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Sample records for annulus spacer mobility

  1. Generic assessment of tight-fitting annulus spacer mobility

    International Nuclear Information System (INIS)

    Robertson, J.; Micuda, L.; Van Den Brekel, N.

    2006-01-01

    This paper provides a generic assessment of the mobility of tight-fitting fuel channel annulus spacers in OPG and Bruce Power nuclear units. This assessment is applicable to all tight-fitting annulus spacers, including those used in the original fuel channel installation (Darlington Units 1-4, retubed Pickering Units 1-4, and Bruce Unit 8) and as a result of single fuel channel replacements (SFCR) (Pickering Units 5-8, Bruce Units 3-7). Tight-fitting annulus spacers were designed not to move. Pressure tube to calandria tube contact analyses, and the associated blister susceptibility assessments, have assumed that these tight-fitting spacers remain at the pre-service installed locations. Given the importance of this assumption, the technical basis for the expectation that tight-fitting annulus spacers do not move significantly from their pre-service locations, relative to the pressure tube, was reviewed in detail. The review also assessed the inspection data, comparing spacer locations from in-service and pre-service inspections. The review has concluded that tight-fitting spacers do not move sufficiently to necessitate a postulated spacer movement in fuel channel contact analyses. The paper describes the background of this issue, briefly reviews the experimental programs used to qualify the positional stability of the tight-fitting spacer design, and evaluates the current database of in-service spacer location inspection information to demonstrate that no significant movement relative to the pressure tube has been observed. (author)

  2. Detection and repositioning of tight fighting annulus spacers in CANDU® fuel channels

    Energy Technology Data Exchange (ETDEWEB)

    Hersak, G.; Kittmer, A. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); Goszczynski, J. [Candu Energy Inc., Mississauga, Ontario (Canada); Kazimer, D. [Bruce Power, Tiverton, Ontario (Canada)

    2014-06-15

    The latest generation of CANDU® reactors has been constructed with tight-fitting annulus spacers to maintain the annular gap between the inner pressure tubes and the outer calandria tubes. These spacers cannot be detected and repositioned with the existing Spacer Location and Repositioning (SLAR) process, which is designed to work with loose-fitting annulus spacers. There is currently no established technology to detect and reposition tight-fitting annulus spacers. Atomic Energy of Canada Limited has been performing research and development to locate and move tight-fitting annulus spacers using Modal Detection and Repositioning (MODAR) technology since 2005 and is currently working in collaboration with Candu Energy and Bruce Power on a production system to be deployed for an In-reactor demonstration in the next year. The MODAR technology uses controlled vibrations on a short, isolated length of pressure tube to locate and reposition tight-fitting annulus spacers. MODAR technology will allow the utilities to demonstrate fuel channel integrity to the regulator and obtain approval for additional years of reactor operation. This paper briefly describes the technology and provides an overview of the tool testing and development. (author)

  3. An examination of the influence of spacers on burnout in an annulus cooled by the upflow of Freon-12

    International Nuclear Information System (INIS)

    Ilic, V.

    1975-04-01

    To evaluate the spacer influence on burnout, tests were carried out in Freon-12 at 1.04 MPa (abs.) test section inlet pressure with an internally heated annulus 2743 mm long by 14.4 mm heater diameter, the outer tube (shroud) having a bore of 22.1 mm. The inner rod (heater) was located centrally to the shroud by spacers and their configuration was changed for each test. Comparison of the results with those obtained with a test section having no spacers indicated that spacers can increase burnout power up to 75 per cent, decrease it, or show no effect at all, depending on the combination of the inlet temperature and mass velocity. If the spacers were streamlined, removed from the upstream portion of the heater or relocated farther upstream from the downstream end of the heater, there was a considerably reduced effect on the test section performance. (author)

  4. Measurements of the Effects of Spacers on the Burnout Conditions for Flow of Boiling Water in a Vertical Annulus and a Vertical 7-Rod Cluster

    International Nuclear Information System (INIS)

    Becker, Kurt M.; Hernborg, G.

    1964-11-01

    The present report deals with measurements of the effects of spacers on the burnout conditions in a vertical annulus and a vertical 7-rod cluster. The following ranges of variables were studied and 162 burnout measurements were obtained. Pressure p = 31 kg/cm; Inlet sub-cooling 35 sub 2 ; Mass velocity 94 2 /s; Burnout steam quality 0.10 BO < 0.56. The experimental results showed that the type of spacers employed during the present investigation had negligible effects on the burnout conditions and that the measured burnout heat fluxes could be predicted within ± 5 per cent by means of the correlation by Becker et al for flow in smooth channels

  5. Recovery of knee mobility after a static or mobile spacer in total knee infection

    NARCIS (Netherlands)

    Brunnekreef, J.J.; Hannink, G.; Mde, W. Malefijt

    2013-01-01

    The purpose of the study was to compare the recovery of knee mobility after two-stage revision of an infected total knee arthroplasty using a static or mobile spacer. At 12 months follow-up, none of the patients had a recurrent infection of their new prosthesis. Knee flexion was lower in the static

  6. Increase of the electron mobility in HEMT heterostructures with composite spacers containing AlAs nanolayers

    Energy Technology Data Exchange (ETDEWEB)

    Vinichenko, A. N., E-mail: vanaxel@gmail.com; Gladkov, V. P.; Kargin, N. I.; Strikhanov, M. N.; Vasil’evskii, I. S. [National Research Nuclear University “MEPhI” (Russian Federation)

    2014-12-15

    The effect of the hybridization of quantum states on electron transport in a two-barrier quantum well δ-doped through a spacer layer at the limit of heavy doping is shown theoretically and experimentally. A method for increasing the electron mobility in the quantum well by suppressing the tunnel coupling with the donor region through the introduction of an AlAs nanobarrier into the spacer layer is proposed. It is experimentally shown that, in the samples with a shallow quantum well, the AlAs nanobarrier introduced into the spacer layer provides a larger than threefold increase in the electron mobility at low temperatures.

  7. Biarticular total femur spacer for massive femoral bone loss: the mobile solution for a big problem

    Directory of Open Access Journals (Sweden)

    Pablo Sanz-Ruiz, PhD, MD

    2018-03-01

    Full Text Available Bone cement spacers loaded with antibiotic are the gold standard in septic revision. However, the management of massive bone defects constitutes a surgical challenge, requiring the use of different nails, expensive long stems, or cement-coated tumor prostheses for preparing the spacer. In most cases, the knee joint must be sacrificed. We describe a novel technique for preparing a biarticular total femur spacer with the help of a trochanteric nail coated with antibiotic loaded cement, allowing mobility of the hip and knee joints and assisted partial loading until second step surgery. This technique is helpful to maintain the length of the leg, prevent soft tissue contracture, and help eradicate the infection preserving the patient comfort and autonomy while waiting to receive total femoral replacement.

  8. Biarticular total femur spacer for massive femoral bone loss: the mobile solution for a big problem.

    Science.gov (United States)

    Sanz-Ruiz, Pablo; Calvo-Haro, Jose Antonio; Villanueva-Martinez, Manuel; Matas-Diez, Jose Antonio; Vaquero-Martín, Javier

    2018-03-01

    Bone cement spacers loaded with antibiotic are the gold standard in septic revision. However, the management of massive bone defects constitutes a surgical challenge, requiring the use of different nails, expensive long stems, or cement-coated tumor prostheses for preparing the spacer. In most cases, the knee joint must be sacrificed. We describe a novel technique for preparing a biarticular total femur spacer with the help of a trochanteric nail coated with antibiotic loaded cement, allowing mobility of the hip and knee joints and assisted partial loading until second step surgery. This technique is helpful to maintain the length of the leg, prevent soft tissue contracture, and help eradicate the infection preserving the patient comfort and autonomy while waiting to receive total femoral replacement.

  9. Preventing Complications from High-Dose Rate Brachytherapy when Treating Mobile Tongue Cancer via the Application of a Modular Lead-Lined Spacer.

    Directory of Open Access Journals (Sweden)

    Shumei Murakami

    Full Text Available To point out the advantages and drawbacks of high-dose rate brachytherapy in the treatment of mobile tongue cancer and indicate the clinical importance of modular lead-lined spacers when applying this technique to patients.First, all basic steps to construct the modular spacer are shown. Second, we simulate and evaluate the dose rate reduction for a wide range of spacer configurations.With increasing distance to the source absorbed doses dropped considerably. Significantly more shielding was obtained when lead was added to the spacer and this effect was most pronounced on shorter (i.e. more clinically relevant distances to the source.The modular spacer represents an important addition to the planning and treatment stages of mobile tongue cancer using HDR-ISBT.

  10. Bumpy torus annulus startup

    International Nuclear Information System (INIS)

    Sperling, J.L.; Hamasaki, S.; Krall, N.A.

    1982-01-01

    In order that a stable bumpy torus plasma configuration can be attained, it is first necessary to irradiate the plasma with sufficient external power to cause annulus formation. To estimate the power required to initiate annuli, it is assumed that quasilinear electron-cyclotron heating by microwaves is the dominant electron heating mechanism. A scaling law for required microwave power is derived which shows that annulus formation is assisted by smaller cross-section areas, lower density, lower microwave frequency, and higher C-mode temperature. The scaling law is quantitatively evaluated for NBT, EBT-1, EBT-S, EBT-P, and EBT-R parameters. The resulting power estimates are consistent with the available microwave power in previous and present experiments. In larger projected bumpy tori, like EBT-P and EBT-R, it may be necessary to initiate annulus formation at densities which are lower than in the stable T-mode so that the necessary microwave power can be reduced to reasonably modest levels. It is suggested that instabilities as well as rf heating can aid the formation of bumpy torus electron annuli. Rf experiments on NBT and EBT-S would be beneficial in determining the capability of rf power to assist annulus startup

  11. Fuel spacer

    International Nuclear Information System (INIS)

    Nishida, Koji; Yokomizo, Osamu; Kanazawa, Toru; Kashiwai, Shin-ichi; Orii, Akihito.

    1992-01-01

    The present invention concerns a fuel spacer for a fuel assembly of a BWR type reactor and a PTR type reactor. Springs each having a vane are disposed on the side surface of a circular cell which supports a fuel rods. A vortex streams having a vertical component are formed by the vanes in the flowing direction of a flowing channel between adjacent cylindrical cells. Liquid droplets carried by streams are deposited on liquid membrane streams flowing along the fuel rod at the downstream of the spacer by the vortex streams. In view of the above, the liquid droplets can be deposited to the fuel rod without increasing the amount of metal of the spacer. Accordingly, the thermal margin of the fuel assembly can be improved without losing neutron economy. (I.N.)

  12. Vectorisation of agrochemicals via amino acid carriers: influence of the spacer arm structure on the phloem mobility of phenylpyrrole conjugates in the Ricinus system.

    Science.gov (United States)

    Marhadour, Sophie; Wu, Hanxiang; Yang, Wen; Marivingt-Mounir, Cécile; Bonnemain, Jean-Louis; Chollet, Jean-François

    2017-09-01

    Excessive agrochemical use poses significant threats to environmental safety and human health. Reducing pesticide use without reducing yield is necessary for sustainable agriculture. Therefore, we developed a vectorisation strategy to enhance agrochemical delivery through plant amino acid carriers. In addition to a fenpiclonil conjugate recently described, three new amino acid conjugates were synthesised by coupling fenpiclonil to an l-α-amino acid. Phloem mobility of these conjugates, which exhibit different structures of the spacer arm introduced between fenpiclonil and the α-amino acid function, was studied using the Ricinus model. Conjugate L-14, which contains a triazole ring with the shortest amino acid chain, showed the best phloem systemicity among the four conjugates. By contrast, removing the triazole ring in the spacer arm did not improve systemicity. L-14 exhibited phloem systemicity at all reported pH values (pH values from 5.0 to 6.5) of the foliar apoplast, while acidic derivatives of fenpiclonil were translocated only at pH values near 5.0. The conjugates were recognised by a pH-dependent transporter system and translocated at distance in the phloem. They exhibited a broader phloem systemicity than fenpiclonil acidic derivatives within the pH value range of the foliar apoplast. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  13. Spacer st4ructure

    International Nuclear Information System (INIS)

    Masetti, W.R.

    1978-01-01

    A spacer structure is described for maintaining a spaced relation between a plurality of generally parallel fuel rods within a housing in a nuclear reactor. The spacer structure is comprised of a grid pattern of ribs slotted to interlock with each other. The slots are arranged in such a way that when the ribs are welded to each other, the weld shrinkage is distributed uniformly in all directions to reduce or eliminate the amount of rework necessary in manufacturing the spacer structure

  14. Mixing vane grid spacer

    International Nuclear Information System (INIS)

    Patterson, J.F.; Galbraith, K.P.

    1978-01-01

    An improved mixing vane grid spacer having enhanced flow mixing capability by virtue of mixing vanes being positioned at welded intersecting joints of the spacer wherein each mixing vane has an opening or window formed therein substantially directly over the welded joint to provide improved flow mixing capability is described. Some of the vanes are slotted, depending on their particular location in the spacers. The intersecting joints are welded by initially providing consumable tabs at and within each window, which are consumed during the welding of the spacer joints

  15. Fouling resistant membrane spacers

    KAUST Repository

    Ghaffour, Noreddine

    2017-10-12

    Disclosed herein are spacers having baffle designs and perforations for efficiently and effectively separating one or more membrane layers a membrane filtration system. The spacer (504) includes a body (524) formed at least in part by baffles (520) that are interconnected, and the baffles define boundaries of openings or apertures (525) through a thickness direction of the body of the spacer. Alternatively or additionally, passages or perforations (526A, 526B) may be present in the spacer layer or baffles for fluid flow there through, with the passages and baffles having a numerous different shapes and sizes.

  16. Structural Stator Spacers

    DEFF Research Database (Denmark)

    Rasmussen, Peter Omand; Andreasen, Jens H.; Pijanowski, J. M.

    2001-01-01

    This paper presents a powerful new design aspect to reduce acoustic noise and vibration of electro-magnetic origin for electrical machines, by introducing improved slot wedges referred to as "Structural Stator Spacers". These spacers, by using a very stiff dielectric and non magnetic material, a ...

  17. Apparatus for steam generator tube wrapper spacer and support block removal

    International Nuclear Information System (INIS)

    Calhoun, G.L.; Cassette, A.J.

    1982-01-01

    A cutting torch is described that may be used to cut through the spacers and the support blocks in the annulus between the outer shell of a steam generator and a tube bundle wrapper. The torch is supported by a multi-section column made up of a number of interlocked separable aluminum channel sections carried by a motorized carriage movable vertically along a rack and guide member clamped to the wrapper

  18. Laguna Verde annulus pressurization loads evaluation

    International Nuclear Information System (INIS)

    Castaneda, M. A.; Cruz, M. A.; Cardenas, J. B.; Vargas, A.; Cruz, H. J.; Mercado, J. J.

    2010-10-01

    Annulus pressurization, jet impingement, pipe whip restraint and jet thrust are phenomena related to postulated pipe ruptures. A postulated pipe rupture at the weld between recirculation, or feedwater piping and a reactor nozzle safe end, will lead to a high flow rate of flashing water/steam mixture into the annulus between the reactor pressure vessel and the biological shield wall. The total effect of the vessel and pipe inventory blowdown from the break being postulated must be accounted for in the evaluation. A recirculation line break will give rise to an angular dependent short term pressure differential around the vessel, followed by a longer term pressure buildup in the annulus. A recirculation line postulated rupture may not produce worst case conditions and reference to time intervals for only the recirculation break should be treated superficially. A postulated rupture of the feedwater piping may produce the extreme case for determining: 1) the shield wall and reactor vessel to pedestal interactions, 2) loading on the reactor vessel internals, or 3) responses for the balance of piping attached to the vessel. Recently it was identified a potential issue regarding the criteria used to determine which cases were evaluated for Annulus Pressurization (A P) loads for new loads plants. The original A P loads methodology in the late 1970 and early 1980 years separated the mass/energy release calculation from the structural response calculation based on the implicit assumption that the maximum overall mass/energy release will result in maximizing the structural response and corresponding stresses on the reactor pressure vessel, internals, and containment structures. This process did not consider the dynamic response in the primary and secondary safety related structures, components and equipment. Consequently, the A P loads used as input for design adequacy evaluations of Nuclear Steam Supply System safety related components for new loads plants might have

  19. Radiation and viscous dissipation effect on square porous annulus

    Energy Technology Data Exchange (ETDEWEB)

    Badruddin, Irfan Anjum [Dept. of Mechanical Engineering, University of Malaya, Kuala Lumpur, 50603 (Malaysia); Quadir, G. A. [School of Mechatronic Engineering, University Malaysia Perlis, Pauh Putra, 02600 Arau, Perlis (Malaysia)

    2016-06-08

    The present study is carried out to investigate the effect of radiation and viscous dissipation in a square porous annulus subjected to outside hot T{sub h} and inside cold T{sub c} temperature. The square annulus has a hollow section of dimension D×D at the interior of annulus. The flow is assumed to obey Darcy law. The governing equations are non-dimensionalised and solved with the help of finite element method. Results are discussed with respect to viscous dissipation parameter, radiation parameter and size of the hollow section of annulus.

  20. Spacer grid corner gusset

    International Nuclear Information System (INIS)

    Larson, J.G.

    1984-01-01

    There is provided a spacer grid for a bundle of longitudinally extending rods in spaced generally parallel relationship comprising spacing means for holding the rods in spaced generally parallel relationship; the spacing means includes at least one exterior grid strip circumscribing the bundle of rods along the periphery thereof; with at least one exterior grid strip having a first edge defining the boundary of the strip in one longitudinal direction and a second edge defining the boundary of the strip in the other longitudinal direction; with at least one exterior grid strip having at least one band formed therein parallel to the longitudinal direction; a plurality of corner gussets truncating each of a plurality of corners formed by at least one band and the first edge and the second edge

  1. COMPARISON OF PREOPERATIVE NONINVASIVE AND INTRAOPERATIVE MEASUREMENTS OF AORTIC ANNULUS

    Directory of Open Access Journals (Sweden)

    Manish Hinduja

    2016-10-01

    Full Text Available BACKGROUND Precise preoperative assessment of aortic annulus diameter is essential for sizing of aortic valve especially in patients planned for transcatheter aortic valve replacement. Computed Tomographic (CT and echocardiographic measurements of the aortic annulus vary because of elliptical shape of aortic annulus. This study was undertaken to compare the measurement of aortic annulus intraoperatively with preoperative noninvasive methods in patients undergoing aortic valve replacement. MATERIALS AND METHODS Aortic annulus diameter was measured with cardiac CT and Transesophageal Echocardiography (TEE prior to open aortic valve replacement in 30 patients with aortic valve stenosis. In CT, aortic annulus dimensions were measured in coronal plane, sagittal oblique plane and by planimetry. Both 2-dimensional and 3-dimensional TEE were used. These were compared with intraoperative measurements done by valve sizers and Hegar dilators. Pearson analysis was applied to test for degree of correlation. RESULTS CT in coronal and sagittal oblique plane tends to overestimate the diameter of aortic annulus when compared with intraoperative measurements (coefficient of relation, r = 0.798 and 0.749, respectively. CT measurements in single oblique plane showed a weaker correlation with intraoperative measurements than 3D TEE and 2D TEE (r = 0.917 and 0.898, respectively. However, CT measurements by planimetry method were most correlating with the intraoperative measurements (r = 0.951. CONCLUSION Noninvasive investigations with 3-dimensional views (CT-based measurement employing calculated average diameter assessment by planimetry and 3-dimensional TEE showed better correlation with intraoperative measurement of aortic annulus. CT-based aortic annulus measurement by planimetry seems to provide adequate dimensions most similar to operative measurements.

  2. Flow of Giesekus viscoelastic fluid in a concentric annulus with inner cylinder rotation

    International Nuclear Information System (INIS)

    Ravanchi, Maryam Takht; Mirzazadeh, Mahmoud; Rashidi, Fariborz

    2007-01-01

    An approximate analytical solution is derived for the steady state, purely tangential flow of a viscoelastic fluid obeying the Giesekus constitutive equation in a concentric annulus with inner cylinder rotation. An approximation is used for the estimation of radial normal stress. The effect of Weissenberg number (We), radius ratio (κ) and mobility factor (α) on velocity distribution and fRe are investigated. The results show that the velocity gradient near the inner cylinder increases as the fluid elasticity increases. The results also show that fRe decreases with increasing fluid elasticity

  3. Spacer grid for fuel elements

    International Nuclear Information System (INIS)

    Hensolt, T.; Huenner, M.; Rau, P.; Veca, A.

    1978-01-01

    The spacer grid for fuel elements of a gas-cooled fast breeder reactor (but also for PWRs and BWRs) consists of a lattice field with dodecagonal meshes. These meshes are formed by three each adjacent hexagons grouped arround a central axis. The pairs of legs extending into the dodecagon and being staggered by 120 0 are designed as knubs with inclined abutting surfaces for the fuel rods. By this means there is formed a three-point bearing for centering the fuel rods. The spacer grid mentioned above is rough-worked from a single disc- resp. plate-shaped body (unfinished piece). (DG) [de

  4. Spacer grid for fuel elements

    International Nuclear Information System (INIS)

    Hensolt, T.; Huenner, M.; Rau, P.; Veca, A.

    1980-01-01

    The spacer grid for fuel elements of a gas-cooled fast breeder reactor (but also for PWRs and BWRs) consists of a lattice field with dodecagonal meshes. These meshes are formed by three each adjacent hexagons grouped arround a central axis. The pairs of legs extending into the dodecagon and being staggered by 120 are designed as knubs with inclined abutting surfaces for the fuel rods. By this means there is formed a three-point bearing for centering the fuel rods. The spacer grid mentioned above is rough-worked from a single disc- resp. plate-shaped body (unfinished piece). (orig.)

  5. Characteristics of steam jet impingement on annulus

    International Nuclear Information System (INIS)

    Yoon, Sang H.; Kim, Won J.; Suh, Kune Y.; Song, Chul H.

    2004-01-01

    The steam jet impingement occurs when the steam through the cold leg from the steam generator strikes the inner reactor barrel during the reflood phase of a loss-of-coolant accident (LOCA), which is a characteristic behavior for the APR1400 (Advanced Power Reactor 1400 MWe). In the cold leg break LOCA, the steam and water flows in the downcomer are truly multidimensional. The azimuthal velocity distribution of the steam flow has an important bearing on the thermal hydraulic phenomena such as the emergency coolant water direct bypass, sweepout, steam condensation, and so forth. The investigation of jet flow is required to determine the steam path and momentum reduction rate after the impingement. For the observation of the steam behavior near the break, the computational fluid dynamic (CFD) analysis has been carried out using CFX5.6. The flow visualization and analysis demonstrate the velocity profiles of the steam flow in the annulus region for the same boundary conditions. Pursuant to the CFD results, the micro-Pitot tubes were positioned at varying angles, and corrected for their sensitivity. The experiments were carried out to directly measure the pressure differential and to visualize the flow utilizing a smoke injection method. Results from this study are slated to be applied to MARS, which is a thermal hydraulic system code for the best-estimate analysis. The current one- or two-dimensional analysis in MARS was known to distort the local flow behavior. To enhance prediction capability of MARS, it is necessary to inspect the steam path in the break flow and mechanically simulate the momentum variation. The present experimental and analytical results can locally be applied to developing the engineering models of specific and essential phenomena. (author)

  6. TERRESTRIAL PLANET FORMATION FROM AN ANNULUS

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, Kevin J.; Levison, Harold F., E-mail: kwalsh@boulder.swri.edu [Southwest Research Institute, 1050 Walnut St. Suite 300, Boulder, CO 80302 (United States)

    2016-09-01

    It has been shown that some aspects of the terrestrial planets can be explained, particularly the Earth/Mars mass ratio, when they form from a truncated disk with an outer edge near 1.0 au. This has been previously modeled starting from an intermediate stage of growth utilizing pre-formed planetary embryos. We present simulations that were designed to test this idea by following the growth process from km-sized objects located between 0.7 and 1.0 au up to terrestrial planets. The simulations explore initial conditions where the solids in the disk are planetesimals with radii initially between 3 and 300 km, alternately including effects from a dissipating gaseous solar nebula and collisional fragmentation. We use a new Lagrangian code known as LIPAD, which is a particle-based code that models the fragmentation, accretion, and dynamical evolution of a large number of planetesimals, and can model the entire growth process from km-sizes up to planets. A suite of large (∼ Mars mass) planetary embryos is complete in only ∼1 Myr, containing most of the system mass. A quiescent period then persists for 10–20 Myr characterized by slow diffusion of the orbits and continued accretion of the remaining planetesimals. This is interrupted by an instability that leads to embryos crossing orbits and embryo–embryo impacts that eventually produce the final set of planets. While this evolution is different than that found in other works exploring an annulus, the final planetary systems are similar, with roughly the correct number of planets and good Mars-analogs.

  7. Tricuspid annulus: A spatial and temporal analysis

    Directory of Open Access Journals (Sweden)

    Ziyad O Knio

    2016-01-01

    Full Text Available Background: Traditional two-dimensional (2D echocardiographic evaluation of tricuspid annulus (TA dilation is based on single-frame measurements of the septolateral (S-L dimension. This may not represent either the axis or the extent of dynamism through the entire cardiac cycle. In this study, we used real-time 3D transesophageal echocardiography (TEE to analyze geometric changes in multiple axes of the TA throughout the cardiac cycle in patients without right ventricular abnormalities. Materials and Methods: R-wave-gated 3D TEE images of the TA were acquired in 39 patients undergoing cardiovascular surgery. The patients with abnormal right ventricular/tricuspid structure or function were excluded from the study. For each patient, eight points along the TA were traced in the 3D dataset and used to reconstruct the TA at four stages of the cardiac cycle (end- and mid-systole, end- and mid-diastole. Statistical analyses were applied to determine whether TA area, perimeter, axes, and planarity changed significantly over each stage of the cardiac cycle. Results: TA area (P = 0.012 and perimeter (P = 0.024 both changed significantly over the cardiac cycle. Of all the axes, only the posterolateral-anteroseptal demonstrated significant dynamism (P < 0.001. There was also a significant displacement in the vertical axis between the points and the regression plane in end-systole (P < 0.001, mid-diastole (P = 0.014, and mid-systole (P < 0.001. Conclusions: The TA demonstrates selective dynamism over the cardiac cycle, and its axis of maximal dynamism is different from the axis (S-L that is routinely measured with 2D TEE.

  8. Thermal convection in dielectric liquids in a cylindrical annulus

    Science.gov (United States)

    Mutabazi, Innocent; Kang, Changwoo; Meyer, Antoine; Meier, Martin; Egbers, Christoph

    2017-11-01

    Thermal convection is investigated in a dielectric liquid of thermal expansion coefficient α, kinematic viscosity ν, thermal diffusivity κ and electric permittivity ɛ in a cylindrical annulus of inner radius a and outer radius bwith a radial temperature gradient and a high-frequency electric tension. The coupling between the electric field and the gradient of the permittivity yields the dielectrophoretic force. The control parameters are η = a/b, Pr = ν / κ, the classic Rayleigh number Ra = αΔ T gd3 / νκ , and the electric Rayleigh number L = αΔ T ged3 / νκ The electric gravity ge is the gradient of the electric energy in the condenser. Linear stability analysis shows that for infinite annulus, depending on values of η, Ra and L, critical modes are either hydrodynamic or thermal modes, helical electric modes or columnar vortices. Experiments in an annulus of aspect ratio Γ = 19.6 during parabolic flight campaigns indicate the existence of columns. Columnar vortices result from the competition between Archimedean buoyancy and dielectrophoretic force. Direct numerical simulations in the annulus of Γ = 20 show that the columnar vortices occupy the central part of the annulus, while near the end-zones the flow is laminar and dominated by an azimuthal vorticity. This work was supported by CNRS (LIA ISTROF), CNES and DLR.

  9. Flow of viscoplastic fluids in a rotating concentric annulus

    DEFF Research Database (Denmark)

    Hassager, Ole; Bittleston, Simon H.

    1992-01-01

    A difficulty in any flow calculation with viscoplastic fluids such as Bingham fluids is the determination of possible plug zones in which no deformation occurs. This paper investigates the flow in a concentric annulus when there is both an axial and tangential flow, the tangent flow arising from...... rotation of the inner cylinder of the annulus. The flow is analyzed by considering flow in a slot, for which an analytical solution is given, and by solving the full problem numerically. It is shown that when the boundary is set in motion an applied pressure gradient will always cause flow. If the applied...... pressure gradient is small compared to the yield stress of the fluid then the full solution predicts the existence of plugs attached to the outer wall of the annulus. The slot approximation fails to predict this feature. For larger pressure gradients the two solutions are in good agreement. The analytical...

  10. Nucleate boiling pressure drop in an annulus: Book 7

    Energy Technology Data Exchange (ETDEWEB)

    1992-11-01

    The application of the work described in this report is the production reactors at the Savannah River Site, and the context is nuclear reactor safety. The Loss of Coolant Accident (LOCA) scenario considered involves a double-ended break of a primary coolant pipe in the reactor. During a LOCA, the flow through portions of the reactor may reverse direction or be greatly reduced, depending upon the location of the break. The reduced flow rate of coolant (D{sub 2}O) through the fuel assembly channels of the reactor -- downflow in this situation -- can lead to boiling and to the potential for flow instabilities which may cause some of the fuel assembly channels to overheat and melt. That situation is to be avoided. The experimental approach is to provide a test annulus which simulates geometry, materials, and flow conditions in a Mark-22 fuel assembly (Coolant Channel 3) to the extent possible. The annulus has a full-scale geometry, and in fat uses SRL dummy hardware for the inner annulus wall in the ribbed geometry. The materials aluminum. The annulus is uniformly heated in the axial direction, but the circumferential heat flux can be varied to provide ``power tilt`` or asymmetric heating of the inner and outer annulus walls. The test facility uses H{sub 2}O rather than D{sub 2}O, but it includes the effects of dissolved helium gas present in the reactor. The key analysis approaches are: To compare the minima in the measured demand curves with analytical criteria, in particular the Saha-Zuber (1974) model; and to compare the pressure and temperature as a function of length in the annulus with an integral model for flow boiling in a heated channel. This document consists solely of tables of temperature measurements; minima, maxima, averages and standard deviations being measured.

  11. Nucleate boiling pressure drop in an annulus: Book 4

    Energy Technology Data Exchange (ETDEWEB)

    Block, J.A.; Crowley, C.; Dolan, F.X.; Sam, R.G.; Stoedefalke, B.H.

    1992-11-01

    The application of the work described in this report is the production reactors at the Savannah River Site, and the context is nuclear reactor safety. The Loss of Coolant Accident (LOCA) scenario considered involves a double-ended break of a primary coolant pipe in the reactor. During a LOCA, the flow through portions of the reactor may reverse direction or be greatly reduced, depending upon the location of the break. The reduced flow rate of coolant (D{sub 2}O) through the fuel assembly channels of the reactor -- downflow in this situation -- can lead to boiling and to the potential for flow instabilities which may cause some of the fuel assembly channels to overheat and melt. That situation is to be avoided. The experimental approach is to provide a test annulus which simulates geometry, materials, and flow conditions in a Mark-22 fuel assembly (Coolant Channel 3) to the extent possible. The annulus has a full-scale geometry, and in fat uses SRL dummy hardware for the inner annulus wall in the ribbed geometry. The materials aluminum. The annulus is uniformly heated in the axial direction, but the circumferential heat flux can be varied to provide ``power tilt`` or asymmetric heating of the inner and outer annulus walls. The test facility uses H{sub 2}O rather than D{sub 2}O, but it includes the effects of dissolved helium gas present in the reactor. The key analysis approaches are: To compare the minima in the measured demand curves with analytical criteria, in particular the Saha-Zuber (1974) model; and to compare the pressure and temperature as a function of length in the annulus with an integral model for flow boiling in a heated channel. This document consists of data plots and summary files of temperature measurements.

  12. Nucleate boiling pressure drop in an annulus: Book 6

    International Nuclear Information System (INIS)

    1992-11-01

    The application of the work described in this report is the production reactors at the Savannah River Site, and the context is nuclear reactor safety. The Loss of Coolant Accident (LOCA) scenario considered involves a double-ended break of a primary coolant pipe in the reactor. During a LOCA, the flow through portions of the reactor may reverse direction or be greatly reduced, depending upon the location of the break. The reduced flow rate of coolant (D 2 O) through the fuel assembly channels of the reactor -- downflow in this situation -- can lead to boiling and to the potential for flow instabilities which may cause some of the fuel assembly channels to overheat and melt. That situation is to be avoided. The experimental approach is to provide a test annulus which simulates geometry, materials, and flow conditions in a Mark-22 fuel assembly (Coolant Channel 3) to the extent possible. The annulus has a full-scale geometry, and in fat uses SRL dummy hardware for the inner annulus wall in the ribbed geometry. The materials aluminum. The annulus is uniformly heated in the axial direction, but the circumferential heat flux can be varied to provide ''power tilt'' or asymmetric heating of the inner and outer annulus walls. The test facility uses H 2 O rather than D 2 O, but it includes the effects of dissolved helium gas present in the reactor. The key analysis approaches are: To compare the minima in the measured demand curves with analytical criteria, in particular the Saha-Zuber (1974) model; and to compare the pressure and temperature as a function of length in the annulus with an integral model for flow boiling in a heated channel. This document consists of a summary of temperature measurements to include recorded minima, maxima, averages and standard deviations

  13. Nucleate boiling pressure drop in an annulus: Book 6

    Energy Technology Data Exchange (ETDEWEB)

    1992-11-01

    The application of the work described in this report is the production reactors at the Savannah River Site, and the context is nuclear reactor safety. The Loss of Coolant Accident (LOCA) scenario considered involves a double-ended break of a primary coolant pipe in the reactor. During a LOCA, the flow through portions of the reactor may reverse direction or be greatly reduced, depending upon the location of the break. The reduced flow rate of coolant (D{sub 2}O) through the fuel assembly channels of the reactor -- downflow in this situation -- can lead to boiling and to the potential for flow instabilities which may cause some of the fuel assembly channels to overheat and melt. That situation is to be avoided. The experimental approach is to provide a test annulus which simulates geometry, materials, and flow conditions in a Mark-22 fuel assembly (Coolant Channel 3) to the extent possible. The annulus has a full-scale geometry, and in fat uses SRL dummy hardware for the inner annulus wall in the ribbed geometry. The materials aluminum. The annulus is uniformly heated in the axial direction, but the circumferential heat flux can be varied to provide ``power tilt`` or asymmetric heating of the inner and outer annulus walls. The test facility uses H{sub 2}O rather than D{sub 2}O, but it includes the effects of dissolved helium gas present in the reactor. The key analysis approaches are: To compare the minima in the measured demand curves with analytical criteria, in particular the Saha-Zuber (1974) model; and to compare the pressure and temperature as a function of length in the annulus with an integral model for flow boiling in a heated channel. This document consists of a summary of temperature measurements to include recorded minima, maxima, averages and standard deviations.

  14. Nucleate boiling pressure drop in an annulus: Book 3

    International Nuclear Information System (INIS)

    Block, J.A.; Crowley, C.; Dolan, F.X.; Sam, R.G.; Stoedefalke, B.H.

    1992-11-01

    The application of the work described in this report is the production reactors at the Savannah River Site, and the context is nuclear reactor safety. The Loss of Coolant Accident (LOCA) scenario considered involves a double-ended break of a primary coolant pipe in the reactor. During a LOCA, the flow through portions of the reactor may reverse direction or be greatly reduced, depending upon the location of the break. The reduced flow rate of coolant (D 2 O) through the fuel assembly channels of the reactor -- downflow in this situation -- can lead to boiling and to the potential for flow instabilities which may cause some of the fuel assembly channels to overheat and melt. That situation is to be avoided. The experimental approach is to provide a test annulus which simulates geometry, materials, and flow conditions in a Mark-22 fuel assembly (Coolant Channel 3) to the extent possible. The annulus has a full-scale geometry, and in fat uses SRL dummy hardware for the inner annulus wall in the ribbed geometry. The materials aluminum. The annulus is uniformly heated in the axial direction, but the circumferential heat flux can be varied to provide ''power tilt'' or asymmetric heating of the inner and outer annulus walls. The test facility uses H 2 O rather than D 2 O, but it includes the effects of dissolved helium gas present in the reactor. The key analysis approaches are: To compare the minima in the measured demand curves with analytical criteria, in particular the Saha-Zuber (1974) model; and to compare the pressure and temperature as a function of length in the annulus with an integral model for flow boiling in a heated channel. This document consists of data plots and summary files of temperature measurements

  15. Nucleate boiling pressure drop in an annulus: Book 3

    Energy Technology Data Exchange (ETDEWEB)

    Block, J.A.; Crowley, C.; Dolan, F.X.; Sam, R.G.; Stoedefalke, B.H.

    1992-11-01

    The application of the work described in this report is the production reactors at the Savannah River Site, and the context is nuclear reactor safety. The Loss of Coolant Accident (LOCA) scenario considered involves a double-ended break of a primary coolant pipe in the reactor. During a LOCA, the flow through portions of the reactor may reverse direction or be greatly reduced, depending upon the location of the break. The reduced flow rate of coolant (D{sub 2}O) through the fuel assembly channels of the reactor -- downflow in this situation -- can lead to boiling and to the potential for flow instabilities which may cause some of the fuel assembly channels to overheat and melt. That situation is to be avoided. The experimental approach is to provide a test annulus which simulates geometry, materials, and flow conditions in a Mark-22 fuel assembly (Coolant Channel 3) to the extent possible. The annulus has a full-scale geometry, and in fat uses SRL dummy hardware for the inner annulus wall in the ribbed geometry. The materials aluminum. The annulus is uniformly heated in the axial direction, but the circumferential heat flux can be varied to provide ``power tilt`` or asymmetric heating of the inner and outer annulus walls. The test facility uses H{sub 2}O rather than D{sub 2}O, but it includes the effects of dissolved helium gas present in the reactor. The key analysis approaches are: To compare the minima in the measured demand curves with analytical criteria, in particular the Saha-Zuber (1974) model; and to compare the pressure and temperature as a function of length in the annulus with an integral model for flow boiling in a heated channel. This document consists of data plots and summary files of temperature measurements.

  16. Flow of viscoplastic fluids in a rotating concentric annulus

    DEFF Research Database (Denmark)

    Hassager, Ole; Bittleston, Simon H.

    1992-01-01

    A difficulty in any flow calculation with viscoplastic fluids such as Bingham fluids is the determination of possible plug zones in which no deformation occurs. This paper investigates the flow in a concentric annulus when there is both an axial and tangential flow, the tangent flow arising from...... pressure gradient is small compared to the yield stress of the fluid then the full solution predicts the existence of plugs attached to the outer wall of the annulus. The slot approximation fails to predict this feature. For larger pressure gradients the two solutions are in good agreement. The analytical...

  17. Radius ratio effects on natural heat transfer in concentric annulus

    DEFF Research Database (Denmark)

    Alipour, M.; Hosseini, R.; Kolaei, Alireza Rezania

    2013-01-01

    This paper studies natural convection heat transfer in vertical and electrically heated annulus. The metallic cylinders mounted concentrically in a parallel tube. Measurements are carried out for four input electric powers and three radius ratios with an apparatus immersed in stagnant air....... This experimental work develops correlations of the average Nusselt number dependency on the Rayleigh number in the annulus, where this dependency promotes as the radius ratio increases from 0.1 to 0.2. Moreover, a correlation is proposed to determine the average Nusselt number based on the variation of the radius...

  18. Reproducibility of aortic annulus measurements by computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Schuhbaeck, Annika; Achenbach, Stephan [University of Erlangen, Department of Cardiology, Erlangen (Germany); University of Giessen, Department of Cardiology, Giessen (Germany); Pflederer, Tobias; Marwan, Mohamed; Schmid, Jasmin; Arnold, Martin [University of Erlangen, Department of Cardiology, Erlangen (Germany); Nef, Holger; Rixe, Johannes; Hecker, Franziska [University of Giessen, Department of Cardiology, Giessen (Germany); Schneider, Christian [University of Giessen, Department of Radiology, Giessen (Germany); Lell, Michael; Uder, Michael [University of Erlangen, Department of Radiology, Erlangen (Germany)

    2014-08-15

    To evaluate a systematic approach for measurement of aortic annulus dimensions by cardiac computed tomography. CT data sets of 64 patients were evaluated. An oblique cross-section aligned with the aortic root was created by systematically identifying the caudal insertion points of the three aortic cusps and sequentially aligning them in a double oblique plane. Aortic annulus dimensions, distances of coronary ostia and a suitable fluoroscopic projection angle were independently determined by two observers. Interobserver intraclass correlation coefficients (ICC) for aortic annulus diameters were excellent (ICC 0.89-0.93). Agreement for prosthesis size selection was excellent (k = 0.86 for mean, k = 0.84 for area-derived and k = 0.91 for circumference-derived diameter). Mean distances of the left/right coronary ostium were 13.4 ± 2.4/14.4 ± 2.8 mm for observer 1 and 13.2 ± 2.7/13.5 ± 3.2 mm for observer 2 (p = 0.30 and p = 0.0001, respectively; ICC 0.76/0.77 for left/right coronary artery). A difference of less than 10 for fluoroscopic projection angle was achieved in 84.3 % of patients. A systematic approach to generate a double oblique imaging plane exactly aligned with the aortic annulus demonstrates high interobserver and intraobserver agreements for derived measurements which are not influenced by aortic root calcification. (orig.)

  19. ANALYSIS OF FLOW IN A CONCENTRIC ANNULUS USING FINITE ...

    African Journals Online (AJOL)

    This work presents the computational modelling of the velocity distribution of an incompressible fluid flowing in a cylindrical annulus pipe, using the finite element method. The result shows that the velocity distribution increases from the boundaries until midway between the boundaries where it was maximum. Also, the ...

  20. Two pion correlation from SPACER

    International Nuclear Information System (INIS)

    Csoergoe, T.; Zimanyi, J.; Pratt, S.

    1989-12-01

    The correlation function for neutral and negative pions produced in ultrarelativistic heavy ion collisions was calculated without free parameters based on a space-time version of the LUND model, called SPACER: Simulation of Phase space distribution of Atomic nuclear Collisions in Energetic Reactions. This method includes the effect of Bose correlations for the emitted pion pair. Effects arising from correlations between space-time and momentum space distributions are investigated. The results are compared to the data of two different experiments. The role and interpretation of the chaocity parameter are discussed. (D.G.) 14 refs.; 4 figs

  1. Spacers for fuel rod clusters

    International Nuclear Information System (INIS)

    Jabsen, F.S.

    1978-01-01

    The proposition deals with the fixing of nuclear fuel element rods in a grid which consists of a number of crossed Zy-plates which form cells. The rectangular cells have projections which serve as spacers for the fuel rods. According to the invention there are additional butt straps which can be moved in such a way that insertion and extraction of the fuel rods can be done without obstruction and they can be spring-loaded hold in their final position. (UWI) [de

  2. Removal of 14C from nitrogen annulus gas

    International Nuclear Information System (INIS)

    Cheh, C.H.

    1985-01-01

    A dry, ambient temperature process using Ca(OH) 2 as the sorbent to remove 14 CO 2 from moderator cover gas was further developed to remove 14 C from the extremely dry nitrogen annulus gas. Thermal gravimetric analysis was carried out to study the thermal stability of Ca(OH) 2 and the CO 2 -Ca(OH) 2 reaction at elevated temperatures under extremely low humidity conditions. Results shows that to achieve high utilization and avoid decomposition of Ca(OH) 2 , humidification of the annulus gas was necessary at high or low temperatures. Results of the bench scale (1-10 L/min) oxidizer study showed that, with 0.5% Pd or alumina as the catalyst, it was possible to achieve complete oxidation of CO and over 80% oxidation of CH 4 with 1% hydrogen in the nitrogen. The gas superficial velocity should be less than or equal to30 cm/s and the residence time greater than or equal to0.5 s. A pilot scale (up to 160 L/min) system including a catalytic oxidizer, a humidifier/demister, a Ca(OH) 2 reactor, a condenser/demister and regenerable molecular sieve dryers, was assembled and tested with simulated nitrogen annulus gas. Results showed that complete oxidation of the CO and 60-100% oxidation of the CH 4 with 0.5% H 2 in the simulated gas were achieved in the pilot plant. The CO 2 concentration was reduced from 30-60 μL/L at the inlet of the Ca(OH) 2 reactor to 1 μL/L or less at the outlet. After modifications of the dryer to overcome the problems encountered, the simulated annulus gas was dried to 0 C dew point before recirculation. Equipment specifications and operating conditions of a 14 C removal system for nitrogen annulus gas are summarized

  3. Development of a High Performance Spacer Grid

    Energy Technology Data Exchange (ETDEWEB)

    Song, Kee Nam; Song, K. N.; Yoon, K. H. (and others)

    2007-03-15

    A spacer grid in a LWR fuel assembly is a key structural component to support fuel rods and to enhance the heat transfer from the fuel rod to the coolant. In this research, the main research items are the development of inherent and high performance spacer grid shapes, the establishment of mechanical/structural analysis and test technology, and the set-up of basic test facilities for the spacer grid. The main research areas and results are as follows. 1. 18 different spacer grid candidates have been invented and applied for domestic and US patents. Among the candidates 16 are chosen from the patent. 2. Two kinds of spacer grids are finally selected for the advanced LWR fuel after detailed performance tests on the candidates and commercial spacer grids from a mechanical/structural point of view. According to the test results the features of the selected spacer grids are better than those of the commercial spacer grids. 3. Four kinds of basic test facilities are set up and the relevant test technologies are established. 4. Mechanical/structural analysis models and technology for spacer grid performance are developed and the analysis results are compared with the test results to enhance the reliability of the models.

  4. Development of a High Performance Spacer Grid

    International Nuclear Information System (INIS)

    Song, Kee Nam; Song, K. N.; Yoon, K. H.

    2007-03-01

    A spacer grid in a LWR fuel assembly is a key structural component to support fuel rods and to enhance the heat transfer from the fuel rod to the coolant. In this research, the main research items are the development of inherent and high performance spacer grid shapes, the establishment of mechanical/structural analysis and test technology, and the set-up of basic test facilities for the spacer grid. The main research areas and results are as follows. 1. 18 different spacer grid candidates have been invented and applied for domestic and US patents. Among the candidates 16 are chosen from the patent. 2. Two kinds of spacer grids are finally selected for the advanced LWR fuel after detailed performance tests on the candidates and commercial spacer grids from a mechanical/structural point of view. According to the test results the features of the selected spacer grids are better than those of the commercial spacer grids. 3. Four kinds of basic test facilities are set up and the relevant test technologies are established. 4. Mechanical/structural analysis models and technology for spacer grid performance are developed and the analysis results are compared with the test results to enhance the reliability of the models

  5. Mobilities

    DEFF Research Database (Denmark)

    and environmental degradation. The spaces and territories marked by mobilities as well as the sites marked by the bypassing of such are explored. Moreover, the architectural and technological dimensions to infrastructures and sites of mobilities will be included as well as the issues of power, social exclusion...... for all students and scholars with an interest in the ‘mobilities turn’ and its contributions to a deeper understanding of the contemporary and mobile world. The entries chosen all are amongst the most creative, thought provoking, and thoughtful of this diverse field of analysis and thought. The selection...

  6. Spacer for supporting fuel element boxes

    International Nuclear Information System (INIS)

    Wild, E.

    1979-01-01

    A spacer plate unit arranged externally on each side and at a predetermined level of a polygonal fuel element box for mutually supporting, with respect to one another, a plurality of the fuel element boxes forming a fuel element bundle, is formed of a first and a second spacer plate part each having the same length and the same width and being constituted of unlike first and second materials, respectively. The first and second spacer plate parts of the several spacer plate units situated at the predetermined level are arranged in an alternating continuous series when viewed in the peripheral direction of the fuel element box, so that any two spacer plate units belonging to face-to-face oriented sides of two adjoining fuel element boxes in the fuel element bundle define interfaces of unlike materials

  7. Nematic Equilibria on a Two-Dimensional Annulus

    KAUST Repository

    Lewis, A. H.

    2017-01-16

    We study planar nematic equilibria on a two-dimensional annulus with strong and weak tangent anchoring, in the Oseen–Frank theoretical framework. We analyze a radially invariant defect-free state and compute analytic stability criteria for this state in terms of the elastic anisotropy, annular aspect ratio, and anchoring strength. In the strong anchoring case, we define and characterize a new spiral-like equilibrium which emerges as the defect-free state loses stability. In the weak anchoring case, we compute stability diagrams that quantify the response of the defect-free state to radial and azimuthal perturbations. We study sector equilibria on sectors of an annulus, including the effects of weak anchoring and elastic anisotropy, giving novel insights into the correlation between preferred numbers of boundary defects and the geometry. We numerically demonstrate that these sector configurations can approximate experimentally observed equilibria with boundary defects.

  8. Simple annulus power balance in EBT-I

    International Nuclear Information System (INIS)

    Borowski, S.K.; Uckan, N.A.; Jaeger, E.F.; Kammash, T.

    1979-09-01

    An essential feature of the ELMO Bumpy Torus (EBT) concept is the presence of a relativistic electron annulus in each of the toroidal mirror sectors. These high beta annuli are formed and sustained by microwave heating and are of sufficient density and temperature that diamagnetic currents produce the necessary minimum in the magnetic field required for MHD stability of the toroidal core plasma. Because electron rings play an important role in confinement characteristics and performance of EBT, the trade-off between the quality of the confinement afforded by the rings and the power required to sustain the rings represents an important problem in a fusion reactor. Theoretical estimates of the microwave power required to sustain the annulus are found to be within a factor of 2 of the experimentally determined value. Scaling projections that are shown for both EBT-I and EBT-S enable one to examine the sensitivity of the annulus electron temperature as a function of core plasma density for various microwave power levels. The results are found to be sensitive to the details of the hot electron distribution function as well as geometric and scaling parameters. Improvements to the model are under way in order to increase its capability and accuracy in assessing the overall power balance

  9. Mobilities

    DEFF Research Database (Denmark)

    will cover diverse topics such as theories, concepts, methods, and approaches as well as it will explore various modes of mobilities and the relationship to everyday life practices. The selection also covers the ‘politics of mobilities’ from local urban planning schemes to geopolitical issues of refugees...

  10. Application of spacer fabrics in composite production

    OpenAIRE

    Mecit, Diren; , Arzu Marmaralı

    2012-01-01

    Developments in the field of textile reinforced composites have been increasing in the last several years. In the first developed composite materials, fibers were used as reinforcement element. Textile materials such as staple fibers, bands, filament yarns, cables and two dimensional textiles are widely used as reinforcement elements in composite materials. Spacer fabrics consist of two outer surfaces and a connection layer between those outer surfaces. Spacer fabrics can be classified in the...

  11. Application of spacer fabrics in composite production

    OpenAIRE

    Mecit, Diren; -, Arzu Marmaralı

    2014-01-01

    Developments in the field of textile reinforced composites have been increasing in the last several years. In the first developed composite materials, fibers were used as reinforcement element. Textile materials such as staple fibers, bands, filament yarns, cables and two dimensional textiles are widely used as reinforcement elements in composite materials. Spacer fabrics consist of two outer surfaces and a connection layer between those outer surfaces. Spacer fabrics can be classified in the...

  12. Numerical analysis of laminar forced convection in a spherical annulus

    International Nuclear Information System (INIS)

    Tuft, D.B.

    1980-01-01

    Calculations of steady laminar incompressible fluid-flow and heat transfer in a spherical annulus are presented. Steady pressures, temperatures, velocities, and heat transfer coefficients are calculated for an insulated outer sphere and a 0 0 C isothermal inner sphere with 50 0 C heated water flowing in the annulus. The inner sphere radius is 13.97 cm, the outer sphere radius is 16.83 cm and the radius ratio is 1.2. The transient axisymmetric equations of heat, mass, and momentum conservation are solved numerically in spherical coordinates. The transient solution is carried out in time until steady state is achieved. A variable mesh is used to improve resolution near the inner sphere where temperature and velocity gradients are steep. It is believed that this is the first fully two-dimensional analysis of forced flow in a spherical annulus. Local and bulk Nusselt numbers are presented for Reynolds numbers from 4.4 to 440. Computed bulk Nusselt numbers ranged from 2 to 50 and are compared to experimental results from the literature. Inlet flow jetting off the inner sphere and flow separation are predicted by the analysis. The location of wall jet separation was found to be a function of Reynolds number, indicating the location of separation depends upon the ratio of inertia to viscous forces. Wall jet separation has a pronounced effect on the distribution of local heat flux. The area between inlet and separation was found to be the most significant area for heat transfer. Radial distributions of azimuthal velocity and temperature are presented for various angles beginning at the inlet. Inner sphere pressure distribution is presented and the effect on flow separation is discussed

  13. Magnetorotational Instability in a Rotating Liquid Metal Annulus

    International Nuclear Information System (INIS)

    Hantao Ji; Jeremy Goodman; Akira Kageyama

    2001-01-01

    Although the magnetorotational instability (MRI) has been widely accepted as a powerful accretion mechanism in magnetized accretion disks, it has not been realized in the laboratory. The possibility of studying MRI in a rotating liquid-metal annulus (Couette flow) is explored by local and global stability analysis and magnetohydrodynamic (MHD) simulations. Stability diagrams are drawn in dimensionless parameters, and also in terms of the angular velocities at the inner and outer cylinders. It is shown that MRI can be triggered in a moderately rapidly rotating table-top apparatus, using easy-to-handle metals such as gallium. Practical issues of this proposed experiment are discussed

  14. Nucleate boiling pressure drop in an annulus: Book 5

    Energy Technology Data Exchange (ETDEWEB)

    1992-11-01

    The application of the work described in this report is the production reactors at the Savannah River Site, and the context is nuclear reactor safety. The Loss of Coolant Accident (LOCA) scenario considered involves a double-ended break of a primary coolant pipe in the reactor. During a LOCA, the flow through portions of the reactor may reverse direction or be greatly reduced, depending upon the location of the break. The reduced flow rate of coolant (D{sub 2}O) through the fuel assembly channels of the reactor -- downflow in this situation -- can lead to boiling and to the potential for flow instabilities which may cause some of the fuel assembly channels to overheat and melt. That situation is to be avoided. The experimental approach is to provide a test annulus which simulates geometry, materials, and flow conditions in a Mark-22 fuel assembly (Coolant Channel 3) to the extent possible. The key analysis approaches are: To compare the minima in the measured demand curves with analytical criteria, in particular the Saha-Zuber (1974) model; and to compare the pressure and temperature as a function of length in the annulus with an integral model for flow boiling in a heated channel. Nineteen test series and a total of 178 tests were performed. Testing addressed the effects of: Heat flux; pressure; helium gas; power tilt; ribs; asymmetric heat flux. This document consists solely of the plato file index from 11/87 to 11/90.

  15. Thermal convection in a co-rotating cylindrical annulus

    Science.gov (United States)

    Kang, Changwoo; Meyer, Antoine; Mutabazi, Innocent

    2017-11-01

    We investigate thermal convection in a fluid of thermal expansion coefficient α, kinematic viscosity ν, thermal diffusivity κ in a cylindrical annulus of inner radius a and outer radius bwith a solid body rotation of angular frequency Ω and an inward heating with a temperature difference ΔT. The control parameters are η = a/b, Pr = ν / κ and the Rayleigh number Ra = αΔ T gd3 / νκ where the centrifugal gravity gc =Ω2 (a +b)/2. We adopt the generalized Boussinesq approximation. Linear stability analysis shows that for infinite annulus, the threshold Rac decreases with η and tends to the value Rac = 1708 when η -> 1 and that critical modes are columnar vortices. Direct numerical simulations using periodic boundary conditions in the axial direction, show that the columnar vortices appear via a supercritical bifurcation. Higher modes of columnar vortices have been determined using the frequency spectra and the Nusselt number for Pr =1 and η = 0.5 : drifting vortices, vacillation modes and chaotic modes have been identified from Ra =1700 to Ra =107 The contribution of the centrifugal buoyancy to the variation of the kinetic energy in the flow is analysed. This work was supported by the project BIOENGINE (CPER-FEDER, Normandie) and CNES.

  16. Dufour and Soret Effects on Square Porous Annulus

    Directory of Open Access Journals (Sweden)

    N. Nik-Ghazali

    2014-04-01

    Full Text Available A study on heat and mass transfer behaviour on porous medium embedded in a square annulus is conducted. The inner surface wall is considered to have a cool temperature Tc while the outer surface is exposed to a hot temperature Th. Finite element method (FEM is used to solve the governing partial differential equations. The results present the influences of the Dufour and Soret effects on the heat and mass transfer of a square annulus. The effects of various physical parameters on the temperature and concentration profiles together with the local Nusselt and Sherwood numbers are presented graphically. It is found that when Dufour parameter is increased, Nusselt number increases. Dufour effect has more influences on velocity profile, while it has no significant effect on the concentration and can be deemed negligible. It is observed that the local Nusselt number is highest at the bottom wall for low values of Dufour parameter; however, the top wall Nusselt number is highest for higher values of Dufour parameter. Soret effect tends to make more significant contribution to the concentration profile than Dufour effect.

  17. Deployment Plan for Small Roving Annulus Inspection Vehicle

    International Nuclear Information System (INIS)

    Minichan, R.

    2002-01-01

    The Small Roving Annulus Inspection Vehicle (SRAIV) is a modified commercially available wall crawler designed to supplement the In-Service Inspection (ISI) of Savannah River Site (SRS) Waste tanks. The SRAIV provides an improved capability to achieve a more complete inspection of the tank walls than existing methods. The SRAIV will be deployed through annulus risers in the tank to gain access to tank walls requiring inspection. The SRAIV will be deployed using a manually operated deployment pole and will be coupled to the wall using permanent magnet wheels. Navigation will be performed from the remote console where pictorial views can be displayed from the on-board cameras. The unit will incorporate multiple UT transducers for traditional weld examination. In addition, a specially developed Tandem Synthetic Aperture Focusing Technique (TSAFT) UT scanning bridge can be attached to provide further investigation of the knuckle region while the vehicle remains on the vertical surface of the tank wall. In summary, the SRAIV will provide features that enhance and expand the capability of the SRS ISI program

  18. Mitral annulus caseous calcification mimicking cardiac mass in asymptomatic patient – multimodality imaging approach to incidental echocardiographic finding

    International Nuclear Information System (INIS)

    Możeńska, Olga; Sypuła, Sławomir; Celińska-Spoder, Małgorzata; Walecki, Jerzy; Kosior, Dariusz A.

    2014-01-01

    Caseous calcification of mitral annulus is rather rare echocardiographic finding with prevalence of 0.6% in pts. with proven mitral annular calcification and 0.06% to 0.07% in large series of subjects in all ages. Echocardiographic images of caseous calcification are often heterogenous due to calcium and lipid deposits, and the masses show hyperechogenic and hypoechogenic areas. However the appearance of caseous calcification can imitate that of abscess, tumors and cysts, surgical treatment may not be needed when there is no obstruction. 76-year old obese (BMI 32 kg/m 2 ), female patient with history of hypertension, stable coronary artery disease, diabetes type 2 and hyperlipidemia presented with no symptoms of mitral valve dysfunction and had no abnormalities on physical exam. Transesophageal echocardiography identified well-organized, composite, immobile lesion (22×15 mm) localized in the posterior part of the mitral annulus, with markedly calcified margins, and no significant impact on the valve function. In computed tomography (CT) lesion was described as calcified (24×22×17.5 mm), connected with posterior leaflet and posterior part of the mitral annulus, reducing posterior leaflet mobility. CT brought the suggestion of caseous mitral annular calcification. Coming to a conclusion, bearing in mind no mitral valve dysfunction at that time, patient was offered conservative treatment. Although caseous mitral annular calcification is typically an incidental finding, accurate recognition is needed to avoid mistaking the lesion for a tumor or abscess, which may result in unnecessary cardiac surgery. However this entity is diagnosed on cardiac MRI, multi-modality imaging, especially non-contrast CT, allows for the confident, prospective diagnosis

  19. Aortic Annulus Enlargement: Early and Long-Terms Results.

    Science.gov (United States)

    Dumani, Selman; Likaj, Ermal; Dibra, Laureta; Beca, Vera; Kuci, Saimir; Refatllari, Ali

    2017-03-15

    Patient-prosthesis mismatch (PPM) is a common occurrence in aortic valve surgery. Even the discussions about the impact of this phenomenon on the results of aortic valve surgery, the management of this problem remain one of the main topics in this kind of surgery. One of the ways of a solution is aortic annulus enlargement. The main topic of this study is to evaluate the early and longterm results of this technique in our country. During the period January 2010 -January 2015, 641 patients performed aortic valve surgery. In ten patients we performed aortic annulus enlargement according to Manouguian technique to avoid severe patient-prothesis mismatch. Operative mortality and perioperative complications (low cardiac output, pulmonary complications, etc..) were considered the indicators of the early results. Survival, clinical presentation according to NYHA, quality of life were the indicators to evaluate long-term results. Preoperative and postoperative echocardiographic data were also used to evaluate our results. We collected the data from hospital registrations and periodical clinical visit and echographic examination after hospital discharge. In our group, 6 of 10 patients were diagnosed with stenotic aortic valve, two patients had aortic valve regurgitation and two mixed valve pathology. Four patients had concomitant cardiac surgery procedure, mitral or CABG. In all cases, aortic valve pathology was the primary diagnose. In the preoperative echocardiographic examination mean transvalvular gradient was 54.3 ± 6.42. We had no death during early or late postoperative period. Only one patient had pulmonary complications and long time of respiratory assistance because of his pulmonary pathology. The same patient had low cardiac output and wound infection. Early after surgery mean transprostethic gradient was 16.2 ± 3.44 and late postoperative was 15.9 ± 4.3. No patient had the severe patient-prothesis mismatch. Mean follow-up was 49 ± 20.26 months. During follow

  20. High corrosion-resistant fuel spacers

    International Nuclear Information System (INIS)

    Yoshida, Toshimi; Takase, Iwao; Ikeda, Shinzo; Masaoka, Isao; Nakajima, Junjiro.

    1986-01-01

    Purpose: To enable manufacturing BWR fuel spacers by prior-art production process, using a zirconium-base alloy having very excellent corrosion resistance. Method: A highly improved nodular-resistant, corrosion-resistant zirconium alloy is devised by adding a slight amount of niobium, titanium and vanadium to zircaloy, of which fuel spacers are produced. That is, there can be obtained an alloy having much more excellent nodular resistance than conventional zircaloy, and free from a large change in plasticity, workability, and weldability, by adding to zirconium about 1.5 % of tin, about 0.15 % of iron, about 0.05 % of chromium, about 0.05 % of nickel, and 0.05 to 0.5 % of at least one or two kinds of niobium, titanium and vanadium. Using this zirconium-base alloy can manufacture fuel spacers by the same manufacturing process, thus improving economy and reliability. (Kamimura, M.)

  1. Bovine annulus fibrosus cell lines isolated from intervertebral discs

    Directory of Open Access Journals (Sweden)

    Petra Kraus

    2016-12-01

    Full Text Available The adult bovine (Bos taurus intervertebral disc is primarily comprised of two major tissue types: The outer annulus fibrosus (AF and the central nucleus pulposus (NP. We isolated several primary cell lineages of passage (P 0 cells from the AF tissue omitting typically used enzymatic tissue digestion protocols. The cells grow past p10 without signs of senescence in DMEM + 10% FCS on 0.1% gelatin coated/uncoated surfaces of standard cell culture plates and survive freeze-thawing. Preliminary analysis of the AF derived cells for expression of the two structural genes Col1a1 and Col2a1 was performed by PISH recapitulating the expression observed in vivo.

  2. Opposing flow in square porous annulus: Influence of Dufour effect

    Energy Technology Data Exchange (ETDEWEB)

    Athani, Abdulgaphur, E-mail: abbu.bec@gmail.com [Dept. of Mechanical Engineering, Anjuman Institute of Technology & Management, Bhatkal (India); Al-Rashed, Abdullah A. A. A., E-mail: aa.alrashed@paaet.edu.kw [Dept. of Automotive and Marine Engineering Technology, College of Technological Studies, The Public Authority for Applied Education and Training (Kuwait); Khaleed, H. M. T., E-mail: khalid-tan@yahoo.com [Dept of Mechanical Engineering, Faculty of Engineering, Islamic University, Madinah Munawwarra (Saudi Arabia)

    2016-06-21

    Heat and mass transfer in porous medium is very important area of research which is also termed as double diffusive convection or thermo-solutal convection. The buoyancy ratio which is the ratio of thermal to concentration buoyancy can have negative values thus leading to opposing flow. This article is aimed to study the influence of Dufour effect on the opposing flow in a square porous annulus. The partial differential equations that govern the heat and mass transfer behavior inside porous medium are solved using finite element method. A three node triangular element is used to divide the porous domain into smaller elements. Results are presented with respect to geometric and physical parameters such as duct diameter ratio, Rayleigh number, radiation parameter etc. It is found that the heat transfer increase with increase in Rayleigh number and radiation parameter. It is observed that Dufour coefficient has more influence on velocity profile.

  3. Opposing flow in square porous annulus: Influence of Dufour effect

    International Nuclear Information System (INIS)

    Athani, Abdulgaphur; Al-Rashed, Abdullah A. A. A.; Khaleed, H. M. T.

    2016-01-01

    Heat and mass transfer in porous medium is very important area of research which is also termed as double diffusive convection or thermo-solutal convection. The buoyancy ratio which is the ratio of thermal to concentration buoyancy can have negative values thus leading to opposing flow. This article is aimed to study the influence of Dufour effect on the opposing flow in a square porous annulus. The partial differential equations that govern the heat and mass transfer behavior inside porous medium are solved using finite element method. A three node triangular element is used to divide the porous domain into smaller elements. Results are presented with respect to geometric and physical parameters such as duct diameter ratio, Rayleigh number, radiation parameter etc. It is found that the heat transfer increase with increase in Rayleigh number and radiation parameter. It is observed that Dufour coefficient has more influence on velocity profile.

  4. Critical heat flux determination in an annulus section

    International Nuclear Information System (INIS)

    Reyes C, C.A.

    1997-01-01

    The present report explains the phenomenon of Critical heat flux. The study of this physical phenomenon is carried out during the boiling of a liquid and is of supreme importance for the calculation and operation of a nuclear reactor even in the moderns generators of steam (thermoelectric and nucleoelectrics), industrial cooling and in all those industrial process that use a liquid subject to sources of heating and to conditions of work excessively high (temperatures and pressures) so that stay in operation in an appropriate manner and sure. Once well-known this value, the equipment used in these process works with a maximum heat that is smaller than the Critical Heat Flux. The study of the Critical Heat Flux has achieved important advances in the last years, mainly for the enormous obligation that in this moment involved the safety to world level, this has forced to researchers and designers of this type of equipment to center their attention in the obtaining of a correlation which of general way explains it. In this reports two correlations will be compared that they contribute to the evaluation of the Critical Heat Flux in annulus and that they try to be generals in this type of geometry, the Shah correlation's and the Katto correlation's. The same as most of the correlations, these have been calculated so that the fluid of work is water, although they have also been proven with others fluids. The results obtained in this report only will show the degree of advance which the investigation of this phenomenon has achieved in annulus and to low amounts of flow of liquid, like which they are in the Experimental Heat Transfer Circuit located in the Department of Physics of the National Institute of Nuclear Research. (Author)

  5. Fouling Resilient Perforated Feed Spacers for Membrane Filtration

    KAUST Repository

    Kerdi, Sarah

    2018-04-24

    The improvement of feed spacers with optimal geometry remains a key challenge for spiral-wound membrane systems in water treatment due to their impact on the hydrodynamic performance and fouling development. In this work, novel spacer designs are proposed by intrinsically modifying cylindrical filaments through perforations. Three symmetric perforated spacers (1-Hole, 2-Hole, and 3-Hole) were in-house 3D-printed and experimentally evaluated in terms of permeate flux, feed channel pressure drop and membrane fouling. Spacer performance is characterized and compared with standard no perforated (0-Hole) design under constant feed pressure and constant feed flow rate. Perforations in the spacer filaments resulted in significantly lowering the net pressure drop across the spacer filled channel. The 3-Hole spacer was found to have the lowest pressure drop (50% - 61%) compared to 0-Hole spacer for various average flow velocities. Regarding permeate flux production, the 0-Hole spacer produced 5.7 L.m-2.h-1 and 6.6 L.m-2.h-1 steady state flux for constant pressure and constant feed flow rate, respectively. The 1-Hole spacer was found to be the most efficient among the perforated spacers with 75% and 23% increase in permeate production at constant pressure and constant feed flow, respectively. Furthermore, membrane surface of 1-Hole spacer was found to be cleanest in terms of fouling, contributing to maintain higher permeate flux production. Hydrodynamic understanding of these perforated spacers is also quantified by performing Direct Numerical Simulation (DNS). The performance enhancement of these perforated spacers is attributed to the formation of micro-jets in the spacer cell that aided in producing enough unsteadiness/turbulence to clean the membrane surface and mitigate fouling phenomena. In the case of 1-Hole spacer, the unsteadiness intensity at the outlet of micro-jets and the shear stress fluctuations created inside the cells are higher than those observed with

  6. Report on reflood experiment of grid spacer effect

    International Nuclear Information System (INIS)

    Sugimoto, Jun; Murao, Yoshio

    1984-07-01

    Experiments were performed in order to clarify the effect of grid spacers on reflood heat transfer in PWR-LOCA. The flow pattern, the thermal responses and the water accumulation near the grid spacer were investigated by shifting the grid spacer at the midplane of the simulated core. Also tested is the effect of the thickness of the grid spacer wall on the reflood behavior. The heat transfer coefficient before the quenching was about 20 to 50 percent higher just above the grid spacer than just below the grid spacer. The decrease of the droplet diameter due to the grid spacer was observed in the droplet dispersed flow regime. In the slug flow regime, the grid spacer was rewetted early in the reflood transient and the increased water accumulation near the grid spacer was observed. Hence, the heat transfer enhancement due to the grid spacer is mainly attributed to the increased interfacial surface area of droplets in the dispersed flow and also to the increased film boiling heat transfer in the slug flow. The heat transfer enhancement tended to be larger with the larger thickness of the grid spacer. The simple model was developed for both the dispersed flow and slug flow regimes based on the present experimental results. The thermohydraulic behavior near the grid spacer was well calculated with the developed model. The further detailed information, however, is required for the improvement and the verification of the grid spacer model. (author)

  7. Nuclear reactor fuel assembly spacer grids

    International Nuclear Information System (INIS)

    Jabsen, F.S.

    1977-01-01

    Designs of nuclear reactor fuel assembly spacer grids for supporting and spacing fuel elements are described which do not utilize resilient grid plate protrusions in the peripheral band but retain the advantages inherent in the combination resilient and rigid protrusion cells. (U.K.)

