach pull-out tend to complicate results and can lead to erroneous conclusions. The objective of this study is to determine if three-dimensional computed tomography (3DCT), a nondestructive technique, is a viable alternative to metallography for detecting die attach voiding. The die attach voiding in two- dimensional planes created from 3DCT scans was compared to several physical cross sections of the same diode to determine if the 3DCT scan accurately recreates die attach volumetric variability

  4. Effects of testosterone replacement therapy withdrawal and re-treatment in hypogonadal elderly men upon obesity, voiding function and prostate safety parameters.

    Science.gov (United States)

    Yassin, Aksam; Nettleship, Joanne E; Talib, Raidh A; Almehmadi, Yousef; Doros, Gheorge

    2016-01-01

    Whether testosterone replacement therapy (TRT) is a lifelong treatment for men with hypogonadism remains unknown. We investigated long-term TRT and TRT withdrawal on obesity and prostate-related parameters. Two hundred and sixty-two hypogonadal patients (mean age 59.5) received testosterone undecanoate in 12-week intervals for a maximum of 11 years. One hundred and forty-seven men had TRT interrupted for a mean of 16.9 months and resumed thereafter (Group A). The remaining 115 patients were treated continuously (Group B). Prostate volume, prostate-specific antigen (PSA), residual voiding volume, bladder wall thickness, C-reactive protein (CRP), aging male symptoms (AMS), International Index of erectile function - erectile function (IIEF-EF) and International Prostate Symptoms Scores (IPSS) were measured over the study period with anthropometric parameters of obesity, including weight, body mass index (BMI) and waist circumference. Prior to interruption, TRT resulted in improvements in residual voiding volume, bladder wall thickness, CRP, AMS, IIEF-EF, IPSS and obesity parameters while PSA and prostate volume increased. TRT interruption reduced total testosterone to hypogonadal levels in Group A and resulted in worsening of obesity parameters, AMS, IPSS, residual voiding volume and bladder wall thickness, IIEF-EF and PSA while CRP and prostate volume were unchanged until treatment resumed whereby these effects were reversed. TRT interruption results in worsening of symptoms. Hypogonadism may require lifelong TRT.

  5. Risk management of low air void asphalt concrete mixtures.

    Science.gov (United States)

    2013-07-01

    Various forms of asphalt pavement distress, such as rutting, shoving and bleeding, can be attributed, in many cases, to low air voids in : the mixtures during production and placement. The occurrence of low air void contents during plant production m...

  6. Effects of percutaneous posterior tibial nerve stimulation on voiding dysfunctions in cerebral palsy: A case report

    OpenAIRE

    Farshideh Alishahi; Reza Farjad; Farideh Dehghan Manshadi

    2016-01-01

    The present study, conducted on three children with cerebral palsy who had voiding dysfunction. After collecting demographic information, symptoms of voiding dysfunctions were recorded. Then; we did an ultrasonographic evaluation of the bladder to measure residual urine volume. Physiotherapy treatment through percutaneous electrical stimulation of the posterior tibial nerve was performed in 12 sessions. Bladder ultrasonography was repeated after treatment. Abnormal residual urine volume becam...

  7. Towards spatial kinetics in a low void effect sodium fast reactor: core analysis and validation of the TFM neutronic approach

    Directory of Open Access Journals (Sweden)

    Laureau Axel

    2017-01-01

    Full Text Available The studies presented in this paper are performed in the general framework of transient coupled calculations with accurate neutron kinetics models able to characterize spatial decoupling in the core. An innovative fission matrix interpolation model has been developed with a correlated sampling technique associated to the Transient Fission Matrix (TFM approach. This paper presents a validation of this Monte Carlo based kinetic approach on sodium fast reactors. An application case representative of an assembly of the low void effect sodium fast reactor ASTRID is used to study the physics of this kind of system and to illustrate the capabilities provided by this approach. To validate the interpolation model developed, different comparisons have been performed with direct Monte Carlo and ERANOS deterministic S N calculations on spatial kinetics parameters (flux redistribution, reactivity estimation, etc. together with point kinetics feedback estimations.

  8. Influence of application techniques on contact formation and voids in anterior resin composite restorations.

    Science.gov (United States)

    Kwon, S R; Oyoyo, U; Li, Y

    2014-01-01

    This study evaluated the influence of three different application techniques on contact formation and voids in anterior resin composite restorations. Artificial ivorine teeth were randomly assigned to three experimental groups, with 20 specimens in each group. One operator performed all restorations using the Teflon tape, pull-through, or bioclear matrix technique. The treatment time required for each restoration was recorded. An examiner blinded to the treatment group performed the visual evaluation of six criteria, including proper contact formation. The restored teeth were cut to yield a total of 180 sections for microscopic evaluation. The Kruskal-Wallis procedure was performed to evaluate the significance of treatment time, number of voids, percent porosity area, and void diameter. There were significant differences in treatment time among the three groups (pdiastema closure (p0.05). However, the mean void diameter was greater with the bioclear matrix technique compared to the other two techniques (p<0.05).

  9. Pozzolanic Reactivity of Silica Fume and Ground Rice Husk Ash as Reactive Silica in a Cementitious System: A Comparative Study.

    Science.gov (United States)

    Xu, Weiting; Lo, Tommy Yiu; Wang, Weilun; Ouyang, Dong; Wang, Penggang; Xing, Feng

    2016-03-01

    This study comparably assessed the pozzolanic effect of silica fume (SF) and ground rice husk ash (RHA) as supplementary cementing materials on the properties of blended cement pastes and concretes. A commonly commercial silica fume (SF) and locally-produced rice husk ash (RHA) samples with two finenesses (one with larger size than cement and the other with smaller size than cement) were used in this study. Material properties of SF and RHA were experimentally characterized. Hydration and mechanical properties of cement pastes incorporating SF and RHA were determined by thermogravimetric analysis (TGA) and compressive strength tests, respectively. Properties of concretes regarding workability, mechanical property, durability, and microstructure were evaluated. Results showed that, although the finely ground RHA used in this study possessed lower SiO₂ content and higher particle size compared to SF, it exhibited comparable pozzolanic reactivity with SF due to the nano-scale pores on its each single particle, leading to a higher specific surface area. The optimal replacement levels of SF and RHA were 10% by weight of cement in pastes and concretes. Although addition of SF and RHA led to a significant reduction in slump for the fresh mixtures, inclusion of up to 30% of SF or 15% of ground RHA did not adversely affect the strength of concretes. At the same mix, incorporation of finely-ground RHA in cement composites provided comparable mechanical properties, hydration degree, and durability with SF blended cement composites, owing to the porous structure and high specific surface area of RHA particles. Microstructure morphology analysis of concretes explored by scanning electron microscopy (SEM) further validated the strength and the durability test results.

  10. Pozzolanic Reactivity of Silica Fume and Ground Rice Husk Ash as Reactive Silica in a Cementitious System: A Comparative Study

    Directory of Open Access Journals (Sweden)

    Weiting Xu

    2016-03-01

    Full Text Available This study comparably assessed the pozzolanic effect of silica fume (SF and ground rice husk ash (RHA as supplementary cementing materials on the properties of blended cement pastes and concretes. A commonly commercial silica fume (SF and locally-produced rice husk ash (RHA samples with two finenesses (one with larger size than cement and the other with smaller size than cement were used in this study. Material properties of SF and RHA were experimentally characterized. Hydration and mechanical properties of cement pastes incorporating SF and RHA were determined by thermogravimetric analysis (TGA and compressive strength tests, respectively. Properties of concretes regarding workability, mechanical property, durability, and microstructure were evaluated. Results showed that, although the finely ground RHA used in this study possessed lower SiO2 content and higher particle size compared to SF, it exhibited comparable pozzolanic reactivity with SF due to the nano-scale pores on its each single particle, leading to a higher specific surface area. The optimal replacement levels of SF and RHA were 10% by weight of cement in pastes and concretes. Although addition of SF and RHA led to a significant reduction in slump for the fresh mixtures, inclusion of up to 30% of SF or 15% of ground RHA did not adversely affect the strength of concretes. At the same mix, incorporation of finely-ground RHA in cement composites provided comparable mechanical properties, hydration degree, and durability with SF blended cement composites, owing to the porous structure and high specific surface area of RHA particles. Microstructure morphology analysis of concretes explored by scanning electron microscopy (SEM further validated the strength and the durability test results.

  11. Plasticity size effects in voided crystals

    DEFF Research Database (Denmark)

    Hussein, M.I.; Borg, Ulrik; Niordson, Christian Frithiof

    2008-01-01

    The shear and equi-biaxial straining responses of periodic voided single crystals are analysed using discrete dislocation plasticity and a continuum strain gradient crystal plasticity theory. In the discrete dislocation formulation, the dislocations are all of edge character and are modelled...... between predictions of the two formulations for all crystal types and void volume fractions considered when the material length scale in the non-local plasticity model is chosen to be 0.325 mu m (about 10 times the slip plane spacing in the discrete dislocation models)....... as line singularities in an elastic material. The lattice resistance to dislocation motion, dislocation nucleation, dislocation interaction with obstacles and annihilation are incorporated through a set of constitutive rules. Over the range of length scales investigated, both the discrete dislocation...

  12. Plasticity size effects in voided crystals

    DEFF Research Database (Denmark)

    Hussein, M. I.; Borg, Ulrik; Niordson, Christian Frithiof

    The shear and equi-biaxial straining responses of periodic voided single crystals are analysed using discrete dislocation plasticity and a continuum strain gradient crystal plasticity theory. In the discrete dislocation formulation the dislocations are all of edge character and are modelled as line...... predictions of the two formulations for all crystal types and void volume fractions considered when the material length scale in the non-local plasticity model chosen to be $0.325\\mu m$ (around ten times the slip plane spacing in the discrete dislocation models)....... singularities in an elastic material. The lattice resistance to dislocation motion, dislocation nucleation, dislocation interaction with obstacles and annihilation are incorporated through a set of constitutive rules. Over the range of length scales investigated, both the discrete dislocation and strain...

  13. Influence of ageing, inclusions and voids on ductile fracture ...

    Indian Academy of Sciences (India)

    Unknown

    increases (Cabot and Burlion 1996). Voids that initiate at particular inclusions can grow to a uniform size consi- derably in excess of the average particle spacing without the interference of adjacent particles, or the initiation of additional voids at these adjacent particles. 3.3 Void coalescence and the effect of small inclusions.

  14. The Cosmically Depressed : Life, Sociology and Identity of Voids

    NARCIS (Netherlands)

    van de Weygaert, R.; Platen, E.; Tigrak, E.; Hidding, J.; van der Hulst, J. M.; Aragon-Calvo, M. A.; Stanonik, K.; van Gorkom, J. H.; VerdesMontenegro, L; DelOlmo, A; Sulentic, J

    2010-01-01

    In this contribution we review and discuss several aspects of Cosmic Voids, as a background for our void galaxy project (accompanying paper by Stanonik et al.). Voids are a major component of the large scale distribution of matter and galaxies in the Universe. Following a sketch of the general

  15. Effect of void cluster on ductile failure evolution

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2016-01-01

    , are the same for the clusters and the single void. In the comparison it is essential that local void coalescence inside the clusters is accounted for, since this allows for considering the rate of growth of the single larger void that results from coalescence in the cluster. To obtain a parametric...

  16. Quantitative analysis of C-reactive protein in potentially malignant disorders: A pilot study

    Directory of Open Access Journals (Sweden)

    Srilalitha Kaja

    2015-01-01

    Full Text Available Background: Recent advances in understanding complex tumor interactions have led to the discovery of an association between inflammation and cancer. An abundance of pro - inflammatory cytokines in a tumor micro-environment can lead to angiogenesis, thus favoring neoplastic growth. Serum C reactive protein is a sensitive marker of inflammation and may have significant prognostic value as early biomarker for cancer diagnostics. Aims and Objectives: This was a pilot study done to assess the serum C reactive protein levels in potentially malignant disorders (PMDS and to evaluate their role as prognostic marker. Materials and Methods: The study sample consisted of 20 cases of oral potentially malignant disorders (10 each of Leukoplakia, Oral Sub mucous fibrosis confirmed by histopathological examination and 10 controls. All the samples were subjected to C - reactive protein analysis by immunoturbidometery. Results were subjected to Statistical analysis. Statistical analysis: Data was entered in data base management of the software SPSS version 20.0. Comparison of three groups with respect to C reactive protein levels was done by one way ANOVA. Pair wise comparison of three groups was done by Turkeys multiple post hoc procedure. Results: Mean C reactive protein levels in leukoplakia was 0.33±0.17, in oral submucous fibrosis was 0.58±0.83 where as in controls it was 0.26±0.05. In potentially malignant disorders, C reactive protein was slightly elevated when compared with the controls. Conclusion: Our findings demonstrate that serum C reactive protein concentration is associated with subsequent development of oral cancer and could serve as a potential prognostic biomarker.

  17. The chemical reactivity and structure of collagen studied by neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Wess, T.J.; Wess, L.; Miller, A. [Univ. of Stirling (United Kingdom)

    1994-12-31

    The chemical reactivity of collagen can be studied using neutron diffraction (a non-destructive technique), for certain reaction types. Collagen contains a number of lysine and hydroxylysine side chains that can react with aldehydes and ketones, or these side chains can themselves be converted to aldehydes by lysyl oxidase. The reactivity of these groups not only has an important role in the maintenance of mechanical strength in collagen fibrils, but can also manifest pathologically in the cases of aging, diabetes (reactivity with a variety of sugars) and alcoholism (reactivity with acetaldehyde). The reactivity of reducing groups with collagen can be studied by neutron diffraction, since the crosslink formed in the adduction process is initially of a Schiff base or keto-imine nature. The nature of this crosslink allows it to be deuterated, and the position of this relatively heavy scattering atom can be used in a process of phase determination by multiple isomorphous replacement. This process was used to study the following: the position of natural crosslinks in collagen; the position of adducts in tendon from diabetic rats in vivo and the in vitro position of acetaidehyde adducts in tendon.

  18. Precision cosmology defeats void models for acceleration

    OpenAIRE

    Moss, Adam; Zibin, James P.; Scott, Douglas

    2010-01-01

    The suggestion that we occupy a privileged position near the centre of a large, nonlinear, and nearly spherical void has recently attracted much attention as an alternative to dark energy. Putting aside the philosophical problems with this scenario, we perform the most complete and up-to-date comparison with cosmological data. We use supernovae and the full cosmic microwave background spectrum as the basis of our analysis. We also include constraints from radial baryonic acoustic oscillations...

  19. X-ray Computed Tomography Assessment of Air Void Distribution in Concrete

    Science.gov (United States)

    Lu, Haizhu

    Air void size and spatial distribution have long been regarded as critical parameters in the frost resistance of concrete. In cement-based materials, entrained air void systems play an important role in performance as related to durability, permeability, and heat transfer. Many efforts have been made to measure air void parameters in a more efficient and reliable manner in the past several decades. Standardized measurement techniques based on optical microscopy and stereology on flat cut and polished surfaces are widely used in research as well as in quality assurance and quality control applications. Other more automated methods using image processing have also been utilized, but still starting from flat cut and polished surfaces. The emergence of X-ray computed tomography (CT) techniques provides the capability of capturing the inner microstructure of materials at the micrometer and nanometer scale. X-ray CT's less demanding sample preparation and capability to measure 3D distributions of air voids directly provide ample prospects for its wider use in air void characterization in cement-based materials. However, due to the huge number of air voids that can exist within a limited volume, errors can easily arise in the absence of a formalized data processing procedure. In this study, air void parameters in selected types of cement-based materials (lightweight concrete, structural concrete elements, pavements, and laboratory mortars) have been measured using micro X-ray CT. The focus of this study is to propose a unified procedure for processing the data and to provide solutions to deal with common problems that arise when measuring air void parameters: primarily the reliable segmentation of objects of interest, uncertainty estimation of measured parameters, and the comparison of competing segmentation parameters.

  20. Evaluation of School Children%u2019s Voiding Problems in Sakarya Region

    Directory of Open Access Journals (Sweden)

    Adil Sonbahar

    2014-03-01

    Full Text Available Aim: Our goal was to determine the types of voiding problems of children%u2019s between 6 and 15 years old in Sakarya region. Material and Method: Totally 3246, 5-16 years old student randomly selected from 8 schools inside province. Students are evaluated in an appropriate room at school with a form pre-prepared in our clinic. Results: The survey shows that 486 of 3246 students (15% have voiding problems. The prevalance of dysfunctional voiding problems in all children, was 11.2%(365, nocturia prevalence was 8.7% (279, diurnal enuresis was 1% (32. In boys (totally 1573 the prevalance of dysfunctional voiding problems was 9% (145, nocturia prevalence was 11.7%(184, enuresis nocturia prevalence 11.2% (176, diurnal enuresis was 0.5% (8. In girls (totally 1673 the prevalance of dysfunctional voiding problems was 13.4 (223, nocturia prevalence was 6.7% (111, enuresis nocturia prevalence was 6.2% (103, diurnal enuresis prevalance was 1.4% (24. There was no meaningful statistical difference from the perspective of height and body mass index (BMI between the children with voiding problems and without any problem (p>0.05 . Discussion: The results for enuresis nocturna, nocturia and diurnal enuresis we have got from our study, are similar to ones that have been done in our country before. There is no data for prevalence od dysfunctional voiding study so far. Dysfunctional voiding problems in girls and in children who are in first years of school are more frequent.

  1. Generation, structure and reactivity of arynes: A theoretical study

    Indian Academy of Sciences (India)

    For case 4c, the electron-donating resonance effect of Z makes the p-carbon more negative than the m-one thereby leading to preferential attack of the nucleophile at the m-position. In the 3,4-pyridyne case of 4d, the p-carbon is activated towards nucleophilic attack, resulting in a p-substituted product. 1.5 Scope of this study.

  2. ESR, electrochemical and reactivity studies of antitrypanosomal palladium thiosemicarbazone complexes.

    Science.gov (United States)

    Otero, Lucía; Folch, Christian; Barriga, Germán; Rigol, Carolina; Opazo, Lucia; Vieites, Marisol; Gambino, Dinorah; Cerecetto, Hugo; Norambuena, Ester; Olea-Azar, Claudio

    2008-08-01

    Cyclic voltammetry (CV) and electron spin resonance (ESR) techniques were used in the investigation of novel palladium complexes with bioactive thiosemicarbazones derived from 5-nitrofurane or 5-nitrofurylacroleine. Sixteen palladium complexes grouped in two series of the formula [PdCl(2)HL] or [PdL(2)] were studied. ESR spectra of the free radicals obtained by electrolytic reduction were characterized and analyzed. The ESR spectra showed two different hyperfine patterns. The stoichiometry of the complexes does not seem to affect significantly the hyperfine constants however we observed great differences between 5-nitrofurane and 5-nitrofurylacroleine derivatives. The scavenger properties of this family of compounds were lower than Trolox.

  3. ESR, electrochemical and reactivity studies of antitrypanosomal palladium thiosemicarbazone complexes

    Science.gov (United States)

    Otero, Lucía; Folch, Christian; Barriga, Germán; Rigol, Carolina; Opazo, Lucia; Vieites, Marisol; Gambino, Dinorah; Cerecetto, Hugo; Norambuena, Ester; Olea-Azar, Claudio

    2008-08-01

    Cyclic voltammetry (CV) and electron spin resonance (ESR) techniques were used in the investigation of novel palladium complexes with bioactive thiosemicarbazones derived from 5-nitrofurane or 5-nitrofurylacroleine. Sixteen palladium complexes grouped in two series of the formula [PdCl 2HL] or [PdL 2] were studied. ESR spectra of the free radicals obtained by electrolytic reduction were characterized and analyzed. The ESR spectra showed two different hyperfine patterns. The stoichiometry of the complexes does not seem to affect significantly the hyperfine constants however we observed great differences between 5-nitrofurane and 5-nitrofurylacroleine derivatives. The scavenger properties of this family of compounds were lower than Trolox.

  4. Study of a composite from reactive blending of methylol urea resin ...

    African Journals Online (AJOL)

    This study was designed to study some physical properties of a composite derivable from reactive blending of methylol urea resin (MUR) with natural rubber (NR). Formaldehyde emission, decreased with increase in NR concentration in the blend. Elongation at break and viscosity recorded an initial increase but gradually ...

  5. M-CHOLINOLYTICS IN RHEABILITATION OF CHILDREN WITH VOIDING DISFUNCTION AND URNARY BLADDER HYPERACTIVITY

    Directory of Open Access Journals (Sweden)

    I.V. Kazanskaya

    2006-01-01

    Full Text Available Voiding dysfunction is a common problem in pediatrics. Hyperactive urinary bladder is the most frequent cause of voiding dysfunction. Macholinolytic drugs are the first choice treatment for urinary bladder hyperactivity. The «urination pathology» center has investigated the efficacy of an macholinolytic, oxybutynin. The study included 25 children (aged 6–14 with different causes of voiding dysfunction and bladder hyperactivity. Oxybutynin was administered with a dosage of 5 mg twice a day, the follow up period was 8 weeks. The control evaluation of urodynamics (voiding rhythm, uroflowmetry, residual urine volume was performed at 4–8 weeks. Symptoms of bladder hyperactivity have been eliminated in 50% of patients, the bladder capacity has increased in 70% of cases, the frequency of night and day incontinence has diminished. The report demonstrates that oxybutynin has been most effective in patients with urinary bladder volume between 80 and 100 ml. the side effects, as dryness of mucous membranes and voiding difficulties, have been rarely observed. These side effects could be avoided by individual dose titration.Key words: voiding dysfunction, urinary bladder hyperactivity, oxybutynin, children.

  6. Study of cardiovascular reactivity to mental stress in different phases of menstrual cycle.

    Science.gov (United States)

    Shenoy, Jnaneshwara P; Pa, Sahana; J, Shivakumar

    2014-06-01

    It is a well known fact that normally female sex hormone levels fluctuate during the menstrual cycle. The presence of receptors for these hormones on both heart and blood vessels may also hint at variations in physiological functions during menstrual cycle. So this study was an attempt to determine whether the follicular and luteal phases of menstrual cycle are characterized by variations in cardiovascular parameters in the resting state and also examine changes in cardiovascular reactivity to mental stress challenge during both the phases of menstrual cycle. Thirty healthy females in the age group of 18-25 years with regular menstrual cycles fulfilling the inclusion criteria were examined for cardiovascular parameters (heart rate and blood pressures) at rest and their reactivity to mental stress during the follicular and luteal phase and were compared by using paired t-test. A p-value of stress, in terms of blood pressure and heart rate increases, but the two phases of menstrual cycle were indistinguishable in so far as reactivity patterns were considered. The resting values of these cardiovascular parameters were also alike during the two phases. We were unable to unearth any differences in resting and reactivity values of cardiovascular parameters during the course of a normal menstrual cycle. This shows that stress reactivity variations during different phases of menstrual cycle may not be due to variations in hormonal levels per se, but due to collusion of hormonal variations and unknown genetic influences.

  7. [Experimental study of immune reactivity in Swiss mice due to topical administration of three textile dyes].

    Science.gov (United States)

    Gavăt, C C; Lupuşoru, R V; Ghiciuc, Cristina Mihaela; Lupuşoru, Cătălina Elena

    2010-01-01

    Reactive Red 183, Reactive Red 2 and Reactive Blue 204 (red dye, green dye and blue dye) are three reactive dyes frequently used in textile industry. In some atmospheric conditions ( high temperature, perspiration, pH values, UV/IR radiations), some quantities of these hydrolyzed dyes, could pass from textile clothes directly into the human skin. There were used 4 groups of white Swiss mice (with similar weight and number of both sexes), control group and 3 groups, treated once daily with a retro-auricular application of different reactive dyes. After 14 days of treatment, blood samples were taken from retro-orbitary plexus to assess leukocyte count, phagocytic capacity of peripheral neutrophils, serum opsonic capacity, phagocyte capacity and bactericidal capacity of peritoneal macrophages, splenic T lymphocytes with rossetting capacity and spleen cells forming Jerne plaques. The retro-acuricular and latero-cervical nodes were weighted. Red dye did not influence the weight of the studied nodes, but determined statistically significant modifications on non-specific immune system parameters. Blue and grena dyes determined modifications of weight especially of retroauricular nodes. Grena dye determined important effects of non-specific immune system parameters (serum opsonic capacity, phagocyte capacity and bactericidal capacity of peritoneal macrophages). The blue dye did not determine a biological response. Red and green dye determined important effects on non-specific immune system parameters.

  8. A numerical study on the disturbance of explosive reactive armors to jet penetration

    Directory of Open Access Journals (Sweden)

    Xiang-dong Li

    2014-03-01

    Full Text Available The disturbance of flat and V-shaped sandwich reactive armor configurations to shaped-charge jet is studied by a numerical approach. The disturbing and cutting effects of the two reactive armor configurations to the jet are successfully captured. The predicted disturbance characteristics and patterns are in fairly good agreement with the X-ray photographic observations. The residual depth of penetration into a semi-infinitive homogeneous steel target behind the reactive armor is computed for a series of jet/armor parameters. For the flat configuration, it is demonstrated that the residual penetration depth is not significantly reduced for a normal impact while it is reduced up to 75% for an oblique impact. In comparison, the V-shaped configuration reduces the penetration depth of the jet to 90%, and it is observed that the penetration depth is not sensitive to the V-shaped angle.

  9. Study of the adsorption of reactive blue 50 on zero valent iron

    Directory of Open Access Journals (Sweden)

    D Sarangerel

    2014-12-01

    Full Text Available  In this study, removal efficiency of the Reactive blue 50 and adsorption mechanism on the zero valent iron were investigated. Reactive blue 50 which is used to wool and cashmere dyeing were selected due its non-biodegradable and metabolic stability. Zero valent iron particle has been synthesized by chemical method. A systematic characterization of zero valent iron was performed using X-ray diffractometer, scanning electron microscope and infrared spectrometer analysis. The optimal condition of adsorption was determined as initial reactive dye 50 concentration of 150 mg·L-1, zero valent iron mass of 0.2 g and solution pH of 6.0 at room temperature. At optimal condition, organic dye removal in a real wastewater sample from Tsombon Knit LLC was 99.5%.Mongolian Journal of Chemistry 15 (41, 2014, p21-26

  10. Voiding dysfunction in children aged five to 15 years

    Directory of Open Access Journals (Sweden)

    Karaklajić Dragana

    2004-01-01

    Full Text Available Voiding dysfunction in children was analyzed in 91 patients in a period from January 1st to October 1st 1998. Most of the patients had functional voiding disorder (92.31%, and only 7.69% manifested monosymptomatic night enuresis. The number of girls was bigger in the group of patients with voiding dysfunction while the boys were predominant in the group with mono-symptomatic nocturnal enuresis. More than a half of children with functional voiding disorder had repeated urinal infections (58.23%, incontinence (93.49%, need for urgent voiding (68.13%, and vesicoureteral reflux (47.61%. The most common type of voiding dysfunction was urge syndrome/urge incontinence. The incidence of dysfunctional voiding disorder was more often in children with scaring changes of kidney which were diagnosed by static scintigraphy.

  11. Reactivity and Regioselectivity in the Heck Reaction - A Hammett Study of 4-Substituted Styrenes

    DEFF Research Database (Denmark)

    Fristrup, Peter; Le Quement, Sebastian; Tanner, David Ackland

    2004-01-01

    The regioselectivity in the cationic Heck reaction of 4-substituted styrenes was addressed by a Hammett study. In this branching reaction, plots based on the substrate reactivity did not give meaningful data, whereas the product distribution was variable due to differing preferences for further...... substitution under the reaction conditions and, thus, unsuitable for Hammett plots. Mechanistically meaningful graphs were obtained by combination of the measured initial branching ratio with the approximately constant substrate reactivity. For the alpha-substitution a clear Hammett relation is observed...

  12. Emotional Reactivity, Regulation and Childhood Stuttering: A Behavioral and Electrophysiological Study

    Science.gov (United States)

    Arnold, Hayley S.; Conture, Edward G.; Key, Alexandra P. F.; Walden, Tedra

    2011-01-01

    The purpose of this preliminary study was to assess whether behavioral and psychophysiological correlates of emotional reactivity and regulation are associated with developmental stuttering, as well as determine the feasibility of these methods in preschool-age children. Nine preschool-age children who stutter (CWS) and nine preschool-age children…

  13. Loneliness and acute stress reactivity: A systematic review of psychophysiological studies.

    Science.gov (United States)

    Brown, Eoin G; Gallagher, Stephen; Creaven, Ann-Marie

    2017-11-20

    Physiological reactivity to acute stress has been proposed as a potential biological mechanism by which loneliness may lead to negative health outcomes such as cardiovascular disease. This review was conducted to investigate the association between loneliness and physiological responses to acute stress. A series of electronic databases were systematically searched (PsycARTICLES, PsycINFO, Medline, CINAHL Plus, EBSCOhost, PubMed, SCOPUS, Web of Science, Science Direct) for relevant studies, published up to October 2016. Eleven studies were included in the review. Overall, the majority of studies reported positive associations between loneliness and acute stress responses, such that higher levels of loneliness were predictive of exaggerated physiological reactions. However, in a few studies, loneliness was also linked with decreased stress responses for particular physiological outcomes, indicating the possible existence of blunted relationships. There was no clear pattern suggesting any sex- or stressor-based differences in these associations. The available evidence supports a link between loneliness and atypical physiological reactivity to acute stress. A key finding of this review was that greater levels of loneliness are associated with exaggerated blood pressure and inflammatory reactivity to acute stress. However, there was some indication that loneliness may also be related to blunted cardiac, cortisol, and immune responses. Overall, this suggests that stress reactivity could be one of the biological mechanisms through which loneliness impacts upon health. © 2017 Society for Psychophysiological Research.

  14. Atherosclerosis, C-reactive protein, and risk for open-angle glaucoma : The Rotterdam study

    NARCIS (Netherlands)

    de Voogd, Simone; Wolfs, Roger C. W.; Jansonius, Nomdo M.; Witteman, Jacqueline C. M.; Hofman, Albert; de Jong, Paulus T. V. M.

    PURPOSE. To test the hypotheses that atherosclerosis and elevated serum C-reactive protein ( CRP) levels are risk factors for open-angle glaucoma ( OAG). METHODS. In a prospective, population-based cohort study, all participants 55 years and older and at risk for incident OAG underwent, at baseline

  15. Atherosclerosis, C-reactive protein, and risk for open-angle glaucoma: The Rotterdam Study

    NARCIS (Netherlands)

    S. de Voogd (Simone); R.C.W. Wolfs (Roger); N.M. Jansonius (Nomdo); J.C.M. Witteman (Jacqueline); A. Hofman (Albert); P.T.V.M. de Jong (Paulus)

    2006-01-01

    textabstractPURPOSE. To test the hypotheses that atherosclerosis and elevated serum C-reactive protein (CRP) levels are risk factors for open-angle glaucoma (OAG). METHODS. In a prospective, population-based cohort study, all participants 55 years and older and at risk for incident OAG underwent, at

  16. Atherosclerosis, C-reactive protein, and risk for open-angle glaucoma: the Rotterdam study

    NARCIS (Netherlands)

    de Voogd, Simone; Wolfs, Roger C. W.; Jansonius, Nomdo M.; Witteman, Jacqueline C. M.; Hofman, Albert; de Jong, Paulus T. V. M.

    2006-01-01

    To test the hypotheses that atherosclerosis and elevated serum C-reactive protein (CRP) levels are risk factors for open-angle glaucoma (OAG). In a prospective, population-based cohort study, all participants 55 years and older and at risk for incident OAG underwent, at baseline (1990-1993) and at

  17. Vacancy Migration and Void Formation in gamma-irradiated Ice

    DEFF Research Database (Denmark)

    Eldrup, Morten Mostgaard

    1976-01-01

    are ascribed to Ps inhibition and conversion by radiation created OH radicals. Heating above −165°C makes both effects disappear in agreement with radiation chemistry results on OH. Heating also increases the longest lifetime up to 11 nsec at −130°C. This is explained as vacancy migration leading to void...... formation. A vacancy migration energy is obtained, Em=0.34±0.07 eV, around three times higher than the previously assumed value. The advantage in this kind of study of using PAT, which are specifically sensitive to vacancy type defects, is pointed out....

  18. Tensor anisotropy as a tracer of cosmic voids

    Science.gov (United States)

    Bustamante, Sebastian; Forero-Romero, Jaime E.

    2015-10-01

    We present a new method to find voids in cosmological simulations based on the tidal and the velocity shear tensors definitions of the cosmic web. We use the fractional anisotropy (FA) computed from the eigenvalues of each web scheme as a void tracer. We identify voids using a watershed transform based on the local minima of the FA field without making any assumption on the shape or structure of the voids. We test the method on the Bolshoi simulation and report on the abundance and radial averaged profiles for the density, velocity and FA. We find that voids in the velocity shear web are smaller than voids in the tidal web, with a particular overabundance of very small voids in the inner region of filaments/sheets. We classify voids as subcompensated/overcompensated depending on the absence/presence of an overdense matter ridge in their density profile, finding that close to 65 and 35 per cent of the total population are classified into each category, respectively. Finally, we find evidence for the existence of universal profiles from the radially averaged profiles for density, velocity and FA. This requires that the radial coordinate is normalized to the effective radius of each void. Put together, all these results show that the FA is a reliable tracer for voids, which can be used in complementarity to other existing methods and tracers.

  19. Morphological Segregation in the Surroundings of Cosmic Voids

    Energy Technology Data Exchange (ETDEWEB)

    Ricciardelli, Elena; Tamone, Amelie [Laboratoire d’Astrophysique, École Polytechnique Fédérale de Lausanne (EPFL), 1290 Sauverny (Switzerland); Cava, Antonio [Observatoire de Genève, Université de Genève, 51 Ch. des Maillettes, 1290 Versoix (Switzerland); Varela, Jesus, E-mail: elena.ricciardelli@epfl.ch [Centro de Estudios de Física del Cosmos de Aragón (CEFCA), Plaza San Juan 1, E-44001 Teruel (Spain)

    2017-09-01

    We explore the morphology of galaxies living in the proximity of cosmic voids, using a sample of voids identified in the Sloan Digital Sky Survey Data Release 7. At all stellar masses, void galaxies exhibit morphologies of a later type than galaxies in a control sample, which represent galaxies in an average density environment. We interpret this trend as a pure environmental effect, independent of the mass bias, due to a slower galaxy build-up in the rarefied regions of voids. We confirm previous findings about a clear segregation in galaxy morphology, with galaxies of a later type being found at smaller void-centric distances with respect to the early-type galaxies. We also show, for the first time, that the radius of the void has an impact on the evolutionary history of the galaxies that live within it or in its surroundings. In fact, an enhanced fraction of late-type galaxies is found in the proximity of voids larger than the median void radius. Likewise, an excess of early-type galaxies is observed within or around voids of a smaller size. A significant difference in galaxy properties in voids of different sizes is observed up to 2 R {sub void}, which we define as the region of influence of voids. The significance of this difference is greater than 3 σ for all the volume-complete samples considered here. The fraction of star-forming galaxies shows the same behavior as the late-type galaxies, but no significant difference in stellar mass is observed in the proximity of voids of different sizes.

  20. Morphological Segregation in the Surroundings of Cosmic Voids

    Science.gov (United States)

    Ricciardelli, Elena; Cava, Antonio; Varela, Jesus; Tamone, Amelie

    2017-09-01

    We explore the morphology of galaxies living in the proximity of cosmic voids, using a sample of voids identified in the Sloan Digital Sky Survey Data Release 7. At all stellar masses, void galaxies exhibit morphologies of a later type than galaxies in a control sample, which represent galaxies in an average density environment. We interpret this trend as a pure environmental effect, independent of the mass bias, due to a slower galaxy build-up in the rarefied regions of voids. We confirm previous findings about a clear segregation in galaxy morphology, with galaxies of a later type being found at smaller void-centric distances with respect to the early-type galaxies. We also show, for the first time, that the radius of the void has an impact on the evolutionary history of the galaxies that live within it or in its surroundings. In fact, an enhanced fraction of late-type galaxies is found in the proximity of voids larger than the median void radius. Likewise, an excess of early-type galaxies is observed within or around voids of a smaller size. A significant difference in galaxy properties in voids of different sizes is observed up to 2 R void, which we define as the region of influence of voids. The significance of this difference is greater than 3σ for all the volume-complete samples considered here. The fraction of star-forming galaxies shows the same behavior as the late-type galaxies, but no significant difference in stellar mass is observed in the proximity of voids of different sizes.

  1. Geothermal Fluid Interaction with Mafic Rocks in Porous Media - AN Experimental and Reactive Transport Modeling Study

    Science.gov (United States)

    Stefansson, A.

    2013-12-01

    Reaction and reactive transport modeling is becoming an increasingly popular method to study fluid-rock interaction and fluid transport on small to large scales. In this study, fluid-rock experiments were carried out and the observations compared with the results of reaction and reactive transport models. The systems studied included fluid-rock interaction of olivine on one hand and basaltic glass on the other hand with dilute aqueous solutions containing CO2 at acid to neutral pH and temperatures from ambient to 250 °C. The experiments were conducted using batch type experiments in closed reactors and 1-D plug experiments in flow-through reactors and the solution chemistry, the reaction progress, secondary mineralization and porosity changes analyzed as a function of time. The reaction and 1-D reactive transport simulations were conducted with the aid of the PHREEQC program. For the simulations the thermodynamic database for mineral reactions was largely updated and the kinetics of mineral dissolution as well as mineral nucleation and crystal growth was incorporated. According to the experimental results and the reactive transport simulations, olivine and basaltic glass progressively dissolves forming secondary minerals and solutes that are partially transported out of them column (system). The exact reaction path was found to depend on solution composition and pH and reaction progress (time). The mass movement of the system at a particular steady state as well as porosity changes may be divided into three stages. Stage I is characterized by initial olivine or basaltic glass leaching, stage II is characterized by progressive mineral formation and decrease in porosity and stage III is characterized by remobilization of the previously formed secondary minerals and eventual increase in porosity. The reaction and reactive transport modeling was found to simulate reasonable the reaction path as a function of reaction time. However, exact mass movement and time

  2. Nicotine deprivation attenuates panic reactivity in smokers: Findings from a placebo-controlled nicotine patch study.

    Science.gov (United States)

    Abrams, Kenneth; Krimmel, Sam; Johnson, Stacey; Cieslowski, Kate; Strnad, Helen; Melum, Arielle; Kryder, Caroline

    2017-11-01

    Prospective studies consistently find that smoking is a risk factor for the development of panic disorder (PD). A possible explanation is that nicotine deprivation promotes heightened sensitivity to bodily sensations and/or arterial carbon dioxide (CO 2 ). Abrams et al. (2011) previously found that, in response to a CO 2 rebreathing challenge, smokers experiencing more (vs. less) intense nicotine withdrawal had more severe panic symptoms and a stronger urge to escape. However, participants were aware of the last time they smoked, leaving unclear the extent to which fear reactivity was influenced by the pharmacologic effects of nicotine deprivation versus beliefs regarding when nicotine was most recently used. The present study aimed to ascertain whether nicotine deprivation, independent of beliefs regarding recent nicotine use, promotes fear reactivity among smokers. Moderate to heavy smokers without PD (N = 25) participated in a placebo-controlled, double-blind study consisting of two sessions spaced 1 week apart. Participants abstained from nicotine for 2 hr prior to sessions. During one session participants were given a 21 mg nicotine replacement patch and, during the other, a placebo patch, with the order counterbalanced. For both sessions, after a 3-hr absorption period, participants underwent a 10-min CO 2 rebreathing challenge. Wearing a nicotine (vs. placebo) patch increased self-reported panic reactivity among participants, but did not significantly affect physiological and behavioral measures of reactivity. In smokers without a history of PD, nicotine deprivation attenuates subjective panic reactivity. Possible explanations for the contrast between theory and laboratory findings as well as clinical implications are discussed. © 2017 Wiley Periodicals, Inc.

  3. Reactivity in Rapidly Collected Hygiene and Toilet Spot Check Measurements: A Cautionary Note for Longitudinal Studies

    Science.gov (United States)

    Arnold, Benjamin F.; Khush, Ranjiv S.; Ramaswamy, Padmavathi; Rajkumar, Paramasivan; Durairaj, Natesan; Ramaprabha, Prabhakar; Balakrishnan, Kalpana; Colford Jr., John M.

    2015-01-01

    Discreet collection of spot check observations to measure household hygiene conditions is a common measurement technique in epidemiologic studies of hygiene in low-income countries. The objective of this study was to determine whether the collection of spot check observations in longitudinal studies could itself induce reactivity (i.e., change participant behavior). We analyzed data from a 12-month prospective cohort study in rural Tamil Nadu, India that was conducted in the absence of any hygiene or toilet promotion activities. Our data included hygiene and toilet spot checks from 10,427 household visits. We found substantial evidence of participant reactivity to spot check observations of hygiene practices that were easy to modify on short notice. For example, soap observed at the household's primary handwashing location increased from 49% at enrollment to 81% by the fourth visit and remained at or above 77% for the remainder of the study. PMID:25385856

  4. Computational Study of Chemical Reactivity Using Information-Theoretic Quantities from Density Functional Reactivity Theory for Electrophilic Aromatic Substitution Reactions.