  8. Pressure Drop Test of Hybrid Mixing Vane Spacer Grid

    Energy Technology Data Exchange (ETDEWEB)

    Oh, D. S.; Chang, S. K.; Kim, B. D.; Chun, S. Y.; Chun, T. H

    2007-08-15

    The pressure loss test has been accomplished in the test section containing 5x5 rod bundle with a length of 2 m including 3 spacer grids. The test has been performed for the 5 kinds of spacer grids to compare the pressure loss characteristics: 1. Plain spacer grid which has the same body of the Hybrid but without vane (Plain), 2. Hybrid Vane spacer grid (Hybrid), 3. Hybrid-SC spacer grid which is constructed with coined, chamfered strip and is fabricated by spot welding, 4. Hybrid-LC spacer grid which is constructed with coined, chamfered strip and is fabricated by line welding along intersection line, 5. Westinghouse spacer grid with split vane (Plus-7). The pressure loss coefficient of the Plain, Hybrid, Hybrid-SC, Hybrid-LC, and Plus-7 spacer grid is 0.93, 1.15, 1.02, 1.04, and 1.08, respectively.

  9. Hydraulic Design Criteria for Spacer Grids of Nuclear Fuel Element

    International Nuclear Information System (INIS)

    Juanico, Luis; Brasnarof, Daniel

    2000-01-01

    In this paper a hydraulic model for calculating the pressure drop on the CARA spacer grids is extended.This model is validated and feedback from experimental hydraulic test performed in a low pressure loop.The importance of the spacer grid geometric parameter (that is, its thickness and length, the number and kind of their fix spacer), developing hydraulic design criteria for spacer grid on fuel element

  10. Tank 16 Annulus Cleanout Analysis Doses at Seepline from Transport of Residual Tc-99 Wastes

    International Nuclear Information System (INIS)

    Collard, L.B.

    1999-01-01

    An analysis of residual Tc-99 in the Tank 16 annulus was conducted to assess the potential benefit from cleaning the annulus. One analysis was performed for the as-is case to determine seepline doses if no clean out occurs. Another analysis was performed assuming that ninety percent of existing contaminants are removed. Characterization data for samples retrieved from the annulus were used in the analysis. Only Tc-99 was analyzed because preliminary modeling identified it as the highest dose contributor. The effect of residual waste in piping was not analyzed

  11. A non-electrostatic spacer for aerosol delivery

    DEFF Research Database (Denmark)

    Bisgaard, H; Anhøj, J; Klug, B

    1995-01-01

    A pear shaped non-electrostatic spacer, composed of steel with a volume of 250 ml and equipped with a facemask containing integrated inlet and outlet valves for inspiration and expiration, was compared with three plastic spacers. The plastic spacers were primed with repeated puffs from a budesonide...

  12. Autoclaved metal-on-cement spacer versus static spacer in two-stage revision in periprosthetic knee infection

    Directory of Open Access Journals (Sweden)

    Yu-Pin Chen

    2016-01-01

    Conclusions: The autoclaved metal-on-cement spacer is an effective and simple method for two-stage re-implantation of a periprosthetic knee infection. Through this spacer, the good interim ROM can be achieved without the additional cost of prefabricated molds or new polyethylene tibial inserts. In addition, ROM after re-implantation is better than that with static spacers.

  13. A technique of aortic annulus enlargement with a Freestyle stentless bioprosthesis.

    Science.gov (United States)

    Bical, Olivier M; Nutu, Ovidiu; Deleuze, Philippe

    2012-02-01

    We describe our surgical technique to manage a small aortic annulus during aortic valve replacement. Starting with the posterior annular enlargement incision described by Manouguian, a stentless porcine aortic root, with excision of the left and right porcine coronary segments and conservation of the mural wall (Freestyle MS design, Medtronic, Minneapolis, MN ), was used. The Freestyle bioprosthesis enlarges the aortic annulus using a direct suture of the valve on the enlarged annulus, and the aorta is closed by a direct suture of the mural wall of the bioprosthesis. Therefore, the aortic annulus enlargement is made only using the aortic bioprosthesis, without other material. Copyright © 2012 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  14. A Biodegradable Glue for Annulus Closure Evaluation of Strength and Endurance

    NARCIS (Netherlands)

    Vergroesen, Pieter-Paul A.; Bochynska, Agnieszka I.; Emanuel, Kaj S.; Sharifi, Shahriar; Kingma, Idsart; Grijpma, Dirk W.; Smit, Theodoor H.

    2015-01-01

    Study Design. A biodegradable glue was biomechanically tested for annulus closure using nondegenerated goat intervertebral discs. Ultimate strength and endurance tests were performed using native and punctured discs as positive and negative controls, respectively. Objective. The aim of this study

  15. Identification of rabbit annulus fibrosus-derived stem cells.

    Directory of Open Access Journals (Sweden)

    Chen Liu

    Full Text Available Annulus fibrosus (AF injuries can lead to substantial deterioration of intervertebral disc (IVD which characterizes degenerative disc disease (DDD. However, treatments for AF repair/regeneration remain challenging due to the intrinsic heterogeneity of AF tissue at cellular, biochemical, and biomechanical levels. In this study, we isolated and characterized a sub-population of cells from rabbit AF tissue which formed colonies in vitro and could self-renew. These cells showed gene expression of typical surface antigen molecules characterizing mesenchymal stem cells (MSCs, including CD29, CD44, and CD166. Meanwhile, they did not express negative markers of MSCs such as CD4, CD8, and CD14. They also expressed Oct-4, nucleostemin, and SSEA-4 proteins. Upon induced differentiation they showed typical osteogenesis, chondrogenesis, and adipogenesis potential. Together, these AF-derived colony-forming cells possessed clonogenicity, self-renewal, and multi-potential differentiation capability, the three criteria characterizing MSCs. Such AF-derived stem cells may potentially be an ideal candidate for DDD treatments using cell therapies or tissue engineering approaches.

  16. Heterogeneous diversity of spacers within CRISPR

    Science.gov (United States)

    Deem, Michael; He, Jiankui

    2011-03-01

    Clustered regularly interspaced short palindromic repeats (CRISPR) in bacterial and archaeal DNA have recently been shown to be a new type of anti-viral immune system in these organisms. We here study the diversity of spacers in CRISPR under selective pressure. We propose a population dynamics model that explains the biological observation that the leader-proximal end of CRISPR is more diversified and the leader-distal end of CRISPR is more conserved. This result is shown to be in agreement with recent experiments. Our results show that the CRISPR spacer structure is influenced by and provides a record of the viral challenges that bacteria face. 1) J. He and M. W. Deem, Phys. Rev. Lett. 105 (2010) 128102

  17. Honeycomb spacer crush stength test results

    Energy Technology Data Exchange (ETDEWEB)

    Leader, D.R.

    1993-09-15

    This report discusses aluminum honeycomb spacers, which are used as an energy absorbent material in shipping packages for off site shipment of radioactive materials and which were ordered in two crush strengths, 1,000 psi and 2,000 psi for use in drop tests requested by the Packaging and Transportation group as part of the shipping container rectification process. Both the group as part of the shipping container rectification process. Both the vendor and the SRTC Materials Laboratory performed crush strength measurements on test samples made from the material used to fabricate the actual spacers. The measurements of crush strength made in the SRTC Materials Laboratory are within 100 psi of the measurements made by the manufacturer for all samples tested and all test measurements are within 10% of the specified crush strength, which is acceptable to the P&T group for the planned tests.

  18. Antibiotic impregnated total femur spacers: a technical tip

    Directory of Open Access Journals (Sweden)

    Colin D. Canham, MD

    2018-03-01

    Full Text Available Simultaneous prosthetic joint infection of ipsilateral hip and knee arthroplasties is often accompanied by significant bone loss and presents a challenging reconstructive problem. Two-stage reconstruction is favored and requires the placement of a total femur spacer, which is not a commercially available device. We describe a surgical technique, reporting on 2 cases in which a customized total femur antibiotic impregnated spacer was created by combining an articulating knee spacer and an articulating hip spacer with a reinforced cement dowel construct connecting the 2 spacers. Custom total femoral spacers are useful in the management of infected femoral megaprostheses and cases with ipsilateral injected hip and knee arthroplasties and severe femoral bone loss. Keywords: total femur spacer, revision arthroplasty, total hip arthroplasty, total knee arthroplasty, prosthetic joint infection

  19. Influence of spacer length on heparin coupling efficiency and fibrinogen adsorption of modified titanium surfaces

    Directory of Open Access Journals (Sweden)

    Gbureck Uwe

    2007-07-01

    Full Text Available Abstract Background Chemical bonding of the drug onto surfaces by means of spacer molecules is accompanied with a reduction of the biological activity of the drug due to a constricted mobility since normally only short spacer molecule like aminopropyltrimethoxysilane (APMS are used for drug coupling. This work aimed to study covalent attachment of heparin to titanium(oxide surfaces by varying the length of the silane coupling agent, which should affect the biological potency of the drug due to a higher mobility with longer spacer chains. Methods Covalent attachment of heparin to titanium metal and TiO2 powder was carried out using the coupling agents 3-(Trimethoxysilyl-propylamine (APMS, N- [3-(Trimethoxysilylpropyl]ethylenediamine (Diamino-APMS and N1- [3-(Trimethoxy-silyl-propyl]diethylenetriamine (Triamino-APMS. The amount of bound coupling agent and heparin was quantified photometrically by the ninhydrin reaction and the tolidine-blue test. The biological potency of heparin was determined photometrically by the chromogenic substrate Chromozym TH and fibrinogen adsorption to the modified surfaces was researched using the QCM-D (Quartz Crystal Microbalance with Dissipation Monitoring technique. Results Zeta-potential measurements confirmed the successful coupling reaction; the potential of the unmodified anatase surface (approx. -26 mV shifted into the positive range (> + 40 mV after silanisation. Binding of heparin results in a strongly negatively charged surface with zeta-potentials of approx. -39 mV. The retaining biological activity of heparin was highest for the spacer molecule Triamino-APMS. QCM-D measurements showed a lower viscosity for adsorbed fibrinogen films on heparinised surfaces by means of Triamino-APMS. Conclusion The remaining activity of heparin was found to be highest for the covalent attachment with Triamino-APMS as coupling agent due to the long chain of this spacer molecule and therefore the highest mobility of the drug

  20. Kinetics of liquid annulus formation and capillary forces.

    Science.gov (United States)

    Rabinovich, Y I; Singh, A; Hahn, M; Brown, S; Moudgil, B

    2011-11-15

    The dependence of the capillary adhesion force F(cap) between a silica microsphere and a flat silica surface versus a time period t of the samples' contact (i.e., dwell-in time) is experimentally investigated using atomic force microscopy (AFM). F(cap) was found to be dependent on t if the humidity was >30-35%. This dependence is exponential, with decay (characteristic) times of ∼10 s. It is suggested that the kinetics of the adhesion process are related to the growth of the water annulus between surfaces. Furthermore, we propose that the growth kinetics has two components: (1) water vapor diffusion from the surrounding humid media into the gap between samples and (2) water drainage from the gap. The theory of diffusion through thin pores (i.e., gaps) is developed, and analytical formulas are obtained for the dependence of the meniscus radius r versus time t. However, the experimental dependence of F(cap) versus t and, consequently, r versus t obtained in this article disagrees with the theoretical prediction by several orders of magnitude. Similar results were obtained from the literature data for capillary forces between an AFM cantilever tip and a flat surface. Possible reasons for the deviation from diffusion theory are suggested: surface and Knudsen regimes of vapor diffusion, nonsteady state vapor flow, and tortuosity. Taking into account the viscous drainage of water from the multilayer gap can explain the experimental kinetics of bridge formation, but only if the viscosity of the adjacent multilayer of water is several orders of magnitude larger than the bulk viscosity.

  1. Quantification of aortic annulus in computed tomography angiography: Validation of a fully automatic methodology.

    Science.gov (United States)

    Gao, Xinpei; Boccalini, Sara; Kitslaar, Pieter H; Budde, Ricardo P J; Attrach, Mohamed; Tu, Shengxian; de Graaf, Michiel A; Ondrus, Tomas; Penicka, Martin; Scholte, Arthur J H A; Lelieveldt, Boudewijn P F; Dijkstra, Jouke; Reiber, Johan H C

    2017-08-01

    Automatic accurate measuring of the aortic annulus and determination of the optimal angulation of X-ray projection are important for the trans-catheter aortic valve replacement (TAVR) procedure. The objective of this study was to present a novel fully automatic methodology for the quantification of the aortic annulus in computed tomography angiography (CTA) images. CTA datasets of 26 patients were analyzed retrospectively with the proposed methodology, which consists of a knowledge-based segmentation of the aortic root and detection of the orientation and size of the aortic annulus. The accuracy of the methodology was determined by comparing the automatically derived results with the reference standard obtained by semi-automatic delineation of the aortic root and manual definition of the annulus plane. The difference between the automatic annulus diameter and the reference standard by observer 1 was 0.2±1.0mm, with an inter-observer variability of 1.2±0.6mm. The Pearson correlation coefficient for the diameter was good (0.92 for observer 1). For the first time, a fully automatic tool to assess the optimal projection curves was presented and validated. The mean difference between the optimal projection curves calculated based on the automatically defined annulus plane and the reference standard was 6.4° in the cranial/caudal (CRA/CAU) direction. The mean computation time was short with around 60s per dataset. The new fully automatic and fast methodology described in this manuscript not only provided precise measurements about the aortic annulus size with results comparable to experienced observers, but also predicted optimal X-ray projection curves from CTA images. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Numerical prediction on turbulent heat transfer of a spacer ribbed fuel rod for high temperature gas-cooled reactors

    International Nuclear Information System (INIS)

    Takase, Kazuyuki

    1994-11-01

    The turbulent heat transfer of a fuel rod with three-dimensional trapezoidal spacer ribs for high temperature gas-cooled reactors was analyzed numerically using the k-ε turbulence model, and investigated experimentally using a simulated fuel rod under the helium gas condition of a maximum outlet temperature of 1000degC and pressure of 4MPa. From the experimental results, it found that the turbulent heat transfer coefficients of the fuel rod were 18 to 80% higher than those of a concentric smooth annulus at a region of Reynolds number exceeding 2000. On the other hand, the predicted average Nusselt number of the fuel rod agreed well with the heat transfer correlation obtained from the experimental data within a relative error of 10% with Reynolds number of more than 5000. It was verified that the numerical analysis results had sufficient accuracy. Furthermore, the numerical prediction could clarify quantitatively the effects of the heat transfer augmentation by the spacer rib and the axial velocity increase due to a reduction in the annular channel cross-section. (author)

  3. Sequence and structure correlation of human ribosomal transcribed spacers.

    Science.gov (United States)

    Gonzalez, I L; Chambers, C; Gorski, J L; Stambolian, D; Schmickel, R D; Sylvester, J E

    1990-03-05

    We report the sequences of the transcribed spacers of human rRNA that now allow us to piece together the entire primary transcript sequence of approximately 13.3 x 10(3) base-pairs. Comparison of transcribed spacer sequences with those of variable regions of rRNA and with those of the non-transcribed spacers supports the hypothesis that the variable regions are descended from transcribed spacers. Nucleotide sequence-derived secondary structures for the 5' external transcribed spacer and for internal transcribed spacers 1 and 2 match both the sizes and shapes of the structures that were visualized 15 years ago on electron micrographs. Parts of these structures are conserved in mammals and may be related to transcript processing.

  4. Preclinical evaluation of bioabsorbable polyglycolic acid spacer for particle therapy.

    Science.gov (United States)

    Akasaka, Hiroaki; Sasaki, Ryohei; Miyawaki, Daisuke; Mukumoto, Naritoshi; Sulaiman, Nor Shazrina Binti; Nagata, Masaaki; Yamada, Shigeru; Murakami, Masao; Demizu, Yusuke; Fukumoto, Takumi

    2014-12-01

    To evaluate the efficacy and safety of a polyglycolic acid (PGA) spacer through physical and animal experiments. The spacer was produced with surgical suture material made of PGA, forming a 3-dimensional nonwoven fabric. For evaluation or physical experiments, 150-MeV proton or 320-MeV carbon-ion beams were used to generate 60-mm width of spread-out Bragg peak. For animal experiments, the abdomens of C57BL/6 mice, with or without the inserted PGA spacers, were irradiated with 20 Gy of carbon-ion beam (290 MeV) using the spread-out Bragg peak. Body weight changes over time were scored, and radiation damage to the intestine was investigated using hematoxylin and eosin stain. Blood samples were also evaluated 24 days after the irradiation. Long-term thickness retention and safety were evaluated using crab-eating macaques. No chemical or structural changes after 100 Gy of proton or carbon-ion irradiation were observed in the PGA spacer. Water equivalency of the PGA spacer was equal to the water thickness under wet condition. During 24 days' observation after 20 Gy of carbon-ion irradiation, the body weights of mice with the PGA spacer were relatively unchanged, whereas significant weight loss was observed in those mice without the PGA spacer (P<.05). In mice with the PGA spacer, villus and crypt structure were preserved after irradiation. No inflammatory reactions or liver or renal dysfunctions due to placement of the PGA spacer were observed. In the abdomen of crab-eating macaques, thickness of the PGA spacer was maintained 8 weeks after placement. The absorbable PGA spacer had water-equivalent, bio-compatible, and thickness-retaining properties. Although further evaluation is warranted in a clinical setting, the PGA spacer may be effective to stop proton or carbon-ion beams and to separate normal tissues from the radiation field. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. A non-electrostatic spacer for aerosol delivery

    DEFF Research Database (Denmark)

    Bisgaard, H; Anhøj, J; Klug, B

    1995-01-01

    pressurised metered dose inhaler (p-MDI) to minimise the electrostatic charge on the plastic. The procedure prolonged the half life (t1/2) of the aerosol in the Nebuhaler from nine to 32 seconds. A normal cleaning procedure reduced the aerosol t1/2 back to baseline. The t1/2 of the aerosol in the metal spacer...... younger than 4 years. The improved dose delivery from the small volume non-electrostatic spacer is probably related to the non-electrostatic spacer material and the valves which assured unidirectional airflow from the spacer without adding any dead space in the inspiratory channel. The non-electro-static...

  6. Development of structural technology for a high performance spacer grid

    International Nuclear Information System (INIS)

    Song, Kee Nam; Kim, H. K.; Kang, H. S.

    2003-03-01

    A spacer grid in a LWR fuel assembly is a key structural component to support fuel rods and to enhance the heat transfer from the fuel rod to the coolant. In this research, the main research items are the development of inherent and high performance spacer grid shapes, the establishment of mechanical/structural analysis and test technology, and the set-up of basic test facilities for the spacer grid. The main research areas and results are as follows. 1. 14 different spacer grid candidates have been invented and applied for domestic and US patents. Among the candidates six are chosen from the patent. 2. Two kinds of spacer grids are finally selected for the advanced LWR fuel after detailed performance tests on the candidates and commercial spacer grids from a mechanical/structural point of view. According to the test results the features of the selected spacer grids are better than those of the commercial spacer grids. 3. Four kinds of basic test facilities are set up and the relevant test technologies are established. 4. Mechanical/structural analysis models and technology for spacer grid performance are developed and the analysis results are compared with the test results to enhance the reliability of the models

  7. Design of modified annulus air sampling system for the detection of leakage in waste transfer line

    International Nuclear Information System (INIS)

    Deokar, U.V; Khot, A.R.; Mathew, P.; Ganesh, G.; Tripathi, R.M.; Srivastava, Srishti

    2018-01-01

    Various liquid waste streams are generated during the operation of reprocessing plant. The High Level (HL), Intermediate Level (IL) and Low Level (LL) liquid wastes generated, are transferred from reprocessing plant to Waste Management Facility. These respective waste streams are transferred through pipe-in-pipe lines along the shielded concrete trench. For detection of radioactive leakage from primary waste transfer line into secondary line, sampling of the annulus air between the two pipes is carried out. The currently installed pressurized annulus air sampling system did not have online leakage detection provision. Hence, there are chances of personal exposure and airborne activity in the working area. To overcome these design flaws, free air flow modified online annulus air sampling system with more safety features is designed

  8. Experimental study of the steady natural convection in a horizontal annulus with irregular boundaries

    International Nuclear Information System (INIS)

    Boyd, R.D.

    1980-01-01

    The natural convective heat transfer across an annulus with irregular boundaries was studied using a Mach-Zehnder interferometer. The annulus was formed by an inner hexagonal cylinder and an outer concentric circular cylinder. This configuration models, in two dimensions, a liquid metal fast breeder reactor spent fuel subassembly inside a shipping container. During the test, the annulus was filled with a single gas, either neon, air, argon, krypton, or xenon, at a pressure of about 0.5 MPa. From temperature measurements, both local and mean Nusselt numbers (Nu/sub Δ/) at the surface of the inner cylinder were evaluated, with the mean Rayleigh number (anti Ra/sub Δ/) varying from 4.54 x 10 4 to 0.915 x 10 6 (Δ is the local gas width). The data correlation for the mean Nusselt and Rayleigh numbers is given by anti Nu/sub Δ/ = 0.183 anti Ra/sub Δ/ 0 310

  9. Technical Information to Support Double Shell Tank (DST) Emergency Annulus Pumping [SEC 1 and 2

    Energy Technology Data Exchange (ETDEWEB)

    REBERGER, D.W.

    2000-09-14

    This document provides the design calculations for the DST Annulus Emergency Pumping Project. This document also contains essential information relative to DST annulus emergency pumping that may not be found in other documents. This information consists of the following: Index drawing for annulus pumping; References to the Acceptance Test Report, DST Emergency Pumping Guide, Time Deployment study, etc.; Statements of work; and Reference CEIS and RMIS numbers. A Vendor Information document, VI-50121, is not included in this document, but a copy can be obtained by contacting Document Control Services. This document contains various information regarding the Hydrostar pumps, such as the air motor, cylinder size, pump installation and operation manual. It also contains information regarding the Flygt BS2060 submersible pump, such as parts list, pump handling, preventative maintenance, overhaul and repair. In addition, this document also has information on 3-way PM ball valves, electrical skid components and the alternate Gurman-Rupp stainless steel submersible pump.

  10. Regimes of Axisymmetric Flow and Scaling Laws in a Rotating Annulus with Local Convective Forcing

    Directory of Open Access Journals (Sweden)

    Susie Wright

    2017-07-01

    Full Text Available We present a numerical study of axisymmetric flow in a rotating annulus in which local thermal forcing, via a heated annular ring on the outside of the base and a cooled circular disk in the centre of the top surface, drives convection. This new configuration is a variant of the classical thermally-driven annulus, where uniform heating and cooling are applied through the outer and inner sidewalls respectively. The annulus provides an analogue to a planetary circulation and the new configuration, with its more relaxed vertical thermal boundary conditions, is expected to better emulate vigorous convection in the tropics and polar regions as well as baroclinic instability in the mid-latitude baroclinic zone. Using the Met Office/Oxford Rotating Annulus Laboratory (MORALS code, we have investigated a series of equilibrated, two dimensional axisymmetric flows across a large region of parameter space. These are characterized in terms of their velocity and temperature fields. When rotation is applied several distinct flow regimes may be identified for different rotation rates and strengths of differential heating. These regimes are defined as a function of the ratio of the horizontal Ekman layer thickness to the non-rotating thermal boundary layer thickness and are found to be similar to those identified in previous annulus experiments. Convection without rotation is also considered and the scaling of the heat transport with Rayleigh number is calculated. This is then compared with existing work on the classical annulus as well as horizontal and Rayleigh-Bénard convection. As with previous studies on both rotating and non-rotating convection the system’s behaviour is found to be aspect ratio dependent. This dependence is seen in the scaling of the non-rotating Nusselt number and in transitions between regimes in the rotating case although further investigation is required to fully explain these observations.

  11. APPLICATIONS OF SPACERS MADE WITH DOUBLE BAR RASCHEL MACHINE

    Directory of Open Access Journals (Sweden)

    DÍAZ-GARCÍA Pablo

    2016-05-01

    Full Text Available Nowadays, textile technologies develop to adapt their different techniques for creating new products for the different sectors of application every day. Particularly, warp knitted fabrics and warp-knitting technology have applications in all different groups of technical textiles. It could be the most applied technique, the most versatile technology to develop new textile products for the new textile market. Warp knitted fabrics play the most important role among the technical textile fabrics. This technology is used in different product groups such as mobile textiles (car seat covers, dashboard cover, industrial textiles (composites, medical textiles (anti-decubitus blankets, sports textiles and foundation garments (bra cups, pads for swimwear. This study presents some examples of the application of this technology in some markets Within the market of technical textile, medical textile has an increasing relevance and knitted fabrics and knitting technology, at the same time, play a very important role in the fields of technical and medical textiles. Studies have demonstrated that knitted structures possess excellent mechanical properties and can promote more effective regenerative medicine, tissue repair, ligament, tendon cartilage, reconstruction, etc. The aim of this paper is to present different possibilities of textiles developed with this kind of structures, to present different alternatives, different examples of products obtained with this kind of textile structure combined with the correct kind of textile fiber. In this kind of technology, double-bar Raschel machines used for producing three-dimensional textiles, spacers, play an important role.

  12. [Large mitral annulus myxoma presenting with syncope: Report of one case].

    Science.gov (United States)

    Vega, Julián; Gabrielli, Luigi; Olivares, Gabriel; Córdova, Samuel; Méndez, Manuel; González, Rodrigo

    2016-12-01

    We report a 23-year-old woman, with three recent exertional syncopes. Transthoracic (TTE) and transesophageal (TEE) echocardiography found a large heterogeneous mass (38 x 35 mm) arising from the posterior mitral annulus, protruding in systole through the left ventricular outflow tract (LVOT). Heart MRI confirmed the echocardiography findings, suggesting a cardiac myxoma. Cardiac surgery accomplished the complete resection of the lesion, confirming a mass arising from the posterior mitral annulus and preserving mitral anatomy and function. Pathology was positive for a myxoma. Uneventful evolution allowed the discharge of the patient at the fifth postoperative day. Control TTE discarded any complication.

  13. Extraordinary acoustic transmission through annuluses in air and its applications in acoustic beam splitter and concentrator

    International Nuclear Information System (INIS)

    Ge, Yong; Liu, Shu-sen; Yuan, Shou-qi; Xia, Jian-ping; Guan, Yi-jun; Sun, Hong-xiang; Zhang, Shu-yi

    2016-01-01

    We report an extraordinary acoustic transmission through two layer annuluses made of metal cylinders in air both numerically and experimentally. The effect arises from the enhancement and reconstruction of the incident source induced by different Mie-resonance modes of the annuluses. The proposed system takes advantages of the consistency in the waveform between the input and output waves, the high amplitude amplification of output waves, and the easy adjustment of structure. More interestingly, we investigate the applications of the extraordinary acoustic transmission in the acoustic beam splitter and acoustic concentrator. Our finding should have an impact on ultrasonic applications.

  14. Nuclear reactor spring strip grid spacer

    International Nuclear Information System (INIS)

    Patterson, J.F.; Flora, B.S.

    1980-01-01

    An improved and novel grid spacer was developed for use in nuclear reactor fuel assemblies. It is comprised of a series of intersecting support strips and a peripheral support band attached to the ends of the support strips. Each of the openings into which the fuel element is inserted has a number of protruding dimples and springs extending in different directions. The dimples coact with the springs to secure the fuel rods in the openings. Compared with previous designs, this design gives more positive alignment of the support stips while allowing greater flexibility to counterbalance the effects of thermal expansion. The springs are arranged in alternating directions so that the reaction forces tend to counterbalance each other, which in turn minimizes the reaction loads on the supporting structure. (D.N.)

  15. Salvage of Infected Nasal Reconstruction with a Polymethyl Methacrylate Spacer.

    Science.gov (United States)

    Cavadas, Pedro C; Thione, Alessandro; Pacheco, Yvan D

    2017-07-01

    Total nasal reconstruction is a challenging multistage procedure. Infections can destroy the cartilage framework and seriously compromise the result. The use of polymethyl methacrylate with antibiotics as a spacer has been described in the treatment of skeletal infections. Using this same principle, the use of a polymethyl methacrylate with antibiotics spacer for an infected nasal reconstruction is reported in a clinical case.

  16. Intergenic spacer length variants in Old Portuguese bread wheat ...

    Indian Academy of Sciences (India)

    2011-08-19

    Aug 19, 2011 ... and the termination of the transcription (McMullen et al. 1986; Suzuki et al. 1996; Abdulova and Ananiev 2003). The non-coding rDNA spacers (IGS and the internal transcribed spacer (ITS)) could be substantially variable in size due to differences in the number of repetitive elements among the closely ...

  17. ATLAS barrel hadron tile calorimeter: spacers plates mass production

    International Nuclear Information System (INIS)

    Artikov, A.M.; Budagov, Yu.A.; Khubua, J.

    1999-01-01

    In this article we expose the main problems of the mass production of the so-called 'spacer plates' for the ATLAS Barrel Hadron Tile Calorimeter. We describe all practical solutions of these problems. Particularly we present the measurement procedures and calculation schemes we used for the spacers dimensions determination. The results of the calculations are presented

  18. PCR-Internal Transcribed Spacer (ITS) genes sequencing and ...

    African Journals Online (AJOL)

    Methods: DNA extraction, purification, amplification and sequencing of Internal Transcribed Spacer (ITS) genes were per- formed using ... Keywords: Internal transcribed spacer genes, phylogenetic, genetic relationship, clinical and environmental fungi, HIV-TB. ... Nigeria. An Ethical clearance was obtained from the Eth-.

  19. CFD application to advanced design for high efficiency spacer grid

    International Nuclear Information System (INIS)

    Ikeda, Kazuo

    2014-01-01

    Highlights: • A new LDV was developed to investigate the local velocity in a rod bundle and inside a spacer grid. • The design information that utilizes for high efficiency spacer grid has been obtained. • CFD methodology that predicts flow field in a PWR fuel has been developed. • The high efficiency spacer grid was designed using the CFD methodology. - Abstract: Pressurized water reactor (PWR) fuels have been developed to meet the needs of the market. A spacer grid is a key component to improve thermal hydraulic performance of a PWR fuel assembly. Mixing structures (vanes) of a spacer grid promote coolant mixing and enhance heat removal from fuel rods. A larger mixing vane would improve mixing effect, which would increase the departure from nucleate boiling (DNB) benefit for fuel. However, the increased pressure loss at large mixing vanes would reduce the coolant flow at the mixed fuel core, which would reduce the DNB margin. The solution is to develop a spacer grid whose pressure loss is equal to or less than the current spacer grid and that has higher critical heat flux (CHF) performance. For this reason, a requirement of design tool for predicting the pressure loss and CHF performance of spacer grids has been increased. The author and co-workers have been worked for development of high efficiency spacer grid using Computational Fluid Dynamics (CFD) for nearly 20 years. A new laser Doppler velocimetry (LDV), which is miniaturized with fiber optics embedded in a fuel cladding, was developed to investigate the local velocity profile in a rod bundle and inside a spacer grid. The rod-embedded fiber LDV (rod LDV) can be inserted in an arbitrary grid cell instead of a fuel rod, and has the advantage of not disturbing the flow field since it is the same shape as a fuel rod. The probe volume of the rod LDV is small enough to measure spatial velocity profile in a rod gap and inside a spacer grid. According to benchmark experiments such as flow velocity

  20. Numerical investigation of heat transfer in annulus laminar flow of multi tubes-in-tube helical coil

    Science.gov (United States)

    Nada, S. A.; Elattar, H. F.; Fouda, A.; Refaey, H. A.

    2018-03-01

    In the present study, a CFD analysis using ANSYS-FLUENT 14.5 CFD package is used to investigate the characteristics of heat transfer of laminar flow in annulus formed by multi tubes in tube helically coiled heat exchanger. The numerical results are validated by comparison with previous experimental data and fair agreements were existed. The influences of the design and operation parameters such as heat flux, Reynolds numbers and annulus geometry on the heat transfer characteristics are investigated. Different annulus of different numbers of inner tubes, specifically 1, 2, 3, 4 and 5 tubes, are tested. The Results showed that for all the studied annulus, the heat flux has no effect on the Nusselt number and compactness parameter. The annulus formed by using five inner tubes showed the best heat transfer performance and compactness parameter. Correlation of predicting Nusselt number in terms of Reynolds number and number of inner tubes are presented.

  1. Cas4 Facilitates PAM-Compatible Spacer Selection during CRISPR Adaptation

    Directory of Open Access Journals (Sweden)

    Sebastian N. Kieper

    2018-03-01

    Full Text Available Summary: CRISPR-Cas systems adapt their immunological memory against their invaders by integrating short DNA fragments into clustered regularly interspaced short palindromic repeat (CRISPR loci. While Cas1 and Cas2 make up the core machinery of the CRISPR integration process, various class I and II CRISPR-Cas systems encode Cas4 proteins for which the role is unknown. Here, we introduced the CRISPR adaptation genes cas1, cas2, and cas4 from the type I-D CRISPR-Cas system of Synechocystis sp. 6803 into Escherichia coli and observed that cas4 is strictly required for the selection of targets with protospacer adjacent motifs (PAMs conferring I-D CRISPR interference in the native host Synechocystis. We propose a model in which Cas4 assists the CRISPR adaptation complex Cas1-2 by providing DNA substrates tailored for the correct PAM. Introducing functional spacers that target DNA sequences with the correct PAM is key to successful CRISPR interference, providing a better chance of surviving infection by mobile genetic elements. : Kieper et al. demonstrate that the ubiquitous protein Cas4 assists Cas1 and Cas2 in the selection of new CRISPR spacers with a PAM licensing efficient CRISPR interference. Keywords: CRISPR adaptation, Cas4, spacer acquisition, type I-D CRISPR-Cas system

  2. Design, Synthesis and Hydrolytic Behavior of Mutual Prodrugs of NSAIDs with Gabapentin Using Glycol Spacers

    Directory of Open Access Journals (Sweden)

    Hiba Najeh Alsaad

    2012-10-01

    Full Text Available The free –COOH present in NSAIDs is thought to be responsible for the GI irritation associated with all traditional NSAIDs. Exploitation of mutual prodrugs is an approach wherein the NSAID is covalently bounded to a second pharmacologically active carrier/drug with the ultimate aim of reducing the gastric irritation. In this study some NSAIDs were conjugated with gabapentin via ester bonds using glycol spacers with the expectation of reducing gastric adverse effects and obtaining synergistic analgesic effects. The kinetics of ester hydrolysis were studied in two different non enzymatic buffer solutions at pH 1.2 and 7.4, as well as in 80% human plasma using HPLC with chloroform -methanol as mobile phase. Compounds 9a–c with ethylene glycol spacers showed significant stability at buffer solutions with half lives ranging from about 8–25 h, while the underwent a reasonable plasma hydrolysis (49%–88% in 2 h. Compound 9d with a propylene glycol spacer shows a higher rate of enzymatic hydrolysis than the corresponding ethylene glycol compound 9c. The result of compounds 9a-c indicate that these compounds may be stable during their passage through the GIT until reaching the blood circulation.

  3. Design, synthesis and hydrolytic behavior of mutual prodrugs of NSAIDs with gabapentin using glycol spacers.

    Science.gov (United States)

    Mahdi, Monther Faisal; Alsaad, Hiba Najeh

    2012-10-12

    The free –COOH present in NSAIDs is thought to be responsible for the GI irritation associated with all traditional NSAIDs. Exploitation of mutual prodrugs is an approach wherein the NSAID is covalently bounded to a second pharmacologically active carrier/drug with the ultimate aim of reducing the gastric irritation. In this study some NSAIDs were conjugated with gabapentin via ester bonds using glycol spacers with the expectation of reducing gastric adverse effects and obtaining synergistic analgesic effects. The kinetics of ester hydrolysis were studied in two different non enzymatic buffer solutions at pH 1.2 and 7.4, as well as in 80% human plasma using HPLC with chloroform -methanol as mobile phase. Compounds 9a–c with ethylene glycol spacers showed significant stability at buffer solutions with half lives ranging from about 8–25 h, while the underwent a reasonable plasma hydrolysis (49%–88%) in 2 h. Compound 9d with a propylene glycol spacer shows a higher rate of enzymatic hydrolysis than the corresponding ethylene glycol compound 9c. The result of compounds 9a-c indicate that these compounds may be stable during their passage through the GIT until reaching the blood circulation.

  4. On the Use of Biaxial Properties in Modeling Annulus as a Holzapfel-Gasser-Ogden Material

    Directory of Open Access Journals (Sweden)

    Narjes eMomeni Shahraki

    2015-06-01

    Full Text Available Besides the biology, stresses and strains within the tissue greatly influence the location of damage initiation and mode of failure in an intervertebral disc. Finite element models of a functional spinal unit (FSU that incorporate reasonably accurate geometry and appropriate material properties are suitable to investigate such issues. Different material models and techniques have been used to model the anisotropic annulus fibrosus, but the abilities of these models to predict damage initiation in the annulus and to explain clinically observed phenomena are unclear. In this study a hyperelastic anisotropic material model for the annulus with two different sets of material constants, experimentally determined using uniaxial and biaxial loading conditions, were incorporated in a 3D finite element model of a ligamentous FSU. The purpose of the study was to highlight the biomechanical differences (e.g., intradiscal pressure, motion, forces, stresses and strains, etc. due to the dissimilarity between the two sets of material properties (uniaxial and biaxial. Based on the analyses, the biaxial constants simulations resulted in better agreements with the in-vitro and in-vivo data, and thus are more suitable for future damage analysis and failure prediction of the annulus under complex multiaxial loading conditions.

  5. Calculation of laminar incompressible fluid flow and heat transfer during spherical annulus filling

    International Nuclear Information System (INIS)

    Tuft, D.B.

    1979-04-01

    A method of computing laminar incompressible fluid-flow and heat transfer during the filling of a spherical annulus is presented. Transient fluid temperatures and heat flux rates in the spherical annulus are calculated for an insulated outer sphere and a constant temperature inner sphere with heated water filling the annulus from the bottom. To achieve a solution, laminar axially symmetric flow is assumed and the Marker-and-Cell (MAC) free surface computational method is applied to this problem in spherical coordinates. Changes in the standard MAC treatment are incorporated and special methods for handling the free surface are introduced. A variable mesh is used to improve resolution near the inner sphere where temperature and velocity gradients are steep and the governing equations are derived for variable fluid properties to allow an eddy viscosity turbulence model to be applied later. Calculations of velocity, temperature, and inner sphere heat flux in a spherical annulus of 139.7 mm inner radius, and 168.3 mm outer radius within an inlet tube diameter of 38.1 mm are presented

  6. Aortic annulus sizing using watershed transform and morphological approach for CT images

    Science.gov (United States)

    Mohammad, Norhasmira; Omar, Zaid; Sahrim, Mus'ab

    2018-02-01

    Aortic valve disease occurs due to calcification deposits on the area of leaflets within the human heart. It is progressive over time where it can affect the mechanism of the heart valve. To avoid the risk of surgery for vulnerable patients especially senior citizens, a new method has been introduced: Transcatheter Aortic Valve Implantation (TAVI), which places a synthetic catheter within the patient's valve. This entails a procedure of aortic annulus sizing, which requires manual measurement of the scanned images acquired from Computed Tomographic (CT) by experts. The step requires intensive efforts, though human error may still eventually lead to false measurement. In this research, image processing techniques are implemented onto cardiac CT images to achieve an automated and accurate measurement of the heart annulus. The image is first put through pre-processing for noise filtration and image enhancement. Then, a marker image is computed using the combination of opening and closing operations where the foreground image is marked as a feature while the background image is set to zero. Marker image is used to control the watershed transformation and also to prevent oversegmentation. This transformation has the advantage of fast computational and oversegmentation problems, which usually appear with the watershed transform can be solved with the introduction of marker image. Finally, the measurement of aortic annulus from the image data is obtained through morphological operations. Results affirm the approach's ability to achieve accurate annulus measurements compared to conventional techniques.

  7. analysis of flow in a concentric annulus using finite element method

    African Journals Online (AJOL)

    user

    Annular flow is a flow regime of two-phase gas-liquid. It is characterized by the presence of liquid fluid flowing on an annulus shaped channel. Annular flow is important in drilling and production in deviated and horizontal wells [2]. Concentric annular flows of fluids in pipes have had a number of engineering applications.

  8. Structural analysis and evaluation of the 241SY101 tank annulus heat-up

    International Nuclear Information System (INIS)

    Ziada, H.H.

    1994-01-01

    This document provides the structural analysis (static and thermal loads) of the 241SY101 tank to determine the maximum allowable temperature and rate of heating that could be applied to tank 241SY101 through annulus air heating without detrimental effects to the structural integrity of the concrete and steel liner of the tank

  9. Damping of a fluid-conveying pipe surrounded by a viscous annulus fluid

    Science.gov (United States)

    Kjolsing, Eric J.; Todd, Michael D.

    2017-04-01

    To further the development of a downhole vibration based energy harvester, this study explores how fluid velocity affects damping in a fluid-conveying pipe stemming from a viscous annulus fluid. A linearized equation of motion is formed which employs a hydrodynamic forcing function to model the annulus fluid. The system is solved in the frequency domain through the use of the spectral element method. The three independent variables investigated are the conveyed fluid velocity, the rotational stiffness of the boundary (using elastic springs), and the annulus fluid viscosity. It was found that, due to the hydrodynamic functions frequency-dependence, increasing the conveyed fluid velocity increases the systems damping ratio. It was also noted that stiffer systems saw the damping ratio increase at a slower rate when compared to flexible systems as the conveyed fluid velocity was increased. The results indicate that overestimating the stiffness of a system can lead to underestimated damping ratios and that this error is made worse if the produced fluid velocity or annulus fluid viscosity is underestimated. A numeric example was provided to graphically illustrate these errors. Approved for publication, LA-UR-15-28006.

  10. Caseous calcification of the mitral annulus: unmasking a master of disguise

    Directory of Open Access Journals (Sweden)

    Yale Tung-Chen

    2016-11-01

    Full Text Available Caseous calcification of the mitral annulus is an underdiagnosed disease, which can be associated with aging and cardiovascular risk factors: hypertension, diabetes, dyslipidemia or end-stage renal disease. This disease should be considered in the differential diagnosis in order to avoid unnecessary tests or even surgery.

  11. First bulk and surface results for the ATLAS ITk Strip stereo annulus sensors

    CERN Document Server

    Hunter, Robert Francis Holub; The ATLAS collaboration; Affolder, Tony; Bohm, Jan; Botte, James Michael; Ciungu, Bianca; Dette, Karola; Dolezal, Zdenek; Escobar, Carlos; Fadeyev, Vitaliy

    2018-01-01

    A novel microstrip sensor geometry, the stereo annulus, has been developed for use in the end-cap of the ATLAS experiment's strip tracker upgrade at the HL-LHC. Its first implementation is in the ATLAS12EC sensors a large-area, radiation-hard, single-sided, ac-coupled, \

  12. An annulus fibrosus closure device based on a biodegradable shape-memory polymer network

    NARCIS (Netherlands)

    Sharifi, Shahriar; van Kooten, Theo G.; Kranenburg, Hendrik-Jan C.; Meij, Bjorn P.; Behl, Marc; Lendlein, Andreas; Grijpma, Dirk W.

    2013-01-01

    Injuries to the intervertebral disc caused by degeneration or trauma often lead to tearing of the annulus fibrosus (AF) and extrusion of the nucleus pulposus (NP). This can compress nerves and cause lower back pain. In this study, the characteristics of poly(D,L-lactide-co-trimethylene carbonate)

  13. Numerical analysis of thermal behavior of a heat exchanger made of double-finned annulus

    International Nuclear Information System (INIS)

    Vaz Junior, M.; Colle, S.

    1986-01-01

    The present paper reports a boundary integral solution analysis of a countercurrent heat exchanger made of a double-finned annulus. The enhancement of the heat transfer surface is obtained by longitudinal straight finns which are placed on the intermediate surface. The Nusselt number is compared with data obtained from analytical solution available for limiting-cases. (author) [pt

  14. A rotating annulus driven by localized convective forcing: a new atmosphere-like experiment

    Science.gov (United States)

    Scolan, Hélène; Read, Peter L.

    2017-06-01

    We present an experimental study of flows in a cylindrical rotating annulus convectively forced by local heating in an annular ring at the bottom near the external wall and via a cooled circular disk near the axis at the top surface of the annulus. This new configuration is distinct from the classical thermally driven annulus analogue of the atmosphere circulation, in which thermal forcing is applied uniformly on the sidewalls, but with a similar aim to investigate the baroclinic instability of a rotating, stratified flow subjected to zonally symmetric forcing. Two vertically and horizontally displaced heat sources/sinks are arranged, so that in the absence of background rotation, statically unstable Rayleigh-Bénard convection would be induced above the source and beneath the sink, thereby relaxing strong constraints placed on background temperature gradients in previous experimental configurations based on the conventional rotating annulus. This better emulates local vigorous convection in the tropics and polar regions of the atmosphere while also allowing stably-stratified baroclinic motion in the central zone of the annulus, as in mid-latitude regions in the Earth's atmosphere. Regimes of flow are identified, depending mainly upon control parameters that in turn depend on rotation rate and the strength of differential heating. Several regimes exhibit baroclinically unstable flows which are qualitatively similar to those previously observed in the classical thermally driven annulus. However, in contrast to the classical configuration, they typically exhibit more spatio-temporal complexity. Thus, several regimes of flow demonstrate the equilibrated co-existence of, and interaction between, free convection and baroclinic wave modes. These new features were not previously observed in the classical annulus and validate the new setup as a tool for exploring fundamental atmosphere-like dynamics in a more realistic framework. Thermal structure in the fluid is

  15. Preclinical Evaluation of Bioabsorbable Polyglycolic Acid Spacer for Particle Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Akasaka, Hiroaki [Division of Radiation Oncology, Kobe University Graduate School of Medicine, Hyogo Japan (Japan); Sasaki, Ryohei, E-mail: rsasaki@med.kobe-u.ac.jp [Division of Radiation Oncology, Kobe University Graduate School of Medicine, Hyogo Japan (Japan); Miyawaki, Daisuke; Mukumoto, Naritoshi; Sulaiman, Nor Shazrina Binti [Division of Radiation Oncology, Kobe University Graduate School of Medicine, Hyogo Japan (Japan); Nagata, Masaaki [Division of Gastroenterology, Kobe University Graduate School of Medicine, Hyogo Japan (Japan); Yamada, Shigeru [Research Center Hospital, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba (Japan); Murakami, Masao [Radiation Oncology Center, Dokkyo Medical University, Tochigi (Japan); Demizu, Yusuke [Department of Radiology, Hyogo Ion Beam Medical Center, Hyogo (Japan); Fukumoto, Takumi [Division of Hepato-Biliary-Pancreatic Surgery, Kobe University Graduate School of Medicine, Hyogo Japan (Japan)

    2014-12-01

    Purpose: To evaluate the efficacy and safety of a polyglycolic acid (PGA) spacer through physical and animal experiments. Methods and Materials: The spacer was produced with surgical suture material made of PGA, forming a 3-dimensional nonwoven fabric. For evaluation or physical experiments, 150-MeV proton or 320-MeV carbon-ion beams were used to generate 60-mm width of spread-out Bragg peak. For animal experiments, the abdomens of C57BL/6 mice, with or without the inserted PGA spacers, were irradiated with 20 Gy of carbon-ion beam (290 MeV) using the spread-out Bragg peak. Body weight changes over time were scored, and radiation damage to the intestine was investigated using hematoxylin and eosin stain. Blood samples were also evaluated 24 days after the irradiation. Long-term thickness retention and safety were evaluated using crab-eating macaques. Results: No chemical or structural changes after 100 Gy of proton or carbon-ion irradiation were observed in the PGA spacer. Water equivalency of the PGA spacer was equal to the water thickness under wet condition. During 24 days' observation after 20 Gy of carbon-ion irradiation, the body weights of mice with the PGA spacer were relatively unchanged, whereas significant weight loss was observed in those mice without the PGA spacer (P<.05). In mice with the PGA spacer, villus and crypt structure were preserved after irradiation. No inflammatory reactions or liver or renal dysfunctions due to placement of the PGA spacer were observed. In the abdomen of crab-eating macaques, thickness of the PGA spacer was maintained 8 weeks after placement. Conclusions: The absorbable PGA spacer had water-equivalent, bio-compatible, and thickness-retaining properties. Although further evaluation is warranted in a clinical setting, the PGA spacer may be effective to stop proton or carbon-ion beams and to separate normal tissues from the radiation field.

  16. Grid spacers for use in a nuclear fuel assembly

    International Nuclear Information System (INIS)

    Kuwako, Akira.

    1987-01-01

    Purpose: To obtain spacers capable of reducing the pressure loss by enlarging coolant flow channels when the fuel temperature is high, while capable of reliably maintaining the fuel pins with no vibrations when the fuel temperature is low. Constitution: This invention concerns grid spacers for constituting fuel assemblies for use in water cooled reactors. Memory shape alloys are disposed at least a portion of a spacer element that takes such a shape as urging the pin when the fuel temperature is low, while enlarging the coolant flow channel to reduce the pressure loss when the fuel temperature is high. (Ikeda, J.)

  17. Preclinical Evaluation of Bioabsorbable Polyglycolic Acid Spacer for Particle Therapy

    International Nuclear Information System (INIS)

    Akasaka, Hiroaki; Sasaki, Ryohei; Miyawaki, Daisuke; Mukumoto, Naritoshi; Sulaiman, Nor Shazrina Binti; Nagata, Masaaki; Yamada, Shigeru; Murakami, Masao; Demizu, Yusuke; Fukumoto, Takumi

    2014-01-01

    Purpose: To evaluate the efficacy and safety of a polyglycolic acid (PGA) spacer through physical and animal experiments. Methods and Materials: The spacer was produced with surgical suture material made of PGA, forming a 3-dimensional nonwoven fabric. For evaluation or physical experiments, 150-MeV proton or 320-MeV carbon-ion beams were used to generate 60-mm width of spread-out Bragg peak. For animal experiments, the abdomens of C57BL/6 mice, with or without the inserted PGA spacers, were irradiated with 20 Gy of carbon-ion beam (290 MeV) using the spread-out Bragg peak. Body weight changes over time were scored, and radiation damage to the intestine was investigated using hematoxylin and eosin stain. Blood samples were also evaluated 24 days after the irradiation. Long-term thickness retention and safety were evaluated using crab-eating macaques. Results: No chemical or structural changes after 100 Gy of proton or carbon-ion irradiation were observed in the PGA spacer. Water equivalency of the PGA spacer was equal to the water thickness under wet condition. During 24 days' observation after 20 Gy of carbon-ion irradiation, the body weights of mice with the PGA spacer were relatively unchanged, whereas significant weight loss was observed in those mice without the PGA spacer (P<.05). In mice with the PGA spacer, villus and crypt structure were preserved after irradiation. No inflammatory reactions or liver or renal dysfunctions due to placement of the PGA spacer were observed. In the abdomen of crab-eating macaques, thickness of the PGA spacer was maintained 8 weeks after placement. Conclusions: The absorbable PGA spacer had water-equivalent, bio-compatible, and thickness-retaining properties. Although further evaluation is warranted in a clinical setting, the PGA spacer may be effective to stop proton or carbon-ion beams and to separate normal tissues from the radiation field

  18. Analysis of US patents on spacer grids

    International Nuclear Information System (INIS)

    Kim, Hyung Kyu; Song, Kee Nam; Yoon, Kyung Ho; Kang, Hong Seok; Kim, Hyung Kyu; Jeon, Tae Hyun; Oh, Dong Seok; In, Wang Ki; Bang, Jae Keun; Oh, Seung Eun; Seo, Jeong Min; Lee, Jin Seok; Park, Seong Keun

    1997-06-01

    The total of 137 US patents on spacer grids patented from 1968 through 1993 are analyzed and summarized. Database is constituted with designing the appropriate fields by which each patent can be identified. The fields consist of patent number, inventor, assignee, date of patent, title and major foci of the patent. The major foci are again classified by detailed subjects such as the fretting failure and fuel rod support-related, the strength-related, the fabrication-related as for mechanical subjects, while the cooling performance-related and the pressure drop-related as for thermal-hydraulic one. The 92% of the patents analyzed were issued form nuclear companies of USA, France and Germany. Among the patents dealing with mechanical subjects, the fretting failure and fuel rod support-related is more than the pressure drop-related among the patents of thermal-hydraulic subjects. The number of patents issued from Japan ranks just after Germany i.e., the 4th country. It is thought that much concern as well as investment should be increased in this field, the patent of nuclear components. (author). 2 tabs., 5 figs

  19. Surface plasmon resonance in electrodynamically coupled Au NPs monolayer/dielectric spacer/Al film nanostructure: tuning by variation of spacer thickness

    Science.gov (United States)

    Yeshchenko, Oleg A.; Kozachenko, Viktor V.; Liakhov, Yuriy F.; Tomchuk, Anastasiya V.; Haftel, Michael; Pinchuk, Anatoliy O.

    2017-10-01

    Effects of plasmonic coupling between metal nanoparticles and thin metal films separated by thin dielectric film-spacers have been studied by means of light extinction in three-layer planar Au NPs monolayer/dielectric (shellac) film/Al film nanostructure. The influence of coupling on the spectral characteristics of the Au NPs SPR extinction peak has been analyzed with spacer thickness, varied from 3 to 200 nm. The main observed features are a strong red shift (160 nm), and non-monotonical behavior of the magnitude and width of Au NPs SPR, as the spacer thickness decreased. The appearance of an intensive gap mode peak was observed at a spacer thickness smaller than approximately 30 nm, caused by the hybridization of the Au NPs SPR mode and gap mode in the presence of the Al film. Additionally, the appreciable enhancement (5.6 times) of light extinction by the Au NPs monolayer in the presence of Al film has been observed. A certain value of dielectric spacer thickness (70 nm) exists at which such enhancement is maximal.

  20. [Myxoma Originating from the Tricuspid Annulus Requiring Annular Reconstruction and Valve Replacement;Report of a Case].

    Science.gov (United States)

    Hattori, Masashi; Matsumura, Yu; Yamaki, Fumitaka

    2016-07-01

    A 66-year-old woman who had had coughing and worsening dyspnea for 3 weeks was admitted to our hospital. Echocardiography showed a solid round mass (72×49 mm in diameter) attached to the tricuspid septal annulus with a short stalk. A right atrial myxoma was suspected and operation was performed under cardiopulmonary bypass after heart failure symptoms subsided. The tumor was extirpated along with the tricuspid valve annulus. We performed reconstruction of the tricuspid annulus, tricuspid valve replacement with a bioprosthetic valve and pacemaker implantation. The histopathologic diagnosis was myxoma. The postoperative course was uneventful, and no recurrence has been noted for 1 year after surgery.

  1. Effect of the spacer group nature on the optical and electrical properties of confined poly( p-phenylene vinylene) derivatives

    Science.gov (United States)

    Benzarti-Ghédira, Maha; Zahou, Imen; Hrichi, Haikel; Jaballah, Nejmeddine; Ben Chaâbane, Rafik; Majdoub, Mustapha; Ben Ouada, Hafedh

    2015-09-01

    This study is an investigation about the effect of chemical modification on the morphological, optical and electrical properties of semiconducting organic thin films. Two confined poly( p-phenylene vinylene) (PPV)-type polymers containing different spacer groups were studied: P1 has an isopropylidene spacer group and P2 with hexafluoroisopropylidene spacer. The UV-Vis absorption and PL analysis showed a stronger π- π interaction in the P1 film; in P2, the π-stacking is limited by the introduction of a bulky trifluoromethyl (CF3) groups on the spacer units. The P2 exhibits a better film quality as illustrated by the atomic force microscopy. The HOMO and LUMO energy levels and electrochemical band gap of the polymers were determinate by the cyclic voltammetry. The electrical properties of ITO/PPV derivative/Al diodes were investigated by means of current-voltage and show a space-charge-limited current conduction mechanism with higher mobility in the P2 thin layer. The impedance spectra of the devices can be discussed in terms of an equivalent circuit model designed as a parallel resistance ( R p) and capacitance ( C p) network in series with a resistance.

  2. Surface-Tethered Iterative Carbohydrate Synthesis (STICS): A spacer study

    Science.gov (United States)

    Ganesh, N. Vijaya; Fujikawa, Kohki; Tan, Yih Horng; Nigudkar, Swati S.

    2013-01-01

    Comparative study of STICS using HPLC-assisted experimental set-up clearly demonstrated benefits of using longer spacer-anchoring systems. The use of mixed self-assembled monolayers helps to provide the required space for glycosylation reaction around the immobilized glycosyl acceptor. Both extension of the spacer length and using mixed self-assembled monolayers help to promote reaction and the beneficial effects may include moving the glycosyl acceptor further out into solution and providing additional conformational flexibility. It is possible that surface-immobilized glycosyl acceptors with a longer spacer (C8-O-C8)-lipoic acid have a higher tendency to mimic a solution-phase reaction environment than that of acceptors with shorter spacers. PMID:23822088

  3. Gravity Wave Emission by Spontaneous Imbalance of Baroclinic Waves in the Continuously Stratified Rotating Annulus

    Science.gov (United States)

    Borchert, Sebastian; Achatz, Ulrich; Rieper, Felix; Fruman, Mark

    2013-04-01

    We use a numerical model of the classic differentially heated rotating annulus experiment to study the spontaneous emission of gravity waves (GWs) from jet stream imbalances, which is a major source of these waves in the atmosphere for which no satisfactory parameterization exists. Atmospheric observations are the main tool for the testing and verification of theoretical concepts but have their limitations. Given their specific potential for yielding reproducible data and for studying process dependence on external system parameters, laboratory experiments are an invaluable complementary tool. Experiments with a rotating annulus exhibiting a jet modulated by large-scale waves due to baroclinic instability have already been used to study GWs: Williams et al (2008) observed spontaneously emitted interfacial GWs in a two-layer flow, and Jacoby et al (2011) detected GWs emitted from boundary-layer instabilities in a differentially heated rotating annulus. Employing a finite-volume code for the numerical simulation of a continuously stratified liquid in a differentially heated rotating annulus, we here investigate the GWs in a wide and shallow annulus with relatively large temperature difference between inner and outer cylinder walls. In this atmosphere-like regime where the Brunt-Vaisala frequency is larger than the inertial frequency, various analyses suggest a distinct gravity wave activity. To identify regions of GW emission we decompose the flow into the geostrophic and ageostrophic part through the inversion of the quasi-geostrophic potential vorticity (e.g. Verkley, 2009). The analysis of the geostrophic sources of the ageostrophic flow indicates that, in addition to boundary layer instabilities, spontaneous imbalance in the jet region acts as an important source mechanism. Jacoby, T. N. L., Read, P. L., Williams, P. D. and Young, R. M. B., 2011: Generation of inertia-gravity waves in the rotating thermal annulus by a localised boundary layer instability. Geophys

  4. Salvage of Infected Nasal Reconstruction with a Polymethyl Methacrylate Spacer

    Directory of Open Access Journals (Sweden)

    Pedro C. Cavadas, MD, PhD

    2017-07-01

    Full Text Available Summary:. Total nasal reconstruction is a challenging multistage procedure. Infections can destroy the cartilage framework and seriously compromise the result. The use of polymethyl methacrylate with antibiotics as a spacer has been described in the treatment of skeletal infections. Using this same principle, the use of a polymethyl methacrylate with antibiotics spacer for an infected nasal reconstruction is reported in a clinical case.

  5. Bioinformatics analyses of Shigella CRISPR structure and spacer classification.

    Science.gov (United States)

    Wang, Pengfei; Zhang, Bing; Duan, Guangcai; Wang, Yingfang; Hong, Lijuan; Wang, Linlin; Guo, Xiangjiao; Xi, Yuanlin; Yang, Haiyan

    2016-03-01

    Clustered regularly interspaced short palindromic repeats (CRISPR) are inheritable genetic elements of a variety of archaea and bacteria and indicative of the bacterial ecological adaptation, conferring acquired immunity against invading foreign nucleic acids. Shigella is an important pathogen for anthroponosis. This study aimed to analyze the features of Shigella CRISPR structure and classify the spacers through bioinformatics approach. Among 107 Shigella, 434 CRISPR structure loci were identified with two to seven loci in different strains. CRISPR-Q1, CRISPR-Q4 and CRISPR-Q5 were widely distributed in Shigella strains. Comparison of the first and last repeats of CRISPR1, CRISPR2 and CRISPR3 revealed several base variants and different stem-loop structures. A total of 259 cas genes were found among these 107 Shigella strains. The cas gene deletions were discovered in 88 strains. However, there is one strain that does not contain cas gene. Intact clusters of cas genes were found in 19 strains. From comprehensive analysis of sequence signature and BLAST and CRISPRTarget score, the 708 spacers were classified into three subtypes: Type I, Type II and Type III. Of them, Type I spacer referred to those linked with one gene segment, Type II spacer linked with two or more different gene segments, and Type III spacer undefined. This study examined the diversity of CRISPR/cas system in Shigella strains, demonstrated the main features of CRISPR structure and spacer classification, which provided critical information for elucidation of the mechanisms of spacer formation and exploration of the role the spacers play in the function of the CRISPR/cas system.

  6. The potential of standard and modified feed spacers for biofouling control

    KAUST Repository

    Araújo, Paula A.

    2012-06-01

    The impact of feed spacers on initial feed channel pressure (FCP) drop, FCP increase and biomass accumulation has been studied in membrane fouling simulators using feed spacers applied in commercially available nanofiltration and reverse osmosis spiral wound membrane modules. All spacers had a similar geometry.Our studies showed that biofouling was not prevented by (i) variation of spacer thickness, (ii) feed spacer orientation, (iii) feed spacer coating with silver, copper or gold and (iv) using a biostatic feed spacer. At constant feed flow, a lower FCP and FCP increase were observed for a thicker feed spacer. At constant linear flow velocity, roughly the same FCP development and biomass accumulation were found irrespective of the feed spacer thickness: hydrodynamics and substrate load were more important for development and impact of biofouling than the thickness of currently applied spacers. Use of biostatic and metal coated spacers were not effective for biofouling control. The same small reduction of biofouling rate was observed with copper and silver coated spacers as well as uncoated 45° rotated spacers.The studied modified spacers were not effective for biofouling prevention and control. The impact of biofouling on FCP increase was reduced significantly by a lower linear flow velocity, while spacer orientation and spacer thickness in membrane modules had a smaller but still significant effect. © 2012 Elsevier B.V.

  7. Dual reciprocity boundary element analysis for the laminar forced heat convection problem in concentric annulus

    International Nuclear Information System (INIS)

    Choi, Chang Yong

    1999-01-01

    This paper presents a study of the Dual Reciprocity Boundary Element Method (DRBEM) for the laminar heat convection problem in a concentric annulus with constant heat flux boundary condition. DRBEM is one of the most successful technique used to transform the domain integrals arising from the nonhomogeneous term of the poisson equation into equivalent boundary only integrals. This recently developed and highly efficient numerical method is tested for the solution accuracy of the fluid flow and heat transfer study in a concentric annulus. Since their exact solutions are available, DRBEM solutions are verified with different number of boundary element discretization and internal points. The results obtained in this study are discussed with the relative error percentage of velocity and temperature solutions, and potential applicability of the method for the more complicated heat convection problems with arbitrary duct geometries

  8. Exponential estimates of perturbations of rigid-plastic spreading-sink of an annulus

    Science.gov (United States)

    Georgievskii, D. V.; Tlyustangelov, G. S.

    2017-07-01

    The time evolution of the plane picture of small perturbations imposed on the radial spreading or sink of an annulus made of incompressible ideally rigid-plastic material obeying the Mises-Hencky plasticity criterion is studied. The adhesion conditions are posed on the extending (contracting) boundaries of the annulus in both the ground and perturbed processes. The method of integral relations, which is based on variational inequalities in the corresponding complex Hilbert space, is used to reduce the linearized problem in perturbations to a single relation for quadratic functionals, which permits deriving new exponential upper bounds for the growth or decay of kinematic perturbations. It is shown that the evolution of angular harmonics with distinct numbers is qualitatively distinct.

  9. Project Turnover Deliverables for the SY Farm Enraf Annulus Leak Detectors

    International Nuclear Information System (INIS)

    SCAIEF, C.C.

    2000-01-01

    This document identifies the deliverables that ensure the end user of the SY Farm Enraf Annulus Leak Detectors (ALD) has all the documentation and training required for operating and maintaining the new system. All deliverable items checked on the Acceptance For Beneficial Use (ABU) form have been completed and are available to the end user. This document was written as required by HNF-IP-0842, Volume IV section 3.12 Acceptance of Structures, Systems, and Components for Beneficial Use. This document applies to the deliverable documentation required to operate and maintain the SY Farm Enraf ALD System. Appendix A provides a copy of the ABU form as listed in the appendix of TWR-4092, Engineering Task Plan for the New SY Farm Annulus Leak Detectors. This document attests that all required deliverable items checked on the ABU have been completed and are available to the end user

  10. The acquisition radar’s detect annulus model of anti-submarine patrol aircraft

    Science.gov (United States)

    Wang, Jianguo; Yao, Keming; Wang, Xinwei; Men, Jinzhu

    2017-06-01

    Aiming at solving the problem of anti-submarine patrol aircraft(ASPA) detecting different sea-surface and aerial objects, based on the operation performance of acquisition radar, the paper puts forward the concept of detect annulus and establishes the corresponding model, and it gives the manner and method of ASPA detected objects. Through simulation and calculation, it discusses the different pattern of optical axis angle of depression and flight altitude from the width of detect annulus. The paper also provides the basis for the best optical axis angle of depression and flight altitude to meet the operational requirements. At last, the searching method of anti-submarine patrol aircraft using acquisition radar is put forward.

  11. Leak before break detection-annulus gas monitoring system evolution and operating experience at KGS

    International Nuclear Information System (INIS)

    Jain, D.D.; Sanathkumar, V.V.; Ramamurthy, K.; Nageswara Rao, G.

    2002-01-01

    Full text: Pressurised heavy water reactors (PHWR) at RAPS 1 and 2 and MAPS have provision for detection of pressure tube leak by indirect method. The reactor vessel (calandria) is housed in calandria vault (C/V) filled with air and C/V moisture element indicates the water leak from calandria tube or pressure tube. Further, detection of leak is a cumbersome process. From NAPS onwards, calandria is housed in C/V filled with water, annulus between calandria tube and pressure tube is filled with CO 2 and annulus gas monitoring system (AGMS) is provided by design for detection of any pressure tube leak. The design was improved and AGMS for Kaiga 1 and 2 and RAPS 3 and 4 is having re-circulation mode of operation. The design provides for monitoring dew point of annulus gas (CO 2 ) for indicating the leak and later to identify the pressure tube/calandria tube having leak. The paper deals with operating experience of AGMS at Kaiga generating station (KGS). During the commissioning and initial power operation at KGS, problems were encountered in re-circulation mode. These problems were high radiation field near AGMS piping, high temperature on blower body, blower bearing failure and system leaks. Design modifications were carried out for effective performance of the system for detecting leak before break

  12. SMART MONITORING AND DECISION MAKING FOR REGULATING ANNULUS BOTTOM HOLE PRESSURE WHILE DRILLING OIL WELLS

    Directory of Open Access Journals (Sweden)

    M. P. Vega

    Full Text Available Abstract Real time measurements and development of sensor technology are research issues associated with robustness and safety during oil well drilling operations, making feasible the diagnosis of problems and the development of a regulatory strategy. The major objective of this paper is to use an experimental plant and also field data, collected from a basin operation, offshore Brazil, for implementing smart monitoring and decision making, in order to assure drilling inside operational window, despite the commonly observed disturbances that produce fluctuations in the well annulus bottom hole pressure. Using real time measurements, the performance of a continuous automated drilling unit is analyzed under a scenario of varying levels of rate of penetration; aiming pressure set point tracking (inside the operational drilling window and also rejecting kick, a phenomenon that occurs when the annulus bottom hole pressure is inferior to the porous pressure, producing the migration of reservoir fluids into the annulus region. Finally, an empirical model was built, using real experimental data from offshore Brazil basins, enabling diagnosing and regulating a real drilling site by employing classic and advanced control strategies.

  13. Inertial wave mode excitation in a rotating annulus with partially librating boundaries

    Energy Technology Data Exchange (ETDEWEB)

    Borcia, Ion Dan; Harlander, U [Dept. Aerodynamics and Fluid Mechanics, Brandenburg University of Technology Cottbus-Senftenberg, Siemens-Halske-Ring 14, D-03046 Cottbus (Germany); Abouzar, Ghasemi V, E-mail: borciai@tu-cottbus.de [Dept. Environmental Meteorology, Brandenburg University of Technology Cottbus-Senftenberg, Burger Chaussee 2, D-03044 Cottbus (Germany)

    2014-08-01

    Inertial modes are excited in a fluid filled rotating annulus by modulating the rotation rate of the outer cylinder and the upper and lower lids. This forcing leads to inertial wave beams being emitted from the corner regions of the annulus due to periodic motions in the boundary layers. When the forcing frequency matches the eigenfrequency of the rotating annulus the beam pattern amplitude is increasing, the beams broaden and mode structures can be observed. The eigenmodes are compared with analytical solutions of the corresponding inviscid problem. In particular for the pressure field a good agreement can be found. However, shear layers related to the excited wave beams are present for all frequencies. This becomes obvious particularly in the experimental visualizations that are carried out by using Kalliroscope particles, highlighting relative motion in the fluid. Comparing the eigenfrequencies we find that relative to the analytical frequencies, the experimental and numerical ones show a small shift towards higher frequencies. This frequency shift is due to the reduction of the effective resonance volume that results from the existence of a Stokes boundary layer at the outer librating wall. Due to the symmetry of the forcing not all possible modes can be excited. It is shown that only symmetric modes with respect to the rotation axis exist. From a fundamental perspective, the study might help to better understand inertial mode excitation in librating planets and moons where inertial waves are emitted from critical points on the inner or outer spherical boundary. (paper)

  14. Interobserver variability of CT angiography for evaluation of aortic annulus dimensions prior to transcatheter aortic valve implantation (TAVI)

    Energy Technology Data Exchange (ETDEWEB)

    Schmidkonz, C., E-mail: christian.schmidkonz@gmail.com [Department of Internal Medicine 2 (Cardiology), University of Erlangen, Ulmenweg 18, D-91054 Erlangen (Germany); Marwan, M.; Klinghammer, L.; Mitschke, M.; Schuhbaeck, A.; Arnold, M. [Department of Internal Medicine 2 (Cardiology), University of Erlangen, Ulmenweg 18, D-91054 Erlangen (Germany); Lell, M. [Radiological Institute, University of Erlangen, Maximiliansplatz 1, D-91054 Erlangen (Germany); Achenbach, S.; Pflederer, T. [Department of Internal Medicine 2 (Cardiology), University of Erlangen, Ulmenweg 18, D-91054 Erlangen (Germany)

    2014-09-15

    Highlights: • Cardiac CT provides highly reproducible measurements of aortic annulus and root dimensions prior to TAVI. • The perimeter-derived aortic annulus diameter shows the lowest interobserver variability. • If all three CT sizing methods are considered and stated as a “consensus result”, mismatches in prosthesis size selection can be further reduced. - Abstract: Objective: Assessment of aortic annulus dimensions prior to transcatheter aortic valve implantation (TAVI) is crucial for accurate prosthesis sizing in order to avoid prosthesis–annulus-mismatch possibly resulting in complications like valve dislodgement, paravalvular regurgitation or annulus rupture. Contrast-enhanced multidetector computed tomography allows 3-dimensional assessment of aortic annulus dimensions. Only limited data exist about its interobserver variability. Methods: In 100 consecutive patients with symptomatic severe aortic stenosis (51 male, BMI 27 ± 5 kg/m{sup 2}, age 81 ± 7 years, heart rate 72 ± 15 bpm, Logistic Euroscore 31 ± 14%, STS-Score 7 ± 4%), pre-interventional aortic annulus assessment was performed by dual source computed tomography (collimation 2 × 128 × 0.6 mm, high pitch spiral data acquisition mode, 40–60 ml contrast agents, radiation dose 3.5 ± 0.9 mSv). The following aortic annulus characteristics were determined by three independent observers: aortic annulus maximum, minimum and mean diameters (D{sub max}, D{sub min}, D{sub mean}), eccentricity index (EI), effective aortic annulus diameter according to its circumference (D{sub circ}), effective aortic annulus diameter according to its area (D{sub area}), distance from the aortic annulus plane to the left (LCA) and right coronary artery (RCA) ostia, maximum (D{sub max}AR) and minimum aortic root diameter (D{sub min}AR), maximum (D{sub max}STJ) and minimum diameter of the sinotubular junction (D{sub min}STJ). Subsequently, interobserver variabilities were assessed. Results: Correlation between

  15. Impact of spacer thickness on biofouling in forward osmosis.

    Science.gov (United States)

    Valladares Linares, R; Bucs, Sz S; Li, Z; AbuGhdeeb, M; Amy, G; Vrouwenvelder, J S

    2014-06-15

    Forward osmosis (FO) indirect desalination systems integrate wastewater recovery with seawater desalination. Niche applications for FO systems have been reported recently, due to the demonstrated advantages compared to conventional high-pressure membrane processes such as nanofiltration (NF) and reverse osmosis (RO). Among them, wastewater recovery has been identified to be particularly suitable for practical applications. However, biofouling in FO membranes has rarely been studied in applications involving wastewater effluents. Feed spacers separating the membrane sheets in cross-flow systems play an important role in biofilm formation. The objective of this study was to determine the influence of feed spacer thickness (28, 31 and 46 mil) on biofouling development and membrane performance in a FO system, using identical cross-flow cells in parallel studies. Flux development, biomass accumulation, fouling localization and composition were determined and analyzed. For all spacer thicknesses, operated at the same feed flow and the same run time, the same amount of biomass was found, while the flux reduction decreased with thicker spacers. These observations are in good agreement with biofouling studies for RO systems, considering the key differences between FO and RO. Our findings contradict previous cross-flow studies on particulate/colloidal fouling, where higher cross-flow velocities improved system performance. Thicker spacers reduced the impact of biofouling on FO membrane flux. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Numerical analysis of the spacer grids' compression strength

    Energy Technology Data Exchange (ETDEWEB)

    Schettino, C.F.M.; Gouvea, J.P.; Medeiros, N., E-mail: carlosschettino@inb.gov.br, E-mail: jpg@metal.eeimvr.uff.br [Universidade Federal Fluminense (UFF), Volta Redonda, RJ (Brazil). Programa de Engenharia Metalurgica

    2013-07-01

    Among the components of the fuel assembly, the spacer grids play an important structural role during the energy generation process, mainly for their requirement to have enough structural strength to withstand lateral impact loads, due to fuel assembly shipping/handling and due to forces outcome from postulated accidents (earthquake and LOCA). This requirement ensures a proper geometry for cooling and for guide thimble straightness in the fuel assembly. In this way, the understanding of the macroscopic mechanical behavior of this component becomes essential even to any subsequent geometrical modifications to optimize the flue assemblies' structural behavior. In the present work, three-dimensional finite element models destined to provide consistent predictions of 16X16-type spacer grids lateral strength were proposed. Firstly, buckling tests based on results available in the literature were performed to establish a methodology for spacer grid finite element-based modeling. The, by considering a spacer grid interesting geometry and some possible variations associated to its fabrication, tolerance, the proposed numerical models were submitted to compression conditions to calculate the buckling force. Also, these models were validated for comparison with experimental buckling load results. Comparison of buckling predictions combined to observations of actual and simulated deformed spacer grids geometries permitted to verify the consistency and applicability of the proposed models. Thus, these numerical results show a good agreement between the and the experimental results. (author)

  17. A non-electrostatic spacer for aerosol delivery

    DEFF Research Database (Denmark)

    Bisgaard, H; Anhøj, J; Klug, B

    1995-01-01

    A pear shaped non-electrostatic spacer, composed of steel with a volume of 250 ml and equipped with a facemask containing integrated inlet and outlet valves for inspiration and expiration, was compared with three plastic spacers. The plastic spacers were primed with repeated puffs from a budesonide...... pressurised metered dose inhaler (p-MDI) to minimise the electrostatic charge on the plastic. The procedure prolonged the half life (t1/2) of the aerosol in the Nebuhaler from nine to 32 seconds. A normal cleaning procedure reduced the aerosol t1/2 back to baseline. The t1/2 of the aerosol in the metal spacer...... was 27 seconds and independent of the use of p-MDI. In vitro the maximum dose of budesonide from a p-MDI, expressed as a percentage of the nominal dose, was 56% from the non-electrostatic spacer, 61% from the Nebuhaler, 45% from the Babyhaler, and 30% from the AeroChamber. In 124 children, age 6 months...

  18. Zircaloy spacer grid for boiling light water reactors

    International Nuclear Information System (INIS)

    Borgiani, F.; Cali', G.P.; Cerretti, P.; Pazzo, P.

    1975-01-01

    The need to increase the neutronic efficiency of the new cores of BWR's, lead to study types of spacer-grids made of low neutronic absorption materials as zircaloy-4. The particular mechanical behaviour of this material suggested to design a spacer-grids such as to utilize only blanking, slotting and bending operations as plastic forming and to avoid therefore drawing effects. The optimization of the bending procedures lead to a final spacer-grids configuration equally stiff in all directions and planes. Only for the ''elastic constraints'' nichel alloy sheets were used to made easy the whole spacer design. The ''rigid constraints'', supporting the rods, have been obtained directly from the spacer structure. Calculations were performed to verify the mechanical strength of the main grid components. In this framework a computer code was developed to find the best elastic characteristic of the ''elastic constraints'' taking into account the machining tolerances. Some original methods to test the integral behaviour of the grid assembled as well as the procedures to be adopted for its best maintenance, are described

  19. Impact of spacer thickness on biofouling in forward osmosis

    KAUST Repository

    Valladares Linares, Rodrigo

    2014-06-01

    Forward osmosis (FO) indirect desalination systems integrate wastewater recovery with seawater desalination. Niche applications for FO systems have been reported recently, due to the demonstrated advantages compared to conventional high-pressure membrane processes such as nanofiltration (NF) and reverse osmosis (RO). Among them, wastewater recovery has been identified to be particularly suitable for practical applications. However, biofouling in FO membranes has rarely been studied in applications involving wastewater effluents. Feed spacers separating the membrane sheets in cross-flow systems play an important role in biofilm formation. The objective of this study was to determine the influence of feed spacer thickness (28, 31 and 46mil) on biofouling development and membrane performance in a FO system, using identical cross-flow cells in parallel studies. Flux development, biomass accumulation, fouling localization and composition were determined and analyzed. For all spacer thicknesses, operated at the same feed flow and the same run time, the same amount of biomass was found, while the flux reduction decreased with thicker spacers. These observations are in good agreement with biofouling studies for RO systems, considering the key differences between FO and RO. Our findings contradict previous cross-flow studies on particulate/colloidal fouling, where higher cross-flow velocities improved system performance. Thicker spacers reduced the impact of biofouling on FO membrane flux. © 2014 Elsevier Ltd.

  20. Analyses of the Collapse Behavior of a Spacer Grid

    International Nuclear Information System (INIS)

    Jang, Myung-Geun; Na, Geum Ju; Jag, Yeon-Hui; Kim, Hee Cheol; Kim, Jong-Bong; Kim, Jaeyoug

    2016-01-01

    In order to investigate the protection capability of a spacer grid assembly for impact load, a hammer impact test has been carried out. The crush strength is measured in the hammer impact test. Song et al. carried out the experiment and finite element analysis for the hammer impact test for various weld line depth. Park et al. designed the spacer grid shape to get required crush strength via finite element analysis. Song et al. also optimized the spacer grid shape to maximize the crush strength, and carried out the finite element analysis for the hammer impact test considering the weld properties. Kim et al. carried out finite element analysis for various guide tube hole shape and compared the crush shape and crush strength. In this study, the effect of shape defect on the crush behavior in the hammer impact test is investigated. The spacer grid cannot be exactly the square. Therefore a lateral displacement (imperfection) is imposed to square spacer grid and then hammer impact is carried out. The effect of the lateral imperfection on the crush strength is investigated. The effect of the shape defect on the crushing behavior in the hammer impact test is investigated by finite element analysis. It is shown that the collapse become severe as the lateral imperfection displacement increases, especially when the imperfection is greater than or equal to 0.7 mm

  1. CRISPR interference and priming varies with individual spacer sequences.

    Science.gov (United States)

    Xue, Chaoyou; Seetharam, Arun S; Musharova, Olga; Severinov, Konstantin; Brouns, Stan J J; Severin, Andrew J; Sashital, Dipali G

    2015-12-15

    CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR associated) systems allow bacteria to adapt to infection by acquiring 'spacer' sequences from invader DNA into genomic CRISPR loci. Cas proteins use RNAs derived from these loci to target cognate sequences for destruction through CRISPR interference. Mutations in the protospacer adjacent motif (PAM) and seed regions block interference but promote rapid 'primed' adaptation. Here, we use multiple spacer sequences to reexamine the PAM and seed sequence requirements for interference and priming in the Escherichia coli Type I-E CRISPR-Cas system. Surprisingly, CRISPR interference is far more tolerant of mutations in the seed and the PAM than previously reported, and this mutational tolerance, as well as priming activity, is highly dependent on spacer sequence. We identify a large number of functional PAMs that can promote interference, priming or both activities, depending on the associated spacer sequence. Functional PAMs are preferentially acquired during unprimed 'naïve' adaptation, leading to a rapid priming response following infection. Our results provide numerous insights into the importance of both spacer and target sequences for interference and priming, and reveal that priming is a major pathway for adaptation during initial infection. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  2. Biomechanical Analysis of an Expandable Lumbar Interbody Spacer.

    Science.gov (United States)

    Soriano-Baron, Hector; Newcomb, Anna G U S; Malhotra, Devika; Palma, Atilio E; Martinez-Del-Campo, Eduardo; Crawford, Neil R; Theodore, Nicholas; Kelly, Brian P; Kaibara, Taro

    2018-03-13

    Recently developed expandable interbody spacers are widely accepted in spinal surgery; however, the resulting biomechanical effects of their use have not yet been fully studied. We analyzed the biomechanical effects of an expandable polyetheretherketone interbody spacer inserted through a bilateral posterior approach with and without different modalities of posterior augmentation. Biomechanical nondestructive flexibility testing was performed in 7 human cadaveric lumbar (L2-L5) specimens followed by axial compressive loading. Each specimen was tested under 6 conditions: 1) intact, 2) bilateral L3-L4 cortical screw/rod (CSR) alone, 3) WaveD alone, 4) WaveD + CSR, 5) WaveD + bilateral L3-L4 pedicle screw/rod (PSR), and 6) WaveD + CSR/PSR, where CSR/PSR was a hybrid construct comprising bilateral cortical-level L3 and pedicle-level L4 screws interconnected by rods. The range of motion (ROM) with the interbody spacer alone decreased significantly compared with the intact condition during flexion-extension (P = 0.02) but not during lateral bending or axial rotation (P ≥ 0.19). The addition of CSR or PSR to the interbody spacer alone condition significantly decreased the ROM compared with the interbody spacer alone (P ≤ 0.002); and WaveD + CSR, WaveD + PSR, and WaveD + CSR/PSR (hybrid) (P ≥ 0.29) did not differ. The axial compressive stiffness (resistance to change in foraminal height during compressive loading) with the interbody spacer alone did not differ from the intact condition (P = 0.96), whereas WaveD + posterior instrumentation significantly increased compressive stiffness compared with the intact condition and the interbody spacer alone (P ≤ 0.001). The WaveD alone significantly reduced ROM during flexion-extension while maintaining the axial compressive stiffness. CSR, PSR, and CSR/PSR hybrid constructs were all effective in augmenting the expandable interbody spacer system and improving its stability. Copyright © 2018 Elsevier Inc. All

  3. ANNULUS CLOSURE TECHNOLOGY DEVELOPMENT INSPECTION/SALT DEPOSIT CLEANING MAGNETIC WALL CRAWLER

    International Nuclear Information System (INIS)

    Minichan, R; Russell Eibling, R; James Elder, J; Kevin Kane, K; Daniel Krementz, D; Rodney Vandekamp, R; Nicholas Vrettos, N

    2008-01-01

    The Liquid Waste Technology Development organization is investigating technologies to support closure of radioactive waste tanks at the Savannah River Site (SRS). Tank closure includes removal of the wastes that have propagated to the tank annulus. Although amounts and types of residual waste materials in the annuli of SRS tanks vary, simple salt deposits are predominant on tanks with known leak sites. This task focused on developing and demonstrating a technology to inspect and spot clean salt deposits from the outer primary tank wall located in the annulus of an SRS Type I tank. The Robotics, Remote and Specialty Equipment (RRSE) and Materials Science and Technology (MS and T) Sections of the Savannah River National Laboratory (SRNL) collaborated to modify and equip a Force Institute magnetic wall crawler with the tools necessary to demonstrate the inspection and spot cleaning in a mock-up of a Type I tank annulus. A remote control camera arm and cleaning head were developed, fabricated and mounted on the crawler. The crawler was then tested and demonstrated on a salt simulant also developed in this task. The demonstration showed that the camera is capable of being deployed in all specified locations and provided the views needed for the planned inspection. It also showed that the salt simulant readily dissolves with water. The crawler features two different techniques for delivering water to dissolve the salt deposits. Both water spay nozzles were able to dissolve the simulated salt, one is more controllable and the other delivers a larger water volume. The cleaning head also includes a rotary brush to mechanically remove the simulated salt nodules in the event insoluble material is encountered. The rotary brush proved to be effective in removing the salt nodules, although some fine tuning may be required to achieve the best results. This report describes the design process for developing technology to add features to a commercial wall crawler and the results of

  4. Comparison of aortic annulus diameter measurement between multi-detector computed tomography and echocardiography: a meta-analysis.

    Directory of Open Access Journals (Sweden)

    Ruifang Zhang

    Full Text Available BACKGROUND AND PURPOSE: Accurate measurement of aortic annulus diameter is crucial for choosing suitable prosthetic size for transcatheter aortic valve implantation (TAVI. Several imaging methods are available for the measurement, but significant variability between different modalities has been observed. The purpose of this study was to systematically compare the measurements of aortic annulus diameter between multi-detector computed tomography (MDCT, transthoracic echocardiography (TTE, and transesophegeal echocardiography (TEE. METHODS: PubMed and EMBASE databases between January 2000 and January 2012 were searched. We extracted data from eligible studies evaluating the aortic annulus diameter by MDCT and echocardiography (TTE, TEE, or both. We performed a random-effects meta-analysis to calculate the weighted mean differences of aortic annulus diameter measurement between MDCT, TTE, and TEE. RESULTS: A total of 10 eligible studies involving 581 subjects with aortic valve stenosis were included. Aortic annulus diameter measured on coronal view by MDCT (25.3±0.52 mm was respectively larger than that measured on sagittal view by MDCT (22.7±0.37 mm, TTE (22.6±0.28 mm, and TEE (23.1±0.32 mm. The weighted mean difference of aortic annulus diameter between coronal view by MDCT and TTE these two methods was 2.97 mm, followed by the weighted mean difference of 2.53 mm between coronal view and sagittal view by MDCT, and the mean difference of 1.74 mm between coronal view on MDCT and TEE (P<0.0001 for all. The weighted mean difference of aortic annulus diameter measurement between TEE and TTE was significant but somewhat small (0.45 mm, P = 0.007. CONCLUSION: Aortic annulus diameter measured on coronal view by MDCT was robustly and significantly larger than that obtained on sagittal view by MDCT, TTE, or TEE. Such variability of aortic annulus diameter measurement by different imaging modalities cannot be ignored when developing optimal

  5. Asymptotic behavior of positive solutions of a semilinear Dirichlet problem in the annulus

    Directory of Open Access Journals (Sweden)

    Safa Dridi

    2015-01-01

    Full Text Available In this paper, we establish existence and asymptotic behavior of a positive classical solution to the following semilinear boundary value problem: \\[-\\Delta u=q(xu^{\\sigma }\\;\\text{in}\\;\\Omega,\\quad u_{|\\partial\\Omega}=0.\\] Here \\(\\Omega\\ is an annulus in \\(\\mathbb{R}^{n}\\, \\(n\\geq 3\\, \\(\\sigma \\lt 1\\ and \\(q\\ is a positive function in \\(\\mathcal{C}_{loc}^{\\gamma }(\\Omega \\, \\(0\\lt\\gamma \\lt 1\\, satisfying some appropriate assumptions related to Karamata regular variation theory. Our arguments combine a method of sub- and supersolutions with Karamata regular variation theory.

  6. ANALYSIS OF CORROSION PRODUCT RETRIEVED FROM THE PRIMARY TANK WALL IN THE ANNULUS OF TANK 241-AY-102

    International Nuclear Information System (INIS)

    ANANTATMULA, R.P.

    2003-01-01

    Corrosion product from the annulus side of the double-shell tank 241-AY-102 primary wall was retrieved and analyzed. The analyses indicated that the tank wall was wetted with water leading to corrosion. The water source was quite likely the ingress of water from an external source and condensation of moisture during the long annulus ventilation system shutdowns. Corrosion of the primary tank wall in the annulus of double-shell tank (DST) 241-AY-102 was observed during the review of annulus videos of the tank in year 2001. This resulted in the issuance of an occurrence report, RP-CHG-TANKFARM-2001-0106. The occurrence report required collection and evaluation of the corrosion product to determine the cause of such corrosion. Therefore, a corrosion product sample was collected from the annulus side of the primary wall through Riser 80 in February 2003. The sample was scanned by Operational Health Physics and found to contain no radioactivity. The sample was then released and transmitted to ChemMet, Ltd , PC, for analyses. The present report discusses the types of analyses performed and the results of these analyses from ChemMet, Ltd , PC (Divine 2003) along with conclusions and recommendations. The letter report from ChemMet, Ltd, PC is attached

  7. Mitral annulus morphologic and functional analysis using real time tridimensional echocardiography in patients submitted to unsupported mitral valve repair.

    Science.gov (United States)

    Guedes, Marco Antônio Vieira; Pomerantzeff, Pablo Maria Alberto; Brandão, Carlos Manuel de Almeida; Vieira, Marcelo Luiz Campos; Tarasoutchi, Flávio; Spinola, Pablo da Cunha; Jatene, Fábio Biscegli

    2015-01-01

    Mitral valve repair is the treatment of choice to correct mitral insufficiency, although the literature related to mitral valve annulus behavior after mitral repair without use of prosthetic rings is scarce. To analyze mitral annulus morphology and function using real time tridimensional echocardiography in individuals submitted to mitral valve repair with Double Teflon technique. Fourteen patients with mitral valve insufficiency secondary to mixomatous degeneration that were submitted to mitral valve repair with the Double Teflon technique were included. Thirteen patients were in FC III/IV. Patients were evaluated in preoperative period, immediate postoperative period, 6 months and 1 year after mitral repair. Statistical analysis was made by repeated measures ANOVA test and was considered statistically significant P<0.05. There were no deaths, reoperation due to valve dysfunction, thromboembolism or endocarditis during the study. Posterior mitral annulus demonstrated a significant reduction in immediate postoperative period (P<0.001), remaining stable during the study, and presents a mean of reduction of 25.8% comparing with preoperative period. There was a significant reduction in anteroposterior and mediolateral diameters in the immediate postoperative period (P<0.001), although there was a significant increase in mediolateral diameter between immediate postoperative period and 1 year. There was no difference in mitral internal area variation over the cardiac cycle during the study. Segmentar annuloplasty reduced the posterior component of mitral annulus, which remained stable in a 1-year-period. The variation in mitral annulus area during cardiac cycle remained stable during the study.

  8. Shelf life of pie caps with biodegradable films as spacers

    Directory of Open Access Journals (Sweden)

    Daniela Verónica Escobar Gianni

    2013-01-01

    Full Text Available Commonly pie caps at market use polyethylene films as spacers between them. This paper studies the conventional spacers replacement with edible and biodegradable films made with whey protein isolate (WPI and potassium sorbate as a preservative. Besides facilitating the separation of pie caps, with this application is intended to increase their shelf life. The films made by the compression molding method were used as spacers in pie caps without preservative in their formula (A and with preservative (B and they were compared with conventional polyethylene spacers (C. During four months, monthly sensory, microbiological and physicochemical (humidity evaluations were done on the pie caps, together with humidity and solubility evaluations of the films. None of the samples showed microbiological or sensory deterioration. The sensory attributes showed no or slight difference in study time. Between samples the differences were minor: the best scores were for sample A in color, sample C in flavor, and samples B and C in texture and overall liking. The edible films have an interesting potential for this application, although studies in disguise the flavor of serum should be done.

  9. Deformation behavior of cell spring of an irradiated spacer grid

    International Nuclear Information System (INIS)

    Jin, Y. G.; Baek, S. J.; Ryu, W. S.; Kim, G. S.; Yoo, B. O.; Kim, D. S.; Ahn, S. B.; Chun, Y. B.; Choo, Y. S.

    2012-01-01

    Mechanical properties of a space grid of a fuel assembly are of great importance for fuel operation reliability in extended fuel burnup and duration of fuel life. The spacer grid with inner and outer straps has cell spring and dimples, which are in contact with the fuel rod. The spacer grids supporting the fuel rods absorb vibration impacts due to the reactor coolant flow and also grid spring force is decreasing under irradiation. This reduction of contact force might cause the grid to rod fretting wear. The fretting failure of the fuel rod is one of the significant issues recently in the nuclear industry from an economical as well as a safety concern. Thus, it is important to understand the characteristics of cell spring behavior for an irradiated spacer grid. In the present study, the stiffness test and dimensional measurement of cell springs were conducted to investigate the deformation behavior of cell springs of an irradiated spacer grid in a hot cell at IMEF (irradiated materials examination facility) of KAERI

  10. Novel spacers for mass transfer enhancement in membrane separations

    NARCIS (Netherlands)

    Li, F.; Meindersma, G.W.; de Haan, A.B.; Reith, T.

    2005-01-01

    The optimal flow pattern for mass transfer enhancement in spacer-filled channels is characterized by the coexistence of transversal and longitudinal vortices in the flow close to the channel walls and minimal cross-flow power consumption in the middle of the channel. The mass transfer enhancement of

  11. Multi-layer spacer geometries with improved mass transport

    NARCIS (Netherlands)

    Balster, J.H.; Punt, Ineke G.M.; Stamatialis, Dimitrios; Wessling, Matthias

    2006-01-01

    In electrodialysis desalination processes, it is desirable to operate at the highest practicable current density in order to get the maximum ion flux per unit membrane area. The operating current density is limited by concentration polarisation. In this work the development of optimal spacer

  12. CRISPR interference and priming varies with individual spacer sequences

    NARCIS (Netherlands)

    Xue, Chaoyou; Seetharam, Arun S.; Musharova, Olga; Severinov, Konstantin; Brouns, Stan J.J.; Severin, Andrew J.; Sashital, Dipali G.

    2015-01-01

    CRISPR-Cas (clustered regularly interspaced short palindromic repeats-CRISPR associated) systems allow bacteria to adapt to infection by acquiring 'spacer' sequences from invader DNA into genomic CRISPR loci. Cas proteins use RNAs derived from these loci to target cognate sequences for

  13. The internal transcribed spacer rDNA specific markers for ...

    African Journals Online (AJOL)

    ... schinifolium. These primers are useful to study the structure of Rutaceae family. Such identifications will be helpful for phylogenetic analysis in intraspecies population of the genus Zanthoxylum. Key words: Zanthoxylum piperitum, rDNA Int-sp markers, phylogenetic relationship, ribosomal DNA, internal transcribed spacer.

  14. The 'rare allele phenomenon' in a ribosomal spacer

    NARCIS (Netherlands)

    Schilthuizen, M.; Hoekstra, R.F.; Gittenberger, E.

    2001-01-01

    We describe the increased frequency of a particular length variant of the internal transcribed spacer 1 (ITS-1) of the ribosomal DNA in a hybrid zone of the land snail Albinaria hippolyti. The phenomenon that normally rare alleles or other markers can increase in frequency in the centre of hybrid

  15. Comparative phylogenetic analysis of intergenic spacers and small ...

    African Journals Online (AJOL)

    Two microsporidian isolates extracted from infected tasar silkworms (Antheraea mylitta) collected from forest area in Deoghar district, Jharkhand, India were subjected to PCR amplification using intergenic spacer (IGS) region and small subunit rRNA (SSU-rRNA) gene specific primers followed by cloning and sequencing.

  16. On the impact analysis of a PWR spacer grid

    International Nuclear Information System (INIS)

    Song, Kee Nam; Lee, S. H.

    2012-01-01

    A spacer grid, which is an interconnected array of slotted grid straps and is welded at the intersections to form an egg crate structure, is one of the most important structural components in a PWR fuel assembly. From a structural point of view, the spacer grid is required to have sufficient crush strength under lateral loads so that nuclear fuel rods are maintained in a cool able geometry, and that control rods can be inserted. The capacity of a spacer grid to resist lateral loads is usually characterized in terms of its crush strength, and it was reported that the lateral crush strength of the spacer grid is closely related with welding quality of the spacer grid. Microstructures in the weld zone, including a heat affected zone (HAZ), are different from that in a parent material. Consequently, the mechanical properties in the weld zone are different from those in the parent material to some extent. When a welded structure is loaded, the mechanical behavior of the welded structure might be different from the case of a structure with homogeneous mechanical properties. Nonetheless, mechanical properties in the welded structure have been neglected in many structural analyses of the spacer grid due to a lack of mechanical properties in the weld zone. When the weld zone is very narrow and the interfaces are not clear, it is difficult to take tensile test specimens in the weld zone. The reason for this is that the mechanical properties in the parent material are usually used in the structural analyses in the welded structure. As an aside, it has been recently determined that the ball indentation technique has the potential to be an excellent substitute for a standard tensile test, particularly in the case of small specimens or property gradient materials such as welds. In this study, to investigate the effect on the mechanical behavior of the spacer grid when using weld mechanical properties, strength analyses considering the weld mechanical properties recently obtained

  17. 3-D flow analyses for design of nuclear fuel spacer

    Energy Technology Data Exchange (ETDEWEB)

    Karouta, Z. [ABB Combustion Engineering, Windsor, CT (United States); GU, Chun-Yuan [ABB Corporate Research, Vaesteras (Sweden); Schoelin, B. [ABB Atom AB, Vaesteras (Sweden)

    1995-09-01

    The Computational Fluid Dynamics (CFD) code, CFDS-FLOW3D, was used to develop improved fuel designs for PWR cores. It was used primarily to understand the fluid dynamics of grid spacers, the mass transfer between subchannels caused by spacers and in the long term to develop two-phase models which enable prediction of critical heat flux in PWR fuel. A single subchannel of one grid span was modeled. In this model different spacer designs with mixing devices were analyzed. A special treatment of the boundary condition was developed making use of flow symmetry to model the mass transfer between different subchannels and minimize the size of the computational model. This reduced the computational model to a fraction of a subchannel using traditional periodic boundary conditions. The Navier-Stokes equation was solved for the liquid and the flow turbulence was modeled by k-{xi} turbulence model. The spacer and mixing device were treated as infinite thin surfaces in the model and a zero velocity condition and turbulent wall function were applied on each side of the thin surfaces. This approach simulated the swirl from the mixing devices well, but had the drawback of not predicting pressure drop accurately since the wake behind the plates and the acceleration effect of the spacers were ignored. CFDS-FLOW3D models with mixing devices were applied in the single-phase flow regime. Velocity profiles from the CFDS-FLOW3D models were compared to Laser Doppler Velocimeter measurements taken from the flow field downstream of spaces in a full scale, cold water test loop. The predicted axial and lateral velocity profiles were in good agreement with the measurements. The evaluation of the performance of different spacer devices was made by comparing the swirl ratio downstream of the grid spacers. It is planned to evaluate heat transfer coefficient downstream of the spaces, to implement two-phase flow models, and to model the superheated boundary layer on the surface of the fuel rod.

  18. Implementation of spacer therapy for acute asthma in children.

    LENUS (Irish Health Repository)

    Vandeleur, M

    2009-09-01

    The aim was to develop and implement an evidence based guideline for the treatment of acute asthma using a metered dose inhaler and spacer combination. Children admitted to Cork University Hospital Paediatric Department with acute asthma were identified during two identical 2 month seasonal periods before (2005) and after (2006) implementation of the new guidelines in September 2006. Pre-intervention and post-intervention audits by case note review were performed to determine the impact of and compliance with this evidence-based guideline emphasising patient assessment, spacer delivered bronchodilator and specific discharge criteria. Patients had similar characteristics during the two study periods. There was a raised threshold for admission after guideline implementation with 11\\/52 patients having mild exacerbations in 2006, compared to 21\\/36 in 2005. Duration of admission was less in the post-implementation group for equivalent exacerbation severity e.g. for moderate severity; 28 hours in 2005, 23 hours in 2006. Duration of bronchodilator therapy was shorter in 2006 and more likely to be given by spacer device earlier for equivalent levels of severity e.g. for moderate exacerbations, in 2006 the average length of salbutamol therapy was 18 hours with 12 hours by spacer device, in 2005 the average length of therapy was 25 hours with 3 hours by spacer. There was earlier initiation of oral corticosteroids; the average time to administration was 56 minutes in 2006 and 227 minutes in 2005. There was an improved documentation of asthma education in 2006 e.g. inhaler technique was reviewed in 37\\/52 in 2006, 21\\/35 in 2005 and better use of written action plans.

  19. First bulk and surface results for the ATLAS ITk stereo annulus sensors

    CERN Document Server

    Abidi, Syed Haider; The ATLAS collaboration; Bohm, Jan; Botte, James Michael; Ciungu, Bianca; Dette, Karola; Dolezal, Zdenek; Escobar, Carlos; Fadeyev, Vitaliy; Fernandez-Tejero, Xavi; Garcia-Argos, Carlos; Gillberg, Dag; Hara, Kazuhiko; Hunter, Robert Francis Holub

    2018-01-01

    A novel microstrip sensor geometry, the “stereo annulus”, has been developed for use in the end-cap of the ATLAS experiment’s strip tracker upgrade at the High-Luminosity Large Hadron Collider (HL- LHC). The radiation-hard, single-sided, ac-coupled, n + -in-p microstrip sensors are designed by the ITk Strip Sensor Collaboration and produced by Hamamatsu Photonics. The stereo annulus design has the potential to revolutionize the layout of end-cap microstrip trackers promising better tracking performance and more complete coverage than the contemporary configurations. These advantages are achieved by the union of equal length, radially oriented strips with a small stereo angle implemented directly into the sensor surface. The first-ever results for the stereo annulus geometry have been collected across several sites world- wide and are presented here. A number of full-size, unirradiated sensors were evaluated for their mechanical, bulk, and surface properties. The new device, the ATLAS12EC, is compared ag...

  20. Numerical study of evaporation in a vertical annulus heated at the inner wall

    Energy Technology Data Exchange (ETDEWEB)

    Ben Radhia, R.; Ben Jabrallah, S. [Laboratoire d' Energetique et des Transferts Thermique et Massique, Faculte des Sciences de Tunis, 1060 Tunis, Universite Tunis El Manar (Tunisia); Ben Jabrallah, S. [Faculte des sciences de Bizerte, 7021 Bizerte, Universite du 7 Novembre a Carthage (Tunisia); Corriou, J.P. [LRGP, Nancy Universite, CNRS-ENSIC-INPL, 1 rue Grandville, BP 20451, 54001 Nancy Cedex (France); Harmand, S. [Universite de Lille Nord de France, F-59000 Lille UVHC/TEMPO, F-59313 Valenciennes Cedex (France)

    2011-10-15

    Mixed convection during evaporation of a water falling film in a vertical concentric annulus was studied numerically. The water thin film falls on the inner tube and is subjected to a constant heat flux density, whereas the outer cylinder is assumed to be insulated and dry. An imposed air flow circulates within the gap between the two concentric tubes. The objective of this work is to understand the evaporation phenomenon in order to improve the average evaporated mass flux density and heat and mass transfer. Conservative equations governing the gas phase are solved numerically using the finite volume method. In the liquid phase, a method based on local heat and mass balances on each level is used. Thus, the following liquid film parameters, feed water mass flow, feed temperature and heat flux density, are taken into account. The obtained results are analyzed to emphasize and evaluate the influence of the previous operating parameters and the annulus curvature on the effective evaporation surface and on the mass flux density of evaporated water. (authors)

  1. Numerical and experimental investigation of bi-annulus heat exchanger for different alternative materials

    Science.gov (United States)

    Zeeshan, M.; Duggal, R.; Tated, M. K.; Singh, M.

    2018-02-01

    Heat exchangers are widely used in various energy-recovery applications. However, for specific applications where metallic tubes are subjected to various drawbacks i.e. cost, weight, corrosion etc. polymer materials are promising alternatives. In present study, various conventional as well as promising alternatives materials are chosen for investigation computationally. Experimentally, bi-annulus heat exchanger configuration is investigated for metallic materials. The simulations carried out conclude that the dimensionless temperature parameter for Cross-linked polypropylethylene (PEX) is greater than other polymers. It increases with increasing axial length of tube. The value for dimensionless temperature is higher for copper which is used as conventional tube material. Among different polymers highest temperature is observed for PEX followed by Low density polypropylene (LDPE), Polypropylene (PP) and Polyvinylidene fluoride (PVDF). For axial length up to 70mm approx. the temperature rises for PEX, LDPE is 28.3% and 26.4% respectively. However, temperature variation is same for PP and PVDF for same axial distance. This temperature variation is increased to 72.4%, 67.2%, 58.62% and 56.89% for PEX, LDPE, PP and PVDF respectively as axial distance variation reaches the end of pipe. The inner annulus temperature for PEX material at 10% length of tube is 28.3% of temperature achieved in copper tube which increases to 72.4% for full length of tube.

  2. Melting of a phase change material in a horizontal annulus with discrete heat sources

    Directory of Open Access Journals (Sweden)

    Mirzaei Hooshyar

    2015-01-01

    Full Text Available Phase change materials have found many industrial applications such as cooling of electronic devices and thermal energy storage. This paper investigates numerically the melting process of a phase change material in a two-dimensional horizontal annulus with different arrangements of two discrete heat sources. The sources are positioned on the inner cylinder of the annulus and assumed as constant-temperature boundary conditions. The remaining portion of the inner cylinder wall as well as the outer cylinder wall is considered to be insulated. The emphasis is mainly on the effects of the arrangement of the heat source pair on the fluid flow and heat transfer features. The governing equations are solved on a non-uniform O type mesh using a pressure-based finite volume method with an enthalpy porosity technique to trace the solid and liquid interface. The results are obtained at Ra=104 and presented in terms of streamlines, isotherms, melting phase front, liquid fraction and dimensionless heat flux. It is observed that, depending on the arrangement of heat sources, the liquid fraction increases both linearly and non-linearly with time but will slow down at the end of the melting process. It can also be concluded that proper arrangement of discrete heat sources has the great potential in improving the energy storage system. For instance, the arrangement C3 where the heat sources are located on the bottom part of the inner cylinder wall can expedite the melting process as compared to the other arrangements.

  3. Postpneumonectomy Compression of the Mitral Annulus: Rare Vascular Complication in Sportive Patient

    Directory of Open Access Journals (Sweden)

    David Debeaumont

    2016-01-01

    Full Text Available Numerous postpneumonectomy complications exist. We present a rare clinical case of postpneumonectomy exertional dyspnea revealing compression of the mitral annulus by the descending aorta. The patient was 42-year-old former smoker with pulmonary emphysema. He has been operated on, in 2012 (i.e., right pneumonectomy. Before the surgery, the patient was a recreational runner. However, after some months, it was difficult for the patient to resume running. Cardiopulmonary exercise testing indicated moderate exercise intolerance with important oxygen desaturation. More interestingly, a decrease of low oxygen pulse was noticed from the first ventilatory threshold with no electrical modification on the electrocardiogram. This decrease was indicative of a decline in stroke volume. The thoracic scan revealed a right pneumonectomy pocket with a liquid abnormal content. Moreover, the mediastinum had shifted toward the pneumonectomy space and the left lung was distended and emphysematous. Echocardiography revealed a major change in the mediastinal anatomy. The mitral annulus was observed to be compressed by the rear wall of the descending aorta. The diagnosis of postpneumonectomy syndrome or platypnea-orthodeoxia syndrome was ruled out in this patient. Mitral annular compression by the descending aorta is rare complication, which must be researched in patients with postpneumonectomy exertional dyspnea.

  4. Local interfacial structure of subcooled boiling flow in a heated annulus

    International Nuclear Information System (INIS)

    Lee, Tae-Ho; Kim, Seong-O; Yun, Byong-Jo; Park, Goon-Cherl; Hibiki, Takashi

    2008-01-01

    Local measurements of flow parameters were performed for vertical upward subcooled boiling flows in an internally heated annulus. The annulus channel consisted of an inner heater rod with a diameter of 19.0 mm and an outer round tube with an inner diameter of 37.5 mm, and the hydraulic equivalent diameter was 18.5 mm. The double-sensor conductivity probe method was used for measuring the local void fraction, interfacial area concentration, bubble Sauter mean diameter and gas velocity, whereas the miniature Pitot tube was used for measuring the local liquid velocity. A total of 32 data sets were acquired consisting of various combinations of heat flux, 88.1-350.9 kW/m 2 , mass flux, 469.7-1061.4kg(m 2 s) and inlet liquid temperature, 83.8-100.5degC. Six existing drift-flux models, six exiting correlations of the interfacial area concentration and bubble layer thickness model were evaluated using the data obtained in the experiment. (author)

  5. Columbia University flow instability experimental program: Volume 6. Single annulus tests, transient test program

    Energy Technology Data Exchange (ETDEWEB)

    Dougherty, T.; Maciuca, C.; McAssey, E.V. Jr.; Reddy, D.G.; Yang, B.W.

    1992-09-01

    The coolant in the Savannah River Site (SRS) production nuclear reactor assemblies is circulated as a subcooled liquid under normal operating conditions. This coolant is evenly distributed throughout multiple annular flow channels with a uniform pressure profile across each coolant flow channel. During the postulated Loss of Coolant Accident (LOCA), which is initiated by a hypothetical guillotine pipe break, the coolant flow through the reactor assemblies is significantly reduced. The flow reduction and accompanying power reduction (after shutdown is initiated) occur in the first 1 to 2 seconds of the LOCA. This portion of the LOCA is referred to as the Flow Instability phase. This report presents the experimental results for the transient portion of the single annulus test program. The test program was designed to investigate the onset of flow instability in an annular geometry similar to the MARK 22 reactor. The test program involved testing of both a ribless heater and a ribbed heater under steady state as well as transient conditions. The ribbed heater testing is currently underway and will be reported separately. The steady state portion of this test program with ribless heater was completed and reported in report No. CU-HTRF-T3A. The present report presents transient test results obtained from a ribless, uniform annulus test section. A total of thirty five transients were conducted with six cases in which flow excursion occurred. No unstable conditions resulted for tests in which the steady state Q{sub ratio} OFI limit was not exceeded.

  6. Numerical study of evaporation in a vertical annulus heated at the inner wall

    International Nuclear Information System (INIS)

    Ben Radhia, R.; Ben Jabrallah, S.; Ben Jabrallah, S.; Corriou, J.P.; Harmand, S.

    2011-01-01

    Mixed convection during evaporation of a water falling film in a vertical concentric annulus was studied numerically. The water thin film falls on the inner tube and is subjected to a constant heat flux density, whereas the outer cylinder is assumed to be insulated and dry. An imposed air flow circulates within the gap between the two concentric tubes. The objective of this work is to understand the evaporation phenomenon in order to improve the average evaporated mass flux density and heat and mass transfer. Conservative equations governing the gas phase are solved numerically using the finite volume method. In the liquid phase, a method based on local heat and mass balances on each level is used. Thus, the following liquid film parameters, feed water mass flow, feed temperature and heat flux density, are taken into account. The obtained results are analyzed to emphasize and evaluate the influence of the previous operating parameters and the annulus curvature on the effective evaporation surface and on the mass flux density of evaporated water. (authors)

  7. Dynamic changes in the ischemic mitral annulus: Implications for ring sizing

    Directory of Open Access Journals (Sweden)

    Khurram Owais

    2016-01-01

    Full Text Available Objectives: Contrary to the rest of the mitral annulus, inter-trigonal distance is known to be relatively less dynamic during the cardiac cycle. Therefore, intertrigonal distance is considered a suitable benchmark for annuloplasty ring sizing during mitral valve (MV surgery. The entire mitral annulus dilates and flattens in patients with ischemic mitral regurgitation (IMR. It is assumed that the fibrous trigone of the heart and the intertrigonal distance does not dilate. In this study, we sought to demonstrate the changes in mitral annular geometry in patients with IMR and specifically analyze the changes in intertrigonal distance during the cardiac cycle. Methods: Intraoperative three-dimensional transesophageal echocardiographic data obtained from 26 patients with normal MVs undergoing nonvalvular cardiac surgery and 36 patients with IMR undergoing valve repair were dynamically analyzed using Philips Qlab ® software. Results: Overall, regurgitant valves were larger in area and less dynamic than normal valves. Both normal and regurgitant groups displayed a significant change in annular area (AA during the cardiac cycle (P 0.05. Conclusions: Annular dimensions in regurgitant valves are dynamic and can be measured feasibly and accurately using echocardiography. The echocardiographically identified inter-trigonal distance does not change significantly during the cardiac cycle.

  8. Numerical Investigation of Compressor Non-Synchronous Vibration with Full Annulus Rotor-Stator Interaction

    Science.gov (United States)

    Espinal, Daniel

    The objective of this research is to investigate and confirm the periodicity of the Non-Synchronous Vibration (NSV) mechanism of a GE axial compressor with a full-annulus simulation. A second objective is to develop a high fidelity single-passage tool with time-accurate unsteady capabilities able to capture rotor-stator interactions and NSV excitation response. A high fidelity methodology for axial turbomachinery simulation is developed using the low diffusion shock-capturing Riemann solver with high order schemes, the Spalart-Allmaras turbulence closure model, the fully conservative unsteady sliding BC for rotor-stator interaction with extension to full-annulus and single-passage configurations, and the phase lag boundary conditions applied to rotor-stator interface and circumferential BC. A URANS solver is used and captures the NSV flow excitation frequency of 2439 Hz, which agrees reasonably well with the measured NSV frequency of 2600 Hz from strain gage test data. It is observed that the circumferentially traveling vortex formed in the vicinity of the rotor tip propagates at the speed of a non-engine order frequency and causes the NSV. The vortex travels along the suction surface of the blade and crosses the passage outlet near blade trailing edge. Such a vortex motion trajectory repeats in each blade passage and generates two low pressure regions due to the vortex core positions, one at the leading edge and one at the trailing edge, both are oscillating due to the vortex coming and leaving. These two low pressure regions create a pair of coupling forces that generates a torsion moment causing NSV. The full-annulus simulation shows that the circumferentially traveling vortex has fairly periodical behavior and is a full annulus structure. Also, frequencies below the NSV excitation frequency of 2439 Hz with large amplitudes in response to flow-separation related phenomena are present. This behavior is consistent with experimental measurements. For

  9. Electrical and electronic subsystems of a nuclear waste tank annulus inspection system

    Energy Technology Data Exchange (ETDEWEB)

    Evenson, R.J.

    1981-06-01

    The nuclear waste tank annulus inspection system is designed specifically for use at the Nuclear Regulatory Commission's Nuclear Fuel Services Facility at West Valley, New York. This system sends a television and photographic camera into the space between the walls of a double-shell nuclear waste tank to obtain images of the inner and outer walls at precisely known locations. The system is capable of inspecting a wall section 14 ft wide by 27 ft high. Due to the high temperature and radiation of the annulus environment, the operating life for the inspection device is uncertain, but is expected to be at least 100 h, with 1000 R/h at 82/sup 0/C. The film camera is shielded with 1/2 in. of lead to minimize radiation fogging of the film during a 25-min picture taking excursion. The operation of the inspection system is semiautomated with remote manual prepositioning of the camera, followed by a computer controlled wall scan. This apparatus is currently set up to take an array of contiguous pictures, but is adaptable to other modes of operation.

  10. Application of Regent mechanical valve in patients with small aortic annulus: 3-year follow-up

    Science.gov (United States)

    2012-01-01

    Background Aortic valve replacement (AVR) with a small aortic annulus is always challenging for the cardiac surgeon. In this study, we sought to evaluate the midterm performance of implantation with a 17-mm or 19-mm St. Jude Medical Regent (SJM Regent) mechanical valve in retrospective consecutive cohort of patients with small aortic annulus (diameter ≤ 19 mm). Methods From January 2008 to April 2011, 40 patients (31 female, mean age = 47.2 ± 5.8 years) with small aortic annulus (≤19 mm in diameter) underwent aortic valve replacement with a 17-mm or 19-mm St. Jude Medical Regent (SJM Regent) mechanical valve. Preoperative mean body surface area, New York Heart Association class, and mean aortic annulus were 1.61 ± 0.26 m2, 3.2 ± 0.4, and 18 ± 1.4 mm respectively. Patients were divided into two groups, according to the implantation of 17 mm SJM Regent mechanical valve (group 1, n = 18) or 19 mm SJM Regent valve (group 2, n = 22). All patients underwent echocardiography examination preoperatively and at one year post-operation. Results There were no early deaths in either group. Follow-up time averaged 36 ± 17.6 months. The mean postoperative New York Heart Association class was 1.3 ± 0.6 (p < 0.001). By echocardiography, in group 1, the left ventricular ejection fraction (LVEF), left ventricular fraction shortening (LVFS), and the indexed effective orifice area (EOAI) increased from 43.7% ± 11.6%, 27.3% ± 7.6%, and 0.70 ± 0.06 cm2/m2 to 69.8 ± 9.3%, 41.4 ± 8.3%, and 0.92 ± 0.10 cm2/m2 respectively (P < 0.05), while the left ventricular mass index (LVMI), and the aortic transvalvular pressure gradient decreased from 116.4 ± 25.4 g/m2, 46.1 ± 8.5 mmHg to 86.7 ± 18.2 g/m2 , 13.7 ± 5.2 mmHg respectively. In group 2, the LVEF, LVFS and EOAI increased from 45.9% ± 9.7%, 30.7% ± 8.0%, and 0.81 ± 0.09 cm2/m2 to 77.4%

  11. Application of Regent mechanical valve in patients with small aortic annulus: 3-year follow-up

    Directory of Open Access Journals (Sweden)

    Zhao Dong

    2012-09-01

    Full Text Available Abstract Background Aortic valve replacement (AVR with a small aortic annulus is always challenging for the cardiac surgeon. In this study, we sought to evaluate the midterm performance of implantation with a 17-mm or 19-mm St. Jude Medical Regent (SJM Regent mechanical valve in retrospective consecutive cohort of patients with small aortic annulus (diameter ≤ 19 mm. Methods From January 2008 to April 2011, 40 patients (31 female, mean age = 47.2 ± 5.8 years with small aortic annulus (≤19 mm in diameter underwent aortic valve replacement with a 17-mm or 19-mm St. Jude Medical Regent (SJM Regent mechanical valve. Preoperative mean body surface area, New York Heart Association class, and mean aortic annulus were 1.61 ± 0.26 m2, 3.2 ± 0.4, and 18 ± 1.4 mm respectively. Patients were divided into two groups, according to the implantation of 17 mm SJM Regent mechanical valve (group 1, n = 18 or 19 mm SJM Regent valve (group 2, n = 22. All patients underwent echocardiography examination preoperatively and at one year post-operation. Results There were no early deaths in either group. Follow-up time averaged 36 ± 17.6 months. The mean postoperative New York Heart Association class was 1.3 ± 0.6 (p 2/m2 to 69.8 ± 9.3%, 41.4 ± 8.3%, and 0.92 ± 0.10 cm2/m2 respectively (P 2, 46.1 ± 8.5 mmHg to 86.7 ± 18.2 g/m2 , 13.7 ± 5.2 mmHg respectively. In group 2, the LVEF, LVFS and EOAI increased from 45.9% ± 9.7%, 30.7% ± 8.0%, and 0.81 ± 0.09 cm2/m2 to 77.4% ± 9.7%, 44.5% ± 9.6%, and 1.27 ± 0.11 cm2/m2 respectively, while the LVMI, and the aortic transvalvular pressure gradient decreased from 118.3 ± 27.6 g/m2, 44.0 ± 6.7 mmHg to 80.1 ± 19.7 g/m2, 10.8 ± 4.1 mmHg as well. The prevalence of PPM was documented in 2 patients in Group 1. Conclusions Patients with small aortic annulus and body surface

  12. Optimization of non-woven spacers by CFD and validation by experiments

    NARCIS (Netherlands)

    Li, F.; Meindersma, G.W.; de Haan, A.B.; Reith, T.

    2002-01-01

    CFD simulations were used to determine mass transfer coefficients and power consumptions in channels filled with non-woven net spacers. The geometric parameters of a non-woven spacer were found to have a great influence on the performance of a spacer in terms of mass transfer enhancement and power

  13. Biofouling Control in Spiral-Wound Membrane Systems: Impact of Feed Spacer Modification and Biocides

    KAUST Repository

    Siddiqui, Amber

    2016-12-01

    High-quality drinking water can be produced with membrane-based filtration processes like reverse osmosis and nanofiltration. One of the major problems in these membrane systems is biofouling that reduces the membrane performance, increasing operational costs. Current biofouling control strategies such as pre-treatment, membrane modification, and chemical cleaning are not sufficient in all cases. Feed spacers are thin (0.8 mm), complex geometry meshes that separate membranes in a module. The main objective of this research was to evaluate whether feed spacer modification is a suitable strategy to control biofouling. Membrane fouling simulator studies with six feed spacers showed differences in biofouled spacer performance, concluding that (i) spacer geometry influences biofouling impact and (ii) biofouling studies are essential for evaluation of spacer biofouling impact. Computed tomography (CT) was found as a suitable technique to obtain three-dimensional (3D) measurements of spacers, enabling more representative mathematical modeling of hydraulic behavior of spacers in membrane systems. A strategy for developing, characterizing, and testing of spacers by numerical modeling, 3D printing of spacers and experimental membrane fouling simulator studies was developed. The combination of modeling and experimental testing of 3D printed spacers is a promising strategy to develop advanced spacers aiming to reduce the impact of biofilm formation on membrane performance and to improve the cleanability of spiral-wound membrane systems.

  14. Effect of plastic spacer handling on salbutamol lung deposition in asthmatic children

    DEFF Research Database (Denmark)

    Lipworth, Brian J; Lee, Daniel K C; Anhøj, Jacob

    2002-01-01

    AIMS: To study the effects of electrostatics in a plastic spacer on the lung deposition of salbutamol in asthmatic children. METHODS: Twenty-five children (5-12 years) with mild asthma were given salbutamol hydrofluoroalkane pressurized metered dose inhaler 400 micro g via a 750 ml plastic spacer.......14 fold (1.24, 3.69), or vs RinsedDelay 3.28 fold (2.13, 5.04). CONCLUSIONS: The relative lung dose of salbutamol from a plastic spacer may differ considerably depending on spacer handling suggesting that nonelectrostatic spacers may be the best way forward....

  15. Heat transfer in smooth and roughened rod bundles near spacer grids

    International Nuclear Information System (INIS)

    Marek, J.; Rehme, K.

    1975-03-01

    An experimental investigation was performed of the heat transfer in smooth and rough rod bundles near spacer grids. Detailed wall temperature distributions were measured which clearly demonstrated that even in rod bundles roughened by artificial roughnesses there are no hot spots near spacer grids. On the basis of the few experimental results from the literature and the new data, heat transfer correlations are proposed for smooth and rough surfaces near spacer grids. These correlations allow a prediction to be made in a good approximation of the heat transfer near spacer grids as a function of the flow contraction due to the spacer. (orig.) [de

  16. Response of an electrostatic probe for a right cylindrical spacer

    DEFF Research Database (Denmark)

    Rerup, T; Crichton, George C; McAllister, Iain Wilson

    1994-01-01

    During the last decade many experimental studies of surface charge phenomena have been undertaken employing right cylindrical spacers. Measurement of the surface charge was performed using small electrostatic field probes to scan across the dielectric surface. Charges are electrostatically induced...... on the sensor plate by the ambient surface charge, and hence as the probe is moved parallel to the surface the potential of the sensor plate changes. The probe sensor-plate potential is thus the parameter of interest as this parameter can be related in a quantitative manner to the surface charge density....... In the present study, the influence of the spacer geometry upon the λ-function is examined. This knowledge allows the response of the probe with reference to detection sensitivity and spatial selectivity to be considered. Such probe characteristics enable general conclusions to be reached about...

  17. An insulating grid spacer for large-area MICROMEGAS chambers

    International Nuclear Information System (INIS)

    Bernard, D.; Delagrange, H.; D'Enterria, D.G.; Guay, M.L.M. Le; Martinez, G.; Mora, M.J.; Pichot, P.; Roy, D.; Schutz, Y.; Gandi, A.; Oliveira, R. de

    2002-01-01

    We present a novel design for large-area gaseous detectors based on the MICROMEGAS technology. This technology incorporates an insulating grid, sandwiched between the micro-mesh and the anode-pad plane, which provides a uniform 200 μm amplification gap. The uniformity of the amplification gap thickness has been verified. The gain performances of the detector are presented and compared to the values obtained with detectors using cylindrical micro spacers. The new design presents several technical and financial advantages

  18. Bimetallic spacer means for a nuclear fuel assembly

    International Nuclear Information System (INIS)

    Anthony, A.J.

    1981-01-01

    A bimetallic spacer means designed to be cooperatively associated with a nuclear fuel assembly and operative to resist the occurrence of in-reactor bowing of the nuclear fuel assembly. The subject bimetallic spacer means in accord with one embodiment of the invention includes a member formed, at least principally, of Zircaloy to which are attached a plurality of stainless steel strips. The latter stainless steel strips are located on the external surface of the Zircaloy member and with the major axis of each of the plurality of stainless steel strips extending substantially perpendicular to the major axis of the Zircaloy member. In accord with another embodiment of the invention, the subject bimetallic spacer means includes a member formed at least principally of Zircaloy to which a plurality of stainless steel strips are attached so as to be positioned thereon externally thereof and with the major axis of each of the plurality of stainless steel strips extending substantially parallel to the major axis of the Zircaloy member. In accord with a further embodiment of the invention, the stainless steel strips are attached to preselected members, each embodying at least a cladding of Zircaloy, which are located in the rows of fuel rods that define the perimeter of the fuel matrix of the nuclear fuel assembly. In each of the embodiments, the stainless steel strips during power production expand outwardly to a greater extent than do the members to which the stainless steel strips are attached, thereby forming stiff springs which abut against like bimetallic spacer means with which the other nuclear fuel assemblies are provided in a given nuclear reactor core to thus prevent the occurrence of in-reactor bowing of the nuclear fuel assemblies. Namely, the stainless steel strips expand laterally relative to the fuel assembly and thereby occupy the space adjacent to the external surface of the fuel assembly

  19. Impact of feed spacer and membrane modification by hydrophilic, bactericidal and biocidal coating on biofouling control

    KAUST Repository

    Araújo, Paula A.

    2012-06-01

    The influence of polydopamine- and polydopamine-. graft-poly(ethylene glycol)-coated feed spacers and membranes, copper-coated feed spacers, and commercially-available biostatic feed spacers on biofouling has been studied in membrane fouling simulators. Feed spacers and membranes applied in practical membrane filtration systems were used; biofouling development was monitored by feed channel pressure drop increase and biomass accumulation. Polydopamine and polydopamine-. g-PEG are hydrophilic surface modification agents expected to resist protein and bacterial adhesion, while copper feed spacer coatings and biocides infused in feed spacers are expected to restrict biological growth. Our studies showed that polydopamine and polydopamine-. g-PEG coatings on feed spacers and membranes, copper coatings on feed spacers, and a commercial biostatic feed spacer did not have a significant impact on feed channel pressure drop increase and biofilm accumulation as measured by ATP and TOC content. The studied spacer and membrane modifications were not effective for biofouling control; it is doubtful that feed spacer and membrane modification, in general, may be effective for biofouling control regardless of the type of applied coating. © 2012 Elsevier B.V.

  20. Membrane-spacer assembly for flow-electrode capacitive deionization

    Science.gov (United States)

    Lee, Ki Sook; Cho, Younghyun; Choo, Ko Yeon; Yang, SeungCheol; Han, Moon Hee; Kim, Dong Kook

    2018-03-01

    Flow-electrode capacitive deionization (FCDI) is a desalination process designed to overcome the limited desalination capacity of conventional CDI systems due to their fixed electrodes. Such a FCDI cell system is comprised of a current collector, freestanding ion-exchange membrane (IEM), gasket, and spacer for flowing saline water. To simplify the cell system, in this study we combined the membrane and spacer into a single unit, by coating the IEM on a porous ceramic structure that acts as the spacer. The combination of membrane with the porous structure avoids the use of costly freestanding IEM. Furthermore, the FCDI system can be readily scaled up by simply inserting the IEM-coated porous structures in between the channels for flow electrodes. However, coating the IEM on such porous ceramic structures can cause a sudden drop in the treatment capacity, if the coated IEM penetrates the ceramic pores and prevents these pores from acting as saline flow channels. To address this issue, we blocked the larger microscale pores on the outer surface with SiO2 and polymeric multilayers. Thus, the IEM is coated only onto the top surface of the porous structure, while the internal pores remain empty to function as water channels.

  1. Increased antibiotic release and equivalent biomechanics of a spacer cement without hard radio contrast agents.

    Science.gov (United States)

    Bitsch, R G; Kretzer, J P; Vogt, S; Büchner, H; Thomsen, M N; Lehner, B

    2015-10-01

    We compared a novel calcium carbonate spacer cement (Copal® spacem) to well-established bone cements. Electron microscopic structure and elution properties of the antibiotics ofloxacin, vancomycin, clindamycin, and gentamicin were examined. A knee wear simulator model for articulating cement spacers was established. Mechanical tests for bending strength, flexural modulus, and compressive and fatigue strength were performed. The electron microscopic analysis showed a microporous structure of the spacer cement, and this promoted a significantly higher and longer antibiotic elution. All spacer cement specimens released the antibiotics for a period of up to 50days with the exception of the vancomycin loading. The spacer cement showed significantly less wear scars and fulfilled the ISO 5833 requirements. The newly developed spacer cement is a hydrophilic antibiotic carrier with an increased release. Cement without hard radio contrast agents can improve tribological behaviour of spacers, and this may reduce reactive wear particles and abrasive bone defects. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Human adipose stem cells in chondrogenic differentiation medium without growth factors differentiate towards annulus fibrosus phenotype in vitro

    NARCIS (Netherlands)

    Gebraad, Arjen; Miettinen, S.; Grijpma, Dirk W.; Haimi, Suvi

    2013-01-01

    Intervertebral disc degeneration is the main cause of chronic back pain. Disc degeneration mainly leads to tearing of annulus fibrosus (AF), which is with current methods difficult to restore and impossible to regenerate. Stem cell technology offers a potential technique to repair the ruptured AF by

  3. Analysis of optical vortices with suppressed sidelobes using modified Bessel-like function and trapezoid annulus modulation structures.

    Science.gov (United States)

    Guo, Jian; Wei, Zhongchao; Liu, Yuebo; Huang, Aili

    2015-02-01

    Two amplitude modulation methods, including modified Bessel-like function modulation structure and trapezoid annulus structure, for suppressing sidelobes of optical vortices are studied. In the former approach, we propose that the order of the Bessel-like function can be an additional parameter to modulate diffraction patterns of optical vortices motivated by the idea of conventional annulus structures. Furthermore, new Bessel-like modulation functions are introduced to solve the problem of low diffraction efficiency of the original one. Trapezoid annulus structure is proposed as a compromise structure between the modified Bessel-like modulation structure and the conventional annulus one, and has advantages of both. It is demonstrated that these two approaches can achieve high-quality optical vortices with suppressed sidelobes effectively, and the relative structures behave as more flexible and applicable structures for producing optical vortices with large coverage of topological charges, which suggests great potential in simplifying the structure designing procedure. These reliable and generalized structures for generating high-quality optical vortices will help to promote the development of future optical communication and optical manipulation significantly.

  4. Burn-out, Circumferential Film Flow Distribution and Pressure Drop for an Eccentric Annulus with Heated Rod

    DEFF Research Database (Denmark)

    Andersen, P. S.; Jensen, A.; Mannov, G.

    1974-01-01

    Measurements of (1) burn-out, (2) circumferential film flow distribution, and (3) pressure drop in a 17 × 27.2 × 3500 mm concentric and eccentric annulus geometry are presented. The eccentric displacement was varied between 0 and 3 mm. The working fluid was water. Burn-out curves at 70 bar...... flow variation on burn-out is discussed....

  5. CANDU pressure tube leak detection by annulus gas dew point measurement. A critical review

    Energy Technology Data Exchange (ETDEWEB)

    Greening, F.R. [CTS-NA, Tiverton, ON (Canada)

    2017-03-15

    In the event of a pressure tube leak from a small through-wall crack during CANDU reactor operations, there is a regulatory requirement - referred to as Leak Before Break (LBB) - for the licensee to demonstrate that there will be sufficient time for the leak to be detected and the reactor shut down before the crack grows to the critical size for fast-uncontrolled rupture. In all currently operating CANDU reactors, worldwide, this LBB requirement is met via continuous dew point measurements of the CO{sub 2} gas circulating in the reactor's Annulus Gas System (AGS). In this paper the historical development and current status of this leak detection capability is reviewed and the use of moisture injection tests as a verification procedure is critiqued. It is concluded that these tests do not represent AGS conditions that are to be expected in the event of a real pressure tube leak.

  6. Numerical simulation of solidification in a horizontal cylindrical annulus charged with an aqueous salt solution

    Science.gov (United States)

    Neilson, D. G.; Incropera, F. D.; Bennon, W. D.

    1990-01-01

    A computational study of solidification of a binary Na2CO3 solution in a horizontal cylindrical annulus is performed using a continuum formulation with a control-volume based, finite-difference scheme. The initial conditions were selected to facilitate the study of counter thermal and solutal convection, accompanied by extensive mushy region growth. Numerical results are compared with experimental data with mixed success. Qualitative agreement is obtained for the overall solidification process and associated physical phenomena. However, the plume thickness calculated for the solutally-driven convective upflow is substantially smaller than the observed value. Evolution of double-diffusive layers is predicted, but over a time scale much smaller than that observed experimentally. Good agreement is obtained between predicted and measured results for solid growth, but the mushy region thickness is significantly overpredicted.

  7. Unsteady three-dimensional behavior of natural convection in horizontal annulus

    International Nuclear Information System (INIS)

    Ohya, Toshizo; Miki, Yasutomi; Morita, Kouji; Fukuda, Kenji; Hasegawa, Shu

    1988-01-01

    An numerical analysis has been performed on unsteady three-dimensional natural convection in a concentric horizontal annulus filled with air. The explicit leap-frog scheme is used for integrating three-dimensional time-dependent equations and the fast Fourier transform (FFT) for solving the Poisson equations for pressure. An oscillatory flow is found to occur at high Rayleigh numbers, which agree qualitatively with the experimental observation made by Bishop et al. An experiment is also conducted to measure temperature fluctuations; a comparison between periods of fluctuations obtained numerically and experimentally shows a good agreement. Numerical calculations yield various statistical parameters of turbulence at higher Rayleigh numbers, which wait experimental verificaions, however. (author)

  8. Critical heat-flux experiments under low-flow conditions in a vertical annulus

    International Nuclear Information System (INIS)

    Mishima, K.; Ishii, M.

    1982-03-01

    An experimental study was performed on critical heat flux (CHF) at low flow conditions for low pressure steam-water upward flow in an annulus. The test section was transparent, therefore, visual observations of dryout as well as various instrumentations were made. The data indicated that a premature CHF occurred due to flow regime transition from churn-turbulent to annular flow. It is shown that the critical heat flux observed in the experiment is essentially similar to a flooding-limited burnout and the critical heat flux can be well reproduced by a nondimensional correlation derived from the previously obtained criterion for flow regime transition. The observed CHF values are much smaller than the standard high quality CHF criteria at low flow, corresponding to the annular flow film dryout. This result is very significant, because the coolability of a heater surface at low flow rates can be drastically reduced by the occurrence of this mode of CHF

  9. Experimental study on convective boiling heat transfer in narrow-gap annulus tubes

    International Nuclear Information System (INIS)

    Li Bin; Zhao Jianfu; Tang Zemei; Hu Wenrui; Zhou Fangde

    2004-01-01

    Since convective boiling or highly subcooled single-phase forced convection in micro-channels is an effective cooling mechanism with a wide range of applications, more experimental and theoretical studies are required to explain and verify the forced convection heat transfer phenomenon in narrow channels. In this experimental study, authors model the convective boiling behavior of water with low latent heat substance Freon 113 (R-113), with the purpose of saving power consumption and visualizing experiments. Both heat transfer and pressure drop characteristics were measured in subcooled and saturated concentric narrow gap forced convection boiling. Data were obtained to qualitatively identify the effects of gap size, pressure, flow rate and wall superheat on boiling regimes and the transition between various regimes. Some significant differences from unconfined forced convection boiling were found, and also, the flow patterns in narrow vertical annulus tubes have been studied quantitatively. (authors)

  10. Experimental study on natural-convection boiling burnout in an annulus

    International Nuclear Information System (INIS)

    Mishima, K.; Ishii, M.

    1982-01-01

    An experimental study was performed on burnout heat flux at low flow rates for low-pressure steam-water upward flow in an annulus. The data indicated that a premature burnout occurred due to flow-regime transition from churn-turbulent to annular flow. It is shown that the burnout observed in the experiment is essentially a flooding-limited burnout and the burnout heat flux can be well reproduced by a nondimensional correlation derived from the previously obtained criterion for flow-regime transition. It is also shown that the conventional correlations for burnout heat flux at low mass velocities agree well with the data on circulation and entrainment-limited burnout

  11. Limits on Annulus Air Outages in Types 1, 2, and 3 Waste Tanks

    International Nuclear Information System (INIS)

    Wiersma, B.J.; Sindelar, R. L.

    1995-01-01

    An evaluation was performed on the impact of abnormal air flow conditions on the structural integrity of Types 1, 2, and 3 waste tanks. Warm, dry air in the annular space is necessary to preclude low temperature embrittlement and corrosive conditions for the carbon steel materials. For Type 1 and 2 tanks the annulus air system should be repaired within a month to minimize the potential for low temperature embrittlement and corrosive conditions, for Tanks 29-34, which are Type 3 tanks, it is recommended that the system be repaired within two months to minimize the potential for low temperature embrittlement. For all other Type 3 tanks repair of the system within six months is adequate to minimize general corrosion

  12. Independent tuning of double plasmonic waves in a free-standing graphene-spacer-grating-spacer-graphene hybrid slab.

    Science.gov (United States)

    Chen, Ying; Yao, Jin; Song, Zhengyong; Ye, Longfang; Cai, Guoxiong; Liu, Qing Huo

    2016-07-25

    The independent excitation and tuning of double plasmonic waves are realized in a free-standing graphene-spacer-grating-spacer-graphene (GSGSG) hybrid slab, which consists of two graphene field effect transistors placed back-to-back to each other. Resulted from the high transparency and the tight confinement of surface plasmonic mode for the graphene, double plasmonic waves can be independently excited by guided-mode resonances (GMRs). Theoretical and numerical investigations are performed in the mid-infrared band. Furthermore, the tuning of individual GMR resonant wavelengths with respect to the system parameters is studied. The results provide opportunities to engineer the proposed hybrid slab for wavelength selective and multiplexing applications.

  13. Development and characterization of 3D-printed feed spacers for spiral wound membrane systems

    KAUST Repository

    Siddiqui, Amber

    2016-01-02

    Feed spacers are important for the impact of biofouling on the performance of spiral-wound reverse osmosis (RO) and nanofiltration (NF) membrane systems. The objective of this study was to propose a strategy for developing, characterizing, and testing of feed spacers by numerical modeling, three-dimensional (3D) printing of feed spacers and experimental membrane fouling simulator (MFS) studies. The results of numerical modeling on the hydraulic behavior of various feed spacer geometries suggested that the impact of spacers on hydraulics and biofouling can be improved. A good agreement was found for the modeled and measured relationship between linear flow velocity and pressure drop for feed spacers with the same geometry, indicating that modeling can serve as first step in spacer characterization. An experimental comparison study of a feed spacer currently applied in practice and a 3D printed feed spacer with the same geometry showed (i) similar hydraulic behavior, (ii) similar pressure drop development with time and (iii) similar biomass accumulation during MFS biofouling studies, indicating that 3D printing technology is an alternative strategy for development of thin feed spacers with a complex geometry. Based on the numerical modeling results, a modified feed spacer with low pressure drop was selected for 3D printing. The comparison study of the feed spacer from practice and the modified geometry 3D printed feed spacer established that the 3D printed spacer had (i) a lower pressure drop during hydraulic testing, (ii) a lower pressure drop increase in time with the same accumulated biomass amount, indicating that modifying feed spacer geometries can reduce the impact of accumulated biomass on membrane performance. The combination of numerical modeling of feed spacers and experimental testing of 3D printed feed spacers is a promising strategy (rapid, low cost and representative) to develop advanced feed spacers aiming to reduce the impact of biofilm formation on

  14. Association of mitral annulus calcification, aortic valve calcification with carotid intima media thickness

    Directory of Open Access Journals (Sweden)

    Scuteri Angelo

    2004-10-01

    Full Text Available Abstract Background Mitral annular calcification (MAC and aortic annular calcification (AVC may represent a manifestation of generalized atherosclerosis in the elederly. Alterations in vascular structure, as indexed by the intima media thickness (IMT, are also recognized as independent predictors of adverse cardiovascular outcomes. Aim To examine the relationship between the degree of calcification at mitral and/or aortic valve annulus and large artery structure (thickness. Methods We evaluated 102 consecutive patients who underwent transthoracic echocardiography and carotid artery echoDoppler for various indications; variables measured were: systemic blood pressure (BP, pulse pressure (PP=SBP-DBP, body mass index (BMI, fasting glucose, total, HDL, LDL chlolesterol, triglycerides, cIMT. The patients were divided according to a grading of valvular/annular lesions independent scores based on acoustic densitometry: 1 = annular/valvular sclerosis/calcification absence; 2 = annular/valvular sclerosis; 3 = annular calcification; 4 = annular-valvular calcification; 5 = valvular calcification with no recognition of the leaflets. Results Patient score was the highest observed for either valvular/annulus. Mean cIMT increased linearly with increasing valvular calcification score, ranging from 3.9 ± 0.48 mm in controls to 12.9 ± 1.8 mm in those subjects scored 5 (p 0.0001. Conclusion MAC and AVC score can identify subgroups of patients with different cIMT values which indicate different incidence and prevalence of systemic artery diseases. This data may confirm MAC-AVC as a useful important diagnostic parameter of systemic atherosclerotic disease.