    Science.gov (United States)

    Wu, Wenjie; Wu, Zemin; Rong, Chunying; Lu, Tian; Huang, Ying; Liu, Shubin

    2015-07-23

    The electrophilic aromatic substitution for nitration, halogenation, sulfonation, and acylation is a vastly important category of chemical transformation. Its reactivity and regioselectivity is predominantly determined by nucleophilicity of carbon atoms on the aromatic ring, which in return is immensely influenced by the group that is attached to the aromatic ring a priori. In this work, taking advantage of recent developments in quantifying nucleophilicity (electrophilicity) with descriptors from the information-theoretic approach in density functional reactivity theory, we examine the reactivity properties of this reaction system from three perspectives. These include scaling patterns of information-theoretic quantities such as Shannon entropy, Fisher information, Ghosh-Berkowitz-Parr entropy and information gain at both molecular and atomic levels, quantitative predictions of the barrier height with both Hirshfeld charge and information gain, and energetic decomposition analyses of the barrier height for the reactions. To that end, we focused in this work on the identity reaction of the monosubstituted-benzene molecule reacting with hydrogen fluoride using boron trifluoride as the catalyst in the gas phase. We also considered 19 substituting groups, 9 of which are ortho/para directing and the other 9 meta directing, besides the case of R = -H. Similar scaling patterns for these information-theoretic quantities found for stable species elsewhere were disclosed for these reactions systems. We also unveiled novel scaling patterns for information gain at the atomic level. The barrier height of the reactions can reliably be predicted by using both the Hirshfeld charge and information gain at the regioselective carbon atom. The energy decomposition analysis ensued yields an unambiguous picture about the origin of the barrier height, where we showed that it is the electrostatic interaction that plays the dominant role, while the roles played by exchange-correlation and

  5. Sacral Herpes Zoster Associated with Voiding Dysfunction in a Young Patient with Scrub Typhus

    Science.gov (United States)

    2015-01-01

    When a patient presents with acute voiding dysfunction without a typical skin rash, it may be difficult to make a diagnosis of herpes zoster. Here, we present a case of scrub typhus in a 25-year-old man with the complication of urinary dysfunction. The patient complained of loss of urinary voiding sensation and constipation. After eight days, he had typical herpes zoster eruptions on the sacral dermatomes and hypalgesia of the S1-S5 dermatomes. No cases of dual infection with varicella zoster virus and Orientia tsutsugamushi were found in the literature. In the described case, scrub typhus probably induced sufficient stress to reactivate the varicella zoster virus. Early recognition of this problem is imperative for prompt and appropriate management, as misdiagnosis can lead to long-term urinary dysfunction. It is important that a diagnosis of herpes zoster be considered, especially in patients with sudden onset urinary retention. PMID:26157595

  6. An axially multilayered low void worth liquid-metal fast breeder reactor core concept

    Energy Technology Data Exchange (ETDEWEB)

    Kamei, T.; Yamaoka, M. (Toshiba Corp., Nuclear Engineering Lab., 4-1 Ukishima-cho, Kawasaki-ku, Kawasaki-shi 210 (JP))

    1992-03-01

    A new core concept with a negative sodium void reactivity coefficient has evolved. The core is composed of two core layers in the axial direction. The core layers are separated by an internal blanket, the central region of which comprises a neutron-absorbing material such as boron carbide or tantalum. Consequently, the two core layers are completely decoupled as regards neutronics, leading to an effective increase in neutron leakage from the core region when sodium is voided. This design is expected to be free from the disadvantages of a large core radius, as seen in a conventional spoiled core such as a pancake core. In this paper the design is described in detail, and its application to a 300-MW (electronic) metal fuel core and to a 450-MW (electric) minor actinide burned core is given as an example.

  7. Void formation in ODS EUROFER produced by hot isostatic pressing

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, Y.; Monge, M.A.; Munoz, A.; Leguey, T.; Pareja, R. [Madrid Univ. Carlos-3, Dept. de Fisica (Spain); Castro, V. de [Oxford Univ., Dept. of Materials (United Kingdom)

    2007-07-01

    Full text of publication follows: An obstacle in the development of oxide dispersion strengthened (ODS) steels for structural applications in fusion reactors is the toughness lack of the material produced by powder metallurgy and consolidated by hot isostatic pressing (HIP). In particular, ODS EUROFER steel with Y{sub 2}O{sub 3} particles appears to exhibit poor impact properties. To asses the capabilities of this material, it is necessary elucidate if its failure is an inherent characteristic of the production process that can not be mitigated by normalizing and tempering treatments. In order to investigate this particular point, the evolution of the structural defects retained in the ODS material during isochronal annealing has been probed by positron annihilation spectroscopy. The present study has been performed on bail milled EUROFER powders consolidated by HIP, containing 0.25 wt % Y{sub 2}O{sub 3} and without Y{sub 2}O{sub 3}. For comparison, un-milled EUROFER powder consolidated under identical conditions, and as-received EUROFER97 plate produced by Boehler AG have been also investigated. Samples from these four materials were isochronally annealed for 90 min up to 1323 K. Materials produced from milled powders had a longer positron lifetime than the one produced from un-milled powder or the EUROFER plate. In the material containing Y{sub 2}O{sub 3}, i.e. in ODS EUROFER, annealing above 723 K produced a continuous increase in the mean positron lifetime <{tau}> up to reach a maximum value of 208 ps after annealing at 1223 K. A similar annealing behavior was observed for Y{sub 2}O{sub 3}-free milled EUROFER (milled EUROFER), but the <{tau}> value steeply changed from {approx}160 ps at 823 K to {approx}200 ps after annealing at 1023 K. Subsequent anneals above this temperature produced meaningless changes in <{tau}>. The <{tau}> increase in milled EUROFER was accompanied by the intensity increase of a lifetime component of {approx}360 ps that is characteristic

  8. Comparative Study of Personality Trait Characteristics and Reactivity in Schizophrenia Using a Film Clip Paradigm.

    Science.gov (United States)

    Dinzeo, Thomas J; Sledjeski, Eve; Durner, Christopher; Docherty, Nancy M

    2015-01-01

    The empirical examination of personality characteristics related to the experience of strong negative emotions and the associated physiological response may help account for idiosyncratic responses to life events in schizophrenia. The current study examines the relationship between levels of neuroticism and arousability and physiological and emotional reactivity during the viewing of film clips with differing emotional valance. Data were collected on emotional and cardiovascular and cortisol reactivity across experimental conditions for a sample of outpatients diagnosed with schizophrenia and a comparison group of nonpsychiatric controls. Levels of both neuroticism and arousability were significantly associated with increased negative emotion and physiological reactivity during the negative film clip task, although different patterns emerged across participant groups. Most notably, trait characteristics were inversely related to heart rate reactivity in patients but not controls. This relationship remained significant even after we controlled for disengagement coping behaviors. Cortisol response was not related to personality characteristics in either participant group. Findings were generally consistent with previous research, providing additional evidence for the role of trait characteristics in the response to events.

  9. Thermogravimetric study on the hydration of reactive magnesia and silica mixture at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Fei, E-mail: fj232@cam.ac.uk; Al-Tabbaa, Abir

    2013-08-20

    Highlights: • The characteristics of reactive MgO vary significantly in terms of their impurity content and reactivity depending on their sources and calcination conditions. • The synthesis of magnesium silicate hydrate (MSH) is affected by the characteristics of the precursors, i.e., MgO and silica. • The reaction process in the MgO–SiO{sub 2}–H{sub 2}O system can be followed by TGA, and is essential to develop MSH-based materials. - Abstract: The synthesis of magnesium silicate hydrate (MSH), which has wide applications in both construction and environmental fields, has been studied for decades. However, it is known that the characteristics of magnesia (MgO) vary significantly depending on their calcination conditions, which is expected to affect their performance in the MgO–SiO{sub 2}–H{sub 2}O system. This paper investigated the effect of different MgO and silica sources on the formation of magnesium silicate hydrate (MSH) at room temperature. The hydration process was studied by mixing commercial reactive MgO and silica powders with water and curing for 1, 7 and 28 days. The hydration products were analysed with the help of X-ray diffraction (XRD) and thermogravimatric analysis (TGA). The results showed the continuous consumption of MgO and the existence of MSH and brucite and other minor phases such as magnesite and calcite. It is found that the Mg and Si sources have significant effect on the hydration process of MgO–SiO{sub 2}–H{sub 2}O system. The reaction degree is controlled by the availability of dissolved Mg and Si in the solution. The former is determined by the reactivity of MgO and the latter is related to the reactivity of the silica as well as the pH of the system.

  10. Study of effects of metformin on C-reactive protein level in Type-2 diabetes mellitus

    OpenAIRE

    Niteshkumar C. Gamit; Naresh D. Kantharia; Khushbu B. Vaghasiya; Ankit J. Vataliya; Aashal B. Shah

    2015-01-01

    Background: Diabetes mellitus (DM) is extremely common; represent a significant global health problem. Type-2 DM is considered to be associated with a low grade inflammation, which may play a significant role in development of cardiovascular complications evidenced by C-reactive protein (CRP) is a an extremely sensitive marker of systemic inflammation. The study was undertaken to check the effect of metformin on CRP level in Type-2 DM. Methods: The study was prospective and non-randomized....

  11. The association of age of toilet training and dysfunctional voiding.

    Science.gov (United States)

    Hodges, Steve J; Richards, Kyle A; Gorbachinsky, Ilya; Krane, L Spencer

    2014-01-01

    To determine whether age of toilet training is associated with dysfunctional voiding in children. We compared patients referred to the urologic clinics for voiding dysfunction with age-matched controls without urinary complaints. Characteristics including age and reason for toilet training, method of training, and encopresis or constipation were compared between both groups. Initiation of toilet training prior to 24 months and later than 36 months of age were associated with dysfunctional voiding. However, dysfunctional voiding due to late toilet training was also associated with constipation. Dysfunctional voiding may be due to delayed emptying of the bowel and bladder by children. The symptoms of dysfunctional voiding are more common when toilet training early, as immature children may be less likely to empty in a timely manner, or when training late due to (or in association with) constipation.

  12. Trampoline effect and the force field inside the void in complex plasma under microgravity conditions

    Energy Technology Data Exchange (ETDEWEB)

    Khrapak, S. A.; Kretschmer, M.; Zhdanov, S. K.; Thomas, H. M.; MOrfill, G. e.; Fortov, V. E.; Lipaev, A. M.; Molotkov, V. I.; Ivanov, A. I.; Turin, M. V.

    2005-07-01

    The PKE-Nefedov facility onboard the International Space Station (ISS),operational since March, 2'001, has enabled the study of complex (dusty) plasmas under microgravity conditions. A complex plasma is generated by introducing micron sized grains in a capacitively coupled rf discharge. The grains form a cloud inside the bulk of the discharge and can be easily visualized with the help of standard tools-laser illumination and video cameras. In most of the experiments under microgravity conditions the central region of the discharge is free of grains a so called void is formed. Due to recent theoretical advances, showing that the ion drag force can be more than a factor of ten larger than had traditionally been believed, void formation is now through to be a consequence of this (enhanced) interaction. The way this process works is the following: the ions drifting from the central region of a discharge to its walls and electrodes transfer their momentum to the grains pushing them out of the center. However, no direct experimental results on the origin of the void formation were reported so far. In this paper we report new results on the observation of a weak instability of the void-complex plasma interface observed at a relatively low gas pressure (p=12Pa). The instability leads to periodic injections of a relatively small number of particles into the void region (by analogy this effect is called trampoline effect), The trajectories of injected particles are analyzed providing information on the force field and potential energy distribution inside the void. For the relatively low neutral gas pressure used in the experiment a direct comparison with theory involving a model of the ion drag force in the collisionless regime is possible. Such a comparison yields good agreement, implying that we have observed the first experimental confirmation of the ion drag mechanism as being responsible for the void formation. (Author)

  13. The mechanism and kinetics of void formation and growth in particulate filled PE composites

    Directory of Open Access Journals (Sweden)

    2007-11-01

    Full Text Available Volume strain measurements were carried out on PE/CaCO3 composites prepared with three different matrix polymers, containing various amounts of filler. The analysis of the debonding process and the various stages of void formation proved that the model developed for the prediction of the initiation of debonding is valid also for the studied PE/CaCO3 composites. Debonding stress is determined by the strength of interfacial adhesion, particle size and the stiffness of the matrix. In thermoplastic matrices usually two competitive processes take place: debonding and the plastic deformation of the polymer. The relative magnitude of the two processes strongly influences the number and size of the voids formed. Because of this competition and due to the wide particle size distribution of commercial fillers, only a certain fraction of the particles initiate the formation of voids. The number of voids formed is inversely proportional to the stiffness of the matrix polymer. In stiff matrices almost the entire amount of filler separates from the matrix under the effect of external load, while less than 30% debond in a PE which has an initial modulus of 0.4 GPa. Further decrease of matrix stiffness may lead to the complete absence of debonding and the composite would deform exclusively by shear yielding. Voids initiated by debonding grow during the further deformation of the composite. The size of the voids also depends on the modulus of the matrix. The rate of volume increase considerably exceeds the value predicted for cross-linked rubbers. At the same deformation and filler content the number of voids is smaller and their size is larger in soft matrices than in polymers with larger inherent modulus.

  14. Ab initio studies of equations of state and chemical reactions of reactive structural materials

    Science.gov (United States)

    Zaharieva, Roussislava

    subject of studies of the shock or thermally induced chemical reactions of the two solids comprising these reactive materials, from first principles, is a relatively new field of study. The published literature on ab initio techniques or quantum mechanics based approaches consists of the ab initio or ab initio-molecular dynamics studies in related fields that contain a solid and a gas. One such study in the literature involves a gas and a solid. This is an investigation of the adsorption of gasses such as carbon monoxide (CO) on Tungsten. The motivation for these studies is to synthesize alternate or synthetic fuel technology by Fischer-Tropsch process. In this thesis these studies are first to establish the procedure for solid-solid reaction and then to extend that to consider the effects of mechanical strain and temperature on the binding energy and chemisorptions of CO on tungsten. Then in this thesis, similar studies are also conducted on the effect of mechanical strain and temperature on the binding energies of Titanium and hydrogen. The motivations are again to understand the method and extend the method to such solid-solid reactions. A second motivation is to seek strained conditions that favor hydrogen storage and strain conditions that release hydrogen easily when needed. Following the establishment of ab initio and ab initio studies of chemical reactions between a solid and a gas, the next step of research is to study thermally induced chemical reaction between two solids (Ni+Al). Thus, specific new studies of the thesis are as follows: (1) Ab initio Studies of Binding energies associated with chemisorption of (a) CO on W surfaces (111, and 100) at elevated temperatures and strains and (b) adsorption of hydrogen in titanium base. (2) Equations of state of mixtures of reactive material structures from ab initio methods. (3) Ab initio studies of the reaction initiation, transition states and reaction products of intermetallic mixtures of (Ni+Al) at elevated

  15. Adopted Children's Language Difficulties and Their Relation to Symptoms of Reactive Attachment Disorder: FinAdo Study

    Science.gov (United States)

    Raaska, Hanna; Elovainio, Marko; Sinkkonen, Jari; Stolt, Suvi; Jalonen, Iina; Matomaki, Jaakko; Makipaa, Sanna; Lapinleimu, Helena

    2013-01-01

    This study investigated the potential association between symptoms of reactive attachment disorder and language difficulties among internationally adopted children in Finland (the FinAdo study). The language difficulties were assessed using a standardised Five to Fifteen (FTF) parental questionnaire and the symptoms of reactive attachment disorder…

  16. Dislocation and void segregation in copper during neutron irradiation

    DEFF Research Database (Denmark)

    Singh, Bachu Narain; Leffers, Torben; Horsewell, Andy

    1986-01-01

    ); the irradiation experiments were carried out at 250 degree C. The irradiated specimens were examined by transmission electron microscopy. At both doses, the irradiation-induced structure was found to be highly segregated; the dislocation loops and segments were present in the form of irregular walls and the voids...... density, the void swelling rate was very high (approximately 2. 5% per dpa). The implications of the segregated distribution of sinks for void formation and growth are briefly discussed....

  17. Discharge Mechanism in Voids at Sub-Atmospheric Pressures

    OpenAIRE

    B.Ramachandra; Nema, RS

    1998-01-01

    The physical processes occurring during partial discharges (PD) in voids in solid dielectrics are complicated due to the lack of knowledge of void shape, location and gas pressure. Fast oscilloscopic techniques are needed to measure the build up and decay of current as a function of time for single discharges. The purpose of the present work is to investigate the mechanism of the discharge in artificial voids in thin polypropylene (PP) films at different sub-atmospheric pressures. Efforts hav...

  18. Dynamics of voids and their shapes in redshift space

    Science.gov (United States)

    Maeda, Kei-ichi; Sakai, Nobuyuki; Triay, Roland

    2011-08-01

    We investigate the dynamics of a single spherical void embedded in a Friedmann-Lemaȋtre universe, and analyze the void shape in the redshift space. We find that the void in the redshift space appears as an ellipse shape elongated along the line of sight (i.e., an opposite deformation to the Kaiser effect). Applying this result to observed void candidates at the redshift z ~ 1-2, it may provide us with a new method to evaluate the cosmological parameters, in particular the value of a cosmological constant.

  19. Near‐surface void detection using a seismic landstreamer and horizontal velocity and attenuation tomography

    Science.gov (United States)

    Buckley, Sean F.; Lane, John W.

    2012-01-01

    The detection and characterization of subsurface voids plays an important role in the study of karst formations and clandestine tunnels. Horizontal velocity and attenuation tomography (HVAT) using offset‐fan shooting and a towed seismic land streamer is a simple, rapid, minimally invasive method that shows promise for detecting near‐surface voids and providing information on the orientation of linear voids. HVAT surveys were conducted over a known subsurface steam tunnel on the University of Connecticut Depot Campus, Storrs, Connecticut. First‐arrival travel‐time and amplitude data were used to produce two‐dimensional (2D) horizontal (map view) velocity and attenuation tomograms. In addition, attenuation tomograms were produced based on normalized total trace energy (TTE). Both the velocity and TTE attenuation tomograms depict an anomaly consistent with the location and orientation of the known tunnel; the TTE method, however, requires significantly less processing time, and therefore may provide a path forward to semi‐automated, near real‐time detection of near‐surface voids. Further study is needed to assess the utility of the HVAT method to detect deeper voids and the effects of a more complex geology on HVAT results.

  20. Detection of Molecular Gas in Void Galaxies : Implications for Star Formation in Isolated Environments

    Science.gov (United States)

    Das, M.; Saito, T.; Iono, D.; Honey, M.; Ramya, S.

    2015-12-01

    We present the detection of molecular gas from galaxies located in nearby voids using the CO(1-0) line emission as a tracer. The observations were performed using the 45 m single dish radio telescope of the Nobeyama Radio Observatory. Void galaxies lie in the most underdense parts of our universe and a significant fraction of them are gas rich, late-type spiral galaxies. Although isolated, they have ongoing star formation but appear to be slowly evolving compared to galaxies in denser environments. Not much is known about their star formation properties or cold gas content. In this study, we searched for molecular gas in five void galaxies. The galaxies were selected based on their relatively high IRAS fluxes or Hα line luminosities, both of which signify ongoing star formation. All five galaxies appear to be isolated and two lie within the Bootes void. We detected CO(1-0) emission from four of the five galaxies in our sample and their molecular gas masses lie between 108 and 109 M⊙. We conducted follow-up Hα imaging observations of three detected galaxies using the Himalayan Chandra Telescope and determined their star formation rates (SFRs) from their Hα fluxes. The SFR varies from 0.2 to 1 M⊙ yr-1 which is similar to that observed in local galaxies. Our study indicates that although void galaxies reside in underdense regions, their disks contain molecular gas and have SFRs similar to galaxies in denser environments. We discuss the implications of our results.

  1. Study on Reactivity of Circulating Fluidized Bed Combustion Fly Ashes in the Presence of Water

    Directory of Open Access Journals (Sweden)

    Salain I.M.A.K.

    2010-01-01

    Full Text Available A study on reactivity of four different Circulating Fluidized Bed Combustion (CFBC fly ashes has been realized in the presence of water. Paste of each ash was prepared and analyzed for its setting time, expansion and strength. The products of hydration, and their evolutions over a period of time were identified by X-ray diffraction and differential thermal analysis. The results of this study show that the reactivity of the CFBC fly ashes is strongly related to their chemical composition, essentially to their quantity of silica, alumina, lime and sulfate, which promote principally the formation of ettringite, gypsum and C-S-H. It is further noted that the intensity and the proportion of these phases determine the hydration behavior of the CFBC fly ashes.

  2. Substitution Effects on Reactivity of N-Acyl-2-amino-2-desoxyglucopyranoses. Quantum Chemical Study

    Directory of Open Access Journals (Sweden)

    Gytis Vektaris

    2000-12-01

    Full Text Available Quantum mechanical calculations were carried out to study the molecular geometry and electronic structure of 2-amino-2-desoxyglucopyranose (AG and the Nacetyl-, N-ethanoyl-, series of N-phthalimidoalkanoyl-AG. The total charge density, electrostatic potential, spatial distribution and positions of HOMO and LUMO of N-acyl-AGs with respect to their substitutes yield information on the reactivity of the molecules.

  3. Personalized smoking environment cue reactivity in smokers with schizophrenia and controls: a pilot study

    OpenAIRE

    AhnAllen, Christopher G.; Tidey, Jennifer W.

    2011-01-01

    Exposure to smoking cues increases craving to smoke and negatively changes mood in smokers with schizophrenia (SWS). This pilot study compared reactivity to real-world smoking environments versus neutral environments in SWS (n = 10) and non-psychiatric control smokers (CON; n = 10). Results indicate that both SWS and CON experienced increases in smoking urges when viewing images of their smoking environments and that SWS tended to report greater increases in withdrawal-related negative mood t...

  4. Reactivity of Monolayer Protected Silver Clusters Towards Excess Ligand: A Calorimetric Study

    KAUST Repository

    Baksi, Ananya

    2017-10-31

    Reactivity of monolayer protected atomically precise clusters of noble metals is of significant research interest. Till date very few experimental data are available on the reaction thermodynamics of such clusters. Here we report a calorimetric study of the reaction of glutathione (GSH) protected silver clusters in presence of excess ligand, GSH using isothermal titration calorimetry (ITC). We have studied Ag11(SG)7 and Ag32(SG)19 clusters and compared their reactivity with GSH protected silver nanoparticles (AgNPs) and silver ions. Clusters show intermediate reactivity towards excess ligand com-pared to nanoparticles and silver ions. Several control experiments were performed to understand the degradation mech-anism of these silver clusters and nanoparticles. Effect of dissolved oxygen in the degradation process was studied in de-tail and found that it did not have a significant role, although alternate pathways of degradation with the involvement of oxygen cannot be ruled out. Direct confirmation of the fact that functionalized metal clusters fall in-between NPs and atomic systems in their stability is obtained experimentally for the first time. Several other thermophysical parameters of these clusters were also determined including, density, speed of sound, isentropic compressibility and coefficient of thermal expansion.

  5. Site reactivity in the free radicals induced damage to leucine residues: a theoretical study.

    Science.gov (United States)

    Medina, M E; Galano, A; Alvarez-Idaboy, J R

    2015-02-21

    Several recent computational studies have tried to explain the observed selectivity in radical damage to proteins. In this work we use Density Functional Theory and Transition State Theory including tunnelling corrections, reaction path degeneracy, the effect of diffusion, and the role of free radicals to get further insights into this important topic. The reaction between a leucine derivative and free radicals of biological significance, in aqueous and lipid media, has been investigated. Both thermochemical and kinetic analyses, in both hydrophilic and hydrophobic environments, have been carried out. DPPH, ˙OOH, ˙OOCH3, ˙OOCH2Cl, ˙OOCHCl2 and ˙OOCHCH2 radicals do not react with the target molecule. The reactions are proposed to be kinetically controlled. The leucine gamma site was the most reactive for the reactions with ˙N3, ˙OOCCl3, ˙OCH3, ˙OCH2Cl, and ˙OCHCl2 radicals, with rate constants equal to 1.97 × 10(5), 3.24 × 10(4), 6.68 × 10(5), 5.98 × 10(6) and 8.87 × 10(8) M(-1) s(-1), respectively, in aqueous solution. The ˙Cl, ˙OH and ˙OCCl3 radicals react with leucine at the beta, gamma, and delta positions at rates close to the diffusion limit with the alpha position which is the slowest path and the most thermodynamically favored. The presented results confirm that the Bell-Evans-Polanyi principle does not apply for the reactions between amino acid residues and free radicals. Regarding the influence of the environment on the reactivity of the studied series of free radicals towards leucine residues, it is concluded that hydrophilic media slightly lower the reactivity of the studied radicals, compared to hydrophobic ones, albeit the trends in reactivity are very similar.

  6. Non-invasive evaluation of voiding function in asymptomatic primary school children.

    Science.gov (United States)

    Dogan, Hasan Serkan; Akpinar, Burcu; Gurocak, Serhat; Akata, Deniz; Bakkaloglu, Mehmet; Tekgul, Serdar

    2008-07-01

    This study aimed to evaluate the voiding characteristics of primary school children by using questionnaires and non-invasive diagnostic tools. The voiding characteristics of 212 healthy children in two primary schools were evaluated with ultrasound for bladder wall thickness (BWT) in association with the Pediatric Lower Urinary Tract Symptom Score (PLUTSS), familial questionnaire, uroflowmetry (UF) and urinalysis. Most of the children (70%) had achieved urinary and fecal continence between the ages of 18 months and 36 months. Twenty-five per cent of healthy children void fewer than four times or more than seven times per day. Ninety percent of children had a PLUTSS within normal ranges (< 9). Fifteen percent of patients had a uroflowmetric pattern other than bell-shaped. The peak and average flow rates were higher in girls. Enuresis nocturna was detected in 10% of children. None of the children had documented urinary tract infection. The average BWT from posterior wall at full bladder in healthy children was 1.1 mm. The anterior and posterior BWT measurements before and after micturition were found to be thicker in boys. Regarding the UF pattern, in post-voiding measurements in children with abnormal UF pattern, the bladder walls were thicker. Non-invasive tests in non-symptomatic children showed a range of variability, and these deviations should be kept in mind during the evaluation of voiding characteristics of a child. The symptom scoring system, with the high sensitivity and specificity rates it possesses, is one of the promising tools for this purpose.

  7. Postural Hypo-Reactivity in Autism Is Contingent on Development and Visual Environment: A Fully Immersive Virtual Reality Study

    Science.gov (United States)

    Greffou, Selma; Bertone, Armando; Hahler, Eva-Maria; Hanssens, Jean-Marie; Mottron, Laurent; Faubert, Jocelyn

    2012-01-01

    Although atypical motor behaviors have been associated with autism, investigations regarding their possible origins are scarce. This study assessed the visual and vestibular components involved in atypical postural reactivity in autism. Postural reactivity and stability were measured for younger (12-15 years) and older (16-33 years) autistic…

  8. Effectiveness of reactive case detection for malaria elimination in three archetypical transmission settings: a modelling study.

    Science.gov (United States)

    Gerardin, Jaline; Bever, Caitlin A; Bridenbecker, Daniel; Hamainza, Busiku; Silumbe, Kafula; Miller, John M; Eisele, Thomas P; Eckhoff, Philip A; Wenger, Edward A

    2017-06-12

    Reactive case detection could be a powerful tool in malaria elimination, as it selectively targets transmission pockets. However, field operations have yet to demonstrate under which conditions, if any, reactive case detection is best poised to push a region to elimination. This study uses mathematical modelling to assess how baseline transmission intensity and local interconnectedness affect the impact of reactive activities in the context of other possible intervention packages. Communities in Southern Province, Zambia, where elimination operations are currently underway, were used as representatives of three archetypes of malaria transmission: low-transmission, high household density; high-transmission, low household density; and high-transmission, high household density. Transmission at the spatially-connected household level was simulated with a dynamical model of malaria transmission, and local variation in vectorial capacity and intervention coverage were parameterized according to data collected from the area. Various potential intervention packages were imposed on each of the archetypical settings and the resulting likelihoods of elimination by the end of 2020 were compared. Simulations predict that success of elimination campaigns in both low- and high-transmission areas is strongly dependent on stemming the flow of imported infections, underscoring the need for regional-scale strategies capable of reducing transmission concurrently across many connected areas. In historically low-transmission areas, treatment of clinical malaria should form the cornerstone of elimination operations, as most malaria infections in these areas are symptomatic and onward transmission would be mitigated through health system strengthening; reactive case detection has minimal impact in these settings. In historically high-transmission areas, vector control and case management are crucial for limiting outbreak size, and the asymptomatic reservoir must be addressed through

  9. Does stress reactivity or response to amphetamine predict smoking progression in young adults? A preliminary study.

    Science.gov (United States)

    de Wit, Harriet; Vicini, Lisa; Childs, Emma; Sayla, Maliha A; Terner, Jolan

    2007-02-01

    Recent studies with laboratory animals indicate that a constellation of behavioral factors predict progression to self-administer drugs. Relatively little is known about behavioral or biological factors that predict the progression in drug use from initial experimentation to regular use in human drug users. The present exploratory study examined reactivity to an acute stressor and reactivity to a single dose of a dopaminergic drug as predictors in progression to heavier smoking in young cigarette smokers over a 6-month period. Forty-four college students who were light to moderate smokers participated in three laboratory sessions, followed by a follow-up interview 6 months later to determine smoking level. On one of the laboratory sessions subjects underwent the Trier Social Stress Test, and on the others they ingested capsules containing placebo or 20 mg D-amphetamine. Outcome measures included subjective ratings of mood and measures of heart rate and salivary cortisol. We found modest positive relationships between stress reactivity and certain responses to amphetamine. Further, stress-induced increases in cortisol were positively related to increases in cigarette smoking in the 31 subjects who we were able to contact at 6 months. Although these results are highly preliminary, they resemble the relationships previously reported in laboratory animals, suggesting that some of the same factors that predict drug-self-administration in rodents predict progression in drug use among young adults.

  10. Dwarf Galaxies in the Nearby Lynx-Cancer Void: Photometry, Colours and Ages

    Science.gov (United States)

    Pustilnik, Simon; Kniazev, Alexei; Lyamina, Yulia; Tepliakova, Arina

    The nearby Lynx-Cancer void is a good laboratory to study the effect of very rarefied environment on the evolution of the least massive dwarf galaxies. A recently compiled sample of this void's galaxies includes about one hundred objects with MB in the range -12 to -18 mag. Good quality images are available in the SDSS database for ˜80% of the sample. Their u, g, r, i, z photometry allows one to derive galaxy stellar mass (and, incorporating HI data, gas mass-fraction) and ages of visible stellar populations, and hence, the epoch of their formation (first SF episode). We present the first photometric results of the ongoing study of the Lynx-Cancer void.

  11. Void lattice formation in electron irradiated CaF{sub 2}: Statistical analysis of experimental data and cellular automata simulations

    Energy Technology Data Exchange (ETDEWEB)

    Zvejnieks, G., E-mail: guntars@latnet.lv; Merzlyakov, P.; Kuzovkov, V.N.; Kotomin, E.A.

    2016-02-01

    Calcium fluoride (CaF{sub 2}) is an important optical material widely used in both microlithography and deep UV windows. It is known that under certain conditions electron beam irradiation can create therein a superlattice consisting of vacancy clusters (called a void lattice). The goal of this paper is twofold. Firstly, to perform a quantitative analysis of experimental TEM images demonstrating void lattice formation, we developed two distinct image filters. As a result, we can easily calculate vacancy concentration, vacancy cluster distribution function as well as average distances between defect clusters. The results for two suggested filters are similar and demonstrate that experimental void cluster growth is accompanied by a slight increase of the void lattice constant. Secondly, we proposed a microscopic model that allows us to reproduce a macroscopic void ordering, in agreement with experimental data, and to resolve existing theoretical and experimental contradictions. Our computer simulations demonstrate that macroscopic void lattice self-organization can occur only in a narrow parameter range. Moreover, we studied the kinetics of a void lattice ordering, starting from an initial disordered stage, in a good agreement with the TEM experimental data.

  12. Propagation of Love waves in a void medium over a sandy half space under gravity

    Science.gov (United States)

    Patra, Pulak; Gupta, Asit Kumar; Kundu, Santimoy

    2017-04-01

    The present study investigates the propagation of Love wave in a void layer resting over a sandy half space under the effect of gravitational force. The equations of motion have been gathered separately for different layers, and the boundary conditions have been introduced for two different layers at their interface. The mathematical analysis of the problem has been dealt with the help of Whittaker's function by expanding it asymptotically up to linear terms. The study reveals that in such a situation there exist two different wave fronts for the two above-mentioned layers: one is for the effects of gravity and sandy parameters, whereas other is for the effect of void parameter.

  13. Blunted cardiac reactivity to psychological stress associated with higher trait anxiety: a study in peacekeepers.

    Science.gov (United States)

    Souza, Gabriela Guerra Leal; Mendonça-de-Souza, Ana Carolina Ferraz; Duarte, Antônio Fernando Araújo; Fischer, Nastassja Lopes; Souza, Wanderson Fernandes; Coutinho, Evandro Silva Freire; Figueira, Ivan; Volchan, Eliane

    2015-11-23

    Both exaggerated and diminished reactivity to stress can be maladaptive. Previous studies have shown that performing increasingly difficult tasks leads first to increased reactivity and then to a blunted response when success is impossible. Our aim was to investigate the influence of trait anxiety on cardiac and cortisol response to and recovery from a standardized psychosocial stress task (Trier Social Stress Task) in a homogeneous sample of healthy peacekeepers. We hypothesized that participants with higher trait anxiety would show blunted reactivity during the performance of an overwhelmingly difficult and stressful task. Participants (N = 50) delivered a speech and performed an arithmetic task in the presence of critical evaluators. Cortisol samples and electrocardiogram data were collected. Participants completed the State-Trait Anxiety Inventory-Trait version, the Posttraumatic Stress Disorder Checklist-Civilian Version (PCL-C) and the Military Peace Force Stressor Inventory. For heart rate, the findings showed that peacekeepers with higher trait anxiety reacted less to the speech task (p = 0.03) and to the arithmetic task (p = 0.008) than those with lower trait anxiety. Trait anxiety did not modulate cortisol responses to the task. Despite the high trait anxiety group having higher PCL-C scores than the low trait anxiety group (p anxiety had less tachycardia in response to acute psychological stress than those with lower trait anxiety. The present results point to a higher risk for more anxious individuals of a maladaptive reaction to stressful events.

  14. Experimental study of low amplitude, long-duration mechanical loading of reactive materials

    Energy Technology Data Exchange (ETDEWEB)

    Urtiew, P A; Forbes, J W

    2000-10-03

    Studies of the low amplitude, long-duration mechanical loading of reactive materials rely very heavily on the experimental data in general and in particular on the data obtained from gauges placed within the experimental test sample to measure accurately the local changes of parameters of the investigated material. For a complete description of these changes taking place in a dynamically loaded material one would like to know both the spatial and the temporal resolution of pressure, temperature, volume, wave and mass velocity. However, temperature and volume are not easily attainable. Therefore, most of the in-situ work is limited to measurements of pressure and both wave and mass velocities. Various types of these gauges will be discussed and their records will be illustrated. Some of these gauges have limitations but are better suited for particular applications than others. These aspects will also be discussed. Main limitation of most in-situ gauges is that they are built for one-dimensional application. However, some work is being done to develop two-dimensional gauges. This work will also be briefly discussed. While these experiments are necessary to validate theoretical models of the phenomenon, they can also provide sufficient amount of data to yield complete information on material characteristics such as its equation of state (EOS), its phase change under certain loads and its sensitivity to shock loading. Processing of these data to get important information on the behavior of both reactive and non-reactive materials will also be demonstrated.

  15. Reactivity of sensorimotor oscillations is altered in children with hemiplegic cerebral palsy: A magnetoencephalographic study.

    Science.gov (United States)

    Pihko, Elina; Nevalainen, Päivi; Vaalto, Selja; Laaksonen, Kristina; Mäenpää, Helena; Valanne, Leena; Lauronen, Leena

    2014-08-01

    Cerebral palsy (CP) is characterized by difficulty in control of movement and posture due to brain damage during early development. In addition, tactile discrimination deficits are prevalent in CP. To study the function of somatosensory and motor systems in CP, we compared the reactivity of sensorimotor cortical oscillations to median nerve stimulation in 12 hemiplegic CP children vs. 12 typically developing children using magnetoencephalography. We also determined the primary cortical somatosensory and motor representation areas of the affected hand in the CP children using somatosensory-evoked magnetic fields and navigated transcranial magnetic stimulation, respectively. We hypothesized that the reactivity of the sensorimotor oscillations in alpha (10 Hz) and beta (20 Hz) bands would be altered in CP and that the beta-band reactivity would depend on the individual pattern of motor representation. Accordingly, in children with CP, suppression and rebound of both oscillations after stimulation of the contralateral hand were smaller in the lesioned than intact hemisphere. Furthermore, in two of the three children with CP having ipsilateral motor representation, the beta- but not alpha-band modulations were absent in both hemispheres after affected hand stimulation suggesting abnormal sensorimotor network interactions in these individuals. The results are consistent with widespread alterations in information processing in the sensorimotor system and complement current understanding of sensorimotor network development after early brain insults. Precise knowledge of the functional sensorimotor network organization may be useful in tailoring individual rehabilitation for people with CP. Copyright © 2014 Wiley Periodicals, Inc.

  16. Electrocortical reactivity to social feedback in youth: A pilot study of the Island Getaway task

    Directory of Open Access Journals (Sweden)

    Autumn Kujawa

    2014-10-01

    Full Text Available Peer relationships become a major concern in adolescence, yet event-related potential (ERP measures of reactivity to social feedback in adolescence are limited. In this pilot study, we tested a novel task to elicit reactivity to social feedback in youth. Participants (10–15 years old; 57.9% male; N = 19 played a game that involved exchanging personal information with peers, voting to remove players from the game, and receiving rejection and acceptance feedback from peers. Results indicated that participants modified their voting behavior in response to peer feedback, and rejection feedback was associated with a negativity in the ERP wave compared to acceptance (i.e., the feedback negativity, FN. The FN predicted behavioral patterns, such that participants who showed greater neural reactivity to social feedback were less likely to reject co-players. Preliminary analyses suggest that the task may be a useful measure of individual differences: adolescents higher in social anxiety symptoms were less likely to reject peers and showed an enhanced FN to rejection vs. acceptance feedback, and higher depressive symptoms predicted an increased FN to rejection specifically. Results suggest that the FN elicited by social feedback may be a useful, economical neural measure of social processing across development and in clinical research.

  17. Voiding patterns in men evaluated by a questionnaire survey

    DEFF Research Database (Denmark)

    Sommer, P; Nielsen, K K; Bauer, T

    1990-01-01

    A questionnaire on obstructive and irritative voiding symptoms was sent to 572 men aged between 20 and 79 years, selected at random from the National Register; 337 questionnaires were completed. None of the responders had consulted a doctor because of voiding symptoms. There was a significant...

  18. STRESS CONCENTRATION DUE TO A SPHERICAL VOID UNDER HERTZIAN CONTACT

    Directory of Open Access Journals (Sweden)

    Stelian ALACI,

    2010-06-01

    Full Text Available The present paper presents the method of estimating the stress concentrator effect of a spherical void from an elastic half-space. An essential part consists in estimation of FEM error by finding the contact pressure from half-plane using an analytical method. Next, the stress concentrator effect of the same void, except for placed into elastic space, is found.

  19. Nonlinear theory of void formation in colloidal plasmas.

    Science.gov (United States)

    Avinash, K; Bhattacharjee, A; Hu, S

    2003-02-21

    A nonlinear time-dependent model for void formation in colloidal plasmas is proposed. For experimentally relevant initial conditions, the model describes the nonlinear evolution of a zero-frequency linear instability that grows rapidly in the nonlinear regime and subsequently saturates to form a void. A number of features of the model are consistent with experimental observations under laboratory and microgravity conditions.

  20. Old Stellar Populations of The VGS Void Galaxies

    NARCIS (Netherlands)

    Beygu, Burcu; Jarrett, Thomas; Jarrett, Tom; van de Weygaert, Rien; Kreckel, Kathryn; van der Hulst, Thijs; van Gorkom, Jacqueline

    Cosmic voids form an essential ingredient of the Cosmic Web and may harbour a systematically different population of galaxies. Largely unaffected by the complex processes modifying galaxies in high-density environments, the pristine and isolated void regions must hold important clues to the

  1. Voids and the Cosmic Web: cosmic depression & spatial complexity

    NARCIS (Netherlands)

    van de Weygaert, Rien; Shandarin, S.; Saar, E.; Einasto, J.

    2016-01-01

    Voids form a prominent aspect of the Megaparsec distribution of galaxies and matter. Not only do theyrepresent a key constituent of the Cosmic Web, they also are one of the cleanest probesand measures of global cosmological parameters. The shape and evolution of voids are highly sensitive tothe

  2. 21 CFR 1305.28 - Canceling and voiding electronic orders.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Canceling and voiding electronic orders. 1305.28 Section 1305.28 Food and Drugs DRUG ENFORCEMENT ADMINISTRATION, DEPARTMENT OF JUSTICE ORDERS FOR SCHEDULE I AND II CONTROLLED SUBSTANCES Electronic Orders § 1305.28 Canceling and voiding electronic orders...

  3. Calculated Grain Size-Dependent Vacancy Supersaturation and its Effect on Void Formation

    DEFF Research Database (Denmark)

    Singh, Bachu Narain; Foreman, A. J. E.

    1974-01-01

    In order to study the effect of grain size on void formation during high-energy electron irradiations, the steady-state point defect concentration and vacancy supersaturation profiles have been calculated for three-dimensional spherical grains up to three microns in size. In the calculations...... of vacancy supersaturation as a function of grain size, the effects of internal sink density and the dislocation preference for interstitial attraction have been included. The computations show that the level of vacancy supersaturation achieved in a grain decreases with decreasing grain size. The grain size...... dependence of the maximum vacancy supersaturation in the centre of the grains is found to be very similar to the grain size dependence of the maximum void number density and void volume swelling measured in the central regions of austenitic stainless steel grains. This agreement reinforces the interpretation...

  4. Evaluation and Comparison of Freeze-Thaw Tests and Air Void Analysis of Pervious Concrete

    DEFF Research Database (Denmark)

    Lund, Mia Schou Møller; Hansen, Kurt Kielsgaard; Kevern, John T.

    2016-01-01

    Pearl-Chain Bridge technology is an innovative precast arch bridge solution which uses pervious concrete as fill material. To ensure longevity of the bridge superstructure it is necessary that the per-vious concrete fill is designed to be freeze-thaw durable; however, no standards exist on how...... to eval-uate the freeze-thaw resistance of fresh or hardened pervious concrete and correspondingly what constitutes acceptable freeze-thaw durability. A greater understanding of the correlation between the freeze-thaw performance and the air void structure of pervious concrete is needed. In the present...... study six pervious concrete mixes were exposed to freeze-thaw testing, and their air void structure was analyzed using an automated linear-traverse method. It was found that there is a miscorrelation between these two test methods in their assumption of whether or not the large interconnected voids...

  5. Nonlocal effects on localization in a void-sheet

    DEFF Research Database (Denmark)

    Tvergaard, Viggo; Needleman, A.