  15. Staging Mobilities / Designing Mobilities

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    2015-01-01

    In recent years, urban research has taken a ‘mobilities turn’. There has been a developing realisation that mobilities do not ‘just happen.’ Mobilities are carefully and meticulously designed, planned and staged (from above). However, they are equally importantly acted out, performed and lived...... asks: what are the physical, social, technical, and cultural conditions to the staging of contemporary urban mobilities? The theoretical framing in the Staging mobilities book is applied to four in-depth cases in the accompanying volume Designing mobilities.This book explore how places, sites...

  16. Mobile marketing for mobile games

    OpenAIRE

    Vu, Giang

    2016-01-01

    Highly developed mobile technology and devices enable the rise of mobile game industry and mobile marketing. Hence mobile marketing for mobile game is an essential key for a mobile game success. Even though there are many articles on marketing for mobile games, there is a need of highly understanding mobile marketing strategies, how to launch a mobile campaign for a mobile game. Besides that, it is essential to understand the relationship between mobile advertising and users behaviours. There...

  17. An insulating grid spacer for large-area MICROMEGAS chambers

    CERN Document Server

    Bernard, D; D'Enterria, D G; Le Guay, M; Martínez, G; Mora, M J; Pichot, P; Roy, D; Schutz, Y; Gandi, A; De Oliveira, R

    2002-01-01

    We present an original design for large area gaseous detectors based on the MICROMEGAS technology. This technology incorporates an insulating grid, sandwiched between the micro-mesh and the anode-pad plane, which provides an uniform 200 $\\mu$m amplification gap. The uniformity of the amplification gap thickness has been verified under several experimental conditions. The gain performances of the detector are presented and compared to the values obtained with detectors using cylindrical micro spacers. The new design presents several technical and financial advantages.

  18. Spacer grid with mixing blades for nuclear fuel assembly

    International Nuclear Information System (INIS)

    Noailly, J.

    1986-01-01

    The spacer grid for nuclear fuel assembly has two sets of intersecting metal plates provided with blades and defining cells. The plates are fitted only with half-blades associated with a single grid opening. The half-blades of adjacent cells are arranged at 90deg C to each other and each plate has at most one half-blade at each corner of a cell. The invention concerns fuel assemblies of pressurized water reactors. The blades arranged on a single side of the plate provide a good hydraulic uniformity. The invention provides a uniform distribution of blades (and thus of absorbing material in each hydraulic cell) [fr

  19. In vitro microbiologic evaluation of PTFE and cotton as spacer materials.

    Science.gov (United States)

    Paranjpe, Avina; Jain, Sumita; Alibhai, Karim J; Wadhwani, Chandur P; Darveau, Richard P; Johnson, James D

    2012-09-01

    To microbiologically evaluate the efficacy of cotton and polytetrafluoroethylene (PTFE) tape used as spacer materials. Twenty-six extracted human molars were restored using either cotton or PTFE tape as spacers under a standardized provisional restorative material (Cavit). The teeth were incubated for 7 days in a culture of Streptococcus gordonii or in liquid media alone. The spacers were removed and tested for bacterial contamination. The access cavities were also evaluated for bacterial contamination. Nine of 10 teeth with cotton spacers and one of 10 teeth with PTFE spacers were positive for S gordonii growth. The nine teeth in the cotton group also showed contamination of the access cavities. Even under optimal conditions, cotton spacers may cause leakage into the access cavities. Cotton fibers may serve as a route for bacterial contamination of the access cavities and root canal space. In contrast, PTFE tape did not provide an avenue for bacterial contamination.

  20. Transcriptional regulator-mediated activation of adaptation genes triggers CRISPR de novo spacer acquisition

    DEFF Research Database (Denmark)

    Liu, Tao; Li, Yingjun; Wang, Xiaodi

    2015-01-01

    Acquisition of de novo spacer sequences confers CRISPR-Cas with a memory to defend against invading genetic elements. However, the mechanism of regulation of CRISPR spacer acquisition remains unknown. Here we examine the transcriptional regulation of the conserved spacer acquisition genes in Type I......, it was demonstrated that the transcription level of csa1, cas1, cas2 and cas4 was significantly enhanced in a csa3a-overexpression strain and, moreover, the Csa1 and Cas1 protein levels were increased in this strain. Furthermore, we demonstrated the hyperactive uptake of unique spacers within both CRISPR loci...... in the presence of the csa3a overexpression vector. The spacer acquisition process is dependent on the CCN PAM sequence and protospacer selection is random and non-directional. These results suggested a regulation mechanism of CRISPR spacer acquisition where a single transcriptional regulator senses the presence...

  1. Electrostatic charge on a plastic spacer device influences the delivery of salbutamol.

    Science.gov (United States)

    Wildhaber, J H; Devadason, S G; Hayden, M J; James, R; Dufty, A P; Fox, R A; Summers, Q A; LeSouëf, P N

    1996-09-01

    The aim of this study was to determine whether electrostatic charge on a plastic spacer decreases the delivery of salbutamol from a pressurized metered-dose inhaler (pMDI) and, if so, to find an optimal and practical treatment to remove the charge. Ten single actuations from a salbutamol pMDI were drawn through different Volumatic spacers at a constant flow of 60 L.min-1. The efficacies of different methods of removing charge were tested, including detergent coating of the spacers. A multistage liquid impinger was used to determine the particle size distribution of the output of the pMDI through the Volumatic spacers. The electrostatic charge on the inner surface of the spacers was measured both quantitatively with an electrometer, and qualitatively by the attraction of a thin strip of cellulose membrane to the wall of the spacer. Each experiment was repeated four times. Ionic detergent coating of the spacers removed the charge for at least 24 h. This resulted in an increase of 55-70% in small particle (< 6.8 microns) delivery compared to delivery from new spacers with high charge. We have demonstrated that electrostatic charge plays a major role in the delivery of salbutamol through plastic spacers. Adequate treatment with ionic detergent removes the charge and improves drug delivery.

  2. Nanoparticle-Based Brachytherapy Spacers for Delivery of Localized Combined Chemoradiation Therapy

    International Nuclear Information System (INIS)

    Kumar, Rajiv; Belz, Jodi; Markovic, Stacey; Jadhav, Tej; Fowle, William; Niedre, Mark; Cormack, Robert; Makrigiorgos, Mike G.; Sridhar, Srinivas

    2015-01-01

    Purpose: In radiation therapy (RT), brachytherapy-inert source spacers are commonly used in clinical practice to achieve high spatial accuracy. These implanted devices are critical technical components of precise radiation delivery but provide no direct therapeutic benefits. Methods and Materials: Here we have fabricated implantable nanoplatforms or chemoradiation therapy (INCeRT) spacers loaded with silica nanoparticles (SNPs) conjugated containing a drug, to act as a slow-release drug depot for simultaneous localized chemoradiation therapy. The spacers are made of poly(lactic-co-glycolic) acid (PLGA) as matrix and are physically identical in size to the commercially available brachytherapy spacers (5 mm × 0.8 mm). The silica nanoparticles, 250 nm in diameter, were conjugated with near infrared fluorophore Cy7.5 as a model drug, and the INCeRT spacers were characterized in terms of size, morphology, and composition using different instrumentation techniques. The spacers were further doped with an anticancer drug, docetaxel. We evaluated the in vivo stability, biocompatibility, and biodegradation of these spacers in live mouse tissues. Results: The electron microscopy studies showed that nanoparticles were distributed throughout the spacers. These INCeRT spacers remained stable and can be tracked by the use of optical fluorescence. In vivo optical imaging studies showed a slow diffusion of nanoparticles from the spacer to the adjacent tissue in contrast to the control Cy7.5-PLGA spacer, which showed rapid disintegration in a few days with a burst release of Cy7.5. The docetaxel spacers showed suppression of tumor growth in contrast to control mice over 16 days. Conclusions: The imaging with the Cy7.5 spacer and therapeutic efficacy with docetaxel spacers supports the hypothesis that INCeRT spacers can be used for delivering the drugs in a slow, sustained manner in conjunction with brachytherapy, in contrast to the rapid clearance of the drugs when

  3. Single-electron transistors fabricated with sidewall spacer patterning

    Science.gov (United States)

    Park, Byung-Gook; Kim, Dae Hwan; Kim, Kyung Rok; Song, Ki-Whan; Lee, Jong Duk

    2003-09-01

    We have implemented a sidewall spacer patterning method for novel dual-gate single-electron transistor (DGSET) and metal-oxide-semiconductor-based SET (MOSET) based on the uniform SOI wire, using conventional lithography and processing technology. A 30 nm wide silicon quantum wire is defined by a sidewall spacer patterning method, and depletion gates for two tunnel junctions of the DGSET are formed by the doped polycrystalline silicon sidewall. The fabricated DGSET and MOSET show clear single-electron tunneling phenomena at liquid nitrogen temperature and insensitivity of the Coulomb oscillation period to gate bias conditions. On the basis of the phase control capability of the sidewall depletion gates, we have proposed a complementary self-biasing method, which enables the SET/CMOS hybrid multi-valued logic (MVL) to operate perfectly well at high temperature, where the peak-to-valley current ratio of Coulomb oscillation severely decreases. The suggested scheme is evaluated by SPICE simulation with an analytical DGSET model, and it is confirmed that even DGSETs with a large Si island can be utilized efficiently in the multi-valued logic.

  4. Functional analysis of transcribed spacers of yeast ribosomal DNA.

    Science.gov (United States)

    Musters, W; Boon, K; van der Sande, C A; van Heerikhuizen, H; Planta, R J

    1990-12-01

    Making use of an rDNA unit, containing oligonucleotide tags in both the 17S and 26S rRNA gene, we have analyzed the effect of various deletions in the External Transcribed Spacer (ETS) and in one of the Internal Transcribed Spacers 1 (ITS1) on the process of ribosome formation in yeast. By following the fate of the tagged transcripts of this rDNA unit in vivo by Northern hybridization we found that deleting various parts of the ETS prevents the accumulation of tagged 17S rRNA and its assembly into 40S subunits, but not the formation of 60S subunits. Deleting the central region of ITS1, including a processing site that is used in an early stage of the maturation process, was also found to prevent the accumulation of functional 49 S subunits, whereas no effect on the formation of 60S subunits was detected. The implications of these findings for yeast pre-rRNA processing are discussed.

  5. Technical modification enabling pulmonary valve-sparing repair of a severely hypoplastic pulmonary annulus in patients with tetralogy of Fallot.

    Science.gov (United States)

    Ito, Hiroki; Ota, Noritaka; Murata, Masaya; Tosaka, Yuko; Ide, Yujiro; Tachi, Maiko; Sugimoto, Ai; Sakamoto, Kisaburo

    2013-06-01

    Although pulmonary valve-sparing repair is preferable for patients with tetralogy of Fallot, the repair of very small pulmonary valves is challenging. The present study evaluates our modification for preserving severely hypoplastic pulmonary valves in patients with tetralogy of Fallot. Sixty-eight consecutive patients who underwent complete repair of a tetralogy of Fallot between 2005 and 2011 were retrospectively reviewed. Patients with pulmonary atresia, absence of a pulmonary valve, atrioventricular septal defect and/or subarterial ventricular septal defect were excluded. There were 19 (28%) patients with a severely hypoplastic pulmonary annulus determined by preoperative echocardiography (z-score -4 group. In the z tetralogy of Fallot could not be applied in all patients, this strategy enabled acceptable growth of the valve annulus, with only mild stenosis during the early to mid-term follow-up. This modification seems to be an option, even for a very small pulmonary valve.

  6. Analytical solution for pulsatile viscous flow in a straight elliptic annulus and application to the motion of the cerebrospinal fluid

    Science.gov (United States)

    Gupta, Sumeet; Poulikakos, Dimos; Kurtcuoglu, Vartan

    2008-09-01

    We present here the analytical solution of transient, laminar, viscous flow of an incompressible, Newtonian fluid driven by a harmonically oscillating pressure gradient in a straight elliptic annulus. The analytical formulation is based on the exact solution of the governing fluid flow equations known as Navier-Stokes equations. We validate the analytical solution using a finite-volume computational fluid dynamics approach. As the analytical solution includes Mathieu and modified Mathieu functions, we also present a stepwise procedure for their evaluation for large complex arguments typically associated with viscous flows. We further outline the procedure for evaluating the associated Fourier coefficients and their eigenvalues. We finally apply the analytical solution to investigate the cerebrospinal fluid flow in the human spinal cavity, which features a shape similar to an elliptic annulus.

  7. Two-phase magnetoconvection flow of magnetite (Fe3O4) nanoparticles in a horizontal composite porous annulus

    Science.gov (United States)

    Abbas, Zaheer; Hasnain, Jafar

    A numerical study is performed to examine the two-phase magnetoconvection and heat transfer phenomena of Fe3O4 -kerosene nanofluid flow in a horizontal composite porous annulus with an external magnetic field. The annulus is filled with immiscible fluids flowing between two concentric cylinders. The governing equations of the flow problem are obtained using Darcy-Brinkman model. Heat transfer is analyzed in the presence of viscous and Darcian dissipation terms. The shooting method is used as a tool to solve the obtained non-linear ordinary differential equations for the velocity and temperature profiles. The velocity and temperature distributions are analyzed and discussed under the influence of involved flow parameters with the aid of graphs. It is found that both velocity and temperature of fluid are decreased with ferroparticle volume fraction. In addition to that, it is also presented that the existence of magnetic field decreases the benefit of ferrofluids in heat transfer progression.

  8. Intervertebral Disc Degeneration : The Role of the Mitochondrial Pathway in Annulus Fibrosus Cell Apoptosis Induced by Overload

    OpenAIRE

    Rannou, François; Lee, Tzong-Shyuan; Zhou, Rui-Hai; Chin, Jennie; Lotz, Jeffrey C.; Mayoux-Benhamou, Marie-Anne; Barbet, Jacques Patrick; Chevrot, Alain; Shyy, John Y.-J.

    2004-01-01

    Degeneration of the intervertebral disk (IVD) is a major pathological process implicated in low back pain and is a prerequisite to disk herniation. Although mechanical stress is an important modulator of the degeneration, the underlying molecular mechanism remains unclear. The association of human IVD degeneration, assessed by magnetic resonance imaging, with annulus fibrosus cell apoptosis and anti-cytochrome c staining revealed that the activation of the mitochondria-dependent apoptosome wa...

  9. Mechanics of oriented electrospun nanofibrous scaffolds for annulus fibrosus tissue engineering.

    Science.gov (United States)

    Nerurkar, Nandan L; Elliott, Dawn M; Mauck, Robert L

    2007-08-01

    Engineering a functional replacement for the annulus fibrosus (AF) of the intervertebral disc is contingent upon recapitulation of AF structure, composition, and mechanical properties. In this study, we propose a new paradigm for AF tissue engineering that focuses on the reconstitution of anatomic fiber architecture and uses constitutive modeling to evaluate construct function. A modified electrospinning technique was utilized to generate aligned nanofibrous polymer scaffolds for engineering the basic functional unit of the AF, a single lamella. Scaffolds were tested in uniaxial tension at multiple fiber orientations, demonstrating a nonlinear dependence of modulus on fiber angle that mimicked the nonlinearity and anisotropy of native AF. A homogenization model previously applied to native AF successfully described scaffold mechanical response, and parametric studies demonstrated that nonfibrillar matrix, along with fiber connectivity, are key contributors to tensile mechanics for engineered AF. We demonstrated that AF cells orient themselves along the aligned scaffolds and deposit matrix that contributes to construct mechanics under loading conditions relevant to the in vivo environment. The homogenization model was applied to cell-seeded constructs and provided quantitative measures for the evolution of matrix and interfibrillar interactions. Finally, the model demonstrated that at fiber angles of the AF (28 degrees -44 degrees ), engineered material behaved much like native tissue, suggesting that engineered constructs replicate the physiologic behavior of the single AF lamella. Constitutive modeling provides a powerful tool for analysis of engineered AF neo-tissue and native AF tissue alike, highlighting key mechanical design criteria for functional AF tissue engineering.

  10. Estimates of the Hyperbolic Radius Gradient and Schwarz–Pick Inequalities for the Eccentric Annulus

    Directory of Open Access Journals (Sweden)

    D.Kh. Giniyatova

    2016-06-01

    Full Text Available Let Ω and Π be hyperbolic domains in the complex plane C. By A(Ω, Π we shall designate the class of functions f which are holomorphic or meromorphic in Ω and such that f(Ω ϲ Π. Estimates of the higher derivatives |f(n(z| of the analytic functions from the class A(Ω, Π with the punishing factor Cn(Ω, Π is one of the main problems of geometric theory of functions. These estimates are commonly referred to as Schwarz–Pick inequalities. Many results concerning this problem have been obtained for simply connected domains. Therefore, the research interest in such problems for finitely connected domains is natural. As known, the constant C2(Ω, Π for any pairs of hyperbolic domains depends only on the hyperbolic radius gradient of the corresponding domains. The main result of this paper is estimates of the hyperbolic radius gradient and the punishing factor in the Schwarz–Pick inequality for the eccentric annulus. We also consider the extreme case – the randomly punctured circle.

  11. Ultrastructure of inclusion bodies in annulus cells in the degenerating human intervertebral disc.

    Science.gov (United States)

    Gruber, H E; Hanley, E N

    2009-06-01

    The rough endoplasmic reticulum (rER) of the cell has an architectural editing function that checks whether protein structure and three-dimensional assembly have occurred properly prior to export of newly synthesized material out of the cell. If these have been faulty, the material is retained within the rER as an inclusion body. Inclusion bodies have been identified previously in chondrocytes and osteoblasts in chondrodysplasias and osteogenesis imperfecta. Inclusion bodies in intervertebral disc cells, however, have only recently been recognized. Our objectives were to use transmission electron microscopy to analyze more fully inclusion bodies in the annulus pulposus and to study the extracellular matrix (ECM) surrounding cells containing inclusion bodies. ECM frequently encapsulated cells with inclusion bodies, and commonly contained prominent banded aggregates of Type VI collagen. Inclusion body material had several morphologies, including relatively smooth, homogeneous material, or a rougher, less homogeneous feature. Such findings expand our knowledge of the fine structure of the human disc cell and ECM during disc degeneration, and indicate the potential utility of ultrastructural identification of discs with intracellular inclusion bodies as a screening method for molecular studies directed toward identification of defective gene products in degenerating discs.

  12. Numerical Study of Mixed Convection of Nanofluid in a Concentric Annulus with Rotating Inner Cylinder

    Directory of Open Access Journals (Sweden)

    G. A. Sheikhzadeh

    2013-01-01

    Full Text Available In this work, the steady and laminar mixed convection of nanofluid in horizontal concentric annulus withrotating inner cylinder is investigated numerically. The inner and outer cylinders are kept at constanttemperature Ti and To respectively, where Ti>To. The annular space is filled with Alumina-water nanofluid.The governing equations with the corresponded boundary conditions in the polar coordinate are discretizedusing the finite volume method where pressure-velocity coupling is done by the SIMPLER algorithm.Numerical results have been obtained for Rayleigh number ranging from 102 to 105, Reynolds number from 1 to 300 and nanoparticles volume fraction from 0.01 to 0.06. The effects of the Reynolds and Rayleigh numbers, average diameter of nanoparticles and the volume fraction of the nanoparticles on the fluid flow and heat transfer inside the annuli are investigated. According to the results, the average Nusselt number decreases with increasing the Reynolds number. However, the average Nusselt number increases by increasing the Rayleigh number. Moreover, the maximum average Nusselt number occurs for an optimal nanoparticle volume fraction except situations that heat conduction predominates over the heat convection. In these conditions the average Nusselt number is close to unity.

  13. A numerical study of Taylor vortex flow in a finite length tapered annulus

    International Nuclear Information System (INIS)

    Noui-Mehidi, M N; Ohmura, N; Wu, J

    2005-01-01

    The transient evolution and steady state analysis of Taylor vortex flow in a tapered annulus was conducted by numerical experiments in the case where the inner cylinder was rotated and the outer one fixed. The gap between the cylinders was linearly tapered from a supercritical value at the upper base to the critical value at the lower base. The wavelength adjustment depended on the variation of Reynolds number in the spatially ramped gap. The axisymmetric conservative governing equations were solved by the use of an simplified marker and cell (SMAC) algorithm. A coordinate transformation function allowed us to numerically solve the problem in a rectangular computational domain. The results have shown that Taylor vortices growth was sensitive to the spatial ramp of the gap even with tapering angle values less than one degree. The interaction between the inflow and outflow boundaries could be clearly seen as the taper angle was increased. The investigation of the transient dynamics related to the flow system also revealed a characteristic dependence on the taper angle

  14. CFD Calculation of Internal Natural Convection in the Annulus between Horizontal Concentric Cylinders

    Energy Technology Data Exchange (ETDEWEB)

    N.D. Francis, Jr; M.T. Itamura; S.W. Webb; D.L. James

    2002-10-01

    The objective of this heat transfer and fluid flow study is to assess the ability of a computational fluid dynamics (CFD) code to reproduce the experimental results, numerical simulation results, and heat transfer correlation equations developed in the literature for natural convection heat transfer within the annulus of horizontal concentric cylinders. In the literature, a variety of heat transfer expressions have been developed to compute average equivalent thermal conductivities. However, the expressions have been primarily developed for very small inner and outer cylinder radii and gap-widths. In this comparative study, interest is primarily focused on large gap widths (on the order of half meter or greater) and large radius ratios. From the steady-state CFD analysis it is found that the concentric cylinder models for the larger geometries compare favorably to the results of the Kuehn and Goldstein correlations in the Rayleigh number range of about 10{sup 5} to 10{sup 8} (a range that encompasses the laminar to turbulent transition). For Rayleigh numbers greater than 10{sup 8}, both numerical simulations and experimental data (from the literature) are consistent and result in slightly lower equivalent thermal conductivities than those obtained from the Kuehn and Goldstein correlations.

  15. A numerical study on the non-Boussinesq effect in the natural convection in horizontal annulus

    Science.gov (United States)

    Zhang, Yu; Cao, Yuhui

    2018-04-01

    In the present study, the non-Boussinesq effect in the thermal convection in an air-filled horizontal concentric annulus is studied numerically by using the variable property-based lattice Boltzmann flux solver (VPLBFS), with the radial temperature difference ratio of 1.0, the radius ratio of 2.0, and the Rayleigh number in the range 104 ≤ Ra ≤ 106. Several solutions are obtained by using the standard form or simplified versions of the VPLBFS, including the real solution with the total variation in fluid properties considered, named as the variable property solution (VPS), the constant property solution (CPS) based on the Boussinesq approximation, the solution with variable dynamic viscosity (VVS), the solution based on the partial Boussinesq approximation (PBAS), the solution with variable thermal conductivity (VCS) and the solution with variable fluid density (VDS). The discrepancy between these solutions is analyzed to illuminate the influence of the non-Boussinesq effects induced by partial or total variation in fluid properties on flow instability behaviors and heat transfer characteristics. The present study reveals the complicated flow instability behavior under non-Boussinesq conditions and its tight association with heat transfer characteristics. Also, it demonstrates the necessity of considering the integral effect of the total variation in fluid properties and highlights the essential role of the fluid density variation.

  16. Experimental evaluation of local bubble parameters of subcooled boiling flow in a pressurized vertical annulus channel

    Energy Technology Data Exchange (ETDEWEB)

    Chu, In-Cheol, E-mail: chuic@kaeri.re.kr; Lee, Seung-Jun; Youn, Young Jung; Park, Jong Kuk; Choi, Hae Seob; Euh, Dong-Jin; Song, Chul-Hwa

    2017-02-15

    Experiments were performed to quantify the local bubble parameters such as void fraction, bubble velocity, interfacial area concentration, and Sauter mean diameter for the subcooled boiling flow of a refrigerant R-134a in a pressurized vertical annulus channel. Optical fiber void probe and double pressure boundary visualization windows were installed at four measurement stations with different elevations, thus enabling the quantification of local bubble parameters and observation of global boiling structure. Using high-resolution traverse systems for the optical fiber void probes and the heating tube, the radial profiles of the bubble parameters and their axial propagation can be evaluated at any elevation of the whole heating region. At this first phase of the experiments, three tests were conducted by varying the pressure, heat flux, mass flux, and local liquid subcooling. The radial profiles of the bubble parameters were obtained at seven elevations. The pressure condition of the present experiments covered the normal operating pressure of PWRs according to the similarity criteria. The present experimental data will be useful for thorough validation and improvement of the CMFD (Computation Multi-Fluid Dynamics) codes and constitutive relations.

  17. New bounded skew central difference scheme. Part 2: Application to natural convection in an eccentric annulus

    Energy Technology Data Exchange (ETDEWEB)

    Moukalled, F.; Darwish, M. [American Univ. of Beirut (Lebanon)

    1997-01-01

    The bounded skew central difference scheme (NVF SCDS) is used to study numerically the combined effect of vertical ({epsilon}{sub y}) and horizontal ({epsilon}{sub x}) eccentricities on natural convection in an annulus between a heated horizontal cylinder and its square enclosure. Four Rayleigh numbers (Ra = 10{sup 3}, 10{sup 4}, 10{sup 5}, and 10{sup 6}), three aspect ratios (R/L = 0.1, 0.2, and 0.3), and eccentricity values ranging from {minus}0.3 to 0.3 are considered. At constant enclosure aspect ratio, the total heat transfer increases with increasing Rayleigh number. For constant Rayleigh-number values, convection contribution to total heat transfer decreases with increasing values of R/L. For conduction-dominated flows, heat transfer increases with increasing {vert_bar}{epsilon}{sub y}{vert_bar} and/or {vert_bar}{epsilon}{sub x}{vert_bar}. For convection-dominated flows, heat transfer increases with decreasing {epsilon}{sub y} for {epsilon}{sub y} < 0, decreases with increasing {epsilon}{sub y} for {epsilon}{sub y} > 0, and decreases with decreasing {epsilon}{sub x} for {epsilon}{sub x} < 0. For the case when conduction and convection are of equal importance, there is a critical {epsilon}{sub x} for which the total heat transfer is minimum.

  18. CFD Calculation of Internal Natural Convection in the Annulus between Horizontal Concentric Cylinders

    International Nuclear Information System (INIS)

    Francis, N.D. Jr.; Itamura, M.T.; Webb, S.W.; James, D.L.

    2002-01-01

    The objective of this heat transfer and fluid flow study is to assess the ability of a computational fluid dynamics (CFD) code to reproduce the experimental results, numerical simulation results, and heat transfer correlation equations developed in the literature for natural convection heat transfer within the annulus of horizontal concentric cylinders. In the literature, a variety of heat transfer expressions have been developed to compute average equivalent thermal conductivities. However, the expressions have been primarily developed for very small inner and outer cylinder radii and gap-widths. In this comparative study, interest is primarily focused on large gap widths (on the order of half meter or greater) and large radius ratios. From the steady-state CFD analysis it is found that the concentric cylinder models for the larger geometries compare favorably to the results of the Kuehn and Goldstein correlations in the Rayleigh number range of about 10 5 to 10 8 (a range that encompasses the laminar to turbulent transition). For Rayleigh numbers greater than 10 8 , both numerical simulations and experimental data (from the literature) are consistent and result in slightly lower equivalent thermal conductivities than those obtained from the Kuehn and Goldstein correlations

  19. Chaotic micromixer utilizing electro-osmosis and induced charge electro-osmosis in eccentric annulus

    International Nuclear Information System (INIS)

    Feng, Huicheng; Wong, Teck Neng; Marcos; Che, Zhizhao

    2016-01-01

    Efficient mixing is of significant importance in numerous chemical and biomedical applications but difficult to realize rapidly in microgeometries due to the lack of turbulence. We propose to enhance mixing by introducing Lagrangian chaos through electro-osmosis (EO) or induced charge electro-osmosis (ICEO) in an eccentric annulus. The analysis reveals that the created Lagrangian chaos can achieve a homogeneous mixing much more rapidly than either the pure EO or the pure ICEO. Our systematic investigations on the key parameters, ranging from the eccentricity, the alternating time period, the number of flow patterns in one time period, to the specific flow patterns utilized for the Lagrangian chaos creation, present that the Lagrangian chaos is considerably robust. The system can obtain a good mixing effect with wide ranges of eccentricity, alternating time period, and specific flow patterns utilized for the Lagrangian chaos creation as long as the number of flow patterns in one time period is two. As the electric field increases, the time consumption for homogenous mixing is reduced more remarkably for the Lagrangian chaos of the ICEO than that of the EO.

  20. Molecular Imaging Agents Specific for the Annulus Fibrosus of the Intervertebral Disk

    Directory of Open Access Journals (Sweden)

    Summer L. Gibbs-Strauss

    2010-05-01

    Full Text Available Low back pain is a prevalent medical condition that is difficult to diagnose and treat. Current imaging methods are unable to correlate pain reliably with spinal structures, and surgical removal of painful damaged or degenerating disks is technically challenging. A contrast agent specific for the intervertebral disk could assist in the detection, diagnosis, and surgical treatment of low back pain. The styryl pyridinium (FM fluorophores were characterized and structure-activity relationships between chemical structure and in vivo uptake were established. Two novel FM fluorophores with improved optical properties for imaging the intervertebral disks were synthesized and evaluated in mice, rats, and pigs. After a single systemic injection, eight of eight FM fluorophores provided high-contrast imaging of the trigeminal ganglia, whereas six of eight provided high-contrast imaging of the dorsal root ganglia. Unexpectedly, three of eight FM fluorophores provided high-contrast imaging of annulus fibrosus tissue of the intervertebral disks, confirmed histologically. We present the first known contrast agent specific for the intervertebral disks and identify the chemical structural motif that mediates uptake. FM fluorophores could be used for image-guided surgery to assist in the removal of intervertebral disk and lay the foundation for derivatives for magnetic resonance imaging and positron emission tomography.

  1. Oil flow in the oil well tube annulus of vertical bearing assemblies (leakage)

    International Nuclear Information System (INIS)

    Piao, Yinghu

    1997-01-01

    A numerical simulation and experimental flow visualization study was conducted to better understand oil well leakage, particularly in the annular clearance space surrounding the oil well tube. A test rig was developed to simulate the bearing's oil well tube annulus. A major feature of this rig was to allow visual access to the annular clearance space and to the region beneath the rotating runner where strong secondary flow effects are known to exist. The main method for tracing the secondary flow pathlines was a light sheet visualization technique using micro air bubbles as the tracer. The effect of runner speed on the pathlines was studied. The velocity of the oil flow was measured experimentally and the results were compared with numerical data. A numerical technique was developed to trace the micro air bubbles in the oil flow field using a three dimensional CFD code for laminar, axisymmetric flow with a free surface. The buoyancy effects of gravitational and centrifugal forces were considered when determining the pathline of air bubbles. Bubble size, oil viscosity and runner speed were some of the parameters that affect the path of the air bubbles

  2. Simultaneous effects of single wall carbon nanotube and effective variable viscosity for peristaltic flow through annulus having permeable walls

    Directory of Open Access Journals (Sweden)

    Iqra Shahzadi

    Full Text Available The current article deals with the combine effects of single wall carbon nanotubes and effective viscosity for the peristaltic flow of nanofluid through annulus. The nature of the walls is assumed to be permeable. The present theoretical model can be considered as mathematical representation to the motion of conductive physiological fluids in the existence of the endoscope tube which has many biomedical applications such as drug delivery system. The outer tube has a wave of sinusoidal nature that is travelling along its walls while the inner tube is rigid and uniform. Lubrication approach is used for the considered analysis. An empirical relation for the effective variable viscosity of nanofluid is proposed here interestingly. The viscosity of nanofluid is the function of radial distance and the concentration of nanoparticles. Exact solution for the resulting system of equations is displayed for various quantities of interest. The outcomes show that the maximum velocity of SWCNT-blood nanofluid enhances for larger values of viscosity parameter. The pressure gradient in the more extensive part of the annulus is likewise found to increase as a function of variable viscosity parameter. The size of the trapped bolus is also influenced by variable viscosity parameter. The present examination also revealed that the carbon nanotubes have many applications related to biomedicine. Keywords: Variable nanofluid viscosity, SWCNT, Annulus, Permeable walls, Exact solution

  3. The Development of a Gas–Liquid Two-Phase Flow Sensor Applicable to CBM Wellbore Annulus

    Science.gov (United States)

    Wu, Chuan; Wen, Guojun; Han, Lei; Wu, Xiaoming

    2016-01-01

    The measurement of wellbore annulus gas–liquid two-phase flow in CBM (coalbed methane) wells is of great significance for reasonably developing gas drainage and extraction processes, estimating CBM output, judging the operating conditions of CBM wells and analyzing stratum conditions. Hence, a specially designed sensor is urgently needed for real-time measurement of gas–liquid two-phase flow in CBM wellbore annulus. Existing flow sensors fail to meet the requirements of the operating conditions of CBM wellbore annulus due to such factors as an inapplicable measurement principle, larger size, poor sealability, high installation accuracy, and higher requirements for fluid media. Therefore, based on the principle of a target flowmeter, this paper designs a new two-phase flow sensor that can identify and automatically calibrate different flow patterns of two-phase flows. Upon the successful development of the new flow sensor, lab and field tests were carried out, and the results show that the newly designed sensor, with a measurement accuracy of ±2.5%, can adapt to the operating conditions of CBM wells and is reliable for long-term work. PMID:27869708

  4. The Development of a Gas-Liquid Two-Phase Flow Sensor Applicable to CBM Wellbore Annulus.

    Science.gov (United States)

    Wu, Chuan; Wen, Guojun; Han, Lei; Wu, Xiaoming

    2016-11-18

    The measurement of wellbore annulus gas-liquid two-phase flow in CBM (coalbed methane) wells is of great significance for reasonably developing gas drainage and extraction processes, estimating CBM output, judging the operating conditions of CBM wells and analyzing stratum conditions. Hence, a specially designed sensor is urgently needed for real-time measurement of gas-liquid two-phase flow in CBM wellbore annulus. Existing flow sensors fail to meet the requirements of the operating conditions of CBM wellbore annulus due to such factors as an inapplicable measurement principle, larger size, poor sealability, high installation accuracy, and higher requirements for fluid media. Therefore, based on the principle of a target flowmeter, this paper designs a new two-phase flow sensor that can identify and automatically calibrate different flow patterns of two-phase flows. Upon the successful development of the new flow sensor, lab and field tests were carried out, and the results show that the newly designed sensor, with a measurement accuracy of ±2.5%, can adapt to the operating conditions of CBM wells and is reliable for long-term work.

  5. Two-phase magnetoconvection flow of magnetite (Fe3O4 nanoparticles in a horizontal composite porous annulus

    Directory of Open Access Journals (Sweden)

    Zaheer Abbas

    Full Text Available A numerical study is performed to examine the two-phase magnetoconvection and heat transfer phenomena of Fe3O4 -kerosene nanofluid flow in a horizontal composite porous annulus with an external magnetic field. The annulus is filled with immiscible fluids flowing between two concentric cylinders. The governing equations of the flow problem are obtained using Darcy-Brinkman model. Heat transfer is analyzed in the presence of viscous and Darcian dissipation terms. The shooting method is used as a tool to solve the obtained non-linear ordinary differential equations for the velocity and temperature profiles. The velocity and temperature distributions are analyzed and discussed under the influence of involved flow parameters with the aid of graphs. It is found that both velocity and temperature of fluid are decreased with ferroparticle volume fraction. In addition to that, it is also presented that the existence of magnetic field decreases the benefit of ferrofluids in heat transfer progression. Keywords: Two-phase flow, Nanofluid, Porous medium, Magnetoconvection, Horizontal annulus

  6. Long-Term Outcomes of Permanent Cement Spacers in the Infected Foot.

    Science.gov (United States)

    Elmarsafi, Tammer; Oliver, Noah G; Steinberg, John S; Evans, Karen K; Attinger, Christopher E; Kim, Paul J

    When osteomyelitis occurs in the infected foot, cement spacers have been used as a limb salvage tool. The aim of the present study was to assess the longevity and outcomes in high-risk, low-demand patients who have undergone resection of bone and subsequent placement of permanent antibiotic-eluting cement spacers in the foot. A retrospective review case series of 30 patients who had undergone placement of a permanent antibiotic-eluting cement spacer in the foot were evaluated for retention, spacer exchange, removal, amputation, and functional status. The minimum follow-up time for inclusion was 12 months. Two thirds of all patients had successful spacers (n = 20) that were either retained (n = 14) or successfully exchanged (n = 6). One third of all patients experienced spacer failure (n = 10) and required removal. Of the 10 patients requiring spacer removal, 4 underwent removal with subsequent arthrodesis and 6 underwent removal with subsequent pseudoarthrosis. Also, 8 of these patients (26.7%) required partial foot amputation of the ipsilateral foot. These amputations were not directly related to the use or removal of the spacer. The average time to spacer removal or partial amputation was 20.9 (range 0.2 to 60.9) months. The longest retained spacer in the foot was 76 months at the last follow-up visit. The longest exchanged spacer at the last follow-up visit was 111 months. All surviving patients were ambulatory at the last follow-up visit. Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  7. The influence of the preliminary garter spring spacer simulator clamping force in the pressure tube spacer -calandria tube hook-up simulator aging behaviour

    International Nuclear Information System (INIS)

    Gyongyosi, T.; Deloreanu, G.; Puiu, D.; Corbescu, B.; Anghel, N.; Dinu, E.

    2016-01-01

    The garter spring spacer is a specially constructed torsion spring used to fit-out the CANDU 6 fuel channel. The pressure tube ageing decreases the gap to the calandria tube. Continuous gap decrease directly affects the garter spring spacers behavior during fuel channel assembly operation. The preliminary clamping force value of the garter spring spacer assembly is important for its ageing behavior. This paper briefly describes the experimental technological facilities used for conducted the experiments and highlights some of the important moments during an experiment carried out in laboratory conditions, without using pressurized boiled water and irradiation working conditions. The results analysis and some conclusions are outlined at the end, pointing out that a garter spring spacer preliminary clamping force increase reduces the vibration response signal amplitude, and does not lead to its relaxation. The paper is dedicated to specialists working in research and technological engineering. (authors)

  8. Cas4 Facilitates PAM-Compatible Spacer Selection during CRISPR Adaptation.

    Science.gov (United States)

    Kieper, Sebastian N; Almendros, Cristóbal; Behler, Juliane; McKenzie, Rebecca E; Nobrega, Franklin L; Haagsma, Anna C; Vink, Jochem N A; Hess, Wolfgang R; Brouns, Stan J J

    2018-03-27

    CRISPR-Cas systems adapt their immunological memory against their invaders by integrating short DNA fragments into clustered regularly interspaced short palindromic repeat (CRISPR) loci. While Cas1 and Cas2 make up the core machinery of the CRISPR integration process, various class I and II CRISPR-Cas systems encode Cas4 proteins for which the role is unknown. Here, we introduced the CRISPR adaptation genes cas1, cas2, and cas4 from the type I-D CRISPR-Cas system of Synechocystis sp. 6803 into Escherichia coli and observed that cas4 is strictly required for the selection of targets with protospacer adjacent motifs (PAMs) conferring I-D CRISPR interference in the native host Synechocystis. We propose a model in which Cas4 assists the CRISPR adaptation complex Cas1-2 by providing DNA substrates tailored for the correct PAM. Introducing functional spacers that target DNA sequences with the correct PAM is key to successful CRISPR interference, providing a better chance of surviving infection by mobile genetic elements. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

  9. Magnetic decoupling of ferromagnetic metals through a graphene spacer

    Energy Technology Data Exchange (ETDEWEB)

    Grimaldi, I.; Papagno, M. [Dipartimento di Fisica, Universitá della Calabria, Arcavacata di Rende (CS), 87036 (Italy); Ferrari, L. [Istituto dei Sistemi Complessi, Consiglio Nazionale delle Ricerche, Roma I-00133 (Italy); Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Trieste (Italy); Sheverdyaeva, P.M.; Mahatha, S.K. [Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Trieste (Italy); Pacilé, D., E-mail: daniela.pacile@fis.unical.it [Dipartimento di Fisica, Universitá della Calabria, Arcavacata di Rende (CS), 87036 (Italy); Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Trieste (Italy); Carbone, C. [Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Trieste (Italy)

    2017-03-15

    We study the magnetic coupling between different ferromagnetic metals (FMs) across a graphene (G) layer, and the role of graphene as a thin covalent spacer. Starting with G grown on a FM substrate (Ni or Co), we deposited on top at room temperature several FM metals (Fe, Ni, Co). By measuring the dichroic effect of 3p photoemission lines we detect the magnetization of the substrate and the sign of the exchange coupling in FM overlayer at room temperature. We show that the G layer magnetically decouples the FM metals. - Highlights: • The magnetic coupling between ferromagnets mediated by graphene is studied. • To this end, the linear dichroic effect in 3p photoemission lines is employed. • For selected junctions no magnetic coupling is attained through graphene. • Graphene inhibits the magnetic alignment that normally occurs between ferromagnets.

  10. Solution-processed organic tandem solar cells with embedded optical spacers

    NARCIS (Netherlands)

    Hadipour, Afshin; de Boer, Bert; Blom, Paul W. M.

    2007-01-01

    We demonstrate a solution-processed polymer tandem solar cell in which the two photoactive single cells are separated by an optical spacer. The use of an optical spacer allows for an independent optimization of both the electronic and optical properties of the tandem cell. The optical transmission

  11. Single electron transistor with P-type sidewall spacer gates.

    Science.gov (United States)

    Lee, Jung Han; Li, Dong Hua; Lee, Joung-Eob; Kang, Kwon-Chil; Kim, Kyungwan; Park, Byung-Gook

    2011-07-01

    A single-electron transistor (SET) is one of the promising solutions to overcome the scaling limit of the Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET). Up to now, various kinds of SETs are being proposed and SETs with a dual gate (DG) structure using an electrical potential barrier have been demonstrated for room temperature operation. To operate DG-SETs, however, extra bias of side gates is necessary. It causes new problems that the electrode for side gates and the extra bias for electrical barrier increase the complexity in circuit design and operation power consumption, respectively. For the reason, a new mechanism using work function (WF) difference is applied to operate a SET at room temperature by three electrodes. Its structure consists of an undoped active region, a control gate, n-doped source/drain electrodes, and metal/silicide or p-type silicon side gates, and a SET with metal/silicide gates or p-type silicon gates forms tunnel barriers induced by work function between an undoped channel and grounded side gates. Via simulation, the effectiveness of the new mechanism is confirmed through various silicide materials that have different WF values. Furthermore, by considering the realistic conditions of the fabrication process, SET with p-type sidewall spacer gates was designed, and its brief fabrication process was introduced. The characteristics of its electrical barrier and the controllability of its control gate were also confirmed via simulation. Finally, a single-hole transistor with n-type sidewall spacer gates was designed.

  12. Empirical singular vectors of baroclinic flows deduced from experimental data of a differentially heated rotating annulus

    Directory of Open Access Journals (Sweden)

    Michael Hoff

    2015-01-01

    Full Text Available Instability is related to exponentially growing eigenmodes. Interestingly, when finite time intervals are considered, growth rates of certain initial perturbations can exceed the growth rates of the most unstable modes. Moreover, even when all modes are damped, such particular initial perturbations can still grow during finite time intervals. The perturbations with the largest growth rates are called singular vectors (SVs or optimal perturbations. They not only play an important role in atmospheric ensemble predictions, but also for the theory of instability and turbulence. Starting point for a classical SV-analysis is a linear dynamical system with a known system matrix. In contrast to this traditional approach, measured data are used here to estimate the linear propagator. For this estimation, a method is applied that uses the covariances of the measured time series to find the principal oscillation patterns (POPs that are the empirically estimated linear eigenmodes of the system. By using the singular value decomposition (SVD, we can estimate the modes of maximal growth of the propagator which are thus the empirically estimated SVs. These modes can be understood as a superposition of POPs that form a complete but in general non-orthogonal basis. The data used, originate from a differentially heated rotating annulus laboratory experiment. This experiment is an analogue of the earth's atmosphere and is used to study the development of baroclinic waves in a well controlled and reproducible way without the need of numerical approximations. Baroclinic waves form the background for many studies on SV growth and it is thus straight forward to apply the technique of empirical SV estimation to these laboratory data. To test the method of SV estimation, we use a quasi-geostrophic barotropic model and compare the known SVs from that model with SVs estimated from a surrogate data set that was generated with the help of the exact model propagator and some

  13. Pros and cons of symmetrical dual-k spacer technology in hybrid FinFETs

    Science.gov (United States)

    Pradhan, K. P.; Andrade, M. G. C.; Sahu, P. K.

    2016-12-01

    The symmetrical dual-k spacer technology in hybrid FinFETs has been widely explored for better electrostatic control of the fin-based devices in nanoscale region. Since, high-k tangible spacer materials are broadly became a matter of study due to their better immunity to the short channel effects (SCEs) in nano devices. However, the only cause that restricts the circuit designers from using high-k spacer is the unreasonable increasing fringing capacitances. This work quantitatively analyzed the benefits and drawbacks of considering two different dielectric spacer materials symmetrically in either sides of the channel for the hybrid device. From the demonstrated results, the inclusion of high-k spacer predicts an effective reduction in off-state leakage along with an improvement in drive current. However, these devices have paid the cost in terms of a high total gate-to-gate capacitance (Cgg) that consequently results poor cutoff frequency (fT) and delay.

  14. LES of turbulent flow in a concentric annulus with rotating outer wall

    International Nuclear Information System (INIS)

    Hadžiabdić, M.; Hanjalić, K.; Mullyadzhanov, R.

    2013-01-01

    Highlights: • High rotation up to N = 2 dampens progressively the turbulence near the rotating outer wall. • At 2 2.8, while tending to laminarize, the flow exhibits distinct Taylor-Couette vortical rolls. -- Abstract: Fully-developed turbulent flow in a concentric annulus, r 1 /r 2 = 0.5, Re h = 12,500, with the outer wall rotating at a range of rotation rates N = U θ,wall /U b from 0.5 up to 4 is studied by large-eddy simulations. The focus is on the effects of moderate to very high rotation rates on the mean flow, turbulence statistics and eddy structure. For N up to ∼2, an increase in the rotation rate dampens progressively the turbulence near the rotating outer wall, while affecting only mildly the inner-wall region. At higher rotation rates this trend is reversed: for N = 2.8 close to the inner wall turbulence is dramatically reduced while the outer wall region remains turbulent with discernible helical vortices as the dominant turbulent structure. The turbulence parameters and eddy structures differ significantly for N = 2 and 2.8. This switch is attributed to the centrifuged turbulence (generated near the inner wall) prevailing over the axial inertial force as well as over the counteracting laminarizing effects of the rotating outer wall. At still higher rotation, N = 4, the flow gets laminarized but with distinct spiralling vortices akin to the Taylor–Couette rolls found between the two counter-rotating cylinders without axial flow, which is the limiting case when N approaches to infinity. The ratio of the centrifugal to axial inertial forces, Ta/Re 2 ∝ N 2 (where Ta is the Taylor number) is considered as a possible criterion for defining the conditions for the above regime change

  15. Human annulus fibrosus material properties from biaxial testing and constitutive modeling are altered with degeneration.

    Science.gov (United States)

    O'Connell, Grace D; Sen, Sounok; Elliott, Dawn M

    2012-03-01

    The annulus fibrosus (AF) of the intervertebral disk undergoes large and multidirectional stresses and strains. Uniaxial tensile tests are limited for measuring AF material properties, because freely contracting edges can prevent fiber stretch and are not representative of in situ boundary conditions. The objectives of this study were to measure human AF biaxial tensile mechanics and to apply and validate a constitutive model to determine material properties. Biaxial tensile tests were performed on samples oriented along the circumferential-axial and the radial-axial directions. Data were fit to a structurally motivated anisotropic hyperelastic model composed of isotropic extra-fibrillar matrix, nonlinear fibers, and fiber-matrix interactions (FMI) normal to the fibers. The validated model was used to simulate shear and uniaxial tensile behavior, to investigate AF structure-function, and to quantify the effect of degeneration. The biaxial stress-strain response was described well by the model (R (2) > 0.9). The model showed that the parameters for fiber nonlinearity and the normal FMI correlated with degeneration, resulting in an elongated toe-region and lower stiffness with degeneration. The model simulations in shear and uniaxial tension successfully matched previously published circumferential direction Young's modulus, provided an explanation for the low values in previously published axial direction Young's modulus, and was able to simulate shear mechanics. The normal FMI were important contributors to stress and changed with degeneration, therefore, their microstructural and compositional source should be investigated. Finally, the biaxial mechanical data and constitutive model can be incorporated into a disk finite element model to provide improved quantification of disk mechanics.

  16. The Safe Removal of Frozen Air from the Annulus of an LH2 Storage Tank

    Science.gov (United States)

    Krenn, A.; Starr, S.; Youngquist, R.; Nurge, M.; Sass, J.; Fesmire, J.; Cariker, C.; Bhattacharya, A.

    2015-01-01

    Large Liquid Hydrogen (LH2) storage tanks are vital infrastructure for NASA. Eventually, air may leak into the evacuated and perlite filled annular region of these tanks. Although the vacuum level is monitored in this region, the extremely cold temperature causes all but the helium and neon constituents of air to freeze. A small, often unnoticeable pressure rise is the result. As the leak persists, the quantity of frozen air increases, as does the thermal conductivity of the insulation system. Consequently, a notable increase in commodity boil-off is often the first indicator of an air leak. Severe damage can result from normal draining of the tank. The warming air will sublimate which will cause a pressure rise in the annulus. When the pressure increases above the triple point, the frozen air will begin to melt and migrate downward. Collection of liquid air on the carbon steel outer shell may chill it below its ductility range, resulting in fracture. In order to avoid a structural failure, as described above, a method for the safe removal of frozen air is needed. A thermal model of the storage tank has been created using SINDA/FLUINT modeling software. Experimental work is progressing in an attempt to characterize the thermal conductivity of a perlite/frozen nitrogen mixture. A statistical mechanics model is being developed in parallel for comparison to experimental work. The thermal model will be updated using the experimental/statistical mechanical data, and used to simulate potential removal scenarios. This paper will address methodologies and analysis techniques for evaluation of two proposed air removal methods.

  17. Influence of vertical stratification on motion in a differentially heated rotating annulus

    Science.gov (United States)

    Boubnov, B. M.; Golitsyn, G. S.

    Understanding the influence of vertical stratification on large scale motions is of prime geophysical interest for both the stable and unstable cases. Here we present a generalization of the Lorenz (1962) model which includes externally imposed stratifications of either sign. Various flow regimes are determined, according to the values of the thermal Rossby number RoT the nondimensional rotation rate and the ratio of temperature differences in the vertical, , and horizontal directions, T. It is found that the stability curve in the RoT,R plane, while preserving its general shape which was found by Hide (1953,1969) for T=0, moves towards the lower right with increasing T>0, other conditions being equal, and to the upper left for the slightly unstable case. The curve separates the Hadley axisymmetrical regimes from the Rossby wave regimes. Introduction of a bulk Richardson number helps to separate regular and irregular wave regimes for the case of unstable stratification. Laboratory experiments with a differentially heated (both horizontally and vertically) rotating annulus confirm qualitatively all the main conclusions of the theoretical analysis for a broad range of the parameter space in which the experiments were performed. The results obtained here may also explain the damping of cyclones in the Martian atmosphere after the onset of global dust storms (Ryan and Henry, 1979) and the attenuation of synoptic activity in numerical experiments modelling the atmospheric consequences of nuclear war (Schneider, 1985). The results are also related to the nature of the stable stratification of the majority of planetary atmospheres even for conditions when the prime radiative equilibrium temperature gradient is unstable.

  18. Intraoperative molds to create an articulating spacer for the infected knee arthroplasty.

    Science.gov (United States)

    Van Thiel, Geoffrey S; Berend, Keith R; Klein, Gregg R; Gordon, Alexander C; Lombardi, Adolph V; Della Valle, Craig J

    2011-04-01

    Chronic infections in TKA have been traditionally treated with a two-stage protocol incorporating a temporary antibiotic-loaded cement spacer. The use of a static as opposed to an articulating spacer is controversial. Some surgeons believe a static spacer results in a higher rate of infection eradication, whereas others believe an articulating spacer provides equivalent rates of infection control with improved function between stages and the potential for better eventual range of motion. We determined the rates of infection control and postoperative function for an articulating all-cement antibiotic spacer fashioned intraoperatively from prefabricated silicone molds. We retrospectively reviewed 60 patients with an infected TKA using the same cement-on-cement articulating spacer. A minimum of 4 g antibiotic per package of cement was used when making the spacer. Complications and pre- and postoperative knee flexion, extension, and Knee Society scores were recorded. Bone loss associated with the spacer was determined radiographically and by intraoperative inspection of the bony surfaces at the second stage. Minimum followup was 24 months (mean, 35 months; range, 24-51 months). Seven patients (12%) became reinfected, four with an organism different from that identified at the index resection arthroplasty. One spacer femoral component broke between stages but did not require any specific treatment. We identified no bone loss between stages and no complications related to the cement-on-cement articulation. The mean pretreatment Knee Society scores of 53 improved to 79. The mean preoperative flexion of 90.6º improved to 101.3º at final followup. An articulating antibiotic spacer was associated with control of a deep periprosthetic infection in 88% of patients while allowing range of motion between stages. Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

  19. BWR fuel assembly with improved spacer and fuel bundle design for enhanced thermal-hydraulic performance

    International Nuclear Information System (INIS)

    Mildrum, C.M.; Taleyarkhan, R.P.

    1987-01-01

    In a fuel assembly having a bundle of elongated fuel rods disposed in side-by-side relationship so as to form an array of spaced fuel rods, an outer tubular flow channel surrounding the fuel rods so as to direct flow of coolant/moderator fluid along the fuel rods, a hollow water cross extending centrally through and interconnected with the outer flow channel so as to divide the channel into separate compartments and the bundle of fuelrods into a plurality of mini-bundles thereof being disposed in the compartments, and spacers axially displaced along the fuel rods in each of the mini-bundles thereof. Each spacer is composed of inner and outer means which together define spacer cells at corner, side and interior locations of the spacer and have respective protrusions formed thereon which extend into cells so as to maintain the fuel rods received through the spacer cells in laterally spaced relationships. The improvement is described which comprises: (a) a generally uniform poison coating within at least a majority of the fuel rods; (b) a predetermined pattern of fuel enrichment with respect to the fuel rods of each mini-bundle thereof which together with the uniform poison coating within the fuel rods ensures that the packing powers of the fuel rods in the corner and side cells of the spacers are less than the peaking power of a leading one of the fuel rods in the interior cells of the spacers; and (c) each of the fuel rods being received through the cells of each spacer having a diametric size smaller than that of each of the fuel rods received through the side and interior cells of each spacer, the diametric sizes of each of the fuel rods received through the side and interior cells of each spacer being generally equal

  20. Polyetheretherketone (PEEK) Spacers for Anterior Cervical Fusion: A Retrospective Comparative Effectiveness Clinical Trial.

    Science.gov (United States)

    Lemcke, Johannes; Al-Zain, Ferass; Meier, Ullrich; Suess, Olaf

    2011-01-01

    Anterior cervical decompression and fusion (ACDF) is the standard surgical treatment for radiculopathy and myelopathy. Polyetheretherketone (PEEK) has an elasticity similar to bone and thus appears well suited for use as the implant in ACDF procedures. The aim of this study is to examine the clinical and radiographic outcome of patients treated with standing alone PEEK spacers without bone morphogenic protein (BMP) or plating and to examine the influence of the different design of the two spacers on the rate of subsidence and dislocation. This retrospective comparative study reviewed 335 patients treated by ACDF in a specialized urban hospital for radiculopathy or myelopathy due to degenerative pathologies. The Intromed PEEK spacer was used in 181 patients from 3/2002 to 11/2004, and the AMT SHELL spacer was implanted in 154 patients from 4/2004 to 12/2007. The follow-up rate was 100% at three months post-op and 82.7% (277 patients) at one year. The patients were assessed with the Japanese Orthopedic Association (JOA) questionnaire and radiographically. At the one-year follow-up there were 118/277 patients with an excellent clinical outcome on the JOA, 112/277 with a good outcome, 20/277 with a fair outcome, and 27/277 with a poor outcome. Subsidence was observed in 13.3% of patients with the Intromed spacer vs 8.4% of the patients with the AMT SHELL. Dislocation of the spacer was observed in 10 of the 181 patients with Intromed spacers but in none of the 154 patients with Shell spacers. The study demonstrates that ACDF with standing alone PEEK cages leads to excellent and good clinical outcomes. The differences we observed in the subsidence rate between the two spacers were not significant and cannot be related to a single design feature of the spacers.

  1. Impact of underlap spacer region variation on electrostatic and analog performance of symmetrical high-k SOI FinFET at 20 nm channel length

    Science.gov (United States)

    Jain, Neeraj; Raj, Balwinder

    2017-12-01

    Continued scaling of CMOS technology to achieve high performance and low power consumption of semiconductor devices in the complex integrated circuits faces the degradation in terms of electrostatic integrity, short channel effects (SCEs), leakage currents, device variability and reliability etc. Nowadays, multigate structure has become the promising candidate to overcome these problems. SOI FinFET is one of the best multigate structures that has gained importance in all electronic design automation (EDA) industries due to its improved short channel effects (SCEs), because of its more effective gate-controlling capabilities. In this paper, our aim is to explore the sensitivity of underlap spacer region variation on the performance of SOI FinFET at 20 nm channel length. Electric field modulation is analyzed with spacer length variation and electrostatic performance is evaluated in terms of performance parameter like electron mobility, electric field, electric potential, sub-threshold slope (SS), ON current (I on), OFF current (I off) and I on/I off ratio. The potential benefits of SOI FinFET at drain-to-source voltage, V DS = 0.05 V and V DS = 0.7 V towards analog and RF design is also evaluated in terms of intrinsic gain (A V), output conductance (g d), trans-conductance (g m), gate capacitance (C gg), and cut-off frequency (f T = g m/2πC gg) with spacer region variations.

  2. Abundant and diverse clustered regularly interspaced short palindromic repeat spacers in Clostridium difficile strains and prophages target multiple phage types within this pathogen.

    Science.gov (United States)

    Hargreaves, Katherine R; Flores, Cesar O; Lawley, Trevor D; Clokie, Martha R J

    2014-08-26

    Clostridium difficile is an important human-pathogenic bacterium causing antibiotic-associated nosocomial infections worldwide. Mobile genetic elements and bacteriophages have helped shape C. difficile genome evolution. In many bacteria, phage infection may be controlled by a form of bacterial immunity called the clustered regularly interspaced short palindromic repeats/CRISPR-associated (CRISPR/Cas) system. This uses acquired short nucleotide sequences (spacers) to target homologous sequences (protospacers) in phage genomes. C. difficile carries multiple CRISPR arrays, and in this paper we examine the relationships between the host- and phage-carried elements of the system. We detected multiple matches between spacers and regions in 31 C. difficile phage and prophage genomes. A subset of the spacers was located in prophage-carried CRISPR arrays. The CRISPR spacer profiles generated suggest that related phages would have similar host ranges. Furthermore, we show that C. difficile strains of the same ribotype could either have similar or divergent CRISPR contents. Both synonymous and nonsynonymous mutations in the protospacer sequences were identified, as well as differences in the protospacer adjacent motif (PAM), which could explain how phages escape this system. This paper illustrates how the distribution and diversity of CRISPR spacers in C. difficile, and its prophages, could modulate phage predation for this pathogen and impact upon its evolution and pathogenicity. Clostridium difficile is a significant bacterial human pathogen which undergoes continual genome evolution, resulting in the emergence of new virulent strains. Phages are major facilitators of genome evolution in other bacterial species, and we use sequence analysis-based approaches in order to examine whether the CRISPR/Cas system could control these interactions across divergent C. difficile strains. The presence of spacer sequences in prophages that are homologous to phage genomes raises an

  3. In vitro performance of three combinations of spacers and pressurized metered dose inhalers for treatment in children

    DEFF Research Database (Denmark)

    Berg, E; Madsen, J; Bisgaard, H

    1998-01-01

    The performance of pressurized metered dose inhalers (pMDIs) and spacers in correct dose recommendations is important, but limited information on dose delivery and fine-particle dose from different combinations of spacers and pMDIs is available. In this study, three combinations of spacers and p...... and spacers, with the NebuChamber giving the highest dose, both as delivered dose and in droplets account for these differences....

  4. A Study on Cell Size of Irradiated Spacer Grid for PWR Fuel

    International Nuclear Information System (INIS)

    Jin, Y. G.; Kim, G. S.; Ryu, W. S. and others

    2014-01-01

    The spacer grids supporting the fuel rods absorb vibration impacts due to the reactor coolant flow, and grid spring force decreases under irradiation. This reduction of contact force might cause grid-to-rod fretting wear. The fretting failure of the fuel rod is one of the recent significant issues in the nuclear industry from an economical as well as a safety concern. Thus, it is important to understand the characteristics of cell spring behavior and the change in size of grid cells for an irradiated spacer grid. In the present study, the dimensional measurement of a spacer grid was conducted to investigate the cell size of an irradiated spacer grid in a hot cell at IMEF (Irradiated Materials Examination Facility) of KAERI. To evaluate the fretting wear performance of an irradiated spacer grid, hot cell tests were carried out at IMEF of KAERI. Hot cell examinations include dimensional measurements for the irradiated spacer grid. The change of cell sizes was dependent on the direction of the spacer grids, leading to significant gap variations. It was found that the change in size of the cell springs due to irradiation-induced stress relaxation and creep during the fuel residency in the reactor core affect the contact behavior between the fuel rod and the cell spring

  5. Evaluation of spacer grid spring characteristics by means of physical tests and numerical simulation

    Energy Technology Data Exchange (ETDEWEB)

    Schettino, Carlos Frederico Mattos, E-mail: carlosschettino@inb.gov.br [Industrias Nucleares do Brasil (INB), Resende, RJ (Brazil)

    2017-11-01

    Among all fuel assemblies' components, the spacer grids play an important structural role during the energy generation process, mainly due for its primary functional requirement, that is, to provide fuel rod support. The present work aims to evaluate the spring characteristics of a specific spacer grid design used in a PWR fuel assembly type 16 x 16. These spring characteristics comprises the load versus deflection capability and its spring rate, which are very important, and also mandatory, to be correctly established in order to preclude spacer grid spring and fuel rod cladding fretting during operation, as well as prevent an excessive fuel rod buckling. This study includes physical tests and numerical simulation. The tests were performed on an adapted load cell mechanical device, using as a specimen a single strap of the spacer grid. Three numerical models were prepared using the Finite Element Method, with the support of the commercial code ANSYS. One model was built to validate the simulation according to the performed physical test, the others were built inserting a gradient of temperature (Beginning Of Life hot condition) and to evaluate the spacer grid spring characteristics in End Of Life condition. The obtained results from physical test and numerical model have shown a good agreement between them, therefore validating the simulation. The obtained results from numerical models make available information regarding the spacer grid design purpose, such as the behavior of the fuel rod cladding support during operation. Therewith, these evaluations could be useful to improve the spacer grid design. (author)

  6. Efficient double-emitting layer inverted organic light-emitting devices with different spacer layers

    Science.gov (United States)

    Nie, Qu-yang; Zhang, Fang-hui

    2017-09-01

    Double-emitting layer inverted organic light-emitting devices (IOLEDs) with different spacer layers were investigated, where 2,20,7,70-tetrakis(carbazol-9-yl)-9,9-spirobifluorene (CBP), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-diphenyl-1,10-phenanthroline (Bphen) and 4,40,400-tris(N-carbazolyl)-triphenylamine (TCTA) were used as spacer layers, respectively, and GIr1 and R-4b were used as green and red guest phosphorescent materials, respectively. The results show that the device with BCP spacer layer has the best performance. The maximum current efficiency of the BCP spacer layer device reaches up to 24.15 cd·A-1 when the current density is 3.99 mA·cm-2, which is 1.23 times bigger than that of the CBP spacer layer device. The performance is better than that of corresponding conventional device observably. The color coordinate of the device with BCP spacer layer only changes from (0.625 1, 0.368 0) to (0.599 5, 0.392 8) when the driving voltage increases from 6 V to 10 V, so it shows good stability in color coordinate, which is due to the adoption of the co-doping evaporation method for cladding luminous layer and the effective restriction of spacer layer to carriers in emitting layer.

  7. Aortic annulus eccentricity before and after transcatheter aortic valve implantation: Comparison of balloon-expandable and self-expanding prostheses

    Energy Technology Data Exchange (ETDEWEB)

    Schuhbaeck, Annika, E-mail: annika.schuhbaeck@uk-erlangen.de [Department of Cardiology, University of Erlangen, Erlangen (Germany); Weingartner, Christina [Department of Cardiology, University of Gießen, Giessen (Germany); Arnold, Martin; Schmid, Jasmin; Pflederer, Tobias; Marwan, Mohamed [Department of Cardiology, University of Erlangen, Erlangen (Germany); Rixe, Johannes; Nef, Holger [Department of Cardiology, University of Gießen, Giessen (Germany); Schneider, Christian [Department of Radiology, University of Gießen, Giessen (Germany); Lell, Michael; Uder, Michael [Department of Radiology, University of Erlangen, Erlangen (Germany); Ensminger, Stephan [Department of Thoracic and Cardiovascular Surgery, Heart and Diabetes Center NRW, Ruhr-University Bochum, Bad Oeynhausen (Germany); Feyrer, Richard; Weyand, Michael [Department of Cardiothoracic Surgery, University of Erlangen, Erlangen (Germany); Achenbach, Stephan [Department of Cardiology, University of Erlangen, Erlangen (Germany)

    2015-07-15

    Highlights: • Post-implant geometry of catheter-based aortic valve prostheses is influenced by aortic valve calcification. • Balloon-expandable prostheses are more circular as compared to self-expanding prostheses. • The impact of post-implant geometry on valve function needs to be investigated. - Abstract: Introduction: The geometry of the aortic annulus and implanted transcatheter aortic valve prosthesis might influence valve function. We investigated the influence of valve type and aortic valve calcification on post-implant geometry of catheter-based aortic valve prostheses. Methods: Eighty consecutive patients with severe aortic valve stenosis (mean age 82 ± 6 years) underwent computed tomography before and after TAVI. Aortic annulus diameters were determined. Influence of prosthesis type and degree of aortic valve calcification on post-implant eccentricity were analysed. Results: Aortic annulus eccentricity was reduced in patients after TAVI (0.21 ± 0.06 vs. 0.08 ± 0.06, p < 0.0001). Post-TAVI eccentricity was significantly lower in 65 patients following implantation of a balloon-expandable prosthesis as compared to 15 patients who received a self-expanding prosthesis (0.06 ± 0.05 vs. 0.15 ± 0.07, p < 0.0001), even though the extent of aortic valve calcification was not different. After TAVI, patients with a higher calcium amount retained a significantly higher eccentricity compared to patients with lower amounts of calcium. Conclusions: Patients undergoing TAVI with a balloon-expandable prosthesis show a more circular shape of the implanted prosthesis as compared to patients with a self-expanding prosthesis. Eccentricity of the deployed prosthesis is affected by the extent of aortic valve calcification.

  8. Aortic annulus eccentricity before and after transcatheter aortic valve implantation: Comparison of balloon-expandable and self-expanding prostheses

    International Nuclear Information System (INIS)

    Schuhbaeck, Annika; Weingartner, Christina; Arnold, Martin; Schmid, Jasmin; Pflederer, Tobias; Marwan, Mohamed; Rixe, Johannes; Nef, Holger; Schneider, Christian; Lell, Michael; Uder, Michael; Ensminger, Stephan; Feyrer, Richard; Weyand, Michael; Achenbach, Stephan

    2015-01-01

    Highlights: • Post-implant geometry of catheter-based aortic valve prostheses is influenced by aortic valve calcification. • Balloon-expandable prostheses are more circular as compared to self-expanding prostheses. • The impact of post-implant geometry on valve function needs to be investigated. - Abstract: Introduction: The geometry of the aortic annulus and implanted transcatheter aortic valve prosthesis might influence valve function. We investigated the influence of valve type and aortic valve calcification on post-implant geometry of catheter-based aortic valve prostheses. Methods: Eighty consecutive patients with severe aortic valve stenosis (mean age 82 ± 6 years) underwent computed tomography before and after TAVI. Aortic annulus diameters were determined. Influence of prosthesis type and degree of aortic valve calcification on post-implant eccentricity were analysed. Results: Aortic annulus eccentricity was reduced in patients after TAVI (0.21 ± 0.06 vs. 0.08 ± 0.06, p < 0.0001). Post-TAVI eccentricity was significantly lower in 65 patients following implantation of a balloon-expandable prosthesis as compared to 15 patients who received a self-expanding prosthesis (0.06 ± 0.05 vs. 0.15 ± 0.07, p < 0.0001), even though the extent of aortic valve calcification was not different. After TAVI, patients with a higher calcium amount retained a significantly higher eccentricity compared to patients with lower amounts of calcium. Conclusions: Patients undergoing TAVI with a balloon-expandable prosthesis show a more circular shape of the implanted prosthesis as compared to patients with a self-expanding prosthesis. Eccentricity of the deployed prosthesis is affected by the extent of aortic valve calcification

  9. Characterization of feed channel spacer performance using geometries obtained by X-ray computed tomography

    KAUST Repository

    Haaksman, Viktor A.

    2016-09-09

    Spiral-wound membrane modules used in water treatment for water reuse and desalination make use of spacer meshes for keeping the membrane leaves apart and for enhancing the mass transfer. Computational fluid dynamics (CFD) has gained importance in the design of new spacers with optimized hydrodynamic characteristics, but this requires a precise description of the spacer geometry. This study developed a method to obtain accurate three-dimensional (3-D) geometry representations for any given spacer design from X-ray computed tomography (CT) scans. The method revealed that the filaments of industrial spacers have a highly variable cross-section size and shape, which impact the flow characteristics in the feed channel. The pressure drop and friction factors were calculated from numerical simulations on five commercially available feed spacers used in practice. Model solutions compared well to experimental data measured using a flow cell for average velocities up to 0.2 m/s, as used in industrial reverse osmosis and nanofiltration membrane operations. A newly-proposed spacer geometry with alternating strand thickness was tested, which was found to yield a lower pressure drop while being highly efficient in converting the pumping power into membrane shear. Numerical model solutions using CFD with geometries from CT scans were closer to measurements than those obtained using the traditional circular cross-section strand simplification, indicating that CT scans are very well suitable to approximate real feed spacer geometries. By providing detailed insight on the spacer filament shape, CT scans allow better quantification of local distribution of velocity and shear, possibly leading to more accurate estimations of fouling and concentration polarization. © 2016 Elsevier B.V.