    1997-01-01

    For a nonlocal damage model it is expected that the characteristic material length relates to the damage mechanism. In the case of ductile fracture the most relevant length scales would be the average void radius or spacing. Cell model computations representing a single row of Voids in an infinite...... solid under plane strain conditions are here used to compare with predictions of a nonlocal Version of a porous ductile material model. Both the critical strain for the onset of plastic flow localization and the slope of the stress-strain curve in the post-localization range are compared...... the material characteristic length scales with the void radius, whereas for transversely aligned voids the scaling is with the void spacing. (C) 1997 Elsevier Science Ltd....

  6. Sensitivity effects of void density and arrangements in a REBO high explosive

    Energy Technology Data Exchange (ETDEWEB)

    Herring, Stuart Davis [Los Alamos National Laboratory; Germann, Timothy C [Los Alamos National Laboratory; Gronbech - Jensen, Niels [Los Alamos National Laboratory

    2010-09-28

    The shock response of two-dimensional model, high explosive crystals with various arrangements of circular voids is explored. We simulate a piston impact using molecular dynamics simulations with a Reactive Empirical Bond Order (REBO) model potential for a sub-micron, sub-ns exothermic reaction in a diatomic molecular solid. In square lattices of voids all of one size, reducing that size or increasing the porosity while holding the other parameter fixed causes the hotspots to consume the material more quickly and detonation to occur sooner and at lower piston velocities. The early time behavior is seen to follow a very simple ignition and growth model. The hotspots are seen to collectively develop a broad pressure wave (a sonic, diffuse deflagration front) that, upon merging with the lead shock, transforms it into a detonation. The reaction yields produced by triangular lattices are not significantly different. With random void arrangements, the mean time to detonation is 15.5% larger than with the square lattice; the standard deviation of detonation delays is just 5.1%.

  7. Ghrelin-reactive immunoglobulins and anxiety, depression and stress-induced cortisol response in adolescents. The TRAILS study.

    Science.gov (United States)

    François, Marie; Schaefer, Johanna M; Bole-Feysot, Christine; Déchelotte, Pierre; Verhulst, Frank C; Fetissov, Sergueï O

    2015-06-03

    Ghrelin, a hunger hormone, has been implicated in the regulation of stress-response, anxiety and depression. Ghrelin-reactive immunoglobulins (Ig) were recently identified in healthy and obese humans showing abilities to increase ghrelin's stability and orexigenic effects. Here we studied if ghrelin-reactive Ig are associated with anxiety and depression and with the stress-induced cortisol response in a general population of adolescents. Furthermore, to test the possible infectious origin of ghrelin-reactive Ig, their levels were compared with serum IgG against common viruses. We measured ghrelin-reactive IgM, IgG and IgA in serum samples of 1199 adolescents from the Dutch TRAILS study and tested their associations with 1) anxiety and depression symptoms assessed with the Youth Self-Report, 2) stress-induced salivary cortisol levels and 3) IgG against human herpesvirus 1, 2, 4 and 6 and Influenza A and B viruses. Ghrelin-reactive IgM and IgG correlated positively with levels of antibodies against Influenza A virus. Ghrelin-reactive IgM correlated negatively with antibodies against Influenza B virus. Ghrelin-reactive IgM correlated positively with anxiety scores in girls and ghrelin-reactive IgG correlated with stress-induced cortisol secretion, but these associations were weak and not significant after correction for multiple testing. These data indicate that production of ghrelin-reactive autoantibodies could be influenced by viral infections. Serum levels of ghrelin-reactive autoantibodies probably do not play a role in regulating anxiety, depression and the stress-response in adolescents from the general population. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Experimental and Theoretical Studies of the Reactivity and Thermochemistry of Dicyanamide: N(CN)(2)(-).

    Science.gov (United States)

    Nichols, Charles M; Wang, Zhe-Chen; Yang, Zhibo; Lineberger, W Carl; Bierbaum, Veronica M

    2016-02-25

    Dicyanamide [N(CN)2(-)] is a common anionic component of ionic liquids, several of which have shown hypergolic reactivity upon mixing with white-fuming nitric acid. In this study, we explore the thermochemistry of dicyanamide and its reactivity with nitric acid and other molecules to gain insight into the initial stages of the hypergolic phenomenon. We have developed and utilized an electrospray ion source for our selected ion flow tube (SIFT) to generate the dicyanamide anion. We have explored the general reactivity of this ion with several neutral molecules and atoms. Dicyanamide does not show reactivity with O2, H2SO4, H2O2, DBr, HCl, NH3, N2O, SO2, COS, CO2, CH3OH, H2O, CH4, N2, CF4, or SF6 (k < 1 × 10(-12) cm(3)/s); moreover, dicyanamide does not react with N atom, O atom, or electronically excited molecular oxygen (k < 5 × 10(-12) cm(3)/s), and our previous studies showed no reactivity with H atom. However, at 0.45 Torr helium, we observe the adduct of dicyanamide with nitric acid with an effective bimolecular rate constant of 2.7 × 10(-10) cm(3)/s. Intrinsically, dicyanamide is a very stable anion in the gas phase, as illustrated by its lack of reactivity, high electron-binding energy, and low proton affinity. The lack of reactivity of dicyanamide with H2SO4 gives an upper limit for the gas-phase deprotonation enthalpy of the parent compound (HNCNCN; <310 ± 3 kcal/mol). This limit is in agreement with theoretical calculations at the MP2/6-311++G(d,p) level of theory, finding that ΔH298 K(HNCNCN) = 308.5 kcal/mol. Dicyanamide has two different proton acceptor sites. Experimental and computational results indicate that it is lower in energy to protonate the terminal nitrile nitrogen than the central nitrogen. Although proton transfer to dicyanamide was not observed for any of the acidic molecules investigated here, the calculations on dicyanamide with one to three nitric acid molecules reveal that higher-order solvation can favor exothermic proton

  9. Study on Optimization Strategy for Voltage and Reactive Power Control of Wind Farm

    Science.gov (United States)

    Lu, Q.; Shi, L.; Chen, N.

    A method for calculating reactive power limit of wind farm comprised of doubly-fed induction generators (DFIG) is proposed. The reactive power limit of wind farm is the sum of reactive power limit of DFIGs which is calculated by the method considering static stability margin. Based on this, reactive power control of wind farm is discussed and proposed. The proposed reactive power control is divided into different control modes according to power factor of high voltage side in wind farm substation and voltage of low voltage side in point of interconnection(POI). In different control modes, different control objects are applied on reactive power regulation. After reactive power regulation is finished, some reactive power of wind farm should be released. At last, numerical test system is established, the result shows that the proposed method is effective to support voltage of POI

  10. Void Volume Swelling Dependent on Grain Size in Austenitic Stainless Steel

    DEFF Research Database (Denmark)

    Singh, Bachu Narain

    1973-01-01

    Describes some of the main findings of a systematic study of the effect of grain size on the void volume swelling. In this study a powder-produced 20 Ni/20 Cr austenitic stainless steel, with 0.02% carbon and without carbide-forming elements was used. Some specimens containing dispersions...

  11. Filling the voids in the SRTM elevation model — A TIN-based delta surface approach

    Science.gov (United States)

    Luedeling, Eike; Siebert, Stefan; Buerkert, Andreas

    The Digital Elevation Model (DEM) derived from NASA's Shuttle Radar Topography Mission is the most accurate near-global elevation model that is publicly available. However, it contains many data voids, mostly in mountainous terrain. This problem is particularly severe in the rugged Oman Mountains. This study presents a method to fill these voids using a fill surface derived from Russian military maps. For this we developed a new method, which is based on Triangular Irregular Networks (TINs). For each void, we extracted points around the edge of the void from the SRTM DEM and the fill surface. TINs were calculated from these points and converted to a base surface for each dataset. The fill base surface was subtracted from the fill surface, and the result added to the SRTM base surface. The fill surface could then seamlessly be merged with the SRTM DEM. For validation, we compared the resulting DEM to the original SRTM surface, to the fill DEM and to a surface calculated by the International Center for Tropical Agriculture (CIAT) from the SRTM data. We calculated the differences between measured GPS positions and the respective surfaces for 187,500 points throughout the mountain range (ΔGPS). Comparison of the means and standard deviations of these values showed that for the void areas, the fill surface was most accurate, with a standard deviation of the ΔGPS from the mean ΔGPS of 69 m, and only little accuracy was lost by merging it to the SRTM surface (standard deviation of 76 m). The CIAT model was much less accurate in these areas (standard deviation of 128 m). The results show that our method is capable of transferring the relative vertical accuracy of a fill surface to the void areas in the SRTM model, without introducing uncertainties about the absolute elevation of the fill surface. It is well suited for datasets with varying altitude biases, which is a common problem of older topographic information.

  12. Diffusion in and around alginate and chitosan films with embedded sub-millimeter voids

    Energy Technology Data Exchange (ETDEWEB)

    Patra, Subhajit; Bal, Dharmendra Kumar; Ganguly, Somenath, E-mail: snganguly@che.iitkgp.ernet.in

    2016-02-01

    Hydrogel scaffolds from biopolymers have potential use in the controlled release of drugs, and as 3-D structure for the formation of tissue matrix. This article describes the solute release behavior of alginate and chitosan films with embedded voids of sub-millimeter dimensions. Nitrogen gas was bubbled in a fluidic arrangement to generate bubbles, prior to the crosslinking. The crosslinked gel was dried in a vacuum oven, and subsequently, soaked in Vitamin B-12 solution. The dimensions of the voids immediately after the cross-linking of gel, and also after complete drying were obtained using a digital microscope and scanning electron microscope respectively. The porosity of the gel was measured gravimetrically. The release of Vitamin B-12 in PBS buffer on a shaker was studied. The release experiments were repeated at an elevated temperature of 37 °C in the presence of lysozyme. The diffusion coefficient within the gel layer and the mass transfer coefficient at the interface with the bulk-liquid were estimated using a mathematical model. For comparison, the experiment was repeated with a film that does not have any embedded void. The enhancement in diffusion coefficient due to the presence of voids is discussed in this article. - Highlights: • Formation of sub-millimeter voids in biopolymer films using fluidic arrangement • The retention of self-assembled bubbles in films after crosslinking, and drying • The enhancement observed in release of model drug with introduction of voids • The diffusion coefficients in and around biopolymer films from model regression • Use of classical model in explaining release profiles from dual porosity media.

  13. Taylor-plasticity-based analysis of length scale effects in void growth

    KAUST Repository

    Liu, Junxian

    2014-09-25

    We have studied the void growth problem by employing the Taylor-based strain gradient plasticity theories, from which we have chosen the following three, namely, the mechanism-based strain gradient (MSG) plasticity (Gao et al 1999 J. Mech. Phys. Solids 47 1239, Huang et al 2000 J. Mech. Phys. Solids 48 99-128), the Taylor-based nonlocal theory (TNT; 2001 Gao and Huang 2001 Int. J. Solids Struct. 38 2615) and the conventional theory of MSG (CMSG; Huang et al 2004 Int. J. Plast. 20 753). We have addressed the following three issues which occur when plastic deformation at the void surface is unconstrained. (1) Effects of elastic deformation. Elasticity is essential for cavitation instability. It is therefore important to guarantee that the gradient term entering the Taylor model is the effective plastic strain gradient instead of the total strain gradient. We propose a simple elastic-plastic decomposition method. When the void size approaches the minimum allowable initial void size related to the maximum allowable geometrically necessary dislocation density, overestimation of the flow stress due to the negligence of the elastic strain gradient is on the order of lεY/R0 near the void surface, where l, εY and R0 are, respectively, the intrinsic material length scale, the yield strain and the initial void radius. (2) MSG intrinsic inconsistency, which was initially mentioned in Gao et al (1999 J. Mech. Phys. Solids 47 1239) but has not been the topic of follow-up studies. We realize that MSG higher-order stress arises due to the linear-strain-field approximation within the mesoscale cell with a nonzero size, lε. Simple analysis shows that within an MSG mesoscale cell near the void surface, the difference between microscale and mesoscale strains is on the order of (lε/R0)2, indicating that when lε/R0 ∼ 1.0, the higher-order stress effect can make the MSG result considerably different from the TNT or CMSG results. (3) Critical condition for cavitation instability

  14. Urinary bladder rupture during voiding cystourethrography

    Directory of Open Access Journals (Sweden)

    Kyong Ok Lee

    2012-05-01

    Full Text Available Voiding cystourethrography (VCUG is a commonly performed diagnostic procedure for the evaluation of vesicoureteral reflux with urinary tract infection or congenital renal diseases in children. The procedure is relatively simple and cost-effective, and complications are very rare. The iatrogenic complication of VCUG range from discomfort, urinary tract infection to bacteremia, as well as bladder rupture. Bladder rupture is a rare complication of VCUG, and only a few cases were reported. Bladder rupture among healthy children during VCUG is an especially uncommon event. Bladder rupture associated with VCUG is usually more common in chronically unused bladders like chronic renal failure. Presented is a case of bladder rupture that occurred during a VCUG in a healthy 9-monthold infant, due to instilled action of dye by high pressure. This injury completely healed after 7 days of operation, and it was confirmed with a postoperative cystography. The patient’s bladder volume, underlying disease, velocity of the contrast media instilled, catheter size, and styles of instillation are important factors to prevent bladder rupture during VCUG. Management of bladder rupture should be individualized, but the majority of infants are treated with the operation. In conclusion, bladder rupture is a rare complication, however, delicate attention is needed in order to prevent more dire situations.

  15. Differentiating Challenge Reactivity from Psychomotor Activity in Studies of Children's Psychophysiology: Considerations for Theory and Measurement

    Science.gov (United States)

    Bush, Nicole R.; Alkon, Abbey; Obradovic, Jelena; Stamperdahl, Juliet; Boyce, W. Thomas

    2011-01-01

    Current methods of assessing children's physiological "stress reactivity" may be confounded by psychomotor activity, biasing estimates of the relation between reactivity and health. We examined the joint and independent contributions of psychomotor activity and challenge reactivity during a protocol for 5- and 6-year-old children (N = 338).…

  16. Dynamic void distribution in myoglobin and five mutants

    Science.gov (United States)

    Jiang, Yingying; Kirmizialtin, Serdal; Sanchez, Isaac C.

    2014-02-01

    Globular proteins contain cavities/voids that play specific roles in controlling protein function. Elongated cavities provide migration channels for the transport of ions and small molecules to the active center of a protein or enzyme. Using Monte Carlo and Molecular Dynamics on fully atomistic protein/water models, a new computational methodology is introduced that takes into account the protein's dynamic structure and maps all the cavities in and on the surface. To demonstrate its utility, the methodology is applied to study cavity structure in myoglobin and five of its mutants. Computed cavity and channel size distributions reveal significant differences relative to the wild type myoglobin. Computer visualization of the channels leading to the heme center indicates restricted ligand access for the mutants consistent with the existing interpretations. The new methodology provides a quantitative measure of cavity structure and distributions and can become a valuable tool for the structural characterization of proteins.

  17. Changes in skin test reactivity among adults with atopic disease: a 3-year prospective study

    DEFF Research Database (Denmark)

    Aslund, N.; Thomsen, S.F.; Molgaard, E.

    2008-01-01

    Background: Our knowledge about longtudinal predictors of atopy is limited. Objectives: To describe changes in skin test reactivity during a 3-year period in a sample of adolescents and adults with atopic disease and to identify factors of importance for these changes. Methods: From a sample of 1......, 186 candidates, ranging in age from 14 to 44 years, who in a screening questionnaire reported symptoms suggestive of respiratory allergic disease, 344 individuals with a positive skin prick test (SPT) result concomitantly with asthma and/or rhinitis were clinically studied on 2 occasions, 3 years...

  18. The effects of technological voids on the hydro-mechanical behaviour of compacted bentonite-sand mixture

    OpenAIRE

    Wang, Qiong; Minh Tang, Anh; Cui, Yu-Jun; Delage, Pierre; Barnichon, Jean-Dominique; Ye, Wei-min

    2013-01-01

    International audience; Compacted bentonite-based materials are often used as buffer materials in radioactive waste disposal. A good understanding of their hydro-mechanical behaviour is essential to ensure the disposal safety. In this study, a mixture of MX80 bentonite and sand was characterized in the laboratory in terms of water retention property, swelling pressure, compressibility and hydraulic conductivity. The effects of the technological voids or the voids inside the soil were investig...

  19. ESTUDIO DE REACTIVO INHIBIDOR - COLECTOR PARA MINERALES DE COBRE/STUDY OF REACTIVE COLLECTOR - INHIBITOR FOR COPPER MINERAL

    National Research Council Canada - National Science Library

    L Valderrama; Z Petkovic; I Rajevic

    2016-01-01

    STUDY OF REACTIVE COLLECTOR - INHIBITOR FOR COPPER MINERAL ABSTRACT In recent years the high costs in grinding have focused the attention on increasing efficiency and reducing consumption of grinding media...

  20. C-reactive protein and the risk of cancer: a mendelian randomization study

    DEFF Research Database (Denmark)

    Allin, Kristine H; Nordestgaard, Børge G; Zacho, Jeppe

    2010-01-01

    Elevated plasma levels of C-reactive protein (CRP), a marker of inflammation, are associated with an increased risk of cancer, but it is unclear whether this association is causal. We examined whether four common single-nucleotide polymorphisms (SNPs) in the CRP gene that are associated with alte......Elevated plasma levels of C-reactive protein (CRP), a marker of inflammation, are associated with an increased risk of cancer, but it is unclear whether this association is causal. We examined whether four common single-nucleotide polymorphisms (SNPs) in the CRP gene that are associated...... with altered plasma CRP levels are causally associated with an increased risk of cancer. The study population included participants in a prospective study (n = 10 215) and a cross-sectional study (n = 36 403) of the adult general population in Denmark, all of whom were genotyped for the CRP SNPs....... The association between plasma CRP levels measured by a high-sensitivity turbidimetry assay and the risk of cancer was examined for 8224 participants in the prospective study. The hazard ratio of cancer for a doubling of the plasma CRP level was 1.09 (95% confidence interval [CI] = 1.03 to 1.14). The nine most...

  1. Sensory organisation and reactive balance control of amateur rugby players: A cross-sectional study.

    Science.gov (United States)

    Chow, Gary C C; Chung, Joanne W Y; Ma, Ada W W; Macfarlane, Duncan J; Fong, Shirley S M

    2017-05-01

    This study compared the sensory organisation and reactive balance control of amateur rugby players and a control group. Forty-one amateur rugby players (22 males: 19 females; mean height ± SD = 168.8 ± 8.8 cm; mean weight ± SD = 63.9 ± 12.5 kg) and 31 control participants (22 males: 9 females; mean height ± SD = 171.5 ± 10.3 cm; mean weight ± SD = 63.8 ± 10.3 kg) completed the study. Their sensory organisation and standing balance performance were evaluated using a sensory organisation test (SOT), and their reactive balance performance was quantified using a motor control test (MCT). The SOT equilibrium scores (ES) and sensory ratios and the MCT motor response latencies were the major outcome measures. The results revealed that compared to the controls, amateur rugby players had lower SOT ESs under different sensory environments (P rugby group (P = .005, [Formula: see text] = 0.107 and 0.108, respectively). No significant difference was found in the somatosensory ratio (P = .853, [Formula: see text] rugby players demonstrated inferior standing balance performance compared to their non-trained counterparts. They relied less heavily on vestibular and visual inputs to maintain standing balance under different sensory environments. In addition, they reacted more slowly to postural disturbance, reflecting their suboptimal reactive balance ability in standing.

  2. The association of age of toilet training and dysfunctional voiding

    Directory of Open Access Journals (Sweden)

    Hodges SJ

    2014-10-01

    Full Text Available Steve J Hodges, Kyle A Richards, Ilya Gorbachinsky, L Spencer KraneDepartment of Urology, Wake Forest University, Winston-Salem, NC, USAObjective: To determine whether age of toilet training is associated with dysfunctional voiding in children.Materials and methods: We compared patients referred to the urologic clinics for voiding dysfunction with age-matched controls without urinary complaints. Characteristics including age and reason for toilet training, method of training, and encopresis or constipation were compared between both groups.Results: Initiation of toilet training prior to 24 months and later than 36 months of age were associated with dysfunctional voiding. However, dysfunctional voiding due to late toilet training was also associated with constipation.Conclusion: Dysfunctional voiding may be due to delayed emptying of the bowel and bladder by children. The symptoms of dysfunctional voiding are more common when toilet training early, as immature children may be less likely to empty in a timely manner, or when training late due to (or in association with constipation.Keywords: voiding dysfunction, constipation

  3. Long-term safety and efficacy of single-tablet combinations of solifenacin and tamsulosin oral controlled absorption system in men with storage and voiding lower urinary tract symptoms: results from the NEPTUNE Study and NEPTUNE II open-label extension.

    Science.gov (United States)

    Drake, Marcus J; Chapple, Christopher; Sokol, Roman; Oelke, Matthias; Traudtner, Klaudia; Klaver, Monique; Drogendijk, Ted; Van Kerrebroeck, Philip

    2015-02-01

    Short-term trials have demonstrated the efficacy and safety of combination therapy using antimuscarinics and α-blockers in men with lower urinary tract symptoms (LUTS). The Study of Solifenacin Succinate and Tamsulosin Hydrochloride OCAS (oral controlled absorption system) in Males with Lower Urinary Tract Symptoms (NEPTUNE) II is the first long-term study using solifenacin (Soli) and the oral controlled absorption system formulation of tamsulosin (TOCAS). To evaluate long-term (up to 52 wk) safety and efficacy of flexible dosing of two fixed-dose combinations (FDC) of Soli plus TOCAS in men with moderate to severe storage symptoms and voiding symptoms. Patients with both storage and voiding LUTS, maximum urinary flow rate of 4.0-12.0 ml/s, prostate size Urinary retention occurred in 13 of 1208 (1.1%) patients receiving one or more FDCs in NEPTUNE and/or NEPTUNE II; 8 (0.7%) required catheterisation (acute urinary retention [AUR]). Reductions in total IPSS and TUFS during NEPTUNE were maintained for up to 52 wk of FDC treatment, with mean reductions of 9.0 (standard deviation [SD]: 5.7) and 10.1 (SD: 9.2), respectively, from baseline to end of treatment. Clinically relevant improvements were also observed for secondary efficacy end points. Long-term treatment with FDC Soli plus TOCAS was well tolerated and efficacious in men with storage and voiding LUTS, with a low incidence of AUR. Treatment with solifenacin plus tamsulosin in a fixed-dose combination tablet was well tolerated by men with lower urinary tract symptoms. Improvements in symptoms were achieved after 4 wk of treatment, with further improvements at week 16 maintained for up to 52 wk throughout the study. Copyright © 2014 European Association of Urology. Published by Elsevier B.V. All rights reserved.

  4. Reactivity of γ-Terpinene with NO3 radicals: experimental approach for kinetic and mechanistic study.

    Science.gov (United States)

    Fouqueau, Axel; Cirtog, Manuela; Le Quilleuc, Meryll; Cazaunau, Mathieu; Pangui, Edouard; Duncianu, Marius; Doussin, Jean-François; Picquet-Varrault, Bénédicte

    2017-04-01

    Biogenic Volatile Organic Compounds (BVOC) are highly emitted by vegetation and play a key role in atmospheric chemistry. They are very reactive with atmospheric oxidants (OH, NO3, ozone) and significantly contribute to the formation of Secondary Organic Aerosol (SOA) at the global scale [1]. In addition, night-time chemistry initiated by NO3 radicals leads to the formation of organic nitrates which behave as reservoirs for reactive nitrogen. However, the reactivity of NO3 radical with BVOCs other than isoprene and α- and β-pinene, remains poorly understood. Among the BVOCs, γ-Terpinene is one of the most emitted by vegetation[2]. Two kinetic works were previously published on γ-Terpinene [3] [4], but mechanistic has never been studied. Thus, the aim of this work is to study the reactivity of γ-Terpinene with NO3 by performing experiments in simulation chambers. Kinetic, mechanism and SOA yield will be investigated. For this purpose, two different simulation chambers have been used: - First one, consisting of a Pyrex reactor of 1 m3 [5] coupled to a long path in situ FTIR spectrometer and a Proton Transfer Reaction Time of Flight Mass Spectrometer (PTR-ToF-MS) in NO+ mode which was internally developed in LISA, to measure organic nitrates concentration. - Second one, the CESAM chamber (http://cesam.cnrs.fr) [6] is a 4.2 m3 stainless steel chamber which permits to conduct SOA experiments at different temperature and relative humidity. In situ FTIR and PTR-ToF-MS are used to measure gaseous concentrations, and a SMPS was used to characterize particulate phase. Kinetic and mechanistic results will be discussed and compared with the literature values. References [1] Brown S. S., Stutz J., Nighttime radical observations and chemistry. Chem. Soc. Rev. (2012) 41, 6405-6447 [2] Helmig D., Klinger L.F., et al., Biogenic volatile organic compound emissions (BVOCs) I. Identifications from three continental sites in the U.S. Chemosphere. (1999), Vol. 38, No. 9, pp. 2163

  5. Immunoglobulin E sensitization to cross-reactive carbohydrate determinants: epidemiological study of clinical relevance and role of alcohol consumption

    DEFF Research Database (Denmark)

    Linneberg, Allan; Fenger, Runa Vavia; Husemoen, Lise-Lotte

    2010-01-01

    The determinants and biologic significance of IgE-mediated sensitization to cross-reactive carbohydrate determinants (CCDs) are not entirely known. An association between alcohol consumption and CCD sensitization has been reported in studies from Spain and Portugal.......The determinants and biologic significance of IgE-mediated sensitization to cross-reactive carbohydrate determinants (CCDs) are not entirely known. An association between alcohol consumption and CCD sensitization has been reported in studies from Spain and Portugal....

  6. In-situ study of beneficial utilization of coal fly ash in reactive mine tailings.

    Science.gov (United States)

    Lee, Joon Kyu; Shang, Julie Q; Wang, Hongliu; Zhao, Cheng

    2014-03-15

    Oxidation of reactive mine tailings and subsequent generation of acid mine drainage (AMD) have been long recognized as the largest environmental concern for the mining industry. Laboratory studies on utilization of coal fly ash in management of reactive mine tailings have shown reducing water and oxygen infiltration into tailings matrix, thus preventing oxidation of sulphide minerals and acid generation. However, few data from field studies to evaluate the performance of co-placement of mine tailings and fly ash (CMF hereafter) are reported in the open literature. This paper documents the construction and instrumentation of three CMF systems on the Musselwhite mine located in Ontario, Canada and presents results of 3-year real time monitoring. The field data indicates that the CMFs reduced the ingress of water due to cementation generated by hydration of fly ash. It was also found that the electrical conductivity of leachate from CMFs decreased in the early stage of co-placement, compared to the control. With further study, the principle and approach demonstrated in this paper can be adopted as a sustainable technology in the mine tailings management. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Reducing Schoolchildren With Reactive Aggression Through Child, Parent, and Conjoint Parent-Child Group Interventions: A Longitudinal Outcome Effectiveness Study.

    Science.gov (United States)

    Fung, Annis Lai Chu

    2017-10-10

    This study was the first to evaluate the effectiveness of three different group interventions to reduce children's reactive aggression based on the social information processing (SIP) model. In the first stage of screening, 3,734 children of Grades 4-6 completed the Reactive-Proactive Aggression Questionnaire (RPQ) to assess their reactive and proactive aggression. Respondents with a total score of z ≥ 1 on the RPQ were shortlisted for the second stage of screening by qualitative interview. Interviews with 475 children were conducted to select those who showed reactive aggression featuring a hostile attributional bias. Finally, 126 children (97 males and 29 females) aged 8 to 14 (M = 9.71, SD = 1.23) were selected and randomly assigned to one of the three groups: a child group, a parent group, and a parent-child group. A significant Time × Intervention effect was found for general and reactive aggression. The parent-child group and child group showed a significant drop in general aggression and reactive aggression from posttest to 6-month follow-up, after controlling for baseline scores, sex, and age. However, the parent group showed no treatment effect: reactive aggression scores were significantly higher than those in the child group at 6-month follow-up. This study has provided strong evidence that children with reactive aggression need direct and specific treatment to reconstruct the steps of the SIP involving the selection and interpretation of cues. The intervention could help to prevent severe violent crimes at the later stage of a reactive aggressor. © 2017 Family Process Institute.

  8. Voids and porosities in class I micropreparations filled with various resin composites.

    NARCIS (Netherlands)

    Opdam, N.J.M.; Roeters, F.J.M.; Boer, T. de; Pesschier, D.; Bronkhorst, E.M.

    2003-01-01

    In this in vitro study, voids inside a minimal occlusal restoration using different consistencies of resin composite and various application techniques were investigated. One hundred and fifty-two simulated, minimally invasive preparations, including a prepared fissure and an excavated carious

  9. Noninvasive ultrasound assessment of maternal vascular reactivity during pregnancy: a longitudinal study.

    Science.gov (United States)

    Kinzler, Wendy L; Smulian, John C; Ananth, Cande V; Vintzileos, Anthony M

    2004-08-01

    To estimate the pattern of maternal vascular reactivity in normal and high-risk pregnancies using postocclusion brachial artery diameter. Prospective, longitudinal study of 44 low-risk singleton pregnancies and 28 high-risk pregnancies, defined as pregestational diabetes (n = 7), chronic hypertension (n = 4), twin gestation (n = 6), and a previous history of preeclampsia, fetal growth restriction, or vascular disease (n = 11). During each trimester, the brachial artery was ultrasonographically imaged above the antecubital crease. Brachial artery diameter was measured and then occluded for 5 minutes using an inflated blood pressure cuff. Changes in brachial artery diameter at 1 minute after occlusion were expressed as percent change from baseline and were compared across trimesters for both low-risk and high-risk groups, adjusting for potential confounders. Brachial artery diameters were increased after occlusion in every trimester for all groups. For low-risk women, the degree of postocclusion brachial artery dilatation was similar in the first and second trimesters, but was lower in the third trimester. In the first trimester, low-risk women had significantly greater brachial artery diameter increases at 1 minute compared with high-risk singleton pregnancies (19% compared with 12%; P pregnancies complicated by pregestational diabetes or chronic hypertension had significantly smaller 1-minute brachial artery diameter changes in the first trimester (7.0 +/- 0.5%, P vascular disease had responses similar to low-risk women. Maternal vascular reactivity as assessed by postocclusion brachial artery dilatation decreases in the third trimester in both low-risk and high-risk women. In addition, singleton pregnancies at high risk for preeclampsia display decreased brachial artery reactivity compared with low-risk women.

  10. A Mouse Model of Latent Tuberculosis Infection to Study Intervention Strategies to Prevent Reactivation.

    Directory of Open Access Journals (Sweden)

    Andreas Kupz

    Full Text Available Infection with Mycobacterium tuberculosis (Mtb is the leading cause of death in human immunodeficiency virus (HIV+ individuals, particularly in Sub-Saharan Africa. Management of this deadly co-infection is a significant global health challenge that is exacerbated by the lack of efficient vaccines against both Mtb and HIV, as well as the lack of reliable and robust animal models for Mtb/HIV co-infection. Here we describe a tractable and reproducible mouse model to study the reactivation dynamics of latent Mtb infection following the loss of CD4+ T cells as it occurs in HIV-co-infected individuals. Whereas intradermally (i.d. infected C57BL/6 mice contained Mtb within the local draining lymph nodes, depletion of CD4+ cells led to progressive systemic spread of the bacteria and induction of lung pathology. To interrogate whether reactivation of Mtb after CD4+ T cell depletion can be reversed, we employed interleukin (IL-2/anti-IL-2 complex-mediated cell boost approaches. Although populations of non-CD4 lymphocytes, such as CD8+ memory T cells, natural killer (NK cells and double-negative (DN T cells significantly expanded after IL-2/anti-IL-2 complex treatment, progressive development of bacteremia and pathologic lung alterations could not be prevented. These data suggest that the failure to reverse Mtb reactivation is likely not due to anergy of the expanded cell subsets and rather indicates a limited potential for IL-2-complex-based therapies in the management of Mtb/HIV co-infection.

  11. Association of multiple Lugol-voiding lesions with synchronous and metachronous esophageal squamous cell carcinoma in patients with head and neck cancer.

    Science.gov (United States)

    Muto, Manabu; Hironaka, Shuichi; Nakane, Mari; Boku, Narikazu; Ohtsu, Atsushi; Yoshida, Shigeaki

    2002-10-01

    Patients with squamous cell carcinoma of the head and neck have a high prevalence of second primary esophageal squamous cell carcinomas. This study assessed the risk of developing second primary esophageal squamous cell carcinomas in patients with squamous cell carcinoma of the head and neck based on multiplicity of Lugol-voiding lesions observed by chromoendoscopy and patient characteristics. Three hundred eighty-nine patients with newly diagnosed squamous cell carcinoma of the head and neck were divided into 4 groups: no Lugol-voiding lesions; several (Lugol-voiding lesions; many (>10) small Lugol-voiding lesions; and many irregularly shaped, multiform Lugol-voiding lesions. Relative risk for the development of synchronous second primary esophageal squamous cell carcinomas was investigated by using univariate and multivariate analysis. Metachronous second primary esophageal squamous cell carcinomas was also studied among 227 patients followed more than 1 year after initial examination. Fifty-four (14%) of the 389 patients were found to have synchronous second primary esophageal squamous cell carcinomas. In particular, 55% of the patients with many irregular-shaped multiform Lugol-voiding lesions had synchronous second primary esophageal squamous cell carcinomas. Univariate analysis showed that the presence of many irregular-shaped multiform Lugol-voiding lesions, drinking habit, male gender, and smoking were significant risk factors for the development of synchronous second primary esophageal squamous cell carcinomas. Multivariate analysis also revealed that many irregular-shaped multiform Lugol-voiding lesions (odds ratio: 21.4; p Lugol-voiding lesions and the seventh had many small Lugol-voiding lesions in the background mucosa. The presence of numerous irregular-shaped multiform Lugol-voiding lesions was closely associated with second primary esophageal squamous cell carcinomas in patients with squamous cell carcinoma of the head and neck. This might be

  12. Quantitative structure–reactivity study on sulfonation of amines, alcohols and phenols

    Directory of Open Access Journals (Sweden)

    Abolghasem Beheshti

    2017-05-01

    Full Text Available Quantitative structure–reactivity relationship (QSRR can be considered as a variant of quantitative structure property relationship (QSPR studies, where the chemical reactivity of reactants in a specified chemical reaction is related to chemical structure. As follows, the sulfonation reaction yield of 24 amines, alcohols and phenols with sulfonyl chloride was studied by QSRR. Quantum chemical calculations (b3lyp/6-31+g (d were carried out to obtain the optimized geometry. The suitable set of molecular descriptors was calculated to represent the molecular structures of compounds, such as constitutional, topological, geometrical, electrostatic and quantum-chemical descriptors. The genetic algorithm (GA was applied to select the variables that resulted in the best-fitted models. After the variable selection, multiple linear regression (MLR was utilized to construct linear QSRR models. The maximum relative error in prediction (5.26 showed that the predictive ability of the model was satisfactory and it can be used for designing similar reactants with efficient sulfonation reaction.

  13. Study on the NO{sub 3} radical reactivity: Reactions with cyclic alkenes

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, E.; Cabanas, B.; Aranda, A.; Martin, P.; Notario, A.; Salgado, S. [Univ. de Castilla-La Mancha, Ciudad Real (Spain). Facultad de Quimicas

    1999-07-08

    Much effort has been expended in studies of NO{sub 3} radical chemistry. The emphasis has been placed on investigating reaction rates and products of various organic and inorganic compounds to understand the behavior of this reactive radical in the atmosphere. The rate constants of the reactions of NO{sub 3} with cyclopentene, cyclohexene, cycloheptene, 1-methylcyclohexene, and methylenecyclohexane have been measured as a function of temperature at low pressure in a fast flow system with LiF detection of NO{sub 3}. The measured room temperature (298 K) rate constants for these reactions are given. The proposed Arrhenius expressions for the studied reactions are also given. The influence of substitution in the double bond and the ring size effect in unsubstituted cyclic monoalkenes has been investigated for the reactivity of the NO{sub 3} radical reactions. The rate coefficients and the activation energies for the reaction of the nitrate radical with methylenecyclohexane and 1-methylcyclohexene have also been compared with the corresponding values of some selected terpenes with similar structure to these compounds.

  14. On the Importance of Water Molecules in the Theoretical Study of Polyphenols Reactivity toward Superoxide Anion

    Directory of Open Access Journals (Sweden)

    Laure Lespade

    2014-01-01

    Full Text Available Numerous studies have shown the benefits of a diet rich in fruits and vegetables. These benefits are partly due to the radical scavenging properties of polyphenols contained in fruits and vegetables since polyphenols can fight against an excess of radicals which goes along inflammation in a certain number of diseases. This pathological state, called oxidative stress, results from the aerobic condition of human organism when OH radical, hydrogen peroxide, superoxide anion, or peroxynitrite is produced in excess. If hydrogen peroxide is easily handled by human defense against radicals, the other radicals can cause damage to biological constituents like lipids, cell membranes, and other biomolecules. This paper is devoted to the theoretical study of the interaction of superoxide anion (O2•- with a very potent radical scavenger, 1,2,4,6,8-pentahydroxynaphthalene. The importance of hydration of superoxide radical for the reactivity is analyzed. Potential energy surfaces (PES are calculated for different number of water molecules around the radical and it is shown that the transition barrier vanishes when complete hydration with six water molecules is explicitly handled. The nature of the reactivity is determined by using the natural bond orbital (NBO analysis.

  15. Mold elicits atopic dermatitis by reactive oxygen species: Epidemiology and mechanism studies.

    Science.gov (United States)

    Kim, Ha-Jung; Lee, Eun; Lee, Seung-Hwa; Kang, Mi-Jin; Hong, Soo-Jong

    2015-12-01

    Mold has been implicated in the development of atopic dermatitis (AD); however, the underlying mechanisms remain unknown. The aim of the study was to investigate the effects of mold exposure in early life through epidemiologic and mechanistic studies in vivo and in vitro. Exposure to visible mold inside the home during the first year of life was associated with an increased risk for current AD by two population-based cross-sectional human studies. Children with the AG+GG genotype of GSTP1 showed increased risk for current AD when exposed to mold. In the mouse model, treatment with patulin induced and aggravated clinically significant AD and Th2-related inflammation of the affected mouse skin. Additionally, reactive oxygen species (ROS) were released in the mouse skin as well by human keratinocytes. In conclusions, mold exposure increases the risk for AD related to ROS generation mediated by Th2-promoting inflammatory cytokines. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Electron Spin Resonance Spectroscopy for Studying the Generation and Scavenging of Reactive Oxygen Species by Nanomaterials

    Science.gov (United States)

    Yin, Jun-Jie; Zhao, Baozhong; Xia, Qingsu; Fu, Peter P.

    2013-09-01

    One fundamental mechanism widely described for nanotoxicity involves oxidative damage due to generation of free radicals and other reactive oxygen species. Indeed, the ability of nanoscale materials to facilitate the transfer of electrons, and thereby promote oxidative damage or in some instances provide antioxidant protection, may be a fundamental property of these materials. Any assessment of a nanoscale material's safety must therefore consider the potential for toxicity arising from oxidative damage. Therefore, rapid and predictive methods are needed to assess oxidative damage elicited by nanoscale materials. The use of electron spin resonance (ESR) to study free radical related bioactivity of nanomaterials has several advantages for free radical determination and identification. Specifically it can directly assess antioxidant quenching or prooxidant generation of relevant free radicals and reactive oxygen species. In this chapter, we have reported some nonclassical behaviors of the electron spin relaxation properties of unpaired electrons in different fullerenes and the investigation of anti/prooxidant activity by various types of nanomaterials using ESR. In addition, we have reviewed the mechanisms of free radical formation photosensitized by different nanomaterials. This chapter also included the use of spin labels, spin traps and ESR oximetry to systematically examine the enzymatic mimetic activities of nanomaterials.

  17. New quinolone derivative: Spectroscopic characterization and reactivity study by DFT and MD approaches

    Science.gov (United States)

    Ranjith, P. K.; Mary, Y. Sheena; Panicker, C. Yohannan; Anto, P. L.; Armaković, Stevan; Armaković, Sanja J.; Musiol, Robert; Jampilek, Josef; Van Alsenoy, C.

    2017-05-01

    The spectral characterization of ethyl-4-hydroxy-2-oxo-1, 2-dihydroquinoline-3-carboxylate (EHODQ3C) was performed by FT-IR and FT-Raman spectroscopic techniques and density functional theory computations have been carried using B3LYP/6-311++G(d,p) method. On the basis of potential energy distribution the vibrational assignments of the wavenumbers were proposed. Splitting of the Nsbnd H stretching mode and downshifted from the computed value which indicates the weakening of the Nsbnd H bond. NBO analysis was performed to study donor acceptor interactions. DFT calculations and molecular dynamics (MD) simulations have been combined in order to investigate fundamental reactive properties of the title molecule. To determine important reactive molecule sites we have calculated average local ionization energies (ALIE) and Fukui functions. Sensitivity towards autoxidation mechanism has been investigated by calculation of bond dissociation energies, while stability of title molecule in water has been investigated by calculation of radial distribution functions (RDF) after (MD) simulations. EHODQ3C exhibits inhibitory activity against ACP reductase and appears to be highly selective.

  18. Case study of the sonochemical decolouration of textile azo dye Reactive Black 5

    Energy Technology Data Exchange (ETDEWEB)

    Vajnhandl, Simona [University of Maribor, Faculty of Mechanical Engineering, Smetanova 17, 2000 Maribor (Slovenia)]. E-mail: simona.vajnhandl@uni-mb.si; Le Marechal, Alenka Majcen [University of Maribor, Faculty of Mechanical Engineering, Smetanova 17, 2000 Maribor (Slovenia)

    2007-03-06

    The decolouration and mineralization of reactive dye C.I. Reactive Black 5, a well-known representative of non-biodegradable azo dyes, by means of ultrasonic irradiation at 20, 279 and 817 kHz has been investigated with emphasis on the effect of various parameters on decolouration and degradation efficiency. Characterization of the used ultrasound systems was performed using calorimetric measurements and oxidative species monitoring using Fricke and iodine dosimeter. Experiments were carried out with low frequency probe type, and a high-frequency plate type transducer at 50, 100 and 150 W of acoustic power and within the 5-300 mg/L initial dye concentration range. Decolouration, as well as radical production, increased with increasing frequency, acoustic power, and irradiation time. Any increase in initial dye concentration results in decreased decolouration rates. Sonochemical decolouration was substantially depressed by the addition of 2-methyl-2-propanol as a radical scavenger, which suggests radical-induced reactions in the solution. Acute toxicity to marine bacteria Vibrio fischeri was tested before and after ultrasound irradiation. Under the conditions employed in this study, no toxic compounds were detected after 6 h of irradiation. Mineralization of the dye was followed by TOC measurements. Relatively low degradation efficiency (50% after 6 h of treatment) indicates that ultrasound is rather inefficient in overall degradation, when used alone.

  19. Experimental Study and Reactive Transport Modeling of Boric Acid Leaching of Concrete

    Directory of Open Access Journals (Sweden)

    Chiang K.-T. K.

    2013-07-01

    Full Text Available Borated water leakage through spent fuel pools (SFPs at pressurized water reactors is a concern because it could cause corrosion of reinforcement steel in the concrete structure, compromise the integrity of the structure, or cause unmonitored releases of contaminated water to the environment. Experimental data indicate that pH is a critical parameter that determines the corrosion susceptibility of rebar in borated water and the degree of concrete degradation by boric acid leaching. In this study, reactive transport modeling of concrete leaching by borated water was performed to provide information on the solution pH in the concrete crack or matrix and the degree of concrete degradation at different locations of an SFP concrete structure exposed to borated water. Simulations up to 100 years were performed using different boric acid concentrations, crack apertures, and solution flow rates. Concrete cylinders were immersed in boric acid solutions for several months and the mineralogical changes and boric acid penetration in the concrete cylinder were evaluated as a function of time. The depths of concrete leaching by boric acid solution derived from the reactive transport simulations were compared with the measured boric acid penetration depth.

  20. Void formation in ODS EUROFER produced by hot isostatic pressing

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, Y. [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain)], E-mail: yanicet@fis.ucm.es; Monge, M.A. [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain); Castro, V. de [Department of Materials, University of Oxford, Oxford OX1 3PH (United Kingdom); Munoz, A.; Leguey, T.; Pareja, R. [Departamento de Fisica, Universidad Carlos III de Madrid, 28911 Leganes (Spain)

    2009-04-30

    Positron annihilation experiments were performed on oxide dispersion strengthened (ODS) and non-ODS EUROFER prepared by mechanical alloying and hot isostatic pressing. The results revealed the presence of small voids in these materials in the as-HIPed conditions. Their evolution under isochronal annealing experiments was investigated. The coincidence Doppler broadening spectra of ODS EUROFER exhibited a characteristic signature attributed to positron annihilation in Ar-decorated voids at the oxide particle/matrix interfaces. The variation of the positron annihilation parameters with the annealing temperature showed three stages: up to 623 K, between 823 and 1323 K, and above 1323 K. In the temperature range 823-1323 K void coarsening had effect. Above 1323 K some voids annealed out, but others, associated to oxide particles and small precipitates, survived to annealing at 1523 K. Transmission electron microscopy observations were also performed to verify the characteristics of the surviving defects after annealing at 1523 K.

  1. Effects of Voids on Postbuckling Delamination Growth in Unidirectional Composites

    National Research Council Canada - National Science Library

    Zhuang, Linqi; Talreja, Ramesh

    .... In the finite element model developed, a through-width delamination is introduced close to one surface of a flat panel, and a void is placed in the delamination plane ahead of each delamination front...

  2. Mechanisms of void coarsening in helium implanted silicon

    CERN Document Server

    Evans, J H

    2002-01-01

    There has been recent discussion of the mechanisms that give rise to the observed coarsening of void populations introduced into silicon by implanting helium and then annealing to remove the helium. Over the temperature range from approximately 700 to 1000 degree sign C and beyond, further annealing leads to an increase of the average void size and decrease in void density. This paper sets out to calculate the coarsening expected from the two primary potential mechanisms, migration and coalescence (M and C) and Ostwald ripening (OR). The methodology of the calculations is carefully set out together with the surface diffusion and vacancy diffusion parameters on which the mechanisms depend. For moderate anneal temperatures, up to 1000 degree sign C, it would seem unlikely that OR can play any part in void coarsening. On the other hand, M and C calculations show that this mechanism gives results consistent with the size range found in experimental results.

  3. Sensitivity and uncertainty analysis of reactivities for UO2 and MOX fueled PWR cells

    Energy Technology Data Exchange (ETDEWEB)

    Foad, Basma [Research Institute of Nuclear Engineering, University of Fukui, Kanawa-cho 1-2-4, Tsuruga-shi, Fukui-ken, 914-0055 (Japan); Egypt Nuclear and Radiological Regulatory Authority, 3 Ahmad El Zomar St., Nasr City, Cairo, 11787 (Egypt); Takeda, Toshikazu [Research Institute of Nuclear Engineering, University of Fukui, Kanawa-cho 1-2-4, Tsuruga-shi, Fukui-ken, 914-0055 (Japan)

    2015-12-31

    The purpose of this paper is to apply our improved method for calculating sensitivities and uncertainties of reactivity responses for UO{sub 2} and MOX fueled pressurized water reactor cells. The improved method has been used to calculate sensitivity coefficients relative to infinite dilution cross-sections, where the self-shielding effect is taken into account. Two types of reactivities are considered: Doppler reactivity and coolant void reactivity, for each type of reactivity, the sensitivities are calculated for small and large perturbations. The results have demonstrated that the reactivity responses have larger relative uncertainty than eigenvalue responses. In addition, the uncertainty of coolant void reactivity is much greater than Doppler reactivity especially for large perturbations. The sensitivity coefficients and uncertainties of both reactivities were verified by comparing with SCALE code results using ENDF/B-VII library and good agreements have been found.

  4. Void Points, Rosettes, and a Brief History of Planetary Astronomy

    Science.gov (United States)

    Kosso, Peter

    2013-12-01

    Almost all models of planetary orbits, from Aristotle through Newton, include void points, empty points in space that have an essential role in defining the orbit. By highlighting the role of these void points, as well as the rosette pattern of the orbit that often results, I bring out different features in the history of planetary astronomy and place a different emphasis on its revolutionary changes, different from those rendered in terms of epicycles or the location of the earth.

  5. How the OH reactivity affects the ozone production efficiency: case studies in Beijing and Heshan, China

    Science.gov (United States)

    Yang, Yudong; Shao, Min; Keßel, Stephan; Li, Yue; Lu, Keding; Lu, Sihua; Williams, Jonathan; Zhang, Yuanhang; Zeng, Liming; Nölscher, Anke C.; Wu, Yusheng; Wang, Xuemei; Zheng, Junyu

    2017-06-01

    Total OH reactivity measurements were conducted on the Peking University campus (Beijing) in August 2013 and in Heshan (Guangdong province) from October to November 2014. The daily median OH reactivity was 20 ± 11 s-1 in Beijing and 31 ± 20 s-1 in Heshan, respectively. The data in Beijing showed a distinct diurnal pattern with the maxima over 27 s-1 in the early morning and minima below 16 s-1 in the afternoon. The diurnal pattern in Heshan was not as evident as in Beijing. Missing reactivity, defined as the difference between measured and calculated OH reactivity, was observed at both sites, with 21 % missing reactivity in Beijing and 32 % missing reactivity in Heshan. Unmeasured primary species, such as branched alkenes, could contribute to missing reactivity in Beijing, especially during morning rush hours. An observation-based model with the RACM2 (Regional Atmospheric Chemical Mechanism version 2) was used to understand the daytime missing reactivity in Beijing by adding unmeasured oxygenated volatile organic compounds and simulated intermediates of the degradation from primary volatile organic compounds (VOCs). However, the model could not find a convincing explanation for the missing reactivity in Heshan, where the ambient air was found to be more aged, and the missing reactivity was presumably attributed to oxidized species, such as unmeasured aldehydes, acids and dicarbonyls. The ozone production efficiency was 21 % higher in Beijing and 30 % higher in Heshan when the model was constrained by the measured reactivity, compared to the calculations with measured and modeled species included, indicating the importance of quantifying the OH reactivity for better understanding ozone chemistry.

  6. Reactivation of model cholinesterases by oximes and intermediate phosphyloximes: A computational study

    OpenAIRE

    Vyas, Shubham; Hadad, Christopher M.

    2008-01-01

    Phosphyloximes (POX) are generated upon the reactivation of organophosphorus (OP) inhibited cholinesterases (ChEs) by pyridinium oximes. These POXs are known to be potent inhibitors of the ChEs following reactivation. However, they can also decompose to give an OP derivative and a cyano derivative of the oxime when a base abstracts the benzylic proton. Using density functional theory, thermodynamic properties were calculated for the reactivation and decomposition pathways of three different o...

  7. C-reactive protein, insulin resistance and risk of cardiovascular disease: a population-based study

    DEFF Research Database (Denmark)

    Hansen, T.W.; Olsen, M.H.; Rasmussen, S.

    2008-01-01

    BACKGROUND: C-reactive protein (CRP), a marker of inflammation, and insulin resistance (IR), a metabolic disorder, are closely related. CRP and IR have both been identified as significant risk factors of cardiovascular disease (CVD) after adjustment for conventional CVD risk factors....... It is not clear whether CRP predicts CVD independent of IR. DESIGN: Prospective population-based study. METHODS: Two thousand three hundred and fifty-seven Danish men and women, recruited from the general population, aged 41-72 years, without major CVD at baseline were studied. Traditional and new risk factors...... were recorded at baseline. CRP was determined by a high-sensitivity assay, and IR was determined by the homoeostasis model assessment (HOMA-IR) method. RESULTS: Over a median follow-up of 9.4 years, the incidence of the prespecified CV event, defined as the composite event of CV death, nonfatal...

  8. ACK filling void first algorithm and performance for asynchronous OPS

    Science.gov (United States)

    Liu, Huanlin; Shi, Yonghe; Chen, Qianbin; Pan, Yingjun

    2007-11-01

    OPS with feedback shared FDL buffer produce large voids due to FDL buffers only supplying discrete step delay and causing FDL queue virtually occupation. By analyzing the TCP traffic and ACK packets feature, the ACK packet void filling first scheduling is presented to decrease packet loss rate and to reduce the FDL voids. When the FDL buffer void size is fit for the ACK packet, the ACK packet is scheduled to FDL immediately. An ACK and non-ACK packets difference and process flow is designed according the TCP packet frame structure. Compared with the conventional FIFO scheduling and smallest FDL void first scheduling, the algorithm reduces greatly the number of ACK occupying the FDL buffer and eliminates large numbers of ACK's bad influence on efficiency of IP data transmission under different FDL buffer depth and traffic load. The results of simulation show that the proposed scheduling makes use of ACK packets first void filling scheduling mechanism to reduce FDL excess load, increases output utilization and reduce packet loss ratio for asynchronous optical network. This approach is shown to minimize the FDL numbers with the feature of high stabilization and photonic integration and to improve real time TCP traffic performance for Internet network.

  9. VizieR Online Data Catalog: Galaxies in the Lynx-Cancer void (Pustilnik+, 2011)

    Science.gov (United States)

    Pustilnik, S. A.; Tepliakova, A. L.

    2012-02-01

    The evolution of galaxies is influenced by the environment in which they reside. This effect should be strongest for the lowest-mass and lowest-luminosity galaxies. To study dwarf galaxies in extremely low density environments, we have compiled a deep catalogue of dwarf galaxies in the nearby Lynx-Cancer void. This void hosts some of the most metal-poor dwarfs known to date. It borders the Local Volume at negative supergalactic Z(SGZ) coordinates and has a size of more than 16Mpc. With a distance to its centre of only 18Mpc, it is close enough to allow a search for the faintest dwarfs. Within the void 75 dwarf (-11.9>MB>-18.0) and four subluminous (-18.0>MB>-18.4) galaxies have been identified. We present the parameters of the void galaxies and a detailed analysis of the completeness of the catalogue as a function of magnitude and surface brightness. (3 data files).

  10. The effect of voide size on the detonation pressure of emulsion explosives.

    Science.gov (United States)

    Hirosaki, Yoshikazu; Murata, Kenji; Kato, Yukio; Itoh, Shigeru

    2001-06-01

    Ammonium nitrate-based emulsion explosive show non-ideal detonation behavior. Voids included in the emulsion explosives affect the non-idealdetonation behavior. The effects of voide size on the detonation pressure of emulsion explosives were studied experimentally. Detonation pressure was measured for the emulsion explosives sensitized with resin balloons of five different size ranging from 0.05mm to 2.42mm in average diameter, using PVDF pressure sensor. Pressure profile of emulsion explosives containing resin balloon of 0.05mm in average diamater shows von Neumann spike and pressure decay in reaction zone followed by Taylor wave. Pressure profile of emulsion explosive containing larger balloons present gradual pressure rise in detonation front due to front curvature and front perturvation caused by large voids. The comparison between the measured detonation pressure and calculated detonation pressure indicates that the fraction of ammonium nitrate reacted in reaction zone is higher than 80containing resin balloons of 0.05mm in diameter, and as low as 302.42mm in diameter. It was shown that reaction zone length is strongly affected by void size.

  11. Voiding school as a treatment of daytime incontinence or enuresis: Children's experiences of the intervention.

    Science.gov (United States)

    Saarikoski, A; Koppeli, R; Salanterä, S; Taskinen, S; Axelin, A

    2017-09-23

    Daytime incontinence and enuresis are common problems in otherwise healthy children, and negatively influence their social lives and self-esteem. Motivation for treatment is often a real clinical problem. Children's experiences of their incontinence treatments have not been previously described. The aim of this study was to describe children's experiences of the Voiding School intervention as a treatment for their incontinence. A qualitative, descriptive focus-group study with a purposive sample was conducted at a Finish university hospital in 2014. Children aged 6-12 years participated in the Voiding School at an outpatient clinic. The intervention included two 1-day group visits 2 months apart. The educational content was based on the International Children Continence Society's standards for urotherapy. The education was delivered with child-oriented teaching methods. At the end of the second visit, 19 children were interviewed in five groups. Data were analysed with inductive content analysis. The children described incontinence as an embarrassing problem, which they had to hide at any cost. They had experienced bullying and social isolation because of it. Normal outpatient visits emphasized adult-to-adult communication, which made the children feel like outsiders. The children perceived the Voiding School as a nice and child-oriented experience. Making new friends was especially important to younger boys who felt that the Voiding School day was too long and issue-oriented. In the Voiding School, videos and 'learning by doing' helped the children to understand the basis of given advice, and they were able to learn new habits, which gave them control over the incontinence; this helped them to become 'the boss of the bladder'. Sharing experiences and improvements in their incontinence with their peers supported the children's self-esteem and encouraged them to do new things, such as staying overnight with friends. These experiences helped them to acquire control

  12. Reactive arthritis in relation to internal derangements of the temporomandibular joint: a case control study.

    Science.gov (United States)

    Lund, Bodil; Holmlund, Anders; Wretlind, Bengt; Jalal, Shah; Rosén, Annika

    2015-09-01

    The aim of this study was to find out if reactive arthritis was involved in the aetiology of chronic closed lock of the temporomandibular joint (TMJ) by looking for bacterial antigens in the synovial membrane of the TMJ, and by studying the antibody serology and carriage of human leucocyte antigen (HLA) B27 in patients with chronic closed lock. Patients with reciprocal clicking and healthy subjects acted as controls. We studied a total of 43 consecutive patients, 15 with chronic closed lock, 13 with reciprocal clicking, and 15 healthy controls with no internal derangements of the TMJ. Venous blood samples were collected from all subjects for measurement of concentrations of HLA tissue antigen and serology against Chlamydia trachomatis, Yersinia enterocolitica, Salmonella spp., Campylobacter jejuni, and Mycoplasma pneumoniae. Samples of synovial tissue from patients with closed lock and reciprocal clicking were obtained during discectomy and divided into two pieces, the first of which was tested by strand displacement amplification for the presence of C trachomatis, and the second of which was analysed for the presence of species-specific bacterial DNA using 16s rRNA pan-polymerase chain reaction (PCR). There were no significant differences between the groups in the incidence of antibodies against M pneumoniae, Salmonella spp. or Y enterocolitica. No patient had antibodies towards C trachomatis or C jejuni. We found no bacterial DNA in the synovial fluid from any patient. The HLA B27 antigen was present in 2/15 subjects in both the closed lock and control groups, and none in the reciprocal clicking group. In conclusion, reactive arthritis does not seem to be the mechanism of internal derangement of the TMJ. Copyright © 2015. Published by Elsevier Ltd.

  13. DETECTION OF MOLECULAR GAS IN VOID GALAXIES: IMPLICATIONS FOR STAR FORMATION IN ISOLATED ENVIRONMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Das, M.; Honey, M. [Indian Institute of Astrophysics, Bangalore (India); Saito, T. [Department of Astronomy, Graduate school of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 133-0033 (Japan); Iono, D. [Chile Observatory, NAOJ (Japan); Ramya, S., E-mail: mousumi@iiap.res.in [Shanghai Astronomical Observatory, Shanghai (China)

    2015-12-10

    We present the detection of molecular gas from galaxies located in nearby voids using the CO(1–0) line emission as a tracer. The observations were performed using the 45 m single dish radio telescope of the Nobeyama Radio Observatory. Void galaxies lie in the most underdense parts of our universe and a significant fraction of them are gas rich, late-type spiral galaxies. Although isolated, they have ongoing star formation but appear to be slowly evolving compared to galaxies in denser environments. Not much is known about their star formation properties or cold gas content. In this study, we searched for molecular gas in five void galaxies. The galaxies were selected based on their relatively high IRAS fluxes or Hα line luminosities, both of which signify ongoing star formation. All five galaxies appear to be isolated and two lie within the Bootes void. We detected CO(1–0) emission from four of the five galaxies in our sample and their molecular gas masses lie between 10{sup 8} and 10{sup 9} M{sub ⊙}. We conducted follow-up Hα imaging observations of three detected galaxies using the Himalayan Chandra Telescope and determined their star formation rates (SFRs) from their Hα fluxes. The SFR varies from 0.2 to 1 M{sub ⊙} yr{sup −1}; which is similar to that observed in local galaxies. Our study indicates that although void galaxies reside in underdense regions, their disks contain molecular gas and have SFRs similar to galaxies in denser environments. We discuss the implications of our results.

  14. Model system studies of the influence of bacterial biofilm formation on mineral surface reactivity.

    Science.gov (United States)

    Brydie, J R; Wogelius, R A; Boult, S; Merrifield, C M; Vaughan, D J

    2009-01-01

    Biofilm development on mineral surfaces and related changes in surface reactivity were studied using batch and flow through experiments. An artificial groundwater was used as the primary nutrient medium, Pseudomonas aeruginosa (PAO1) was the model microbial organism and 'mineral' surfaces were kept as simple as possible by using glass or a polished quartz tile. Experiments were also completed with very low concentrations (100 mg l(-1)) of iron, Fe(2+ ), in the solution. In situ confocal laser scanning microscopy of developing colonies during the live growth phase, and of thick, mature biofilms, revealed only sporadic coverage of biofilm cells and associated polymers at the 'mineral-microbe interface'. Imaging and analysis of biofilm-conditioned surfaces doped with Fe(2+ )-rich solutions allowed the locus and form of Fe-rich mineral precipitation to be determined and show that biological surface components can cause mineral precipitation from dilute dissolved species which might otherwise remain in solution.

  15. Anisotropic sensitivity of RDX and HMX from compressive shear reactive dynamics study

    Science.gov (United States)

    Zhou, Tingting; An, Qi; Liu, Yi; Zybin, Sergey V.; Goddard, William A., III; Materials Process Simulation Center, Caltech Team

    2011-06-01

    The ReaxFF reactive force field was applied to study the mechanical and chemical behavior of RDX and HMX under combined compression and shear load. We use it to predict the anisotropic shock sensitivity of RDX and HMX single crystals. After compressed uniaxially along different shock directions, several preferable slip systems are chosen based on the maximum resolved shear stress. The pure shear deformation is applied at constant rate on these slip systems to relax the mechanical stresses until the crystal becomes amorphous. We find that the shear on a slip system with larger steric hindrance between molecules leads to larger shear stress overshoot and faster temperature increase resulting in early bond-breaking processes and initiation of chemical reactions. Our simulations confirm the effect of steric hindrance to shear on shock anisotropy of sensitivity and capture the thermochemical processes dominating the phenomena of shear-induced chemical initiation of shock- compressed explosives.

  16. Synergistic combination of biomass torrefaction and co-gasification: Reactivity studies.

    Science.gov (United States)

    Zhang, Yan; Geng, Ping; Liu, Rui

    2017-12-01

    Two typical biomass feedstocks obtained from woody wastes and agricultural residues were torrefied or mildly pyrolized in a fixed-bed reactor. Effects of the torrefaction conditions on product distributions, compositional and energetic properties of the solid products, char gasification reactivity, and co-gasification behavior between coal and torrefied solids were systematically investigated. Torrefaction pretreatment produced high quality bio-solids with not only increased energy density, but also concentrated alkali and alkaline earth metals (AAEM). As a consequence of greater retention of catalytic elements in the solid products, the chars derived from torrefied biomass exhibited a faster conversion than those derived from raw biomass during CO 2 gasification. Furthermore, co-gasification of coal/torrefied biomass blends exhibited stronger synergy compared to the coal/raw biomass blends. The results and insights provided by this study filled a gap in understanding synergy during co-gasification of coal and torrefied biomass. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Test-retest reliability of an fMRI paradigm for studies of cardiovascular reactivity.

    Science.gov (United States)

    Sheu, Lei K; Jennings, J Richard; Gianaros, Peter J

    2012-07-01

    We examined the reliability of measures of fMRI, subjective, and cardiovascular reactions to standardized versions of a Stroop color-word task and a multisource interference task. A sample of 14 men and 12 women (30-49 years old) completed the tasks on two occasions, separated by a median of 88 days. The reliability of fMRI BOLD signal changes in brain areas engaged by the tasks was moderate, and aggregating fMRI BOLD signal changes across the tasks improved test-retest reliability metrics. These metrics included voxel-wise intraclass correlation coefficients (ICCs) and overlap ratio statistics. Task-aggregated ratings of subjective arousal, valence, and control, as well as cardiovascular reactions evoked by the tasks showed ICCs of 0.57 to 0.87 (ps reliability. These findings support using these tasks as a battery for fMRI studies of cardiovascular reactivity. Copyright © 2012 Society for Psychophysiological Research.

  18. Anxiety reactivity and anxiety perseveration represent independent dimensions of anxiety vulnerability: an in vivo study.

    Science.gov (United States)

    Rudaizky, Daniel; MacLeod, Colin

    2014-01-01

    Trait anxiety is a relatively stable disposition reflecting an individual's tendency to experience anxious symptomatology, typically measured using questionnaires such as the Spielberger Trait Anxiety Inventory (STAI-T). While trait anxiety commonly is considered a unitary construct, recent questionnaire research suggests that two different dimensions of anxiety vulnerability account for independent variance in trait anxiety scores. These dimensions are anxiety reactivity (AR), reflecting the intensity of anxiety reactions to stressors, and anxiety perseveration (AP), reflecting the persistence of anxiety symptoms. This study investigated whether in vivo measures of these two facets independently contribute to anxiety vulnerability. Seventy-two participants were exposed to a novel stress task designed to yield measures of AR and AP. Regression analysis determined that these in vivo measures were unrelated to each other, and each accounted for independent variance in trait anxiety scores. The implications of these findings for the assessment and understanding of anxiety vulnerability are discussed.

  19. Pervious concrete reactive barrier for removal of heavy metals from acid mine drainage − column study

    Energy Technology Data Exchange (ETDEWEB)

    Shabalala, Ayanda N., E-mail: Ayanda.Shabalala@ump.ac.za [University of Johannesburg, PO Box 524, Auckland Park 2006 (South Africa); Ekolu, Stephen O. [University of Johannesburg, PO Box 524, Auckland Park 2006 (South Africa); Diop, Souleymane [Council for Geoscience, Private bag x112, Pretoria, 0001 (South Africa); Solomon, Fitsum [University of Johannesburg, PO Box 524, Auckland Park 2006 (South Africa)

    2017-02-05

    Highlights: • Pervious concrete raises the low pH of acid mine drainage up to 12; heavy metals precipitate. • Pervious concrete successfully removed greater than 99% of inorganic contaminants. • Ca(OH){sub 2} in pervious concrete reacts with SO{sub 4}{sup 2−} in acid mine drainage to form expansive gypsum. • Incorporating fly ash into pervious concrete mitigates damage caused by gypsum. • Pervious concrete reactive barrier offers a promising alternative method for treatment of acid mine drainage. - Abstract: This paper presents a column study conducted to investigate the potential use of pervious concrete as a reactive barrier for treatment of water impacted by mine waste. The study was done using acid mine drainage (AMD) collected from a gold mine (WZ) and a coalfield (TDB). Pervious concrete mixtures consisting of Portland cement CEM I 52.5R with or without 30% fly ash (FA) were prepared at a water-cementitious ratio of 0.27 then used to make cubes which were employed in the reactor columns. It was found that the removal efficiency levels of Al, Fe, Mn, Co and Ni were 75%, 98%, 99%, 94% and 95% for WZ; 87%, 96%, 99%, 98% and 90% for TDB, respectively. The high rate of acid reduction and metal removal by pervious concrete is attributed to dissolution of portlandite which is a typical constituent of concrete. The dominant reaction product in all four columns was gypsum, which also contributed to some removal of sulphate from AMD. Formation of gypsum, goethite, and Glauber’s salt were identified. Precipitation of metal hydroxides seems to be the dominant metal removal mechanism. Use of pervious concrete offers a promising alternative treatment method for polluted or acidic mine water.

  20. Stress Reactivity to an Electronic Version of the Trier Social Stress Test: A Pilot Study

    Directory of Open Access Journals (Sweden)

    Sage E Hawn

    2015-05-01

    Full Text Available Social stressors that rely on the inclusion of confederates (i.e., Trier Social Stress Test; TSST are often used in clinical laboratory research paradigms to elicit a measurable stress response in participants. Although effective, the TSST is labor intensive and may introduce error variance as a function of confederate race, gender, and/or response characteristics. The present study aimed to develop and validate an electronic version of the TSST (e-TSST. The primary aim was to compare the e-TSST to an e-neutral control condition; the exploratory aim was to compare the magnitude of stress response elicited by the e-TSST to that elicited by the traditional TSST. Forty-three healthy adults were randomized to the e-TSST or e-neutral condition. Subjective (participant-rated distress and objective (cortisol, heart rate and blood pressure indices of stress were collected prior to, and multiple times following, the stressor. Using archival data collected from 19 healthy participants exposed to the traditional TSST in a prior study, stress reactivity was compared between the electronic and traditional versions of the TSST. The e-TSST elicited significant increases in all measures of stress reactivity compared to the e-neutral condition, with the exception of heart rate (HR. Results showed that the magnitude of subjective distress, BP, and HR responses elicited by the e-TSST did not differ significantly from that elicited by the traditional TSST. The traditional TSST elicited significantly higher cortisol than the e-TSST. Although these findings provide initial support for the development of electronic versions of the TSST, further refinement of the e-TSST is warranted prior to broad adoption of this technology. A refined, reliable e-TSST could allow for increased utilization of the TSST by enhancing convenience, reducing labor costs, and limiting potential error variance introduced by human confederates.

  1. Individual Differences in Emotional Reactivity and Academic Achievement: A Psychophysiological Study

    Science.gov (United States)

    Scrimin, Sara; Altoè, Gianmarco; Moscardino, Ughetta; Pastore, Massimiliano; Mason, Lucia

    2016-01-01

    Factors related to grade point average (GPA) are of great importance for students' success. Yet, little is known about the impact of individual differences in emotional reactivity on students' academic performance. We aimed to examine the emotional reactivity-GPA link and to assess whether self-esteem and psychological distress moderate this…

  2. Reactive Systems

    DEFF Research Database (Denmark)

    Aceto, Luca; Ingolfsdottir, Anna; Larsen, Kim Guldstrand

    A reactive system comprises networks of computing components, achieving their goals through interaction among themselves and their environment. Thus even relatively small systems may exhibit unexpectedly complex behaviours. As moreover reactive systems are often used in safety critical systems, t...

  3. Mechanistic Reactive Burn Modeling of Solid Explosives

    Energy Technology Data Exchange (ETDEWEB)

    Y.Horie; Y.Hamate; D.Greening

    2003-04-01

    This report describes a computational framework for reactive burn modeling of solid explosives and the development of a test case where physical mechanisms represent RDX or RDX-based materials. The report is a sequel to LA-13794-MS, ''A Unifying Framework for Hot Spots and the Ignition of Energetic Materials,'' where we proposed a new approach to the building of a general purpose model that captures the essential features of the three primary origins of hot-spot formation: void collapse, shear banding, friction. The purpose of the present report is to describe the continuing task of coupling the unifying hot-spot model to hydrodynamic calculations to develop a mechanistic reactive burn model. The key components of the coupling include energy localization, the growth of hot spots, overall hot-spot behavior, and a phase-averaged mixture equation of state (EOS) in a Mie-Grueneisen form. The nucleation and growth of locally heated regions is modeled by a phenomenological treatment as well as a statistical model based on an exponential size distribution. The Mie-Grueneisen form of the EOS is one of many possible choices and is not a critical selection for implementing the model. In this report, model calculations are limited to proof-of-concept illustrations for shock loading. Results include (1) shock ignition and growth-to-detonation, (2) double shock ignition, and (3) quenching and reignition. A comparative study of Pop-plots is discussed based on the statistical model.

  4. Molecular dynamics study to identify the reactive sites of a liquid squalane surface.

    Science.gov (United States)

    Köhler, Sven P K; Reed, Stewart K; Westacott, Robin E; McKendrick, Kenneth G

    2006-06-22

    Molecular dynamics simulations of liquid squalane, C30H62, were performed, focusing in particular on the liquid-vacuum interface. These theoretical studies were aimed at identifying potentially reactive sites on the surface, knowledge of which is important for a number of inelastic and reactive scattering experiments. A united atom force field (Martin, M. G.; Siepmann, J. I. J. Phys. Chem. B 1999, 103, 4508-4517) was used, and the simulations were analyzed with respect to their interfacial properties. A modest but clearly identifiable preference for methyl groups to protrude into the vacuum has been found at lower temperatures. This effect decreases when going to higher temperatures. Additional simulations tracking the flight paths of projectiles directed at a number of randomly chosen surfaces extracted from the molecular dynamics simulations were performed. The geometrical parameters for these calculations were chosen to imitate a typical abstraction reaction, such as the reaction between ground-state oxygen atoms and hydrocarbons. Despite the preference for methyl groups to protrude further into the vacuum, Monte Carlo tracking simulations suggest, on geometric grounds, that primary and secondary hydrogen atoms are roughly equally likely to react with incoming gas-phase atoms. These geometric simulations also indicate that a substantial fraction of the scattered products is likely to undergo at least one secondary collision with hydrocarbon side chains. These results help to interpret the outcome of previous measurements of the internal and external energy distribution of the gas-phase OH products of the interfacial reaction between oxygen atoms and liquid squalane.

  5. Graph based study of allergen cross-reactivity of plant lipid transfer proteins (LTPs using microarray in a multicenter study.

    Directory of Open Access Journals (Sweden)

    Arantxa Palacín

    Full Text Available The study of cross-reactivity in allergy is key to both understanding. the allergic response of many patients and providing them with a rational treatment In the present study, protein microarrays and a co-sensitization graph approach were used in conjunction with an allergen microarray immunoassay. This enabled us to include a wide number of proteins and a large number of patients, and to study sensitization profiles among members of the LTP family. Fourteen LTPs from the most frequent plant food-induced allergies in the geographical area studied were printed into a microarray specifically designed for this research. 212 patients with fruit allergy and 117 food-tolerant pollen allergic subjects were recruited from seven regions of Spain with different pollen profiles, and their sera were tested with allergen microarray. This approach has proven itself to be a good tool to study cross-reactivity between members of LTP family, and could become a useful strategy to analyze other families of allergens.

  6. Clusters, voids and reconstructions of the cosmic web

    Science.gov (United States)

    Bos, E. G. Patrick

    2016-12-01

    The Universe is filled for 95% with dark matter and energy that we cannot see. Of the remaining 5% normal matter we can only see a small part. However, if we want to study the Universe as a whole, we will have to get to know it for 100%. We have to uncover indirectly where dark matter is hiding and what is the nature of dark energy. In this thesis we explore two such methods. The first part describes how we can use the large empty regions between galaxies, "voids", to learn more about dark energy. We converted our theoretical simulations to a model of real observations of galaxies. In this model, we perform the same measurements as we would in real observations. This way, we show that it is indeed possible to unravel the nature of dark energy. The second part is based on our computer code: BARCODE. It unites two models: a physical model of the formation of the Cosmic Web, and a description of the observational effects of (clusters of) galaxies, in particular the effect of redshift on distance measurements. It allows us to back-trace our observations to the primordial conditions. These enable us to trace all (dark) matter, also that which we did not directly observe. The result is a reconstruction of the complete Cosmic Web. In these, we studied "filaments". These objects have not yet been extensively studied. BARCODE will enable further study, e.g. by using it to find observable filaments.

  7. Cause Analysis on the Void under Slabs of Cement Concrete Pavement

    Science.gov (United States)

    Wen, Li; Zhu, Guo Xin; Baozhu

    2017-06-01

    This paper made a systematic analysis on the influence of the construction, environment, water and loads on the void beneath road slabs, and also introduced the formation process of structural void and pumping void, and summarizes the deep reasons for the bottom of the cement concrete pavement. Based on the analysis above, this paper has found out the evolution law of the void under slabs which claimed that the void usually appeared in the slab corners and then the cross joint, resulting void in the four sides with the void area under the front slab larger than the rear one.

  8. A prospective study on chemotherapy-induced hepatitis B virus reactivation in chronic HBs Ag carriers with hematologic malignancies and pre-emptive therapy with nucleoside analogues.

    Science.gov (United States)

    Yağci, Münci; Yağci, Müncý; Acar, Kadir; Acar, Kadýr; Sucak, Gülsan Türköz; Aki, Zeynep; Bozdayi, Gülendam; Haznedar, Rauf

    2006-08-01

    Chemotherapy-induced hepatitis B virus (HBV) reactivation is a serious problem in chronic HBV carriers with hematologic malignancies. In 12 patients with hematologic malignancies, we performed a prospective study to determine the effectiveness of nucleoside analogues in the pre-emptive therapy of chemotherapy-induced HBV reactivation. HBV reactivation occurred in seven patients (58.3%) whereas five of the seven patients (71%) responded to nucleoside analogue therapy. HBV reactivation-related acute liver failure and death was not observed in the present study. All five patients with chronic lymphocytic leukemia (CLL) experienced chemotherapy-induced HBV reactivation regardless of the chemotherapy regimen. Therefore, we suggest that CLL carries a significant risk of chemotherapy-induced HBV reactivation. The pre-emptive therapy of chemotherapy-induced HBV reactivation appears to be safe, based on the results of this pilot study. Pre-emptive therapy enables the definition of high-risk patients who cannot be identified by primary prophylaxis.

  9. An Efficient Bypassing Void Routing Algorithm for Wireless Sensor Network

    Directory of Open Access Journals (Sweden)

    Xunli Fan

    2015-01-01

    Full Text Available Since the sensor node’s distribution in a wireless sensor network (WSN is irregular, geographic routing protocols using the greedy algorithm can cause local minima problem. This problem may fail due to routing voids and lead to failure of data transmission. Based on the virtual coordinate mapping, this paper proposes an efficient bypassing void routing protocol to solve the control packet overhead and transmission delay in routing void of WSN, which is called EBVRPVCM. The basic idea is to transfer the random structure of void edge to a regular one through mapping the coordinates on a virtual circle. In EBVRPVCM, some strategies, executed in different regions, are selected through virtual coordinates to bypass routing void efficiently. The regular edge is established by coordinate mapping that can shorten the average routing path length and decrease the transmission delay. The virtual coordinate mapping is not affected by the real geographic node position, and the control packet overhead can be reduced accordingly. Compared with RGP and GPSR, simulation results demonstrate that EBVRPVCM can successfully find the shortest routing path with higher delivery ratio and less control packet overhead and energy consumption.

  10. Electromigration of intergranular voids in metal films for microelectronic interconnects

    CERN Document Server

    Averbuch, A; Ravve, I

    2003-01-01

    Voids and cracks often occur in the interconnect lines of microelectronic devices. They increase the resistance of the circuits and may even lead to a fatal failure. Voids may occur inside a single grain, but often they appear on the boundary between two grains. In this work, we model and analyze numerically the migration and evolution of an intergranular void subjected to surface diffusion forces and external voltage applied to the interconnect. The grain-void interface is considered one-dimensional, and the physical formulation of the electromigration and diffusion model results in two coupled fourth-order one-dimensional time-dependent PDEs. The boundary conditions are specified at the triple points, which are common to both neighboring grains and the void. The solution of these equations uses a finite difference scheme in space and a Runge-Kutta integration scheme in time, and is also coupled to the solution of a static Laplace equation describing the voltage distribution throughout the grain. Since the v...

  11. Origin of the voids in the galaxy distribution

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, Y.; Shaham, J.

    1982-11-15

    The distribution of galaxies on scales larger than approx.10 h/sup -1/ Mpc seems to be characterized by large voids, (20--40) h/sup -1/ Mpc in diameter and of amplitude deltaapprox.-(0.7--0.8). It was previously argued that the mere existence of such voids poses a severe problem to all dissipationless clustering theories. Here we show that the voids may, in fact, be a natural outcome of a dissipationless clustering scenario if both adiabatic and isothermal density perturbations exist primordially. When the nonlinear evolution of spherical voids of this type is followed for adiabatic perturbations with an index n>-1, it is seen that they become surrounded by a shell of positive density contrast. Their structure is insensitive to ..cap omega../sub 0/ while their dynamics is quite sensitive to it. The maximum peculiar velocity (relative to Hubble flow) within the void is found to be: v/sub p//v/sub H/approx.(0.4--0.5) for ..cap omega../sub 0/ = 1.0, approx.(0.2--0.25) for ..cap omega../sub 0/ = 0.45, and < or approx. =0.09 for ..cap omega../sub 0/ = 0.1.

  12. Quantitative evaluation of reactive nitrogen emissions with urbanization: a case study in Beijing megacity, China.

    Science.gov (United States)

    Xian, Chaofan; Ouyang, Zhiyun; Lu, Fei; Xiao, Yang; Li, Yanmin

    2016-09-01

    The rapid increase in anthropogenic nitrogen (N) load in urbanized environment threatens urban sustainability. In this study, we estimated the amount of reactive N (Nr) as an index of N pollution potential caused by human activities, using the megacity of Beijing as a case study. We investigated the temporal changes in Nr emissions in the environment from 2000 to 2012 using a multidisciplinary approach with quantitative evaluation. The Nr emissions presented slightly increasing during study period, and the annual emission was 0.19 Tg N, mainly resulting from fuel combustion. Nevertheless, the Nr output intensity resulting from inhabitants' livelihoods and material production had weakened over the study period. The evaluation results showed that the environmental measures to remove Nr in Beijing were efficient in most years, suggesting that progress in mitigating the growth of the Nr load in this urban environment was significant. Further measures based on N offset are suggested that could help alleviate the environmental pressure resulting from anthropogenic Nr emissions. These could provide theoretical support for the sustainable development of megacities.

  13. Experimental study on cross-reactivity of alpha-arbutin toward p-phenylenediamine and hydroquinone in guinea pigs.

    Science.gov (United States)

    To-o, Kenji; Nomura, Koji; Sugimoto, Kazuhisa; Nishimura, Takahisa; Kuriki, Takashi; Itoh, Masatoshi

    2010-05-01

    Hydroquinone (HQ) has been used as a skin-lightening cosmetic ingredient, while it has been known that HQ shows sensitizing potential and cross-reactivity toward a strong sensitizer, p-phenylenediamine (PPD). alpha-Arbutin, a glycoside of HQ (4-hydroxyphenyl alpha-D-glucopyranoside), is used worldwide as a skin-lightening agent. The aim of this study was to evaluate the cross-reactivity of alpha-arbutin toward PPD and HQ. All tests were performed using the guinea pig maximization test. In experiments on the cross-reactivity of alpha-arbutin or HQ to PPD, six animals in each group were induced with PPD at 0.1% by i.d. injection and at 1.0% by topical application. The animals were challenged with alpha-arbutin, HQ or PPD (as a positive control) at concentrations of 0.01%, 0.05% and 0.1%. In experiments on the cross-reactivity of alpha-arbutin to HQ, four animals in each group were induced with HQ at 2% by i.d. injection and at 1% by topical application. The animals were challenged with alpha-arbutin or HQ (as a positive control) at concentrations of 0.2%, 2% and 20%. The cross-reactivity toward PPD was observed with HQ (4/6) only at 0.1% challenge. However, alpha-arbutin showed no apparent cross-reactivity to either PPD or HQ even at their highest challenge concentrations. Potent sensitization was observed with PPD (6/6) even at 0.01% challenge and with HQ (3/4) at 0.2%. In conclusion, glycosylation of HQ remarkably reduced the sensitization potency of HQ and the cross-reactivity of HQ to PPD.