  10. Steady natural convection heat transfer experiments in a horizontal annulus for the United States Spent Fuel Shipping Cask Technology Program

    International Nuclear Information System (INIS)

    Boyd, R.D.

    1981-04-01

    This experimental study deals with the measurement of the heat transfer across a horizontal annulus which is formed by an inner hexagonal cylinder and an outer concentric circular cylinder. The geometry simulates, in two dimensions, a liquid metal fast breeder reactor radioactive fuel subassembly inside a shipping container. This geometry is also similar to a radioactive fuel pin inside a horizontal reactor subassembly. The objective of the experiments is to measure the local and mean heat transfer at the surface of the inner hexagonal cylinder

  11. Experimental investigation on turbulent heat transfer in liquid metal along a heated rod in a vertical annulus

    International Nuclear Information System (INIS)

    Loges, A.; Baumann, T.; Marocco, L.; Wetzel, T.; Stieglitz, R.

    2011-01-01

    In a couple of European research centres, Accelerator Driven Systems (ADS) are investigated for the transmutation of radioactive waste. In one of these concept lead bismuth eutectic (LBE) is applied as coolant. In different experiments covering forced and mixed convection in turbulent LBE flow in a concentric annulus the local velocity and temperature fields were investigated at prototypical power levels and dimensions. Local heat transfer properties were extracted and compared with literature data. A new empirical correlation for the Nusselt number for the thermal entry region for turbulent forced convection in liquid metals is introduced and the transition from forced to mixed convection in LBE is characterized. (author)

  12. Modulation of porphyrin photoluminescence by nanoscale spacers on silicon substrates

    International Nuclear Information System (INIS)

    Fang, Y.C.; Zhang, Y.; Gao, H.Y.; Chen, L.G.; Gao, B.; He, W.Z.; Meng, Q.S.; Zhang, C.; Dong, Z.C.

    2013-01-01

    We investigate photoluminescence (PL) properties of quasi-monolayered tetraphenyl porphyrin (TPP) molecules on silicon substrates modulated by three different nanoscale spacers: native oxide layer (NOL), hydrogen (H)-passivated layer, and Ag nanoparticle (AgNP) thin film, respectively. In comparison with the PL intensity from the TPP molecules on the NOL-covered silicon, the fluorescence intensity from the molecules on the AgNP-covered surface was greatly enhanced while that for the H-passivated surface was found dramatically suppressed. Time-resolved fluorescence spectra indicated shortened lifetimes for TPP molecules in both cases, but the decay kinetics is believed to be different. The suppressed emission for the H-passivated sample was attributed to the weaker decoupling effect of the monolayer of hydrogen atoms as compared to the NOL, leading to increased nonradiative decay rate; whereas the enhanced fluorescence with shortened lifetime for the AgNP-covered sample is attributed not only to the resonant excitation by local surface plasmons, but also to the increased radiative decay rate originating from the emission enhancement in plasmonic “hot-spots”.

  13. Modulation of porphyrin photoluminescence by nanoscale spacers on silicon substrates

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Y.C. [Department of Vacuum Science and Engineering, Hefei University of Technology, Hefei, Anhui, 230009 (China); HFNL, University of Science and Technology of China, Hefei, Anhui, 230026 (China); Zhang, Y.; Gao, H.Y.; Chen, L.G.; Gao, B.; He, W.Z.; Meng, Q.S.; Zhang, C. [HFNL, University of Science and Technology of China, Hefei, Anhui, 230026 (China); Dong, Z.C., E-mail: zcdong@ustc.edu.cn [HFNL, University of Science and Technology of China, Hefei, Anhui, 230026 (China)

    2013-11-15

    We investigate photoluminescence (PL) properties of quasi-monolayered tetraphenyl porphyrin (TPP) molecules on silicon substrates modulated by three different nanoscale spacers: native oxide layer (NOL), hydrogen (H)-passivated layer, and Ag nanoparticle (AgNP) thin film, respectively. In comparison with the PL intensity from the TPP molecules on the NOL-covered silicon, the fluorescence intensity from the molecules on the AgNP-covered surface was greatly enhanced while that for the H-passivated surface was found dramatically suppressed. Time-resolved fluorescence spectra indicated shortened lifetimes for TPP molecules in both cases, but the decay kinetics is believed to be different. The suppressed emission for the H-passivated sample was attributed to the weaker decoupling effect of the monolayer of hydrogen atoms as compared to the NOL, leading to increased nonradiative decay rate; whereas the enhanced fluorescence with shortened lifetime for the AgNP-covered sample is attributed not only to the resonant excitation by local surface plasmons, but also to the increased radiative decay rate originating from the emission enhancement in plasmonic “hot-spots”.

  14. Mobile Learning Using Mobile Phones

    Science.gov (United States)

    Vicente, Paula

    2013-01-01

    The participation in mobile learning programs is conditioned by having/using mobile communication technology. Those who do not have or use such technology cannot participate in mobile learning programs. This study evaluates who are the most likely participants of mobile learning programs by examining the demographic profile and mobile phone usage…

  15. [Interspinous spacers and disc herniation. Geomorphometric and clinical study of 71 cases treated by L4-L5 microdiscectomy associated to spacer placement].

    Science.gov (United States)

    Aso Escario, José; Aso Vizán, Alberto; Martínez Quiñones, José Vicente; Consolini, Fabian; Martín Gallego, Álvaro; Arregui Calvo, Ricardo

    2015-01-01

    A controversial indication of interspinous spacers is their use as a complement to discectomy. At the present time, there is no solid clinical evidence of effectiveness of that association, which might result from variability in spacer positioning, restricting its correct biomechanical actions. In this study our goal was to identify and analyse the variability in the placement of an interspinous spacer, and to investigate its relationship with the clinical results. We performed a retrospective study on X-ray films from 71 patients suffering from disc herniation in L4-L5 who underwent surgery in our hospital, consisting of: microdiscectomy and biomed interspinous spacer implantation. The geomorphometric techniques used to analyse the data were procrustes superimposition and principal components analysis. We compared the clinical results (using the Herron and Turner scale), segmental lordosis and surgical distraction with the geomorphometric parameters. Significant morphological variability was found in the implant position showing cephalo-caudal translation and clockwise-counterclockwise rotations. This variability did not correlate with clinical results. A relationship with anatomical features (lordosis) and additional surgical distraction was identified. A different morphology of implant-segment configuration was identified in cases with recurrence of disc herniation. Geometric morphometrics allowed identifying high variability in the final placement of interspinous spacers. Nevertheless, it seems not to be related to the clinical outcome, depending rather on the degree of lordosis and distraction. Some differences in segment-implant morphology were identified in cases with recurrences. To assess the effectiveness of spacers, larger studies including morphological and clinical variables are required. Copyright © 2013 Sociedad Española de Neurocirugía. Published by Elsevier España. All rights reserved.

  16. Effects of grid spacer with mixing vane on entrainments and depositions in two-phase annular flows

    Directory of Open Access Journals (Sweden)

    Akimaro Kawahara

    2015-06-01

    Full Text Available The effects of mixing vanes (MVs attached to a grid spacer on the characteristics of air–water annular flows were experimentally investigated. To know the effects, a grid spacer with or without MV was inserted in a vertical circular pipe of 16-mm internal diameter. For three cases (i.e., no spacer, spacer without MV, and spacer with MV, the liquid film thickness, liquid entrainment fraction, and deposition rate were measured by the constant current method, single liquid film extraction method, and double liquid film extraction method, respectively. The MVs significantly promote the re-deposition of liquid droplets in the gas core flow into the liquid film on the channel walls. The deposition mass transfer coefficient is three times higher for the spacer with MV than for the spacer without MV, even for cases 0.3-m downstream from the spacer. The liquid film thickness becomes thicker upstream and downstream for the spacer with MV, compared with the thickness for the spacer without MV and for the case with no spacer.

  17. Non linear fe analysis on the static buckling behavior of the spacer grid structures

    International Nuclear Information System (INIS)

    Song, K.N.; Yoon, K.H.

    2001-01-01

    In this study considered is the static buckling behavior of spacer grids in the fuel assembly, which are required to have a sufficient strength against an accident like earthquake. Special attention is given to the finite element modeling of the spot-welding and the constraints between the spacer strips assembled together: it is found that a proper treatment of the constraints is critical for accurate assessment of the buckling behavior including strain localization at the point of spot welding. The buckling strength of the 17 x 17 spacer grid, which is difficult to analyze due to a large number of degrees of freedom, is estimated from analysis for the smaller models 3 x 3, 5 x 5, 7 x 7, and 9 x 9 spacer grids. (authors)

  18. Impact of a Protective Vest and Spacer Garment on Exercise-Heat Strain

    National Research Council Canada - National Science Library

    Cheuvront, Samuel N; Goodman, Daniel A; Kenefick, Robert W; Montain, Scott J; Sawka, Michael N

    2008-01-01

    ...). Volunteers wore the US Army battle dress uniform (trial B), B + protective vest (trial P), and B + P + spacer garment (trial S). Biophysical clothing properties were determined and found similar to many law enforcement, industry, and sports ensembles...

  19. A simulation methodology of spacer grid residual spring deflection for predictive and interpretative purposes

    International Nuclear Information System (INIS)

    Kim, K. T.; Kim, H. K.; Yoon, K. H.

    1994-01-01

    The in-reactor fuel rod support conditions against the fretting wear-induced damage can be evaluated by spacer grid residual spring deflection. In order to predict the spacer grid residual spring deflection as a function of burnup for various spring designs, a simulation methodology of spacer grid residual spring deflection has been developed and implemented in the GRIDFORCE program. The simulation methodology takes into account cladding creep rate, initial spring deflection, initial spring force, and spring force relaxation rate as the key parameters affecting the residual spring deflection. The simulation methodology developed in this study can be utilized as an effective tool in evaluating the capability of a newly designed spacer grid spring to prevent the fretting wear-induced damage

  20. The effect of endoskeleton on antibiotic impregnated cement spacer for treating deep hip infection

    Directory of Open Access Journals (Sweden)

    Hsu Wei-Hsiu

    2011-01-01

    Full Text Available Abstract Backgrounds A two-stage revision arthroplasty was suggested optimal treatment for deep infections in hip joint. The effect of endoskeleton of cement spacers on the interim function and infection control remains unclear. Methods From Jan. 2004 to Dec. 2007, we collected a prospective cohort of consecutive 34 patients who treated with two-stage revision total hip arthroplasty for deep infection of hip joint. In group 1, fifteen patients were treated by a novel design augmented with hip compression screw while nineteen patients were treated by traditional design in group 2. Results No fracture of cement spacer occurred in group 1 while 6 cases developed spacer failure in group 2. (p Conclusions Patients being treated for deep infection of hip joint using cement spacer augmented with stronger endoskeleton have lower pain levels and better joint function between stages.

  1. Spacer geometry and particle deposition in spiral wound membrane feed channels

    KAUST Repository

    Radu, A.I.

    2014-11-01

    Deposition of microspheres mimicking bacterial cells was studied experimentally and with a numerical model in feed spacer membrane channels, as used in spiral wound nanofiltration (NF) and reverse osmosis (RO) membrane systems. In-situ microscopic observations in membrane fouling simulators revealed formation of specific particle deposition patterns for different diamond and ladder feed spacer orientations. A three-dimensional numerical model combining fluid flow with a Lagrangian approach for particle trajectory calculations could describe very well the in-situ observations on particle deposition in flow cells. Feed spacer geometry, positioning and cross-flow velocity sensitively influenced the particle transport and deposition patterns. The deposition patterns were not influenced by permeate production. This combined experimental-modeling approach could be used for feed spacer geometry optimization studies for reduced (bio)fouling. © 2014 Elsevier Ltd.

  2. A Facile Technique to Make Articulating Spacers for Infected Total Knee Arthroplasty

    Directory of Open Access Journals (Sweden)

    Yu-Ping Su

    2009-03-01

    Conclusion: Treating infected total knee arthroplasty with these self-made articulating spacers eradicates infection effectively, improves the life quality before reimplantation and provides good final results without significant complications.

  3. Computer-Aided Design Method of Warp-Knitted Jacquard Spacer Fabrics

    Directory of Open Access Journals (Sweden)

    Li Xinxin

    2016-06-01

    Full Text Available Based on a further study on knitting and jacquard principles, this paper presents a mathematical design model to make computer-aided design of warp-knitted jacquard spacer fabrics more efficient. The mathematical model with matrix method employs three essential elements of chain notation, threading and Jacquard designing. With this model, the processing to design warp-knitted jacquard spacer fabrics with CAD software is also introduced. In this study, the sports shoes which have separated functional areas according to the feet structure and characteristics of movement are analysed. The results show the different patterns on Jacquard spacer fabrics that are seamlessly stitched with jacquard technics. The computer-aided design method of warp-knitted jacquard spacer fabrics is efficient and simple.

  4. CRISPR Spacer Arrays for Detection of Viral Signatures from Acidic Hot Springs

    Science.gov (United States)

    Snyder, J. C.; Bateson, M. M.; Suciu, D.; Young, M. J.

    2010-04-01

    Viruses are the most abundant life-like entities on the planet Earth. Using CRISPR spacer sequences, we have developed a microarray-based approach to detecting viral signatures in the acidic hot springs of Yellowstone.

  5. Annular flow in rod-bundle: Effect of spacer on disturbance waves

    Energy Technology Data Exchange (ETDEWEB)

    Pham, Son H.; Kunugi, Tomoaki

    2016-08-01

    A high-speed camera technique is used to study the effect of spacers on the disturbance waves present in annular two-phase flow within a rod-bundle geometry. Images obtained using a backlight configuration to visualize the spacer-wave interactions at the micro-scale resolution (in time and space) are discussed. This paper also presents additional images obtained using a reflected light configuration which provides new observations of the disturbance waves. These images show the separation effect caused by the spacer on the liquid film in which the size of generated liquid droplets can be controlled by the gas superficial velocity. Furthermore, the data confirm that the spacer breaks the circumferential coherent structures of the waves.

  6. Influence of the Quantity of Aortic Valve Calcium on the Agreement Between Automated 3-Dimensional Transesophageal Echocardiography and Multidetector Row Computed Tomography for Aortic Annulus Sizing.

    Science.gov (United States)

    Podlesnikar, Tomaz; Prihadi, Edgard A; van Rosendael, Philippe J; Vollema, E Mara; van der Kley, Frank; de Weger, Arend; Ajmone Marsan, Nina; Naji, Franjo; Fras, Zlatko; Bax, Jeroen J; Delgado, Victoria

    2018-01-01

    Accurate aortic annulus sizing is key for selection of appropriate transcatheter aortic valve implantation (TAVI) prosthesis size. The present study compared novel automated 3-dimensional (3D) transesophageal echocardiography (TEE) software and multidetector row computed tomography (MDCT) for aortic annulus sizing and investigated the influence of the quantity of aortic valve calcium (AVC) on the selection of TAVI prosthesis size. A total of 83 patients with severe aortic stenosis undergoing TAVI were evaluated. Maximal and minimal aortic annulus diameter, perimeter, and area were measured. AVC was assessed with computed tomography. The low and high AVC burden groups were defined according to the median AVC score. Overall, 3D TEE measurements slightly underestimated the aortic annulus dimensions as compared with MDCT (mean differences between maximum, minimum diameter, perimeter, and area: -1.7 mm, 0.5 mm, -2.7 mm, and -13 mm 2 , respectively). The agreement between 3D TEE and MDCT on aortic annulus dimensions was superior among patients with low AVC burden (AVC burden (≥3,025 arbitrary units). The interobserver variability was excellent for both methods. 3D TEE and MDCT led to the same prosthesis size selection in 88%, 95%, and 81% of patients in the total population, the low, and the high AVC burden group, respectively. In conclusion, the novel automated 3D TEE imaging software allows accurate and highly reproducible measurements of the aortic annulus dimensions and shows excellent agreement with MDCT to determine the TAVI prosthesis size, particularly in patients with low AVC burden. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  7. The effect of ammonia flow in the AlN spacer on the electrical properties of InAlN/AlN/GaN HEMT structures

    International Nuclear Information System (INIS)

    Gamarra, Piero; Lacam, Cedric; Magis, Michelle; Tordjman, Maurice; Di Forte Poisson, Marie-Antoinette

    2012-01-01

    During the past few years it has been reported that a thin AlN spacer of few nanometers needs to be inserted in InAlN/GaN high electron mobility transistors (HEMTs) to obtain high 2DEG carrier mobility. This work presents a systematic study of the effects of varying the ammonia flow in the AlN spacer of InAlN/AlN/GaN HEMTs grown by low pressure metalorganic vapour phase epitaxy (LP-MOVPE). The strain state, the surface roughness and the growth rate of AlN were found to be dependent on the V/III ratio. In addition the ammonia flow in the interlayer has a strong impact on the structural properties of the subsequent InAlN barrier layer and on the electrical properties of the structure. A sheet resistance as low as 327 Ω/□ with a sheet carrier density of 1.5 x 10 13 cm -2 has been obtained at room temperature. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. The effect of ammonia flow in the AlN spacer on the electrical properties of InAlN/AlN/GaN HEMT structures

    Energy Technology Data Exchange (ETDEWEB)

    Gamarra, Piero; Lacam, Cedric; Magis, Michelle; Tordjman, Maurice; Di Forte Poisson, Marie-Antoinette [III-V Lab., Marcussis (France)

    2012-01-15

    During the past few years it has been reported that a thin AlN spacer of few nanometers needs to be inserted in InAlN/GaN high electron mobility transistors (HEMTs) to obtain high 2DEG carrier mobility. This work presents a systematic study of the effects of varying the ammonia flow in the AlN spacer of InAlN/AlN/GaN HEMTs grown by low pressure metalorganic vapour phase epitaxy (LP-MOVPE). The strain state, the surface roughness and the growth rate of AlN were found to be dependent on the V/III ratio. In addition the ammonia flow in the interlayer has a strong impact on the structural properties of the subsequent InAlN barrier layer and on the electrical properties of the structure.istance as low as 327 {omega}/{open_square} with a sheet carrier density of 1.5 x 10{sup 13} cm{sup -2} has been obtained at room temperature. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Feasibility Study of Interactive Game Technologies to Improve Experience with Inhaler Spacer Devices in Young Children

    OpenAIRE

    Aslam, Tariq; Shakir, Savana; Murray, Clare

    2016-01-01

    IntroductionThe correct use of inhaler devices with facemasks and spacers in young children can be difficult for both children and parents, resulting in distress for both, poor adherence and ineffective drug delivery. The aim of this study was to develop and assess the utility and impact of an interactive electronic game designed to improve the experience of spacer devices in young asthmatic children.MethodsThe Respiratory Aid For Inhaler (RAFIhaler) technology consists of a smartphone mounte...

  10. Biofouling patterns in spacer filled channels: High resolution imaging for characterization of heterogeneous biofilms

    KAUST Repository

    Staal, Marc

    2017-08-15

    Biofilms develop in heterogeneous patterns at a µm scale up to a cm scale, and patterns become more pronounced when biofilms develop under complex hydrodynamic flow regimes. Spatially heterogeneous biofilms are especially known in spiral wound reverse osmosis (RO) and nanofiltration (NF) membrane filtration systems used for desalination and wastewater reuse to produce high quality (drinking) water. These spiral wound membrane modules contain mesh-like spacer structures used to create an intermembrane space and improve water mixing. Spacers create inhomogeneous water flow patterns resulting in zones favouring biofilm growth, possibly leading to biofouling thus hampering water production. Oxygen sensing planar optodes were used to visualize variations in oxygen decrease rates (ODR). ODR is an indication of biofilm activity. In this study, ODR images of multiple repetitive spacer areas in a membrane fouling simulator were averaged to produce high resolution, low noise ODR images. Averaging 40 individual spacer areas improved the ODR distribution image significantly and allowed comparison of biofilm patterning over a spacer structure at different positions in an RO filter. This method clearly showed that most active biofilm accumulated on and in direct vicinity of the spacer. The averaging method was also used to calculate the deviation of ODR patterning from individual spacer areas to the average ODR pattern, proposing a new approach to determine biofilm spatial heterogeneity. This study showed that the averaging method can be applied and that the improved, averaged ODR images can be used as an analytical, in-situ, non-destructive method to assess and quantify the effect of membrane installation operational parameters or different spacer geometries on biofilm development in spiral wound membrane systems characterized by complex hydrodynamic conditions.

  11. Testing for hydraulic characteristics of HIPER spacer grids

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyung Kyu; Lee, Kang Hee; Kang, Heung Seok; Lee, Young Ho; Kim, Jae Yong; Yoon, Kyung Ho

    2009-12-15

    The Korea Nuclear Fuel Co. requested the high frequency flow-induced vibration and pressure drop tests of top, mid, IFM, bottom grid candidates of HIPER and protective grid candidates of a commercial fuel. The following results were obtained for each test. 1) High frequency flow-induced vibration of HIPER spacer grids Measured maximum vibration amplitude of the HIPER mid grid was under 21 mm/s at lower region of the grid's center spring. The peak vibration amplitudes of the upper, IFM, and bottom grids were 5{approx}10 times less than that of the mid grid. Peak frequency associated with the peak amplitude have gradually increased with the flow velocity. This suggested that a high frequency vibration of grid was originated from the vortex shedding due to the thickness edge of grid strap. 2) Hydraulic vibration test of protective grids for a commercial fuel Peak vibration amplitudes of 16x16 type fuel protective grids were above 200 mm/s at the frontal direction of HyGrid 4. There might be a strong resonance near at the measurement point of the grid. Peak vibration amplitude of 17x17 type fuel were measured by 46.6 mm/s, 376.5 mm/s for the ACE7 and RFA protective grids in order. Peak frequency also had increasing trend with the bundle flow velocity. Measured pressure drops of 16x16 type fuel protective grids were comparatively higher than those of the reference fuel protective grids

  12. Identification and Radiofrequency Catheter Ablation of a Nonsustained Atrial Tachycardia at the Septal Mitral Annulus with the Use of a Noncontact Mapping System: A Case Report

    Directory of Open Access Journals (Sweden)

    Sumito Narita, MD

    2008-01-01

    Full Text Available Here we report a case of a 16-year old female with symptomatic nonsustained atrial tachycardia (NSAT originating from the septal mitral annulus. NSAT was induced by atrial burst pacing after an intravenous isoproterenol (ISP injection. The array mode of the noncontact mapping system (NCM allowed us to quickly identify the tachycardia focus at the septal mitral annulus, where the contact bipolar voltage map revealed no low voltage area (<0.5 mV. The NSAT was eliminated by a radiofrequency energy application to the identified tachycardia focus during sinus rhythm, and the patient has been free from any symptoms during 10 months of follow-up.

  13. Annulus fibrosus cells express and utilize C-C chemokine receptor 5 (CCR5) for migration.

    Science.gov (United States)

    Liu, Weijun; Liu, David; Zheng, Justin; Shi, Peng; Chou, Po-Hsin; Oh, Chundo; Chen, Di; An, Howard S; Chee, Ana

    2017-05-01

    Disc degeneration is associated with the progressive loss of the proteoglycan content of the intervertebral disc, decreased matrix synthesis, higher concentrations of proteolytic enzymes, and increased levels of proinflammatory cytokines. In previous studies, we have shown that C-C chemokine ligand (CCL)2, CCL3, and CCL5 are highly expressed by cultured nucleus pulposus (NP) and annulus fibrosus (AF) cells that have been treated by interleukin-1. The major function of these chemokines is to recruit immune cells into the disc. It is unclear if disc cells can respond to these chemokines. Recent studies by Phillips et al. (2015) showed that NP cells express a number of cytokines and chemokine receptors. The purpose of this study is to determine the gene and protein expression of C-C chemokine receptor (CCR)1, CCR2, and CCR5 in NP and AF cells, and to test if these receptors can respond to their ligands in these cells by cell signaling and migration. This is an in vitro study. For RNA, surface expression, and cell signaling studies, human cells were isolated from the NP and AF tissues collected after spine surgery or from donated spine segments (Gift of Hope Human Donor & Tissue Network of Illinois) and cultured in monolayer. The gene expression of human CCR1, CCR2, and CCR5 was analyzed using real-time polymerase chain reaction. The surface expression of CCR1, CCR2, and CCR5 was analyzed using flow cytometry and fluorescently tagged antibodies specific for these proteins. Extracellular signal-regulated kinase (ERK) phosphorylation was analyzed from the cell lysates of NP and AF cells treated with CCL2 and CCL5 for 1 hour using enzyme-linked immunosorbent assay. Migration of primary rabbit AF cells was assayed using 8-µm Corning Transwell inserts in the presence or absence of CCL5. This study was partially funded by a North American Spine Society 2014 Basic Research Grant Award ($50,000). RNA analysis showed that gene expression of CCR1, CCR2, and CCR5 was evident in

  14. 5 X 5 rod bundle flow field measurements downstream a PWR spacer grid

    Energy Technology Data Exchange (ETDEWEB)

    Castro, Higor F.P.; Silva, Vitor V A.; Santos, André A.C.; Veloso, Maria A.F., E-mail: higorfabiano@gmail.com, E-mail: mdora@nuclear.ufmg.br, E-mail: vitors@cdtn.br, E-mail: aacs@cdtn.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil); Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2017-07-01

    The spacer grids are structures present in nuclear fuel assembly of Pressurized Water Reactors (PWR). They play an important structural role and also assist in heat removal through the assembly by promoting increased turbulence of the flow. Understanding the flow dynamics downstream the spacer grid is paramount for fuel element design and analysis. This paper presents water flow velocity profiles measurements downstream a spacer grid in a 5 x 5 rod bundle test rig with the objective of highlighting important fluid dynamic behavior near the grid and supplying data for CFD simulation validation. These velocity profiles were obtained at two different heights downstream the spacer grid using a LDV (Laser Doppler Velocimetry) through the top of test rig. The turbulence intensities and patterns of the swirl and cross flow were evaluated. The tests were conducted for Reynolds numbers ranging from 1.8 x 10{sup 4} to 5.4 x 10{sup 4}. This experimental research was carried out in thermo-hydraulics laboratory of Nuclear Technology Development Center – CDTN. Results show great repeatability and low uncertainties (< 1.24 %). Details of the flow field show how the mixture and turbulence induced by the spacer grid quickly decays downstream the spacer grid. It is shown that the developed methodology can supply high resolution low uncertainty results that can be used for validation of CFD simulations. (author)

  15. 5 X 5 rod bundle flow field measurements downstream a PWR spacer grid

    International Nuclear Information System (INIS)

    Castro, Higor F.P.; Silva, Vitor V A.; Santos, André A.C.; Veloso, Maria A.F.

    2017-01-01

    The spacer grids are structures present in nuclear fuel assembly of Pressurized Water Reactors (PWR). They play an important structural role and also assist in heat removal through the assembly by promoting increased turbulence of the flow. Understanding the flow dynamics downstream the spacer grid is paramount for fuel element design and analysis. This paper presents water flow velocity profiles measurements downstream a spacer grid in a 5 x 5 rod bundle test rig with the objective of highlighting important fluid dynamic behavior near the grid and supplying data for CFD simulation validation. These velocity profiles were obtained at two different heights downstream the spacer grid using a LDV (Laser Doppler Velocimetry) through the top of test rig. The turbulence intensities and patterns of the swirl and cross flow were evaluated. The tests were conducted for Reynolds numbers ranging from 1.8 x 10 4 to 5.4 x 10 4 . This experimental research was carried out in thermo-hydraulics laboratory of Nuclear Technology Development Center – CDTN. Results show great repeatability and low uncertainties (< 1.24 %). Details of the flow field show how the mixture and turbulence induced by the spacer grid quickly decays downstream the spacer grid. It is shown that the developed methodology can supply high resolution low uncertainty results that can be used for validation of CFD simulations. (author)

  16. Mobility management in mobile IP

    Science.gov (United States)

    Medidi, Sirisha; Golshani, Forouzan

    2002-07-01

    There is an emerging interest in integrating mobile wireless communication with the Internet based on the Ipv6 technology. Many issues introduced by the mobility of users arise when such an integration is attempted. This paper addresses the problem of mobility management, i.e., that of tracking the current IP addresses of mobile terminals and sustaining active IP connections as mobiles move. The paper presents some architectural and mobility management options for integrating wireless access to the Internet. We then present performance results for Mobile IPv4, route optimization and Mobile IPv6.

  17. Determining factors of aerosol deposition for four pMDI-spacer combinations in an infant upper airway model.

    Science.gov (United States)

    Janssens, Hettie M; Krijgsman, Arno; Verbraak, Ton F M; Hop, Wim C J; de Jongste, Johan C; Tiddens, Harm A W M

    2004-01-01

    The aim of this study was to measure and compare the influence of tidal volume (Vt) respiratory rate (RR) and pMDI/spacer combination on aerosol deposition of 4 pMDI/spacer combinations, which are used for infants. An anatomically correct upper airway model of a 9-month-old infant was connected to a breathing simulator. Sinusoidal breathing patterns were simulated with; duty cycle T(i)/T(tot) = 0.42, Vt: 25, 50, 75, 100, 150, 200 ml (RR: 30 breaths/min); and RR: 20, 30, 42, 60, 78 breaths/min (Vt: 100 mL). pMDI/Spacers tested were: budesonide 200 microg/Nebuchamber, fluticasone 125 microg/Babyhaler and both budesonide and fluticasone with Aerochamber. Plastic spacers were detergent coated to reduce electrostatic charge. Spacer-output and lung dose were measured by a filter positioned between spacer and facemask or between model and breathing simulator. Particle size distribution of lung dose was assessed with an impactor during simulated breathing. Spacer-output was significantly positively correlated with Vt for all pMDI/spacers (all R > 0.77, p particles particles in the upper airways. Deposition of particles <2.1 microm is relatively flow independent. When electrostatic charge of spacers is reduced, lung dose is pMDI dependent and spacer independent.

  18. Predicting the impact of feed spacer modification on biofouling by hydraulic characterization and biofouling studies in membrane fouling simulators

    KAUST Repository

    Siddiqui, Amber

    2016-12-22

    Feed spacers are an essential part of spiral-wound reverse osmosis (RO) and nanofiltration (NF) membrane modules. Geometric modification of feed spacers is a potential option to reduce the impact of biofouling on the performance of membrane systems. The objective of this study was to evaluate the biofouling potential of two commercially available reference feed spacers and four modified feed spacers. The spacers were compared on hydraulic characterization and in biofouling studies with membrane fouling simulators (MFSs). The virgin feed spacer was characterized hydraulically by their resistance, measured in terms of feed channel pressure drop, performed by operating MFSs at varying feed water flow rates. Short-term (9 days) biofouling studies were carried out with nutrient dosage to the MFS feed water to accelerate the biofouling rate. Long-term (96 days) biofouling studies were done without nutrient dosage to the MFS feed water. Feed channel pressure drop was monitored and accumulation of active biomass was quantified by adenosine tri phosphate (ATP) determination. The six feed spacers were ranked on pressure drop (hydraulic characterization) and on biofouling impact (biofouling studies). Significantly different trends in hydraulic resistance and biofouling impact for the six feed spacers were observed. The same ranking for biofouling impact on the feed spacers was found for the (i) short-term biofouling study with nutrient dosage and the (ii) long-term biofouling study without nutrient dosage. The ranking for hydraulic resistance for six virgin feed spacers differed significantly from the ranking of the biofouling impact, indicating that hydraulic resistance of clean feed spacers does not predict the hydraulic resistance of biofouled feed spacers. Better geometric design of feed spacers can be a suitable approach to minimize impact of biofouling in spiral wound membrane systems.

  19. Mobile Election

    OpenAIRE

    Long, Elena; Lovitskii, Vladimir; Thrasher, Michael; Traynor, David

    2009-01-01

    Mobile phones have the potential of fostering political mobilisation. There is a significant political power in mobile technology. Like the Internet, mobile phones facilitate communication and rapid access to information. Compared to the Internet, however, mobile phone diffusion has reached a larger proportion of the population in most countries, and thus the impact of this new medium is conceivably greater. There are now more mobile phones in the UK than there are people (ave...

  20. Mobile Advertising

    OpenAIRE

    Alamuri, Lavanya

    2009-01-01

    The aim of this project was to get an understanding of how companies adopt mobile as an advertising medium. The literature review aided in framing a draft of the factors that affect mobile advertising adoption and possible forms of mobile advertising. Considering the scope of the thesis work, branding strategy, service costs, personalization and privacy and platform were considered to be the factors that could affect the mobile advertising adoption. A few possible forms on mobile device we...

  1. Restrictive enlargement of the pulmonary annulus at repair of tetralogy of Fallot: a comparative 10-year follow-up study.

    Science.gov (United States)

    Logoteta, Jana; Dullin, Lars; Hansen, Jan Hinnerk; Rickers, Carsten; Salehi Ravesh, Mona; Al Bulushi, Abdullah; Kristo, Ines; Wegner, Philip; Schumacher, Michael; Attmann, Tim; Scheewe, Jens; Kramer, Hans-Heiner

    2017-12-01

    Since 1996, our centre performs restrictive enlargement of the pulmonary annulus at surgical repair of tetralogy of Fallot. A transannular patch is only used if the z-score of the pulmonary annulus is smaller than -2. We sought to determine whether this strategy reduces pulmonary insufficiency (PI) and reoperation rate compared to a nationwide contemporary cohort that has not been operated using a uniform strategy. Eighty-seven tetralogy of Fallot patients were included in the study (Group 1). One hundred sixty-seven tetralogy of Fallot patients from the Competence Network for Congenital Heart Disease served as controls (Group 2). Clinical, echocardiographic, electrocardiogram, cardiovascular magnetic resonance and outcome data were analysed. Follow-up time since repair was not different between groups [12.9 (7.8-18.8) vs 13.1 (5.2-16.9) years, P = 0.96] while transannular patch rate was significantly lower in Group 1 (32.2% vs 64.7%, P < 0.001). Ten-year freedom from reoperation for PI was significantly higher in our cohort (98% vs 92%, P = 0.01). Multivariable analysis identified restrictive enlargement as the only predictor for no need of reoperation [hazard ratio 0.4 (95% confidence interval 0.24-0.84), P < 0.01]. In Group 1, cardiovascular magnetic resonance-derived volumes were smaller (indexed end-diastolic volume: 103 ± 24 vs 123 ± 31 ml/m2, P < 0.001; indexed end-systolic volume: 53 ± 19 vs 59 ± 20 ml/m2, P = 0.04) and regurgitation fraction was lower (21 ± 14 vs 31 ± 17%, P < 0.001). Restrictive enlargement of the pulmonary annulus reduces PI and limits the amount of right ventricular dilatation at intermediate-term follow-up. The need for reoperation to alleviate PI is significantly lower compared to a contemporary cohort. Restrictive enlargement strategy has a stronger influence on freedom from reoperation than the use of a transannular patch. WHO Main ID: DRKS00010087. URL: http

  2. A functional analysis of the spacer of V(DJ recombination signal sequences.

    Directory of Open Access Journals (Sweden)

    Alfred Ian Lee

    2003-10-01

    Full Text Available During lymphocyte development, V(DJ recombination assembles antigen receptor genes from component V, D, and J gene segments. These gene segments are flanked by a recombination signal sequence (RSS, which serves as the binding site for the recombination machinery. The murine Jbeta2.6 gene segment is a recombinationally inactive pseudogene, but examination of its RSS reveals no obvious reason for its failure to recombine. Mutagenesis of the Jbeta2.6 RSS demonstrates that the sequences of the heptamer, nonamer, and spacer are all important. Strikingly, changes solely in the spacer sequence can result in dramatic differences in the level of recombination. The subsequent analysis of a library of more than 4,000 spacer variants revealed that spacer residues of particular functional importance are correlated with their degree of conservation. Biochemical assays indicate distinct cooperation between the spacer and heptamer/nonamer along each step of the reaction pathway. The results suggest that the spacer serves not only to ensure the appropriate distance between the heptamer and nonamer but also regulates RSS activity by providing additional RAG:RSS interaction surfaces. We conclude that while RSSs are defined by a "digital" requirement for absolutely conserved nucleotides, the quality of RSS function is determined in an "analog" manner by numerous complex interactions between the RAG proteins and the less-well conserved nucleotides in the heptamer, the nonamer, and, importantly, the spacer. Those modulatory effects are accurately predicted by a new computational algorithm for "RSS information content." The interplay between such binary and multiplicative modes of interactions provides a general model for analyzing protein-DNA interactions in various biological systems.

  3. Experimental investigations of turbulent flows in rod bundles with and without spacer grids

    International Nuclear Information System (INIS)

    Trippe, G.

    1979-07-01

    In the thermofluiddynamic design of liquid metal cooled reactor fuel elements the lack of experimentally confirmed knowledge of the three-dimensional flow events in rod bundles provided with spacer grids has appeared as a significant problem. To close this gap of knowledge, detailed measurements of the local velocities were made on a 19-rod bundle model. The Pitot method of differential pressure measurements was used as the measuring system. In the first part of the work the fully developed flow regime not influenced by spacers was investigated. A simple relation was derived for distributing the mass flow among the subchannels of a rod bundle; it is but slightly dependent on the Reynolds number. This relation allows a quick, coarse calculation of the distribution of the undisturbed, fully developed mass flow in bundles with similar geometries. By evaluation of further experiments known from the literature, empirical relationships were found for the local velocity distribution within the subchannels of such bundles. In the second part the effect of grid shaped spacers was investigated. The three-dimensional flow events caused by the spacers were completely recorded and interpreted physically. The deeper understanding of these flow processes can now serve to improve the model concept used in the present design computer programs. Single results of the investigations which take primary importance are the quantitative relations existing between the changes of mass flow in the bundle boundary zone, caused by a spacer, and the geometry of this spacer. The transferability to other bundle geometries was discussed and delimited. Moreover, it was shown that the mass flow in the bundle boundary zone can be successively reduced by spacers placed one behind the other in the bundle. A noticeable dependence of flow events on the Reynolds number was not found for the range relevant in practical application (30.000 [de

  4. Hydrogel spacer distribution within the perirectal space in patients undergoing radiotherapy for prostate cancer: Impact of spacer symmetry on rectal dose reduction and the clinical consequences of hydrogel infiltration into the rectal wall.

    Science.gov (United States)

    Fischer-Valuck, Benjamin W; Chundury, Anupama; Gay, Hiram; Bosch, Walter; Michalski, Jeff

    Hydrogel prostate-rectum spacers, biomaterials placed between the prostate and rectum, continue to gain interest as a method to reduce or limit rectal dose during dose escalated prostate cancer radiation therapy. Because the spacer is initially injected into the perirectal space as a liquid, the final distribution can vary. The purpose of this study was to evaluate hydrogel spacer (SpaceOAR system) implantation and distribution from a recent prospective randomized control trial and correlate spacer symmetry with rectal dose reduction as well as rectal wall infiltration (RWI) to acute and late toxicity. T2-weighted magnetic resonance imaging sets of 149 patients enrolled in a prospective clinical trial who received transperineal spacer injection were assessed for hydrogel spacer midline symmetry and RWI using a semiqualitative scoring system. Symmetry was then correlated to rectal dose reduction using a Student t test (1-tailed, paired), whereas a Fisher exact test was used to correlate RWI with acute and late rectal toxicity. All patients had control treatment plans created before spacer injection. Hydrogel spacer was symmetrically placed at midline for 71 (47.7%) patients at the prostate midgland as well as 1 cm superior and inferior to midgland. The remaining 78 (50.9%) patients had some level of asymmetry, with only 2 (1.3%) having far lateral distribution (ie, >2 cm) of hydrogel spacer. As the hydrogel spacer became more asymmetric, the level of rectal dose reduction relative to their control plans decreased. However, all but the most asymmetrical 1.3% had significant rectal dose reduction (P < .05). Rectal wall hydrogel spacer infiltration was seen in 9 (6.0%) patients. There was no correlation between RWI and procedure-related adverse events or acute/late rectal toxicity. Significant reduction of rectal dose can still be achieved even in the setting of asymmetric hydrogel spacer placement. RWI does not correlate with patient complications. Copyright © 2016

  5. The Characteristics of natural convection heat transfer of Al2O3–water nano fluid flow in a vertical annulus pipe

    International Nuclear Information System (INIS)

    Reinaldy Nazar

    2016-01-01

    Results of several researches have shown that nano fluids have better thermal characteristics than conventional fluid (water). In this regard, ideas for using nano fluids as an alternative heat transfer fluid in the reactor coolant system have been well developed. Meanwhile the natural convection in a vertical annulus pipe is one of the important mechanisms of heat transfer and is found at the TRIGA research reactor, the new generation nuclear power plants and other energy conversion devices. On the other hand, the heat transfer characteristics of nano fluids in a vertical annulus pipe has not been known. Therefore, it is important to do research continuously to analyze the heat transfer nano fluids in a vertical annulus pipe. This study has carried out numerical analysis by using computer code of CFD (computational of fluids dynamic) on natural convection heat transfer characteristics of nano fluids flow of Al 2 O 3 -water 2 % volume in the vertical annulus pipe. The results showed an increase in heat transfer performance (Nusselt numbers - NU) by 20.5 % - 35 %. In natural convection mode with Rayleigh numbers 2.471 e +09 ≤ Ra ≤ 1.955 e +13 obtained empirical correlations for water is N U = 1.065 (R a (D H /x)) 0.179 and empirical correlations for Al 2 O 3 -water nano fluids is N U = 14.869 (R a (D H /x)) 0.115 .(author)

  6. Differentiation of adipose stem cells seeded towards annulus fibrosus cells on a designed poly(trimethylene carbonate) scaffold prepared by stereolithography

    NARCIS (Netherlands)

    Blanquer, Sebastien B. G.; Gebraad, Arjen W. H.; Miettinen, Susanna; Poot, Andre A.; Grijpma, Dirk W.; Haimi, Suvi P.

    2017-01-01

    Cell-based therapies could potentially restore the biomechanical function and enhance the self-repair capacity of annulus fibrosus (AF) tissue. However, choosing a suitable cell source and scaffold design are still key challenges. In this study, we assessed the in vitro ability of human adipose stem

  7. 3D echocardiographic analysis of aortic annulus for transcatheter aortic valve replacement using novel aortic valve quantification software: Comparison with computed tomography.

    Science.gov (United States)

    Mediratta, Anuj; Addetia, Karima; Medvedofsky, Diego; Schneider, Robert J; Kruse, Eric; Shah, Atman P; Nathan, Sandeep; Paul, Jonathan D; Blair, John E; Ota, Takeyoshi; Balkhy, Husam H; Patel, Amit R; Mor-Avi, Victor; Lang, Roberto M

    2017-05-01

    With the increasing use of transcatheter aortic valve replacement (TAVR) in patients with aortic stenosis (AS), computed tomography (CT) remains the standard for annulus sizing. However, 3D transesophageal echocardiography (TEE) has been an alternative in patients with contraindications to CT. We sought to (1) test the feasibility, accuracy, and reproducibility of prototype 3DTEE analysis software (Philips) for aortic annular measurements and (2) compare the new approach to the existing echocardiographic techniques. We prospectively studied 52 patients who underwent gated contrast CT, procedural 3DTEE, and TAVR. 3DTEE images were analyzed using novel semi-automated software designed for 3D measurements of the aortic root, which uses multiplanar reconstruction, similar to CT analysis. Aortic annulus measurements included area, perimeter, and diameter calculations from these measurements. The results were compared to CT-derived values. Additionally, 3D echocardiographic measurements (3D planimetry and mitral valve analysis software adapted for the aortic valve) were also compared to the CT reference values. 3DTEE image quality was sufficient in 90% of patients for aortic annulus measurements using the new software, which were in good agreement with CT (r-values: .89-.91) and small (software can accurately measure aortic annulus in patients with severe AS undergoing TAVR, in better agreement with CT than the existing methodology. Accordingly, intra-procedural TEE could potentially replace CT in patients where CT carries significant risk. © 2017, Wiley Periodicals, Inc.

  8. Correlating heat and mass transfer coefficients for thermosolutal convection within a porous annulus of a circular shape: case of internal pollutants spreading

    Science.gov (United States)

    Ragui, Karim; Boutra, Abdelkader; Bennacer, Rachid; Labsi, Nabila; Benkahla, Youb Khaled

    2018-02-01

    The main purpose of our investigation is to show the impact of pertinent parameters; such Lewis and porous thermal Rayleigh numbers as well as the buoyancy and the aspect ratios; on the double-diffusive convection phenomena which occur within a porous annulus; found between a cold (and less concentric) outer circular cylinder and a hot (and concentric) inner one, to come out with global correlations which predict the mean transfer rates in such annulus. To do so, the physical model for the momentum conservation equation is made using the Brinkman extension of the classical Darcy equation. The set of coupled equations is solved using the finite volume method and the SIMPLER algorithm. Summarizing the numerical predictions, global correlations of overall transfer within the porous annulus as a function of the governing studied parameters are set forth which predict within ±2% the numerical results. These correlations may count as a complement to previous researches done in the case a Newtonian-fluid annulus. It is to note that the validity of the computing code used was ascertained by comparing our results with the experimental data and numerical ones already available in the literature.

  9. Recognition and measurement gas-liquid two-phase flow in a vertical concentric annulus at high pressures

    Science.gov (United States)

    Li, Hao; Sun, Baojiang; Guo, Yanli; Gao, Yonghai; Zhao, Xinxin

    2018-02-01

    The air-water flow characteristics under pressure in the range of 1-6 MPa in a vertical annulus were evaluated in this report. Time-resolved bubble rising velocity and void fraction were also measured using an electrical void fraction meter. The results showed that the pressure has remarkable effect on the density, bubble size and rise velocity of the gas. Four flow patterns (bubble, cap-bubble, cap-slug, and churn) were also observed instead of Taylor bubble at high pressure. Additionally, the transition process from bubble to cap-bubble was investigated at atmospheric and high pressures, respectively. The results revealed that the flow regime transition criteria for atmospheric pressure do not work at high pressure, hence a new flow regime transition model for annular flow channel geometry was developed to predict the flow regime transition, which thereafter exhibited high accuracy at high pressure condition.

  10. Mobilities Design

    DEFF Research Database (Denmark)

    Jensen, Ole B.; Lanng, Ditte Bendix

    that of ‘mobilities design’. The book revolves around the following research question: How are design decisions and interventions staging mobilities? It builds upon the Staging Mobilities model (Jensen 2013) in an explorative inquiry into the problems and potentials of the design of mobilities. The exchange value...... between mobilities and design research is twofold. To mobilities research this means getting closer to the ‘material’, and to engage in the creative, explorative and experimental approaches of the design world which offer new potentials for innovative research. Design research, on the other hand, might...... enter into a fruitful relationship with mobilities research, offering a relational and mobile design thinking and a valuable base for a reflective design practice around the ubiquitous structures, spaces and systems of mobilities....

  11. Management of small aortic annulus in the era of sutureless valves: A comparative study among different biological options.

    Science.gov (United States)

    Ghoneim, Aly; Bouhout, Ismail; Demers, Philippe; Mazine, Amine; Francispillai, Mary; El-Hamamsy, Ismail; Carrier, Michel; Lamarche, Yoan; Bouchard, Denis

    2016-10-01

    Aortic valve replacement (AVR) in patients with a small aortic annulus is a challenging problem. The objective of this study was to compare 4 surgical approaches in terms of hemodynamics and perioperative outcomes. A retrospective single-center study included 351 consecutive patients with a small aortic annulus (≤21 mm) who underwent aortic valve surgery between January 2007 and December 2014. Surgical techniques included standard AVR in 259 (74%) patients, aortic root enlargement in 20 (6%), implantation of a stentless bioprosthesis in 23 (6%), and sutureless AVR in 49 (13%). Three hundred and eleven (89%) patients were female. The mean Logistic EuroSCORE II varied significantly among the groups and ranged from 6.5% ± 5.4% in the standard AVR group to 9.2% ± 4.7% in the stentless group. Early mortality occurred in 26 (7%) patients. Patients in the stentless group had the lowest aortic valve mean gradients on predischarge transthoracic echocardiography (10.9 ± 6.2 mm Hg; P < .001). In the stented group, the Trifecta prosthesis displayed the lowest postoperative mean transaortic gradient (10.3 ± 3.6; P < .001) with no severe prosthesis-patient mismatch. Postoperative gradients of the sutureless group were comparable with stented prostheses. In our study, stentless AVR and Trifecta bioprostheses had the best hemodynamic outcomes. The Perceval sutureless prosthesis provides reasonable hemodynamic performance and is a safe alternative. Copyright © 2016 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

  12. Three-dimensional development of tensile pre-strained annulus fibrosus cells for tissue regeneration: An in-vitro study

    Energy Technology Data Exchange (ETDEWEB)

    Chuah, Yon Jin [School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore 637459 (Singapore); Lee, Wu Chean [University Hospital Conventry & Warwickshire NHS Trust, Clifford Bridge Road, West Midlands CV2, 2DX (United Kingdom); Wong, Hee Kit [Department of Orthopedic Surgery, National University Health System, NUHS Tower Block Level 11, 1E Kent Ridge Road, Singapore 119228 (Singapore); Kang, Yuejun, E-mail: yuejun.kang@ntu.edu.sg [School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore 637459 (Singapore); Hee, Hwan Tak, E-mail: HTHee@ntu.edu.sg [School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore 637459 (Singapore); Pinnacle Spine & Scoliosis Centre, 3 Mount Elizabeth, Mount Elizabeth Medical Centre, #04-07, Singapore 228510 (Singapore); School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637459 (Singapore)

    2015-02-01

    Prior research has investigated the immediate response after application of tensile strain on annulus fibrosus (AF) cells for the past decade. Although mechanical strain can produce either catabolic or anabolic consequences to the cell monolayer, little is known on how to translate these findings into further tissue engineering applications. Till to date, the application and effect of tensile pre-strained cells to construct a three-dimensional (3D) AF tissue remains unknown. This study aims to investigate the effect of tensile pre-strained exposure of 1 to 24 h on the development of AF pellet culture for 3 weeks. Equibiaxial cyclic tensile strain was applied on AF monolayer cells over a period of 24 h, which was subsequently developed into a cell pellet. Investigation on cellular proliferation, phenotypic gene expression, and histological changes revealed that tensile pre-strain for 24 h had significant and lasting effect on the AF tissue development, with enhanced cell proliferation, and up-regulation of collagen type I, II, and aggrecan expression. Our results demonstrated the regenerative ability of AF cell pellets subjected to 24 h tensile pre-straining. Knowledge on the effects of tensile pre-strain exposure is necessary to optimize AF development for tissue reconstruction. Moreover, the tensile pre-strained cells may further be utilized in either cell therapy to treat mild disc degeneration disease, or the development of a disc construct for total disc replacement. - Highlights: • Establishment of tensile pre-strained cell line population for annulus development. • Tensile strain limits collagen gene expression declination in monolayer culture. • Tensile pre-strained cells up-regulate their matrix protein in 3D pellet culture.

  13. Knitting Technologies And Tensile Properties Of A Novel Curved Flat-Knitted Three-Dimensional Spacer Fabrics

    Directory of Open Access Journals (Sweden)

    Li Xiaoying

    2015-09-01

    Full Text Available This paper introduces a knitting technique for making innovative curved three-dimensional (3D spacer fabrics by the computer flat-knitting machine. During manufacturing, a number of reinforcement yarns made of aramid fibres are inserted into 3D spacer fabrics along the weft direction to enhance the fabric tensile properties. Curved, flat-knitted 3D spacer fabrics with different angles (in the warp direction were also developed. Tensile tests were carried out in the weft and warp directions for the two spacer fabrics (with and without reinforcement yarns, and their stress–strain curves were compared. The results showed that the reinforcement yarns can reduce the fabric deformation and improve tensile stress and dimensional stability of 3D spacer fabrics. This research can help the further study of 3D spacer fabric when applied to composites.

  14. Mobility Divides

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    Contemporary mobilities are cultural and social manifestations, and the mobile practices in the everyday life of billions of humans are re-configuring senses of place, self, other and relationships to the built environment. The way ‘mobile situations’ are staged in designed and built environments...... designs, but also how the situated and embodied mobile everyday life practices are staged ‘from below’ in concrete acts of choice concerning modes of mobilities, ways of moving and interacting. The ‘staging mobilites’ framework opens up to an understanding of the meaning of ‘mobilities design...

  15. A Study of Neutronics Effects of the Spacer Grids in a Typical PWR via Monte Carlo Calculation

    OpenAIRE

    Xuan Bach Tran; Nam Zin Cho

    2016-01-01

    Spacer grids play an important role in maintaining the proper form of the fuel assembly structure and ensuring the safety of reactor core design. This study applies the Monte Carlo method to the analysis of the neutronics effects of spacer grids in a typical pressurized water reactor (PWR). The core problem used to analyze the neutronics effects of spacer grids is a modified version of Korea Advanced Institute of Science and Technology benchmark problem 1B, based on an Advanced Power Reactor ...

  16. Primary limited lumbar discectomy with an annulus closure device: one-year clinical and radiographic results from a prospective, multi-center study.

    Science.gov (United States)

    Lequin, Michiel B; Barth, Martin; Thomė, Claudius; Bouma, Gerrit J

    2012-12-01

    Discectomy as a treatment for herniated lumbar discs results in outcomes after surgery that are not uniformly positive. Surgeons face the dilemma between limited nucleus removal which is associated with a higher risk of recurrence, or more aggressive nucleus removal which may lead to disc height loss and persistent back-pain. annulus closure devices may allow for the benefits of limited nucleus removal without the increased risk of recurrence. This is an interim report of an ongoing 24-month post-marketing study of the Barricaid® annulus closure device, consisting of a flexible polymer mesh that blocks the defect, held in place by a titanium bone anchor. We prospectively enrolled 45 patients at four hospitals, and implanted the Barricaid® after a limited discectomy. annulus defect size and volume of removed nucleus were recorded. Reherniations were reported, pain and function were monitored and imaging was performed at regular intervals during 24 months of follow-up. At 12 months postsurgery, pain and function were significantly improved, comparing favorably to reported results from limited discectomy. Disc height has been well maintained. One reherniation has occurred (2.4%), which was associated with a misplaced device. No device fracture, subsidence or migration has been observed. The use of an annulus closure device may provide a reduction in reherniation rate for lumbar discectomy patients with large annulus defects who are at the greatest risk of recurrence. Using such a device should provide the surgeon increased confidence in minimizing nucleus removal, which, in turn, may preserve disc height and biomechanics, reducing degeneration and associated poor clinical outcomes in the long-term. A randomized multicenter study evaluating limited discectomy with and without the Barricaid® is currently underway, and will provide a higher level of evidence.

  17. Effect of different commercial feed spacers on biofouling of reverse osmosis membrane systems: A numerical study

    KAUST Repository

    Bucs, Szilard

    2014-06-01

    Feed spacers and hydrodynamics have been found relevant for the impact of biofouling on performance in reverse osmosis (RO) and nanofiltration (NF) membrane systems.The objectives of this study on biofouling development were to determine the impact of (i) linear flow velocity and bacterial cell load, (ii) biomass location and (iii) various feed spacer geometries as applied in practice as well as a modified geometry spacer.A three-dimensional mathematical model for biofouling of feed spacer channels including hydrodynamics, solute mass transport and biofilm formation was developed in COMSOL Multiphysics and MATLAB software.Results of this study indicate that the feed channel pressure drop increase caused by biofilm formation can be reduced by using thicker and/or modified feed spacer geometry and/or a lower flow rate in the feed channel. The increase of feed channel pressure drop by biomass accumulation is shown to be strongly influenced by the location of biomass. Results of numerical simulations are in satisfactory agreement with experimental data, indicating that this micro-scale mechanistic model is representative for practice. The developed model can help to understand better the biofouling process of spiral-wound RO and NF membrane systems and to develop strategies to reduce and control biofouling. © 2013 Elsevier B.V.

  18. Detection and characterization of spacer integration intermediates in type I-E CRISPR-Cas system.

    Science.gov (United States)

    Arslan, Zihni; Hermanns, Veronica; Wurm, Reinhild; Wagner, Rolf; Pul, Ümit

    2014-07-01

    The adaptation against foreign nucleic acids by the CRISPR-Cas system (Clustered Regularly Interspaced Short Palindromic Repeats and CRISPR-associated proteins) depends on the insertion of foreign nucleic acid-derived sequences into the CRISPR array as novel spacers by still unknown mechanism. We identified and characterized in Escherichia coli intermediate states of spacer integration and mapped the integration site at the chromosomal CRISPR array in vivo. The results show that the insertion of new spacers occurs by site-specific nicking at both strands of the leader proximal repeat in a staggered way and is accompanied by joining of the resulting 5'-ends of the repeat strands with the 3'-ends of the incoming spacer. This concerted cleavage-ligation reaction depends on the metal-binding center of Cas1 protein and requires the presence of Cas2. By acquisition assays using plasmid-located CRISPR array with mutated repeat sequences, we demonstrate that the primary sequence of the first repeat is crucial for cleavage of the CRISPR array and the ligation of new spacer DNA. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

  19. Shape optimization of spacer grids / development of a FE model their buckling analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, B. M.; Im, S. Y.; Chang, J. H.; Jang, I. G.; Choi, K. H. [Korea Advanced Institute of Science and Technology, Taejon (Korea)

    2000-04-01

    An optimal design method is adopted for spacer grids. For contact analysis, a typical cell out of repeated pattern in the assembly is modeled. A commercial code, ABAQUS, is used for detailed analysis of frictional contact. For the optimization, design variables are taken from geometric parameters and several objectives are considered. The optimized shapes and resulting performances are discussed and shown satisfactory. This method is illustrated as a good design tool for structures that has complex behavior due to friction and wear. In this study considered is the buckling of spacer grids in the nuclear fuel assembly, which are required to have a sufficient strength against an accident like earthquake. Special attention is given to the modeling of the spot-welding and the constraints between the unit spacers assembled together : it is found that a proper treatment of the constraints is critical for accurate assessment of the buckling behavior including strain localization at the point of spot welding. The buckling strength of the 17 x 17 spacer grid, which is difficult to analyze due to a large number of degrees of freedom, is obtained from analysis for the smaller models 3 x 3, 5 x 5, 7 x 7 and 9 x 9 spacer grids. 9 refs., 36 figs., 8 tabs. (Author)

  20. Fourteen internal transcribed spacers in the circular ribosomal DNA of Euglena gracilis.

    Science.gov (United States)

    Schnare, M N; Cook, J R; Gray, M W

    1990-09-05

    Cytoplasmic ribosomes from Euglena gracilis contain 16 rRNA components. These include the typical 5 S, 5.8 S and 19 S rRNAs that are found in other eukaryotes as well as 13 discrete small RNAs that interact to form the equivalent of eukaryotic 25-28 S rRNA (accompanying paper). We have utilized DNA sequencing techniques to establish that genes for all of these RNAs, with the exception of 5 S rRNA, are encoded by the 11,500 base-pair circular rDNA of E. gracilis. We have determined the relative positions of the coding regions for the 19 S rRNA and the 14 components (including 5.8 S rRNA) of the large subunit rRNA, thereby establishing that the genes for each of these rRNAs are separated by internal transcribed spacers. We conclude that sequences corresponding to these spacers are removed post-transcriptionally from a high molecular weight pre-rRNA, resulting in a multiply fragmented large subunit rRNA. Internal transcribed spacers, in positions analogous to some of these additional Euglena rDNA spacers, have been found in the rDNA of other organisms and organelles. This finding supports the view that at least some internal transcribed spacers may have been present at an early stage in the evolution of rRNA genes.

  1. Air-water flooding in multirod channels: effects of spacer grids and blockages

    International Nuclear Information System (INIS)

    Cha, Jong Hee; Jun, Hyung Gil

    1993-01-01

    This paper presents the experimental results on flooding of countercurrent flow in vertical multirod channels, which consists of falling water film and upward air flow. In particular, the effects of spacer grids, with and without mixing vane, and of blockage in the multirod bundle on the behaviour of flooding were investigated. The 5 x 5 zircaloy tube bundle was used for the test section. The comparison of previous analytical models and empirical correlations with present data on flooding showed that the existing models and correlations predict much higher flooding curves. The spacer grid causes the lower flooding air flow rate to compare with the bare rod bundle. However, the mixing spacer grids need a higher flooding air flow rate for a constant liquid flow rate than the spacer grids without mixing vanes. The bundle containing blockages has the highest flooding air flow rate among the bundles with spacer grids and blokages. Empirical flooding correlations for the three types of test section have been made. (Author)

  2. Simulation study of transfer characteristics for spacer-filled membrane distillation desalination modules

    International Nuclear Information System (INIS)

    Chang, Hsuan; Hsu, Jian-An; Chang, Cheng-Liang; Ho, Chii-Dong; Cheng, Tung-Wen

    2017-01-01

    Highlights: • A 3D CFD model takes in transmembrane heat and mass transfer developed. • DCMD modules using spacer-filled and empty channels for desalination simulated. • Fluid flow, heat transfer and mass transfer profiles revealed. • Correlations of friction factor and Nusselt number developed. - Abstract: Membrane distillation (MD) is an emerging and promising membrane separation process, which can directly utilize renewable thermal energy or low-grade waste heat, for applications in water or wastewater treatment and food industry. However, a major drawback of MD process is its low energy efficiency. Spacer is the most suggested and studied eddy promoter to enhance the heat and mass transfer, which further improves both the separation and the energy utilization performance, of MD processes. This paper presents the results of a 3D computational fluid dynamics (CFD) simulation of DCMD (direct contact membrane distillation) modules using channels with and without spacers for desalination application. The model employs permeable wall boundary condition to take into account the transmembrane heat and mass transfer and simulates the entire module length. The simulation reveals similar fluctuating distributions of temperature polarization coefficient, transmembrane heat and mass fluxes as well as the shear stress on the membrane surface along the entire module length. Correlations have been developed for friction factor and average Nusselt number. These correlations are useful for the analysis and design of DCMD modules. The extent of heat transfer enhancement by spacers depends on the geometry of spacers and the Reynolds number of fluid.

  3. Using cathode spacers to minimize reactor size in air cathode microbial fuel cells

    KAUST Repository

    Yang, Qiao

    2012-04-01

    Scaling up microbial fuel cells (MFCs) will require more compact reactor designs. Spacers can be used to minimize the reactor size without adversely affecting performance. A single 1.5mm expanded plastic spacer (S1.5) produced a maximum power density (973±26mWm -2) that was similar to that of an MFC with the cathode exposed directly to air (no spacer). However, a very thin spacer (1.3mm) reduced power by 33%. Completely covering the air cathode with a solid plate did not eliminate power generation, indicating oxygen leakage into the reactor. The S1.5 spacer slightly increased columbic efficiencies (from 20% to 24%) as a result of reduced oxygen transfer into the system. Based on operating conditions (1000ς, CE=20%), it was estimated that 0.9Lh -1 of air would be needed for 1m 2 of cathode area suggesting active air flow may be needed for larger scale MFCs. © 2012 Elsevier Ltd.

  4. Mobile Workforce, Mobile Technology, Mobile Threats

    International Nuclear Information System (INIS)

    Garcia, J.

    2015-01-01

    Mobile technologies' introduction into the world of safeguards business processes such as inspection creates tremendous opportunity for novel approaches and could result in a number of improvements to such processes. Mobile applications are certainly the wave of the future. The success of the application ecosystems has shown that users want full fidelity, highly-usable, simple purpose applications with simple installation, quick responses and, of course, access to network resources at all times. But the counterpart to opportunity is risk, and the widespread adoption of mobile technologies requires a deep understanding of the threats and vulnerabilities inherent in mobile technologies. Modern mobile devices can be characterized as small computers. As such, the threats against computing infrastructure apply to mobile devices. Meanwhile, the attributes of mobile technology that make it such an obvious benefit over traditional computing platforms all have elements of risk: pervasive, always-on networking; diverse ecosystems; lack of centralized control; constantly shifting technological foundations; intense competition among competitors in the marketplace; the scale of the installation base (from millions to billions); and many more. This paper will explore the diverse and massive environment of mobile, the number of attackers and vast opportunities for compromise. The paper will explain how mobile devices prove valuable targets to both advanced and persistent attackers as well as less-skilled casual hackers. Organized crime, national intelligence agencies, corporate espionage are all part of the landscape. (author)

  5. Microbiologic Evaluation of Cotton and Polytetrafluoroethylene (PTFE) Tape as Endodontic Spacer Materials in Primary Molars An in Vivo Study.

    Science.gov (United States)

    Prabhakar, Attiguppe Ramasetty; Dixit, Kratika; Raju, O S

    PTFE tape, which is commonly used as plumber's tape is an inorganic, non-fibrous, ribbon like material. The aim of this study was to evaluate PTFE tape as endodontic spacer material and to compare it with commonly used spacer material that is cotton, in primary teeth. Seventeen children undergoing pulpectomy of lower second primary molar bilaterally were included in the study. Cotton and PTFE tape were placed as spacers on each side randomly. Samples were taken from the access cavity at baseline and after seven days to check for microbial leakage. Spacer materials were also checked for microbial contamination. The results revealed that there was a significant increase in the bacterial colony count after seven days in cotton group. The access cavities were also positive for microbial leakage in the cotton group where the spacers showed positive growth. In PTFE group only two samples showed microbial contamination of spacer and out of two only one sample showed contamination of access cavity along with spacer. Within the limitations of this study, it can be concluded that PTFE tape performed better than cotton as endodontic spacer material. Thus, PTFE tape can be recommended as an endodontic spacer material as an alternative to cotton in primary teeth.

  6. Mobile economy

    OpenAIRE

    Pousttchi, Key

    2004-01-01

    Mobile economy : Transaktionen, Prozesse, Anwendungen und Dienste ; 4. Workshop Mobile Commerce, 02.-03. Februar 2004, Univ. Augsburg / K. Turowski ... (Hrsg.). - Bonn : Ges. für Informatik, 2004. - 189 S. : Ill., graph. Darst. - (GI-Edition : Proceedings ; 42)

  7. Mobile marketing

    OpenAIRE

    KLEČKOVÁ, Zuzana

    2013-01-01

    The main aim of this thesis was to provide a comprehensive overview of the mobile marketing and analyze selected campaigns of Czech mobile marketing in comparison to world successful campaigns. The research contained studying of available literature about the theme to gain general knowledge about the issue. The theoretical part of the thesis contains predominantly various definitions of mobile marketing and its tools, advantages of these tools and some information about Mobile Marketing Assoc...

  8. Mobile marketing

    OpenAIRE

    Gause, Matěj

    2012-01-01

    The goal of bachelor's thesis on the theme "Mobile marketing" is to outline its development and why is this new phenomen so important for all modern companies around the world. The work is not about simple description of mobile marketing media but it vividly informs about the latest trends and news from the world of mobile apps and games. It presents the most successful mobile apps which registered more than billion downloads and from their unique characteristics it unveils great potential of...

  9. Effect of Weld Properties on the Crush Strength of the PWR Spacer Grid

    Directory of Open Access Journals (Sweden)

    Kee-nam Song

    2012-01-01

    Full Text Available Mechanical properties in a weld zone are different from those in the base material because of different microstructures. A spacer grid in PWR fuel is a structural component with an interconnected and welded array of slotted grid straps. Previous research on the strength analyses of the spacer grid was performed using base material properties owing to a lack of mechanical properties in the weld zone. In this study, based on the mechanical properties in the weld zone of the spacer grid recently obtained by an instrumented indentation technique, the strength analyses considering the mechanical properties in the weld zone were performed, and the analysis results were compared with the previous research.

  10. Assessment of cover to reinforcement in slabs using different spacer and tying distances

    Directory of Open Access Journals (Sweden)

    A. P. Maran

    Full Text Available ABSTRACTGiven that the durability of structures is directly related to the thickness of the cover to reinforcement, it is essential to ensure minimum cover is achieved when building a structure. However, studies show that this is not always the case. One of the reasons for the this problem is the lack of indication, in structural projects, of the positioning of spacers. This situation is compounded by the lack of standards and regulations on the use of spacers (i.e. minimum quantities and required layout. This study assesses three different spacer distances and two different tying distances in order to examine the influence of these factors in the cover to reinforcement. To achieve so, three slabs were prepared in situ using different arrangements. After demoulding, cover thickness was determined using a digital covermeter. It was observed that the factors investigated have a significant influence in the final cover.

  11. A high-performance channel engineered charge-plasma-based MOSFET with high-κ spacer

    Science.gov (United States)

    Shan, Chan; Wang, Ying; Luo, Xin; Bao, Meng-tian; Yu, Cheng-hao; Cao, Fei

    2017-12-01

    In this paper, the performance of graded channel double-gate MOSFET (GC-DGFET) that utilizes the charge-plasma concept and a high-κ spacer is investigated through 2-D device simulations. The results demonstrate that GC-DGFET with high-κ spacer can effectively improve the ON-state driving current (ION) and reduce the OFF-leakage current (IOFF). We find that reduction of the initial energy barrier between the source and channel is the origin of this ION enhancement. The reason for the IOFF reduction is identified to be the extension of the effective channel length owing to the fringing field via high-κ spacers. Consequently, these devices offer enhanced performance by reducing the total gate-to-gate capacitance (Cgg) and decreasing the intrinsic delay (τ).

  12. Measurement of droplet dynamics across grid spacer in mist cooling of subchannel of PWR

    International Nuclear Information System (INIS)

    Lee, S.L.; Sheen, H.J.; Cho, S.K.; Issapour, I.

    1984-01-01

    An experiment was conducted of the dynamics and heat transfer of a droplet-vapor mist flow across a test grid spacer in a flow channel of 2 x 2 electrically heated simulation fuel rods. Embedded thermocouples were used to measure the rod cladding temperature and an unshielded Chromel-Alumel thermocouple was transversed in the center of the subchannel to measure the temperature of the water and steam coolant phases at various axial locations. Thermocouples were also embedded in the test grid spacer. Optical measurements of the size and velocity distributions of droplets and the velocity distribution of the superheated steam were made by special laser-Doppler anemometry techniques through quartz glass windows immediately upstream and downstream of the test grid spacer. Experiments over a range of steam and injected water flow rates and rod heat flux have been performed and some representative results and discussions are presented

  13. [Cervical adaptation of complete cast crowns of various metal alloys, with and without die spacers].

    Science.gov (United States)

    Stephano, C B; Roselino, R F; Roselino, R B; Campos, G M

    1989-01-01

    A metallic replica from a dental preparation for crown was used to make 8 class-IV stone dies. The wax patterns for the casting of the crowns were obtained in two conditions: a) from the stone die with no spacer; and b) from the stone die with an acrylic spacer. Thus, 64 metallic crowns were casted, using 4 different alloys: DURACAST (Cu-Al), NICROCAST (Ni-Cr) and DURABOND (Ni-Cr), and gold. The casted crowns were fitted in the metallic replica and measured as to the cervical discrepance of fitting. The results showed that the use of die spacers decreases the clinical discrepancies of fitting of the casted crowns (in a statistically significant level), no matter the metallic alloy employed.