  14. DRIFTS study of surface reactivity to NO 2 by zinc nanoparticle aggregates and zinc hollow nanofibers

    Science.gov (United States)

    di Stasio, Stefano; Dal Santo, Vladimiro

    2006-12-01

    Zinc nanostructures synthesized with different morphologies from the same evaporation/condensation technique are studied with concern to surface reactivity to NO 2 by Diffuse Reflectance Infrared Fourier Transformed Spectroscopy (DRIFTS). Synthesis of nanopowders is obtained, according to previous work, by gas flow thermal evaporation at 540 °C of bulk Zn grains. Two types of Zn powders are obtained and studied in experiments. The first one is collected on the cold walls of the reactor as a deposit produced by thermophoretic effect. It is constituted by grains (˜10 μm) originated by the stratification of smaller aggregates (˜200 nm) and isolated primary particles (˜50 nm) born in the gas flow. The second type of powder is grown from the condensation of Zn chemical vapors within the expansion orifice of the quartz reactor after relatively long time (˜1 h) deposition process. It is constituted mainly by hollow Zn nanofibers with external and internal diameter about 100 and 60 nm. Preliminary characterization of the two types of powders is made by SEM, TEM, XRD. Thereafter, the two types of samples are studied by DRIFTS at variable temperature (VT). Comparison is made between the home-synthesized nanopowders with respect to commercial Zn standard dust. The Zn hollow nanofibers when exposed to NO 2 are found to exhibit dramatic reactivity, which is not observed at all either in the case of clustered aggregate zinc or of commercial Zn dust powders. Results indicate that, at increasing temperature from RT to 300 °C, the hollow nanofibers surface reacts distinctively with adsorbant gas NO 2, with contemporary formation of a progressively growing narrow absorption band at 2500 cm -1 and contemporary depression of a doublet (˜1600-1628 cm -1) band. In order to justify this striking spectral feature, we propose the occurring of a possible polymerization process at nanofibers surface where most probably as a consequence of pre-treatment and exposure to gas NO 2 a very

  15. Moderate alcohol consumption reduces plasma C-reactive protein and fibrinogen levels : a randomized, diet-controlled intervention study

    NARCIS (Netherlands)

    Sierksma, A.; Gaag, M.S. van der; Kluft, C.; Hendriks, H.F.J.

    2002-01-01

    Objective: To evaluate the effect of moderate alcohol consumption on the acute phase proteins C-reactive protein and fibrinogen. Design: Randomized, diet-controlled, cross-over study. Setting: The study was performed at TNO Nutrition and Food Research, Zeist, The Netherlands. Subjects: Ten

  16. THE IMPACT OF POWER COEFFICIENT OF REACTIVITY ON CANDU 6 REACTORS

    OpenAIRE

    D. KASTANYA; S. BOYLE; Hopwood, J; Park, Joo Hwan

    2013-01-01

    The combined effects of reactivity coefficients, along with other core nuclear characteristics, determine reactor core behavior in normal operation and accident conditions. The Power Coefficient of Reactivity (PCR) is an aggregate indicator representing the change in reactor core reactivity per unit change in reactor power. It is an integral quantity which captures the contributions of the fuel temperature, coolant void, and coolant temperature reactivity feedbacks. All nuclear reactor design...

  17. Study on CO2 gasification reactivity and physical characteristics of biomass, petroleum coke and coal chars.

    Science.gov (United States)

    Huo, Wei; Zhou, Zhijie; Chen, Xueli; Dai, Zhenghua; Yu, Guangsuo

    2014-05-01

    Gasification reactivities of six different carbonaceous material chars with CO2 were determined by a Thermogravimetric Analyzer (TGA). Gasification reactivities of biomass chars are higher than those of coke and coal chars. In addition, physical structures and chemical components of these chars were systematically tested. It is found that the crystalline structure is an important factor to evaluate gasification reactivities of different chars and the crystalline structures of biomass chars are less order than those of coke and coal chars. Moreover, initial gasification rates of these chars were measured at high temperatures and with relatively large particle sizes. The method of calculating the effectiveness factor η was used to quantify the effect of pore diffusion on gasification. The results show that differences in pore diffusion effects among gasification with various chars are prominent and can be attributed to different intrinsic gasification reactivities and physical characteristics of different chars. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Cross-reactivity profiles of hybrid capture II, cobas, and APTIMA human papillomavirus assays: split-sample study.

    Science.gov (United States)

    Preisler, Sarah; Rebolj, Matejka; Ejegod, Ditte Møller; Lynge, Elsebeth; Rygaard, Carsten; Bonde, Jesper

    2016-07-20

    High-risk Human Papillomavirus (HPV) testing is replacing cytology in cervical cancer screening as it is more sensitive for preinvasive cervical lesions. However, the bottleneck of HPV testing is the many false positive test results (positive tests without cervical lesions). Here, we evaluated to what extent these can be explained by cross-reactivity, i.e. positive test results without evidence of high-risk HPV genotypes. The patterns of cross-reactivity have been thoroughly studied for hybrid capture II (HC2) but not yet for newer HPV assays although the manufacturers claimed no or limited frequency of cross-reactivity. In this independent study we evaluated the frequency of cross-reactivity for HC2, cobas, and APTIMA assays. Consecutive routine cervical screening samples from 5022 Danish women, including 2859 from women attending primary screening, were tested with the three evaluated DNA and mRNA HPV assays. Genotyping was undertaken using CLART HPV2 assay, individually detecting 35 genotypes. The presence or absence of cervical lesions was determined with histological examinations; women with abnormal cytology were managed as per routine recommendations; those with normal cytology and positive high-risk HPV test results were invited for repeated testing in 18 months. Cross-reactivity to low-risk genotypes was detected in 109 (2.2 %) out of 5022 samples on HC2, 62 (1.2 %) on cobas, and 35 (0.7 %) on APTIMA with only 10 of the samples cross-reacting on all 3 assays. None of the 35 genotypes was detected in 49 (1.0 %), 162 (3.2 %), and 56 (1.1 %) samples, respectively. In primary screening at age 30 to 65 years (n = 2859), samples of 72 (25 %) out of 289 with high-risk infections on HC2 and < CIN2 histology were due to cross-reactivity. On cobas, this was 106 (26 %) out of 415, and on APTIMA 48 (21 %) out of 224. Despite manufacturer claims, all three assays showed cross-reactivity. In primary cervical screening at age ≥30 years, cross-reactivity

  19. Cue reactivity is associated with duration and severity of alcohol dependence: an FMRI study.

    Directory of Open Access Journals (Sweden)

    Zsuzsika Sjoerds

    Full Text Available INTRODUCTION: With the progression of substance dependence, drug cue-related brain activation is thought to shift from motivational towards habit pathways. However, a direct association between cue-induced brain activation and dependence duration has not yet been shown. We therefore examined the relationship between alcohol cue-reactivity in the brain, cue-induced subjective craving and alcohol dependence duration and severity. Since alcohol dependence is highly comorbid with depression/anxiety, which may modulate brain responses to alcohol cues, we also examined the relation between comorbid depression/anxiety and cue-reactivity. METHODS: We compared 30 alcohol dependent patients with 15 healthy controls and 15 depression/anxiety patients during a visual alcohol cue-reactivity task using functional magnetic resonance imaging blood oxygenated level-dependent responses and subjective craving as outcomes. Within the alcohol dependent group we correlated cue-reactivity with alcohol dependence severity and duration, with cue-induced craving and with depression/anxiety levels. RESULTS: Alcohol dependent patients showed greater cue-reactivity in motivational brain pathways and stronger subjective craving than depression/anxiety patients and healthy controls. Depression/anxiety was not associated with cue-reactivity, but depression severity in alcohol dependent patients was positively associated with craving. Within alcohol dependence, longer duration of alcohol dependence was associated with stronger cue-related activation of the posterior putamen, a structure involved in habits, whereas higher alcohol dependence severity was associated with lower cue-reactivity in the anterior putamen, an area implicated in goal-directed behavior preceding habit formation. CONCLUSION: Cue-reactivity in alcohol dependence is not modulated by comorbid depression or anxiety. More importantly, the current data confirm the hypothesis of a ventral to dorsal striatal shift

  20. Precise Void Fraction Measurement in Two-phase Flows Independent of the Flow Regime Using Gamma-ray Attenuation

    Directory of Open Access Journals (Sweden)

    E. Nazemi

    2016-02-01

    Full Text Available Void fraction is an important parameter in the oil industry. This quantity is necessary for volume rate measurement in multiphase flows. In this study, the void fraction percentage was estimated precisely, independent of the flow regime in gas–liquid two-phase flows by using γ-ray attenuation and a multilayer perceptron neural network. In all previous studies that implemented a multibeam γ-ray attenuation technique to determine void fraction independent of the flow regime in two-phase flows, three or more detectors were used while in this study just two NaI detectors were used. Using fewer detectors is of advantage in industrial nuclear gauges because of reduced expense and improved simplicity. In this work, an artificial neural network is also implemented to predict the void fraction percentage independent of the flow regime. To do this, a multilayer perceptron neural network is used for developing the artificial neural network model in MATLAB. The required data for training and testing the network in three different regimes (annular, stratified, and bubbly were obtained using an experimental setup. Using the technique developed in this work, void fraction percentages were predicted with mean relative error of <1.4%.

  1. Immunohistochemical analysis of cytokeratin expression in reactive eccrine syringofibroadenoma-like lesion: a comparative study with eccrine syringofibroadenoma.

    Science.gov (United States)

    Ohnishi, T; Watanabe, S; Nomura, K

    2000-04-01

    In addition to solitary eccrine syringofibroadenoma (ESFA), there is another type of ESFA which is associated with underlying dermatoses (reactive ESFA-like lesion). Five lesions in 4 patients of reactive ESFA-like lesion were analyzed by an immunohistochemical method using 13 kinds of anti-cytokeratin (CK) antibodies. Two cases of solitary ESFA were also studied by the same procedure for comparison. Suprabasal staining pattern of AE1 and MNF116, which stain CKs 6, 16 and 17, markers of hyperproliferative state, was observed diffusely in 5 lesions of reactive ESFA-like lesions except for focal negative staining in one case, and was observed focally in one case of solitary ESFA. Furthermore, differentiation-specific cytokeratin expression was reduced in 3 of 5 lesions of reactive ESFA-like lesions. Both ESFA and reactive ESFA showed basically similar immunoreactivity suggesting differentiation toward the dermal duct. The above slight difference in immunoreactivity between both lesions may be explained due to inflammatory infiltrates associated with underlying dermatoses.

  2. Social stimulation and corticolimbic reactivity in premenstrual dysphoric disorder: a preliminary study

    Science.gov (United States)

    2014-01-01

    Background Premenstrual dysphoric disorder (PMDD), characterized by luteal phase-induced negative affect and loss of impulse control, often results in compromised social interactions. Although amygdala activation is generally linked to negative affect, increased amygdala reactivity to aversive stimuli in the luteal phase has not been consistently reported in PMDD. We tested the hypothesis that amygdala hyper-reactivity in PMDD is symptom specific, rather than generalized, and linked to socially relevant stimuli. Blood oxygenation level dependent signal changes during exposure to negative images with social and non-social content were evaluated in the mid-follicular and late luteal phase of the menstrual cycle. Fourteen women with PMDD and 13 healthy controls participated. Results When compared with healthy controls, women with PMDD in the luteal phase had enhanced reactivity to social stimuli compared to non-social stimuli in the amygdala and insula, but attenuated reactivity in the anterior cingulate cortex. Functional couplings between emotion processing and controlling areas were significantly different, being positive in women with PMDD and negative in healthy controls. Changes in progesterone levels in women with PMDD correlated positively with altered amygdala reactivity. Conclusions Socially relevant aversive stimulation elicited enhanced activity in affective processing brain regions that were functionally coupled to compromised activity in cognitive control areas. Because increased reactivity correlated positively with alterations in ovarian steroid levels, data preliminary support the hypothesis that enhanced progesterone sensitivity in PMDD affects corticolimbic processing of social emotions. PMID:24572042

  3. Effects of voids on thermal-mechanical reliability of lead-free solder joints

    Directory of Open Access Journals (Sweden)

    Benabou Lahouari

    2014-06-01

    Full Text Available Reliability of electronic packages has become a major issue, particularly in systems used in electrical or hybrid cars where severe operating conditions must be met. Many studies have shown that solder interconnects are critical elements since many failure mechanisms originate from their typical response under thermal cycles. In this study, effects of voids in solder interconnects on the electronic assembly lifetime are estimated based on finite element simulations.

  4. Void formation in pure aluminium irradiated with high-energetic electron beams and gamma-quanta

    DEFF Research Database (Denmark)

    Gan, V. V.; Ozhigou, L. S.; Yamnitsky, V. A.

    1983-01-01

    The spatial distribution of displaced atoms and helium atoms and also the spectra of damaging energies of primary displaced atoms in a thick aluminium target irradiated with electrons of 225 MeV energy were calculated. Pure aluminium (99.9999%) irradiated up to 0.04 dose was studied by electron-m......-microscopy. Voids of size 5 to 40 nm were obtained and their vacancy nature was estimated. The dislocation structure of the material was studied...

  5. Tunnel and Subsurface Void Detection and Range to Target Measurement

    Energy Technology Data Exchange (ETDEWEB)

    Phillip B. West

    2009-06-01

    Engineers and technicians at the Idaho National Laboratory invented, designed, built and tested a device capable of detecting and measuring the distance to, an underground void, or tunnel. Preliminary tests demonstrated positive detection of, and range to, a void thru as much as 30 meters of top-soil earth. Device uses acoustic driving point impedance principles pioneered by the Laboratory for well-bore physical properties logging. Data receipts recorded by the device indicates constructive-destructive interference patterns characteristic of acoustic wave reflection from a downward step-change in impedance mismatch. Prototype tests demonstrated that interference patterns in receipt waves could depict the patterns indicative of specific distances. A tool with this capability can quickly (in seconds) indicate the presence and depth/distance of a void or tunnel. Using such a device, border security and military personnel can identify threats of intrusion or weapons caches in most all soil conditions including moist and rocky.

  6. Effectiveness of reactive oral cholera vaccination in rural Haiti: a case-control study

    Science.gov (United States)

    Ivers, Louise C; Hilaire, Isabelle J; Teng, Jessica E; Almazor, Charles P; Jerome, J Gregory; Ternier, Ralph; Boncy, Jacques; Buteau, Josiane; Murray, Megan B; Harris, Jason B; Franke, Molly F

    2015-01-01

    Background Between April and June 2012, a reactive cholera vaccination campaign was conducted in Haiti using an oral inactivated bivalent whole-cell vaccine (BivWC). Methods We conducted a case-control study to estimate field effectiveness of the vaccine. Cases had acute watery diarrhea, sought treatment at one of three participating cholera treatment units from October 24, 2012 through March 9, 2014, and had a stool sample positive for cholera by culture. For each case, four controls (individuals who did not seek treatment for acute watery diarrhea) were matched by location of residence, calendar time, and age. We also conducted a bias-indicator case-control study to assess the likelihood of bias in the vaccine effectiveness (VE) study. Findings During the study period, 114 eligible individuals presented with acute watery diarrhea and were enrolled. 47 were analyzed as cases in the VE case-control study and 42 as cases in the bias-indicator study. In multivariable analyses, VE was 63% [95% confidence interval (CI): 8%–85%] by self-reported vaccination and 58% [95% CI: 13%–80%] for verified vaccination. Neither self-reported nor verified vaccination was significantly associated with non-cholera diarrhea (VE: 18% [95% CI: −208%–−78%] by self-report and −21% [95%CI: −238%–57%] for verified vaccination). Interpretation BivWC oral cholera vaccine was effective in protecting against cholera in Haiti during the study period –from 4 through 24 months after vaccination. Vaccination is an important component of epidemic cholera control efforts. Funding National Institutes of Health, Delivering Oral Vaccines Effectively project, Department of Global Health and Social Medicine at Harvard Medical School. PMID:25701994

  7. Ozone reactivity of biogenic volatile organic compound (BVOC) emissions during the Southeast Oxidant and Aerosol Study (SOAS)

    Science.gov (United States)

    Park, J.; Guenther, A. B.; Helmig, D.

    2013-12-01

    Recent studies on atmospheric chemistry in the forest environment showed that the total reactivity by biogenic volatile organic compound (BVOC) emission is still not well understood. During summer 2013, an intensive field campaign (Southeast Oxidant and Aerosol Study - SOAS) took place in Alabama, U.S.A. In this study, an ozone reactivity measurement system (ORMS) was deployed for the direct determination of the reactivity of foliage emissions. The ORMS is a newly developed measurement approach, in which a known amount of ozone is added to the ozone-free air sample stream, with the ORMS measuring ozone concentration difference between before and after a glass flask flow tube reaction vessel (2-3 minutes of residence time). Emissions were also collected onto adsorbent cartridges to investigate the discrepancy between total ozone reactivity observation and reactivity calculated from identified BVOC. Leaf and canopy level experiments were conducted by deploying branch enclosures on the three dominant tree species at the site (i.e. liquidambar, white oak, loblolly pine) and by sampling ambient air above the forest canopy. For the branch enclosure experiments, BVOC emissions were sampled from a 70 L Teflon bag enclosure, purged with air scrubbed for ozone, nitrogen oxides. Each branch experiment was performed for 3-5 days to collect at least two full diurnal cycle data. In addition, BVOCs were sampled using glass tube cartridges for 2 hours during daytime and 3 - 4 hours at night. During the last week of campaign, the inlet for the ORMS was installed on the top of scaffolding tower (~30m height). The ozone loss in the reactor showed distinct diurnal cycle for all three tree species investigated, and ozone reactivity followed patterns of temperature and light intensity.

  8. Surface reactivity of Ge[111] for organic functionalization by means of a radical-initiated reaction: A DFT study

    Energy Technology Data Exchange (ETDEWEB)

    Rubio-Pereda, Pamela, E-mail: rubio.pereda@gmail.com [Centro de Investigación Científica y de Educación Superior de Ensenada 3918, Código Postal 22860, Ensenada, Baja California (Mexico); Takeuchi, Noboru, E-mail: takeuchi@cnyn.unam.mx [Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, Apartado Postal 14, Código Postal 22800, Ensenada, Baja California (Mexico)

    2016-08-30

    Highlights: • The surface reactivity of the Ge [111] surface is studied with DFT for the attachment of organic molecules by means of a radical-initiated reaction. • A hydrogen vacancy in the hydrogen terminated Ge [111] surface exhibits an accumulation of charge and electron pairing. • These characteristics make the hydrogen vacancy less reactive for the attachment of unsaturated organic molecules. • The adsorption of acetylene is probable to occur while the adsorption of ethylene and styrene is substantially less probable to occur. • The hydrogen terminated Ge [111] surface is found to be less reactive than its two-dimensional analogue, the hydrogen-terminated germanene. - Abstract: The study of interfacial chemistry at semiconductor surfaces has become an important area of research. Functionalities such as molecular recognition, biocompatibility of surfaces, and molecular computing, could be achieved by the combinations of organic chemistry with the semiconductor technology. One way to accomplish this goal is by means of organic functionalization of semiconductor surfaces such as the bulk-terminated germanium surfaces, more specifically the Ge[111]. In this work, we theoretically study, by applying density functional theory, the surface reactivity of the bulk-terminated Ge[111] surface for organic functionalization by means of a radical-initiated reaction of unsaturated molecules such as acetylene, ethylene and styrene with a hydrogen vacancy on a previously hydrogen-terminated Ge[111] surface. Results derived from this work are compared with those obtained in our previous calculations on the germanene surface, following the same chemical route. Our calculations show an accumulation of electronic charge at the H-vacancy having as a result electron pairing due to strong lattice-electron coupling and therefore a diminished surface reactivity. Calculation of the transition states for acetylene and ethylene indicates that the surface reactivity of the

  9. Void statistics of the CfA redshift survey

    Science.gov (United States)

    Vogeley, Michael S.; Geller, Margaret J.; Huchra, John P.

    1991-01-01

    Clustering properties of two samples from the CfA redshift survey, each containing about 2500 galaxies, are studied. A comparison of the velocity distributions via a K-S test reveals structure on scales comparable with the extent of the survey. The void probability function (VPF) is employed for these samples to examine the structure and to test for scaling relations in the galaxy distribution. The galaxy correlation function is calculated via moments of galaxy counts. The shape and amplitude of the correlation function roughly agree with previous determinations. The VPFs for distance-limited samples of the CfA survey do not match the scaling relation predicted by the hierarchical clustering models. On scales not greater than 10/h Mpc, the VPFs for these samples roughly follow the hierarchical pattern. A variant of the VPF which uses nearly all the data in magnitude-limited samples is introduced; it accounts for the variation of the sampling density with velocity in a magnitude-limited survey.

  10. Relation of Serum Leptin and Adiponectin Level to Serum C-Reactive Protein: The INTERLIPID Study

    Directory of Open Access Journals (Sweden)

    Yasuyuki Nakamura

    2013-01-01

    Full Text Available Objective. Despite considerable study, the relevance of leptin and adiponectin for atherosclerosis development is still unsettled. We investigated relations of serum leptin and adiponectin to serum C-reactive protein (CRP, using the INTERLIPID dataset on Japanese emigrants living in Hawaii and Japanese in Japan. Design and Methods. Serum leptin, adiponectin, and CRP were measured by standardized methods in men and women of ages 40 to 59 years from two population samples, one Japanese-American in Hawaii (83 men, 89 women and the other Japanese in central Japan (111 men, 104 women. Participants with CRP >10 mg/L were excluded. Results. Sex-specific multiple linear regression analyses, with log-transformed leptin and adiponectin (log-leptin, log-adipo, site (Hawaii = 1, Japan = 0, SBP, HbA1c, smoking (cigarettes/day, and physical activity index score of the Framingham Offspring Study as covariates, showed that log-leptin directly related and log-adipo inversely related to log-CRP for both sexes (Ps < 0.05 to <0.01. Addition to the model of BMI and interaction terms (BMI × log-leptin, BMI × log-adipo, SITE × log-leptin, SITE × log-adipo resulted in disappearance of statistical significance except for direct relation of log-leptin to log-CRP in men (P=0.006. Conclusions. Leptin directly related to CRP independent of BMI and other confounding factors in men but not in women.

  11. Pervious concrete reactive barrier for removal of heavy metals from acid mine drainage - column study.

    Science.gov (United States)

    Shabalala, Ayanda N; Ekolu, Stephen O; Diop, Souleymane; Solomon, Fitsum

    2017-02-05

    This paper presents a column study conducted to investigate the potential use of pervious concrete as a reactive barrier for treatment of water impacted by mine waste. The study was done using acid mine drainage (AMD) collected from a gold mine (WZ) and a coalfield (TDB). Pervious concrete mixtures consisting of Portland cement CEM I 52.5R with or without 30% fly ash (FA) were prepared at a water-cementitious ratio of 0.27 then used to make cubes which were employed in the reactor columns. It was found that the removal efficiency levels of Al, Fe, Mn, Co and Ni were 75%, 98%, 99%, 94% and 95% for WZ; 87%, 96%, 99%, 98% and 90% for TDB, respectively. The high rate of acid reduction and metal removal by pervious concrete is attributed to dissolution of portlandite which is a typical constituent of concrete. The dominant reaction product in all four columns was gypsum, which also contributed to some removal of sulphate from AMD. Formation of gypsum, goethite, and Glauber's salt were identified. Precipitation of metal hydroxides seems to be the dominant metal removal mechanism. Use of pervious concrete offers a promising alternative treatment method for polluted or acidic mine water. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Feeding forward to a 'miracle day' – a pilot study of video feedforward in reactive attachment disorder.

    Science.gov (United States)

    Gorski, Charlotta; Minnis, Helen

    2014-07-01

    Video feedforward is a solution-focused intervention used to improve desired behaviour. We present two case studies of using video feedforward in reactive attachment disorder. Children with reactive attachment disorder, their caregivers and their clinician completed storyboards of behaviours desired during a 'miracle day' and filmed the individual scenes. These scenes were edited to a prolonged sequence of successful behaviour which was fed back to the child and their caregiver using principles of video interaction guidance. Families reported major improvements in the targeted behaviours, usually within a week of filming the 'miracle day'. © The Author(s) 2013.

  13. Synthesis of reactive nucleic acid analogues and their application for the study of structure and functions of biopolymers

    Energy Technology Data Exchange (ETDEWEB)

    Kanevskii, Igor' E; Kuznetsova, Svetlana A [Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow (Russian Federation)

    1998-07-31

    Data on the synthesis of reactive derivatives of nucleic acid analogues and their application for the study of structure and functions of biopolymers are generalised. The main types of such analogues including photoactivated reagents containing azidoaryl, halogeno, and thiol groups, psoralen and its derivatives, platinum-based reagents, and nucleic acid analogues containing substituted pyrophosphate or acyl phosphate internucleotide groups are presented. The mechanisms of interaction of these compounds with proteins and nucleic acids are considered. The prospects for the in vivo application of reactive nucleic acids in various systems are discussed. The bibliography includes 76 references.

  14. Voids and constraints on nonlinear clustering of galaxies

    Science.gov (United States)

    Vogeley, Michael S.; Geller, Margaret J.; Park, Changbom; Huchra, John P.

    1994-01-01

    Void statistics of the galaxy distribution in the Center for Astrophysics Redshift Survey provide strong constraints on galaxy clustering in the nonlinear regime, i.e., on scales R equal to or less than 10/h Mpc. Computation of high-order moments of the galaxy distribution requires a sample that (1) densely traces the large-scale structure and (2) covers sufficient volume to obtain good statistics. The CfA redshift survey densely samples structure on scales equal to or less than 10/h Mpc and has sufficient depth and angular coverage to approach a fair sample on these scales. In the nonlinear regime, the void probability function (VPF) for CfA samples exhibits apparent agreement with hierarchical scaling (such scaling implies that the N-point correlation functions for N greater than 2 depend only on pairwise products of the two-point function xi(r)) However, simulations of cosmological models show that this scaling in redshift space does not necessarily imply such scaling in real space, even in the nonlinear regime; peculiar velocities cause distortions which can yield erroneous agreement with hierarchical scaling. The underdensity probability measures the frequency of 'voids' with density rho less than 0.2 -/rho. This statistic reveals a paucity of very bright galaxies (L greater than L asterisk) in the 'voids.' Underdensities are equal to or greater than 2 sigma more frequent in bright galaxy samples than in samples that include fainter galaxies. Comparison of void statistics of CfA samples with simulations of a range of cosmological models favors models with Gaussian primordial fluctuations and Cold Dark Matter (CDM)-like initial power spectra. Biased models tend to produce voids that are too empty. We also compare these data with three specific models of the Cold Dark Matter cosmogony: an unbiased, open universe CDM model (omega = 0.4, h = 0.5) provides a good match to the VPF of the CfA samples. Biasing of the galaxy distribution in the 'standard' CDM model

  15. The effects of void handling on geodetic mass balances

    Science.gov (United States)

    McNabb, Robert; Nuth, Chris; Kääb, Andreas; Girod, Luc

    2017-04-01

    Glacier mass balance is a direct expression of climate change, and has implications for changes in sea level, ocean chemistry, and oceanic and terrestrial ecosystems. Glacier mass balance has traditionally been measured through in-situ measurements of surface elevation change on a glacier surface. To estimate changes on a larger spatial scale, however, in-situ measurement is not feasible, and aerial or satellite measurements of digital elevation models (DEMs) over glaciers have been used recently in order to supplement and extend ground-based measurements. Though the resolution and accuracy of these products generally increases with time, there are still often gaps ("voids") in the data, as well as errors and biases that must be addressed. The occurrence and distribution of these voids is at least partially dependent on the sensor or acquisition method used to generate the source DEMs. For example, for optical stereo DEMs, voids can be especially frequent in the accumulation area of glaciers, impacting elevation measurements and the resulting estimates of glacier volume change to an unknown degree. Several methods for handling voids in elevation datasets have been proposed and implemented in the literature, though direct investigation of the uncertainty associated with these methods is generally not reported. In order to estimate the uncertainties associated with various methods for filling voids in elevation data, we simulate typical voids in high-resolution spatially-complete DEMs of glaciers in south-central Alaska (covering the Alaska Range, Chugach, Kenai, and Wrangel Mountains), USA. This region is home to over 7000 individual glaciers covering over 23000 km2, ranging in elevation from sea level to over 6000 m, and representing many different glacier types including surging glaciers, advancing and retreating tidewater glaciers, and large and small valley glaciers. As such, it presents an ideal test region to investigate the impact of various methods for void

  16. Laboratory chamber studies on the formation of organosulfates from reactive uptake of monoterpene oxides.

    Science.gov (United States)

    Iinuma, Yoshiteru; Böge, Olaf; Kahnt, Ariane; Herrmann, Hartmut

    2009-09-28

    Evidence from field measurements suggests that organosulfates contribute substantially to ambient secondary organic aerosol (SOA) and might dominate a considerable fraction of total sulfur in tropospheric particles. While alcohols and epoxides are suggested to be most likely precursors for organosulfates in SOA, their reactivity in acidic particles and their potential for organosulfate formation are still unclear. In the present study, a series of aerosol chamber experiments was performed to investigate the formation of organosulfates from reactive uptake of monoterpene oxides (alpha-pinene oxide and beta-pinene oxide) and acid catalysed isomerisation compounds of alpha-pinene oxide (campholenic aldehyde and carveol) on neutral and acidic sulfate particles. Organosulfate formation was observed only under acidic conditions for both monoterpene oxides and, to a lesser extent, campholenic aldehyde, indicating that epoxides most likely serve as precursors for some of the organosulfates reported from both ambient and laboratory SOA samples. Structures of organosulfates were elucidated by comparing the tandem mass spectrometric, accurate mass and ion mobility data obtained for both the synthesised reference compounds and aerosol chamber-generated organosulfates. In the experiment performed using beta-pinene oxide and acidic sulfate seed particles, an organosulfate with a sulfate group at a tertiary carbon atom accounts for 64% of the detected organosulfates. In contrast, an organosulfate with a sulfate group at a secondary carbon atom accounts for 80% of the detected organosulfates in the sample from alpha-pinene oxide/acidic sulfate particle experiment. The concentration of beta-pinene-derived organosulfates was higher than known alpha-pinene oxidation products such as pinic acid and pinonic acid in an ambient aerosol sample collected at a Norwegian spruce forest site during the summer time, ranging up to 23 ng m(-3). Furthermore, alpha-pinene oxide is found to

  17. Assessment of void swelling in austenitic stainless steel PWR core internals.

    Energy Technology Data Exchange (ETDEWEB)

    Chung, H. M.; Energy Technology

    2006-01-31

    As many pressurized water reactors (PWRs) age and life extension of the aged plants is considered, void swelling behavior of austenitic stainless steel (SS) core internals has become the subject of increasing attention. In this report, the available database on void swelling and density change of austenitic SSs was critically reviewed. Irradiation conditions, test procedures, and microstructural characteristics were carefully examined, and key factors that are important to determine the relevance of the database to PWR conditions were evaluated. Most swelling data were obtained from steels irradiated in fast breeder reactors at temperatures >385 C and at dose rates that are orders of magnitude higher than PWR dose rates. Even for a given irradiation temperature and given steel, the integral effects of dose and dose rate on void swelling should not be separated. It is incorrect to extrapolate swelling data on the basis of 'progressive compounded multiplication' of separate effects of factors such as dose, dose rate, temperature, steel composition, and fabrication procedure. Therefore, the fast reactor data should not be extrapolated to determine credible void swelling behavior for PWR end-of-life (EOL) or life-extension conditions. Although the void swelling data extracted from fast reactor studies is extensive and conclusive, only limited amounts of swelling data and information have been obtained on microstructural characteristics from discharged PWR internals or steels irradiated at temperatures and at dose rates comparable to those of a PWR. Based on this relatively small amount of information, swelling in thin-walled tubes and baffle bolts in a PWR is not considered a concern. As additional data and relevant research becomes available, the newer results should be integrated with existing data, and the worthiness of this conclusion should continue to be scrutinized. PWR baffle reentrant corners are the most likely location to experience high swelling

  18. Childhood trauma, psychosis liability and social stress reactivity: a virtual reality study.

    Science.gov (United States)

    Veling, W; Counotte, J; Pot-Kolder, R; van Os, J; van der Gaag, M

    2016-12-01

    Childhood trauma is associated with higher risk for mental disorders, including psychosis. Heightened sensitivity to social stress may be a mechanism. This virtual reality study tested the effect of childhood trauma on level of paranoid ideations and distress in response to social stress, in interaction with psychosis liability and level of social stress exposure. Seventy-five individuals with higher psychosis liability (55 with recent onset psychotic disorder and 20 at ultra-high risk for psychosis) and 95 individuals with lower psychosis liability (42 siblings and 53 controls) were exposed to a virtual café in five experiments with 0-3 social stressors (crowded, other ethnicity and hostility). Paranoid ideation was measured after each experiment. Subjective distress was self-rated before and after experiments. Multilevel random regression analyses were used to test main effects of childhood trauma and interaction effects. Childhood trauma was more prevalent in individuals with higher psychosis liability, and was associated with higher level of (subclinical) psychotic and affective symptoms. Individuals with a history of childhood trauma responded with more subjective distress to virtual social stress exposures. The effects of childhood trauma on paranoia and subjective distress were significantly stronger when the number of virtual environmental stressors increased. Higher psychosis liability increased the effect of childhood trauma on peak subjective distress and stress reactivity during experiments. Childhood trauma is associated with heightened social stress sensitivity and may contribute to psychotic and affective dysregulation later in life, through a sensitized paranoid and stress response to social stressors.

  19. Differential vs. absolute UV absorbance approaches in studying NOM reactivity in DBPs formation: comparison and applicability.

    Science.gov (United States)

    Roccaro, Paolo; Vagliasindi, Federico G A

    2009-02-01

    Differential absorbance at wavelengths near 272 nm (-DeltaA272) has been used to track the halogenation of NOM, but its performance for different drinking water sources before and after water treatment processes has not been thoroughly ascertained. In this study, the behavior of -DeltaA272 during the halogenation process was determined to be strongly correlated with DBPs' concentrations regardless of the NOM properties. However, chlorination of different NOM samples resulted in different patterns when DBP concentrations were plotted vs. -DeltaA272. In order to quantify the reactivity of NOM in DBPs formation an alternative index, denoted as -DeltaA272(t=2 h), that is the differential absorbance at 272 nm obtained at 2 h of reaction time and pH 7.0, was proposed. This parameter was strongly correlated with DBPs' concentrations regardless of the major chlorination conditions (chlorine dose, water temperature) and NOM properties (raw, treated and fractionated samples). Its performance was found better than that of other widely used surrogate parameters (i.e. DOC, SUVA254, A254, A272) and it presents several options for field applications.

  20. A test on reactive force fields for the study of silica dimerization reactions

    Energy Technology Data Exchange (ETDEWEB)

    Moqadam, Mahmoud; Riccardi, Enrico; Trinh, Thuat T.; Åstrand, Per-Olof; Erp, Titus S. van, E-mail: titus.van.erp@ntnu.no [Department of Chemistry, Norwegian University of Science and Technology (NTNU), Høgskoleringen 5, Realfagbygget D3-117, 7491 Trondheim (Norway)

    2015-11-14

    We studied silica dimerization reactions in the gas and aqueous phase by density functional theory (DFT) and reactive force fields based on two parameterizations of ReaxFF. For each method (both ReaxFF force fields and DFT), we performed constrained geometry optimizations, which were subsequently evaluated in single point energy calculations using the other two methods. Standard fitting procedures typically compare the force field energies and geometries with those from quantum mechanical data after a geometry optimization. The initial configurations for the force field optimization are usually the minimum energy structures of the ab initio database. Hence, the ab initio method dictates which structures are being examined and force field parameters are being adjusted in order to minimize the differences with the ab initio data. As a result, this approach will not exclude the possibility that the force field predicts stable geometries or low transition states which are realistically very high in energy and, therefore, never considered by the ab initio method. Our analysis reveals the existence of such unphysical geometries even at unreactive conditions where the distance between the reactants is large. To test the effect of these discrepancies, we launched molecular dynamics simulations using DFT and ReaxFF and observed spurious reactions for both ReaxFF force fields. Our results suggest that the standard procedures for parameter fitting need to be improved by a mutual comparative method.

  1. Study of Na-Montmorillonite–Polyamide Fiber/Polypropylene Hybrid Composite Prepared by Reactive Melt Mixing

    Directory of Open Access Journals (Sweden)

    Samia Kerakra

    2017-01-01

    Full Text Available Hybrid composites of polypropylene (PP/sodium montmorillonite (Na-MMT/short polyamide fibers (PAfs were prepared by reactive melt mixing in a Brabender plastograph. To enhance filler interactions within polypropylene, a functionalizing agent (FA and a coupling agent were added to the Na-MMT and PAfs, respectively. An organic peroxide/sulfur mixture and tetramethylthiuram disulfide as an activator for sulfur were used to functionalize Na-MMT; on the other hand, the PAfs surface was treated using stearic acid. The aim of this study is to investigate how the morphology and the structural properties of 3, 5, and 7 wt% recycled functionalized sodium montmorillonite nanocomposites (f-Na-MMT are affected by the presence of 5 wt% treated short polyamide fibers (t-PAfs. According to the obtained results, 5 wt% recycled f-Na-MMT/5 wt% t-PAfs/PP hybrid composite showed Na-MMT layers exfoliation. The nucleating effect of f-Na-MMT and t-PAfs was indicated by the differential scanning calorimetry (DSC measurements. Morphological analysis of the hybrid composites was performed using scanning electron microscope (SEM and optical polarized microscopy (POM, showing a good dispersion of the fibers with an interesting interfacial adhesion between the PP and t-PAfs phases. Hybrid composites of PP/f-Na-MMT/t-PAfs are considered for automotive industry.

  2. Association between preterm delivery and subsequent C-reactive protein: a retrospective cohort study.

    Science.gov (United States)

    Hastie, Claire E; Smith, Gordon C S; Mackay, Daniel F; Pell, Jill P

    2011-12-01

    We sought to determine whether giving birth preterm is associated with raised maternal C-reactive protein (CRP) in later life and whether the association is specific to indicated or spontaneous delivery. This was a Scotland-wide retrospective cohort study of 1124 women who had a first pregnancy resulting in a singleton, liveborn infant delivered between 24-43 weeks' gestation. Linear regression analysis was used to examine the association between preterm delivery and subsequent CRP concentration. The difference in CRP between women who delivered term and preterm was nonsignificant on univariate analysis (beta coefficient 0.04, P = .18) but was statistically significant following adjustment for potential confounders (beta coefficient 0.05, P < .05). On subgroup analysis the association was specific to women who had had indicated preterm delivery (unadjusted beta coefficient 0.09, P < .01; adjusted beta coefficient 0.09, P < .01). Women who undergo indicated preterm delivery are at increased risk of raised CRP in later life. Copyright © 2011 Mosby, Inc. All rights reserved.

  3. Evaluation of C-reactive protein as an inflammatory biomarker in rabbits for vaccine nonclinical safety studies

    NARCIS (Netherlands)

    Destexhe, E.; Prinsen, M.K.; Schöll, I. van; Kuper, C.F.; Garçon, N.; Veenstra, S.; Segal, L.

    2013-01-01

    Introduction: Inflammatory reactions are one of the potential safety concerns that are evaluated in the framework of vaccine safety testing. In nonclinical studies, the assessment of the inflammation relies notably on the measurement of biomarkers. C-reactive protein (CRP) is an acute-phase plasma

  4. A Computational Study of Structure and Reactivity of N-Substitued-4-Piperidones Curcumin Analogues and Their Radical Anions

    Directory of Open Access Journals (Sweden)

    Maximiliano Martínez-Cifuentes

    2016-12-01

    Full Text Available In this work, a computational study of a series of N-substitued-4-piperidones curcumin analogues is presented. The molecular structure of the neutral molecules and their radical anions, as well as their reactivity, are investigated. N-substituents include methyl and benzyl groups, while substituents on the aromatic rings cover electron-donor and electron-acceptor groups. Substitutions at the nitrogen atom do not significantly affect the geometry and frontier molecular orbitals (FMO energies of these molecules. On the other hand, substituents on the aromatic rings modify the distribution of FMO. In addition, they influence the capability of these molecules to attach an additional electron, which was studied through adiabatic (AEA and vertical electron affinities (VEA, as well as vertical detachment energy (VDE. To study electrophilic properties of these structures, local reactivity indices, such as Fukui (f+ and Parr (P+ functions, were calculated, and show the influence of the aromatic rings substituents on the reactivity of α,β-unsaturated ketones towards nucleophilic attack. This study has potential implications for the design of curcumin analogues based on a 4-piperidone core with desired reactivity.

  5. Acetic acid recovery from fast pyrolysis oil. An exploratory study on liquid-liquid reactive extraction using aliphatic tertiary amines

    NARCIS (Netherlands)

    Mahfud, F. H.; van Geel, F. P.; Venderbosch, R. H.; Heeres, H. J.

    2008-01-01

    Flash pyrolysis oil or Bio-oil (BO), obtained by flash pyrolysis of lignocellulosic biomass, is very acidic in nature. The major component responsible for this acidity is acetic acid, present in levels up to 2-10 wt%. Here, we report an exploratory study on BO upgrading by reactive extraction of

  6. Mechanisms of activation of phenacetin to reactive metabolites by cytochrome P-450 : a theoretical study involving radical intermediates

    NARCIS (Netherlands)

    Koymans, L.; Lenthe, J.H.; Donné-op Den Kelder, G M; Vermeulen, N P

    The cytochrome P-450-mediated activation of phenacetin (PHEN) to reactive intermediates by two hypothetical mechanisms has been studied by use of SV 6-31G ab initio energy and spin distribution calculations. In our calculations, the cytochrome P-450 enzyme system has been substituted by a singlet

  7. Meat consumption and its association with C-reactive protein and incident type 2 diabetes : The Rotterdam Study

    NARCIS (Netherlands)

    Woudenbergh, van G.J.; Kuijsten, A.; Tigcheler, B.; Sijbrands, E.J.G.; Rooij, van F.J.A.; Hofman, A.; Witteman, J.C.M.; Feskens, E.J.M.

    2012-01-01

    OBJECTIVE To investigate whether intake of different types of meat is associated with circulating C-reactive protein (CRP) and risk of type 2 diabetes in a prospective cohort study. RESEARCH DESIGN AND METHODS Our analysis included 4,366 Dutch participants who did not have diabetes at baseline.