  14. Designing Mobilities

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    Within the so-called ‘mobilities turn’ (Adey 2010; Cresswell 2006; Urry 2007) much research has taken place during the last decade bringing mobilities into the centre of sociological analysis. However, the materiality and spatiality of artefacts, infrastructures, and sites hosting mobilities are ......: motorway ecologies, bicycle systems design, urban shopping malls and a train transit hub....

  15. Mobilities Design

    DEFF Research Database (Denmark)

    Lanng, Ditte Bendix; Wind, Simon; Jensen, Ole B.

    2017-01-01

    utilitarian transport from A to B; they constitute a rich societal phenomenon with, for example, social, cultural, sensorial, emotional, and material dimensions. The article proposes two fruitful links between the mobilities turn and the designerly examination of mobilities spaces. First, the mobilities turn...

  16. Subversive Mobilities

    DEFF Research Database (Denmark)

    Thelle, Mikkel

    2013-01-01

    The article approaches mobility through a cultural history of urban conflict. Using a case of “The Copenhagen Trouble,“ a series of riots in the Danish capital around 1900, a space of subversive mobilities is delineated. These turn-of-the-century riots points to a new pattern of mobile gathering...

  17. Intensive mobilities

    DEFF Research Database (Denmark)

    Vannini, Phillip; Bissell, David; Jensen, Ole B.

    which relate to transport, housing and employment. Yet we argue that the experiential dimensions of long distance mobilities have not received the attention that they deserve within geographical research on mobilities. This paper combines ideas from mobilities research and contemporary social theory...

  18. Temperature dependence of magnetoresistive properties in bottom spin valve films employing very thin Cu spacers

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Soonchul [School of Electronic Engineering, Soongsil University, Seoul 156-743 (Korea, Republic of)]. E-mail: jschul@ssu.ac.kr; Seigler, Michael A. [Seagate Research, Pittsburgh, PA 15222 (United States)

    2007-09-15

    Temperature dependence of magnetoresistive properties in bottom spin valve films having very thin Cu spacers are reported. NiFeCr55 A/NiFe10 A/IrMn70 A/CoFetA/Ru4 A/CoFe(t+3)A/Cu/CoFe tA/NiFe10 A/Ta50 A bottom spin valve films were deposited using a DC magnetron sputter deposition system. Magnetoresistance (MR) ratio reached a maximum of 13.5% and 11.9% at the Cu thickness of 10.4 A, when the thickness of the CoFe layers t was 20 and 10 A, respectively. Unlike the top spin valves reported earlier, the dip in the MR ratio was not observed when the interlayer coupling between the free layer and reference layer became zero. Sheet resistance change (DR{sub s}) reached a maximum of 4.22 {omega}/{open_square} at the Cu spacer thickness of 10 A when the CoFe thickness t was 10 A. Temperature dependences of MR ratio, DR{sub s}, interlayer coupling field (H {sub i}), and sensitivity showed mostly monotonic decrease as the temperature was increased up to 200 deg. C. It turns out that DR{sub s} for the film having 10.4 A of Cu spacer thickness at 200 deg. C was larger than the DR{sub s} for the film having 20 A of Cu spacer thickness at 40 deg. C. This suggests a high output voltage of the spin valve sensor made of the thin Cu spacer even at high operating temperature. These very thin Cu spacers could be utilized for very small devices where the interlayer coupling field is dominated by high demagnetizing fields.

  19. Mobile Probes in Mobile Learning

    DEFF Research Database (Denmark)

    Ørngreen, Rikke; Blomhøj, Ulla; Duvaa, Uffe

    In this paper experiences from using mobile probes in educational design of a mobile learning application is presented. The probing process stems from the cultural probe method, and was influenced by qualitative interview and inquiry approaches. In the project, the mobile phone was not only acting...... as an agent for acquiring empirical data (as the situation in hitherto mobile probe settings) but was also the technological medium for which data should say something about (mobile learning). Consequently, not only the content of the data but also the ways in which data was delivered and handled, provided...... a valuable dimension for investigating mobile use. The data was collected at the same time as design activities took place and the collective data was analysed based on user experience goals and cognitive processes from interaction design and mobile learning. The mobile probe increased the knowledge base...

  20. Renal failure after placement of an articulating, antibiotic impregnated polymethylmethacrlyate hip spacer

    Directory of Open Access Journals (Sweden)

    Robert P. Runner, MD

    2018-03-01

    Full Text Available A 58-year-old male presented with native joint septic arthritis of the hip and osteomyelitis. After treatment with an articulating antibiotic spacer, he developed acute renal failure requiring dialysis. He continued to have elevated serum tobramycin levels exclusively from the antibiotic spacer elution as no intravenous tobramycin was used. Subsequent explantation was required to correct his renal failure. Although renal failure after antibiotic impregnated cement placement is rare, the risk of this potential complication should be considered preoperatively and in the postoperative management of these patients.

  1. Spacer stitching’, an innovative material feeding technology for improved thermal resistance

    Science.gov (United States)

    Saeed, H.; Rödel, H.; Krzywinski, S.; Hes, L.

    2017-10-01

    This paper investigates the problems associated with heat loss occurring at the points of needle insertion. The insulation material at stitching points is compressed by sewing thread tensions and consequently the air entrapped is forced to leave its structure. It results in poor thermal insulation at the points of needle insertions. An innovative material feeding technology, ‘Spacer stitching’ is developed which addresses the state of the art of cold spots with a simpler and much efficient method. A comparison of sewing samples of conventional sewing technology with the spacer stitching is carried out in this research paper to study the improvement in thermal properties.

  2. Automatic actuation of a dry powder inhaler into a nonelectrostatic spacer

    DEFF Research Database (Denmark)

    Bisgaard, H

    1998-01-01

    This article describes a new "automatic spacer" device, which has been developed to improve the delivery of inhaled medication to young children. In the device, a dry powder inhaler (DPI) is mechanically actuated into a nonelectrostatic spacer, producing an aerosol cloud of fine drug particles (a...... of the actuation (relative standard deviation, 12%), and a prolonged residence time of the fine particle aerosol (half-life of the fallout of the fine particles, 82 s). These features should prove advantageous in the treatment of young children with inhaled medication....

  3. Microbial fuel cells with an integrated spacer and separate anode and cathode modules

    KAUST Repository

    He, Weihua

    2016-01-01

    A new type of scalable MFC was developed based on using alternating graphite fiber brush array anode modules and dual cathode modules in order to simplify construction, operation, and maintenance of the electrodes. The modular MFC design was tested with a single (two-sided) cathode module with a specific surface area of 29 m2 m−3 based on a total liquid volume (1.4 L; 20 m2 m−3 using the total reactor volume of 2 L), and two brush anode modules. Three different types of spacers were used in the cathode module to provide structural stability, and enhance air flow relative to previous cassette (combined anode–cathode) designs: a low-profile wire spacer; a rigid polycarbonate column spacer; and a flexible plastic mesh spacer. The best performance was obtained using the wire spacer that produced a maximum power density of 1100 ± 10 mW m−2 of cathode (32 ± 0.3 W m−3 based on liquid volume) with an acetate-amended wastewater (COD = 1010 ± 30 mg L−1), compared to 1010 ± 10 mW m−2 for the column and 650 ± 20 mW m−2 for the mesh spacers. Anode potentials were unaffected by the different types of spacers. Raw domestic wastewater produced a maximum of 400 ± 8 mW m−2 under fed batch conditions (wire-spacers), which is one of the highest power densities for this fuel. Over time the maximum power was reduced to 300 ± 10 mW m−2 and 275 ± 7 mW m−2 for the two anode compartments, with only slightly less power of 250 ± 20 mW m−2 obtained under continuous flow conditions. In fixed-resistance tests, the average COD removal was 57 ± 5% at a hydraulic retention time of 8 h. These results show that this modular MFC design can both simplify reactor construction and enable relatively high power generation from even relatively dilute wastewater.

  4. Heterogeneous Diversity of Spacers within CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats)

    Science.gov (United States)

    He, Jiankui; Deem, Michael W.

    2010-09-01

    Clustered regularly interspaced short palindromic repeats (CRISPR) in bacterial and archaeal DNA have recently been shown to be a new type of antiviral immune system in these organisms. We here study the diversity of spacers in CRISPR under selective pressure. We propose a population dynamics model that explains the biological observation that the leader-proximal end of CRISPR is more diversified and the leader-distal end of CRISPR is more conserved. This result is shown to be in agreement with recent experiments. Our results show that the CRISPR spacer structure is influenced by and provides a record of the viral challenges that bacteria face.

  5. Self-structuring of lamellar bridged silsesquioxanes with long side spacers.

    Science.gov (United States)

    Fernandes, Mariana; Nobre, Sónia S; Xu, Qinghong; Carcel, Carole; Cachia, Jean Nicolas; Cattoën, Xavier; Sousa, José M; Ferreira, Rute A S; Carlos, Luís D; Santilli, Celso V; Wong Chi Man, Michel; Bermudez, Verónica de Zea

    2011-09-22

    Diurea cross-linked bridged silsesquioxanes (BSs) C(10)C(n)C(10) derived from organosilane precursors, including decylene chains as side spacers and alkylene chains with variable length as central spacers (EtO)(3)Si-(CH(2))(10)-Y-(CH(2))(n)-Y-(CH(2))(10)-Si(OEt)(3) (n = 7, 9-12; Y = urea group and Et = ethyl), have been synthesized through the combination of self-directed assembly and an acid-catalyzed sol-gel route involving the addition of dimethylsulfoxide (DMSO) and a large excess of water. This new family of hybrids has enabled us to conclude that the length of the side spacers plays a unique role in the structuring of alkylene-based BSs, although their morphology remains unaffected. All the samples adopt a lamellar structure. While the alkylene chains are totally disordered in the case of the C(10)C(7)C(10) sample, a variable proportion of all-trans and gauche conformers exists in the materials with longer central spacers. The highest degree of structuring occurs for n = 9. The inclusion of decylene instead of propylene chains as side spacers leads to the formation of a stronger hydrogen-bonded urea-urea array as evidenced by two dimensional correlation Fourier transform infrared spectroscopic analysis. The emission spectra and emission quantum yields of the C(10)C(n)C(10) materials are similar to those reported for diurea cross-linked alkylene-based BSs incorporating propylene chains as side spacers and prepared under different experimental conditions. The emission of the C(10)C(n)C(10) hybrids is ascribed to the overlap of two distinct components that occur within the urea cross-linkages and within the siliceous nanodomains. Time-resolved photoluminescence spectroscopy has provided evidence that the average distance between the siliceous domains and the urea cross-links is similar in the C(10)C(n)C(10) BSs and in oxyethylene-based hybrid analogues incorporating propylene chains as side spacers (diureasils), an indication that the longer side chains in the

  6. Optimization of base-to-emitter spacer thickness to maximize the frequency response of bipolar transistors

    Science.gov (United States)

    Lee, Wai-Kit; Chan, Alain C. K.; Chan, Mansun

    2005-04-01

    The impacts of base-to-emitter spacer thickness on the unity gain frequency ( fT), base resistance ( rB), base collector capacitance ( CBC) and maximum oscillation frequency ( fmax) of a bipolar junction transistor (BJT) are studied. Using the extracted Y-parameters from a simulated device with structural parameters calibrated to an actual process, the resulting fT and fmax with different spacer thickness is reported. A tradeoff between peak fT and fmax is observed and the process window to obtain high fT and fmax is proposed.

  7. Comparison of velocity and temperature fields for two types of spacers in an annular channel

    Directory of Open Access Journals (Sweden)

    Lávička David

    2012-04-01

    Full Text Available The paper deals with measurement of flow field using a modern laser method (PIV in an annular channel of very small dimension - a fuel cell model. The velocity field was measured in several positions and plains around the spacer. The measurement was extended also to record temperatures by thermocouples soldered into stainless-steel tube wall. The measurement was focused on cooling process of the preheated fuel cell tube model, where the tube was very slowly flooded with water. Main result of the paper is comparison of two spacer's designs with respect to measured velocity and temperature fields.

  8. Mobile Semiotics

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    2013-01-01

    This chapter aims to understand the mobile condition of contemporary life with a particular view to the signifying dimension of the environment and its ‘readability’. The chapter explores the potentials of semiotics and its relationship to the new mobilities literature. What takes place...... is a ‘mobile sense making’ where signs and materially situated meanings connect to the moving human body and thus create particular challenges and complexities of making sense of the world. The chapter includes notions of mobility systems and socio-technical networks in order to show how a ‘semiotic layer’ may...... work to afford or restrict mobile practices....

  9. Hole-transfer induced energy transfer in perylene diimide dyads with a donor-spacer-acceptor motif.

    Science.gov (United States)

    Kölle, Patrick; Pugliesi, Igor; Langhals, Heinz; Wilcken, Roland; Esterbauer, Andreas J; de Vivie-Riedle, Regina; Riedle, Eberhard

    2015-10-14

    We investigate the photoinduced dynamics of perylene diimide dyads based on a donor-spacer-acceptor motif with polyyne spacers of varying length by pump-probe spectroscopy, time resolved fluorescence, chemical variation and quantum chemistry. While the dyads with pyridine based polyyne spacers undergo energy transfer with near-unity quantum efficiency, in the dyads with phenyl based polyyne spacers the energy transfer efficiency drops below 50%. This suggests the presence of a competing electron transfer process from the spacer to the energy donor as the excitation sink. Transient absorption spectra, however, reveal that the spacer actually mediates the energy transfer dynamics. The ground state bleach features of the polyyne spacers appear due to the electron transfer decay with the same time constant present in the rise of the ground state bleach and stimulated emission of the perylene energy acceptor. Although the electron transfer process initially quenches the fluorescence of the donor it does not inhibit energy transfer to the perylene energy acceptor. The transient signatures reveal that electron and energy transfer processes are sequential and indicate that the donor-spacer electron transfer state itself is responsible for the energy transfer. Through the introduction of a Dexter blocker unit into the spacer we can clearly exclude any through bond Dexter-type energy transfer. Ab initio calculations on the donor-spacer and the donor-spacer-acceptor systems reveal the existence of a bright charge transfer state that is close in energy to the locally excited state of the acceptor. Multipole-multipole interactions between the bright charge transfer state and the acceptor state enable the energy transfer. We term this mechanism coupled hole-transfer FRET. These dyads represent a first example that shows how electron transfer can be connected to energy transfer for use in novel photovoltaic and optoelectronic devices.

  10. Mobile Lexicography

    DEFF Research Database (Denmark)

    Køhler Simonsen, Henrik

    2014-01-01

    Users are already mobile, but the question is to which extent knowledge-based dictionary apps are designed for the mobile user situation. The objective of this article is to analyse the characteristics of the mobile user situation and to look further into the stationary user situation...... and the mobile user situation. The analysis is based on an empirical survey involving ten medical doctors and a monolingual app designed to support cognitive lexicographic functions, cf. (Tarp 2006:61-64). In test A the doctors looked up five medical terms while sitting down at a desk and in test B the doctors......:565), and it was found that the information access success of the mobile user situation is lower than that of the stationary user situation, primarily because users navigate in the physical world and in the mobile device at the same time. The data also suggest that the mobile user situation is not fully compatible...

  11. Scattering and mobility in indium gallium arsenide channel, pseudomorphic high electron mobility transistors (InGaAs pHEMTs)

    International Nuclear Information System (INIS)

    Pearson, J.L.

    1999-03-01

    Extensive transport measurements have been completed on deep and shallow-channelled InGaAs p-HEMTs of varying growth temperature, indium content, spacer thickness and doping density, with a view to a thorough characterisation, both in the metallic and the localised regimes. Particular emphasis was given to MBE grown layers, with characteristics applicable for device use, but low measurement temperatures were necessary to resolve the elastic scattering mechanisms. Measurements made in the metallic regime included transport and quantum mobility - the former over a range of temperatures between 1.5K to 300K. Conductivity measurements were also acquired in the strong localisation regime between about 1.5K and 100K. Experimentally determined parameters were tested for comparison with those predicted by an electrostatic model. Excellent agreement was obtained for carrier density. Other parameters were less well predicted, but the relevant experimental measurements, including linear depletion of the 2DEG, were sensitive to any excess doping above a 'critical' value determined by the model. At low temperature (1.5K), it was found that in all samples tested, transport mobility was strongly limited at all carrier densities by a large q mechanism, possibly intrinsic to the channel. This was ascribed either to scattering by the long-range potentials arising from the indium concentration fluctuations or fluctuations in the thickness of the channel layer. This mechanism dominates the transport at low carrier densities for all samples, but at high carrier density, an additional mechanism is significant for samples with the thinnest spacers tested (2.5nm). This is ascribed to direct electron interaction with the states of the donor layer, and produces a characteristic transport mobility peak. At higher carrier densities, past the peak, quantum mobility was found only to increase monotonically in value. Remote ionised impurity scattering while significant, particularly for samples

  12. Novel anthracycline-spacer-beta-glucuronide, -beta-glucoside, and -beta-galactoside prodrugs for application in selective chemotherapy

    NARCIS (Netherlands)

    Leenders, RGG; Damen, EWP; Bijsterveld, EJA; Scheeren, HW; Houba, PHJ; van der Meulen-Muileman, IH; Boven, E; Haisma, HJ

    A series of anthracycline prodrugs containing an immolative spacer was synthesized for application in selective chemotherapy. The prodrugs having the general structure anthracycline-spacer-beta-glycoside were designed to be activated by beta-glucuronidase or beta-galactosidase. Prodrugs with

  13. Interference-driven spacer acquisition is dominant over naive and primed adaptation in a native CRISPR-Cas system

    NARCIS (Netherlands)

    Staals, Raymond H.J.; Jackson, Simon A.; Biswas, Ambarish; Brouns, Stan J.J.; Brown, Chris M.; Fineran, Peter C.

    2016-01-01

    CRISPR-Cas systems provide bacteria with adaptive immunity against foreign nucleic acids by acquiring short, invader-derived sequences called spacers. Here, we use high-throughput sequencing to analyse millions of spacer acquisition events in wild-type populations of Pectobacterium atrosepticum.

  14. A Study of Neutronics Effects of the Spacer Grids in a Typical PWR via Monte Carlo Calculation

    Directory of Open Access Journals (Sweden)

    Xuan Bach Tran

    2016-02-01

    Full Text Available Spacer grids play an important role in maintaining the proper form of the fuel assembly structure and ensuring the safety of reactor core design. This study applies the Monte Carlo method to the analysis of the neutronics effects of spacer grids in a typical pressurized water reactor (PWR. The core problem used to analyze the neutronics effects of spacer grids is a modified version of Korea Advanced Institute of Science and Technology benchmark problem 1B, based on an Advanced Power Reactor 1400 (APR1400 core model. The spacer grids are modeled and added to this test problem in various ways. Then, by running MCNP5 for all cases of spacer grid modeling, some important numerical results, such as the effective multiplication factor, the spatial distributions of neutron flux, and its energy spectrum are obtained. The numerical results of each case of spacer grid modeling are analyzed and compared to assess which type has more advantages in accuracy of numerical results and effectiveness in terms of geometry building. The conclusion is that the most realistic modeling for Monte Carlo calculation is the “volume-preserving” streamlined heterogeneous spacer grids, but the “banded” dissolution spacer grids modeling is a more practical yet accurate model for routine (deterministic analysis.

  15. Unusual low-energy near-infrared bands for ferrocenyl-naphthalimide donor-acceptor dyads with aromatic spacer groups

    DEFF Research Database (Denmark)

    Tagg, Tei; Kjærgaard, Henrik Grum; Lane, Joseph R.

    2015-01-01

    Time-dependent density functional theory (TDDFT) calculations for a series of donor-spacer-acceptor (D-S-A) molecules with phenyl (1), biphenyl (2), and anthryl (3) spacers interpolated between the ferrocenylalkene donor and -C≡C-4-naphthalimido acceptor components predicted the presence of weak,...

  16. Plasmin-activated doxorubicin prodrugs containing a spacer reduce tumor growth and angiogenesis without systemic toxicity

    NARCIS (Netherlands)

    Devy, L.; Groot, F.M.H. de; Blacher, S.; Hajitou, A.; Beusker, P.H.; Scheeren, J.W.; Foidart, J.M.; Noel, A.

    2004-01-01

    To generate doxorubicin (Dox) specifically at the tumor site, the chemotherapeutic agent was incorporated into a prodrug by linkage to a peptide specifically recognized by plasmin, which is overproduced in many cancers. ST-9905, which contains an elongated self-elimination spacer, is activated more

  17. Phylogenetic relationships of the genus Phanerochaete inferred from the internal transcribed spacer region

    Science.gov (United States)

    Theodorus H. de Koker; Karen K. Nakasone; Jacques Haarhof; Harold H. Burdsall; Bernard J.H. Janse

    2003-01-01

    Phanerochaete is a genus of resupinate homobasidiomycetes that are saprophytic on woody debris and logs. Morphological studies in the past indicated that Phanerochaete is a heterogeneous assemblage of species. In this study the internal transcribed spacer (ITS) region of the nuclear ribosomal DNA was used to test the monophyly of the genus Phanerochaete and to infer...

  18. Exploring backbone-cation alkyl spacers for multi-cation side chain anion exchange membranes

    Science.gov (United States)

    Zhu, Liang; Yu, Xuedi; Hickner, Michael A.

    2018-01-01

    In order to systematically study how the arrangement of cations on the side chain and length of alkyl spacers between cations impact the performance of multi-cation AEMs for alkaline fuel cells, a series of polyphenylene oxide (PPO)-based AEMs with different cationic side chains were synthesized. This work resulted in samples with two or three cations in a side chain pendant to the PPO backbone. More importantly, the length of the spacer between cations varied from 3 methylene (-CH2-) (C3) groups to 8 methylene (C8) groups. The highest conductivity, up to 99 mS/cm in liquid water at room temperature, was observed for the triple-cation side chain AEM with pentyl (C5) or hexyl (C6) spacers. The multi-cation AEMs were found to have decreased water uptake and ionic conductivity when the spacer chains between cations were lengthened from pentyl (C5) or hexyl (C6) to octyl (C8) linking groups. The triple-cation membranes with pentyl (C5) or hexyl (C6) groups between cations showed greatest stability after immersion in 1 M NaOH at 80 °C for 500 h.

  19. Response of an annular electrostatic probe for a right cylindrical spacer

    DEFF Research Database (Denmark)

    Johansson, Torben; MacAllister, I. W.

    2002-01-01

    The response of an annular electrostatic probe mounted in an electrode is examined with reference to a right cylindrical spacer. The study involves using the probe λ function to derive characteristic parameters. These parameters enable the response of the probe to different charge distributions...

  20. rDNA internal transcribed spacer sequence analysis of Lycoris Hert ...

    African Journals Online (AJOL)

    This paper suggested that the likelihood of hybrid origin of Lycoris species was supported and ITS could be used as a good molecular marker to identify plants of Lycoris. Keywords: Lycoris Hert., internal transcribed spacer (ITS), molecular taxonomy, interspecific relationship. African Journal of Biotechnology Vol. 11(29), pp.

  1. The sequence of spacers between the consensus sequences modulates the strength of procaryotic promoters

    DEFF Research Database (Denmark)

    Jensen, Peter Ruhdal; Hammer, Karin

    1998-01-01

    A library of synthetic promoters for Lactococcus lactis was constructed, in which the known consensus sequences were kept constant while the sequences of the separating spacers were randomized. The library consists of 38 promoters which differ in strength from 0.3 relative units, and up to more t......-reactors and cell factories....

  2. Plane wave scattering from a plasmonic nanowire array spacer-separated from a plasmonic film

    Science.gov (United States)

    Thomas, Arun; Trivedi, Rahul; Dhawan, Anuj

    2016-06-01

    In this paper, we present a theoretical analysis of the electromagnetic response of a plasmonic nanowire-spacer-plasmonic film system. The analytical solution presented in this paper is a full-wave solution, which is used to compute the fields scattered by the plasmonic nanostructure system on illumination by a plane electromagnetic wave. The physical structure comprises of an array of plasmonic nanowires made of a plasmonic metal such as gold or silver placed over a plasmonic film of the same material and separated from it by a dielectric spacer such as silica or alumina. Such a nanostructure exhibits a spectrum that is extremely sensitive to various geometric and electromagnetic parameters such as spacer thickness and spacer refractive index, which makes it favourable for various sensing applications such as chemical and biological sensing, strain sensing, position sensing, vibration sensing, and thickness sensing. We report a comparison of our analytical solution with a numerical rigorous coupled wave analysis of the same structure with the plasmonic medium being treated as local in nature.

  3. Peri-Prosthetic Knee Infection Management: Spacers Loaded with Two or Three Antibiotic Agents.

    Science.gov (United States)

    Ortola, David Joaquin; Fenga, Domenico; Marcellino, Sandra; Rosi, Massimiliano; Centofanti, Francesco; Rosa, Michele Attilio

    2017-07-01

    The purpose of this work was to compare pre-made antibiotic-loaded spacers with two commercially available antibiotic agents and custom-made cements with three antibiotic agents added. We evaluated: (a) the validity of our procedures, (b) the control of the rate of infection in the long term, (c) complications, and (d) quality of life and patient satisfaction. A retrospective cohort study was performed on 112 consecutively treated patients between January 2010 and December 2013; 56 patients were treated with a pre-formed cement spacer (clindamycin + gentamicin), and 56 patients were treated with a spacer loaded with three antibiotic agents (clindamycin + gentamicin + vancomycin). Demographic data were collected: Classification of infection according to criteria of Cierny-Mader; microbiologic results; number of previous operations; and years of disease. Infection control or relapse after at least 18 months of follow-up was evaluated. Complications were recorded. Every patient completed the SF-36 test and Oxford Knee Score. With a follow-up of 32.87 months (standard deviation 12.04), at the end of treatment, amputation occurred in three of 112 patients because of recurrence of infection, and one patient died from other causes not related to the infection. The study population presented a rate of recurrence of infection of 2.70%. Our results suggest that a two stage re-implant with three antibiotic agents added to the spacer should be considered to avoid rescue procedures, especially in patients with multi-resistant micro-organism infections.

  4. Mechanical Properties Of 3D-Structure Composites Based On Warp-Knitted Spacer Fabrics

    Directory of Open Access Journals (Sweden)

    Chen Si

    2015-06-01

    Full Text Available In this paper, the mechanical properties (compression and impact behaviours of three-dimension structure (3D-structure composites based on warp-knitted spacer fabrics have been thoroughly investigated. In order to discuss the effect of fabric structural parameters on the mechanical performance of composites, six different types of warp-knitted spacer fabrics having different structural parameters (such as outer layer structure, diameter of spacer yarn, spacer yarn inclination angle and thickness were involved for comparison study. The 3D-structure composites were fabricated based on a flexible polyurethane foam. The produced composites were characterised for compression and impact properties. The findings obtained indicate that the fabric structural parameters have strong influence on the compression and impact responses of 3D-structure composites. Additionally, the impact test carried out on the 3D-structure composites shows that the impact loads do not affect the integrity of composite structure. All the results reveal that the product exhibits promising mechanical performance and its service life can be sustained.

  5. Anomalous DNA binding by E2 regulatory protein driven by spacer sequence TATA.

    Science.gov (United States)

    Xi, Zhiqun; Zhang, Yongli; Hegde, Rashmi S; Shakked, Zippora; Crothers, Donald M

    2010-06-01

    We have investigated the anomalously weak binding of human papillomavirus (HPV) regulatory protein E2 to a DNA target containing the spacer sequence TATA. Experiments in magnesium (Mg(2+)) and calcium (Ca(2+)) ion buffers revealed a marked reduction in cutting by DNase I at the CpG sequence in the protein-binding site 3' to the TATA spacer sequence, Studies of the cation dependence of DNA-E2 affinities showed that upon E2 binding the TATA sequence releases approximately twice as many Mg(2+) ions as the average of the other spacer sequences. Binding experiments for TATA spacer relative to ATAT showed that in potassium ion (K(+)) the E2 affinity of the two sequences is nearly equal, but the relative dissociation constant (K(d)) for TATA increases in the order K(+ )TATA relative to ATAT is independent of ion concentration, whereas for Mg(2+) the affinity for TATA drops sharply as ion concentration increases. Thus, ions of increasing positive charge density increasingly distort the E2 binding site, weakening the affinity for protein. In the case of Mg(2+), additional ions are bound to TATA that require displacement for protein binding. We suggest that the TATA sequence may bias the DNA structure towards a conformation that binds the protein relatively weakly.

  6. The Interspinous Spacer: A New Posterior Dynamic Stabilization Concept for Prevention of Adjacent Segment Disease

    Directory of Open Access Journals (Sweden)

    Antoine Nachanakian

    2013-01-01

    Full Text Available Introduction. Posterior Dynamic stabilization using the interspinous spacer device is a known to be used as an alternative to rigid fusion in neurogenic claudication patients in the absence of macro instability. Actually, it plays an important in the management of adjacent segment disease in previously fused lumbar spine. Materials and Method. We report our experience with posterior dynamic stabilization using an interspinous spacer. 134 cases performed in our institution between September 2008 and August 2012 with different lumbar spine pathologies. The ages of our patients were between 40 and 72 years, with a mean age of 57 years. After almost 4 years of follow up in our patient and comparing their outcome to our previous serious we found that in some case the interspinous distracter has an important role not only in the treatment of adjacent segment disease but also in its prevention. Results and Discussion. Clinical improvement was noted in ISD-treated patients, with high satisfaction rate. At first, radicular pain improves with more than 3/10 reduction of the mean score on visual analog scale (VAS. In addition, disability score as well as disc height and lordotic angle showed major improvement at 3 to 6 months post operatively. And, no adjacent segment disease was reported in the patient operated with interspinous spacer. Conclusion. The interspinous spacer is safe and efficient modality to be used not only as a treatment of adjacent segment disease but also as a preventive measure in patients necessitating rigid fusion.

  7. Silver Nanoparticles Stabilised by Cationic Gemini Surfactants with Variable Spacer Length

    Directory of Open Access Journals (Sweden)

    Martin Pisárčik

    2017-10-01

    Full Text Available The present study is focused on the synthesis and investigation of the physicochemical and biological properties of silver nanoparticles stabilized with a series of cationic gemini surfactants having a polymethylene spacer of variable length. UV-VIS spectroscopy, dynamic light scattering, scanning electron microscopy and zeta potential measurements were applied to provide physicochemical characterization of the silver nanoparticles. The mean size values of the nanoparticles were found to be in the 50 to 115 nm range. From the nanoparticle size distributions and scanning electron microscopy images it results that a population of small nanoparticles with the size of several nanometers was confirmed if the nanoparticles were stabilized with gemini molecules with either a short methylene spacer (two or four −CH2− groups or a long spacer (12 −CH2− groups. The average zeta potential value for silver nanoparticles stabilized with gemini molecules is roughly independent of gemini surfactant spacer length and is approx. +58 mV. An interaction model between silver nanoparticles and gemini molecules which reflects the gained experimental data, is suggested. Microbicidal activity determinations revealed that the silver nanoparticles stabilized with gemini surfactants are more efficient against Gram-negative bacteria and yeasts, which has a direct relation to the interaction mechanism of nanoparticles with the bacterial cell membrane and its structural composition.

  8. Mobility Work

    DEFF Research Database (Denmark)

    Bardram, Jakob Eyvind; Bossen, Claus

    2005-01-01

    of coordination necessary in cooperative work, but focuses, we argue, mainly on the temporal aspects of cooperative work. As a supplement, the concept of mobility work focuses on the spatial aspects of cooperative work. Whereas actors seek to diminish the amount of articulation work needed in collaboration......We posit the concept of Mobility Work to describe efforts of moving about people and things as part of accomplishing tasks. Mobility work can be seen as a spatial parallel to the concept of articulation work proposed by the sociologist Anselm Strauss. Articulation work describes efforts...... by constructing Standard Operation Procedures (SOPs), actors minimise mobility work by constructing Standard Operation Configurations (SOCs). We apply the concept of mobility work to the ethnography of hospital work, and argue that mobility arises because of the need to get access to people, places, knowledge and...

  9. Mobilities Design

    DEFF Research Database (Denmark)

    Jensen, Ole B.; Lanng, Ditte Bendix; Wind, Simon

    2016-01-01

    In this paper, we identify the nexus between design (architecture, urban design, service design, etc.) and mobilities as a new and emerging research field. In this paper, we apply a “situational mobilities” perspective and take point of departure in the pragmatist question: “What design decisions...... and interventions affords this particular mobile situation?” The paper presents the contours of an emerging research agenda within mobilities research. The advent of “mobilities design” as an emerging research field points towards a critical interest in the material as well as practical consequences of contemporary......-making. The paper proposes that increased understanding of the material affordances facilitated through design provides important insight to planning and policymaking that at times might be in risk of becoming too detached from the everyday life of the mobile subject within contemporary mobilities landscapes....

  10. Investigation of conditions inside the reactor building annulus of a PWR plant of KONVOI type in case of severe accidents with increased containment leakages

    International Nuclear Information System (INIS)

    Bakalov, Ivan; Sonnenkalb, Martin

    2018-01-01

    Improvements of the implemented severe accident management (SAM) concepts have been done in all operating German NPPs after the Fukushima Daiichi accidents following recommendations of the German Reactor Safety Commission (RSK) and as a result of the stress test being performed. The efficiency of newly developed severe accident management guidelines (SAMG) for a PWR KONVOI reference plant related to the mitigation of challenging conditions inside the reactor building (RB) annulus due to increased containment leakages during severe accidents have been assessed. Based on two representative severe accident scenarios the releases of both hydrogen and radionuclides into the RB annulus have been predicted with different boundary conditions. The accident scenarios have been analysed without and with the impact of several SAM measures (already planned or proposed in addition), which turned out to be efficient to mitigate the consequences. The work was done within the frame of a research project financially supported by the Federal Ministry BMUB.

  11. Modeling the effect of spacers and biofouling on forward osmosis performance

    KAUST Repository

    Mosqueira Santillán, María José

    2014-11-01

    Currently, the most utilized desalination technology is reverse osmosis (RO), where a membrane is used as a physical barrier to separate the salts from the seawater, using high hydraulic pressure as driving force. A major problem in RO systems is biofouling, caused by severe growth of bacterial biofilms. Both, the need of an external energy input, as well as biofouling, impose a high cost on RO operation. Forward osmosis (FO) is an alternative membrane process that uses an osmotic pressure difference as driving force. FO uses a concentrated draw solution to generate high osmotic pressure, which extracts water across a semi permeable membrane from a feed solution. One of the main advantages of FO is the limited amount of external energy required to extract water from the feed solution. The objective of this research is the assessment of the impact of spacers, separating the membrane sheets, and biofouling on the FO system performance. This type of studies allow the optimization of membrane devices and operational conditions. For this, a two dimensional numerical model for FO systems was developed using computational fluid dynamics (CFD). This model allowed the evaluation of the impact of (i) spacers and (ii) biofilm, and (iii) the combined impact of spacers and biofilm on the performance of FO systems. The results obtained showed that the presence of spacers improved the performance of FO systems. Cavity configuration spacer gave the higher water flux across the membrane in clean systems; whereas for biofouled systems, the submerged configuration showed a better performance. In absence of spacers, the thickness or amount of biofilm is inversely proportional with the water flux. Furthermore, membrane surface coverage of the biofilm is more important than the amount of biofilm in terms of the impact on the performance. The numerical model can be adapted with other parameters (e.g. membrane and spacer thickness, feed and draw solution, solution concentration, etc.) to

  12. How type II CRISPR-Cas establish immunity through Cas1-Cas2-mediated spacer integration.

    Science.gov (United States)

    Xiao, Yibei; Ng, Sherwin; Nam, Ki Hyun; Ke, Ailong

    2017-10-05

    CRISPR (clustered regularly interspaced short palindromic repeats) and the nearby Cas (CRISPR-associated) operon establish an RNA-based adaptive immunity system in prokaryotes. Molecular memory is created when a short foreign DNA-derived prespacer is integrated into the CRISPR array as a new spacer. Whereas the RNA-guided CRISPR interference mechanism varies widely among CRISPR-Cas systems, the spacer integration mechanism is essentially identical. The conserved Cas1 and Cas2 proteins form an integrase complex consisting of two distal Cas1 dimers bridged by a Cas2 dimer. The prespacer is bound by Cas1-Cas2 as a dual-forked DNA, and the terminal 3'-OH of each 3' overhang serves as an attacking nucleophile during integration. The prespacer is preferentially integrated into the leader-proximal region of the CRISPR array, guided by the leader sequence and a pair of inverted repeats inside the CRISPR repeat. Spacer integration in the well-studied Escherichia coli type I-E CRISPR system also relies on the bacterial integration host factor. In type II-A CRISPR, however, Cas1-Cas2 alone integrates spacers efficiently in vitro; other Cas proteins (such as Cas9 and Csn2) have accessory roles in the biogenesis phase of prespacers. Here we present four structural snapshots from the type II-A system of Enterococcus faecalis Cas1 and Cas2 during spacer integration. Enterococcus faecalis Cas1-Cas2 selectively binds to a splayed 30-base-pair prespacer bearing 4-nucleotide 3' overhangs. Three molecular events take place upon encountering a target: first, the Cas1-Cas2-prespacer complex searches for half-sites stochastically, then it preferentially interacts with the leader-side CRISPR repeat, and finally, it catalyses a nucleophilic attack that connects one strand of the leader-proximal repeat to the prespacer 3' overhang. Recognition of the spacer half-site requires DNA bending and leads to full integration. We derive a mechanistic framework to explain the stepwise spacer

  13. Barriers and supports to implementation of MDI/spacer use in nine Canadian pediatric emergency departments: a qualitative study

    Directory of Open Access Journals (Sweden)

    Graham Ian D

    2009-10-01

    Full Text Available Abstract Background Despite recent research supporting the use of metered dose inhalers with spacer devices (MDI/spacers in pediatric emergency departments (PEDs for acute exacerbations of asthma, uptake of this practice has been slow. The objectives of this study were to determine the barriers and supports to implementing MDI/spacer research and to identify factors associated with early and late adoption of MDI/spacers in Canadian PEDs. Methods Using a comparative case study design, we classified nine tertiary care pediatric hospital PEDs based on their stage of implementation. Data were collected using focus group interviews with physicians, registered nurses (RNs, and respiratory therapists (RTs, and individual interviews with both patient care and medical directors at each site. Initial coding was based on the Ottawa Model of Research Use (OMRU categories of elements known to influence the uptake of innovations. Results One hundred and fifty healthcare professionals from nine different healthcare institutions participated in this study. Lack of leadership in the form of a research champion, a lack of consensus about the benefits of MDI/spacers among staff, perceived resistance from patients/parents, and perceived increased cost and workload associated with MDI/spacer use were the most prevalent barriers to the adoption of the MDI/spacer. Common strategies used by early-adopting sites included the active participation of all professional groups in the adoption process in addition to a well-planned and executed educational component for staff, patients, and families. Early adopter sites were also more likely to have the MDI/spacer included in a clinical protocol/pathway. Conclusion Potential barriers and supports to implementation have been identified that will help EDs adopt MDI/spacer use. Future interventions intended to increase MDI/spacer use in PEDs will need to be sensitive to the barriers identified in this study.

  14. Shape-memory-alloy-based smart knee spacer for total knee arthroplasty: 3D CAD modelling and a computational study.

    Science.gov (United States)

    Gautam, Arvind; Callejas, Miguel A; Acharyya, Amit; Acharyya, Swati Ghosh

    2018-03-22

    This study introduced a shape memory alloy (SMA)-based smart knee spacer for total knee arthroplasty (TKA). Subsequently, a 3D CAD model of a smart tibial component of TKA was designed in Solidworks software, and verified using a finite element analysis in ANSYS Workbench. The two major properties of the SMA (NiTi), the pseudoelasticity (PE) and shape memory effect (SME), were exploited, modelled, and analysed for a TKA application. The effectiveness of the proposed model was verified in ANSYS Workbench through the finite element analysis (FEA) of the maximum deformation and equivalent (von Mises) stress distribution. The proposed model was also compared with a polymethylmethacrylate (PMMA)-based spacer for the upper portion of the tibial component for three subjects with body mass index (BMI) of 23.88, 31.09, and 38.39. The proposed SMA -based smart knee spacer contained 96.66978% less deformation with a standard deviation of 0.01738 than that of the corresponding PMMA based counterpart for the same load and flexion angle. Based on the maximum deformation analysis, the PMMA-based spacer had 30 times more permanent deformation than that of the proposed SMA-based spacer for the same load and flexion angle. The SME property of the lower portion of the tibial component for fixation of the spacer at its position was verified by an FEA in ANSYS. Wherein, a strain life-based fatigue analysis was performed and tested for the PE and SME built spacers through the FEA. Therefore, the SMA-based smart knee spacer eliminated the drawbacks of the PMMA-based spacer, including spacer fracture, loosening, dislocation, tilting or translation, and knee subluxation. Copyright © 2018. Published by Elsevier Ltd.

  15. Inspection and Gamma-Ray Dose Rate Measurements of the Annulus of the VSC-17 Concrete Spent Nuclear Fuel Storage Cask

    Energy Technology Data Exchange (ETDEWEB)

    P. L. Winston

    2007-09-01

    The air cooling annulus of the Ventilated Storage Cask (VSC)-17 spent fuel storage cask was inspected using a Toshiba 7 mm (1/4”) CCD video camera. The dose rates observed in the annular space were measured to provide a reference for the activity to which the camera(s) being tested were being exposed. No gross degradation, pitting, or general corrosion was observed.

  16. Descriptions and diagrams of the primary and annulus ventilation systems of the double-shell tank farms as of January 1988

    International Nuclear Information System (INIS)

    Blackman, A.E.; Waters, E.D.

    1994-01-01

    This document is a compilation of information describing the ventilation systems of the Double-Shell Tank farms (214-AN, -AP, -AW, -AW, -AY, -AZ, and -SY). A general description of the primary tank and annulus ventilation systems is given along with specific information on the high efficiency particulate air (HEPA) filters, condensers, preheaters, exhaust fans, and piping. This information is considered to be current as of January 1988. 38 refs, 20 figs, 30 tabs

  17. CT-angiography-based evaluation of the aortic annulus for prosthesis sizing in transcatheter aortic valve implantation (TAVI-predictive value and optimal thresholds for major anatomic parameters.

    Directory of Open Access Journals (Sweden)

    Florian Schwarz

    Full Text Available BACKGROUND/OBJECTIVES: To evaluate the predictive value of CT-derived measurements of the aortic annulus for prosthesis sizing in transcatheter aortic valve implantation (TAVI and to calculate optimal cutoff values for the selection of various prosthesis sizes. METHODS: The local IRB waived approval for this single-center retrospective analysis. Of 441 consecutive TAVI-patients, 90 were excluded (death within 30 days: 13; more than mild aortic regurgitation: 10; other reasons: 67. In the remaining 351 patients, the CoreValve (Medtronic and the Edwards Sapien XT valve (Edwards Lifesciences were implanted in 235 and 116 patients. Optimal prosthesis size was determined during TAVI by inflation of a balloon catheter at the aortic annulus. All patients had undergone CT-angiography of the heart or body trunk prior to TAVI. Using these datasets, the diameter of the long and short axis as well as the circumference and the area of the aortic annulus were measured. Multi-Class Receiver-Operator-Curve analyses were used to determine the predictive value of all variables and to define optimal cutoff-values. RESULTS: Differences between patients who underwent implantation of the small, medium or large prosthesis were significant for all except the large vs. medium CoreValve (all p's<0.05. Furthermore, mean diameter, annulus area and circumference had equally high predictive value for prosthesis size for both manufacturers (multi-class AUC's: 0.80, 0.88, 0.91, 0.88, 0.88, 0.89. Using the calculated optimal cutoff-values, prosthesis size is predicted correctly in 85% of cases. CONCLUSION: CT-based aortic root measurements permit excellent prediction of the prosthesis size considered optimal during TAVI.

  18. Mobil marketing

    OpenAIRE

    Engelová, Kateřina

    2006-01-01

    Mobil marketing - reklama a podpora prodeje prostřednictvím mobilních telefonů. Technologické a kulturní předpoklady vzniku tohoto odvětví. Mobil marketing a marketingový mix, možnosti synergie. Nástroje mobil marketingu - reklamní SMS a MMS, lokační služby, soutěže, ankety a hlasování, věrnostní systémy, mobilní obsah. Subjekty mobil marketingu. M-komerce. Využití pro podnikové aplikace.

  19. MHD mixed convection in a vertical annulus filled with Al2O3–water nanofluid considering nanoparticle migration

    International Nuclear Information System (INIS)

    Malvandi, A.; Safaei, M.R.; Kaffash, M.H.; Ganji, D.D.

    2015-01-01

    In the current study, an MHD mixed convection of alumina/water nanofluid inside a vertical annular pipe is investigated theoretically. The model used for the nanofluid mixture involves Brownian motion and thermophoretic diffusivities in order to take into account the effects of nanoparticle migration. Since the thermophoresis is the main mechanism of the nanoparticle migration, different temperature gradients have been imposed using the asymmetric heating. Considering hydrodynamically and thermally fully developed flow, the governing equations have been reduced to two-point ordinary boundary value differential equations and they have been solved numerically. It is revealed that the imposed thermal asymmetry would change the direction of nanoparticle migration and distorts the velocity, temperature and nanoparticle concentration profiles. Moreover, it is shown that the advantage of nanofluids in heat transfer enhancement is reduced in the presence of a magnetic field. - Highlights: • MHD mixed convection of alumina/water nanofluid inside a vertical annulus. • The effects of nanoparticle migration on rheological and thermophysical characteristics. • The effects of asymmetric heating on nanoparticle migration. • The effects of asymmetric heating on the heat transfer enhancement. • Inclusion of nanoparticles in presence of a magnetic field has a negative effect on performance

  20. Low back pain associated with lumbar disc herniation: role of moderately degenerative disc and annulus fibrous tears

    Science.gov (United States)

    Yang, Hao; Liu, Hui; Li, Zemin; Zhang, Kuibo; Wang, Jianru; Wang, Hua; Zheng, Zhaomin

    2015-01-01

    Lumbar disc herniation is one of the most common spinal degenerative disorders which may lead to low back pain (LBP) and radicular leg pain. However, it remains difficult to diagnose a degenerative herniated disc as the LBP generator in clinical practice. The purpose of this study is to explore the characteristic changes of a herniated disc causing LBP on MRI and to clarify the underlying role of inflammatory mediators and annulus fibrous (AF) tears in LBP generation associated with disc herniation. We prospectively collected intervertebral disc specimens and MRI from 57 single-segment disc herniation patients with radiculopathy. All subjects were grouped according to LBP occurrence or disc degeneration severity for the comparison of inflammatory mediators’ expression and AF tears occurrence (High Intensity Zone, HIZ, on MRI). LBP incidence under circumstances of different degeneration severity with or without HIZ was further analyzed. Both LBP incidence and Inflammatory mediators expression in moderately degenerated group was higher than mildly and severely degenerative groups. HIZ incidence was higher in moderately and severely degenerated groups. LBP incidence in the patients with both moderately degenerated discs and HIZ was 86.7%, much higher than the rest of the patient population. In conclusion, the high expression of inflammatory mediators with AF tears causes LBP associated with disc herniation. Moderately degenerative disc with HIZ is MRI morphological change of herniated disc causing LBP, which can be applied to diagnose LBP. PMID:25932092

  1. Protective effect of niacinamide on interleukin-1beta-induced annulus fibrosus type II collagen degeneration in vitro.

    Science.gov (United States)

    Duan, Deyu; Yang, Shuhua; Shao, Zengwu; Wang, Hong; Xiong, Xiaoqian

    2007-02-01

    The protective effect of niacinamide on interleukin-1beta (IL-1beta)-induced annulus fibrosus (AF) type II collagen degeneration in vitro and the mechanism were investigated. Chiba's intervertebral disc (IVD) culture models in rabbits were established and 48 IVDs from 12 adult Japanese white rabbits were randomly divided into 4 groups: normal control group, niacinamide-treated group, type II collagen degneration group (IL-1beta) and treatment group (niacinamide+IL-1beta). After culture for one week, AFs were collected for inducible nitric oxide synthase (iNOS), cysteine containing aspartate specific protease-3 (Caspase-3) and type II collagen immunohistochemical examination, and type II collagen reverse transcription polymerase chain reaction (RT-PCR). The results showed that rate of iNOS positive staining AF cells in the 4 groups was 17.6%, 10.9%, 73.9% and 19.3% respectively. The positive rate in treatment group was significantly lower than in the type II collagen degeneration group (Pniacinamide could effectively inhibit IL-1beta stimulated increase of iNOS and Caspase-3 in AF, and alleviate IL-1beta-caused destruction and synthesis inhibition of type II collagen. Niacinamide is of potential for clinical treatment of IVD degeneration.

  2. Investigation of the influence of radial grooves on the flow in an eccentrically deposited annulus using CFD numerical simulation

    Directory of Open Access Journals (Sweden)

    Bojko Marian

    2014-03-01

    Full Text Available This paper evaluates the influence of radial grooves in the eccentrically deposited annulus using by mathematical modeling of fluid flow through each grooves. The inner cylinder (rotor is eccentrically deposited and its movement is composed of two movements (rotation and precession. The outer cylinder is stationary and has radial grooves. In the first phase is defined a mathematical model of the flow, which is then applied to the 3D model of narrow gap with radial grooves. In this paper are present several variants of the computational domain with regard to the number of radial grooves. Based on the results of numerical simulations are evaluated basic variables such as pressure and velocity. There are also evaluated radial force (Fr and axial force (Fa acting on the rotor for different boundary conditions (different speeds of rotation and precession. Subsequently, the pressure gradients (Δp are evaluated between the radial grooves for different computational domain. Results are compared to variant of narrow gap without radial grooves. Numerical simulation is realized in the program system ANSYS Fluent.

  3. Transient critical heat flux under flow coast-down in vertical annulus with non-uniform heat flux distribution

    International Nuclear Information System (INIS)

    Moon, S.K.; Chun, S.Y.; Choi, K.Y.; Yang, S.K.

    2001-01-01

    An experimental study on transient critical heat flux (CHF) under flow coast-down has been performed for water flow in a non-uniformly heated vertical annulus under low flow and a wide range of pressure conditions. The objectives of this study are to systematically investigate the effect of the flow transient on the CHF and to compare the transient CHF with steady state CHF. The transient CHF experiments have been performed for three kinds of flow transient modes based on the coast-down data of the Kori 3/4 nuclear power plant reactor coolant pump. Most of the CHFs occurred in the annular-mist flow regime. Thus, it means that the possible CHF mechanism might be the liquid film dryout in the annular-mist flow regime. For flow transient mode with the smallest flow reduction rate, the time-to-CHF is the largest. At the same inlet subcooling, system pressure and heat flux, the effect of the initial mass flux on the critical mass flux can be negligible. However, the effect of the initial mass flux on the time-to-CHF becomes large as the heat flux decreases. Usually, the critical mass flux is large for slow flow reduction. There is a pressure effect on the ratio of the transient CHF data to steady state CHF data. Some conventional correlations show relatively better CHF prediction results for high system pressure, high quality and slow transient modes than for low system pressure, low quality and fast transient modes. (author)

  4. Combined Use of High Radiofrequency Disk Ablation, Annulus Modulation, and Manual Nucleotomy in a Patient with Extruded Disk Herniation.

    Science.gov (United States)

    Beyaz, Serbülent Gökhan; İnanmaz, Mustafa Erkan; Zengin, Ezgi Şen; Ülgen, Ali Metin

    2016-06-01

    Different minimally invasive procedures are used to treat lumbar disk herniation. It is important to differentiate these techniques due to their specific effects and the disparate technical issues associated with each. This report describes a successful case involving the use of mechanical decompression in conjunction with radiofrequency ablation to treat a patient with pain and neurological deficits due to an extruded disk hernia. A 43-year-old male had magnetic resonance imaging (MRI) demonstrating an extruded disk herniation in the left foraminal region, compression at the left spinal nerve root, and obliteration of the left foraminal entrance of the L5-S1 distribution. In the operating room, sufficient disk material was removed using grasping forceps, and then, the Disc-FX system with a Trigger-Flex probe (Elliquence, Baldwin, NY, U.S.A.) was inserted. Modulation of the annulus was performed in bipolar hemo mode, and nucleus ablation was conducted in bipolar turbo mode within a 1.7-MHz frequency range. Among the available minimally invasive techniques, newly developed technologies may become important treatment options if they enable faster rehabilitation, lower rates of recurrence, shorter hospital stays, and reduced medical costs. © 2016 World Institute of Pain.

  5. A Novel Dynamic Model for Predicting Pressure Wave Velocity in Four-Phase Fluid Flowing along the Drilling Annulus

    Directory of Open Access Journals (Sweden)

    Xiangwei Kong

    2015-01-01

    Full Text Available A dynamic pressure wave velocity model is presented based on momentum equation, mass-balance equation, equation of state, and small perturbation theory. Simultaneously, the drift model was used to analyze the flow characteristics of oil, gas, water, and drilling fluid multiphase flow. In addition, the dynamic model considers the gas dissolution, virtual mass force, drag force, and relative motion of the interphase as well. Finite difference and Newton-Raphson iterative are introduced to the numerical simulation of the dynamic model. The calculation results indicate that the wave velocity is more sensitive to the increase of gas influx rate than the increase of oil/water influx rate. Wave velocity decreases significantly with the increase of gas influx. Influenced by the pressure drop of four-phase fluid flowing along the annulus, wave velocity tends to increase with respect to well depth, contrary to the gradual reduction of gas void fraction at different depths with the increase of backpressure (BP. Analysis also found that the growth of angular frequency will lead to an increase of wave velocity at low range. Comparison with the calculation results without considering virtual mass force demonstrates that the calculated wave velocity is relatively bigger by using the presented model.

  6. Right heart chamber geometry and tricuspid annulus morphology in patients undergoing mitral valve repair with and without tricuspid valve annuloplasty.

    Science.gov (United States)

    Tamborini, Gloria; Fusini, Laura; Muratori, Manuela; Gripari, Paola; Ghulam Ali, Sarah; Fiorentini, Cesare; Pepi, Mauro

    2016-06-01

    According to current recommendations, patients could benefit from tricuspid valve (TV) annuloplasty at the time mitral valve (MV) surgery if tricuspid regurgitation is severe or if tricuspid annulus (TA) dilatation is present. Therefore, an accurate pre-operative echocardiographic study is mandatory for left but also for right cardiac structures. Aims of this study are to assess right atrial (RA), right ventricular (RV) and TA geometry and function in patients undergoing MV repair without or with TV annuloplasty. We studied 103 patients undergoing MV surgery without (G1: 54 cases) or with (G2: 49 cases) concomitant TV annuloplasty and 40 healthy subjects (NL) as controls. RA, RV and TA were evaluated by three-dimensional (3D) transthoracic echocardiography. Comparing the pathological to the NL group, TA parameters and 3D right chamber volumes were significantly larger. RA and RV ejection fraction and TA% reduction were lower in pathological versus NL, and in G2 versus G1. In pathological patients, TA area positively correlated to systolic pulmonary pressure and negatively with RV and RA ejection fraction. Patients undergoing MV surgery and TV annuloplasty had an increased TA dimensions and a more advanced remodeling of right heart chambers probably reflecting an advanced stage of the disease.

  7. Structural equivalence in the transcribed spacers of pre-rRNA transcripts in Schizosaccharomyces pombe.

    Science.gov (United States)

    Lalev, A I; Nazar, R N

    1999-08-01

    The structure of the internal transcribed spacer 2 (ITS2) in Schizosaccharomyces pombe was re-evaluated with respect to phylogenetically conserved features in yeasts, features in other transcribed spacer regions as well as the binding of transacting factors which potentially play a role in ribosomal maturation. Computer analyses and probes for nuclease protection indicate a very simple core structure consisting of a single extended hairpin which includes the interacting termini of the mature 5.8S and 25S rRNAs. Comparisons with ITS2 sequences in greatly diverging organisms indicate that the same feature also can be recognized. This is especially clear in organisms that contain very short sequences in which the putative structures are much less ambiguous. Diversity between organisms is the result of changes in hairpin length as well as the addition of branched helices. Protein binding and gel retardation studies with the S.pombe ITS2 further indicate that, as observed in the 3" external transcribed spacer (ETS) and ITS1 regions, the extended hairpin is not only the site of intermediate RNA cleavage during rRNA processing but also a site for specific interactions with one or more soluble factors. Taken together with other analyses on transcribed spacer regions, the present data suggest that the spacer regions all may act in a similar fashion, not only to organize the maturing terminal sequences, but also serve to organize specific soluble factors possibly acting with snoRNAs or in a manner which is analogous with that of the free snoRNPs.

  8. Neoleptonema yongpilii E.-Y. Lee & I.K. Lee, gen. et sp. nov. (Phaeophyceae), based on morphological characters and RuBisCO spacer sequences

    DEFF Research Database (Denmark)

    Lee, E.-Y.; Pedersen, Poul Møller; Lee, I.K.

    2002-01-01

    Elachistaceae, Neoleptonema yongpilii gen. et sp. nov., phylogenetic relationships, plurilocular sporangia, RuBisCO spacer sequences......Elachistaceae, Neoleptonema yongpilii gen. et sp. nov., phylogenetic relationships, plurilocular sporangia, RuBisCO spacer sequences...

  9. Numerical Study of Laminar Forced Convection of Water/Al2o3 Nanofluid in an Annulus with Constant Wall Temperature

    Directory of Open Access Journals (Sweden)

    Amin Kashani

    2013-04-01

    Full Text Available Laminar forced convection of a nanofluid consisting of water and Al2O3 in a horizontal annulus has been studied numerically. Two-phase mixture model has been used to investigate thermal behaviors of the nanofluid over constant temperature thermal boundary condition and with different volume concentration of nanoparticles. Comparisons with previously published experimental and analytical works on flow behavior in horizontal annulus show good agreements between the results as volume fraction is zero. In general convective heat transfer coefficient increases with nanoparticle concentration. ABSTRAK: Kertaskerja ini mengkaji secara numerik olakan paksa bendalir lamina yang menganduangi air dan Al2O3 didalam anulus mendatar. Model campuran dua fasa digunakan bagi mengkaji tingkah laku haba bendalir nano pada keadaan suhu malar dengan kepekatan nanopartikel berbeza. Perbandingan dengan karya eksperimen dan analitikal yang telah diterbitkan menunjukkan bahawa kelakuan aliran didalm anulus mendatar adalah baik apabila pecahan isipadu adalah sifar. Pada amnya, pekali pemindahan haba olakan meningkat dengan kepekatan nanopartikel. KEYWORDS: nanofluid; volume concentration; heat transfer enhancement; laminar flow convection; annulus

  10. Unsteady heat transfer combined with thermal radiation along with consideration of temperature-dependent properties and turbulent flow through a thermal entrance region of a concentric annulus and a circular tube

    OpenAIRE

    Kawachi, Shigehiro; Koshin, Haruo; Kurima, Junji; Murakawa, Katsuhisa

    1980-01-01

    The turbulent flow of steam moving through the thermal entrance region of a concentric annulus and a circular tube, is heated by an inner pipe wall of the annulus and the circular tube wall, respectively. An analysis of this was made so as to study unsteady heat transfer combined with thermal radiation and turbulent flow. At the time this study was carried out, we took into consideration the influence of temperature-dependent thermophysical properties, and restricted ourselves to the opticall...

  11. Mobile Semiotics - signs and mobilities

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    This paper is about how to comprehend the mobile condition of contemporary life with a particular view to the signifying dimension of the environment and its ‘readability’. The paper explores the potentials of semiotics and its relationship to the new mobilities literature. The theoretical scope...... is therefore an attempt to mobilize semiotics by drawing on a central body of theory within and adjacent to the discipline. For instance the founding works of C. S. Peirce will be related to the contemporary notions of ‘geosemiotics’ by Scollon & Scollon. The paper’s theoretical claim is that semiotics hold...... a potential for mobilities studies if the awareness of seeing the environment as a semiotic layer and system can be sensitized to the insights of the ‘mobilities turn’. Empirically the paper tentatively explores the usefulness of a mobile semiotics approach to cases such as street signage, airport design...

  12. Mobile phones and mobile communication

    DEFF Research Database (Denmark)

    Ling, Richard; Donner, Jonathan

    With staggering swiftness, the mobile phone has become a fixture of daily life in almost every society on earth. In 2007, the world had over 3 billion mobile subscriptions. Prosperous nations boast of having more subscriptions than people. In the developing world, hundreds of millions of people who...... could never afford a landline telephone now have a mobile number of their own. With a mobile in our hand many of us feel safer, more productive, and more connected to loved ones, but perhaps also more distracted and less involved with things happening immediately around us. Written by two leading...... researchers in the field, this volume presents an overview of the mobile telephone as a social and cultural phenomenon. Research is summarized and made accessible though detailed descriptions of ten mobile users from around the world. These illustrate popular debates, as well as deeper social forces at work...

  13. Patterns of major divergence between the internal transcribed spacers of ribosomal DNA in Xenopus borealis and Xenopus laevis, and of minimal divergence within ribosomal coding regions.

    OpenAIRE

    Furlong, J C; Maden, B E

    1983-01-01

    We have determined the nucleotide sequences of the two internal transcribed spacers, the adjacent ribosomal coding sequences and the boundary between the external transcribed spacer and the 18S coding sequence in a cloned ribosomal transcription unit from Xenopus borealis. The transcribed spacers differ very extensively from those of X. laevis. Nevertheless, embedded in the internal transcribed spacers are several short sequence elements which are identical between the two species. These cons...

  14. Mobile Usability

    DEFF Research Database (Denmark)

    Aryana, Bijan; Clemmensen, Torkil

    2013-01-01

    In this article, a country specific comparative mobile usability study is presented, using Iran and Turkey as the two chosen emerging/emergent nation exemplars of smartphone usage and adoption. In a focus group study, three mobile applications were selected by first-time users of smartphones...

  15. Mobile phone

    International Nuclear Information System (INIS)

    2009-01-01

    Almost the entire Norwegian population has cell phone. The usefulness of the cell phone is great, but can use a mobile phone to health or discomfort? How can exposure be reduced? NRPA follows research and provides advice on mobile phone use. (AG)

  16. Urban Mobility

    DEFF Research Database (Denmark)

    2017-01-01

    This anthology is the proceedings publication from the 2015 NAF Symposium in Malmö, Sweden. The aim of the 2015 NAF Symposium “Urban Mobility – Architectures, Geographies and Social Space” was to facilitate a cross-disciplinary discussion on urban mobility in which the juxtaposition of different...

  17. Mobile Clouds

    DEFF Research Database (Denmark)

    Fitzek, Frank; Katz, Marcos

    users in very different ways and for various purposes. The book provides many stimulating examples of resource-sharing applications. Enabling technologies for mobile clouds are also discussed, highlighting the key role of network coding. Mobile clouds have the potential to enhance communications...... examples of mobile clouds applications, based on both existing commercial initiatives as well as proof-of-concept test-beds. Visions and prospects are also discussed, paving the way for further development. As mobile networks and social networks become more and more reliant on each other, the concept...... of resource sharing takes a wider and deeper meaning, creating the foundations for a global real-time multidimensional resource pool, the underlying infrastructure for shareconomy. Above all, this is an inspiring book for anyone who is concerned about the future of wireless and mobile communications networks...

  18. Staging Mobilities

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    In recent years, the social sciences have taken a “mobilities turn.” There has been a developing realisation that mobilities do not “just happen.” Mobilities are carefully and meticulously designed, planned and staged (from above). However, they are equally importantly acted out, performed and li......, the book asks: what are the physical, social, technical, and cultural conditions to the staging of contemporary urban mobilities?...... that mobility is more than movement between point A and B. It explores how the movement of people, goods, information, and signs influences human understandings of self, other and the built environment. Moving towards a new understanding of the relationship between movement, interaction and environments...

  19. Mobilities Design

    DEFF Research Database (Denmark)

    Jensen, Ole B.; Lanng, Ditte Bendix

    2016-01-01

    Contemporary society is marked and defined by the ways in which mobile goods, bodies, vehicles, objects, and data are organized, moved and staged. On the backgound of the ‘mobilities turn’ (for short review paper on this see; Sheller 2011, Vannini 2010) this paper proposes a further development....... There is a need for research targeting the material, physical and design-oriented dimensions of the multiple mobilities from the local to the global. Despite its cross-disciplinary identity the ‘mobilities turn’ has not sufficiently capitalized from the potential in exploring issues of material design...... of life’ for billions of people in the everyday life. This paper is structured in three parts. After the general introduction we present the mobilities theory perspective of ‘staging mobilities’ and connects this to the empirical phenomenon of parking lots and their design. The paper ends in section three...

  20. Mobile Lexicography

    DEFF Research Database (Denmark)

    Køhler Simonsen, Henrik

    2015-01-01

    are already mobile – but lexicography is not yet fully ready for the mobile challenge, mobile users and mobile user situations. The article is based on empirical data from two surveys comprising 10 medical doctors, who were asked to look up five medical substances with the medical dictionary app Medicin.......dk and five students, who were asked to look up five terms with the dictionary app Gyldendal Engelsk-Dansk. The empirical data comprise approximately 15 hours of recordings of user behavior, think-aloud data and interview data. The data indicate that there is still much to be done in this area...... and that lexicographic innovation is needed. A new type of users, new user situations and new access methods call for new lexicographic solutions, and this article proposes a six-pointed hexagram model, which can be used during dictionary app design to lexicographically calibrate the six dimensions in mobile...

  1. Mobile probes

    DEFF Research Database (Denmark)

    Ørngreen, Rikke; Jørgensen, Anna Neustrup; Noesgaard, Signe Schack

    2016-01-01

    to in an interview. This method provided valuable insight into the contextual use, i.e. how did the online resource transfer to the work practice. However, the research team also found that mobile probes may provide the scaffolding necessary for individual and peer learning at a very local (intra-school) community...... level. This paper is an initial investigation of how the mobile probes process proved to engage teachers in their efforts to improve teaching. It also highlights some of the barriers emerging when applying mobile probes as a scaffold for learning.......A project investigating the effectiveness of a collection of online resources for teachers' professional development used mobile probes as a data collection method. Teachers received questions and tasks on their mobile in a dialogic manner while in their everyday context as opposed...

  2. Mobility Challenges

    DEFF Research Database (Denmark)

    Jensen, Ole B.; Lassen, Claus

    2011-01-01

    This article takes point of departure in the challenges to understand the importance of contemporary mobility. The approach advocated is a cross-disciplinary one drawing on sociology, geography, urban planning and design, and cultural studies. As such the perspective is to be seen as a part...... of the so-called ‘mobility turn’ within social science. The perspective is illustrative for the research efforts at the Centre for Mobility and Urban Studies (C-MUS), Aalborg University. The article presents the contours of a theoretical perspective meeting the challenges to research into contemporary urban...... mobilities. In particular the article discusses 1) the physical city, its infrastructures and technological hardware/software, 2) policies and planning strategies for urban mobility and 3) the lived everyday life in the city and the region....

  3. Restricted Mobilities

    DEFF Research Database (Denmark)

    Nielsen, Mette; Lassen, Claus

    2012-01-01

    communities and shopping centres through mobility lenses. The article shows how different mobility systems enable and restrict the public access to private-public spaces, and it points out that proprietary communities create an unequal potential for human movement and access in the city. The main argument......Privatisation of public spaces in the contemporary city has increased during the last decades but only few studies have approached this field from a mobility perspective. Therefore the article seeks to rectify this by exploring two Australian examples of private spaces in the city; gated...... and stratification mechanisms. In conclusion the article therefore suggests that future urban research and planning also needs a mobile understanding of spaces in the cities and how different mobility systems play an important role to sustain the exclusiveness that often characterises the private/public spaces...

  4. Finite element modeling of stress distribution in intervertebral spacers of different surface geometries.

    Science.gov (United States)

    Lee, Jae Hyup; Baek, Myong-Hyun; Kim, Young Eun; Seo, Jun-Hyuk; Song, Dong Ryul; Ryu, Hyun-Seung; Lee, Choon-Ki; Chang, Bong-Soon

    2013-11-01

    Intervertebral disc spacers using bioactive ceramics have been used to treat degenerative spinal disease. Tooth-shaped spacers are commonly used to prevent migration, but there is a possibility of fracture when inserted or after insertion. Intervertebral disc spacers with either an isosceles triangle-shaped tooth (T1) or a right triangle-shaped tooth (T2) were used as a control group. The design factors for the experimental group were modified to prevent fractures induced by stress concentration, and the surfaces of the spacers were designed as either an isosceles triangle-shaped valley (V1) or a right triangle-shaped valley (V2). Linear analysis using finite element model (FEM) was performed, and Von Mises stress distribution was calculated by applying 1000 N of uniformly distributed load. Samples of the V2 design were made with bioactive glass-ceramics (BGS-7) and evaluated for compressive strength, fatigue degree, and impact strength. Von Mises stress was highest at the first tooth from the posterior side for the control group and at the center for the experimental group. Compared with the control group, the experimental group showed 18.4% and 82.5% reduction (V1 vs. T1 and V2 vs. T2, respectively) in the maximum stress at the bottom of the valleys. The FEM analysis revealed that the V2 design had the most even load distribution. The V2 samples with bioactive glass-ceramics were evaluated for compressive strength, and all six samples were not fractured up to 24 000 N. However, the average impact strength was 19.42 kN, suggesting that momentary force caused damage at a lower load than compression with a steady speed. The BGS-7 intervertebral disc spacer with V2 design was not fractured during the fatigue test at maximum pressure of 8000 N, R ≥10, 5 Hz, and 5 million cycles. These data confirm that the BGS-7 spacer with the V2 design may be clinically applicable. Collectively, the modified surface geometry of the experimental group significantly lowered Von

  5. Mechanical evaluation of hip cement spacer reinforcement with stainless steel Kirschner wires, titanium and carbon rods, and stainless steel mesh.

    Science.gov (United States)

    Kaku, Nobuhiro; Tabata, Tomonori; Tsumura, Hiroshi

    2015-04-01

    In two-stage treatments for infections after total hip arthroplasty, antibiotic-loaded cement spacers help treat the infection by antibiotic elution and prevent contraction. However, such spacers are weak and may fracture while awaiting replacement, impairing functionality. We evaluated whether a Kirschner wire (K-wire) mounted into the spacer reinforced its strength along with the effects of the reinforcing material, position, and intensity. Spacers without reinforcing materials constituted the control group. As reinforcing materials, stainless steel K-wires (diameters 3 and 6 mm), titanium alloy and carbon fibers (diameter 3.175 mm), and stainless steel meshes (inner and outer diameters, 6 and 9 mm, respectively) were inserted into the spacer mold before filling with cement. The spacers complied with ISO 7206-4; a compressive load was applied using a testing machine with a velocity of 25.4 mm/min, and the maximum load was recorded. We used 1-3 K-wires positioned on the medial side, lateral side, neck only, and stem only and tested 3 specimens for each condition. The control group withstood the highest load. Stainless steel was the strongest material; 3-mm K-wires in the neck and lateral side withstood a higher load. The computed tomography (CT) imaging revealed a cavity between the K-wires and cement. When K-wires were inserted along the whole length, despite cement fractures, continuity was maintained because of the reinforcing materials. It is difficult to improve the reinforcing strength of spacers using K-wires; however, K-wires prevented dislocation of cement spacer fragments, which can help prevent contraction and facilitate spacer removal during replacement.