  8. Meat consumption and its association with C-reactive protein and incident type 2 diabetes: The Rotterdam study

    NARCIS (Netherlands)

    G.J. van Woudenbergh (Geertruida); A. Kuijsten (Anneleen); B. Tigcheler (Basia); E.J.G. Sijbrands (Eric); F.J.A. van Rooij (Frank); A. Hofman (Albert); J.C.M. Witteman (Jacqueline); E.J.M. Feskens (Edith)

    2012-01-01

    textabstractOBJECTIVE - To investigate whether intake of different types of meat is associated with circulating C-reactive protein (CRP) and risk of type 2 diabetes in a prospective cohort study. RESEARCH DESIGN AND METHODS - Our analysis included 4,366 Dutch participants who did not have diabetes

  9. Influence of root canal sealer on the radiographic appearance of filling voids in maxillary single-rooted teeth

    Directory of Open Access Journals (Sweden)

    Augusto Bodanezi

    2012-08-01

    Full Text Available OBJECTIVE: This study compared the influence of three epoxy resin-based sealers with distinct radiopacities on the observers' ability to detect root canal filling voids during radiographic analysis. MATERIAL AND METHODS: The root canals of 48 extracted maxillary canines were prepared and divided into three groups. Each group was laterally condensed with one sealer (AH Plus®, Acroseal® or a non-radiopaque sealer, and a longitudinal void was simulated in half of the specimens from each group (n=8. Buccolingual radiographs were obtained and randomly interpreted for voids by a radiologist and an endodontist in a blinded fashion. Teeth were cut and inspected under a microscope to confirm the position of void. Differences in sensitivity and specificity between groups and examiners were compared using the Fisher's Exact and McNemar tests, respectively (α=0.05. RESULTS: Significantly lower sensitivity levels (p<0.05 were observed in the coronal portion of fillings performed with both radiopaque sealers. Specificity values for Acroseal® were significantly higher (p<0.05 in the coronal and apical portions of fillings. CONCLUSIONS: The type of root canal sealer can affect the observers' ability to detect root canal filling voids during radiographic analysis of upper single-rooted teeth.

  10. Influence of root canal sealer on the radiographic appearance of filling voids in maxillary single-rooted teeth.

    Science.gov (United States)

    Bodanezi, Augusto; Munhoz, Etiene Andrade; Capelozza, Ana Lúcia Álvares; Bernardineli, Norberti; Moraes, Ivaldo Gomes de; Garcia, Roberto Brandão; Bramante, Clovis Monteiro

    2012-01-01

    This study compared the influence of three epoxy resin-based sealers with distinct radiopacities on the observers' ability to detect root canal filling voids during radiographic analysis. The root canals of 48 extracted maxillary canines were prepared and divided into three groups. Each group was laterally condensed with one sealer (AH Plus®, Acroseal® or a non-radiopaque sealer), and a longitudinal void was simulated in half of the specimens from each group (n=8). Buccolingual radiographs were obtained and randomly interpreted for voids by a radiologist and an endodontist in a blinded fashion. Teeth were cut and inspected under a microscope to confirm the position of void. Differences in sensitivity and specificity between groups and examiners were compared using the Fisher's Exact and McNemar tests, respectively (α=0.05). Significantly lower sensitivity levels (p<0.05) were observed in the coronal portion of fillings performed with both radiopaque sealers. Specificity values for Acroseal® were significantly higher (p<0.05) in the coronal and apical portions of fillings. The type of root canal sealer can affect the observers' ability to detect root canal filling voids during radiographic analysis of upper single-rooted teeth.

  11. Determination of the equivalent intergranular void ratio - Application to the instability and the critical state of silty sand

    Science.gov (United States)

    Nguyen, Trung-Kien; Benahmed, Nadia; Hicher, Pierre-Yves

    2017-06-01

    This paper presents an experimental study of mechanical response of natural Camargue silty sand. The analysis of test results used the equivalent intergranular void ratio instead of the global void ratio. The calculation of equivalent intergranular void ratio requires the determination of parameter b which represents, physically, the fraction of active fines participating on the chain forces network, hence the strength of the soil. A new formula for determining the parameter b by using an approach based on the coordination number distribution and probability calculation is proposed. The validation of the developed relationship was done through back-analysis of published datasets in literature on the effect of fines content on silty sand behavior. It is shown that the equivalent intergranular void ratio calculated with the b value obtained by the new formula is able to provide strong correlation to not only the critical state of but also the onset of instability of various silty sands, in different terms as peak deviator stress, peak stress ratio or cyclic resistance. Therefore, it is suggested that the use of the equivalent void ratio concept and the new b calculating formula is highly desirable in predicting of the silty sand behavior.

  12. Determination of the equivalent intergranular void ratio - Application to the instability and the critical state of silty sand

    Directory of Open Access Journals (Sweden)

    Nguyen Trung-Kien

    2017-01-01

    Full Text Available This paper presents an experimental study of mechanical response of natural Camargue silty sand. The analysis of test results used the equivalent intergranular void ratio instead of the global void ratio. The calculation of equivalent intergranular void ratio requires the determination of parameter b which represents, physically, the fraction of active fines participating on the chain forces network, hence the strength of the soil. A new formula for determining the parameter b by using an approach based on the coordination number distribution and probability calculation is proposed. The validation of the developed relationship was done through back-analysis of published datasets in literature on the effect of fines content on silty sand behavior. It is shown that the equivalent intergranular void ratio calculated with the b value obtained by the new formula is able to provide strong correlation to not only the critical state of but also the onset of instability of various silty sands, in different terms as peak deviator stress, peak stress ratio or cyclic resistance. Therefore, it is suggested that the use of the equivalent void ratio concept and the new b calculating formula is highly desirable in predicting of the silty sand behavior.

  13. Sheath structure and formation of dust voids in cylindrical plasma discharges.

    Science.gov (United States)

    Hu, Zuquan; Chen, Yinhua; Huang, Feng; Shi, Gui-fen; Zheng, Jugao; Yu, M Y

    2010-05-01

    Using a self-consistent two-dimensional fluid model the structure of the plasma sheath in a cylindrical system is investigated. The results show that there is a bumping potential in the central axis resulting in the larger outward directing ion drag force with respect to the opposite electric field force. And the process of the formation of dust voids is studied in the sheath by molecular-dynamics simulation.

  14. Simplifying the diagnosis of 4 common voiding conditions using uroflow/electromyography, electromyography lag time and voiding history.

    Science.gov (United States)

    Van Batavia, Jason P; Combs, Andrew J; Hyun, Grace; Bayer, Agnes; Medina-Kreppein, Daisy; Schlussel, Richard N; Glassberg, Kenneth I

    2011-10-01

    Noninvasive uroflowmetry with simultaneous electromyography is useful to triage cases of lower urinary tract symptoms into 4 urodynamically defined conditions, especially when incorporating short and long electromyography lag times in the analysis. We determined the prevalence of these 4 conditions at a single referral institution and the usefulness of uroflowmetry with simultaneous electromyography and electromyography lag time to confirm the diagnosis, guide treatment and monitor response. We retrospectively reviewed the records of 100 consecutive normal children who presented with persistent lower urinary tract symptoms, underwent uroflowmetry with electromyography as part of the initial evaluation and were diagnosed with 1 of 4 conditions based on certain uroflowmetry/electromyography features. The conditions included 1) dysfunctional voiding--active pelvic floor electromyography during voiding with or without staccato flow, 2a) idiopathic detrusor overactivity disorder-A--a quiet pelvic floor during voiding and shortened lag time (less than 2 seconds), 2b) idiopathic detrusor overactivity disorder-B--a quiet pelvic floor with a normal lag time, 3) detrusor underutilization disorder--volitionally deferred voiding with expanded bladder capacity but a quiet pelvic floor, and 4) primary bladder neck dysfunction--prolonged lag time (greater than 6 seconds) and a depressed, right shifted uroflowmetry curve with a quiet pelvic floor during voiding. Treatment was tailored to the underlying condition in each patient. The group consisted of 50 males and 50 females with a mean age of 8 years (range 3 to 18). Dysfunctional voiding was more common in females (p Electromyography lag time increased in idiopathic detrusor overactivity disorder-A cases and decreased in primary bladder neck dysfunction cases. Noninvasive uroflowmetry with simultaneous electromyography offers an excellent alternative to invasive urodynamics to diagnose 4 urodynamically defined conditions. It

  15. Chemical Imaging and Dynamical Studies of Reactivity and Emergent Behavior in Complex Interfacial Systems. Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Sibener, Steven J. [Univ. of Chicago, IL (United States). James Franck Inst. and Dept. of Chemistry

    2014-03-11

    This research program explored the efficacy of using molecular-level manipulation, imaging and scanning tunneling spectroscopy in conjunction with supersonic molecular beam gas-surface scattering to significantly enhance our understanding of chemical processes occurring on well-characterized interfaces. One program focus was on the spatially-resolved emergent behavior of complex reaction systems as a function of the local geometry and density of adsorbate-substrate systems under reaction conditions. Another focus was on elucidating the emergent electronic and related reactivity characteristics of intentionally constructed single and multicomponent atom- and nanoparticle-based materials. We also examined emergent chirality and self-organization in adsorbed molecular systems where collective interactions between adsorbates and the supporting interface lead to spatial symmetry breaking. In many of these studies we combined the advantages of scanning tunneling (STM) and atomic force (AFM) imaging, scanning tunneling local electronic spectroscopy (STS), and reactive supersonic molecular beams to elucidate precise details of interfacial reactivity that had not been observed by more traditional surface science methods. Using these methods, it was possible to examine, for example, the differential reactivity of molecules adsorbed at different bonding sites in conjunction with how reactivity is modified by the local configuration of nearby adsorbates. At the core of this effort was the goal of significantly extending our understanding of interfacial atomic-scale interactions to create, with intent, molecular assemblies and materials with advanced chemical and physical properties. This ambitious program addressed several key topics in DOE Grand Challenge Science, including emergent chemical and physical properties in condensed phase systems, novel uses of chemical imaging, and the development of advanced reactivity concepts in combustion and catalysis including carbon

  16. Reactive hyperaemia in the calf of trained and untrained subjects: a study with strain gauge plethysmography.

    Science.gov (United States)

    Kroese, A J

    1977-04-01

    Postischaemic reactive hyperaemia in the calf was investigated by strain gauge plethysmography in three pairs of trained and untrained groups of different ages. Maximal flow and repayment in the trained adults were greater than in corresponding untrained groups. This may be due to training effect on the arterioles and a relatively great muscle volume and vascular bed in athletes. The 58-year-old trained men revealed a postischaemic hyperaemic response of approximately the same magnitude as the 25-year-old athletes. Training in old age may result in less degeneration of vascular smooth muscle as well as striated muscle and may induced a relatively great cardiac stroke volume, factors which probably influence reactive hyperaemia in the calf. Hyperaemia in 13-year-old children of different conditions of training was approximwtely the same. It is concluded that the influence of training state on postischaemic calf flow may be considered when reactive hyperaemia is used as a test of the peripheral circulation.

  17. Cytological features of carcinoma of the collecting ducts of Bellini in voided urine cytology.

    Science.gov (United States)

    Ohsaki, Hiroyuki; Hirakawa, Eiichiro; Kushida, Yoshio; Kadota, Kyuichi; Ishikawa, Masashi; Haba, Reiji

    2009-09-01

    Carcinoma of the collecting ducts of Bellini (CCDB) is a rare histological type of renal cell carcinoma. This article describes the cytological features of CCDB in voided urine, confirmed on the basis of the histopathology and immunohistochemistry. The CCDB cells occurred singly in loose aggregates and in small clusters, occasionally in a rosette-like structure. There were various types of cancer cells, including round to oval, spindle, and tadpole-like cells. The nuclei usually showed coarse chromatin, inconspicuous nucleoli, and lacy to vacuolated cytoplasm. CCDB of the kidney is a rare cytodiagnostic challenge in voided urine cytology alone. When the cytological diagnosis is considered, it is necessary to perform immunocytochemistry and correlate the clinical history and imaging studies. 2009 Wiley-Liss, Inc.

  18. Intraspinal stimulation for bladder voiding in cats before and after chronic spinal cord injury

    Science.gov (United States)

    Pikov, Victor; Bullara, Leo; McCreery, Douglas B.

    2007-12-01

    The long-term objective of this study is to develop neural prostheses for people with spinal cord injuries who are unable to voluntarily control their bladder. This feasibility study was performed in 22 adult cats. We implanted an array of microelectrodes into locations in the sacral spinal cord that are involved in the control of micturition reflexes. The effect of microelectrode stimulation was studied under light Propofol anesthesia at monthly intervals for up to 14 months. We found that electrical stimulation in the sacral parasympathetic nucleus at S2 level or in adjacent ventrolateral white matter produced bladder contractions insufficient for inducing voiding, while stimulation at or immediately dorsal to the dorsal gray commissure at S1 level produced strong (at least 20 mmHg) bladder contractions as well as strong (at least 40 mm Hg) external urethral sphincter relaxation, resulting in bladder voiding in 14 animals. In a subset of three animals, spinal cord transection was performed. For several months after the transection, intraspinal stimulation continued to be similarly or even more effective in inducing the bladder voiding as before the transection. We speculate that in the absence of the supraspinal connections, the plasticity in the local spinal circuitry played a role in the improved responsiveness to intraspinal stimulation.

  19. Contrast-enhanced Voiding Urosonography for Vesicoureteral Reflux Diagnosis in Children.

    Science.gov (United States)

    Duran, Carmina; Beltrán, Viviana P; González, Amàlia; Gómez, Carles; Riego, Javier Del

    2017-10-01

    Contrast-enhanced voiding urosonography (ceVUS) is a dynamic imaging technique that makes it possible to study the structure of the urinary tract after the administration of intravesical contrast material. Initially, ceVUS was indicated mainly to study vesicoureteral reflux (VUR); however, since the ability of ceVUS to depict the structure of the urethra was demonstrated in both sexes, ceVUS is now indicated for examination of the entire urinary tract. The main benefit of ceVUS is that it does not use ionizing radiation. In recent years, fundamental changes have occurred in the understanding of VUR. The lessening effect of VUR and the low rate of occurrence of urethral pathologic conditions have given rise to changes in the indications for tests for these conditions. In addition to being able to help confirm a diagnosis of VUR, the ceVUS technique can be used to depict obstructive and nonobstructive urethral pathologic conditions, as well as normal variants, on high-quality images. Furthermore, ceVUS enables real-time assessment of voiding function. For these reasons, ceVUS should be not only an alternative to voiding cystourethrography, but also the technique of choice for the study of the entire urinary tract in pediatric patients. Online supplemental material is available for this article. ©RSNA, 2017.

  20. A mesocosm study of oxygen and trace metal dynamics in sediment microniches of reactive organic material

    DEFF Research Database (Denmark)

    Letho, Niklas; Larsen, Morten; Zhang, Hao

    2017-01-01

    simultaneous measurements of dissolved O2 and trace metal dynamics around an aggregate of reactive organic matter placed on the SWI of a sediment mesocosm. The aggregate induced a rapid, highly localized, decrease in O2 concentration, resulting in an anoxic feature at the SWI. Co-located with this feature, we...... mobilization at the SWI. By using a combined planar optode-DGT (diffusive gradient in thin-films) sensor we obtained simultaneous measurements of dissolved O2 and trace metal dynamics around an aggregate of reactive organic matter placed on the SWI of a sediment mesocosm. The aggregate induced a rapid, highly...

  1. Electric field theory and the fallacy of void capacitance

    DEFF Research Database (Denmark)

    McAllister, Iain Wilson

    1991-01-01

    The concept of the capacitance of a gaseous void is discussed as applied to electrical insulation science. The most pertinent aspect of the capacitance definition is that of reference to a single-valued potential difference between surfaces. This implies that these surfaces must be surfaces...

  2. Efficacy of voided urinary cytology and ultrasonography compared to ...

    African Journals Online (AJOL)

    N. Kumar

    2017-07-29

    Jul 29, 2017 ... of bladder cancer was done. They were subjected to voided urinary cytology and ultrasonography. The results were compared with the inferences drawn from cystoscopy and histopathological examination of the resected tumor, wherever applicable. Results: The sensitivity of urinary cytology and ...

  3. Low-void polyimide resins for autoclave processing

    Science.gov (United States)

    Jones, R. J.; Vaughan, R. W.

    1972-01-01

    Development of an advanced A-type polyimide, which can be used to produce autoclave molded, low-void content composites suitable for use at temperatures up to 316 C is reported. It consists of a mixture of methyl nadic anhydride, an 80:20 molar ratio of methylene dianaline and thiodianilene, and pyromellitic dianhydride.

  4. Calculation of Void in the Fort Saint Vrain Material

    Energy Technology Data Exchange (ETDEWEB)

    Potter, David Charles [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Taylor, Craig Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Coons, James Elmer [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-05-11

    The percent void of the Fort Saint Vrain (FSV) material is estimated to be 21.1% based on the volume of the gap at the top of the drums, the volume of the coolant channels in the FSV fuel element, and the volume of the fuel handling channel in the FSV fuel element.

  5. Efficacy of voided urinary cytology and ultrasonography compared to ...

    African Journals Online (AJOL)

    Introduction: Painless hematuria is the presenting symptom in 85–90% of patients with bladder cancer. Objectives: To evaluate the efficacy of voided urinary cytology and ultrasonography in the diagnosis and follow up of bladder cancer compared to cystoscopy as a gold standard with reference to its grade. To recommend a ...

  6. a Study of Reactive Quenching of Xenon by Chlorides Using Two-Photon Laser Excitation

    Science.gov (United States)

    Bruce, Michael Richard

    1990-01-01

    State-selective two-photon laser excitation is utilized to study inelastic energy transfer in rare gas halide reactions. These studies have helped to understand the energy pathways and reaction processes important to the physics of the excimer laser. Moreover, they have lead to a better fundamental understanding of electronic energy transfer. In particular, reactions of Xe (5p ^5np, np^' n = 6,7) with chlorine molecules are studied. The observed quench rates were surprisingly large; experimental cross sections extended from 400A^2 to 1000A^2. Previous models for the excimer laser used only reaction cross sections of 200A ^2 for the lowest excited states of xenon (5p^56s); they neglected all more highly excited states. Nevertheless, it was shown that the large reactions rates are consistent with current theory; the reaction Rg^{*} + Cl_2 is vibronically coupled onto the Rg^{+} + Cl _sp{2}{-} ionic surface by means of the Cl_2 molecular vibrations. In addition, the neutral termolecular reactive collisions, Rg^{*} + Cl _2 + Rg to RgCl^{*} + Cl + Rg, were observed. The large rates (~10 ^{-28}cm^6 /sec) were understood by means of an orbiting collision complex model; the role of the third body (Rg) was not to take up excess thermal energy as had been assumed in previous calculations, but to enhance the probability for charge transfer between the two neutral species (Rg ^{*} and Cl_2) by altering the effective ionization limit. This process could be important in any high density neutral reaction that proceeds through an ionic intermediary. These results have shown that termolecular reactions are universal to many forms of energy transfer reactions; furthermore, we can no longer hope to understand chemistry at high pressures by a study of binary reactions at low pressures. Also, quenching measurements in pure rare gases were studied. Bimolecular reaction rates were determined for Xe (5p^5np, np^ ' n = 6,7) in xenon and argon buffer gases. In general, the quenching rates

  7. Metabolic syndrome: prevalence, associated factors, and C-reactive protein: the MADRIC (MADrid RIesgo Cardiovascular) Study.

    Science.gov (United States)

    Martínez, Maria A; Puig, Juan G; Mora, Marta; Aragón, Rosa; O'Dogherty, Pascual; Antón, José L; Sánchez-Villares, Teresa; Rubio, José M; Rosado, Javier; Torres, Rosa; Marcos, Joaquín; Pallardo, Luis F; Banegas, José R

    2008-09-01

    The metabolic syndrome (MS) is defined by the clustering of a number of cardiovascular risk factors. The aims of the present study were to estimate the prevalence of MS in Madrid (Spain) by 2 definitions and to investigate its relationship with several sociodemographic factors and C-reactive protein (CRP) levels. This was a cross-sectional population study, and participants were 1344 subjects aged 31 to 70 years. Clinical evaluation included data on sociodemographic and cardiovascular background, physical examination, fasting glucose, triglycerides, and high-density lipoprotein cholesterol. The CRP levels were determined in a subgroup of 843 subjects. The diagnosis of MS was made according to the 2005 Adult Treatment Panel III (ATP III) and International Diabetes Federation (IDF) definitions. The age- and sex-adjusted prevalence of MS was 24.6% (95% confidence interval [CI], 22.3%-26.9%) using the ATP III definition and 30.9% (95% CI, 28.4%-33.3%) using the International Diabetes Federation definition. The overall agreement rate was 91.5% (kappa = 0.80; 95% CI, 0.76-0.83). Prevalence figures by both definitions were higher in men than in women and increased with age. Male sex, older age, low educational level, and physical inactivity were all determinants of ATP III-defined MS. The presence of MS or any of its components was associated with high CRP levels. In a logistic regression analysis, low educational level and waist circumference were the best predictors for high CRP level. The prevalence of MS in the Madrid region is one of the highest in Europe and confirms the strong Spanish regional variability in this syndrome frequency. Some sociodemographic and lifestyle factors, particularly educational level, are predictors for MS and high CRP levels.

  8. Exploratory Cohort Study of Associations between Serum C - Reactive Protein and Fatigue after Stroke.

    Directory of Open Access Journals (Sweden)

    Simiao Wu

    Full Text Available Post-stroke fatigue is a common and distressing problem but little is known about its biological mechanisms. This cohort study was to investigate associations between C-reactive protein (CRP and fatigue after stroke.Patients were assessed at one, six and 12 months after their stroke onset, with the Fatigue Assessment Scale, a case definition of post-stroke fatigue, Hospital Anxiety and Depression Scale, and daily step counts. Blood samples were collected at each assessment and the CRP level was determined by a standard CRP immunoassay. Cross-sectional associations between CRP and fatigue at each time point were determined by Pearson correlation coefficient and independent-samples t-test. Whether CRP levels at one month predict fatigue scores at six and 12 months was explored by multiple linear regression, with anxiety, depression, and daily step counts as covariates.Sixty-five patients (mean age 67 years, 65% men were included: 61 at one month, 49 at six months, and 41 at 12 months. CRP levels and fatigue scores were not associated at one month (p = 0.88 or 12 months (p = 0.56, but weakly associated at six months (r = 0.27, p = 0.04; however, this association was no longer significant (p = 0.14 after controlling for the effects of covariates. The CRP level was not associated with the fulfilment of case definition of post-stroke fatigue at any time points (all p > 0.05. The CRP level at one month was not a significant predictor for fatigue levels at either six months (p = 0.93 or 12 months (p = 0.78.There is insufficient evidence for the association between CRP and PSF in stroke patients. Future studies with larger sample sizes and controlling for potential confounders are needed to investigate whether this association exists.

  9. Interleukin-6 and C-reactive protein, successful aging, and mortality: the PolSenior study.

    Science.gov (United States)

    Puzianowska-Kuźnicka, Monika; Owczarz, Magdalena; Wieczorowska-Tobis, Katarzyna; Nadrowski, Pawel; Chudek, Jerzy; Slusarczyk, Przemyslaw; Skalska, Anna; Jonas, Marta; Franek, Edward; Mossakowska, Malgorzata

    2016-01-01

    In the elderly, chronic low-grade inflammation (inflammaging) is a risk factor for the development of aging-related diseases and frailty. Using data from several thousand Eastern Europeans aged 65 years and older, we investigated whether the serum levels of two proinflammatory factors, interleukin-6 (IL-6) and C-reactive protein (CRP), were associated with physical and cognitive performance, and could predict mortality in successfully aging elderly. IL-6 and CRP levels systematically increased in an age-dependent manner in the entire study group (IL-6: n = 3496 individuals, p successfully aging individuals who had never been diagnosed with cardiovascular disease, myocardial infarction, stroke, type 2 diabetes, or cancer, and had a Mini Mental State Examination (MMSE) score ≥24 and a Katz Activities of Daily Living (ADL) score ≥5 (IL-6: n = 1258, p aging-related diseases/disability, only IL-6 increased with age (IL-6: n = 2238, p successfully aging individuals than in the remaining study participants (both p age, gender, BMI, lipids, estimated glomerular filtration rate, and smoking status. Longer survival was associated with lower concentrations of IL-6 and CRP not only in individuals with aging-related diseases/disability (HR = 1.063 per each pg/mL, 95 % CI: 1.052-1.074, p successfully aging subgroup (HR = 1.163 per each pg/mL, 95 % CI: 1.128-1.199, p age, gender, BMI, lipids and smoking status. The Kaplan-Meier survival curves showed similar results (all p successfully aging individuals.

  10. Impact of benign prostatic hyperplasia surgical treatment on voiding and urinary bladder filling symptoms

    Directory of Open Access Journals (Sweden)

    Milićević Snježana

    2010-01-01

    Full Text Available Background/Aim. Benign prostatic hyperplasia (BHP is one of the most common diseases of elderly men. The aim of this study was to evaluate the effect of surgical treatment of benign prostatic hyperplasia to voiding and urinary bladder filling symptoms. Quantification of voiding and filling symptoms was done with the International Prostate Symptom Score (IPSS. Method. The study included 80 patients with BHP, of whom 40 were treated with open prostatectomy (group A, and other 40 with transurethral resection of prostate gland (group B. All the patients were under 80 years old (average age in the group A was 70.23 years with a variation interval of 21 years, and in the group B 69.37 years with a variation interval of 22 years, with a value of IPSS > 19 points, quantity of residual urine higher than 150 mL, the weight of benign prostatic gland hyperplasia tissue over 30 grams for the method of prostate transurethral resection, and over 80 grams for the method of open prostatectomy. To all patients, for two times, the value of IPSS was determined, and then in a postoperative period in time intervals of 4 and 12 weeks. Results. Arithmetic mean of IPSS preoperatively was 32.05 points in the group A and 31.75 points in the group B. During the postoperative check-ups in time intervals of 4 and 12 weeks, arithmetic means of IPSS in the group A were 5.4 and 1.85 points, respectively, and in the group B 11.425 and 9.025 points, respectively. Surgical treatment had better effect on voiding symptoms than on urinary bladder filling ones. Conclusion. After the mentioned surgical procedures a significant reduction of the lower urinary tract symptoms quantified by the IPSS was observed. Surgical treatment of BHP had a more pronounced effect on the voiding symptoms in relation to filling ones.

  11. Void coalescence mechanism for combined tension and large amplitude cyclic shearing

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau; Andersen, Rasmus Grau; Tvergaard, Viggo

    2017-01-01

    , imposed at the far boundary, is in an early state of the deformation associated with significant stretching of parts of the void surface, while other parts remain practically un-deformed. A largely uneven distribution of the strain hardening, therefore, evolves along the void circumference and, thus, one...... cannot expect the void to return to its original shape in the case where the far-field loading is reversed. The present numerical work aims to investigate the evolution of micro-voids subject to constant tension and large amplitude cyclic shearing. The far-field loading, the void shape, and the void...

  12. Discrete modelling of ductile crack growth by void growth to coalescence

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2007-01-01

    Ductile crack growth is analyzed by discrete representation of the voids growing near a blunting crack-tip. Coalescence of the nearest void with the crack-tip is modeled, followed by the subsequent coalescence of other discretely represented voids with the newly formed crack-tip. Necking of the l......Ductile crack growth is analyzed by discrete representation of the voids growing near a blunting crack-tip. Coalescence of the nearest void with the crack-tip is modeled, followed by the subsequent coalescence of other discretely represented voids with the newly formed crack-tip. Necking...

  13. Differences in urodynamic voiding variables recorded by conventional cystometry and ambulatory monitoring in symptomatic women

    Directory of Open Access Journals (Sweden)

    Juan Pablo Valdevenito

    2014-10-01

    Full Text Available Objectives To determine whether there are differences in pressure and flow measurements between conventional cystometry (CONV and ambulatory urodynamic monitoring (AMB in women with overactive bladder syndrome and urinary incontinence. Materials and Methods Retrospective study which included female subjects who underwent both CONV (with saline filling medium and AMB, separated by less than 24 months, not using medication active on the lower urinary tract and without history of prior pelvic surgery. Both tests were carried out in compliance with the International Continence Society standards. The paired Student’s t test was used to compare continuous variables. Bland-Altman statistics were used to assess the agreement of each variable between both studies. Results Thirty women with a median (range age of 50 (14 - 73 years met the inclusion criteria. AMB was carried out at a mean (SD of 11 (6 months after CONV. Measurements of pves and pabd at the end of filling, and Qmax were significantly higher from AMB recordings. There were no differences in pdet at the end of filling, pdetQmax or pdetmax during voiding, nor significant difference in Vvoid. Conclusions We provide previously undocumented comparative voiding data between CONV and AMB for patients who most commonly require both investigations. Our findings show higher values of Qmax but similar values of pdetQmax measured by AMB which may partly reflect an overall lower catheter caliber, physiological filling but perhaps also more ‘normal’ voiding conditions.

  14. Nucleation and void formation mechanisms in SiC thin film growth on Si by carbonization

    Energy Technology Data Exchange (ETDEWEB)

    Li, J.P.; Steckl, A.J. [Univ. of Cincinnati, OH (United States)

    1995-02-01

    The nucleation mechanisms for SiC thin films on Si were investigated by interrupting the growth at very brief times ({approximately}1 to 10 s) using rapid thermal chemical vapor deposition in conjunction with hydrocarbon carbonization. The resulting SiC nuclei and films on Si have been studied by scanning electron microscopy and atomic force microscopy. The hydrocarbon partial pressure in the gas stream was found to determine the nucleation mode. Low precursor concentration results in initial three-dimensional (island) growth which enables the study or trench and void formation. Voids were observed to initiate when two neighboring nuclei come in contact. Trenches in the Si substrate surround each isolated nucleus, with the trench depth increasing with the diameter of the island. SiC films grown for a nominal reaction time of 1 s indicate that increasing the propane concentration results in decreases in SiC grain size and surface roughness and an increase in the nuclei density. A model is proposed for the nucleation process of SiC growth on Si by carbonization consisting of the following key steps: (1) the initial nucleation density is determined by the precursor concentration; (2) lateral and vertical growth of individual nuclei proceeds by consumption of Si atoms around their periphery, forming trenches in the substrate; (3) Si voids are formed in the Si substrate near the SiC/Si interface when nuclei grow large enough to come in contact and, thus, restrict the supply of Si atoms.

  15. NUMERICAL ANALYSIS OF FLAT SLABS WITH SPHERICAL VOIDS SUBJECTED TO SHEAR FORCE

    Directory of Open Access Journals (Sweden)

    Bindea M.

    2015-05-01

    Full Text Available Full flat slabs can be enhanced by using spherical voids to replace the unemployed concrete from the core part of the slab. Therefore we get low self-weighted slabs that can reach a high range of spans, a low material consumption compared to classical solutions used so far. On the other hand, the upsides of these slabs pale against the insecurity in design stage about their punching and shear force behaviour. In this paper it is presented a parametric study about shear force behaviour of flat slabs with spherical voids used in standard condition service. The study was made using the Atena 3D finit element design software, starting form a numerical model gauged on experimental results on real models – scale 1:1. Based on these lab results, the model’s validation was made by overlapping the load – displacement experimental curves on the curves yielded from numerical analyses. The results indicate that under a longitudinal reinforcement rate of lower than 0.50%, flat slabs with spherical voids don’t fail to shear force and over this value the capable shear force decreases in comparison with solid slabs, as the reinforcement rate increases.

  16. Impact of the Type and Number of Composite Layers in Flexural Strengthening of Reinforced Concrete Voided Slabs with FRP Using Finite Element Method

    National Research Council Canada - National Science Library

    Muhammed Maleknia; Ataollah Hajati Modaraei

    2016-01-01

    .... One usage of FRP laminates is strengthening the reinforced concrete slabs. Present article studied the impact of type and number of composite layers in flexural strengthening of the reinforced concrete voided slabs with FRP laminates...

  17. Characterization of voids formed during liquid impregnation of nonwoven multifilament glass networks as related to composite processing

    Science.gov (United States)

    Mahale, Anant D.; Prudhomme, Robert K.; Rebenfeld, Ludwig

    1993-01-01

    A technique based on matching the refractive index of an invading liquid to that of a fiber mat was used to study entrapment of air ('voids') that occurs during forced in-plane radial flow into nonwoven multifilament glass networks. The usefulness of this technique is demonstrated in quantifying and mapping the air pockets. Experiments with a series of fluids with surface tensions varying from 28 x 10(exp -3) to 36 x 10(exp -3) N/m, viscosities from 45 x 10(exp -3) to 290 x 10(exp -3) Pa.s, and inlet flow rates from 0.15 x 10(exp -6) to 0.75 x 10(exp -6) m(exp 3)/s, showed that void content is a function of the capillary number characterizing the flow process. A critical value of capillary number, Ca = 2.5 x 10(exp -3), identifies a zone below which void content increases exponentially with decreasing capillary number. Above this critical value, negligible entrapment of voids is observed. Similar experiments carried out on surface treated nonwoven mats spanning a range of equilibrium contact angles from 20 deg to 78 deg showed that there is a critical contact angle above which negligible entrapment is observed. Below this value, there is no apparent effect of contact angle on the void fraction - capillary number relationship described earlier. Studies on the effect of filament wettability, and fluid velocity and viscosity on the size of the entrapment (voids) were also carried out. These indicate that larger sized entrapments which envelop more than one pore are favored by a low capillary number in comparison to smaller, pore level bubbles. Experiments were carried out on deformed mats - imposing high permeability spots at regular intervals on a background of low permeability. The effect of these spatial fluctuations in heterogeneity of the mat on entrapment is currently being studied.

  18. Constraints on Cosmology and Gravity from the Dynamics of Voids.

    Science.gov (United States)

    Hamaus, Nico; Pisani, Alice; Sutter, P M; Lavaux, Guilhem; Escoffier, Stéphanie; Wandelt, Benjamin D; Weller, Jochen

    2016-08-26

    The Universe is mostly composed of large and relatively empty domains known as cosmic voids, whereas its matter content is predominantly distributed along their boundaries. The remaining material inside them, either dark or luminous matter, is attracted to these boundaries and causes voids to expand faster and to grow emptier over time. Using the distribution of galaxies centered on voids identified in the Sloan Digital Sky Survey and adopting minimal assumptions on the statistical motion of these galaxies, we constrain the average matter content Ω_{m}=0.281±0.031 in the Universe today, as well as the linear growth rate of structure f/b=0.417±0.089 at median redshift z[over ¯]=0.57, where b is the galaxy bias (68% C.L.). These values originate from a percent-level measurement of the anisotropic distortion in the void-galaxy cross-correlation function, ϵ=1.003±0.012, and are robust to consistency tests with bootstraps of the data and simulated mock catalogs within an additional systematic uncertainty of half that size. They surpass (and are complementary to) existing constraints by unlocking cosmological information on smaller scales through an accurate model of nonlinear clustering and dynamics in void environments. As such, our analysis furnishes a powerful probe of deviations from Einstein's general relativity in the low-density regime which has largely remained untested so far. We find no evidence for such deviations in the data at hand.

  19. On the linearity of tracer bias around voids

    Science.gov (United States)

    Pollina, Giorgia; Hamaus, Nico; Dolag, Klaus; Weller, Jochen; Baldi, Marco; Moscardini, Lauro

    2017-07-01

    The large-scale structure of the Universe can be observed only via luminous tracers of the dark matter. However, the clustering statistics of tracers are biased and depend on various properties, such as their host-halo mass and assembly history. On very large scales, this tracer bias results in a constant offset in the clustering amplitude, known as linear bias. Towards smaller non-linear scales, this is no longer the case and tracer bias becomes a complicated function of scale and time. We focus on tracer bias centred on cosmic voids, i.e. depressions of the density field that spatially dominate the Universe. We consider three types of tracers: galaxies, galaxy clusters and active galactic nuclei, extracted from the hydrodynamical simulation Magneticum Pathfinder. In contrast to common clustering statistics that focus on auto-correlations of tracers, we find that void-tracer cross-correlations are successfully described by a linear bias relation. The tracer-density profile of voids can thus be related to their matter-density profile by a single number. We show that it coincides with the linear tracer bias extracted from the large-scale auto-correlation function and expectations from theory, if sufficiently large voids are considered. For smaller voids we observe a shift towards higher values. This has important consequences on cosmological parameter inference, as the problem of unknown tracer bias is alleviated up to a constant number. The smallest scales in existing data sets become accessible to simpler models, providing numerous modes of the density field that have been disregarded so far, but may help to further reduce statistical errors in constraining cosmology.

  20. Does high C-reactive protein concentration increase atherosclerosis? The Whitehall II Study.

    Directory of Open Access Journals (Sweden)

    Mika Kivimäki

    Full Text Available BACKGROUND: C-reactive protein (CRP, a marker of systemic inflammation, is associated with risk of coronary events and sub-clinical measures of atherosclerosis. Evidence in support of this link being causal would include an association robust to adjustments for confounders (multivariable standard regression analysis and the association of CRP gene polymorphisms with atherosclerosis (Mendelian randomization analysis. METHODOLOGY/PRINCIPAL FINDINGS: We genotyped 3 tag single nucleotide polymorphisms (SNPs [+1444T>C (rs1130864; +2303G>A (rs1205 and +4899T>G (rs 3093077] in the CRP gene and assessed CRP and carotid intima-media thickness (CIMT, a structural marker of atherosclerosis, in 4941 men and women aged 50-74 (mean 61 years (the Whitehall II Study. The 4 major haplotypes from the SNPs were consistently associated with CRP level, but not with other risk factors that might confound the association between CRP and CIMT. CRP, assessed both at mean age 49 and at mean age 61, was associated both with CIMT in age and sex adjusted standard regression analyses and with potential confounding factors. However, the association of CRP with CIMT attenuated to the null with adjustment for confounding factors in both prospective and cross-sectional analyses. When examined using genetic variants as the instrument for serum CRP, there was no inferred association between CRP and CIMT. CONCLUSIONS/SIGNIFICANCE: Both multivariable standard regression analysis and Mendelian randomization analysis suggest that the association of CRP with carotid atheroma indexed by CIMT may not be causal.

  1. Impaired neural reward processing in children and adolescents with reactive attachment disorder: A pilot study.

    Science.gov (United States)

    Mizuno, Kei; Takiguchi, Shinichiro; Yamazaki, Mika; Asano, Mizuki; Kato, Shiho; Kuriyama, Kikuko; Watanabe, Yasuyoshi; Sadato, Norihiro; Tomoda, Akemi

    2015-10-01

    Reactive attachment disorder (RAD) is characterized by markedly disturbed and developmentally inappropriate social relatedness due to parental maltreatment. RAD patients often display a high number of comorbid attention deficit/hyperactivity disorder (ADHD) symptoms, and certain RAD symptoms are difficult to discriminate from ADHD. One of the core characteristics of ADHD is a decrease in neural reward processing due to dopamine dysfunction. The aim of the present study was to determine whether the brain activity involved in reward processing in RAD patients is impaired in comparison with ADHD patients and typically developed controls. Five RAD patients, 17 typically developed (TD) controls and 17 ADHD patients aged 10-16 years performed tasks with high and low monetary reward while undergoing functional magnetic resonance imaging. ADHD patients were tested before and after 3 months treatment with osmotic release oral system-methylphenidate. Before treatment, ADHD patients showed that striatal and thalamus activities only in the tasks with low monetary reward were lower than TD controls. RAD patients showed decrease in activity of the caudate, putamen and thalamus during both the high and low monetary reward conditions in comparison with all the other groups. In RAD patients, the activity of the putamen was associated with the severity of posttraumatic stress and overt dissociation. Reward sensitivity was markedly decreased in children and adolescents with RAD, as evidenced by a diminished neural response during reward perception. This suggests that dopaminergic dysfunction exists in these patients, and may inform future dopaminergic treatment strategies for RAD. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Modeling Of A Reactive Distillation Column: Methyl Tertiary Butyl Ether (Mtbe Simulation Studies

    Directory of Open Access Journals (Sweden)

    Ismail Mohd Saaid Abdul Rahman Mohamed and Subhash Bhatia

    2012-10-01

    Full Text Available A process simulation stage-wise reactive distillation column model formulated from equilibrium stage theory was developed. The algorithm for solving mathematical model represented by sets of differential-algebraic equations was based on relaxation method. Numerical integration scheme based on backward differentiation formula was selected for solving the stiffness of differential-algebraic equations. Simulations were performed on a personal computer (PC Pentium processor through a developed computer program using FORTRAN90 programming language. The proposed model was validated by comparing the simulated results with the published simulation results and with the pilot plant data from the literature. The model was capable of predicting high isobutene conversion for heterogeneous system, as desirable in industrial MTBE production process. The comparisons on temperature profiles, liquid composition profile and operating conditions of reactive distillation column also showed promising results. Therefore the proposed model can be used as a tool for the development and simulation of reactive distillation column.Keywords: Modeling, simulation, reactive distillation, relaxation method, equilibrium stage, heterogeneous, MTBE

  3. Hypothalamic-pituitary-adrenal axis reactivity to social stress and adolescent cannabis use : the TRAILS study

    NARCIS (Netherlands)

    van Leeuwen, Andrea Prince; Creemers, Hanneke E.; Greaves-Lord, Kirstin; Verhulst, Frank C.; Ormel, Johan; Huizink, Anja C.

    Aims To investigate the relationship of life-time and repeated cannabis use with hypothalamic-pituitary-adrenal (HPA) axis reactivity to social stress in a general population sample of adolescents. Design Adolescents who reported life-time or repeated cannabis use, life-time or repeated tobacco use

  4. Study of atomic and condensed atomic indices for reactive sites of ...

    Indian Academy of Sciences (India)

    In this paper, we have introduced the atomic descriptors () to determine the local reactive sites of the molecular systems during electrophilic, nucleophilic and radical attacks. The condensed Fukui function and the newly introduced condensed atomic descriptor have been calculated for six different systems, namely ...

  5. Study of the cross-reactivity of fish allergens based on a questionnaire and blood testing

    Directory of Open Access Journals (Sweden)

    Yukihiro Kobayashi

    2016-07-01

    Conclusions: Most patients with fish allergies displayed allergic symptoms following the intake of various fish species. In addition, fish parvalbumin and collagen were causative factors of fish allergy and were highly cross-reactive fish panallergens. Therefore, current laws should be revised in Japan and South Korea.

  6. Hypothalamic-pituitary-adrenal axis reactivity to social stress and adolescent cannabis use: the TRAILS study

    NARCIS (Netherlands)

    Prince van Leeuwen, A.; Creemers, H.E.; Greaves-Lord, K.; Verhulst, F.C.; Ormel, J.; Huizink, A.C.