  6. On the Origin of Reverse Transcriptase-Using CRISPR-Cas Systems and Their Hyperdiverse, Enigmatic Spacer Repertoires

    Directory of Open Access Journals (Sweden)

    Sukrit Silas

    2017-07-01

    Full Text Available Cas1 integrase is the key enzyme of the clustered regularly interspaced short palindromic repeat (CRISPR-Cas adaptation module that mediates acquisition of spacers derived from foreign DNA by CRISPR arrays. In diverse bacteria, the cas1 gene is fused (or adjacent to a gene encoding a reverse transcriptase (RT related to group II intron RTs. An RT-Cas1 fusion protein has been recently shown to enable acquisition of CRISPR spacers from RNA. Phylogenetic analysis of the CRISPR-associated RTs demonstrates monophyly of the RT-Cas1 fusion, and coevolution of the RT and Cas1 domains. Nearly all such RTs are present within type III CRISPR-Cas loci, but their phylogeny does not parallel the CRISPR-Cas type classification, indicating that RT-Cas1 is an autonomous functional module that is disseminated by horizontal gene transfer and can function with diverse type III systems. To compare the sequence pools sampled by RT-Cas1-associated and RT-lacking CRISPR-Cas systems, we obtained samples of a commercially grown cyanobacterium—Arthrospira platensis. Sequencing of the CRISPR arrays uncovered a highly diverse population of spacers. Spacer diversity was particularly striking for the RT-Cas1-containing type III-B system, where no saturation was evident even with millions of sequences analyzed. In contrast, analysis of the RT-lacking type III-D system yielded a highly diverse pool but reached a point where fewer novel spacers were recovered as sequencing depth was increased. Matches could be identified for a small fraction of the non-RT-Cas1-associated spacers, and for only a single RT-Cas1-associated spacer. Thus, the principal source(s of the spacers, particularly the hypervariable spacer repertoire of the RT-associated arrays, remains unknown.

  7. Similar Results in Children with Asthma for Steady State Pharmacokinetic Parameters of Ciclesonide Inhaled with or without Spacer

    Directory of Open Access Journals (Sweden)

    H. Boss

    2010-01-01

    Full Text Available Background Ciclesonide is an inhaled corticosteroid administered by a metered dose inhaler (MDI to treat bronchial asthma. After inhalation, the inactive ciclesonide is converted by esterases in the airways to active metabolite desisobutyryl-ciclesonide (des-CIC. Aim To compare the pharmacokinetic (PK parameters of des-CIC in children after administration of therapeutic dose of ciclesonide with and without spacer (AeroChamber Plus™. Methods Open-label, 3 period, cross over, repeated dose, PK study in 37 children with mild to moderate stable asthma (age: 6–11 y; body weight: 20–53 kg. During each 7-day treatment period, ciclesonide was inhaled once in the morning: A 160 μg MDI with spacer, B 80 μg MDI with spacer, and C 160 μg MDI without spacer. Serum PK parameters of ciclesonide and des-CIC were determined on Day 7 of each period. The primary PK parameters were the AUC τ and C max for des-CIC. Results Inhaling ciclesonide with spacer led to a dose proportional systemic exposure (AUC τ of des-CIC (0.316 μg*h/L for 80 μg and 0.663 μg*h/L for 160 μg. The dose-normalized systemic exposure for des-CIC (based on AUC τ was 27% higher after inhalation of ciclesonide 80 μg or 160 μg with spacer than without spacer; the corresponding C max values for des-CIC were, respectively, 63% and 55% higher with spacer. No clinically relevant abnormalities or adverse drug reactions were observed. Conclusions Inhalation of therapeutic ciclesonide dose with spacer led to a slight increase in the systemic exposure of des-CIC, which does not warrant dose adjustment.

  8. A comparative evaluation of application techniques of a paint-on die spacer in grooves: an in vitro study.

    Science.gov (United States)

    Vaishali, K; Prasad, D Krishna; Shetty, Manoj

    2013-12-01

    The use of paint-on die spacer to improve the seating of casting has become quite popular in the recent years. The generally accepted range of paint-on die spacer is approximately 20-40 μm, which suggests a range of tolerance. The painting of the retentive grooves with die spacer has always been a subject of debate. The primary purpose of this study was to determine if there was a tendency for the paint-on die spacer to accumulate in grooves of tooth preparation in sufficient thickness to exceed this accepted range of tolerance when applied using two different techniques. Eight die stone blocks with three grooves each were prepared. Half the samples were painted in unidirectional method and the other halves were painted using the haphazard method of application. The thickness of the die spacer was measured at different positions using 200× magnification and the mean and standard deviations were calculated. On analysis it was seen that the thickness of the paint-on die spacer in grooves was in the range of 20-40 μm for unidirectional method of application, whereas in haphazard method of application the thickness of the paint-on die spacer was in the range of 28-132 μm. From the above study it was concluded that the method of application influenced the thickness of the paint-on die spacer. The recommended thickness of the die spacer was achieved on unidirectional method of application.

  9. Numerical study of methanol–steam reforming and methanol–air catalytic combustion in annulus reactors for hydrogen production

    International Nuclear Information System (INIS)

    Chein, Reiyu; Chen, Yen-Cho; Chung, J.N.

    2013-01-01

    Highlights: ► Performance of mini-scale integrated annulus reactors for hydrogen production. ► Flow rates fed to combustor and reformer control the reactor performance. ► Optimum performance is found from balance of flow rates to combustor and reformer. ► Better performance can be found when shell side is designed as combustor. -- Abstract: This study presents the numerical simulation on the performance of mini-scale reactors for hydrogen production coupled with liquid methanol/water vaporizer, methanol/steam reformer, and methanol/air catalytic combustor. These reactors are designed similar to tube-and-shell heat exchangers. The combustor for heat supply is arranged as the tube or shell side. Based on the obtained results, the methanol/air flow rate through the combustor (in terms of gas hourly space velocity of combustor, GHSV-C) and the methanol/water feed rate to the reformer (in terms of gas hourly space velocity of reformer, GHSV-R) control the reactor performance. With higher GHSV-C and lower GHSV-R, higher methanol conversion can be achieved because of higher reaction temperature. However, hydrogen yield is reduced and the carbon monoxide concentration is increased due to the reversed water gas shift reaction. Optimum reactor performance is found using the balance between GHSV-C and GHSV-R. Because of more effective heat transfer characteristics in the vaporizer, it is found that the reactor with combustor arranged as the shell side has better performance compared with the reactor design having the combustor as the tube side under the same operating conditions.

  10. Effect of orientation and targeted extracellular matrix degradation on the shear mechanical properties of the annulus fibrosus.

    Science.gov (United States)

    Jacobs, Nathan T; Smith, Lachlan J; Han, Woojin M; Morelli, Jeffrey; Yoder, Jonathon H; Elliott, Dawn M

    2011-11-01

    The intervertebral disc experiences combinations of compression, torsion, and bending that subject the disc substructures, particularly the annulus fibrosus (AF), to multidirectional loads and deformations. Combined tensile and shear loading is a particularly important loading paradigm, as compressive loads place the AF in circumferential hoop tension, and spine torsion or bending induces AF shear. Yet the anisotropy of AF mechanical properties in shear, as well as important structure-function mechanisms governing this response, are not well-understood. The objective of this study, therefore, was to investigate the effects of tissue orientation and enzymatic degradation of glycosaminoglycan (GAG) and elastin on AF shear mechanical properties. Significant anisotropy was found: the circumferential shear modulus, Gθz, was an order of magnitude greater than the radial shear modulus, Grθ. In the circumferential direction, prestrain significantly increased the shear modulus, suggesting an important role for collagen fiber stretch in shear properties for this orientation. While not significant and highly variable, ChABC treatment to remove GAG increased the circumferential shear modulus compared to PBS control (p=0.15). Together with the established literature for tensile loading of fiber-reinforced GAG-rich tissues, the trends for changes in shear modulus with ChABC treatment reflect complex, structure-function relationships between GAG and collagen that potentially occur over several hierarchical scales. Elastase digestion did not significantly affect shear modulus with respect to PBS control; further contributing to the notion that circumferential shear modulus is dominated by collagen fiber stretch. The results of this study highlight the complexity of the structure-function relationships that govern the mechanical response of the AF in radial and circumferential shear, and provide new and more accurate data for the validation of material models and tissue

  11. Beta1 integrin inhibits apoptosis induced by cyclic stretch in annulus fibrosus cells via ERK1/2 MAPK pathway.

    Science.gov (United States)

    Zhang, Kai; Ding, Wei; Sun, Wei; Sun, Xiao-jiang; Xie, You-zhuan; Zhao, Chang-qing; Zhao, Jie

    2016-01-01

    Low back pain is associated with intervertebral disc degeneration (IVDD) due to cellular loss through apoptosis. Mechanical factors play an important role in maintaining the survival of the annulus fibrosus (AF) cells and the deposition of extracellular matrix. However, the mechanisms that excessive mechanical forces lead to AF cell apoptosis are not clear. The present study was to look for how AF cells sense mechanical changes. In vivo experiments, the involvement of mechanoreceptors in apoptosis was examined by RT-PCR and/or immunoblotting in the lumbar spine of rats subjected to unbalanced dynamic and static forces. In vitro experiments, we investigated apoptotic signaling pathways in untransfected and transfected AF cells with the lentivirus vector for rat β1 integrin overexpression after cyclic stretch. Apoptosis in AF cells was assessed using flow cytometry, Hoechst 33258 nuclear staining. Western blotting was used to analyze expression of β1 integrin and caspase-3 and ERK1/2 MAPK signaling molecules. In the rat IVDD model, unbalanced dynamic and static forces induced apoptosis of disc cells, which corresponded to decreased expression of β1 integrin. Cyclic stretch-induced apoptosis in rat AF cells correlated with the activation of caspase-3 and with decreased levels of β1 integrin and the phosphorylation levels of ERK1/2 activation level. However, the overexpression of β1 integrin in AF cells ameliorated cyclic stretch-induced apoptosis and decreased caspase-3 activation. Furthermore, ERK1/2-specific inhibitor promotes apoptosis in vector β1-infected AF cells. These results suggest that the disruption of β1 integrin signaling may underlie disc cell apoptosis induced by mechanical stress. Further work is necessary to fully elucidate the pathophysiological mechanisms that underlie IVDD caused by unbalanced dynamic and static forces.

  12. Going Mobile?

    DEFF Research Database (Denmark)

    Tallon, Loic; Froes, Isabel Cristina G.

    2011-01-01

    If the future is mobile, how is the museum community developing within that future? What are the challenges museums face within it? In which directions should we be seeking to evolve our collective knowledge share? It was to gain observations on questions such as these that the 2011 Museums...... & Mobile survey was developed: 660 museum professionals responded. In this paper the authors highlight nine survey observations that they believe are important to the museum community’s increased understanding of and continued progress within mobile interpretation....

  13. Accentual mobility

    DEFF Research Database (Denmark)

    Olander, Thomas Kristoffer

    slaviske mobile accentparadigmer i høj grad stemmer overens med hinanden, er det sandsynligt at accentmobiliteten i de to sproggrupper går tilbage til et fælles udgangspunkt. Formålet med afhandlingen er at bestemme den urindoeuropæiske baggrund for de baltoslaviske mobile accentparadigmer. I de...... paradigmatiske accent i urbaltoslavisk på grundlag af materiale fra de tre baltiske sprog og urslavisk. I kapitel IV foretages af en undersøgelse af den foreslåede accentlov ud fra en sammenligning af de rekonstruerede urindoeuropæiske endelser og de tilsvarende former i de urbaltoslaviske mobile...

  14. Spacer layer effect and microstructure on multi-layer [NdFeB/Nb]n films

    International Nuclear Information System (INIS)

    Tsai, J.-L.; Yao, Y.-D.; Chin, T.-S.; Kronmueller, H.

    2002-01-01

    Spacer layer effect on multi-layer [NdFeB/Nb] n films has been investigated from the variation of magnetic properties and microstructure of the films. From a HRTEM cross-section view observation, the average grain size of [NdFeB/Nb] n multi-layers was controlled by both annealing temperature and thickness of NdFeB layer. Selected area diffraction pattern indicated that the structure of Nb spacer layer was amorphous. The grain size and coercivity of [NdFeB x /Nb] n films change from 50 nm and 16.7 kOe to 167 nm and 9 kOe for films with x=40 nm, n=10 and x=200 nm, n=2, respectively

  15. Synthesis, Characterization and Biological Studies of New Linear Thermally Stable Schiff Base Polymers with Flexible Spacers.

    Science.gov (United States)

    Qureshi, Farah; Khuhawar, Muhammad Yar; Jahangir, Taj Muhammad; Channar, Abdul Hamid

    2016-01-01

    Five new linear Schiff base polymers having azomethine structures, ether linkages and extended aliphatic chain lengths with flexible spacers were synthesized by polycondensation of dialdehyde (monomer) with aliphatic and aromatic diamines. The formation yields of monomer and polymers were obtained within 75-92%. The polymers with flexible spacers of n-hexane were somewhat soluble in acetone, chloroform, THF, DMF and DMSO on heating. The monomer and polymers were characterized by melting point, elemental microanalysis, FT-IR, (1)HNMR, UV-Vis spectroscopy, thermogravimetry (TG), differential thermal analysis (DTA), fluorescence emission, scanning electron microscopy (SEM) and viscosities and thermodynamic parameters measurements of their dilute solutions. The studies supported formation of the monomer and polymers and on the basis of these studies their structures have been assigned. The synthesized polymers were tested for their antibacterial and antifungal activities.

  16. Effect of spacer layer on the magnetization dynamics of permalloy/rare-earth/permalloy trilayers

    International Nuclear Information System (INIS)

    Luo, Chen; Yin, Yuli; Zhang, Dong; Jiang, Sheng; Yue, Jinjin; Zhai, Ya; Du, Jun; Zhai, Hongru

    2015-01-01

    The permalloy/rare-earth/permalloy trilayers with different types (Gd and Nd) and thicknesses of spacer layer are investigated using frequency dependence of ferromagnetic resonance (FMR) measurements at room temperature, which shows different behaviors with different rare earth spacer layers. By fitting the frequency dependence of the FMR resonance field and linewidth, we find that the in-plane uniaxial anisotropy retains its value for all samples, the perpendicular anisotropy remains almost unchanged for different thickness of Gd layer but the values are tailored by different thicknesses of Nd layer. The Gilbert damping is almost unchanged with different thicknesses of Gd; however, the Gilbert damping is significantly enhanced from 8.4×10 −3 to 20.1×10 −3 with 6 nm of Nd and then flatten out when the Nd thickness rises above 6 nm

  17. Multilayer barrier films comprising nitrogen spacers between free-standing barrier layers

    Science.gov (United States)

    Granstrom, Jimmy; Villet, Michael; Chatterjee, Tirtha; Gerbec, Jeffrey A.; Jerkunica, Evan; Roy, Anshuman

    2009-08-01

    An encapsulation architecture for organic electronic devices utilizing nitrogen gas-phase spacers between free-standing barrier films is demonstrated. The nitrogen spacers act as sinks for permeating H2O and O2, delaying establishment of steady-state chemical potential gradients across the barriers and thereby reducing permeation rates. Water vapor transmission through nitrogen-spaced barriers was measured via the calcium optical transmission test. Substantial reductions in permeation rate were observed for a variety of barrier materials and configurations, suggesting a general and cost-effective approach for improving encapsulation performance. A low-cost polyethylene terephthalate film increases the calcium lifetime of a Cytop™-Kureha structure from 7000 to 12000 min.

  18. Transcriptome changes in STSV2-infected Sulfolobus islandicus REY15A undergoing continuous CRISPR spacer acquisition

    DEFF Research Database (Denmark)

    León-Sobrino, Carlos; Kot, Witold P; Garrett, Roger A

    2016-01-01

    A transcriptome study was performed on Sulfolobus islandicus REY15A actively undergoing CRISPR spacer acquisition from the crenarchaeal monocaudavirus STSV2 in rich and basal media over a 6 day period. Spacer acquisition preceded strong host growth retardation, altered transcriptional activity...... of four different CRISPR-Cas modules and changes in viral copy numbers, and with significant differences in the two media. Transcript levels of proteins involved in the cell cycle were reduced, while those of DNA replication, DNA repair, transcriptional regulation, and some antitoxin-toxin pairs...... and transposases were unchanged or enhanced. Antisense RNAs were implicated in the transcriptional regulation of adaptation and interference modules of the type I-A CRISPR-Cas system and evidence was found for the occurrence of functional coordination between the single CRISPR-Cas adaptation module...

  19. Metagenomic data of fungal internal transcribed spacer from serofluid dish, a traditional Chinese fermented food

    Directory of Open Access Journals (Sweden)

    Peng Chen

    2016-03-01

    Full Text Available Serofluid dish (or Jiangshui, in Chinese, a traditional food in the Chinese culture for thousands of years, is made from vegetables by fermentation. In this work, microorganism community of the fermented serofluid dish was investigated by the culture-independent method. The metagenomic data in this article contains the sequences of fungal internal transcribed spacer (ITS regions of rRNA genes from 12 different serofluid dish samples. The metagenome comprised of 50,865 average raw reads with an average of 8,958,220 bp and G + C content is 45.62%. This is the first report on metagenomic data of fungal ITS from serofluid dish employing Illumina platform to profile the fungal communities of this little known fermented food from Gansu Province, China. The Metagenomic data of fungal internal transcribed spacer can be accessed at NCBI, SRA database accession no. SRP067411.

  20. Development and Manufacture of the Coil End Spacers of the LHC Pre-series Dipoles

    CERN Document Server

    Farina, E; Perini, D; Schiappapietra, A; Seneé, L

    2002-01-01

    The coil end spacers play an important role in the performance of superconducting coils, as their shape and location determine the mechanical stability of the conductors in the coil ends (and hence the overall coil training performance) and the local field quality. The dipole end spacers are often of a size and a geometry difficult to be industrially series manufactured and measured. Efficiency of the production and related costs are a key issue to achieve the required production rate of the LHC main dipoles at an affordable price. For the latter reasons, a design approach integrating state-of-the-art CAD/CAM optimization techniques allowing to considerably decrease design and machining time was implemented. This paper gives examples and describes the design criteria, the computation methods, the machining and measuring procedures adopted to carry out the pre-series production.

  1. Imidacloprid and Thiamethoxam Induced Mutations in Internal Transcribed Spacer 2 (ITS2) of Anopheles stephensi

    OpenAIRE

    Bhinder, Preety; Chaudhry, Asha; Barna, Bhupinder; Kaur, Satvinderjeet

    2012-01-01

    The present article deals with the polymerase chain reaction (PCR)-based genotoxicity evaluation of neonicotinoid pesticides, imidacloprid and thiamethoxam, by using the genome of a mosquito Anopheles stephensi taken as an experimental model. After treatment of the second instar larvae with LC20 of the pesticides for 24 h, the induced nucleotide sequence variations in the internal transcribed spacer 2 (ITS2) of freshly hatched unfed control and treated individuals was studied from the sequenc...

  2. Novel electromagnetic technique for repositioning of coolant tube spacers in CANDU nuclear reactors

    Science.gov (United States)

    Dableh, Joseph H.

    1986-06-01

    A novel electromagnetic technique to reposition the coolant tube spacers in the fuel channels of CANDU nuclear reactors was successfully developed in the fall of 1983 at Ontario Hydro Research Division. The need to reposition dislocated spacers in noncommissioned reactors was discovered subsequent to the rupture of a pressure tube in one reactor at the Pickering Nuclear Generator Station in Ontario. A contributing factor to the failure of the tube was the fact that the annular spacers (garter springs), used to maintain the coaxial configuration between the pressure tube and its surrounding calandria tube, had been displaced longitudinally for a number of years. Subsequent to this finding, it was discovered that a number of garter springs in noncommissioned nuclear reactors were displaced due to vibration induced by various sources during the construction stage. Since the garter springs are not directly accessible by mechanical means, extensive dismantling of the fuel channels would have been necessary to reposition the springs in their designated locations. This paper describes a novel method to reposition the garter springs without dismantling the fuel channels. The method consists of exerting a force on the springs in the direction of the required displacement by applying a large electromagnetic impulse (generated by a 200-kJ capacitor bank) to a drive coil inserted into the pressure tube opposite the spacer. The repositioning of displaced garter springs in five new reactors in Ontario has been carried out successfully in 1984. The saving in reactor repair cost, interest charges, and replacement energy cost was on the order of hundreds of millions of dollars. Equally large benefits and savings will be realized if the need to use this technique in commissioned reactors arises. Also, the related development of strong compact coils and low-resistance pulse power cable have significant implications and advantages in various other applications related to the pulse

  3. Silver-graphene oxide based plasmonic spacer for surface plasmon-coupled fluorescence emission enhancements

    Science.gov (United States)

    Badiya, Pradeep Kumar; Srinivasan, Venkatesh; Sathish Ramamurthy, Sai

    2017-06-01

    We report the application of single layered graphene oxide (SLGO) and silver decorated SLGO (Ag-SLGO) as plasmonic spacer material for obtaining enhanced fluorescence from a Rhodamine 6G (Rh6G) radiating dipole in a surface plasmon-coupled emission platform. To this end, we have decorated SLGO with biphasic silver nanoparticles using an in situ deposition technique to achieve 112-fold fluorescence enhancements.

  4. Photo-induced antiferromagnetic interlayer coupling in Fe superlattices with iron silicide spacers

    Energy Technology Data Exchange (ETDEWEB)

    Mattson, J.E.; Fullerton, E.E.; Kumar, S.; Lee, S.R.; Sowers, C.H.; Grimsditch, M.; Bader, S.D. [Argonne National Lab., IL (United States); Parker, F.T. [California Univ., San Diego, La Jolla, CA (United States). Center for Magnetic Recording Research

    1993-09-01

    Sputtered Fe/FeSi films possessing antiferromagnetic (AF) interlayer coupling at room temperature develop ferromagnetic remanence when cooled below 100K, but the AF coupling can be restored at low temperature by exposure to visible light of sufficient intensity (>10 mW/mm{sup 2}). We attribute these effects to charge carriers in the FeSi spacer layer which, when thermally or photo-generated, are capable of communicating spin information between the Fe layers.

  5. Experimental benchmark data for PWR rod bundle with spacer-grids

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez-Ontiveros, Elvis E. [Nuclear Engineering Department, Texas A and M University, College Station, TX 77843-3133 (United States); Hassan, Yassin A., E-mail: y-hassan@tamu.edu [Nuclear Engineering Department, Texas A and M University, College Station, TX 77843-3133 (United States); Conner, Michael E.; Karoutas, Zeses [Westinghouse Nuclear Fuel, 5801 Bluff Road, Columbia, SC 29209 (United States)

    2012-12-15

    In numerical simulations of fuel rod bundle flow fields, the unsteady Navier-Stokes equations have to be solved in order to determine the time (phase) dependent characteristics of the flow. In order to validate the simulations results, detailed comparison with experimental data must be done. Experiments investigating complex flows in rod bundles with spacer grids that have mixing devices (such as flow mixing vanes) have mostly been performed using single-point measurements. In order to obtain more details and insight on the discrepancies between experimental and numerical data as well as to obtain a global understanding of the causes of these discrepancies, comparisons of the distributions of complete phase-averaged velocity and turbulence fields for various locations near spacer-grids should be performed. The experimental technique Particle Image Velocimetry (PIV) is capable of providing such benchmark data. This paper describes an experimental database obtained using two-dimensional Time Resolved Particle Image Velocimetry (TR-PIV) measurements within a 5 Multiplication-Sign 5 PWR rod bundle with spacer-grids that have flow mixing vanes. One of the unique characteristic of this set-up is the use of the Matched Index of Refraction technique employed in this investigation to allow complete optical access to the rod bundle. This unique feature allows flow visualization and measurement within the bundle without rod obstruction. This approach also allows the use of high temporal and spatial non-intrusive dynamic measurement techniques namely TR-PIV to investigate the flow evolution below and immediately above the spacer. The experimental data presented in this paper includes explanation of the various cases tested such as test rig dimensions, measurement zones, the test equipment and the boundary conditions in order to provide appropriate data for comparison with Computational Fluid Dynamics (CFD) simulations. Turbulence parameters of the obtained data are presented

  6. A new spacer-guided, PCL balancing technique for cruciate-retaining total knee replacement.

    Science.gov (United States)

    Heesterbeek, P J C; Labey, L; Wong, P; Innocenti, B; Wymenga, A B

    2014-03-01

    The goal of this study was to investigate whether a new posterior cruciate ligament (PCL) balancing approach with a spacer technique during total knee arthroplasty (TKA) reproduced the correct tibiofemoral contact point (CP) location. It was hypothesized that it should be possible to adequately balance the PCL with this geometrical technique, obtaining correct position and stability of the medial femoral condyle, independent of insert shape. Nine fresh-frozen full-leg cadaver specimens were used. After native testing, prototype components of a new PCL-retaining implant were implanted using navigation and a bone-referencing technique. After finishing the bone cuts, the spacer technique was used to ascertain balancing of the PCL and the tibial cut was corrected if necessary. Passive and squat motions were performed before and after TKA using a dynamic knee simulator while tibiofemoral kinematics were recorded using six infrared cameras. CPs (native and implant) were calculated as the projections of the femoral condylar centres on the horizontal plane of the tibia. The spacer technique resulted in correct PCL balancing in all specimens. The kinematic patterns of native and replaced knees showed no statistically significant differences in passive and squat motions. The medial CP after TKA was at the same position as in the native knee. No paradoxical sliding forward was seen after TKA, supporting our hypothesis. The spacer technique can be applied by surgeons during PCL-retaining TKA and will lead to good PCL balancing, indicated by a correct CP, no lift-off in flexion and no posterior sag.

  7. Experimental benchmark data for PWR rod bundle with spacer-grids

    International Nuclear Information System (INIS)

    Dominguez-Ontiveros, Elvis E.; Hassan, Yassin A.; Conner, Michael E.; Karoutas, Zeses

    2012-01-01

    In numerical simulations of fuel rod bundle flow fields, the unsteady Navier–Stokes equations have to be solved in order to determine the time (phase) dependent characteristics of the flow. In order to validate the simulations results, detailed comparison with experimental data must be done. Experiments investigating complex flows in rod bundles with spacer grids that have mixing devices (such as flow mixing vanes) have mostly been performed using single-point measurements. In order to obtain more details and insight on the discrepancies between experimental and numerical data as well as to obtain a global understanding of the causes of these discrepancies, comparisons of the distributions of complete phase-averaged velocity and turbulence fields for various locations near spacer-grids should be performed. The experimental technique Particle Image Velocimetry (PIV) is capable of providing such benchmark data. This paper describes an experimental database obtained using two-dimensional Time Resolved Particle Image Velocimetry (TR-PIV) measurements within a 5 × 5 PWR rod bundle with spacer-grids that have flow mixing vanes. One of the unique characteristic of this set-up is the use of the Matched Index of Refraction technique employed in this investigation to allow complete optical access to the rod bundle. This unique feature allows flow visualization and measurement within the bundle without rod obstruction. This approach also allows the use of high temporal and spatial non-intrusive dynamic measurement techniques namely TR-PIV to investigate the flow evolution below and immediately above the spacer. The experimental data presented in this paper includes explanation of the various cases tested such as test rig dimensions, measurement zones, the test equipment and the boundary conditions in order to provide appropriate data for comparison with Computational Fluid Dynamics (CFD) simulations. Turbulence parameters of the obtained data are presented in order to gain

  8. Staying Mobile

    Science.gov (United States)

    ... the most appropriate aid(s). Mobility aids can: Make shopping trips manageable and visits to a museum or ... Association for Driver Rehabilitation Specialists (ADED) Provides an online search tool to locate rehabilitation specialists, certified driver ...

  9. Mobile museology

    DEFF Research Database (Denmark)

    Baggesen, Rikke Haller

    Drawing together perspectives from museology, digital culture studies and fashion theory, this thesis considers changes in and challenges for current - day museums as related to ‘mobile museology’. This concept is developed for and elucidated in the thesis to describe an orientation towards...... the fashionable, the ephemeral, and towards an (ideal) state of change and changeability. This orientation is characterised with the triplet concepts of mobile, mobility, and mobilisation, as related to mobile media and movability; to ‘trans - museal’ mediation; and to the mobilisation of collections, audiences...... and institutional mindsets. The research project’s transdisciplinary and exploratory approach takes inspiration from critical design, minding Latour’s (2004a) call for rethink ing critical approaches in the humanities. Through a creative process, focused on designs for framing fashion in everyday contexts...

  10. Similar rate of infection eradication for functional articulating, prefabricated and custom-made spacers in 2-stage revision of the infected total hip: a literature review.

    Science.gov (United States)

    Veltman, Ewout S; Moojen, Dirk Jan F; Glehr, Mathias; Poolman, Rudolf W

    2016-07-25

    2-stage revision with the use of an antibiotic-loaded interval spacer is therapy of choice in late periprosthetic joint infection for most surgeons. For the spacer, either a prefabricated, functional articulating or custom-made spacer can be used. Little is known about which type of spacer provides optimal outcome after 2-stage revision. The aim of this study was to determine which type of spacer provides the best results, when used in 2-stage revision of an infected THA. We performed a systematic review of the literature to analyse which type of interval spacer provides highest infection eradication rate and best functional outcome after a minimum 2 year follow-up. Exclusion criteria were follow-up of less than 2 years, single-stage revision, or 2-stage revision without use of a spacer. 25 studies were included. Infection eradication rate was similar with rates of 96%, 93% and 95% for the prefabricated-, functional articulating- and custom-made spacers respectively. Functional outcome was scarcely described. Postoperative HHS was 81, 90 and 83 respectively. Functional articulating spacers achieve a comparable rate of infection eradication in the treatment of periprosthetic hip joint infections as compared to preformed or custom-made antibiotic-loaded spacers. There is insufficient evidence concerning rehabilitation and functional outcome after 2-stage revision hip arthroplasty to advocate or discourage the use of either kind of interval spacer.

  11. Procedure for vibration test of the fuel rod supported by spacer grids

    International Nuclear Information System (INIS)

    Choi, Myoung Hwan; Kang, Heung Seok; Yoon, Kyung Ho; Kim, Hyung Kyu; Song, Kee Nam

    2002-07-01

    One of the methods that are used to compare and verify the supporting performance of the spacer grids developed is the vibration characteristic test. In this report there are two aims. One is of the understand of the experimental method and procedure performing the modal testing using I-DEAS TDAS module. The other is the investigation of the vibration behaviors of a dummy fuel rod supported by 8 optimized H type spacer grids. This report describes the method and procedure of modal testing to obtain the vibration characteristics such as amplitudes, natural frequencies and mode shapes of the fuel rod using a shaker, a non-contact gap sensor and an accelerometer. This report provides a test procedure in detail so that anyone can be easily understood and use the I-DEAS TDAS program. The I-DEAS TDAS program related to the modal testing has several tasks including the Modal analysis, Signal Processing et al.. This report includes model preparation to prepare the geometrical model, Signal Processing (Sine/Standard measurement) to acquire the signal, Modal analysis to obtain the frequencies and mode shapes, Correlation to analyze the relation between the test and FE analysis and Post Processing tasks. In addition, this report contains the actual test and analysis data of a dummy fuel rod in length 3847mm supported by 8 optimized H type spacer grids

  12. Finite element analysis of the contact between fuel rod and spacer grid

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyung Kyu; Kim, Young Koon; Kang, Heung Seok; Yoon, Kyung Ho; Song, Kee Nam [Korea Atomic Energy Research Institute, Taejon (Korea)

    1999-01-01

    For the research on the fretting failure problem of nuclear fuel, the contact length and normal stress field are evaluated for the contact between fuel rod and spacer grid by using the Finite Element Method (FEM). An assumption of semi-infiniteness is necessary for applying the Contact Mechanics which is based on the classical theory of elasticity to the present problem. For the contact problem of fuel fretting, the contact mechanical solutions could be utilized well with sufficient accuracy if the contact bodies (i.e., the cladding tube and the spacer grid) can be assumed as semi-infinite bodies. To this end, the contact length evaluated by FEM is discussed together with the relevant research which concerned the effect of dimension for the validity of the assumption of semi-infiniteness. Normal stress profile on the contact is also studied through comparing the theoretical and the FE results. For the analysis of contact problem by FEM, ANSYS code (Version 5.3) is utilized and the geometry is chosen to be the Hertzian (cylinder-to-cylinder), the strip-to-cylinder and the fuel rod/spacer grid contact (strip-to-tube). Present research will be utilized for accessing the fuel fretting problem by FEM together with the theoretical (i.e., contact mechanical) analysis which has been published as KAERI/TR-1113/98. (author). 15 refs., 44 figs., 4 tabs.

  13. A data-mining approach to spacer oligonucleotide typing of Mycobacterium tuberculosis.

    Science.gov (United States)

    Sebban, M; Mokrousov, I; Rastogi, N; Sola, C

    2002-02-01

    The Direct Repeat (DR) locus of Mycobacterium tuberculosis is a suitable model to study (i) molecular epidemiology and (ii) the evolutionary genetics of tuberculosis. This is achieved by a DNA analysis technique (genotyping), called sp acer oligo nucleotide typing (spoligotyping ). In this paper, we investigated data analysis methods to discover intelligible knowledge rules from spoligotyping, that has not yet been applied on such representation. This processing was achieved by applying the C4.5 induction algorithm and knowledge rules were produced. Finally, a Prototype Selection (PS) procedure was applied to eliminate noisy data. This both simplified decision rules, as well as the number of spacers to be tested to solve classification tasks. In the second part of this paper, the contribution of 25 new additional spacers and the knowledge rules inferred were studied from a machine learning point of view. From a statistical point of view, the correlations between spacers were analyzed and suggested that both negative and positive ones may be related to potential structural constraints within the DR locus that may shape its evolution directly or indirectly. By generating knowledge rules induced from decision trees, it was shown that not only the expert knowledge may be modeled but also improved and simplified to solve automatic classification tasks on unknown patterns. A practical consequence of this study may be a simplification of the spoligotyping technique, resulting in a reduction of the experimental constraints and an increase in the number of samples processed.

  14. Insufficient sensitivity of joint aspiration during the two-stage exchange of the hip with spacers.

    Science.gov (United States)

    Boelch, Sebastian Philipp; Weissenberger, Manuel; Spohn, Frederik; Rudert, Maximilian; Luedemann, Martin

    2018-01-10

    Evaluation of infection persistence during the two-stage exchange of the hip is challenging. Joint aspiration before reconstruction is supposed to rule out infection persistence. Sensitivity and specificity of synovial fluid culture and synovial leucocyte count for detecting infection persistence during the two-stage exchange of the hip were evaluated. Ninety-two aspirations before planned joint reconstruction during the two-stage exchange with spacers of the hip were retrospectively analyzed. The sensitivity and specificity of synovial fluid culture was 4.6 and 94.3%. The sensitivity and specificity of synovial leucocyte count at a cut-off value of 2000 cells/μl was 25.0 and 96.9%. C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) values were significantly higher before prosthesis removal and reconstruction or spacer exchange (p = 0.00; p = 0.013 and p = 0.039; p = 0.002) in the infection persistence group. Receiver operating characteristic area under the curve values before prosthesis removal and reconstruction or spacer exchange for ESR were lower (0.516 and 0.635) than for CRP (0.720 and 0.671). Synovial fluid culture and leucocyte count cannot rule out infection persistence during the two-stage exchange of the hip.

  15. Sub-22 nm silicon template nanofabrication by advanced spacer patterning technique for NIL applications

    Science.gov (United States)

    Park, Jong-Moon; Park, Kun-Sik; Kim, Dong-Pyo; Yoo, Seong-Ook; Lee, Jin-Ho

    2013-03-01

    A spacer patterning technique using a poly-Si micro-feature and a SiO2 spacer has been demonstrated to achieve sub-22 nm structures with conventional semiconductor equipments. The sub-22 nm structures have been fabricated by a plasma etching of Si substrate with a spacer oxide mask of which dimension is accurately controlled by the deposited film thickness. The profile of the Si nano-feature was influenced by an O2 flow rate during Si etching in inductively coupled plasma (ICP). As the O2 flow rate was decreased, the etch profile was improved vertically even though the etch rate of Si was slightly decreased. We obtained a 6-inch Si template with both nano- and micro-features of positive shape used for a master mold in nanoimprint lithography (NIL). The nano-sized Si features showed 22-nm width and 145-nm height with the slope of 87°. Further size reduction by anisotropic wet etching with KOH solution was also investigated.

  16. Unsteadiness and transition to turbulence in woven spacer filled channels for Membrane Distillation

    Science.gov (United States)

    Ciofalo, M.; Ponzio, F.; Tamburini, A.; Cipollina, A.; Micale, G.

    2017-01-01

    To characterize the performance of Membrane Distillation (MD) modules, channels filled with woven spacers were investigated by Computational Fluid Dynamics (including Direct Numerical Simulations and the use of the SST k-ω turbulence model) and by parallel experiments with Thermochromic Liquid Crystals. The cases considered here regard mutually orthogonal filaments with a spacer pitch to channel height ratio P/H=2, two spacer orientations θ with respect to the main flow (0° and 45°), and bulk Reynolds numbers Re from ∼200 to ∼2000, an interval of great interest in practical MD applications. For both values of θ, CFD predicted steady-state flow for Re up to ∼300, and chaotic flow for Re larger than ∼400. In the intermediate range Re≈300-400, periodic flow regimes were predicted for both orientations. These regimes were of particular interest and complexity, as they exhibited a slow global oscillation of the flow superimposed on high order harmonics corresponding to fast local oscillations. Experiments confirmed the appearance of unsteadiness for Re>∼300. Heat transfer and friction were little affected by unsteadiness and exhibited a smooth behaviour with Re. The agreement with the experimental results was good using DNS, and acceptable using RANS.

  17. Interaction between zircaloy tube and inconel spacer grid at high temperature

    International Nuclear Information System (INIS)

    Nagase, Fumihisa; Otomo, Takashi; Uetsuka, Hiroshi; Furuta, Teruo

    1990-09-01

    In order to investigate the interaction between fuel cladding and spacer grid of the pressurized water reactor during a severe accident, isothermal reaction tests were performed at the temperature range from 1248 to 1673K. A specimen consisted of a short Zircaloy-4 cladding tube and a piece of spacer grid of Inconel-718. In the tests in an argon atmosphere, eutectic reaction between Zircaloy and Inconel was observed at the contact points at 1248K. Rapid reaction was observed at higher test temperatures. For example, in the test at 1373K for 300s, Zircaloy reacted with Inconel over the entire thickness (0.62mm) of the tube in the vicinity of the contact point. In the present tests, Zircaloy which has higher melting point than Inconel was dissolved preferentially due to eutectic formation. In the tests in an oxygen atmosphere, no eutectic reaction was observed at temperatures below 1437K. A trace of interaction was found at the contact point of specimen heated at 1573 and 1623K. However, decrease in Zircaloy thickness was not measured. The possibility of eutectic reaction between Zircaloy cladding and Inconel spacer grid seems to be quite limited when sufficient oxygen is supplied. (author)

  18. Mobile Commerce

    Directory of Open Access Journals (Sweden)

    Maria Cristina Enache

    2016-07-01

    Full Text Available Mobile commerce, or m-commerce, refers to the use of wireless digital devices to enable transactions on the Web. Described more fully in Chapter 3, m-commerce involves the use of wireless networks to connect cell phones, handheld devices such Blackberries, and personal computers to the Web. Once connected, mobile consumers can conduct transactions, including stock trades, in-store price comparisons, banking, travel reservations, and more.

  19. Effect of electrostatic charge in plastic spacers on the lung delivery of HFA-salbutamol in children

    DEFF Research Database (Denmark)

    Anhøj, J; Bisgaard, H; Lipworth, B J

    1999-01-01

    was delivered on 3 different study days from plastic spacers with mouthpiece. Pre-treatment of the spacers differed between study days: (a) Non-electrostatic 350 ml Babyhaler (coated with benzalkonium chloride) (b) New 350 ml Babyhaler (rinsed in water), and (c) New 145 ml AeroChamber (rinsed in water). Plasma......AIMS: The effect of the electrostatic charge in plastic spacers in vivo on drug delivery to the lung of hydrofluoroalkane (HFA) salbutamol spray was studied in children. METHODS: Five children, aged 7-12 years, were included in a 3-way crossover randomised single-blind trial. Salbutamol HFA spray...... delivered a significantly (Pplastic spacers reduces lung dose in children by more than two-fold. This is clinically significant and the use of potentially electrostatically charged...

  20. INFLUENCE OF THE SIZE OF METHYLENE SPACERS ON THE THERMAL BEHAVIOR OF SEVERAL ALIPHATIC-AROMATIC POLYESTERS

    Directory of Open Access Journals (Sweden)

    NATALIA HURDUC

    2014-04-01

    Full Text Available Polyesters have a wide range of technical applications and therefore their processing is of the utmost importance. Since polyesters are usually processed by melting, their thermal stability is an extremely important characteristic for the exact determination of the operational parameters. The thermal analysis was carried out using a MOM-Budapest derivatograph at the 10 C/min heating speed, aluminum oxide the reference material, and the air conditions were static. The study lead to conclusions on the thermal stability and degradation mechanism depending on the number of methylene groups in the spacer. Thermal stability is supported by the increase in the number of methylene groups in the spacer. The degradation mechanism is complex through successive reactions. The spacer size influences the nature of the micromolecules formed by spacer fragmenting and by the number of carbon atoms, respectively.

  1. Review and Comparison of simulation software for additive manufacturing process: the practical case of dipole End-Spacers

    CERN Document Server

    Vevers, Arturs

    2017-01-01

    Project was made to compare and benchmark simulation software for additive manufacturing. Simulations for End-spacers and HOM crab cavity were made to compare simulation results with 3D scanned data for these parts.

  2. Spacer Thickness-Dependent Electron Transport Performance of Titanium Dioxide Thick Film for Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Reda E. El-Shater

    2015-01-01

    Full Text Available A titanium dioxide (P25 film was deposited by cast coating as conductive photoelectrode and subsequently immersed in dye solution (N719 to fabricate the photoanode of dye-sensitized solar cells (DSSCs. A plastic spacer was used as a separation and sealant layer between the photoanode and the counter electrode. The effect of the thickness of this spacer on the transfer of electrons in the liquid electrolyte of the DSSCs was studied by means of both IV curves and electrochemical impedance. Using a spacer thickness range of 20 μm to 50 μm, efficiency ranges from 3.73% to 7.22%. The highest efficiency of 7.22% was obtained with an optimal spacer thickness of 40 μm.

  3. Low-velocity impact behavior of weft-knitted spacer fabrics reinforced composites based on energy absorption

    Science.gov (United States)

    Hasanalizadeh, F.; Dabiryan, H.; Sadighi, M.

    2017-10-01

    Spacer fabrics are prefered to other types of textile fabrics in energy absorption applications due to existence of pile yarns. The particular geometry of spacer fabrics induce to increase resisting out of plane forces such as impact along their thickness. In order to investigate the low-velocity impact behaviour of composites reinforced with spacer fabric, weft-knitted spacer fabrics with different types of pile orientation and pile length were produced using E-glass yarns. Using produced fabrics and epoxy resin, composites samples were provided by hand lay-up method. Low-velocity impact test was carried out on the prepared samples based on a drop-weight method using spherical steel projectile. The indentation at maximum force was extracted as - comparative criteria used to calculate absorbed energy.The results show that the energy absorption of composites increases by increasing the pile density and pile length.

  4. Review of the correlation developments and a new concept based on mixing mechanism for heat transfer enhancement of spacer grids

    Energy Technology Data Exchange (ETDEWEB)

    Mao, H.; Yang, B.W.; Liu, X. [Xi' an Jiaotong Univ., Shaanxi (China). Science and Technology Center for Advanced Nuclear Fuel Research

    2016-07-15

    Spacer grids could cause heat transfer enhancement both at the spacer grid regions and downstream of the spacer grids as a result of mixing promoted by the spacer grids in the rod bundle. This phenomenon has been demonstrated by many experiments, and several correlations have been developed based on these experimental data. This paper gives a review of the grid-enhanced heat transfer correlation developments in single phase flow. Following the exploration of the correlation development history, a predictive formulation of grid-enhanced heat transfer in single phase flow is established taking into account the effect of both swirl flow and crossflow. With emphasis on modeling of the mixing mechanism associated with the mixing vane grid, the new correlation could better reflect the physical process of the heat transfer augmentation, while a large number of experimental data are needed to determine the coefficients of the new correlation.

  5. Effect of electrostatic charge in plastic spacers on the lung delivery of HFA-salbutamol in children

    DEFF Research Database (Denmark)

    Anhøj, J; Bisgaard, H; Lipworth, B J

    1999-01-01

    AIMS: The effect of the electrostatic charge in plastic spacers in vivo on drug delivery to the lung of hydrofluoroalkane (HFA) salbutamol spray was studied in children. METHODS: Five children, aged 7-12 years, were included in a 3-way crossover randomised single-blind trial. Salbutamol HFA spray...... delivered a significantly (Pcharge in plastic spacers reduces lung dose in children by more than two-fold. This is clinically significant and the use of potentially electrostatically charged...

  6. Distribution of CRISPR spacer matches in viruses and plasmids of crenarchaeal acidothermophiles and implications for their inhibitory mechanism

    DEFF Research Database (Denmark)

    Shah, Shiraz Ali; Hansen, Niels R; Garrett, Roger A

    2009-01-01

    Transcripts from spacer sequences within chromosomal repeat clusters [CRISPRs (clusters of regularly interspaced palindromic repeats)] from archaea have been implicated in inhibiting or regulating the propagation of archaeal viruses and plasmids. For the crenarchaeal thermoacidophiles, the chromo......Transcripts from spacer sequences within chromosomal repeat clusters [CRISPRs (clusters of regularly interspaced palindromic repeats)] from archaea have been implicated in inhibiting or regulating the propagation of archaeal viruses and plasmids. For the crenarchaeal thermoacidophiles...

  7. MO-AB-BRA-02: Modeling Nanoparticle-Eluting Spacer Degradation During Brachytherapy Application with in Situ Dose-Painting

    Energy Technology Data Exchange (ETDEWEB)

    Boateng, F [University of Massachusetts Lowell, Lowell, Massachusetts (United States); Ngwa, W [University of Massachusetts Lowell, Lowell, Massachusetts (United States); Harvard Medical School, Boston, MA (United States)

    2016-06-15

    Purpose: Brachytherapy application with in situ dose-painting using gold nanoparticles (GNP) released from GNP-loaded brachytherapy spacers has been proposed as an innovative approach to increase therapeutic efficacy during brachytherapy. This work investigates the dosimetric impact of slow versus burst release of GNP from next generation biodegradable spacers. Methods: Mathematical models were developed based on experimental data to study the release of GNP from a spacer designed with FDA approved poly(lactic-co-glycolic acid) (PLGA) polymer. The diffusion controlled released process and PLGA polymer degradation kinetics was incorporated in the calculations for the first time. An in vivo determined diffusion coefficient was used for determining the concentration profiles and corresponding dose enhancement based on initial GNP-loading concentrations of 7 mg/g. Results: The results showed that there is significant delay before the concentration profile of GNP diffusion in the tumor is similar to that when burst release is assumed as in previous studies. For example, in the case of burst release after spacer administration, it took up to 25 days for all the GNP to be released from the spacer using diffusion controlled release process only. However, it took up to 45 days when a combined model for both diffusion and polymer degradation processes was used. Based on the tumor concentration profiles, a significant dose enhancement factor (DEF >20%), could be attained at a tumor distances of 5 mm from a spacer loaded with 10 nm GNP sizes. Conclusion: The results highlight the need to take the slow release of GNP from spacers and factors such as biodegradation of polymers into account in research development of GNP-eluting spacers for brachytherapy applications with in-situ dose-painting using gold nanoparticles. The findings suggest that I-125 may be the more appropriate for such applications given the relatively longer half-live compared to other radioisotopes like Pd-103

  8. PEG spacers of different length influence the biological profile of bombesin-based radiolabeled antagonists

    International Nuclear Information System (INIS)

    Jamous, Mazen; Tamma, Maria L.; Gourni, Eleni; Waser, Beatrice; Reubi, Jean C.; Maecke, Helmut R.; Mansi, Rosalba

    2014-01-01

    Introduction: The gastrin-releasing peptide receptor (GRPR) was shown to be expressed with high density on several types of cancers. Radiolabeled peptides for imaging and targeted radionuclide therapy have been developed. In this study, we evaluated the potential of statine-based bombesin antagonists, conjugated to 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) through oligoethyleneglycol spacers, labeled with 177 Lu and we determined the effect of polyethyleneglycol (PEG) spacer length on in vitro and in vivo properties. Methods: The bombesin antagonists were synthesized on solid phase using Fmoc chemistry; the spacers Fmoc-dPEG x -OH (x = 2, 4, 6 and 12) and the DOTA(tBu) 3 were coupled using a standard procedure. The peptides were labeled with 177 Lu and evaluated in vitro (lipophilicity, serum stability, internalization and binding affinity assays). Biodistribution studies were performed in PC-3 tumor-bearing nude mice. Results: The solid-phase synthesis was straightforward with an overall yield ranging from 30% to 35% based on the first Fmoc cleavage. The hydrophilicity increased with spacer length (logD: − 1.95 vs − 2.22 of PEG 2 and PEG 12 analogs, respectively). There is a tendency of increased serum stability by increasing the spacer length (T 1/2 = 246 ± 4 and 584 ± 20 for PEG 2 and PEG 6 analogs, respectively) which seems to reverse with the PEG 12 analog. The IC 50 values are similar with the only significant difference of the PEG 12 analog. The 177 Lu-labeled PEG 4 and PEG 6 conjugates showed similar pharmacokinetic with high tumor uptake and excellent tumor-to-kidney ratios (7.8 and 9.7 at 4 h for the PEG 4 and PEG 6 derivatives, respectively). The pancreas uptake was relatively high at 1 h but it shows fast washout (0.46% ± 0.02% IA/g and 0.29% ± 0.08% IA/g already at 4 h). Conclusion: Among all the studied analogs the PEG 4 and PEG 6 showed significantly better properties. The very high tumor-to-non-target organ ratios, in

  9. Dansyl-naphthalimide dyads as molecular probes: effect of spacer group on metal ion binding properties.

    Science.gov (United States)

    Shankar, Balaraman H; Ramaiah, Danaboyina

    2011-11-17

    Interaction of a few dansyl-naphthalimide conjugates 1a-e linked through polymethylene spacer groups with various metal ions was investigated through absorption, fluorescence, NMR, isothermal calorimetric (ITC), and laser flash photolysis techniques. The characteristic feature of these dyads is that they exhibit competing singlet-singlet energy transfer (SSET) and photoinduced electron transfer (PET) processes, both of which decrease with the increase in spacer length. Depending on the spacer group, these dyads interact selectively with divalent Cu(2+) and Zn(2+) ions, as compared to other mono- and divalent metal ions. Jobs plot analysis showed that these dyads form 2:3 complexes with Cu(2+) ions, while 1:1 complexes were observed with Zn(2+) ions. The association constants for the Zn(2+) and Cu(2+) complexes were determined and are found to be in the order 10(3)-10(5) M(-1). Irrespective of the length of the spacer group, these dyads interestingly act as fluorescence ratiometric molecular probes for Cu(2+) ions by altering the emission intensity of both dansyl and naphthalimide chromophores. In contrast, only the fluorescence intensity of the naphthalimide chromophore of the lower homologues (n = 1-3) was altered by Zn(2+) ions. (1)H NMR and ITC measurements confirmed the involvement of both sulfonamide and dimethylamine groups in the complexation with Cu(2+) ions, while only the latter group was involved with Zn(2+) ions. Laser excitation of the dyads 1a-e showed formation of a transient absorption which can be attributed to the radical cation of the naphthalimide chromophore, whereas only the triplet excited state of the dyads 1a-e was observed in the presence of Cu(2+) ions. Uniquely, the complexation of 1a-e with Cu(2+) ions affects both PET and SSET processes, while only the PET process was partially inhibited by Zn(2+) ions in the lower homologues (n = 1-3) and the higher homologues exhibited negligible changes in their emission properties. Our results

  10. A Comparison of Flow Field Characteristics from PIV Experiment Measurement to Numerical Simulation behind a Spacer in a Vertical Pipe

    Directory of Open Access Journals (Sweden)

    Lávička D.

    2010-07-01

    Full Text Available This paper describes the topic of measurement using a modern laser method (PIV in an annular channel of very small dimensions. The annular channel simulates the flow area around a model of a fuel rod in the VVER nuclear reactor. The annular channel holds spacers which create obstacles to fluid flow. The spacers serve a number of important purposes. In the real nuclear reactor, the spacer holds a fuel rod in the fuel rod bundle. Another important function of the spacer is to influence the flow field characteristics, especially turbulence size, by the shape of the spacer. The value of the turbulence regulates the intensity of heat transfer between the fuel rod and the fluid. Therefore, it is very important to provide a correct description and analysis of the flow field behind the obstacle the spacer generates. The paper further looks into the solution of the same task using numerical simulation. The solution of this task consisted of setting the suitable boundary conditions and of setting the turbulence model for the numerical simulation. The result is a comparison of the flow field characteristics from the experimental measurement and the findings of the numerical simulation. The numerical simulation was carried out using commercial CFD software package, FLUENT.

  11. A Rationale for Going Back to the Future: Use of Disposable Spacers for Pressurised Metered Dose Inhalers

    Directory of Open Access Journals (Sweden)

    Mark Sanders

    2015-01-01

    Full Text Available The introduction of pressurised metered dose inhalers (MDIs in the mid-1950s completely transformed respiratory treatment. Despite decades of availability and healthcare support and development of teaching aids and devices to promote better use, poor pMDI user technique remains a persistent issue. The main pMDI user aid is the spacer/valved holding chamber (VHC device. Spacer/chamber features (size, shape, configuration, construction material, and hygiene considerations can vie with clinical effectiveness (to deliver the same dose as a correctly used pMDI, user convenience, cost, and accessibility. Unsurprisingly, improvised, low-cost alternatives (plastic drink bottles, paper cups, and paper towel rolls have been pressed into seemingly effective service. A UK law change permitting schools to hold emergency inhalers and spacers has prompted a development project to design a low-cost, user-friendly, disposable, and recyclable spacer. This paper spacer requires neither preuse priming nor washing, and has demonstrated reproducible lung delivery of salbutamol sulphate pMDI, comparable to an industry-standard VHC, an alternative paperboard VHC, and pMDI alone. This new device appears to perform better than these other VHC devices at the low flow rates thought achievable by paediatric patients. The data suggest that this disposable spacer may have a place in the single-use emergency setting.

  12. Downflow dryout in a heated ribbed vertical annulus with a cosine power profile (Results from test series ECS-2, WSR, and ECS-2cE)

    Energy Technology Data Exchange (ETDEWEB)

    Larson, T.K.; Anderson, J.L.; Condie, K.G.

    1990-12-01

    Experiments designed to investigate surface dryout in a heated, ribbed annulus test section simulating one of the annular coolant channels of a Savannah River Plant production reactor Mark 22 fuel assembly have been conducted at the Idaho National Engineering Laboratory. The inner surface of the annulus was constructed of aluminum and was electrically heated to provide an axial cosine power profile and a flat azimuthal power shape. Data presented in this report are from the ECS-2, WSR, and ECS-2cE series of tests. These experiments were conducted to examine the onset of wall thermal excursion for a range of flow, inlet fluid temperature, and annulus outlet pressure. Hydraulic boundary conditions on the test section represent flowrates (0.1--1.4 1/s), inlet fluid temperatures (293--345 K), and outlet pressures (-18--139.7 cm of water relative to the bottom of the heated length (61--200 cm of water relative to the bottom of the lower plenum)) expected to occur during the Emergency Coolant System (ECS) phase of postulated Loss-of-Coolant Accident in a production reactor. The onset of thermal excursion based on the present data is consistent with data gathered in test rigs with flat axial power profiles. The data indicate that wall dryout is primarily a function of liquid superficial velocity. Air entrainment rate was observed to be a strong function of the boundary conditions (primarily flowrate and liquid temperature), but had a minor effect on the power at the onset of thermal excursion for the range of conditions examined. 14 refs., 33 figs., 13 tabs.

  13. CT-angiography-based evaluation of the aortic annulus for prosthesis sizing in transcatheter aortic valve implantation (TAVI)-predictive value and optimal thresholds for major anatomic parameters.

    Science.gov (United States)

    Schwarz, Florian; Lange, Philipp; Zinsser, Dominik; Greif, Martin; Boekstegers, Peter; Schmitz, Christoph; Reiser, Maximilian F; Kupatt, Christian; Becker, Hans C

    2014-01-01

    To evaluate the predictive value of CT-derived measurements of the aortic annulus for prosthesis sizing in transcatheter aortic valve implantation (TAVI) and to calculate optimal cutoff values for the selection of various prosthesis sizes. The local IRB waived approval for this single-center retrospective analysis. Of 441 consecutive TAVI-patients, 90 were excluded (death within 30 days: 13; more than mild aortic regurgitation: 10; other reasons: 67). In the remaining 351 patients, the CoreValve (Medtronic) and the Edwards Sapien XT valve (Edwards Lifesciences) were implanted in 235 and 116 patients. Optimal prosthesis size was determined during TAVI by inflation of a balloon catheter at the aortic annulus. All patients had undergone CT-angiography of the heart or body trunk prior to TAVI. Using these datasets, the diameter of the long and short axis as well as the circumference and the area of the aortic annulus were measured. Multi-Class Receiver-Operator-Curve analyses were used to determine the predictive value of all variables and to define optimal cutoff-values. Differences between patients who underwent implantation of the small, medium or large prosthesis were significant for all except the large vs. medium CoreValve (all p'sprosthesis size for both manufacturers (multi-class AUC's: 0.80, 0.88, 0.91, 0.88, 0.88, 0.89). Using the calculated optimal cutoff-values, prosthesis size is predicted correctly in 85% of cases. CT-based aortic root measurements permit excellent prediction of the prosthesis size considered optimal during TAVI.

  14. Effects of a 3D segmental prosthetic system for tricuspid valve annulus remodelling on the right coronary artery: a human cadaveric coronary angiography study.

    Science.gov (United States)

    Riki-Marishani, Mohsen; Gholoobi, Arash; Sazegar, Ghasem; Aazami, Mathias H; Hedjazi, Aria; Sajjadian, Maryam; Ebrahimi, Mahmoud; Aghaii-Zade Torabi, Ahmad

    2017-09-01

    A prosthetic system to repair secondary tricuspid valve regurgitation was developed. The conceptual engineering of the current device is based on 3D segmental remodelling of the tricuspid valve annulus in lieu of reductive annuloplasty. This study was designed to investigate the operational safety of the current prosthetic system with regard to the anatomical integrity of the right coronary artery (RCA) in fresh cadaveric human hearts. During the study period, from January to April 2016, the current prosthetic system was implanted on the tricuspid valve annulus in fresh cadaveric human hearts that met the study's inclusion criteria. The prepared specimens were investigated via selective coronary angiography of the RCA in the catheterization laboratory. The RCA angiographic anatomies were categorized as normal, distorted, kinked or occluded. Sixteen specimens underwent implantation of the current prosthetic system. The mean age of the cadaveric human hearts was 43.24 ± 15.79 years, with vehicle accident being the primary cause of death (59%). A dominant RCA was noticed in 62.5% of the specimens. None of the specimens displayed any injury, distortion, kinking or occlusion in the RCA due to the implantation of the prostheses. In light of the results of the present study, undertaken on fresh cadaveric human heart specimens, the current segmental prosthetic system for 3D remodelling of the tricuspid valve annulus seems to be safe vis-à-vis the anatomical integrity of the RCA. Further in vivo studies are needed to investigate the functional features of the current prosthetic system with a view to addressing the complex pathophysiology of secondary tricuspid valve regurgitation. © The Author 2017. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

  15. Automated 3D analysis of pre-procedural MDCT to predict annulus plane angulation and C-arm positioning: benefit on procedural outcome in patients referred for TAVR.

    Science.gov (United States)

    Samim, Mariam; Stella, Pieter R; Agostoni, Pierfrancesco; Kluin, Jolanda; Ramjankhan, Faiez; Budde, Ricardo P J; Sieswerda, Gertjan; Algeri, Emanuela; van Belle, Camille; Elkalioubie, Ahmed; Juthier, Francis; Belkacemi, Anouar; Bertrand, Michel E; Doevendans, Pieter A; Van Belle, Eric

    2013-02-01

    The aim of this study was to determine whether pre-procedural analysis of multidetector row computed tomography (MDCT) scans could accurately predict the "line of perpendicularity" (LP) of the aortic annulus and corresponding C-arm angulations required for prosthesis delivery and impact the outcome of the procedure. Optimal positioning of the transcatheter aortic prosthesis is paramount to transcatheter aortic valve replacement (TAVR) procedural success. All patients referred for TAVR at our center underwent a routine pre-procedural MDCT scan. A 3-dimensional (3D) analysis using software dedicated to define the LP of the aortic annulus and the corresponding C-arm positioning was performed in 71 consecutive patients. In 35 patients, the results of the MDCT analysis were not available at the time of the procedure (angiography cohort). In that cohort the position of the C-arm was determined during the procedure using ad-hoc angiography. In 36 patients, the MDCT analysis was performed pre-procedure and results were available at the time of the procedure (MDCT cohort). In that cohort the position of the C-arm was derived from the MDCT analysis rather than by ad-hoc angiography. Intraobserver and interobserver reproducibility of MDCT analysis to predict the LP of the aortic annulus were excellent (kappa = 1 and 0.94, respectively). Patient variations of the LP ranged >70°. Compared with the angiography cohort, the MDCT cohort was associated with a significant decrease in implantation time (p = 0.0001), radiation exposure (p = 0.02), amount of contrast (p = 0.001), and risk of acute kidney injury (p = 0.03). Additionally, the combined rate of valve malposition and aortic regurgitation was also reduced (6% vs. 23%, p = 0.03). Automated 3D analysis of pre-implantation MDCT accurately predicts the LP of the aortic annulus and the corresponding C-arm position required for TAVR. With this approach, the implantation of the balloon-expandable prosthetic valve can be performed

  16. Formation of lamellar cross bridges in the annulus fibrosus of the intervertebral disc is a consequence of vascular regression.

    Science.gov (United States)

    Smith, Lachlan J; Elliott, Dawn M

    2011-05-01

    Cross bridges are radial structures within the highly organized lamellar structure of the annulus fibrosus of the intervertebral disc that connect two or more non-consecutive lamellae. Their origin and function are unknown. During fetal development, blood vessels penetrate deep within the AF and recede during postnatal growth. We hypothesized that cross bridges are the pathways left by these receding blood vessels. Initially, the presence of cross bridges was confirmed in cadaveric human discs aged 25 and 53 years. Next, L1-L2 intervertebral discs (n=4) from sheep ranging in age from 75 days fetal gestation to adult were processed for paraffin histology. Mid-sagittal sections were immunostained for endothelial cell marker PECAM-1. The anterior and posterior AF were imaged using differential interference contrast microscopy, and the following parameters were quantified: total number of distinct lamellae, total number of cross bridges, percentage of cross bridges staining positive for PECAM-1, cross bridge penetration depth (% total lamellae), and PECAM-1 positive cross bridge penetration depth. Cross bridges were first observed at 100 days fetal gestation. The overall number peaked in neonates then remained relatively unchanged. The percentage of PECAM-1 positive cross bridges declined progressively from almost 100% at 100 days gestation to less than 10% in adults. Cross bridge penetration depth peaked in neonates then remained unchanged at subsequent ages. Depth of PECAM-1 positive cross bridges decreased progressively after birth. Findings were similar for both the anterior and posterior. The AF lamellar architecture is established early in development. It later becomes disrupted as a consequence of vascularization. Blood vessels then recede, perhaps due to increasing mechanical stresses in the surrounding matrix. In this study we present evidence that the pathways left by receding blood vessels remain as lamellar cross bridges. It is unclear whether the presence

  17. [Comparison of results between fenestration discectomy associated with annulus repair and fenestration discectomy for lumbar disc herniation in the adolescents].

    Science.gov (United States)

    Li, J; Ma, C; Li, Y M; Wang, Z H; Zhao, M; Feng, J; Dai, W X

    2016-08-23

    To compare the preliminary clinical outcomes of fenestration discectomy associated with annulus repair (FDAR) and fenestration discectomy (FD) for lumbar disc herniation in the adolescents. The data of 26 adolescent patients with single segment lumbar disc herniation who were admitted to the Department of Orthopedics, Xuzhou Central Hospital from October 2012 to October 2014 were retrospectively studied. All patients were divided into 2 groups, including 12 patients undergoing FDAR and 14 patients undergoing FD respectively. The factors including the length of skin incision, amount of intraoperative bleeding, operation time and duration of hospitalization were compared. The indentation of dura were measured from MRI. Pfirrmann grading system was used for assessment of lumbar disc degeneration preoperatively and 1 year later. The visual analogue scale (VAS), the oswestry disability index (ODI) and Japanese Orthopedic Association (JOA) scores were used to measure the clinical outcomes. Simultaneously, surgical complications, and postoperative recurrence of lumbar disc herniation were recorded. There were no significant differences in the observational factors such as the skin incision length, amount of intraoperative bleeding, operation time, and duration of hospitalization between the FDAR and FD groups (P>0.05). The indentation of the dura significantly reduced after surgery in each group [FDAR: (7.3±2.6) vs (1.3±0.8) mm; FD: (7.4±3.1) vs (2.9±0.7) mm; both Pdisc degeneration in FDAR group was the same as that of in FD group. The postoperative VAS scores and ODI scores at each follow-up time point in both groups were significantly improved when compared with the preoperative ones (P0.05). According to the modified MacNab criteria, there were no statistically significant differences between the 2 groups in the excellent and good rate (FDAR: 89.3%, FD: 88.5%; P>0.05). There were no dural tears, disc space infection, hematoma formation in the spinal canal and

  18. Accelerated premature stress-induced senescence of young annulus fibrosus cells of rats by high glucose-induced oxidative stress.

    Science.gov (United States)

    Park, Jong-Soo; Park, Jong-Beom; Park, In-Joo; Park, Eun-Young

    2014-06-01

    Diabetes mellitus (DM) is thought to be an important aetiological factor in intervertebral disc degeneration. A glucose-mediated increase of oxidative stress is a major causative factor in development of diseases associated with DM. The aim of this study was to investigate the effect of high glucose on mitochondrial damage, oxidative stress and senescence of young annulus fibrosus (AF) cells. AF cells were isolated from four-week-old young rats, cultured, and placed in either 10 % FBS (normal control) or 10 % FBS plus two different high glucose concentrations (0.1 M and 0.2 M) (experimental conditions) for one and three days. We identified and quantified the mitochondrial damage and reactive oxygen species (ROS) (oxidative stress). We also identified and quantified the occurrence of senescence and telomerase activity. Finally, the expressions of proteins were determined related to replicative senescence (p53-p21-pRB) and stress-induced senescence (p16-pRB). Two high glucoses enhanced the mitochondrial damage in young rat AF cells, which resulted in an excessive generation of ROS in a dose- and time-dependent manner for one and three days compared to normal control. Two high glucose concentrations increased the occurrence of senescence of young AF cells in a dose- and time-dependent manner. Telomerase activity declined in a dose- and time-dependent manner. Both high glucose treatments increased the expressions of p16 and pRB proteins in young rat AF cells for one and three days. However, compared to normal control, the expressions of p53 and p21 proteins were decreased in young rat AF cells treated with both high glucoses for one and three days. The present study demonstrated that high glucose-induced oxidative stress accelerates premature stress-induced senescence in young rat AF cells in a dose- and time-dependent manner rather than replicative senescence. These results suggest that prevention of excessive generation of oxidative stress by strict blood glucose

  19. Do mechanical strain and TNF-α interact to amplify pro-inflammatory cytokine production in human annulus fibrosus cells?

    Science.gov (United States)

    Likhitpanichkul, Morakot; Torre, Olivia M; Gruen, Jadry; Walter, Benjamin A; Hecht, Andrew C; Iatridis, James C

    2016-05-03

    During intervertebral disc (IVD) injury and degeneration, annulus fibrosus (AF) cells experience large mechanical strains in a pro-inflammatory milieu. We hypothesized that TNF-α, an initiator of IVD inflammation, modifies AF cell mechanobiology via cytoskeletal changes, and interacts with mechanical strain to enhance pro-inflammatory cytokine production. Human AF cells (N=5, Thompson grades 2-4) were stretched uniaxially on collagen-I coated chambers to 0%, 5% (physiological) or 15% (pathologic) strains at 0.5Hz for 24h under hypoxic conditions with or without TNF-α (10ng/mL). AF cells were treated with anti-TNF-α and anti-IL-6. ELISA assessed IL-1β, IL-6, and IL-8 production and immunocytochemistry measured F-actin, vinculin and α-tubulin in AF cells. TNF-α significantly increased AF cell pro-inflammatory cytokine production compared to basal conditions (IL-1β:2.0±1.4-84.0±77.3, IL-6:10.6±9.9-280.9±214.1, IL-8:23.9±26.0-5125.1±4170.8pg/ml for basal and TNF-α treatment, respectively) as expected, but mechanical strain did not. Pathologic strain in combination with TNF-α increased IL-1β, and IL-8 but not IL-6 production of AF cells. TNF-α treatment altered F-actin and α-tubulin in AF cells, suggestive of altered cytoskeletal stiffness. Anti-TNF-α (infliximab) significantly inhibited pro-inflammatory cytokine production while anti-IL-6 (atlizumab) did not. In conclusion, TNF-α altered AF cell mechanobiology with cytoskeletal remodeling that potentially sensitized AF cells to mechanical strain and increased TNF-α-induced pro-inflammatory cytokine production. Results suggest an interaction between TNF-α and mechanical strain and future mechanistic studies are required to validate these observations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Flows in Concentric Annulus

    Directory of Open Access Journals (Sweden)

    Shuichi Torii

    1998-01-01

    stress turbulence model is employed to determine three normal components of the Reynolds stress and its off-diagonal one. The turbulent heat flux is expressed by Boussinesq approximation in which the eddy diffusivity.for heat is given as functions of the temperature variance t2¯ and the dissipation rate of temperate fluctuations εt. The governing boundarylayer equations are discretized by means of a control volume finite-difference technique and numerically solved using the marching procedure. An inner core rotation causes an amplification of the three normal components of the Reynolds stress over the whole cross section, resulting in a substantial enhancement in the Nusselt number.

  1. Mobile Marketing

    OpenAIRE

    竹安, 数博; Takeyasu, Kazuhiro

    2005-01-01

    This article deals with one of the modern trends in marketing communication, which is mobile marketing. Towards the end of 2008, several projects which use mobile phones for target marketing communication were launched. Commercial SMS´s are sent on the base of agreement or registration of the consumers on special websites, for example hellomobil.cz. The benefit for the consumers is the bonus which can have more forms - not only sending money to the account, free SMS´s/MMS´s and minutes but al...