    2011-01-01

    Aims: To investigate the relationship of life-time and repeated cannabis use with hypothalamic-pituitary-adrenal (HPA) axis reactivity to social stress in a general population sample of adolescents. Design: Adolescents who reported life-time or repeated cannabis use, life-time or repeated tobacco

  7. Chocolate or orange juice for non-reactive non-stress test (NST) patterns: a randomized prospective controlled study.

    Science.gov (United States)

    Esin, Sertac; Baser, Eralp; Cakir, Caner; Ustun Tuncal, Gul Nihal; Kucukozkan, Tuncay

    2013-06-01

    The objective of the study was to compare bitter chocolate and orange juice with the control group for non-reactive non-stress test (NST) patterns and for maternal perception of fetal movements. Pregnant women who were followed-up on an outpatient basis and admitted for a NST and had a non-reactive result were randomized prospectively into bitter chocolate, orange juice and control groups. 180 patients were evaluable for the final analysis. Although there was a trend for orange juice group for having higher percentages of reactive NST patterns on control, there was no statistically significant difference between three groups (p = 0.159). Besides this, maternal perception of increased fetal movements was similar between groups (p = 0.755). The control group had lower post-test capillary blood glucose concentrations when compared with chocolate and orange juice groups (p = 0.01) and after post-hoc tests, this difference was found to be between orange juice and control groups. Although orange juice resulted in higher blood glucose levels, this was not synonymous with better NST results on control; in such a way that bitter chocolate, orange juice and no intervention had similar effects on non-reactive NST patterns and also on maternal perception of fetal movements.

  8. Coagulation-adsorption of reactive orange from aqueous solution by freshly formed magnesium hydroxide: mixing time and mechanistic study.

    Science.gov (United States)

    Zhao, Jianhai; Shi, Huanhuan; Liu, Meile; Lu, Jingfang; Li, Wenpu

    2017-04-01

    The utilization of magnesium hydroxide was successfully carried out to remove reactive orange by coagulation-adsorption from aqueous solution. The coagulation-adsorption mechanisms and magnesium hydroxide-reactive orange floc property were analyzed through zeta potential, scanning electron microscope (SEM), X-ray diffraction and Fourier transform infrared spectroscopy (FT-IR). Flocculation Index was then discussed with controlled experiments using intelligent Particle Dispersion Analyzer (iPDA) and optimum rapid mixing time of 90 s was obtained for pH 12. The results of this study indicate that charge neutralization and adsorption are proposed to be the main coagulation mechanisms. The FT-IR spectra and SEM showed that reactive orange was adsorbed on the magnesium hydroxide surface during coagulation and adsorption. Freshly generated magnesium hydroxide can effectively remove reactive orange and the removal efficiency can reach 96.7% and 46.3% for coagulation and adsorption, respectively. Adsorption process accounts for 48% of the whole coagulation experiment. The removal efficiency decreased significantly with increasing magnesium hydroxide formation time.

  9. Novel synthetic approach, spectroscopic characterization and theoretical studies on global and local reactive properties of a bibenzimidazolyl derivative

    Science.gov (United States)

    Prasad, Kollur Shiva; Nayak, Nagaraj; Pillai, Renjith Raveendran; Armaković, Stevan; Armaković, Sanja J.

    2017-11-01

    Benzimidazole derivatives are of interest because they can exhibit multi-drug like properties and thus finds wide applications in biomedicine. Present work describes a novel route for the synthesis of a benzimidazole derivative, 1,7‧-Dimethyl-2‧-propyl-1H,3‧H-[2,5‧]bibenzoimidazolyl (R4) by using dibutyltin dilaurate (DBTDL) as catalyst. The catalyst, DBTDL is commercial and environmentally benign. The molecular structure of R4 was confirmed by FT-IR, 1H, 13C NMR, and mass spectrometry techniques. The detailed reactivity study of R4 encompasses spectroscopic characterization and computational investigations of global and local reactive properties based on the density functional theory (DFT) and time dependent density functional theory (TD-DFT) calculations, and molecular dynamics (MD) and molecular docking (MDoc) simulations. Global reactive properties of the title compound have been investigated by the analysis of frontier molecular orbitals. Local reactive properties have been investigated by the analysis of quantum-molecular descriptors such as molecular electrostatic potential (MEP), average local ionization energy (ALIE) surfaces, and Fukui functions. Bond dissociation energies (BDE) have been calculated in order to determine molecule sites that could be sensitive towards the autoxidation mechanism, while the radial distribution functions have been calculated in order to determine atoms with the significant interactions with water molecules.

  10. Effects of Lateral Funiculus Sparing, Spinal Lesion Level, and Gender on Recovery of Bladder Voiding Reflexes and Hematuria in Rats

    Science.gov (United States)

    Ferrero, Sunny L.; Brady, Tiffany D.; Dugan, Victoria P.; Armstrong, James E.; Hubscher, Charles H.

    2015-01-01

    Abstract Deficits in bladder function are complications following spinal cord injury (SCI), severely affecting quality of life. Normal voiding function requires coordinated contraction of bladder and urethral sphincter muscles dependent upon intact lumbosacral reflex arcs and integration of descending and ascending spinal pathways. We previously reported, in electrophysiological recordings, that segmental reflex circuit neurons in anesthetized male rats were modulated by a bilateral spino-bulbo-spinal pathway in the mid-thoracic lateral funiculus. In the present study, behavioral measures of bladder voiding reflexes and hematuria (hemorrhagic cystitis) were obtained to assess the correlation of plasticity-dependent recovery to the degree of lateral funiculus sparing and mid-thoracic lesion level. Adult rats received mid-thoracic-level lesions at one of the following severities: complete spinal transection; bilateral dorsal column lesion; unilateral hemisection; bilateral dorsal hemisection; a bilateral lesion of the lateral funiculi and dorsal columns; or a severe contusion. Voiding function and hematuria were evaluated by determining whether the bladder was areflexic (requiring manual expression, i.e., “crede maneuver”), reflexive (voiding initiated by perineal stroking), or “automatic” (spontaneous voiding without caretaker assistance). Rats with one or both lateral funiculi spared (i.e., bilateral dorsal column lesion or unilateral hemisection) recovered significantly faster than animals with bilateral lateral funiculus lesions, severe contusion, or complete transection. Bladder reflex recovery time was significantly slower the closer a transection lesion was to T10, suggesting that proximity to the segmental sensory and sympathetic innervation of the upper urinary tract (kidney, ureter) should be avoided in the choice of lesion level for SCI studies of micturition pathways. In addition, hematuria duration was significantly longer in males, compared to

  11. An Optimal Cure Process to Minimize Residual Void and Optical Birefringence for a LED Silicone Encapsulant

    Directory of Open Access Journals (Sweden)

    Min-Jae Song

    2014-05-01

    Full Text Available Silicone resin has recently attracted great attention as a high-power Light Emitting Diode (LED encapsulant material due to its good thermal stability and optical properties. In general, the abrupt curing reaction of the silicone resin for the LED encapsulant during the curing process induces reduction in the mechanical and optical properties of the LED product due to the generation of residual void and moisture, birefringence, and residual stress in the final formation. In order to prevent such an abrupt curing reaction, the reduction of residual void and birefringence of the silicone resin was observed through experimentation by introducing the multi-step cure processes, while the residual stress was calculated by conducting finite element analysis that coupled the heat of cure reaction and cure shrinkage. The results of experiment and analysis showed that it was during the three-step curing process that the residual void, birefringence, and residual stress reduced the most in similar tendency. Through such experimentation and finite element analysis, the study was able to confirm that the optimization of the LED encapsulant packaging process was possible.

  12. Estimating void fraction in a hydraulic jump by measurements of pixel intensity

    Energy Technology Data Exchange (ETDEWEB)

    Leandro, J.; Carvalho, R. [University of Coimbra, IMAR-CMA, Department of Civil Engineering, Faculty of Science and Technology, Coimbra (Portugal); Chachereau, Y.; Chanson, H. [The University of Queensland, School of Civil Engineering, Brisbane, QLD (Australia)

    2012-05-15

    A hydraulic jump is a sudden transition from supercritical to subcritical flow. It is characterized by a highly turbulent roller region with a bubbly two-phase flow structure. The present study aims to estimate the void fraction in a hydraulic jump using a flow visualization technique. The assumption that the void fraction in a hydraulic jump could be estimated based on images' pixel intensity was first proposed by Mossa and Tolve (J Fluids Eng 120:160-165, 1998). While Mossa and Tolve (J Fluids Eng 120:160-165, 1998) obtained vertically averaged air concentration values along the hydraulic jump, herein we propose a new visualization technique that provides air concentration values in a vertical 2-D matrix covering the whole area of the jump roller. The results obtained are found to be consistent with new measurements using a dual-tip conductivity probe and show that the image processing procedure (IPP) can be a powerful tool to complement intrusive probe measurements. Advantages of the new IPP include the ability to determine instantaneous and average void fractions simultaneously at different locations along the hydraulic jump without perturbing the flow, although it is acknowledged that the results are likely to be more representative in the vicinity of sidewall than at the center of the flume. (orig.)

  13. Voids and superstructures: correlations and induced large-scale velocity flows

    Science.gov (United States)

    Lares, Marcelo; Luparello, Heliana E.; Maldonado, Victoria; Ruiz, Andrés N.; Paz, Dante J.; Ceccarelli, Laura; Garcia Lambas, Diego

    2017-09-01

    The expanding complex pattern of filaments, walls and voids build the evolving cosmic web with material flowing from underdense on to high density regions. Here, we explore the dynamical behaviour of voids and galaxies in void shells relative to neighbouring overdense superstructures, using the Millenium simulation and the main galaxy catalogue in Sloan Digital Sky Survey data. We define a correlation measure to estimate the tendency of voids to be located at a given distance from a superstructure. We find voids-in-clouds (S-types) preferentially located closer to superstructures than voids-in-voids (R-types) although we obtain that voids within ˜40 h-1 Mpc of superstructures are infalling in a similar fashion independently of void type. Galaxies residing in void shells show infall towards the closest superstructure, along with the void global motion, with a differential velocity component depending on their relative position in the shell with respect to the direction to the superstructure. This effect is produced by void expansion and therefore is stronger for R-types. We also find that galaxies in void shells facing the superstructure flow towards the overdensities faster than galaxies elsewhere at the same relative distance to the superstructure. The results obtained for the simulation are also reproduced for the Sky Survey Data Release data with a linearized velocity field implementation.

  14. ESPACOMP Medication Adherence Reporting Guidelines (EMERGE): a reactive-Delphi study protocol.

    Science.gov (United States)

    Helmy, R; Zullig, L L; Dunbar-Jacob, J; Hughes, D A; Vrijens, B; Wilson, I B; De Geest, S

    2017-02-10

    Medication adherence is fundamental to achieving optimal patient outcomes. Reporting research on medication adherence suffers from some issues-including conceptualisation, measurement and data analysis-that thwart its advancement. Using the ABC taxonomy for medication adherence as the conceptual basis, a steering committee of members of the European Society for Patient Adherence, COMpliance, and Persistence (ESPACOMP) launched an initiative to develop ESPACOMP Medication Adherence Reporting Guidelines (EMERGE). This paper is a protocol for a Delphi study that aims to build consensus among a group of topic experts regarding an item list that will support developing EMERGE. This study uses a reactive-Delphi design where a group of topic experts will be asked to rate the relevance and clarity of an initial list of items, in addition to suggesting further items and/or modifications of the initial items. The initial item list, generated by the EMERGE steering committee through a structured process, consists of 26 items distributed in 2 sections: 4 items representing the taxonomy-based minimum reporting criteria, and 22 items organised according to the common reporting sections. A purposive sample of experts will be selected from relevant disciplines and diverse geographical locations. Consensus will be achieved through predefined decision rules to keep, delete or modify the items. An iterative process of online survey rounds will be carried out until consensus is reached. An ethics approval was not required for the study according to the Swiss federal act on research involving human beings. The participating experts will be asked to give an informed consent. The results of this Delphi study will feed into EMERGE, which will be disseminated through peer-reviewed publications and presentations at conferences. Additionally, the steering committee will encourage their endorsement by registering the guidelines at the Enhancing the QUAlity and Transparency Of health Research

  15. [Reactive arthritis].

    Science.gov (United States)

    Gerloni, V; Fantini, F

    1990-01-01

    The term reactive arthritis was introduced to describe an acute non-purulent arthritis complicating an infection elsewhere in the body. Reactive arthritis can also be classified into HLA-B27 associated and non-associated forms. Rheumatic fever is an example of the HLA-B27 non-associated forms with genetic factors other than HLA-B27 involved. HLA-B27 associated reactive arthritis includes enteric, urogenic and idiopathic arthritides. The bacteria known to trigger post-enteritic reactive arthritis are: Yersinia, Salmonella, Shigella, Campylobacter, Clostridium difficile and Brucella; those known to trigger post-urethritic reactive arthritis are Chlamydia trachomatis and Ureaplasma urealyticum, but often the germ remains unidentified. Mechanisms through which susceptibility to reactive arthritis is linked to HLA-B27 antigen are still incompletely understood, but a clue could be cross-reactivity between B27 and a surface antigen of pathogenic germs. The clinical profile of the disease is characterized by an asymmetrical oligoarthritis with involvement particularly of the peripheral joints of the lower limbs. The arthritis generally recovers without sequelae within a few weeks or months. Accompanying features can be the involvement of enthesis and tendon sheets in form of a talalgia or dactylitis. In some cases the arthritis can relapse and chronicize. In some cases, in addition, involvement of the axial skeleton can occur (spondylitis and/or sacroiliitis). Another feature of the disease is the frequent association with typical extra-articular manifestations such as uveitis and muco-cutaneous lesions.

  16. Cyclic voiding cystouretrography without the use of fluoroscopic monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Kadioglu, Alev [ALKA Medical Imaging Center, Buyukdere Cad. Levent Apt. No: 36/16, 80200-Mecidiyekoy, Istanbul (Turkey)]. E-mail: alevkadioglu@yahoo.com; Mihmanli, Ismail [Istanbul University, Cerrahpasa Medical Faculty, Department of Radiology, 34300-Istanbul (Turkey); Kantarci, Fatih [Istanbul University, Cerrahpasa Medical Faculty, Department of Radiology, 34300-Istanbul (Turkey); Tekes, Aylin [ALKA Medical Imaging Center, Buyukdere Cad. Levent Apt. No: 36/16, 80200-Mecidiyekoy, Istanbul (Turkey); Uysal, Omer [Istanbul University, Cerrahpasa Medical Faculty, Department of Biostatistics, 34300-Istanbul (Turkey)

    2006-01-15

    Purpose: To determine whether cyclic voiding cystourethrography (VCUG) examinations can be performed without using real-time fluoroscopic monitoring. Materials and methods: VCUG examinations were performed in 209 children (133 girls and 76 boys). In each child, it was performed in a cyclic manner (three consecutive cycles) without using fluoroscopic monitoring and one radiograph was taken in each cycle of the examination. All patients were sedated by midazolam prior to examination. The degree of vesicoureteric reflux (VUR) was graded for each of the kidney ureter units (KUU) (total 418 KUU) separately. Statistical analysis included the comparison of the presence and absence of VUR and three ordinal-matched comparisons of each cycle. Results: VCUG was detected in 37.3% of the children (78/209) and 28.7% (120/418) of the KUU. The absence of or same degree of VUR in three consecutive cycles were obtained in 345 KUU and the agreement was calculated as 82.5%. The same degree and presence of reflux were found in 85 and 89 refluxing KUU, the same negative findings (absence of VUR) in 306 and 298 KUU, and discordant findings in 27 and 31 KUU (between the first and second and between first and third cycles), respectively. Therefore, the agreement was 93.5 and 92.5% between the first and second cycles (p = 0.70) and between the first and the third cycles (p = 0.15), respectively. Conclusion: Both the cyclic nature of this study and the results indicated that VCUG without real-time fluoroscopic monitoring could be used where adequate fluoroscopic examination is not possible for children in whom VUR detection is necessary and impacts treatment. However, the responsibility of pediatric radiologist always must also include the task to provide proper equipment for imaging children with suspected VUR.

  17. Relationship between C-reactive protein and stroke: a large prospective community based study.

    Directory of Open Access Journals (Sweden)

    Yanfang Liu

    Full Text Available Previous studies have suggested that C-reactive protein (CRP was associated with risk of stroke. There were few studies in Asian population, or on stroke subtypes other than ischemic stroke. We thus investigated the relationship between CRP and the risks of all stroke and its subtypes in a Chinese adult population.In the current study, we included 90,517 Chinese adults free of stroke and myocardial infarction at baseline (June 2006 to October 2007 in analyses. Strokes were classified as ischemic stroke (IS, intracranial heamorrhage (ICH and subarachnoid heamorrhage (SAH. High-sensitivity CRP (hs-CRP were categorized into three groups: 3 mg/L. Cox proportional hazards regression was used to calculate the association between hs-CRP concentrations and all stroke, as well as its subtypes.During a median follow-up time of 49 months, we documented 1,472 incident stroke cases. Of which 1,049 (71.3% were IS, 383 (26.0% were ICH, and 40 (2.7% were SAH. After multivariate adjustment, hs-CRP concentrations ≥1 mg/L were associated with increased risks of all stroke (hs-CRP 1-3 mg/L: hazard ratio (HR 1.17, 95% confidential interval (CI 1.03-1.33; hs-CRP>3 mg/L: HR 1.25, 95% CI 1.07-1.46 and IS (hs-CRP 1-3 mg/L: HR 1.17, 95% CI 1.01-1.36; hs-CRP>3 mg/L: HR 1.33, 95% CI 1.11-1.60, but not with ICH and SAH. Subgroup analyses showed that higher hs-CRP concentration was more prone to be a risk factor for all stroke and IS in non-fatal stroke, male and hypertensive participants.We found that higher hs-CRP concentrations were associated with a higher risk of IS, particularly for non-fatal stroke, male and hypertensive subjects. In contrast, we did not observe significant associations between hs-CRP and ICH/SAH.

  18. Daytime napping, sleep duration and serum C reactive protein: a population-based cohort study.

    Science.gov (United States)

    Leng, Yue; Ahmadi-Abhari, Sara; Wainwright, Nick W J; Cappuccio, Francesco P; Surtees, Paul G; Luben, Robert; Brayne, Carol; Khaw, Kay-Tee

    2014-11-11

    To explore whether daytime napping and sleep duration are linked to serum C reactive protein (CRP), a pro-inflammatory marker, in an older aged British population. Cross-sectional study. European Prospective Investigation into Cancer and Nutrition (EPIC)-Norfolk study. A total of 5018 men and women aged 48-92 years reported their sleep habits and had serum CRP levels measured. CRP was measured (mg/L) during 2006-2011 in fresh blood samples using high-sensitivity methods. Participants reported napping habits during 2002-2004, and reported sleep quantity during 2006-2007. Multivariable linear regression models were used to examine the association between napping and log-transformed CRP, and geometric mean CRP levels were calculated. After adjustment for age and sex, those who reported napping had 10% higher CRP levels compared with those not napping. The association was attenuated but remained borderline significant (β=0.05 (95% CI 0.00 to 0.10)) after further adjustment for social class, education, marital status, body mass index, physical activity, smoking, alcohol intake, self-reported health, pre-existing diseases, systolic blood pressure, hypnotic drug use, depression and in women-only hormone replacement therapy use. The geometric means (95% CI) of CRP levels were 2.38 (2.29 to 2.47) mg/L and 2.26 (2.21 to 2.32) mg/L for those who reported napping and no napping, respectively. A U-shaped association was observed between time spent in bed at night and CRP levels, and nighttime sleep duration was not associated with serum CRP levels. The association between napping and CRP was stronger for older participants, and among extremes of time spent in bed at night. Daytime napping was associated with increased CRP levels in an older aged British population. Further studies are needed to determine whether daytime napping is a cause for systemic inflammation, or if it is a symptom or consequence of underlying health problems. Published by the BMJ Publishing Group Limited

  19. Simulation-aided constitutive law development - Assessment of low triaxiality void nucleation models via extended finite element method

    Science.gov (United States)

    Zhao, Jifeng; Kontsevoi, Oleg Y.; Xiong, Wei; Smith, Jacob

    2017-05-01

    In this work, a multi-scale computational framework has been established in order to investigate, refine and validate constitutive behaviors in the context of the Gurson-Tvergaard-Needleman (GTN) void mechanics model. The eXtended Finite Element Method (XFEM) has been implemented in order to (1) develop statistical volume elements (SVE) of a matrix material with subscale inclusions and (2) to simulate the multi-void nucleation process due to interface debonding between the matrix and particle phases. Our analyses strongly suggest that under low stress triaxiality the nucleation rate of the voids f˙ can be well described by a normal distribution function with respect to the matrix equivalent stress (σe), as opposed to that proposed (σbar + 1 / 3σkk) in the original form of the single void GTN model. The modified form of the multi-void nucleation model has been validated based on a series of numerical experiments with different loading conditions, material properties, particle shape/size and spatial distributions. The utilization of XFEM allows for an invariant finite element mesh to represent varying microstructures, which implies suitability for drastically reducing complexity in generating the finite element discretizations for large stochastic arrays of microstructure configurations. The modified form of the multi-void nucleation model is further applied to study high strength steels by incorporating first principles calculations. The necessity of using a phenomenological interface separation law has been fully eliminated and replaced by the physics-based cohesive relationship obtained from Density Functional Theory (DFT) calculations in order to provide an accurate macroscopic material response.

  20. Detection of atomic scale changes in the free volume void size of three-dimensional colorectal cancer cell culture using positron annihilation lifetime spectroscopy.

    Science.gov (United States)

    Axpe, Eneko; Lopez-Euba, Tamara; Castellanos-Rubio, Ainara; Merida, David; Garcia, Jose Angel; Plaza-Izurieta, Leticia; Fernandez-Jimenez, Nora; Plazaola, Fernando; Bilbao, Jose Ramon

    2014-01-01

    Positron annihilation lifetime spectroscopy (PALS) provides a direct measurement of the free volume void sizes in polymers and biological systems. This free volume is critical in explaining and understanding physical and mechanical properties of polymers. Moreover, PALS has been recently proposed as a potential tool in detecting cancer at early stages, probing the differences in the subnanometer scale free volume voids between cancerous/healthy skin samples of the same patient. Despite several investigations on free volume in complex cancerous tissues, no positron annihilation studies of living cancer cell cultures have been reported. We demonstrate that PALS can be applied to the study in human living 3D cell cultures. The technique is also capable to detect atomic scale changes in the size of the free volume voids due to the biological responses to TGF-β. PALS may be developed to characterize the effect of different culture conditions in the free volume voids of cells grown in vitro.

  1. Theoretical Study about the Effect of Halogen Substitution on the Reactivity of Antitumor 3-Formylchromones and Their Free Radicals

    Directory of Open Access Journals (Sweden)

    Maximiliano Martínez-Cifuentes

    2017-01-01

    Full Text Available The mandatory presence of a chlorine atom on the aromatic ring of 6-hydroxy-3-formyl angular chromones, on the respiration inhibition of mammary carcinoma mouse, is explained through a computational study of these compounds. This study analyzes the reactivity of the neutral molecules and their free radicals, in gas phase and with water solvation, incorporated by the polarizable continuum medium (PCM approach. Electrophilic reactivities were evaluated using Fukui (f+ and Parr (P+ functions. The stabilities of radical species formed by the abstraction of a hydrogen atom from the O-H bond were evaluated by bond dissociation enthalpy (BDE and spin density (SD calculations. This study has potential implications for the design of chromone analogues as anticancer compounds.

  2. Synthesis, structural characterization, and reactivity studies of 5-CF3SO3-B10H13.

    Science.gov (United States)

    Berkeley, Emily R; Ewing, William C; Carroll, Patrick J; Sneddon, Larry G

    2014-05-19

    In contrast to previous reactions carried out in cyclopentane solvent at room temperature that produced 6-TfO-B10H13 (TfO = CF3SO3), the reaction of closo-B10H10(2-) with a large excess of trifluoromethanesulfonic acid in the ionic liquid 1-butyl-3-methylimidazolium trifluoromethanesulfonate (bmimOTf) gave exclusively the previously unknown 5-TfO-B10H13 isomer. Experimental and computational studies demonstrated that the difference in the products of the two reactions is a result of 6-TfO-B10H13 isomerizing to 5-TfO-B10H13 above room temperature in bmimOTf solutions. Reactivity studies showed that 5-TfO-B10H13: (1) is deprotonated by reaction with 1,8-bis(dimethylamino)naphthalene to form the 5-TfO-B10H12(1-) anion; (2) reacts with alcohols to produce 6-RO-B10H13 boryl ethers (R = Me and 4-CH3O-C6H4); (3) undergoes olefin-hydroboration reactions to form 5-TfO-6,9-R2-B10H11 derivatives; and (4) forms a 5-TfO-6,9-(Me2S)2-B10H11 adduct at its Lewis acidic 6,9-borons upon reaction with dimethylsulfide. The 5-TfO-6,9-(Me2S)2-B10H11 adduct was also found to undergo alkyne-insertion reactions to form a range of previously unreported triflate-substituted 4-TfO-ortho-carboranes (1-R-4-TfO-1,2-C2B10H10) and reactions with triethylamine or ammonia to form the first TfO-substituted decaborate [R3NH(+)]2[2-TfO-B10H9(2-)], and [R3NH(+)]2[1-TfO-B10H9(2-)] (R = H, Et) salts.

  3. Behaviour of voids in a shear field

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2009-01-01

    to a plane connecting the ends of the micro-crack is used as an approximate representation of contact stresses during frictionless sliding. In a previous study of the same problem the author applied hydrostatic pressure inside the nearly closed micro-crack to approximate contact conditions. The transverse...... a maximum in all the cases analyzed and thus illustrates the micro-mechanism leading to failure of the material by localization of plastic flow....

  4. Theoretical Studies of Oxygen Reactivity of Free-Standing and Supported Boron-Doped Graphene.

    Science.gov (United States)

    Di Valentin, Cristiana; Ferrighi, Lara; Fazio, Gianluca

    2016-05-23

    Graphene inertness towards chemical reactivity can be considered as an accepted postulate by the research community. This limit has been recently overcome by chemically and physically modifying graphene through non-metal doping or interfacing with acceptor/donor materials (metals or semiconductors). As a result, outstanding performances as catalytic, electrocatalytic, and photocatalytic material have been observed. In this critical Review we report computational work performed, by our group, on the reactivity of free-standing, metal- and semiconductor-supported B-doped graphene towards oxygen, which is at the basis of extremely important energy-related chemical processes, such as the oxygen reduction reaction. It appears that a combination of doping and interfacing approaches for the activation of graphene can open unconventional and unprecedented reaction paths, thus boosting the potential of modified graphene in many chemical applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Reactive Systems

    DEFF Research Database (Denmark)

    Aceto, Luca; Ingolfsdottir, Anna; Larsen, Kim Guldstrand

    A reactive system comprises networks of computing components, achieving their goals through interaction among themselves and their environment. Thus even relatively small systems may exhibit unexpectedly complex behaviours. As moreover reactive systems are often used in safety critical systems......, the need for mathematically based formal methodology is increasingly important. There are many books that look at particular methodologies for such systems. This book offers a more balanced introduction for graduate students and describes the various approaches, their strengths and weaknesses, and when...

  6. Reactive Systems

    DEFF Research Database (Denmark)

    Aceto, Luca; Ingolfsdottir, Anna; Larsen, Kim Guldstrand

    A reactive system comprises networks of computing components, achieving their goals through interaction among themselves and their environment. Thus even relatively small systems may exhibit unexpectedly complex behaviours. As moreover reactive systems are often used in safety critical systems, t...... into account. The book has arisen from various courses taught in Denmark and Iceland and is designed to give students a broad introduction to the area, with exercises throughout....

  7. Study of Reactive Materials for Development of new Protective Clothing Concepts

    Science.gov (United States)

    1977-10-01

    colorless but reactive dyes have been applied to nonwoven substrates, such as paper, to pro- duce ca.:bonless copy paper, e.g., NCR’s "no- carbon -required...particles of active materials in protective or functional coatings, is being investigated in the development of new protective clothing concepts. We are...that microcapsules comprising ethyl cellu- lose as the wall material and XXCC3 as the core material would de- activate neat mustard rapidly. We are now

  8. Study of Na-Montmorillonite–Polyamide Fiber/Polypropylene Hybrid Composite Prepared by Reactive Melt Mixing

    OpenAIRE

    Samia Kerakra; Said Bouhelal; Marc Ponçot

    2017-01-01

    Hybrid composites of polypropylene (PP)/sodium montmorillonite (Na-MMT)/short polyamide fibers (PAfs) were prepared by reactive melt mixing in a Brabender plastograph. To enhance filler interactions within polypropylene, a functionalizing agent (FA) and a coupling agent were added to the Na-MMT and PAfs, respectively. An organic peroxide/sulfur mixture and tetramethylthiuram disulfide as an activator for sulfur were used to functionalize Na-MMT; on the other hand, the PAfs surface was treated...

  9. Reactive Chemical Transport Simulation to Study Geothermal Production with Mineral Recovery and Silica Scaling

    OpenAIRE

    Xu, Tianfu; Pruess, Karsten; Pham, Minh; Klein, Christopher; Sanyal, Subir

    2001-01-01

    There are vast reserves of dissolved minerals in the hypersaline brines of geothermal fields in the Imperial Valley of California. Recovery of zinc from geothermal brines is being practiced in this area, and recovery of silica, manganese, silver, lead and lithium has been or is being considered. Therefore, the ability to model mineral recovery is very significant in terms of economic development and resource utilization. The reactive geochemical transport simulator TOUGHREACT has been used to...

  10. IJIERT-STUDY ON THE EFFECT OF REACTIVE POWDER CONCRETE ON THE COMPRESSIVE STRENGTH AND WORKABILITY

    OpenAIRE

    ADITYA PATIL; VISHAL PATIL; AKASH PATIL

    2017-01-01

    The low tensile strength of concrete has many undesirable consequences for its performance as an efficient building material. This includes the need to support rebars as well as the requirement for thick-walled components that are beautiful and consume large quantities of aggregates. The total is an increasingly scarce resource in many urban areas. Reactive powder concrete(RPC) is a new technology that overcomes these limitations. Avoid aggregation in RPC to overcome the associated issues. RP...

  11. The study of the functional state of the endothelium via a complex of markers with reactive hyperemia

    Directory of Open Access Journals (Sweden)

    Berezhniy V.

    2016-03-01

    Full Text Available Diagnosis of endothelial dysfunction is a key point in the prevention and treatment of cardiovascular diseases. In scientific research the study of the state of the endothelium used test with reactive hyperemia of brachial artery wich present as the value of endothelium dependent and independent artery dilatation. However, the disadvantage of this marker is ignoring the size of arteries, well know that small arteries has a greater degree of dilation more than big arterias, this fact making difficult to compare results between different patients. The aim of our study was to examine the state of endothelium using a complex of markers, compare them informative in children with JRA who are at risk for the development of endothelial dysfunction. Materials and Methods. The study was included 40 children with juvenile rheumatoid arthritis who were treated at the department of children's cardiorheumatology Kyiv City Children's Hospital #1 and Kiev Regional Hospital m. Boyarka. Results. The study found a development of endothelial dysfunction changes in endothelium dependent vasodilation, reactive hyperemia and coefficient of vasodilation. Simultaneous marked change of endothelium vasodilation of the brachial artery and coefficient of vasodilatation. There were no pathological changes in endothelial shear stress in patients compared with healthy children. Conclusions. Evaluate the state of the endothelium is necessary with the help of a set of indicators (RH, EDVD, VC that will help to avoid diagnostic mistakes during the test with the reactive hyperemia.

  12. Surface Reactivity of Li2MnO3: First-Principles and Experimental Study.

    Science.gov (United States)

    Quesne-Turin, Ambroise; Flahaut, Delphine; Croguennec, Laurence; Vallverdu, Germain; Allouche, Joachim; Charles-Blin, Youn; Chotard, Jean-Noël; Ménétrier, Michel; Baraille, Isabelle

    2017-12-20

    This article deals with the surface reactivity of (001)-oriented Li 2 MnO 3 crystals investigated from a multitechnique approach combining material synthesis, X-ray photoemission spectroscopy (XPS), scanning electron microscopy, Auger electron spectroscopy, and first-principles calculations. Li 2 MnO 3 is considered as a model compound suitable to go further in the understanding of the role of tetravalent manganese atoms in the surface reactivity of layered lithium oxides. The knowledge of the surface properties of such materials is essential to understand the mechanisms involved in parasitic phenomena responsible for early aging or poor storage performances of lithium-ion batteries. The surface reactivity was probed through the adsorption of SO 2 gas molecules on large Li 2 MnO 3 crystals to be able to focus the XPS beam on the top of the (001) surface. A chemical mapping and XPS characterization of the material before and after SO 2 adsorption show in particular that the adsorption is homogeneous at the micro- and nanoscale and involves Mn reduction, whereas first-principles calculations on a slab model of the surface allow us to conclude that the most energetically favorable species formed is a sulfate with charge transfer implying reduction of Mn.

  13. Intense passionate love attenuates cigarette cue-reactivity in nicotine-deprived smokers: an FMRI study.

    Directory of Open Access Journals (Sweden)

    Xiaomeng Xu

    Full Text Available Self-expanding experiences like falling in love or engaging in novel, exciting and interesting activities activate the same brain reward mechanism (mesolimbic dopamine pathway that reinforces drug use and abuse, including tobacco smoking. This suggests the possibility that reward from smoking is substitutable by self-expansion (through competition with the same neural system, potentially aiding cessation efforts. Using a model of self-expansion in the context of romantic love, the present fMRI experiment examined whether, among nicotine-deprived smokers, relationship self-expansion is associated with deactivation of cigarette cue-reactivity regions. Results indicated that among participants who were experiencing moderate levels of craving, cigarette cue-reactivity regions (e.g., cuneus and posterior cingulate cortex showed significantly less activation during self-expansion conditions compared with control conditions. These results provide evidence that rewards from one domain (self-expansion can act as a substitute for reward from another domain (nicotine to attenuate cigarette cue reactivity.

  14. Diagnostic value of cytology of voided urine.

    Science.gov (United States)

    Milicić, Valerija; Prvulović, Ivana; Panda, Natalija; Bilić-Kirin, Vesna; Kraljik, Nikola; Serić, Vatroslav

    2014-06-01

    There are 961 new cases and approximately 366 deaths from urothelial carcinoma registered annually in Croatia. Exfoliative urinary cytology has important role in detection of high grade urinary tumors, invasive and in situ lesions respectively. In contrast to cystoscopy and biopsy, cytology is a noninvasive method which is easily repeated. The aim of this retrospective study was to assess value of urinary cytology in our institution. For this purpose only patients with histological diagnosis and clinical follow up were considered. There were 138 urine specimens with cytological diagnosis of dyskaryosis, suspicious for malignancy or malignant and histology and follow up data examined at our Department of Clinical Cytology between 2004 and 2011. Cytological diagnosis suspicious for malignancy and malignant were considered positive and the results were correlated with histological diagnosis according to the WHO histological classification of tumors of the urinary tract. Patients with negative histological findings were followed for the next two years. The positive predictive value of cytological detection of malignant urothelial lesions was 91.8%. In 10 cases cytological diagnosis of malignancy was not confirmed histologically or clinically which makes the total of 8.2% of false positive reports. Of the total of detected malignant urothelial lesions 90.9% are high grade lesions and only 9.1% low-grade lesions; 67.3% are invasive lesions and 32.7% non-invasive lesions. Cytological findings of dyskariotyc cells requires further urological investigation because such findings in further processing prove the presence of tumor in 93.8% of cases. In conclusion: cytology is very good diagnostic tool for detection of high grade invasive and noninvasive carcinomas of the urinary tract. In order to make it more efficient we need to study its limits carefully, define diagnostic criteria and reach consensus in nomenclature.

  15. Reactivity Studies of 2,6-Bis-(1,2,3-triazolyl)purine Nucleosides with Hydrazines and Amino Acids

    OpenAIRE

    Laķis, E; Novosjolova, I; Bizdēna, Ē; Turks, M

    2014-01-01

    Reactions of 2,6-bis-(1,2,3-triazolyl)purine nucleosides with nucleophiles is efficient route to C(6)-derivatization of purine base. To extend the field of application of the method, we studied reactivity of bis-(1,2,3-triazolyl)purine derivatives toward hydrazines and amino acids and obtained nucleosides substituted at C(6) with hydrazine and amino acid moieties.

  16. Perceived stress, coping, and cortisol reactivity in daily life: A study of adolescents during the first year of college

    OpenAIRE

    Sladek, Michael R.; Doane, Leah D.; Luecken, Linda J.; Eisenberg, Nancy

    2016-01-01

    Adolescents change how they cope with stress across different situations, but also differ from one another in their general capacity to cope. The current study examined whether cortisol reactivity to perceived daily stress varies with both situational (within-person) and individual (between-person) differences in coping. First-year college students (N = 63; Mage = 18.85) provided 15 stress-coping diaries and 15 corresponding saliva samples across 3 weekdays. Results from hierarchical linear g...

  17. Flows of Reactive Fluids

    CERN Document Server

    Prud'homme, Roger

    2010-01-01

    The modeling of reactive flows has progressed mainly with advances in aerospace, which gave birth to a new science called aerothermochemistry, as well as through developments in chemical and process engineering. The methods employed, the phenomena investigated, and the aims of modeling differ for each field; however, in all cases, the results obtained have considerably enriched the working knowledge of reactive flows. This work examines basic concepts and methods necessary to study reactive flows and transfer phenomena in areas such as fluid mechanics, thermodynamics, and chemistry. Specific topics covered include: * Equations of state * Transfer phenomena and chemical kinetics * Balance equations of reactive flows * Dimensionless numbers and similarity * Chemical reactors * Coupled phenomena * Turbulent flow concepts * Boundary layers and fluid layers * Reactive and nonreactive waves * Interface phenomena * Multiphase flow concepts The book presents tools of interest to graduate students, researchers in math...

  18. Reactivity feedback coefficients Pakistan research reactor-1 using PRIDE code

    Energy Technology Data Exchange (ETDEWEB)

    Mansoor, Ali; Ahmed, Siraj-ul-Islam; Khan, Rustam [Pakistan Institute of Engineering and Applied Sciences, Islamabad (Pakistan). Dept. of Nuclear Engineering; Inam-ul-Haq [Comsats Institute of Information Technology, Islamabad (Pakistan). Dept. of Physics

    2017-05-15

    Results of the analyses performed for fuel, moderator and void's temperature feedback reactivity coefficients for the first high power core configuration of Pakistan Research Reactor - 1 (PARR-1) are summarized. For this purpose, a validated three dimensional model of PARR-1 core was developed and confirmed against the reference results for reactivity calculations. The ''Program for Reactor In-Core Analysis using Diffusion Equation'' (PRIDE) code was used for development of global (3-dimensional) model in conjunction with WIMSD4 for lattice cell modeling. Values for isothermal fuel, moderator and void's temperature feedback reactivity coefficients have been calculated. Additionally, flux profiles for the five energy groups were also generated.

  19. The Influence of the Presence of Multiple Voids on the Discharge Patterns in Solid Epoxy Insulation

    DEFF Research Database (Denmark)

    Holbøll, Joachim T.; Henriksen, Mogens; Larsen, Esben

    1996-01-01

    In this paper, partial discharge test results from initial long term testing on samples which contain more voids, when exposed to a high electric stress will be presented. The influence on the discharge patterns, phase- and height-analyses, of such parameter as the number of voids and the void di...

  20. 21 CFR 888.3045 - Resorbable calcium salt bone void filler device.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Resorbable calcium salt bone void filler device. 888.3045 Section 888.3045 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... salt bone void filler device. (a) Identification. A resorbable calcium salt bone void filler device is...

  1. Laboratory and exterior decay of wood plastic composite boards: voids analysis and computed tomography

    Science.gov (United States)

    Grace Sun; Rebecca E. Ibach; Meghan Faillace; Marek Gnatowski; Jessie A. Glaeser; John Haight

    2016-01-01

    After exposure in the field and laboratory soil block culture testing, the void content of wood–plastic composite (WPC) decking boards was compared to unexposed samples. A void volume analysis was conducted based on calculations of sample density and from micro-computed tomography (microCT) data. It was found that reference WPC contains voids of different sizes from...

  2. Elastic–plastic void expansion in near-self-similar shapes

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2011-01-01

    For void growth in an elastic–plastic strain hardening material the preferred shape of the void is calculated, dependent on the macroscopic stress state. Axisymmetric cell model analyses are carried out with a very small initial void size relative to the cell dimensions. Large deformations of the...

  3. Modelling the void deformation and closure by hot forging of ingot castings

    DEFF Research Database (Denmark)

    Christiansen, Peter; Hattel, Jesper Henri; Kotas, Petr

    2012-01-01

    . The analysis concernsboth the void density change and the location of the voids in the part after deformation. The latter can be important for the subsequent reliability of the parts, for instance regarding fatigue properties. The analysis incorporates the Gurson yield criterion for metals containing voids...

  4. 42 CFR 457.216 - Treatment of uncashed or canceled (voided) CHIP checks.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 4 2010-10-01 2010-10-01 false Treatment of uncashed or canceled (voided) CHIP... canceled (voided) CHIP checks. (a) Purpose. This section provides rules to ensure that States refund the... section— Canceled (voided) check means an CHIP check issued by a State or fiscal agent that prior to its...

  5. A theoretical analysis of the electromigration-induced void morphological evolution under high current density

    Science.gov (United States)

    Wang, Yuexing; Yao, Yao

    2017-10-01

    In this work, analysis of electromigration-induced void morphological evolution in solder interconnects is performed based on mass diffusion theory. The analysis is conducted for three typical experimentally observed void shapes: circular, ellipse, and cardioid. Void morphological evolution is governed by the competition between the electric field and surface capillary force. In the developed model, both the electric field and capillary force on the void's surface are solved analytically. Based on the mass conversation principle, the normal velocity on the void surface during diffusion is obtained. The void morphological evolution behavior is investigated, and a physical model is developed to predict void collapse to a crack or to split into sub-voids under electric current. It is noted that when the electric current is being applied from the horizontal direction, a circular void may either move stably along the electric current direction or collapse to a finger shape, depending on the relative magnitude of the electric current and surface capillary force. However, the elliptical-shaped void will elongate along the electric current direction and finally collapse to the finger shape. On the other hand, the cardioid-shaped void could bifurcate into two sub-voids when the electric current reaches a critical value. The theoretical predictions agree well with the experimental observations.

  6. Development of Improved Connection Details for Voided Slab Bridges

    OpenAIRE

    Joyce, Patrick Conor

    2014-01-01

    Adjacent voided slab bridges (AVSB) are economical systems for short spans. They provide the advantages of having low clearances due to their small section depths, accelerated construction times, and high torsional stiffness. The current longitudinal connection detail, a partial depth grouted shear key, has been known to fail in many of these bridges. The failure leads to reflective cracking in the wearing surface which allows chloride laden water to seep down through the joint, where it c...

  7. Aberration-corrected electron microscopy of MnAs and As nanocrystals and voids in annealed (Ga,Mn)As

    DEFF Research Database (Denmark)

    Kovács, András; Kasama, Takeshi; Sadowski, J.

    2011-01-01

    Aberration-corrected transmission electron microscopy is used to study voids and nano-crystalline MnAs and As phases formed during the annealing of Mn-doped GaAs. The effects of defocus and inner annular dark-field detector semi-angle on contrast of the nanocrystals are discussed....

  8. A Comparative Study of Arm-Restraint Methodology: Differential Effects of Mother and Stranger Restrainers on Infants' Distress Reactivity at 6 and 9 Months of Age

    Science.gov (United States)

    Porter, Christin L.; Jones, Blake L.; Evans, Cortney A.; Robinson, Clyde C.

    2009-01-01

    This study examined both differential patterns and the stability of infants' (N = 70) distress reactivity across mother and stranger arm-restraint conditions when infants were 6 and 9 months of age. Reactivity measures included observational variables for the rise, intensity, and duration of infant distress as well as motor activities associated…

  9. Multipole analysis of redshift-space distortions around cosmic voids

    Science.gov (United States)

    Hamaus, Nico; Cousinou, Marie-Claude; Pisani, Alice; Aubert, Marie; Escoffier, Stéphanie; Weller, Jochen

    2017-07-01

    We perform a comprehensive redshift-space distortion analysis based on cosmic voids in the large-scale distribution of galaxies observed with the Sloan Digital Sky Survey. To this end, we measure multipoles of the void-galaxy cross-correlation function and compare them with standard model predictions in cosmology. Merely considering linear-order theory allows us to accurately describe the data on the entire available range of scales and to probe void-centric distances down to about 2 h-1Mpc. Common systematics, such as the Fingers-of-God effect, scale-dependent galaxy bias, and nonlinear clustering do not seem to play a significant role in our analysis. We constrain the growth rate of structure via the redshift-space distortion parameter β at two median redshifts, β(bar z=0.32)=0.599+0.134-0.124 and β(bar z=0.54)=0.457+0.056-0.054, with a precision that is competitive with state-of-the-art galaxy-clustering results. While the high-redshift constraint perfectly agrees with model expectations, we observe a mild 2σ deviation at bar z=0.32, which increases to 3σ when the data is restricted to the lowest available redshift range of 0.15

  10. Piezoelectric performance of fluor polymer sandwiches with different void structures

    Science.gov (United States)

    Lou, Kexing; Zhang, Xiaoqing; Xia, Zhongfu

    2012-06-01

    Film sandwiches, consisting of two outer layers of fluoroethylenepropylene and one middle layer of patterned porous polytetrafluoroethylene, were prepared by patterning and fusion bonding. Contact charging was conducted to render the films piezoelectric. The critical voltage to trigger air breakdown in the inner voids in the fabricated films was investigated. The piezoelectric d 33 coefficients were measured employing the quasistatic method and dielectric resonance spectrum. The results show that the critical voltage for air breakdown in the inner voids is associated with the void microstructure of the films. For the films with patterning factors of 0%, 25% and 44%, the critical values are 300, 230 and 230 kV/cm, respectively. With an increase in the patterning factor, both the piezoelectric d 33 coefficients determined from the dielectric resonance spectra and those determined from quasistatic measurements increase, which might be due to a decrease in Young's modulus for the films. The nonlinearity of d 33 becomes increasingly obvious as the patterning factor increases.

  11. Meandering flow void around the splenium in moyamoya disease.

    Science.gov (United States)

    Mikami, Takeshi; Kuribara, Tomoyoshi; Komatsu, Katsuya; Kimura, Yusuke; Wanibuchi, Masahiko; Houkin, Kiyohiro; Mikuni, Nobuhiro

    2017-08-01

    Meandering flow void around the splenium, which can be recognized on conventional T2-weighted images, implicates collateral flow in the splenial artery in patients with moyamoya disease. In this report, curves of flow voids around the splenium (SFVs) were evaluated in patients with moyamoya disease, and their diagnostic value and pathophysiology were verified. A total of 65 consecutive patients with moyamoya disease were included in this analysis. The number of SFV curves was counted on each side. The numbers of SFV curves in patients with moyamoya disease was compared with those in the control group. The clinical features of patients with large numbers of flow voids were analyzed. The mean number of SFVs was significantly higher in the moyamoya disease group than in the control group or the atherosclerotic disease group. The cut-off SFV count for a diagnosis of moyamoya disease should be set to 2.25 in consideration of receiver operating characteristic curve analysis. A multivariate logistic analysis of SFV data in moyamoya disease revealed significant differences between the high SFV count group (≥2.25) and the low SFV count group (moyamoya disease. Increased number of SFV curves was associated with age and progress of disease.

  12. Dwarf Galaxies in Voids: Dark Matter Halos and Gas Cooling

    Directory of Open Access Journals (Sweden)

    Matthias Hoeft

    2010-01-01

    Full Text Available Galaxy surveys have shown that luminous galaxies are mainly distributed in large filaments and galaxy clusters. The remaining large volumes are virtually devoid of luminous galaxies. This is in concordance with the formation of the large-scale structure in the universe as derived from cosmological simulations. However, the numerical results indicate that cosmological voids are abundantly populated with dark matter haloes which may in principle host dwarf galaxies. Observational efforts have in contrast revealed that voids are apparently devoid of dwarf galaxies. We investigate the formation of dwarf galaxies in voids by hydrodynamical cosmological simulations. Due to the cosmic ultraviolet background radiation low-mass haloes show generally a reduced baryon fraction. We determine the characteristic mass below which dwarf galaxies are baryon deficient. We show that the circular velocity below which the accretion of baryons is suppressed is approximately 40 kms−1. The suppressed baryon accretion is caused by the photo-heating due to the UV background. We set up a spherical halo model and show that the effective equation of the state of the gas in the periphery of dwarf galaxies determines the characteristic mass. This implies that any process which heats the gas around dwarf galaxies increases the characteristic mass and thus reduces the number of observable dwarf galaxies.

  13. Effects of Heterogeneous Sink Distribution on Void Swelling

    DEFF Research Database (Denmark)

    Leffers, Torben; Volobuyev, A. V.; Gann, V. V.

    1986-01-01

    Swelling rates are calculated for two types of material with heterogeneous distributions of dislocations and voids, namely copper irradiated with neutrons to low dose at 250 degree C and heavily cold-worked copper irradiated with 1 MeV electrons in a HVEM at 250 degree C. Both materials are consi......Swelling rates are calculated for two types of material with heterogeneous distributions of dislocations and voids, namely copper irradiated with neutrons to low dose at 250 degree C and heavily cold-worked copper irradiated with 1 MeV electrons in a HVEM at 250 degree C. Both materials...... are considered to consist of non-interacting spherical components with a wall and an inner cell with different dislocation and/or void densities. We subdivide the sphere (wall plus cell) in a number of concentric shells and find a quasi-static solution for the interstitial and vacancy concentrations...... in the different shells by a finite-difference method. From these concentrations the local and the average swelling rate and the dependence of this effect of the heterogeneities in sink distribution on swelling rate and the dependence of this effect on various structural parameters are investigated....

  14. Obesity-Induced Diabetes and Lower Urinary Tract Fibrosis Promote Urinary Voiding Dysfunction in a Mouse Model

    Science.gov (United States)

    Gharaee-Kermani, Mehrnaz; Rodriguez-Nieves, Jose A.; Mehra, Rohit; Vezina, Chad A.; Sarma, Aruna V.; Macoska, Jill A.

    2017-01-01

    BACKGROUND Progressive aging- and inflammation-associated fibrosis effectively remodels the extracellular matrix (ECM) to increase prostate tissue stiffness and reduce urethral flexibility, resulting in urinary flow obstruction and lower urinary tract symptoms (LUTS). In the current study, we sought to test whether senescence-accelerated mouse prone (SAMP)6 mice, which were reported to develop prostatic fibrosis, would also develop LUTS, and whether these symptoms would be exacerbated by diet-induced obesity and concurrent Type 2 Diabetes Mellitus (T2DM). METHODS To accomplish this, SAMP6 and AKR/J background strain mice were fed regular mouse chow, low fat diet chow, or high fat diet chow for 8 months, then subjected to glucose tolerance tests, assessed for plasma insulin levels, evaluated for urinary voiding function, and assessed for lower urinary tract fibrosis. RESULTS The results of these studies show that SAMP6 mice and AKR/J background strain mice develop diet-induced obesity and T2DM concurrent with urinary voiding dysfunction. Moreover, urinary voiding dysfunction was more severe in SAMP6 than AKR/J mice and was associated with pronounced prostatic and urethral tissue fibrosis. CONCLUSIONS Taken together, these studies suggest that obesity, T2DM, lower urinary tract fibrosis, and urinary voiding dysfunction are inextricably and biologically linked. Prostate. PMID:23532836

  15. Chemical Reactivity of Isoproturon, Diuron, Linuron, and Chlorotoluron Herbicides in Aqueous Phase: A Theoretical Quantum Study Employing Global and Local Reactivity Descriptors

    Directory of Open Access Journals (Sweden)

    Luis Humberto Mendoza-Huizar

    2015-01-01

    Full Text Available We have calculated global and local DFT reactivity descriptors for isoproturon, diuron, linuron, and chlorotoluron herbicides at the MP2/6-311++G(2d,2p level of theory. The results suggest that, in aqueous conditions, chlorotoluron, linuron, and diuron herbicides may be degraded by elimination of urea moiety through electrophilic attacks. On the other hand, electrophilic, nucleophilic, and free radical attacks on isoproturon may cause the elimination of isopropyl fragment.

  16. Towards the new heterocycle based molecule: Synthesis, characterization and reactivity study

    Science.gov (United States)

    Murthy, P. Krishna; Sheena Mary, Y.; Suneetha, V.; Panicker, C. Yohannan; Armaković, Stevan; Armaković, Sanja J.; Giri, L.; Suchetan, P. A.; Van Alsenoy, C.

    2017-06-01

    4-Chloro-2-(3-fluorophenyl)-2,3-dihydro-1H-pyrrolo[3,4-c]pyridin-1-one (CFPDPPO) have been synthesized by hydride transfer from Et3SiH to carbenium ions(reduction reaction), which is formed by reaction between 4-chloro-2-(3-fluorophenyl)-3-hydroxy-2,3-dihydro-1H-pyrrolo[3,4-c]pyridin-1-one with TFA, the single crystals were grown in acetonitrile by slow evaporation technique at room temperature and characterized by single crystal X-ray diffraction, FT-IR, FT-Raman, 1H NMR, 13C NMR and ESI-MS. The experimental vibrational spectra were compared with the calculated spectra and each vibrational wavenumber was assigned on the basis of potential energy distribution (PED). Gauge-including atomic orbital 1H NMR and 13C NMR chemical shifts calculations were carried out and compared with experimental data. The HOMO and LUMO analysis is used to determine the charge transfer within the molecule. The stability of the molecule arising from hyper-conjugative interactions and charge delocalization has been analysed using NBO analysis. First hyperpolarizability is calculated in order to find its role in non-linear optics. Besides molecular electrostatic potential (MEP), global reactivity descriptors, thermodynamic properties, and Mullikan charge analysis of the title compound were computed with the same method in gas phase, theoretically. Further, employing combination of DFT calculations and molecular dynamics (MD) simulations, we have investigated in detail reactive properties of the title molecule. Investigation of local reactive properties encompassed calculations of average local ionization energies (ALIE) and Fukui functions. Stability in water has been investigated by calculations of radial distribution functions (RDF), while sensitivity towards the mechanism of autoxidation has been investigated by calculations of bond dissociation energies (BDE). The docked ligand forms a stable complex with human alpha9 nicotinic acetylcholine receptor antagonist and can be a lead

  17. The use of fluorescent probes in the study of reactive oxygen species in pancreatic cancer cells.

    Science.gov (United States)

    Dinnen, Richard D; Mao, Yuehua; Fine, Robert L

    2013-01-01

    The use of fluorescent probes can be an easy and quick method to analyze whether or not reactive oxygen species (ROS) are involved in a particular cellular process or the result of a particular drug treatment. ROS activate a variety of cell signaling and death pathways including apoptosis and necrosis (Raha and Robinson. Am J Med Gen 106:62-70, 2001). Here we describe a number of different probes, their specificities, advantages and limitations, as well as useful techniques important for their use.

  18. Study on offshore wind farm integration mode and reactive power compensation

    Energy Technology Data Exchange (ETDEWEB)

    Bian, Xiaoyan; Hong, Lijun; Fu, Yang [Shanghai Univ. of Electrical Power (China). Power and Automation Engineering Dept.

    2013-07-01

    Two typical offshore wind farm grid-connected modes are introduced and dynamic characteristics under their modes are compared from the simulation by PSS/E. The result shows that offshore wind farm with VSC-HVDC has better dynamic characteristics on fault isolation, reactive power compensation, and fault ride through ability. In addition, STATCOM has been applied to the offshore wind farm, the simulation results indicates that it can improve the bus voltage stability in fault and maintain the voltage level under a small perturbation.

  19. NMR as a tool for kinetic studies: application to the assessment of organo tin reactivity

    Energy Technology Data Exchange (ETDEWEB)

    Fouquet, E.; Roulet, T. [Bordeaux-1 Univ., 33 - Talence (France); Pianet, I. [Bordeaux-1 Univ., 33 -Talence (France) CNRS, Centre d`Etudes Structurales et d`Analyse des Molecules Organiques; Willem, R. [Brussels University (VUB), Brussels (Belgium)

    1998-02-01

    There is a growing interest for the research of an answer to the environmental problems related to the industrial use of tetra organo tins. An interesting alternative would be to develop the chemistry of mono organo tins because of their lower toxicity and of the easy removal of ``inorganic`` tin side products. In this work, halogen exchange rates are measured for various mono organo tins with NMR techniques (EXSY spectra and 1 D {sup 119} Sn NMR), and an exchange mechanism is proposed. A correlation between kinetic data and the reactivity of the mono organo tins is then exemplified with radical allylic transfer and palladium catalyzed coupling reactions. (authors) 14 refs.

  20. C-reactive protein, insulin resistance and risk of cardiovascular disease: a population-based study

    DEFF Research Database (Denmark)

    Jeppesen, Jørgen; Hansen, Tine Willum; Olsen, Michael H

    2008-01-01

    ischaemic heart disease and nonfatal stroke, amounted to 222 cases. In Cox proportional-hazard models, adjusted for age, sex, smoking habit, total cholesterol, waist circumference, levels of triglycerides and high-density lipoprotein-cholesterol, systolic and diastolic blood pressures, physical activity......BACKGROUND: C-reactive protein (CRP), a marker of inflammation, and insulin resistance (IR), a metabolic disorder, are closely related. CRP and IR have both been identified as significant risk factors of cardiovascular disease (CVD) after adjustment for conventional CVD risk factors...

  1. Measurements of high-pressure steam-water enthalpy/void migration in unequally heated horizontal twin subchannels

    Energy Technology Data Exchange (ETDEWEB)

    Sutradhar, S.C. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)]. E-mail: sutradhars@aecl.ca; Yin, S.T. [Consultant, Toronto, Ontario (Canada)]. E-mail: yinst@sympatico.ca; Tain, R.M. [Industrial Technology Research Inst., Chutung, Hsinchu, Taiwan (China)]. E-mail: rtain@itri.org.tw

    2006-07-01

    An experimental study of enthalpy/void migration in two interconnected, unequally heated horizontal subchannels was conducted using high-pressure steam-water as the operating medium. The cross-sectional geometry of the twin subchannels simulated two adjacent, top-to-bottom aligned inner subchannels of a 37-element CANDU fuel bundle. The effect of unequal heating on enthalpy/void migration was measured using three different heat flux ratios of 1.00, 1.11 and 1.21, with the higher heat flux in the top subchannel. The test results indicated that under similar flow conditions, the unequal heat flux set-up enhanced the enthalpy/void migration from the bottom to the top subchannel compared to the equal heat flux set up. This study quantifies and characterizes the buoyancy-induced enthalpy/void migration between two interconnected horizontal subchannels subject to different heat fluxes. The database will be used to validate and improve the flow-mixing models in subchannel codes. (author)

  2. Comparative Studies on Dyeability with Direct, Acid and Reactive Dyes after Chemical Modification of Jute with Mixed Amino Acids Obtained from Extract of Waste Soya Bean Seeds

    Science.gov (United States)

    Bhaumik, Nilendu Sekhar; Konar, Adwaita; Roy, Alok Nath; Samanta, Ashis Kumar

    2017-06-01

    Jute fabric was treated with mixed natural amino acids obtained from waste soya bean seed extract for chemical modification of jute for its cataionization and to enhance its dyeability with anionic dyes (like direct, reactive and acid dye) as well enabling soya modified jute for salt free dyeing with anionic reactive dyes maintaining its eco-friendliness. Colour interaction parameters including surface colour strength were assessed and compared for both bleached and soya-modified jute fabric for reactive dyeing and compared with direct and acid dye. Improvement in K/S value (surface colour strength) was observed for soya-modified jute even in absence of salt applied in dye bath for reactive dyes as well as for direct and acid dyes. In addition, reactive dye also shows good dyeability even in acid bath in salt free conditions. Colour fastness to wash was evaluated for bleached and soya-modified jute fabric after dyeing with direct, acid and reactive dyes are reported. Treatment of jute with soya-extracted mixed natural amino acids showed anchoring of some amino/aldemine groups on jute cellulosic polymer evidenced from Fourier Transform Infra-Red (FTIR) Spectroscopy. This amino or aldemine group incorporation in bleached jute causes its cationization and hence when dyed in acid bath for reactive dye (instead of conventional alkali bath) showed dye uptake for reactive dyes. Study of surface morphology by Scanning Electron Microscopy (SEM) of said soya-modified jute as compared to bleached jute was studied and reported.

  3. Comparative Studies on Dyeability with Direct, Acid and Reactive Dyes after Chemical Modification of Jute with Mixed Amino Acids Obtained from Extract of Waste Soya Bean Seeds

    Science.gov (United States)

    Bhaumik, Nilendu Sekhar; Konar, Adwaita; Roy, Alok Nath; Samanta, Ashis Kumar

    2017-12-01

    Jute fabric was treated with mixed natural amino acids obtained from waste soya bean seed extract for chemical modification of jute for its cataionization and to enhance its dyeability with anionic dyes (like direct, reactive and acid dye) as well enabling soya modified jute for salt free dyeing with anionic reactive dyes maintaining its eco-friendliness. Colour interaction parameters including surface colour strength were assessed and compared for both bleached and soya-modified jute fabric for reactive dyeing and compared with direct and acid dye. Improvement in K/S value (surface colour strength) was observed for soya-modified jute even in absence of salt applied in dye bath for reactive dyes as well as for direct and acid dyes. In addition, reactive dye also shows good dyeability even in acid bath in salt free conditions. Colour fastness to wash was evaluated for bleached and soya-modified jute fabric after dyeing with direct, acid and reactive dyes are reported. Treatment of jute with soya-extracted mixed natural amino acids showed anchoring of some amino/aldemine groups on jute cellulosic polymer evidenced from Fourier Transform Infra-Red (FTIR) Spectroscopy. This amino or aldemine group incorporation in bleached jute causes its cationization and hence when dyed in acid bath for reactive dye (instead of conventional alkali bath) showed dye uptake for reactive dyes. Study of surface morphology by Scanning Electron Microscopy (SEM) of said soya-modified jute as compared to bleached jute was studied and reported.

  4. The effect of inactivity on reactive hyperaemia in the human calf: a study with strain gauge plethysmography.

    Science.gov (United States)

    Kroese, A J

    1977-02-01

    In order to study the influence of muscular inactivity on reactive hyperaemia, postischaemic blood flow was measued with strain gauge plethysmography in the calf of twenty-nine patients, who had been treated with a plaster cast for a trauma of the lower limb. The contralateral leg served as a comparison. In all but two patients postischaemic maximal flow was lower in the immobilized calf. A negative correlation existed between maximal flow and the duration of immobilization. In the course of 6 weeks after removal of the cast, the difference in maximal flow between both sides became insignificant. Venous volume and venous emptying were not different in the two limbs. The effect of inactivity on reactive hyperaemic response may be explained by an effect of inactivity on the arterioles, muscle atrophy, a decrease in capillarization and in oxidative capacity of the muscle fibres. It is concluded that inactivity and atrophy of the lower limb musculature in patients with peripheral arterial disease may be a contributing factor to the low reactive hyperaemic response in the calf of such patients.

  5. Effect of chemical degradation on fluxes of reactive compounds – a study with a stochastic Lagrangian transport model

    Directory of Open Access Journals (Sweden)

    J. Rinne

    2012-06-01

    Full Text Available In the analyses of VOC fluxes measured above plant canopies, one usually assumes the flux above canopy to equal the exchange at the surface. Thus one assumes the chemical degradation to be much slower than the turbulent transport. We used a stochastic Lagrangian transport model in which the chemical degradation was described as first order decay in order to study the effect of the chemical degradation on above canopy fluxes of chemically reactive species. With the model we explored the sensitivity of the ratio of the above canopy flux to the surface emission on several parameters such as chemical lifetime of the compound, friction velocity, stability, and canopy density. Our results show that friction velocity and chemical lifetime affected the loss during transport the most. The canopy density had a significant effect if the chemically reactive compound was emitted from the forest floor. We used the results of the simulations together with oxidant data measured during HUMPPA-COPEC-2010 campaign at a Scots pine site to estimate the effect of the chemistry on fluxes of three typical biogenic VOCs, isoprene, α-pinene, and β-caryophyllene. Of these, the chemical degradation had a major effect on the fluxes of the most reactive species β-caryophyllene, while the fluxes of α-pinene were affected during nighttime. For these two compounds representing the mono- and sesquiterpenes groups, the effect of chemical degradation had also a significant diurnal cycle with the highest chemical loss at night. The different day and night time loss terms need to be accounted for, when measured fluxes of reactive compounds are used to reveal relations between primary emission and environmental parameters.

  6. How Hyperarousal and Sleep Reactivity Are Represented in Different Adult Age Groups: Results from a Large Cohort Study on Insomnia.

    Science.gov (United States)

    Altena, Ellemarije; Chen, Ivy Y; Daviaux, Yannick; Ivers, Hans; Philip, Pierre; Morin, Charles M

    2017-04-14

    Hyperarousal is a 24-h state of elevated cognitive and physiological activation, and is a core feature of insomnia. The extent to which sleep quality is affected by stressful events-so-called sleep reactivity-is a vulnerability factor for developing insomnia. Given the increasing prevalence of insomnia with age, we aimed to investigate how hyperarousal and sleep reactivity were related to insomnia severity in different adult age groups. Data were derived from a large cohort study investigating the natural history of insomnia in a population-based sample (n = 1693). Baseline data of the Arousal Predisposition Scale (APS) and Ford Insomnia Response to Stress Test (FIRST) were examined across age and sleep/insomnia subgroups: 25-35 (n = 448), 35-45 (n = 528), and 45-55 year olds (n = 717); good sleepers (n = 931), individuals with insomnia symptoms (n = 450), and individuals with an insomnia syndrome (n = 312). Results from factorial analyses of variance (ANOVA) showed that APS scores decreased with increasing age, but increased with more severe sleep problems. FIRST scores were not significantly different across age groups, but showed the same strong increase as a function of sleep problem severity. The findings indicate that though arousal predisposition and sleep reactivity increase with more severe sleep problems, only arousal decreases with age. How arousing events affect an individual during daytime thus decreases with age, but how this arousal disrupts sleep is equivalent across different adult age groups. The main implication of these findings is that treatment of insomnia could be adapted for different age groups and take into consideration vulnerability factors such as hyperarousal and stress reactivity.

  7. X-ray study of reactive ion etch damage to silicon

    Science.gov (United States)

    Nemiroff, M.; Stuber, M.; Troutt, R.; Gerber, D.; Mittal, S.

    1987-11-01

    Contact resistance measurements, x-ray double-crystal diffraction, and Auger electron spectroscopy were used to evaluate reactive ion etch (RIE) damage to silicon wafers. Wafers were exposed to plasmas at different powers with gas mixtures of CHF3/O2 and O2 only. The CHF3/O2 mixture was typical of a gas mixture used for etching contacts to silicon. The O2 alone was used as a damaging, bombarding gas. Some oxidation of silicon occurs during the O2 bombardment. However, O2 was used to determine the effects of ion bombardment at conditions similar to those that occur during RIE etching of contacts. It has been found that the depth of damage to the underlying silicon increases with cathode bias and that at -550 V the damage is 200-250 Å deep. The damage at -550 V consists of two layers: one is an amorphous and/or polycrystalline silicon layer at the surface 100-125 Å thick. The surface layer contains impurities as a result of the reactive ion etch process. The second single-crystal dilated layer, 100-125 Å thick, lies beneath the amorphous/poly Si layer. The thickness of these layers is the same when either CHF3/O2 or O2 alone are used as the etchant gases.

  8. Oxytocin administration attenuates stress reactivity in borderline personality disorder: a pilot study.

    Science.gov (United States)

    Simeon, D; Bartz, J; Hamilton, H; Crystal, S; Braun, A; Ketay, S; Hollander, E

    2011-10-01

    Oxytocin has known stress-reducing and attachment-enhancing effects. We thus hypothesized that oxytocin would attenuate emotional and hormonal responses to stress in borderline personality disorder (BPD). Fourteen BPD and 13 healthy control (HC) adults received 40 IU intranasal oxytocin or placebo in double-blind randomized order followed by the Trier Social Stress Test. Subjective dysphoria (Profile of Mood Changes) and plasma cortisol levels were measured. Childhood trauma history, attachment style, and self-esteem were also rated. A significant "Group × Drug × Time" interaction effect for dysphoria (p=.04) reflected a proportionately greater attenuation of stress-induced dysphoria in the BPD group after oxytocin administration. Additionally, a marginally significant "Group × Drug" interaction effect for cortisol (p=.10) reflected a tendency toward greater attenuation of the stress-induced cortisol surge in the BPD group after oxytocin administration. In the combined sample, the oxytocin-placebo difference in the emotional stress reactivity was significantly predicted by childhood trauma alone (p=.037) and combined with self-esteem (p=.030), whereas the oxytocin-placebo difference in cortisol stress reactivity was predicted only by insecure attachment (p=.013). Results suggest that oxytocin may have a beneficial impact on emotional regulation in BPD, which merits further investigation and could have important treatment implications. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. Synthesis and characterization of core-shell acrylate based latex and study of its reactive blends.

    Science.gov (United States)

    Liu, Xiang; Fan, Xiao-Dong; Tang, Min-Feng; Nie, Ying

    2008-03-01

    Techniques in resin blending are simple and efficient method for improving the properties of polymers, and have been used widely in polymer modification field. However, polymer latex blends such as the combination of latexes, especially the latexes with water-soluble polymers, were rarely reported. Here, we report a core-shell composite latex synthesized using methyl methacrylate (MMA), butyl acrylate (BA), 2-ethylhexyl acrylate (EHA) and glycidyl methacrylate (GMA) as monomers and ammonium persulfate and sodium bisulfite redox system as the initiator. Two stages seeded semi-continuous emulsion polymerization were employed for constructing a core-shell structure with P(MMA-co-BA) component as the core and P(EHA-co-GMA) component as the shell. Results of Transmission Electron Microscopy (TEM) and Dynamics Light Scattering (DLS) tests confirmed that the particles obtained are indeed possessing a desired core-shell structural character. Stable reactive latex blends were prepared by adding the latex with waterborne melamine-formaldehyde resin (MF) or urea-formaldehyde resin (UF). It was found that the glass transition temperature, the mechanical strength and the hygroscopic property of films cast from the latex blends present marked enhancements under higher thermal treatment temperature. It was revealed that the physical properties of chemically reactive latexes with core-shell structure could be altered via the change of crosslinking density both from the addition of crosslinkers and the thermal treatment.

  10. Synthesis and Characterization of Core-Shell Acrylate Based Latex and Study of Its Reactive Blends

    Directory of Open Access Journals (Sweden)

    Ying Nie

    2008-03-01

    Full Text Available Techniques in resin blending are simple and efficient method for improving the properties of polymers, and have been used widely in polymer modification field. However, polymer latex blends such as the combination of latexes, especially the latexes with water-soluble polymers, were rarely reported. Here, we report a core-shell composite latex synthesized using methyl methacrylate (MMA, butyl acrylate (BA, 2-ethylhexyl acrylate (EHA and glycidyl methacrylate (GMA as monomers and ammonium persulfate and sodium bisulfite redox system as the initiator. Two stages seeded semi-continuous emulsion polymerization were employed for constructing a core-shell structure with P(MMA-co-BA component as the core and P(EHA-co-GMA component as the shell. Results of Transmission Electron Microscopy (TEM and Dynamics Light Scattering (DLS tests confirmed that the particles obtained are indeed possessing a desired core-shell structural character. Stable reactive latex blends were prepared by adding the latex with waterborne melamine-formaldehyde resin (MF or urea-formaldehyde resin (UF. It was found that the glass transition temperature, the mechanical strength and the hygroscopic property of films cast from the latex blends present marked enhancements under higher thermal treatment temperature. It was revealed that the physical properties of chemically reactive latexes with core-shell structure could be altered via the change of crosslinking density both from the addition of crosslinkers and the thermal treatment.

  11. Growth of organic films on semiconductor surfaces: Fundamental reactivity studies and molecular layer deposition involving isocyanates and isothiocyanates

    Science.gov (United States)

    Loscutoff, Paul W.

    The continued pursuit of smaller device dimensions by the semiconductor industry has led to an increased interest in functional organic films. Organics have great potential as advanced materials, owing to the versatility of organic moieties and vast knowledge base of organic reactivity. In order to implement organic films into semiconductor devices, the inorganic/organic hybrid interfaces must be investigated, so that the reactivity at these pivotal features is well-known. In this work organic films are studied in two environments: the Ge(100)-2x1 surface and the SiO2 surface. The reconstructed Ge(100)-2x1 surface offers a well-defined substrate, ideal for fundamental reactivity studies. Organic reactants are deposited under ultrahigh vacuum conditions, allowing reactions between gas-phase organic molecules and the surface to be isolated and analyzed by in situ spectroscopic techniques. By use of infrared (IR) spectroscopy, x-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) modeling, we investigate the reactivity of phenyl and tert-butyl isocyanate and isothiocyanate at the Ge(100)-2x1 surface. The isocyanate and isothiocyanate moieties are both highly reactive groups consisting of a cumulated double bond containing two heteroatoms, allowing for many potential products with the Ge surface. We find that dative bonding through the heteroatoms plays an important role in the surface reactions, functioning as either reaction intermediates or final products depending on the adsorbate. Various cycloaddition products are also observed at the surface, with prominent reactivity trends resulting from the differences in oxygen and sulfur reactivity. In order to study the practical implementation of organic films, molecular layer deposition (MLD) reactions are studied on the hydroxlyated SiO 2 surface. MLD is a layer-by-layer technique, where films are deposited one molecular unit at a time, allowing for film tailorability and composition control down to

  12. Reactive arthritis.

    Science.gov (United States)

    Keat, A

    1999-01-01

    Reactive arthritis is one of the spondyloarthropathy family of clinical syndromes. The clinical features are those shared by other members of the spondyloarthritis family, though it is distinguished by a clear relationship with a precipitating infection. Susceptibility to reactive arthritis is closely linked with the class 1 HLA allele B27; it is likely that all sub-types pre-dispose to this condition. The link between HLA B27 and infection is mirrored by the development of arthritis in HLA B27-transgenic rats. In this model, arthritis does not develop in animals maintained in a germ-free environment. Infections of the gastrointestinal, genitourinary and respiratory tract appear to provoke reactive arthritis and a wide range of pathogens has now been implicated. Although mechanistic parallels may exist, reactive arthritis is distinguished from Lyme disease, rheumatic fever and Whipple's disease by virtue of the distinct clinical features and the link with HLA B27. As in these conditions both antigens and DNA of several micro-organisms have been detected in joint material from patients with reactive arthritis. The role of such disseminated microbial elements in the provocation or maintenance of arthritis remains unclear. HLA B27-restricted T-cell responses to microbial antigens have been demonstrated and these may be important in disease pathogenesis. The importance of dissemination of bacteria from sites of mucosal infection and their deposition in joints has yet to be fully understood. The role of antibiotic therapy in the treatment of reactive arthritis is being explored; in some circumstances, both the anti-inflammatory and anti-microbial effects of certain antibiotics appear to be valuable. The term reactive arthritis should be seen as a transitory one, reflecting a concept which may itself be on the verge of replacement, as our understanding of the condition develops. Nevertheless it appropriately describes arthritis that is associated with demonstrable

  13. Molecular dynamics simulations of void defects in the energetic material HMX.

    Science.gov (United States)

    Duan, Xiao Hui; Li, Wen Peng; Pei, Chong Hua; Zhou, Xiao Qing

    2013-09-01

    A molecular dynamics (MD) simulation was carried out to characterize the dynamic evolution of void defects in crystalline octahydro-1, 3, 5, 7-tetranitro-1, 3, 5, 7-tetrazocine (HMX). Different models were constructed with the same concentration of vacancies (10 %) to discuss the size effects of void. Energetic ground state properties were determined by annealing simulations. The void formation energy per molecule removed was found to be 55-63 kcal/mol(-1), and the average binding energy per molecule was between 32 and 34 kcal/mol(-1) according to the change in void size. Voids with larger size had lower formation energy. Local binding energies for molecules directly on the void surface decreased greatly compared to those in defect-free lattice, and then gradually increased until the distance away from the void surface was around 10 Å. Analysis of 1 ns MD simulations revealed that the larger the void size, the easier is void collapse. Mean square displacements (MSDs) showed that HMX molecules that had collapsed into void present liquid structure characteristics. Four unique low-energy conformers were found for HMX molecules in void: two whose conformational geometries corresponded closely to those found in HMX polymorphs and two, additional, lower energy conformers that were not seen in the crystalline phases. The ratio of different conformers changed with the simulated temperature, in that the ratio of α conformer increased with the increase in temperature.

  14. On the formation of voids in internal tin Nb3Sn superconductors

    CERN Document Server

    Scheuerlein, C; Haibel, A

    2007-01-01

    In this article we describe three void growth mechanisms in Nb3Sn strands of the internal tin design on the basis of combined synchrotron micro-tomography and x-ray diffraction measurements during in-situ heating cycles. Initially void growth is driven by a reduction of void surface area by void agglomeration. The main void volume increase is caused by density changes during the formation of Cu3Sn in the strand. Subsequent transformation of Cu-Sn intermetallics into the lower density a-bronze reduces the void volume again. Long lasting temperature ramps and isothermal holding steps can neither reduce the void volume nor improve the chemical strand homogeneity prior to the superconducting A15 phase nucleation and growth.

  15. Discovery of an extremely gas rich dwarf triplet near the centre of the Lynx-Cancer void

    Science.gov (United States)

    Chengalur, J. N.; Pustilnik, S. A.

    2013-01-01

    The Giant Metrewave Radio Telescope (GMRT) H i observations, done as part of an ongoing study of dwarf galaxies in the Lynx-Cancer void, resulted in the discovery of a triplet of extremely gas rich galaxies located near the centre of the void. The triplet members SDSS J0723+3621, SDSS J0723+3622 and SDSS J0723+3624 have absolute magnitudes MB of -14.2, -11.9 and -9.7 and M(H i)/LB of ˜2.9, ˜10 and ˜25, respectively. The gas mass fractions, as derived from the Sloan Digital Sky Survey (SDSS) photometry and the GMRT data, are 0.93, 0.997 and 0.997, respectively. The faintest member of this triplet, SDSS J0723+3624, is one of the most gas rich galaxies known. We find that all three galaxies deviate significantly from the Tully-Fisher relation, but follow the baryonic Tully-Fisher relation. All three galaxies also have a baryon fraction that is significantly smaller than the cosmic baryon fraction. For the largest galaxy in the triplet, this is in contradiction to numerical simulations. The discovery of this very unique dwarf triplet lends further support to the idea that the void environment is conducive to the formation of galaxies with unusual properties. These observations provide further motivation to do deep searches of voids for a `hidden' very gas rich galaxy population with MB ≳ -11.

  16. Effect of pelvic floor muscle exercise on pelvic floor muscle activity and voiding functions during pregnancy and the postpartum period.

    Science.gov (United States)

    Kahyaoglu Sut, Hatice; Balkanli Kaplan, Petek

    2016-03-01

    The aim of this study was to investigate the effects of pelvic floor muscle exercise during pregnancy and the postpartum period on pelvic floor muscle activity and voiding functions. Pregnant women (n = 60) were randomly assigned into two groups (Training [n = 30] and Control [n = 30]) using a computer-based system. Pelvic floor muscle strength was measured using a perineometry device. Urinary symptoms were measured using the Urinary Distress Inventory (UDI-6), Incontinence Impact Questionnaire (IIQ-7), and the Overactive Bladder Questionnaire (OAB-q). Voiding functions were measured using uroflowmetry and 3-day voiding diaries. Measurements were obtained at week 28, weeks 36-38 of pregnancy, and postpartum weeks 6-8. Pelvic floor muscle strength significantly decreased during the pregnancy (P pelvic floor muscle strength improvement was significantly higher in the Training group compared to the Control group (P  0.05). However, UDI-6, coping, concern, and total scores of OAB-q were significantly decreased during weeks 36-38 of pregnancy in the Control group (P pelvic floor muscle strength, urinary symptoms, quality of life, and voiding functions. Pelvic floor muscle exercises applied during pregnancy and the postpartum period increase pelvic floor muscle strength and prevent deterioration of urinary symptoms and quality of life in pregnancy. © 2015 Wiley Periodicals, Inc.

  17. Quantum dynamics study of energy requirement on reactivity for the HBr + OH reaction with a negative-energy barrier

    Science.gov (United States)

    Wang, Yuping; Li, Yida; Wang, Dunyou

    2017-01-01

    A time-dependent, quantum reaction dynamics approach in full dimensional, six degrees of freedom was carried out to study the energy requirement on reactivity for the HBr + OH reaction with an early, negative energy barrier. The calculation shows both the HBr and OH vibrational excitations enhance the reactivity. However, even this reaction has a negative energy barrier, the calculation shows not all forms of energy are equally effective in promoting the reactivity. On the basis of equal amount of total energy, the vibrational energies of both the HBr and OH are more effective in enhancing the reactivity than the translational energy, whereas the rotational excitations of both the HBr and OH hinder the reactivity. The rate constants were also calculated for the temperature range between 5 to 500 K. The quantal rate constants have a better slope agreement with the experimental data than quasi-classical trajectory results.

  18. Intercomparison of OH and OH reactivity measurements in a high isoprene and low NO environment during the Southern Oxidant and Aerosol Study (SOAS)

    Science.gov (United States)

    Sanchez, Dianne; Jeong, Daun; Seco, Roger; Wrangham, Ian; Park, Jeong-Hoo; Brune, William H.; Koss, Abigail; Gilman, Jessica; de Gouw, Joost; Misztal, Pawel; Goldstein, Allen; Baumann, Karsten; Wennberg, Paul O.; Keutsch, Frank N.; Guenther, Alex; Kim, Saewung

    2018-02-01

    We intercompare OH and OH reactivity datasets from two different techniques, chemical ionization mass spectrometry (CIMS) and laser-induced fluorescence (LIF) in a high isoprene and low NO environment in a southeastern US forest during the Southern Oxidant and Aerosol Study (SOAS). An LIF instrument measured OH and OH reactivity at the top of a tower, a CIMS instrument measured OH at the top of the tower, and a CIMS based comparative reactivity method (CRM-CIMS) instrument deployed at the base of the tower measured OH reactivity. Averaged diel variations of OH and OH reactivity from these datasets agree within analytical uncertainty and correlations of LIF versus CIMS for OH and OH reactivity have slopes of 0.65 and 0.97, respectively. However, there are systematic differences between the measurement datasets. The CRM-CIMS measurements of OH reactivity were ∼16% lower than those by the LIF technique in the late afternoon. We speculate that it is caused by losses in the sampling line down to the CRM-CIMS instrument. On the other hand, we could not come up with a reasonable explanation for the difference in the LIF and CIMS OH datasets for early morning and late afternoon when OH is below 1 × 106 molecules cm-3. Nonetheless, results of this intercomparison exercise strengthen previous publications from the field site on OH concentrations and atmospheric reactivity.

  19. Diverse Studies in the Reactivated NASA/Ames Radiation Facility: From Shock Layer Spectroscopy to Thermal Protection System Impact

    Science.gov (United States)

    Miller, Robert J.; Hartman, G. Joseph (Technical Monitor)

    1994-01-01

    NASA/Ames' Hypervelocity Free-Flight Radiation Facility has been reactivated after having been decommissioned for some 15 years, first tests beginning in early 1994. This paper discusses two widely different studies from the first series, one involving spectroscopic analysis of model shock-layer radiation, and the other the production of representative impact damage in space shuttle thermal protection tiles for testing in the Ames arc-jet facilities. These studies emphasize the interorganizational and interdisciplinary value of the facility in the newly-developing structure of NASA.

  20. Determination of Susceptibility to Intergranular Corrosion of UNS 31803 Type Duplex Stainless Steel by Electrochemical Reactivation Method: A Comparative Study

    OpenAIRE

    Mehmet Emin Arıkan; Rafet Arıkan; Mustafa Doruk

    2012-01-01

    In the present study as in our previous studies (Arikan and Doruk, 2008 and Arikan et al., 2012), similar specimens taken from a hot rolled cylindrical duplex stainless steel (DSS) bar with 22% Cr grade were solution annealed at 1050°C and then aged at 800∘C from 100 to 31622 min for sensitization treatment. Double loop electrochemical potentiodynamic reactivation and standard weight loss immersion acid tests were conducted. The solution annealed samples were found unsensitized. The samples a...