  2. Urban Mobility

    DEFF Research Database (Denmark)

    2017-01-01

    This anthology is the proceedings publication from the 2015 NAF Symposium in Malmö, Sweden. The aim of the 2015 NAF Symposium “Urban Mobility – Architectures, Geographies and Social Space” was to facilitate a cross-disciplinary discussion on urban mobility in which the juxtaposition of different...... the symposium collects six articles written by authors who all presented papers at the event. Contributing authors: Ditte Bendix Lanng, Ole B. Jensen, David Pinder, Magnus Rönn, Jani Tartia, Anne Tietjen, Anne Elisabeth Toft, Even Smith Wergeland, Simon Wind...

  3. Sustainable Mobility

    DEFF Research Database (Denmark)

    Kjærulff, Aslak Aamot

    This paper combines strands of mobilities theory and planning theory, and develops a qualitative approach to look across emerging planning practices. By actively following 8 Danish urban and transport planners, over the course of 2 years, we learn how their practices have changed, inspired...

  4. Mobile IP

    NARCIS (Netherlands)

    Heijenk, Geert; Sallent, S.; Pras, Aiko

    1999-01-01

    The Internet is growing exponentially, both in the amount of traffic carried, and in the amount of hosts connected. IP technology is becoming more and more important, in company networks (Intranets), and also in the core networks for the next generation mobile networks. Further, wireless access to

  5. The CRISPRdb database and tools to display CRISPRs and to generate dictionaries of spacers and repeats

    Directory of Open Access Journals (Sweden)

    Vergnaud Gilles

    2007-05-01

    Full Text Available Abstract Background In Archeae and Bacteria, the repeated elements called CRISPRs for "clustered regularly interspaced short palindromic repeats" are believed to participate in the defence against viruses. Short sequences called spacers are stored in-between repeated elements. In the current model, motifs comprising spacers and repeats may target an invading DNA and lead to its degradation through a proposed mechanism similar to RNA interference. Analysis of intra-species polymorphism shows that new motifs (one spacer and one repeated element are added in a polarised fashion. Although their principal characteristics have been described, a lot remains to be discovered on the way CRISPRs are created and evolve. As new genome sequences become available it appears necessary to develop automated scanning tools to make available CRISPRs related information and to facilitate additional investigations. Description We have produced a program, CRISPRFinder, which identifies CRISPRs and extracts the repeated and unique sequences. Using this software, a database is constructed which is automatically updated monthly from newly released genome sequences. Additional tools were created to allow the alignment of flanking sequences in search for similarities between different loci and to build dictionaries of unique sequences. To date, almost six hundred CRISPRs have been identified in 475 published genomes. Two Archeae out of thirty-seven and about half of Bacteria do not possess a CRISPR. Fine analysis of repeated sequences strongly supports the current view that new motifs are added at one end of the CRISPR adjacent to the putative promoter. Conclusion It is hoped that availability of a public database, regularly updated and which can be queried on the web will help in further dissecting and understanding CRISPR structure and flanking sequences evolution. Subsequent analyses of the intra-species CRISPR polymorphism will be facilitated by CRISPRFinder and the

  6. PairWise Neighbours database: overlaps and spacers among prokaryote genomes

    Directory of Open Access Journals (Sweden)

    Garcia-Vallvé Santiago

    2009-06-01

    Full Text Available Abstract Background Although prokaryotes live in a variety of habitats and possess different metabolic and genomic complexity, they have several genomic architectural features in common. The overlapping genes are a common feature of the prokaryote genomes. The overlapping lengths tend to be short because as the overlaps become longer they have more risk of deleterious mutations. The spacers between genes tend to be short too because of the tendency to reduce the non coding DNA among prokaryotes. However they must be long enough to maintain essential regulatory signals such as the Shine-Dalgarno (SD sequence, which is responsible of an efficient translation. Description PairWise Neighbours is an interactive and intuitive database used for retrieving information about the spacers and overlapping genes among bacterial and archaeal genomes. It contains 1,956,294 gene pairs from 678 fully sequenced prokaryote genomes and is freely available at the URL http://genomes.urv.cat/pwneigh. This database provides information about the overlaps and their conservation across species. Furthermore, it allows the wide analysis of the intergenic regions providing useful information such as the location and strength of the SD sequence. Conclusion There are experiments and bioinformatic analysis that rely on correct annotations of the initiation site. Therefore, a database that studies the overlaps and spacers among prokaryotes appears to be desirable. PairWise Neighbours database permits the reliability analysis of the overlapping structures and the study of the SD presence and location among the adjacent genes, which may help to check the annotation of the initiation sites.

  7. Optimization of an organic photovoltaic device via modulation of thickness of photoactive and optical spacer layers.

    Science.gov (United States)

    Li, Qi; Yoon, Won Jung; Ju, Heongkyu

    2014-01-01

    We examine the modulation effects of thicknesses of both a photoactive layer (a bulk-heterojunction (BHJ) of poly(3-hexylthiophene) and [6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM)) and an optical spacer of a transparent metal oxide, for power conversion efficiency optimization of organic photovoltaic devices. The redistribution of the optical intensity at the photoactive layer via the thickness modulation of both layers is taken into account, to produce three-dimensional (3D) plots as a function of both layer thicknesses of 0 to 400 nm range (5 nm step), for the device efficiency optimization. The modulation pattern of absorption is produced in the 3D plot as scanning the thicknesses of both layers as a result of modulation of interference between incoming and reflected light, which can be secured by changing the effective optical path length between two electrodes of a photovoltaic device. It is also seen that the case of inserting the spacer of the higher refractive index demands finer adjustment of the spacer layer thickness to achieve the optimum device efficiency. In addition, the series resistance of the photoactive layer of the thickness range of 0 to 70 nm is taken into account to provide the 3D plots as a function of the scanned thicknesses of both layers. Inclusion of the series resistance of the photoactive layer, which is also the function of its thickness, in the simulation, indicates that the series resistance can influence qualitatively the dependence of power conversion efficiency (PCE) on the thicknesses of both layers. We also find that minimization of series resistance, e.g., by device annealing, allows not only the relevant voltage to increase but also the optimum thickness of the photoactive layer to increase, leading to more absorption of light.

  8. Diversity in a Polymicrobial Community Revealed by Analysis of Viromes, Endolysins and CRISPR Spacers.

    Directory of Open Access Journals (Sweden)

    Michelle Davison

    Full Text Available The polymicrobial biofilm communities in Mushroom and Octopus Spring in Yellowstone National Park (YNP are well characterized, yet little is known about the phage populations. Dominant species, Synechococcus sp. JA-2-3B'a(2-13, Synechococcus sp. JA-3-3Ab, Chloroflexus sp. Y-400-fl, and Roseiflexus sp. RS-1, contain multiple CRISPR-Cas arrays, suggesting complex interactions with phage predators. To analyze phage populations from Octopus Spring biofilms, we sequenced a viral enriched fraction. To assemble and analyze phage metagenomic data, we developed a custom module, VIRITAS, implemented within the MetAMOS framework. This module bins contigs into groups based on tetranucleotide frequencies and CRISPR spacer-protospacer matching and ORF calling. Using this pipeline we were able to assemble phage sequences into contigs and bin them into three clusters that corroborated with their potential host range. The virome contained 52,348 predicted ORFs; some were clearly phage-like; 9319 ORFs had a recognizable Pfam domain while the rest were hypothetical. Of the recognized domains with CRISPR spacer matches, was the phage endolysin used by lytic phage to disrupt cells. Analysis of the endolysins present in the thermophilic cyanophage contigs revealed a subset of characterized endolysins as well as a Glyco_hydro_108 (PF05838 domain not previously associated with sequenced cyanophages. A search for CRISPR spacer matches to all identified phage endolysins demonstrated that a majority of endolysin domains were targets. This strategy provides a general way to link host and phage as endolysins are known to be widely distributed in bacteriophage. Endolysins can also provide information about host cell wall composition and have the additional potential to be used as targets for novel therapeutics.

  9. Fresh Autologous Pericardium to Reconstruct the Pulmonary Valve at the Annulus When Tetralogy of Fallot Requires a Transannular Patch at Midterm.

    Science.gov (United States)

    Pande, Shantanu; Sharma, Jugal K; Siddartha, C R; Bansal, Anubhav; Agarwal, Surendra K; Tewari, Prabhat; Kapoor, Aditya

    2016-06-01

    Tetralogy of Fallot often requires reconstruction of the right ventricular outflow tract with a transannular patch (TAP), but this renders the pulmonary valve incompetent and eventually leads to right ventricular dysfunction. We retrospectively evaluated the efficacy of a reconstructed pulmonary valve and annulus in 70 patients who underwent, from December 2006 through December 2010, complete correction of tetralogy of Fallot. We divided the 70 patients into 2 groups in accordance with whether they required (n=50) or did not require (n=20) a TAP. We used autologous untreated pericardium to fashion the TAP and to create both an annulus of the correct size and a competent pulmonary valve with native leaflets. We evaluated the efficiency of this procedure both functionally and anatomically. The median age of the patients was 11 years (range, 2-38 yr). There were 56 males, with no significant difference in sexual distribution between groups. The clinical follow-up was 88% for 57.5 months, and the echocardiographic follow-up was 80% for 36 months. There was no significant difference in outflow gradient or in the occurrence of pulmonary insufficiency between the TAP group (none, 31; mild, 12; moderate, 6; and severe, 1) and the No-TAP group (none, 16; moderate, 2; and severe, 2) (P=0.59). Nor was there any thickening or calcification in the constructed valves. We conclude that pulmonary valves constructed of untreated autologous pericardium performed as well as native valves after total tetralogy of Fallot correction at midterm.

  10. Modal properties of the flexural vibrating package of rods linked by spacer grids

    Directory of Open Access Journals (Sweden)

    Zeman V.

    2011-06-01

    Full Text Available The paper deals with the modelling and modal analysis of the large package of identical parallel rods linked by transverse springs (spacer grids placed on several level spacings. The rod discretization by finite element method is based on Rayleigh beam theory. For the cyclic and central symmetric package of rods (such as fuel rods in nuclear fuel assembly the system decomposition on the identical revolved rod segments was applied. A modal synthesis method with condensation is used for modelling of the whole system. The presented method is the first step for modelling the nuclear fuel assembly vibration caused by excitation determined by the support plate motion of the reactor core.

  11. Development of a manufacturing process for Zr-based spacer grid materials

    International Nuclear Information System (INIS)

    Jung, Yang-Il; Lee, Myung-Ho; Choi, Byoung-Kwon; Park, Jeong-Yong; Jeong, Yong-Hwan

    2009-01-01

    A novel manufacturing process for zirconium-based alloy strips has been developed. This process consists of a prior heat-treatment under a monotectoid temperature before subsequent deformation processes. During the prior heat-treatment process at 580 deg. C for 10 h, β-Nb phase particles were precipitated. The second phase particles stabilized the alloy from corrosion even the subsequent annealings at high temperatures. This result enhances the manufacturability of zirconium-based alloys, especially for high strength alloys with high Nb contents. The process developed can also be applied to commercial zirconium-based spacer grid materials, which would give rise to a higher producibility of such materials.

  12. Influence of the boundary conditions on heat and mass transfer in spacer-filled channels

    Science.gov (United States)

    Ciofalo, M.; La Cerva, M. F.; Di Liberto, M.; Tamburini, A.

    2017-11-01

    The purpose of this study is to discuss some problems which arise in heat or mass transfer in complex channels, with special reference to the spacer-filled channels adopted in membrane processes. Among the issues addressed are the consistent definition of local and mean heat or mass transfer coefficients; the influence of the wall boundary conditions; the influence of one-side versus two-side heat/mass transfer. Most of the results discussed were obtained by finite volume CFD simulations concerning heat transfer in Membrane Distillation or mass transfer in Electrodialysis and Reverse Electrodialysis, but many of the conclusions apply also to different processes involving geometrically complex channels

  13. Mobile Customer Relationship Management and Mobile Security

    Science.gov (United States)

    Sanayei, Ali; Mirzaei, Abas

    The purpose of this study is twofold. First, in order to guarantee a coherent discussion about mobile customer relationship management (mCRM), this paper presents a conceptualization of mCRM delineating its unique characteristics because of Among the variety of mobile services, considerable attention has been devoted to mobile marketing and in particular to mobile customer relationship management services. Second, the authors discusses the security risks in mobile computing in different level(user, mobile device, wireless network,...) and finally we focus on enterprise mobile security and it's subgroups with a series of suggestion and solution for improve mobile computing security.

  14. Comparative study of the contribution of various PWR spacer grid components to hydrodynamic and wall pressure characteristics

    International Nuclear Information System (INIS)

    Bhattacharjee, Saptarshi; Ricciardi, Guillaume; Viazzo, Stéphane

    2017-01-01

    Highlights: • Complex geometry inside a PWR fuel assembly is simulated using simplified 3D models. • Structured meshes are generated as far as possible. • Fluctuating hydrodynamic and wall pressure field are analyzed using LES. • Comparative studies between square spacer grid, circular spacer grid and mixing vanes are presented. • Simulations are compared with experimental data. - Abstract: Flow-induced vibrations in a pressurized water reactor (PWR) core can cause fretting wear in fuel rods. These vibrations can compromise safety of a nuclear reactor. So, it is necessary to know the random fluctuating forces acting on the rods which cause these vibrations. In this paper, simplified 3D models like square spacer grid, circular spacer grid and symmetric mixing vanes have been used inside an annular pipe. Hydrodynamic and wall pressure characteristics are evaluated using large eddy simulations (LES). Structured meshes are generated as far as possible. Simulations are compared with an experiment. Results show that the grid and vanes have a combined effect: grid accelerates the flow whereas the vanes contribute to the swirl structures. Spectral analysis of the simulations illustrate vortex shedding phenomenon in the wake of spacer grids. This initial study opens up interesting perspectives towards improving the modeling strategy and understanding the complex phenomenon inside a PWR core.

  15. Comparative study of the contribution of various PWR spacer grid components to hydrodynamic and wall pressure characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharjee, Saptarshi, E-mail: saptarshi.bhattacharjee@outlook.com [Alternative Energies and Atomic Energy Commission (CEA) – Cadarache, DEN/DTN/STCP/LHC, 13108 Saint Paul lez Durance Cedex (France); Laboratoire de Mécanique, Modélisation et Procédés Propres (M2P2), UMR7340 CNRS, Aix-Marseille Université, Centrale Marseille, 13451 Marseille Cedex (France); Ricciardi, Guillaume [Alternative Energies and Atomic Energy Commission (CEA) – Cadarache, DEN/DTN/STCP/LHC, 13108 Saint Paul lez Durance Cedex (France); Viazzo, Stéphane [Laboratoire de Mécanique, Modélisation et Procédés Propres (M2P2), UMR7340 CNRS, Aix-Marseille Université, Centrale Marseille, 13451 Marseille Cedex (France)

    2017-06-15

    Highlights: • Complex geometry inside a PWR fuel assembly is simulated using simplified 3D models. • Structured meshes are generated as far as possible. • Fluctuating hydrodynamic and wall pressure field are analyzed using LES. • Comparative studies between square spacer grid, circular spacer grid and mixing vanes are presented. • Simulations are compared with experimental data. - Abstract: Flow-induced vibrations in a pressurized water reactor (PWR) core can cause fretting wear in fuel rods. These vibrations can compromise safety of a nuclear reactor. So, it is necessary to know the random fluctuating forces acting on the rods which cause these vibrations. In this paper, simplified 3D models like square spacer grid, circular spacer grid and symmetric mixing vanes have been used inside an annular pipe. Hydrodynamic and wall pressure characteristics are evaluated using large eddy simulations (LES). Structured meshes are generated as far as possible. Simulations are compared with an experiment. Results show that the grid and vanes have a combined effect: grid accelerates the flow whereas the vanes contribute to the swirl structures. Spectral analysis of the simulations illustrate vortex shedding phenomenon in the wake of spacer grids. This initial study opens up interesting perspectives towards improving the modeling strategy and understanding the complex phenomenon inside a PWR core.

  16. Anti-cas spacers in orphan CRISPR4 arrays prevent uptake of active CRISPR-Cas I-F systems.

    Science.gov (United States)

    Almendros, Cristóbal; Guzmán, Noemí M; García-Martínez, Jesús; Mojica, Francisco J M

    2016-06-06

    Archaea and bacteria harbour clustered regularly interspaced short palindromic repeats (CRISPR) loci. These arrays encode RNA molecules (crRNA), each containing a sequence of a single repeat-intervening spacer. The crRNAs guide CRISPR-associated (Cas) proteins to cleave nucleic acids complementary to the crRNA spacer, thus interfering with targeted foreign elements. Notably, pre-existing spacers may trigger the acquisition of new spacers from the target molecule by means of a primed adaptation mechanism. Here, we show that naturally occurring orphan CRISPR arrays that contain spacers matching sequences of the cognate (absent) cas genes are able to elicit both primed adaptation and direct interference against genetic elements carrying those genes. Our findings show the existence of an anti-cas mechanism that prevents the transfer of a fully equipped CRISPR-Cas system. Hence, they suggest that CRISPR immunity may be undesired by particular prokaryotes, potentially because they could limit possibilities for gaining favourable sequences by lateral transfer.

  17. The Construction of Chimeric T-Cell Receptor with Spacer Base of Modeling Study of VHH and MUC1 Interaction

    Directory of Open Access Journals (Sweden)

    Nazanin Pirooznia

    2011-01-01

    Full Text Available Adaptive cell immunotherapy with the use of chimeric receptors leads to the best and most specific response against tumors. Chimeric receptors consist of a signaling fragment, extracellular spacer, costimulating domain, and an antibody. Antibodies cause immunogenicity; therefore, VHH is a good replacement for ScFv in chimeric receptors. Since peptide sequences have an influence on chimeric receptors, the effect of peptide domains on each other's conformation were investigated. CD3Zeta, CD28, VHH and CD8α, and FcgIIα are used as signaling moieties, costimulating domain, antibody, and spacers, respectively. To investigate the influence of the ligation of spacers on the conformational structure of VHH, models of VHH were constructed. Molecular dynamics simulation was run to study the influence of the presence of spacers on the conformational changes in the binding sites of VHH. Root mean square deviation and root mean square fluctuation of critical segments in the binding site showed no noticeable differences with those in the native VHH. Results from molecular docking revealed that the presence of spacer FcgIIα causes an increasing effect on VHH with MUC1 interaction. Each of the constructs was transformed into the Jurkat E6.1. Expression analysis and evaluation of their functions were examined. The results showed good expression and function.

  18. Sequences in the intergenic spacer influence RNA Pol I transcription from the human rRNA promoter

    Energy Technology Data Exchange (ETDEWEB)

    Li, W.M.; Sylvester, J.E. [Hahnemann Univ., Philadelphia, PA (United States)

    1994-09-01

    In most eucaryotic species, ribosomal genes are tandemly repeated about 100-5000 times per haploid genome. The 43 Kb human rDNA repeat consists of a 13 Kb coding region for the 18S, 5.8S, 28S ribosomal RNAs (rRNAs) and transcribed spacers separated by a 30 Kb intergenic spacer. For species such as frog, mouse and rat, sequences in the intergenic spacer other than the gene promoter have been shown to modulate transcription of the ribosomal gene. These sequences are spacer promoters, enhancers and the terminator for spacer transcription. We are addressing whether the human ribosomal gene promoter is similarly influenced. In-vitro transcription run-off assays have revealed that the 4.5 kb region (CBE), directly upstream of the gene promoter, has cis-stimulation and trans-competition properties. This suggests that the CBE fragment contains an enhancer(s) for ribosomal gene transcription. Further experiments have shown that a fragment ({approximately}1.6 kb) within the CBE fragment also has trans-competition function. Deletion subclones of this region are being tested to delineate the exact sequences responsible for these modulating activities. Previous sequence analysis and functional studies have revealed that CBE contains regions of DNA capable of adopting alternative structures such as bent DNA, Z-DNA, and triple-stranded DNA. Whether these structures are required for modulating transcription remains to be determined as does the specific DNA-protein interaction involved.

  19. Urban Mobility

    DEFF Research Database (Denmark)

    2017-01-01

    This anthology is the proceedings publication from the 2015 NAF Symposium in Malmö, Sweden. The aim of the 2015 NAF Symposium “Urban Mobility – Architectures, Geographies and Social Space” was to facilitate a cross-disciplinary discussion on urban mobility in which the juxtaposition of different...... discursive perceptions of the concept would foster greater insight into and understanding of both the challenges and potentials that it represents. It focused on some of the key themes currently facing cities and the urban: the transformation of the city and our built environment; migration; rural decline......; the interaction between city, architecture, and inhabitants; the role of architects and architecture in the creation of democratic and sustainable urban contexts; the city and its representation; the politics of intervention; and the actions of governing and developing. This proceedings publication from...

  20. The African Mobile Story

    DEFF Research Database (Denmark)

    This book identifies the factors that has enabled the growth of mobile telephony in Africa. The book covers the regulatory factors, the development and usage of mobile application, mobile security and sustainable power source for mobile networks......This book identifies the factors that has enabled the growth of mobile telephony in Africa. The book covers the regulatory factors, the development and usage of mobile application, mobile security and sustainable power source for mobile networks...

  1. 45S rDNA external transcribed spacer organization reveals new phylogenetic relationships in Avena genus.

    Science.gov (United States)

    Rodrigues, Joana; Viegas, Wanda; Silva, Manuela

    2017-01-01

    The genus Avena comprises four distinct genomes organized in diploid (AA or CC), tetraploid (AABB or AACC) and hexaploid species (AACCDD), constituting an interesting model for phylogenetic analysis. The aim of this work was to characterize 45S rDNA intergenic spacer (IGS) variability in distinct species representative of Avena genome diversity-A. strigosa (AA), A. ventricosa (CvCv), A. eriantha (CpCp), A. barbata (AABB), A. murphyi (AACC), A. sativa (AACCDD) and A. sterilis (AACCDD) through the assessment of the 5' external transcribed spacer (5'-ETS), a promising IGS region for phylogenetic studies poorly studied in Avena genus. In this work, IGS length polymorphisms were detected mainly due to distinct 5'-ETS sequence types resulting from major differences in the number and organization of repeated motifs. Although species with A genome revealed a 5'-ETS organization (A-organization) similar to the one previously described in A. sativa, a distinct organization was unraveled in C genome diploid species (C-organization). Interestingly, such new organization presents a higher similarity with other Poaceae species than A-genome sequences, supporting the hypothesis of C-genome being the ancestral Avena genome. Additionally, polyploid species with both genomes mainly retain the A-genome 5'-ETS organization, confirming the preferential elimination of C-genome sequences in Avena polyploid species. Moreover, 5'-ETS sequences phylogenetic analysis consistently clustered the species studied according to ploidy and genomic constitution supporting the use of ribosomal genes to highlight Avena species evolutive pathways.

  2. Cationic gemini surfactants with cleavable spacer: chemical hydrolysis, biodegradation, and toxicity.

    Science.gov (United States)

    Tehrani-Bagha, A R; Holmberg, K; van Ginkel, C G; Kean, M

    2015-07-01

    The paper describes synthesis and characterization of a new type of cationic gemini surfactant, which has dodecyl tails and a spacer that contains an ester bond. The nomenclature used to describe the structure is 12Q2OCO1Q12, with Q being a quaternary ammonium group and the numbers indicating the number of methylene or methyl groups. Due to the close proximity to the two quaternary ammonium groups, the ester bond is very stable on the acid side and very labile already at slightly alkaline conditions. The hydrolysis products are two single chain surfactants (i.e. 12Q2OH and 12Q1COOH) which are less surface active than the intact gemini surfactant. 12Q2OCO1Q12 was found to be readily biodegradable, i.e. it gave more than 60% biodegradation after 28 days. This is interesting because similar gemini surfactants but with ester bonds in the tails instead of the spacer, have previously been found not to be readily biodegradable. The gemini surfactant was found to be toxic to aquatic organisms (ErC50 value of 0.27 mg/l), although less toxic than the two hydrolysis products. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Role of spacer length in interaction between novel gemini imidazolium surfactants and Rhizopus oryzae lipase.

    Science.gov (United States)

    Adak, Sunita; Datta, Sougata; Bhattacharya, Santanu; Banerjee, Rintu

    2015-11-01

    An insight into the effects of new ionic liquid-type gemini imidazolium cationic surfactants on the structure and function of the lipases is of prime importance for their potential application. Changes in the activity, stability and structure of Rhizopus oryzae lipase in the presence of novel gemini surfactants, [C16-3-C16im]Br2 and [C16-12-C16im]Br2 were probed in the present study. Surfactant with shorter spacer length, [C16-3-C16im]Br2 was found to be better in improving the hydrolytic activity and thermal stability of the lipase. For both the surfactants, activation was concentration dependent. CD spectroscopy results showed a decrease in α-helix and an increase in β-sheet content in the presence of these surfactants. A higher structural change observed in presence of [C16-12-C16im]Br2 correlated with lower enzyme activity. Isothermal titration calorimetric studies showed the binding to be spontaneous in nature based on sequential two site binding model. The forces involved in binding were found to differ for the two surfactants proving that the spacer length is an important factor which governs the interaction. These surfactants could be used as promising components both in enzyme modification and media engineering for attaining the desired goals in biocatalytic reactions. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. INTERSPINOUS SPACER IN PERSISTENT DISCOGENIC PAIN: PERCUTANEOUS APPROACH OR OPEN TECHNIQUE

    Directory of Open Access Journals (Sweden)

    José Antonio Cruz Ricardez

    Full Text Available ABSTRACT Objective: To compare the postoperative clinical course of placement of interspinous spacer with open technique (ISO with percutaneous interspinous spacer (PIS. Methods: Quasi-experimental, longitudinal study of 42 patients with discogenic pain uncontrolled with analgesics, aged 35-55 years old, 21 women, and 21 men. Clinical history, location of pain, VAS scale before and after surgery, Oswestry Disability Index and Macnab modified scale at 6 months were used. Results: When performing quantitative analysis statistical significance (p = 0.0478, 0.0466, 0.0399 was demonstrated with Student's t test between the results according to VAS scale; in the qualitative analysis with the Oswestry index and Macnab modified scale it was demonstrated the hypothesis that the results is dependent of the surgical technique. Conclusions: According to the results, we can conclude that there is a statistically significant difference depending on the surgical technique used with respect to the rate of disability and functionality in daily life as well as in the improvement of pain symptoms.

  5. The intergenic spacer region of the rDNA in Haplopappus gracilis (Nutt.) Gray.

    Science.gov (United States)

    Ruffini Castiglione, M; Gelati, M T; Cremonini, R; Frediani, M

    2013-06-01

    In this paper, we provide further information on the genome organisation of Haplopappus gracilis, one of the six angiosperms showing the lowest chromosome number, i.e. 2n = 4, by determining the nucleotide sequence of the intergenic spacer region of the ribosomal RNA genes and its cytological localization on metaphase chromosomes. DNA sequence analysis reveals the occurring of a product of 4,382 bp in length, characterised by the presence of four blocks of different repeated sequences. Our analysis also evidenced putative promoter regions with three transcription initiation sites for polymerase I, as previously reported in Artemisia absinthium, belonging to the same Asteraceae family. A fluorescent in situ hybridization with the intergenic spacer probe indicates the presence of rDNA genes only in the satellited chromosomes of H. gracilis; besides, differences in the signal intensity between homologous chromosomes were frequently observed, thus suggesting for these chromosome sites the presence of a variable number of rDNA gene copies, even if a divergent chromatin organisation in corresponding regions cannot be ruled out.

  6. Two-stage revision of septic knee prosthesis with articulating knee spacers yields better infection eradication rate than one-stage or two-stage revision with static spacers.

    Science.gov (United States)

    Romanò, C L; Gala, L; Logoluso, N; Romanò, D; Drago, L

    2012-12-01

    The best method for treating chronic periprosthetic knee infection remains controversial. Randomized, comparative studies on treatment modalities are lacking. This systematic review of the literature compares the infection eradication rate after two-stage versus one-stage revision and static versus articulating spacers in two-stage procedures. We reviewed full-text papers and those with an abstract in English published from 1966 through 2011 that reported the success rate of infection eradication after one-stage or two-stage revision with two different types of spacers. In all, 6 original articles reporting the results after one-stage knee exchange arthoplasty (n = 204) and 38 papers reporting on two-stage revision (n = 1,421) were reviewed. The average success rate in the eradication of infection was 89.8% after a two-stage revision and 81.9% after a one-stage procedure at a mean follow-up of 44.7 and 40.7 months, respectively. The average infection eradication rate after a two-stage procedure was slightly, although significantly, higher when an articulating spacer rather than a static spacer was used (91.2 versus 87%). The methodological limitations of this study and the heterogeneous material in the studies reviewed notwithstanding, this systematic review shows that, on average, a two-stage procedure is associated with a higher rate of eradication of infection than one-stage revision for septic knee prosthesis and that articulating spacers are associated with a lower recurrence of infection than static spacers at a comparable mean duration of follow-up. IV.

  7. Flow resistance of orifices and spacers of BWR thermal-hydraulic and neutronic coupling loop

    International Nuclear Information System (INIS)

    Iguchi, Tadashi; Asaka, Hideaki; Nakamura, Hideo

    2002-03-01

    Authors are performing THYNC experiments to study thermal-hydraulic instability under neutronic and thermal-hydraulic coupling. In THYNC experiments, the orifices are installed at the exit of the test section and the spacers are installed in the test section, in order to properly simulate in-core thermal-hydraulics in the reactor core. It is necessary to know the flow resistance of the orifices and spacers for the analysis of THYNC experimental results. Consequently, authors measured the flow resistance of orifice and spacer under single-phase and two-phase flows. Using the experimental results, authors investigated the dependency of the flow resistances on the parameters, such as pressure, mass flux, an geometries. Furthermore, authors investigated the applicability of the basic two-phase flow models, for example the separate flow model, to the two-phase flow multiplier. As the result of the investigation on the single-phase flow experiment, it was found (1) that the effects of pressure and mass flux flow resistance are described by a function of Reynolds number, and (2) that flow resistances of the orifice and the spacer are calculated with the previous prediction methods. However, it was necessary to introduce an empirical coefficient, since it was difficult to predict accurately the flow resistance only with the previous prediction method due to the complicated geometry dependency, for example a flow area blockage ratio. On the other hand, according to the investigation on two-phase flow experiment, the followings were found. (1) Relation between the two-phase flow multiplier and the quality is regarded to be linear under pressure of 2MPa - 7MPa. The relation is dependent on pressure and geometry, and is little dependent on mass flux. (2) Relation between the two-phase flow multiplier and void fraction is little dependent on pressure, mass flux, and geometry under pressure of 0.2MPa - 7MPa and void fraction less than 0.6. The relation is less dependent on

  8. Structural Mobility, Exchange Mobility and Subgroup Consistent Mobility Measurement – US–German Mobility Measurements Revisited

    OpenAIRE

    C. SCHLUTER; D. VAN DE GAER

    2008-01-01

    We formalize the concept of structural mobility and use the framework of subgroup consistent mobility measurement to derive a relative and an absolute measure of mobility that is increasing both in upward structural mobility and exchange mobility. In our empirical illustration, we contribute substantively to the ongoing debate about mobility rankings between the USA and Germany.

  9. Vibrational modes and strain in GaN/AlN quantum dot stacks: dependence on spacer thickness

    Energy Technology Data Exchange (ETDEWEB)

    Fresneda, J.; Cros, A.; Llorens, J.M.; Garcia-Cristobal, A.; Cantarero, A. [Institut de Ciencia del Materials, Universitat de Valencia, 46071 Valencia (Spain); Amstatt, B.; Bellet-Amalric, E.; Daudin, B. [CEA-CNRS Group, Nanophysique et Semiconducteurs, DRFMC/SP2M/PSC, CEA-Grenoble, 17 rue des Martyrs, 38054 Grenoble cedex 9 (France)

    2007-06-15

    We have investigated the influence of spacer thickness on the vibrational and strain characteristics of GaN/AlN quantum dot multilayers (QD). The Raman shift corresponding to the E{sub 2h} vibrational mode related to the QDs has been analyzed for AlN thicknesses ranging from 4.4 nm to 13 nm, while the amount of GaN deposited in each layer remained constant from sample to sample. It is shown that there is a rapid blue shift of the GaN vibrational mode with spacer thickness when its value is smaller than 7 nm while it remains almost constant for thicker spacers. A rapid increase of the Raman line-width in the thicker samples is also observed. The experimental behavior is discussed in comparison with the results of a theoretical model for the strain in the QDs. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  10. Mutations in Cas9 Enhance the Rate of Acquisition of Viral Spacer Sequences during the CRISPR-Cas Immune Response.

    Science.gov (United States)

    Heler, Robert; Wright, Addison V; Vucelja, Marija; Bikard, David; Doudna, Jennifer A; Marraffini, Luciano A

    2017-01-05

    CRISPR loci and their associated (Cas) proteins encode a prokaryotic immune system that protects against viruses and plasmids. Upon infection, a low fraction of cells acquire short DNA sequences from the invader. These sequences (spacers) are integrated in between the repeats of the CRISPR locus and immunize the host against the matching invader. Spacers specify the targets of the CRISPR immune response through transcription into short RNA guides that direct Cas nucleases to the invading DNA molecules. Here we performed random mutagenesis of the RNA-guided Cas9 nuclease to look for variants that provide enhanced immunity against viral infection. We identified a mutation, I473F, that increases the rate of spacer acquisition by more than two orders of magnitude. Our results highlight the role of Cas9 during CRISPR immunization and provide a useful tool to study this rare process and develop it as a biotechnological application. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Steady-state, local temperature fields with turbulent liquid sodium flow in nominal and disturbed bundle geometries with spacer grids

    International Nuclear Information System (INIS)

    Moeller, R.; Tschoeke, H.

    1980-01-01

    The operating reliability of nuclear reactors calls for a reliable strength analysis of the highly loaded core elements, one of its prerequisites being the reliable determination of the three-dimensional velocity and temperature fields. To verify thermohydraulics computer programs, extensive local temperature measurements in the rod claddings of the critical bundle zone were performed on a heated 19-rod bundle model with sodium flow and provided with spacer grids (P/D = 1.30; W/D = 1.19). The essential results are: - Outside the spacer grids, the azimuthal temperature variations of the side and corner rods are approximately 10-fold those of rods in the central bundle zone. - The spacer grids investigated give rise to great local temperature peaks and correspondingly great temperature gradients in the axial and azimuthal directions immediately around the support points. - Continuous reduction of a subchannel by rod bowing results in substantial rises of temperature which, however, are limited to adjacent cladding tubes. (orig.)

  12. Invariance of the magnetic behavior and AMI in ferromagnetic biphase films with distinct non-magnetic metallic spacers

    Energy Technology Data Exchange (ETDEWEB)

    Silva, E.F. [Departamento de Física, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil); Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife, PE (Brazil); Gamino, M. [Departamento de Física, Universidade Federal de Pernambuco, 50670-901 Recife, PE (Brazil); Instituto de Física, Universidade Federal do Rio Grande de Sul, 91501-970 Porto Alegre, RS (Brazil); Andrade, A.M.H. de [Instituto de Física, Universidade Federal do Rio Grande de Sul, 91501-970 Porto Alegre, RS (Brazil); Vázquez, M. [Instituto de Ciencia de Materiales de Madrid, CSIC, 28049 Madrid (Spain); Correa, M.A. [Departamento de Física, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil); Bohn, F., E-mail: felipebohn@fisica.ufrn.br [Departamento de Física, Universidade Federal do Rio Grande do Norte, 59078-900 Natal, RN (Brazil)

    2017-02-01

    We investigate the quasi-static magnetic, magnetotransport, and dynamic magnetic properties in ferromagnetic biphase films with distinct non-magnetic metallic spacer layers. We observe that the nature of the non-magnetic metallic spacer material does not have significant influence on the overall biphase magnetic behavior, and, consequently, on the magnetotransport and dynamic magnetic responses. We focus on the magnetoimpedance effect and verify that the films present asymmetric magnetoimpedance effect. Moreover, we explore the possibility of tuning the linear region of the magnetoimpedance curves around zero magnetic field by varying the probe current frequency in order to achieve higher sensitivity values. The invariance of the magnetic behavior and the asymmetric magnetoimpedance effect in ferromagnetic biphase films with distinct non-magnetic metallic spacers place them as promising candidates for probe element and open possibilities to the development of lower-cost high sensitivity linear magnetic field sensor devices.

  13. Multi-Scaled Modeling the Mechanical Properties of Tubular Composites Reinforced with Innovated 3D Weft Knitted Spacer Fabrics

    Science.gov (United States)

    Omrani, Elahe; Hasani, Hossein; Dibajian, Sayed Houssain

    2018-02-01

    Textile composites of 3D integrated spacer configurations have been recently focused by several researchers all over the world. In the present study, newly-designed tubular composites reinforced with 3D spacer weft knitted fabrics were considered and the effects of their structural parameters on some applicable mechanical properties were investigated. For this purpose, two different samples of 3D spacer weft knitted textile types in tubular form were produced on an electronic flat knitting machine, using glass/nylon hybrid yarns. Thermoset tubular-shaped composite parts were manufactured via vacuum infusion molding process using epoxy resin. The mechanical properties of the produced knitted composites in term of external static and internal hydrostatic pressures were evaluated. Resistance of the produced composites against the external static and internal hydrostatic pressures was numerically simulated using multi-scale modeling method. The finding revealed that there is acceptable correlation between experimental and theoretical results.

  14. The Effect of Subluxation of Articulating Antibiotic Spacers on Bone Defects and Degree of Constraint in Revision Knee Arthroplasty.

    Science.gov (United States)

    Lau, Adrian C K; Howard, James L; Macdonald, Steven J; Teeter, Matthew G; Lanting, Brent A

    2016-01-01

    This study investigated whether subluxation of articulating antibiotic spacers is associated with the bone defects found and constraint required when re-implanting the knee arthroplasty components. Staged revisions for infections of primary total knee arthroplasties between 2004 and 2012 were examined. Radiographic sagittal and coronal subluxations of 72 knees were measured prior to second stage revision. Coronal subluxation was found to be associated with increased requirement for constrained knee systems (P<0.035). Sagittal subluxation was associated with greater tibia bone defects (P<0.037). Careful surgical technique and monitoring of articulating spacers should be done to avoid subluxation after stage 1 revision. If subluxation of the articulating spacer is present, constrained revision knee systems as well as augments should be available at time of re-implantation. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Parylene C-on-photoresist (POP): a low temperature spacer scheme for polymer/metal nanowire fabrication

    International Nuclear Information System (INIS)

    Li, Yuanhui; Xie, Quan; Wang, Wei; Zhang, Hao; Lei, Yinhua; Zhang, Haixia Alice; Wu, Wengang; Li, Zhihong; Zheng, Mingxin

    2011-01-01

    This work introduced a novel spacer scheme for polymer/metal nanowire preparation by combining Parylene C and photoresist (Parylene C on photoresist, POP, process), both of which possess a low temperature fabrication essence. Adhesion between the Parylene C and the substrate with photoresist onside was improved by introducing a modified silanization pretreatment. Parylene C filled in an undercut generated by regular lithography on a dual-layered photoresist was left as nanometer-sized residues after an isotropic oxygen plasma etching. Parylene C nanowires with the minimal width down to 200 nm were successfully obtained by this POP-based spacer technique, and were then utilized as the etching mask for ion milling of the metal films beneath to realize corresponding chromium/gold nanowires. The present POP scheme will expand the application of the spacer technique in polymer/metal nanowire fabrication for integrated micro/nanoelectromechanical systems. (technical note)

  16. Senescent vs. non-senescent cells in the human annulus in vivo: Cell harvest with laser capture microdissection and gene expression studies with microarray analysis

    Directory of Open Access Journals (Sweden)

    Ingram Jane A

    2010-01-01

    Full Text Available Abstract Background Senescent cells are well-recognized in the aging/degenerating human disc. Senescent cells are viable, cannot divide, remain metabolically active and accumulate within the disc over time. Molecular analysis of senescent cells in tissue offers a special challenge since there are no cell surface markers for senescence which would let one use fluorescence-activated cell sorting as a method for separating out senescent cells. Methods We employed a novel laser capture microdissection (LCM design to selectively harvest senescent and non-senescent annulus cells in paraffin-embedded tissue, and compared their gene expression with microarray analysis. LCM was used to separately harvest senescent and non-senescent cells from 11 human annulus specimens. Results Microarray analysis revealed significant differences in expression levels in senescent cells vs non-senescent cells: 292 genes were upregulated, and 321 downregulated. Genes with established relationships to senescence were found to be significantly upregulated in senescent cells vs. non-senescent cells: p38 (MPAK14, RB-Associated KRAB zinc finger, Discoidin, CUB and LCCL domain, growth arrest and DNA-damage inducible beta, p28ING5, sphingosine-1-phosphate receptor 2 and somatostatin receptor 3; cyclin-dependent kinase 8 showed significant downregulation in senescent cells. Nitric oxidase synthase 1, and heat shock 70 kDa protein 6, both of which were significantly down-regulated in senescent cells, also showed significant changes. Additional genes related to cytokines, cell proliferation, and other processes were also identified. Conclusions Our LCM-microarray analyses identified a set of genes associated with senescence which were significantly upregulated in senescent vs non-senescent cells in the human annulus. These genes include p38 MAP kinase, discoidin, inhibitor of growth family member 5, and growth arrest and DNA-damage-inducible beta. Other genes, including genes

  17. Diversity and Inheritance of Intergenic Spacer Sequences of 45S Ribosomal DNA among Accessions of Brassica oleracea L. var. capitata

    Directory of Open Access Journals (Sweden)

    Kiwoung Yang

    2015-12-01

    Full Text Available Ribosomal DNA (rDNA of plants is present in high copy number and shows variation between and within species in the length of the intergenic spacer (IGS. The 45S rDNA of flowering plants includes the 5.8S, 18S and 25S rDNA genes, the internal transcribed spacer (ITS1 and ITS2, and the intergenic spacer 45S-IGS (25S-18S. This study identified six different types of 45S-IGS, A to F, which at 363 bp, 1121 bp, 1717 bp, 1969 bp, 2036 bp and 2111 bp in length, respectively, were much shorter than the reported reference IGS sequences in B. oleracea var. alboglabra. The shortest two IGS types, A and B, lacked the transcription initiation site, non-transcribed spacer, and external transcribed spacer. Functional behavior of those two IGS types in relation to rRNA synthesis is a subject of further investigation. The other four IGSs had subtle variations in the transcription termination site, guanine-cytosine (GC content, and number of tandem repeats, but the external transcribed spacers of these four IGSs were quite similar in length. The 45S IGSs were found to follow Mendelian inheritance in a population of 15 F1s and their 30 inbred parental lines, which suggests that these sequences could be useful for development of new breeding tools. In addition, this study represents the first report of intra-specific (within subspecies variation of the 45S IGS in B. oleracea.

  18. Diversity and Inheritance of Intergenic Spacer Sequences of 45S Ribosomal DNA among Accessions of Brassica oleracea L. var. capitata.

    Science.gov (United States)

    Yang, Kiwoung; Robin, Arif Hasan Khan; Yi, Go-Eun; Lee, Jonghoon; Chung, Mi-Young; Yang, Tae-Jin; Nou, Ill-Sup

    2015-12-03

    Ribosomal DNA (rDNA) of plants is present in high copy number and shows variation between and within species in the length of the intergenic spacer (IGS). The 45S rDNA of flowering plants includes the 5.8S, 18S and 25S rDNA genes, the internal transcribed spacer (ITS1 and ITS2), and the intergenic spacer 45S-IGS (25S-18S). This study identified six different types of 45S-IGS, A to F, which at 363 bp, 1121 bp, 1717 bp, 1969 bp, 2036 bp and 2111 bp in length, respectively, were much shorter than the reported reference IGS sequences in B. oleracea var. alboglabra. The shortest two IGS types, A and B, lacked the transcription initiation site, non-transcribed spacer, and external transcribed spacer. Functional behavior of those two IGS types in relation to rRNA synthesis is a subject of further investigation. The other four IGSs had subtle variations in the transcription termination site, guanine-cytosine (GC) content, and number of tandem repeats, but the external transcribed spacers of these four IGSs were quite similar in length. The 45S IGSs were found to follow Mendelian inheritance in a population of 15 F₁s and their 30 inbred parental lines, which suggests that these sequences could be useful for development of new breeding tools. In addition, this study represents the first report of intra-specific (within subspecies) variation of the 45S IGS in B. oleracea.

  19. Porosity of spacer-filled channels in spiral-wound membrane systems: Quantification methods and impact on hydraulic characterization.

    Science.gov (United States)

    Siddiqui, A; Lehmann, S; Haaksman, V; Ogier, J; Schellenberg, C; van Loosdrecht, M C M; Kruithof, J C; Vrouwenvelder, J S

    2017-08-01

    The porosity of spacer-filled feed channels influences the hydrodynamics of spiral-wound membrane systems and impacts the overall performance of the system. Therefore, an exact measurement and a detailed understanding of the impact of the feed channel porosity is required to understand and improve the hydrodynamics of spiral-wound membrane systems applied for desalination and wastewater reuse. The objectives of this study were to assess the accuracy of porosity measurement techniques for feed spacers differing in geometry and thickness and the consequences of using an inaccurate method on hydrodynamic predictions, which may affect permeate production. Six techniques were applied to measure the porosity namely, three volumetric techniques based on spacer strand count together with a cuboidal (SC), cylindrical (VCC) and ellipsoidal volume calculation (VCE) and three independent techniques based on volume displacement (VD), weight and density (WD) and computed tomography (CT) scanning. The CT method was introduced as an alternative for the other five already existing and applied methods in practice. Six feed spacers used for the porosity measurement differed in filament thickness, angle between the filaments and mesh-size. The results of the studies showed differences between the porosities, measured by the six methods. The results of the microscopic techniques SC, VCC and VCE deviated significantly from measurements by VD, WD and CT, which showed similar porosity values for all spacer types. Depending on the maximum deviation of the porosity measurement techniques from -6% to +6%, (i) the linear velocity deviations were -5.6% and +6.4% respectively and (ii) the pressure drop deviations were -31% and +43% respectively, illustrating the importance of an accurate porosity measurement. Because of the accuracy and standard deviation, the VD and WD method should be applied for the porosity determination of spacer-filled channels, while the CT method is recommended

  20. Investigation of optical spacer layers from solution based precursors for polymer solar cells using X-ray reflectometry

    DEFF Research Database (Denmark)

    Andersen, Philip Hvidthøft Delff; Skårhøj, Jakob; Andreasen, Jens Wenzel

    2009-01-01

    Optical spacer layers based on titaniumalkoxide precursor solutions were prepared by spin-coating on top of bulk heterojunction layers based on poly-3-hexylthiophene (P3HT) and phenyl-C61-butyric acid methylester (PCBM). Models and experiment have shown that the performance of polymer solar cells...... can improve upon application of an optical spacer by shifting the maximum of the electrical field vector of the incident light into the active layer. This avoids the so called “dead zone” close to the reflective electrode. We demonstrate a simple linear model that can be used to predict the intensity...

  1. Porosity of spacer-filled channels in spiral-wound membrane systems: Quantification methods and impact on hydraulic characterization

    KAUST Repository

    Siddiqui, Amber

    2017-04-13

    The porosity of spacer-filled feed channels influences the hydrodynamics of spiral-wound membrane systems and impacts the overall performance of the system. Therefore, an exact measurement and a detailed understanding of the impact of the feed channel porosity is required to understand and improve the hydrodynamics of spiral-wound membrane systems applied for desalination and wastewater reuse. The objectives of this study were to assess the accuracy of porosity measurement techniques for feed spacers differing in geometry and thickness and the consequences of using an inaccurate method on hydrodynamic predictions, which may affect permeate production. Six techniques were applied to measure the porosity namely, three volumetric calculations based on spacer strand count together with cuboidal (SC), cylindrical (VCC) and ellipsoidal volume calculation (VCE) and three independent techniques based on volume displacement (VD), weight and density (WD) and computed tomography scanning (CT). The CT method was introduced as an alternative for the other five already existing and applied methods in practice.Six feed spacers used for the porosity measurement differed in filament thickness, angle between the filaments and mesh-size. The results of the studies showed differences between the porosities, measured by the six methods. The results of the microscopic techniques SC, VCC and VCE deviated significantly from measurements by VD, WD and CT, which showed similar porosity values for all spacer types.Depending on the maximum deviation of the porosity measurement techniques from –6% to +6%, (i) the linear velocity deviations were −5.6% and +6.4% respectively and (ii) the pressure drop deviations were –31% and +43% respectively, illustrating the importance of an accurate porosity measurement. Because of the accuracy and standard deviation, the VD and WD method should be applied for the porosity determination of spacer-filled channels, while the CT method is recommended for

  2. Mobile Marketing

    OpenAIRE

    Luengo Cascudo, Alberto

    2010-01-01

    El principal objetivo de este proyecto es explicar y entender la importancia del Mobile Marketing como nueva herramienta de negocio en el Marketing empresarial. Para ello, el primer objetivo es entender los dos factores que para mí son la clave de su importancia: la evolución del entorno tecnológico y el cambio en los hábitos del consumidor. Debido a la novedad de esta nueva forma de Marketing y al hecho de que está en constante definición, es básico exponer de la forma más cla...

  3. Designing Mobilities

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    movements of people, goods, and information 'from A to B'. Accordingly, the way people, goods, and information moves shapes the way we understand our built environment, other consociates, and ourselves. The book contributes with a new and critical-creative gaze on what might seem to be trivial and mundane...... acts of moving in the city. 'Designing Mobilities' is based on more than a decade of academic research by Professor of Urban Theory, Ole B. Jensen and a must-read for students and scholars with an interest in urban studies, urban design, architecture, urban planning, transport planning and geography...

  4. Downwardly mobile

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-01-01

    P & H Mining Equipment has produced the 250XP rotary blasthole drill, its first `clean sheet` drill after eight years of upgrading the line of large rotaries it acquired from Gardner Denver in 1991. A prototype has been working on an Australian coal mine since June 1998. A further two units of the 250XP are being erected at a diamond mine in Botswana for start-up in January 1999 and another will begin drilling at a Wyoming, USA coal mine in February. The drill is a highly mobile, heavy duty, highly reliable diesel/hydraulic drill weighing 113,500 kg and can drill holes at angles up to 30 degrees.

  5. Role of the tricuspid annulus and the eustachian valve/ridge on atrial flutter. Relevance to catheter ablation of the septal isthmus and a new technique for rapid identification of ablation success

    NARCIS (Netherlands)

    Nakagawa, H.; Lazzara, R.; Khastgir, T.; Beckman, K. J.; McClelland, J. H.; Imai, S.; Pitha, J. V.; Becker, A. E.; Arruda, M.; Gonzalez, M. D.; Widman, L. E.; Rome, M.; Neuhauser, J.; Wang, X.; Calame, J. D.; Goudeau, M. D.; Jackman, W. M.

    1996-01-01

    Typical atrial flutter (AFL) results from right atrial reentry by propagation through an isthmus between the inferior vena cava (IVC) and tricuspid annulus (TA). We postulated that the eustachian valve and ridge (EVR) forms a line of conduction block between the IVC and coronary sinus (CS) ostium

  6. Minimally invasive treatment of lumbar spinal stenosis with a novel interspinous spacer

    Directory of Open Access Journals (Sweden)

    Shabat S

    2011-09-01

    Full Text Available Shay Shabat1, Larry E Miller2,3, Jon E Block3, Reuven Gepstein11Spinal Care Unit, Sapir Medical Center, Kfar Saba, Israel; 2Miller Scientific Consulting, Inc, Biltmore Lake, NC, USA; 3Jon E Block, PhD, Inc, San Francisco, CA, USAPurpose: To assess the safety and effectiveness of a novel, minimally invasive interspinous spacer in patients with moderate lumbar spinal stenosis (LSS.Methods: A total of 53 patients (mean age, 70 ± 11 years; 45% female with intermittent neurogenic claudication secondary to moderate LSS, confirmed on imaging studies, were treated with the Superion® Interspinous Spacer (VertiFlex, Inc, San Clemente, CA and returned for follow-up visits at 6 weeks, 1 year, and 2 years. Study endpoints included axial and extremity pain severity with an 11-point numeric scale, Zurich Claudication Questionnaire (ZCQ, back function with the Oswestry Disability Index (ODI, health-related quality of life with the Physical Component Summary (PCS and Mental Component Summary (MCS scores from the SF-12, and adverse events.Results: Axial and extremity pain each decreased 54% (both P < 0.001 over the 2-year follow-up period. ZCQ symptom severity scores improved 43% (P < 0.001 and ZCQ physical function improved 44% (P < 0.001 from pre-treatment to 2 years post-treatment. A statistically significant 50% improvement (P < 0.001 also was noted in back function. PCS and MCS each improved 40% (both P < 0.001 from pre-treatment to 2 years. Clinical success rates at 2 years were 83%–89% for ZCQ subscores, 75% for ODI, 78% for PCS, and 80% for MCS. No device infection, implant breakage, migration, or pull-out was observed, although two (3.8% patients underwent explant with subsequent laminectomy.Conclusion: Moderate LSS can be effectively treated with a minimally invasive interspinous spacer. This device is appropriate for select patients who have failed nonoperative treatment measures for LSS and meet strict anatomical criteria.Keywords: Superion, axial

  7. Expression of the vitamin D metabolizing enzyme CYP24A1 at the annulus of human spermatozoa may serve as a novel marker of semen quality

    DEFF Research Database (Denmark)

    Jensen, Martin Blomberg; Jørgensen, A; Nielsen, J E

    2012-01-01

    Vitamin D (VD) is important for male reproduction in mammals and the VD receptor (VDR) and VD-metabolizing enzymes are expressed in human spermatozoa. The VD-inactivating enzyme CYP24A1 titrates the cellular responsiveness to VD, is transcriptionally regulated by VD, and has a distinct expression...... at the sperm annulus. Here, we investigated if CYP24A1 expression serves as a marker for VD metabolism in spermatozoa, and whether CYP24A1 expression was associated with semen quality. We included 130 men (53 healthy young volunteers and 77 subfertile men) for semen analysis and immunocytochemical (ICC......% of the spermatozoa from young men. The median number of CYP24A1-expressing spermatozoa was 1% in subfertile men and thus significantly (p 3% CYP24A1-positive spermatozoa distinguished young men from subfertile men with a sensitivity of 66.0%, a specificity of 77.9% and a positive predictive value of 98...

  8. Variable magnetic field (VMF) effect on the heat transfer of a half-annulus cavity filled by Fe3O4-water nanofluid under constant heat flux

    Science.gov (United States)

    Hatami, M.; Zhou, J.; Geng, J.; Jing, D.

    2018-04-01

    In this paper, the effect of a variable magnetic field (VMF) on the natural convection heat transfer of Fe3O4-water nanofluid in a half-annulus cavity is studied by finite element method using FlexPDE commercial code. After deriving the governing equations and solving the problem by defined boundary conditions, the effects of three main parameters (Hartmann Number (Ha), nanoparticles volume fraction (φ) and Rayleigh number (Ra)) on the local and average Nusselt numbers of inner wall are investigated. As a main outcome, results confirm that in low Eckert numbers, increasing the Hartmann number make a decrease on the Nusselt number due to Lorentz force resulting from the presence of stronger magnetic field.

  9. [Effects of electroacupuncture on Wnt-β-catenin signal pathway in annulus fibrosus cells in intervertebral disc in rats with cervical spondylosis].

    Science.gov (United States)

    Liao, Jun; Xie, Qiao-Yu; Zhang, Le; Ke, Mei-Gui

    2014-12-01

    To observe the effects of electroacupuncture (EA) at "Dazhui" (GV 14) on Wnt-β-catenin signal pathway in annulus fibrosus cells in intervertebral disc in rats with cervical spondylosis. Forty SD rats were randomized into a control group, a model group, an EA group and a medication group, 10 rats in each one. Rats in the control group were treated with sham operation, only incision on local skin; rats in the remaining groups were made into cervical spondylosis models. After model establishment, rats in the control group and model group received fixed treatment under identical condition; rats in the EA group were treated with EA at "Dazhui" (GV 14), 30 min per treatment; rats in the medication group were treated with intragastric administration of meloxicam tablets. Treatments were both given once a day, and 14 days were taken as one session; there was an interval of 2 days between two sessions, and totally two sessions were given. After the treatments, immunohistochemistry was applied to measure the expression of Wnt, glycogen synthase kinase-3β (GSK-3β) and Axin in annulus fibrosus cells; western blot was used to test the expression of P-β-catenin. In the control group, there were more positive cells of Wnt, GSK-3β and Axin, which were intensively distributed, deeply colored, and strongly positive; In the model group, there were less positive cells of Wnt, GSK-3β and Axin, which were sparsely distributed and weakly positive. The expression of Wnt, GSK-3β, Axin and P-β-catenin in the model group was less than that in the control group (all P 0.05). EA could delay the degeneration of intervertebral disc, which may be related to EA inhibiting signal pathway of Wnt-β-catenin.

  10. CFD prediction of flow and phase distribution in fuel assemblies with spacers

    Energy Technology Data Exchange (ETDEWEB)

    Anglart, H.; Nylund, O. [ABB Atom AB, Vasteras (Switzerland); Kurul, N. [Rensselaer Polytechnic Institute, Troy, NY (United States)] [and others

    1995-09-01

    This paper is concerned with the modeling and computation of multi-dimensional two-phase flows in BWR fuel assemblies. The modeling principles are presented based on using a two-fluid model in which lateral interfacial effects are accounted for. This model has been used to evaluate the velocity fields of both vapor and liquid phases, as well as phase distribution, between fuel elements in geometries similar to BWR fuel bundles. Furthermore, this model has been used to predict, in a detailed mechanistic manner, the effects of spacers on flow and phase distribution between, and pressure drop along, fuel elements. The related numerical simulations have been performed using a CFD computer code, CFDS-FLOW3D.

  11. Sequence organization of the Acanthamoeba rRNA intergenic spacer: identification of transcriptional enhancers.

    Science.gov (United States)

    Yang, Q; Zwick, M G; Paule, M R

    1994-01-01

    The primary sequence of the entire 2330 bp intergenic spacer of the A.castellanii ribosomal RNA gene was determined. Repeated sequence elements averaging 140 bp were identified and found to bind a protein required for optimum initiation at the core promoter. These repeated elements were shown to stimulate rRNA transcription by RNA polymerase I in vitro. The repeats inhibited transcription when placed in trans, and stimulated transcription when in cis, in either orientation, but only when upstream of the core promoter. Thus, these repeated elements have characteristics similar to polymerase I enhancers found in higher eukaryotes. The number of rRNA repeats in Acanthamoeba cells was determined to be 24 per haploid genome, the lowest number so far identified in any eukaryote. However, because Acanthamoeba is polyploid, each cell contains approximately 600 rRNA genes. Images PMID:7984432

  12. Nasal inhalation of budesonide from a spacer in children with perennial rhinitis and asthma

    DEFF Research Database (Denmark)

    Pedersen, W; Hjuler, Inga Merete; Bisgaard, H

    1998-01-01

    The standard treatment of allergic rhinitis and asthma consists of topical corticosteroids administered intranasally and inhaled through the mouth. Although this therapy is highly effective, and side-effects are few and mild, it may be possible further to improve the therapeutic index and patient...... compliance with the treatment. In the present study, we evaluated a nasal inhalation system used for the simultaneous treatment of rhinitis and asthma. In principle, it results in an airway deposition of the corticosteroid similar to that of inhaled allergens. Twenty-four children with perennial rhinitis...... and asthma inhaled budesonide through the nose from a pressurized aerosol, attached to a spacer device, in a double-blind, placebo-controlled, crossover study. Compared with placebo, budesonide treatment resulted in a significant reduction of nasal symptoms (Pasthma symptoms (P

  13. Measurement of paint-on die spacers used for casting relief.

    Science.gov (United States)

    Campagni, W V; Preston, J D; Reisbick, M H

    1982-06-01

    Three paints used for die spacing were measured for film thickness. Two of the materials are marketed as die spacers, and the third is sold as a model airplane paint. The materials were applied to stone dies in multiple coats. They were embedded in resin, sectioned, and measured photographically through a microscope. The three die spacing materials were capable of achieving clinically acceptable relief in the range of 20 to 40 mu by using a variable number of coats. Different paints produced different thicknesses. The two paints sold specifically for die spacing gave 11 to 13 mu per coat. The hobby shop paint had the smallest film thickness per coat, yielding approximately 5 mu per layer. It also had the smallest standard deviation. This control plus the relative low cost and availabilty make it attractive for this purpose.

  14. Clinical observation on the reconstruction of large areas lower eyelid defect with Medpor spacer graft

    Directory of Open Access Journals (Sweden)

    Hai-Yan Li

    2014-08-01

    Full Text Available AIM: To observe the effects of porous polyethylene(Medporas a spacer graft in the reconstruction of large areas eyelid defect after the operation of malignant tumors of lower eyelids.METHODS: Nineteen cases(19 eyesof malignant tumors of lower eyelid underwent the eyelid reconstruction were selected. Medpor lower eyelid inserts implantation were used to replace tarsal joint sliding conjunctival flap and pedicle flap, and repaired full-thickness lower eyelid defects then underwent eyelid reconstruction. RESULTS: Appearance of eyelids and functional improvements were satisfactory with no stimulation on the eyeball and no effect on the visual function. Implants is with no absorption, shift, exclusion or infection and no tumor recurrence in all cases during the follow up for 6-36mo.CONCLUSION: Medpor lower eyelid inserts implantation can instead tarsal plate for the reconstruction of medium to large areas lower eyelid defect, which is easy performing with rare complications. It is an ideal alternatives of tarsal plate.

  15. Optimisation of automated ribosomal intergenic spacer analysis for the estimation of microbial diversity in fynbos soil

    Directory of Open Access Journals (Sweden)

    Karin Jacobs

    2010-07-01

    Full Text Available Automated ribosomal intergenic spacer analysis (ARISA has become a commonly used molecular technique for the study of microbial populations in environmental samples. The reproducibility and accuracy of ARISA, with and without the polymerase chain reaction (PCR are important aspects that influence the results and effectiveness of these techniques. We used the primer set ITS4/ITS5 for ARISA to assess the fungal community composition of two sites situated in the Sand Fynbos. The primer set proved to deliver reproducible ARISA profiles of the fungal community composition with little variation observed between ARISA-PCRs. Variation that occurred in a sample due to repeated DNA extraction is expected for ecological studies. This reproducibility made ARISA a useful tool for the assessment and comparison of diversity in ecological samples. In this paper, we also offered particular suggestions concerning the binning strategy for the analysis of ARISA profiles.

  16. Preparation of the spacer for narrow electrode gap configuration in ionization-based gas sensor

    Energy Technology Data Exchange (ETDEWEB)

    Saheed, Mohamed Shuaib Mohamed; Mohamed, Norani Muti; Burhanudin, Zainal Arif [Electrical and Electronic Engineering, Universiti Teknologi PETRONAS, Seri Iskandar, Tronoh, Perak. (Malaysia); Fundamental and Applied Science, Universiti Teknologi PETRONAS, Seri Iskandar, Tronoh, Perak. (Malaysia); Electrical and Electronic Engineering, Universiti Teknologi PETRONAS, Seri Iskandar, Tronoh, Perak. (Malaysia)

    2012-09-26

    Carbon nanotubes (CNTs) have started to be developed as the sensing element for ionization-based gas sensors due to the demand for improved sensitivity, selectivity, stability and other sensing properties beyond what can be offered by the conventional ones. Although these limitations have been overcome, the problems still remain with the conventional ionization-based gas sensors in that they are bulky and operating with large breakdown voltage and high temperature. Recent studies have shown that the breakdown voltage can be reduced by using nanostructured electrodes and narrow electrode gap. Nanostructured electrode in the form of aligned CNTs array with evenly distributed nanotips can enhance the linear electric field significantly. The later is attributed to the shorter conductivity path through narrow electrode gap. The paper presents the study on the design consideration in order to realize ionization based gas sensor using aligned carbon nanotubes array in an optimum sensor configuration with narrow electrode gap. Several deposition techniques were studied to deposit the spacer, the key component that can control the electrode gap. Plasma spray deposition, electron beam deposition and dry oxidation method were employed to obtain minimum film thickness around 32 {mu}m. For plasma spray method, sand blasting process is required in order to produce rough surface for strong bonding of the deposited film onto the surface. Film thickness, typically about 39 {mu}m can be obtained. For the electron beam deposition and dry oxidation, the film thickness is in the range of nanometers and thus unsuitable to produce the spacer. The deposited multilayer film consisting of copper, alumina and ferum on which CNTs array will be grown was found to be removed during the etching process. This is attributed to the high etching rate on the thin film which can be prevented by reducing the rate and having a thicker conductive copper film.

  17. Analysis of a ribosomal DNA intergenic spacer region from the yellow fever mosquito, Aedes aegypti.

    Science.gov (United States)

    Wu, C C; Fallon, A M

    1998-02-01

    We have sequenced the 1.8 kb intergenic spacer (IGS) region from an Aedes aegypti ribosomal DNA repeat and have identified conserved functional motifs shared with the related mosquito, Aedes albopictus. Despite the shorter length and greater homogeneity of the Ae. aegypti IGS region, the sequences of two potential RNA polymerase I core promoters and closely associated terminator elements were highly conserved. Primer extension analysis indicated that the predominant transcription initiation site in the Ae. aegypti rDNA repeat unit region lay at or near the A residue at nucleotide position 1003 in the 'upstream' RNA polymerase I promoter. This observation was supported by the higher sequence identity between the upstream promoters in Ae. aegypti and Ae. albopictus, relative to the downstream promoters. In contrast to strong similarities among proximal regulatory elements, the Ae. aegypti IGS sequence upstream of the transcription initiation site lacked the ordered array of contiguous approximately 200 nucleotide subrepeats previously found in the IGS of Ae. albopictus. In Ae. aegypti, only 4 approximately 50 nucleotide R subrepeats separated by unique sequences, followed by 2 approximately 50 nucleotide E subrepeats, occurred upstream of the transcription initiation site. Despite their differences in size and sequence, however, the four Ae. aegypti R subrepeats shared an internal structural organization that included a conserved core with 'spacer' promoters and recombinogenic elements similar to those in the longer Ae. albopictus subrepeats. These observations provide an important basis for further characterization of transcription specificity among mosquito RNA polymerase I promoters and associated regulatory elements, and contribute towards the eventual use of these elements in transgenic applications.

  18. Effect of spacers on the thermal performance of an annular multi-layer insulation

    International Nuclear Information System (INIS)

    Haim, Y.; Weiss, Y.; Letan, R.

    2014-01-01

    The current study presents a model and is experimentally conducted in a system of 40 stainless steel coaxial foils, of nitrogen gas, entrapped between the foils, and of spacers, which are zirconia, spherical, 50 μm in size particles, widely dispersed in the gaps between the foils. The model, experimentally verified, relates to radiation between the foils, unobstructed by particles, to conduction in the nitrogen gas, and to conduction across the particles. The study was, in particular, aimed to measure the effective thermal conductivity of the particles and to assess its effect upon the array. At vacuum of 0.092 Pa, the effective thermal conductivity of the particles was 2.13 × 10 −4  W/m K, while the effective thermal conductivity of the array was 4.74 × 10 −4  W/m K. Thus, the low contribution of the particles conduction at vacuum conditions improves the insulation. It reaches 45% of the heat transfer rate. At atmospheric pressure, the effective thermal conductivity of the array reaches 4.5 × 10 −2  W/m K. There, the spacers contribution is negligible. - Highlights: •The multi-layer insulation of cylinder consists of foils separated by particles. •The particles are widely spaced in gaps. •Particles heat transfer rate is almost half of the total in vacuum. •At higher pressures the particles contribution is negligible. •The predicted thermal performance agrees with experimental results

  19. Controlling the Biomimetic Implant Interface: Modulating Antimicrobial Activity by Spacer Design

    Science.gov (United States)

    Wisdom, Cate; Vanoosten, Sarah Kay; Boone, Kyle W.; Khvostenko, Dmytro; Arnold, Paul M.; Snead, Malcolm L.; Tamerler, Candan

    2016-08-01

    Surgical site infection is a common cause of post-operative morbidity, often leading to implant loosening, ultimately requiring revision surgery, increased costs and worse surgical outcomes. Since implant failure starts at the implant surface, creating and controlling the bio-material interface will play a critical role in reducing infection while improving host cell-to-implant interaction. Here, we engineered a biomimetic interface based upon a chimeric peptide that incorporates a titanium binding peptide (TiBP) with an antimicrobial peptide (AMP) into a single molecule to direct binding to the implant surface and deliver an antimicrobial activity against S. mutans and S. epidermidis, two bacteria which are linked with clinical implant infections. To optimize antimicrobial activity, we investigated the design of the spacer domain separating the two functional domains of the chimeric peptide. Lengthening and changing the amino acid composition of the spacer resulted in an improvement of minimum inhibitory concentration by a three-fold against S. mutans. Surfaces coated with the chimeric peptide reduced dramatically the number of bacteria, with up to a nine-fold reduction for S. mutans and a 48-fold reduction for S. epidermidis. Ab initio predictions of antimicrobial activity based on structural features were confirmed. Host cell attachment and viability at the biomimetic interface were also improved compared to the untreated implant surface. Biomimetic interfaces formed with this chimeric peptide offer interminable potential by coupling antimicrobial and improved host cell responses to implantable titanium materials, and this peptide based approach can be extended to various biomaterials surfaces.

  20. Serine-based gemini surfactants with different spacer linkages: from self-assembly to DNA compaction.

    Science.gov (United States)

    Silva, Sandra G; Oliveira, Isabel S; do Vale, M Luísa C; Marques, Eduardo F

    2014-12-14

    Cationic gemini surfactants have strong potential as compaction agents of nucleic acids for efficient non-viral gene delivery. In this work, we present the aggregation behavior of three novel cationic serine-based gemini surfactants as well as their ability to compact DNA per se and mixed with a helper lipid, 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE). All the surfactants have a 12-12-12 configuration, i.e. two main 12-carbon alkyl chains linked to the nitrogen atom of the amino acid residue and a 12 methylene spacer, but they differ in the nature of the spacer linkage: for (12Ser)2N12, an amine bond; for (12Ser)2CON12, an amide bond; and for (12Ser)2COO12, an ester bond. Interestingly, while the amine-based gemini aggregates into micelles, the amide and ester ones spontaneously form vesicles, which denotes a strong influence of the type of linkage on the surfactant packing parameter. The size, ζ-potential and stability of the vesicles have been characterized by light microscopy, cryogenic scanning electron microscopy (cryo-SEM) and dynamic light scattering (DLS). The interaction of the gemini aggregates with DNA at different charge ratios and in the absence and presence of DOPE has been studied by DLS, fluorescence spectroscopy and cryo-SEM. All the compounds are found to efficiently compact DNA (complexation > 90%), but relevant differences are obtained in terms of the size, ζ-potential and stability of the lipoplexes formed. Results are rationalized in terms of headgroup differences and the type of aggregates present prior to DNA condensation.